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Pulp and Paper Manufacture 


An OflBcial Work Prepared 
under the direction of the 

Joint Executive Committee of the 

Vocational Education Committees of the 

Pulp and Paper Industry of the 

United States and Canada 

Vol. I — Mathematics, How to Read 
Drawings, Physics. 
II — Mechanics and Hydraulics, 

Electricity, Chemistry. 
Ill — Preparation of Pulp. 
IV, V — Manufacture of Paper. 






Prepared Under the Direction of the Joint Executive 

Committee on Vocational Education Representing 

the Pulp and Paper Industry of the 

United States and Canada 


Preparation of Rags and Other Fibers; Treatment of Waste Papers; 

Beating and Refining; Loading and Engine Sizing; Coloring; 

Paper-Making Machines 

Anthors: E. C Tucker, A.B.; Ed. T. A. Coughlin, B.S., Ch.E.; Arthur B 

Green, A.B., S.B.; Ross Campbell, B.S.; J. W. Brassington; 

Judson A. DeCew, B.A.Se.; C. J. West, Ph.D.; James 

Bevcridge; and others. 

First Edition 


LONDON: 6 & 8 BOUVERIE ST., E. C. 4 

Copyright, 1924, by the 

Joint Executive Committee of the Vocatio>jal Education Committees 

OF the Pulp and Paper Industry. 

All Rights Reserved, 
Including Those of Translation. 




In numerous communities where night schools and extension 
classes have been started or planned, or where men wished' to 
study privately, there has been difficulty in finding suitable 
textbooks. No books were available in English, which brought 
together the fundamental subjects of mathematics and element- 
ary science and the principles and practice of pulp and paper 
manufacture. Books that treated of the processes employed 
in this industry were too technical, too general, out of date, or so 
descriptive of European machinery and practice as to be unsuit- 
able for use on this Continent. Furthermore, a textbook was 
required that would supply the need of the man who must study 
at home because he could not or would not attend classes. 

Successful men are constantly studying; and it is only by 
studying that they continue to be successful. There are many 
men, from acid maker and reel-boy to superintendent and mana- 
ger, who want to learn more about the industry that gives them a 
livelihood, and by study to fit themselves for promotion and in- 
creased earning power. Pulp and paper makers want to under- 
stand the work they are doing — the how and why of all the 
various processes. Most operations in this industry are, to some 
degree, technical, being essentially either mechanical or chemical. 
It is necessary, therefore, that the person who aspires to under- 
stand these processes should obtain a knowledge of the under- 
lying laws of Nature through the study of the elementary sciences 
and mathematics, and be trained to reason clearly and logically. 

After considerable study of the situation by the Committee 
on Education for the Technical Section of the Canadian Pulp 
and Paper Association and the Committee on Vocational Educa- 
tion for the Technical Association of the (U. S.) Pulp and Paper 
Industry, a joint meeting of these committees was held in Buffalo 



in September, 1918, and a Joint Executive Committee was ap- 
pointed to proceed with plans for the preparation of the text, its 
pubUcation, and the distribution of the books. The scope of the 
work was defined at this meeting, when it was decided to provide 
for preliminary instruction in fundamental Mathematics and 
Elementary Science, as well as in the manufacturing operations 
involved in modern pulp and paper mill practice. 

The Joint Executive Committee then chose an Editor, 
Associate Editor, and Editorial Advisor, and directed the Editor 
to organize a staff of authors consisting of the best available men 
in their special hnes, each to contribute a section dealing with his 
specialty. A general outline, with an estimated budget, was 
presented at the annual meetings in January and February, 1919, 
of the Canadian Pulp and Paper Association, the Technical 
Association of the Pulp and Paper Industry, and the American 
Paper and Pulp Association. It received the unanimous approval 
and hearty support of all; and the budget asked was raised by 
an appropriation of the Canadian Pulp and Paper Association 
and contributions from paper and pulp manufacturers and allied 
industries in the United States, through the efforts of the 
Technical Association of the Pulp and Paper Industry. 

To prepare and publish such a work is a large undertaking; 
its successful accomphshment is unique, as evidenced by these 
volumes, in that it represents the cooperative effort of the Pulp 
and Paper Industry of a whole Continent. 

The work is conveniently divided into sections, and bound into 
volumes for reference purposes; it is also available in pamphlet 
form for the benefit of students who wish to master one part 
at a time, and for convenience in the class room. This latter 
arrangement makes it very easy to select special courses of 
study; for instance, the man who is specially interested, say, in 
the manufacture of pulp or in the coloring of paper or in any 
other special feature of the industry, can select and study the 
special pamphlets bearing on those subjects and need not study 
others not relating particularly to the subject in which he is 
interested, unless he so desires. The scope of the work enables 
the man with but little education to study in the most efficient 
manner the preliminary subjects that are necessary to a 
thorough understanding of the principles involved in the manu- 
facturing processes and operations; these subjects also afford an 
excellent review and reference textbook to others. The work 


is thus especially adapted to the class room, to home study, 
and for use as a reference book. 

It is expected that universities and other educational agencies 
will institute correspondence and class-room instruction in 
Pulp and Paper Technology and Practice with the aid of these 
volumes. The aim of the Committee is to bring an adequate 
opportunity for education in his vocation within the reach of 
every one in the industry. To have a vocational education 
means to be familiar with the past accomplishments of one's 
trade, and to be able to pass on a record of present experience 
for the benefit of those who will follow. 

To obtain the best results, the text must be diligently studied ; 
a few hours of earnest application each week will be well repaid 
through increased earning power and added interest in the daily 
work of the mill. To understand a process fully, as in making 
acid or sizing paper, is like having a light turned on when one 
has been working in the dark. As a help to the student, many 
practical examples for practice and study and review questions 
have been incorporated in the text; these should be conscien- 
tiously answered. 

This volume deals with the manufacture of paper in the same 
authoritative and comprehensive manner as the subject of the 
manufacture of pulp was covered in the preceding volume. In 
spite of the antiquity of the paper industry, recent developements 
have been remarkable. There is still almost unlimited oppor- 
tunity for exhaustive improvement in equipment and operation, 
and further advances will result from the study of what has 
already been accomplished. The progress that has been made 
in paper manufacture is expressed in the carefully prepared and 
exceptionally well illustrated text of this volume and the volume 
that follows. The importance of paper — its place as an absolute 
necessity in civihzed life — is now fully recognized; and every one 
should be interested in and be able to understand the descriptions 
herein given of the processes and equipment involved in its 
manufacture. Never have such care and expense been devoted 
to the preparation of an industrial textbook. 

A feature of this series of volumes is the wealth of illustrations, 
which are accompanied by detailed descriptions of typical 
apparatus. In order to bring out a basic principle, it has been 
necessary, in some cases, slightly to alter the maker's drawing, 


and exact scales have not been adhered to. Since the textbook 
is in no sense a "machinery catalog," maker's names have been 
mentioned only when they form a necessary descriptive item. 
Much of the apparatus illustrated and many of the processes 
described are covered by patents, and warning is hereby given 
that patent infringements are costly and troublesome. 

A valuable feature of this work, which distinguishes it from all 
others in this field, is that each Section was examined and 
criticised while in manuscript by several competent authorities; 
in fact, this textbook is really the work of more than one hundred 
men who are prominent in the pulp and paper industry. With- 
out their generous assistance, often at personal sacrifice, the 
work could not have been accomplished. Even as it stands, 
there are, no doubt, features that still could be improved. The 
Committee, therefore, welcomes helpful criticisms and sugges- 
tions that will assist in making future editions of still greater 
service to all who are interested in the pulp and paper industry. 

The Editor extends his sincere thanks to the Committee and 
others, who have been a constant support and a source of in- 
spiration and encouragement; he desires especially to mention 
Mr. George Carruthers, Chairman, and Mr. R. S. Kellogg, 
Secretary, of the Joint Executive Committee; Mr. J. J. Clark, 
Associate Editor and Mr. T. J. Foster, Editorial Advisor. 

The Committee and the Editor have been generously assisted 
on every hand; busy men have written and reviewed manuscript, 
and equipment firms have contributed drawings of great value 
and have freely given helpful service and advice. Among these 
kind and generous friends of the enterprise are: Mr. M. J. Argy, 
Mr. O. Bache-Wiig, Mr. James Beveridge, Mr. J. Brooks Bever- 
idge, Mr. H. P. Carruth, Mr. Martin L. Griffin, Mr. H. R. 
Harrigan, Mr. Kenneth T. King, Mr. Maurice Neilson, Mr. Elis 
Olsson, Mr. J. S. Riddile, Mr. George K. Spence, Mr. Edwin 
Sutermeister, Mr. F. G. Wheeler, and Bird Machine Co., Cana- 
dian IngersoU-Rand Co., Claflin Engineering Co., Dominion 
Engineering Works, E. I. Dupont de Nemours Co., General 
Electric Co., Harland Engineering Co., F. C. Huyck & Sons, 
Hydraulic Machinery Co., Improved Paper Machinery Co., 
E. D. Jones & Sons Co., A. D. Little, Inc., E. Lungwitz, 
National Aniline and Chemical Works, Paper Makers Chemical 
Co., Process Engineers, Pusey & Jones Co., Rice, Barton & Fales 
Machine and Iron Works, Ticonderoga Paper Co., Waterous 


Engine Works Co., Westinghouse Electric & Manufacturing Co., 
and many others, particularly the authors of the various 
sections, who have devoted so much time and energy to the 
preparation of manuscript, often at personal sacrifice. 

J. Newell Stephenson, 



Joint Executive Committee on Vocational Education, 
George Carruthers, Chairman, R. S. Kellogg, Secretary, 

T. L. Crossley, R. S. Hatch, G. E. Williamson. 

Representing the Technical Sec- Representing the Technical As- 
tion of the Canadian Pulp and Paper sociation of the (U. S.) Pulp and 
Association. Paper Industry. 

T. L. Crossley, Chairman, R. S. Hatch, Chairman, 

George Carruthers, R. S. Kellogg, 

A. P. Costigane, F. C. Clark, 

C. Nelson Gain, W. S. Lucey, 

J. N. Stephenson. Ernst Mahler, 

J. D. Rue, 
A. D. Wood. 



Preface v 


Preparation of Rag and Other Fibers 

Introduction 1-4 

Sources of Supply 4-6 

Classification of Rags 6-9 

Treatment of Rags before Cooking 9-17 

Cooking of Rags 17-30 

Bleaching, Draining, and Losses 30-39 

Hemp, Jute, Seed-Hull Fiber, etc 39-46 

Esparto 46-54 

Straw Pulp 54-59 

ExTamination Questions 62 

Treatment of Waste Papers 

Use and Value of Waste Papers 1-3 

Methods of Recovery 3-8 

Mill Sorting 9-16 

Dusting the Papers 17-19 

Paper Shredders 19-25 

Purchasing Paper Stock 25-28 

Cooking Processes 28-57 

Treatment of Cooked Paper Stock 57-70 

Examination Questions 71-72 


Beating and Refining 

Introduction 1-4 

Types of Beaters 4-19 

Care of Beaters 19-21 

Beater-Room Equipment 22-36 

Condition and Handling of Pulps and Half-Stuff 37-45 

Theory of Beating 45-64 

The Jordan Refining Engine 65-68 

Special Types of Refining Engines 68-70 

Bibliography 71-77 

Examination Questions 79-80 




Loading and Engine Sizing 



Fillers 1-3 

.soukcks and character of fillers 4-16 

Analysis of Fillers 17-22 


Engine Sizing — Historical 23-24 

Materials Used in Sizing 24-28 

The Sizing Process 28-44 

Sizing Different Kinds of Paper 45-47 

Examination Questions 49 


Introduction 1-4 

Classification of Coloring Materials 4-11 

Sources and Manufacture of Aniline Dyes 11-13 

Standardization of Dyestuffs 13-15 

Testing of Dyestuffs 15-31 

Color-Storage and Preparation Rooms 31-34 

Details of Coloring Process 34-40 

Color Formulas 40-46 

Calender and Other Methods of Coloring 46-52 

Examination Questions 53-54 


Paper-Making Machines 


General Description 1-3 

Paper-Machine Room 3-5 

Important Auxiliary Equipment 5-26 

Screens 26-34 

Origin of Modern Paper Machine 34-38 

Fourdrinier Part of the Paper Machine 38-41 

Details of Fourdrinier Part 41-74 

Management of Fourdrinier Part 74-80 

Operating Details and Troubles 80-95 

Examination Questions 97-98 




De-Watering the Paper 99-101 

Description of Press Part 101-106 

Details of Press Part 106-118 

Management and Care of Press Part 118-137 

Examination Questions 139-140 


The Smoothing Rolls 141-144 

A Typical Dryer Part 144-150 

Details of Dryer Part 150-159 

Operation and Management of Dryers 159-164 

Dryer Felts and Evaporative Effects 164-176 

Examination Questions 177-178 


The Calender End 17&-187 

Reels 187-196 

Slitters and Winders 196-205 

Winding Troubles 205-207 

Examination Questions 209-210 



By E. C. Tucker, A. B. 



1. A Brief History of the Use of Rags in Paper Making. — The 

earhest human records were made on stone; in some countries 
scratched or chiseled, in others written with chalk or colored ore. 
Other and more convenient substances used later in various 
places were, pieces of wood — as bamboo, bark, leaves — and 
prepared skins, as parchment and vellum. At a very early date, 
the Egyptians prepared a writing material from papyrus, a tall 
reed growing in the Nile, and called it also papyrus, whence our 
word paper. It was made by peehng off the layers of the stem, 
laying the long ones side b}- side until a strip of the desired width 
was obtained, then crossing them with short pieces. The sap 
served as an adhesive; and, after drying in the sun, the papyrus 
could be rubbed to a surface that could be written on with ink. 
A shortage of papyrus in Asia ]\Iinor resulted in the invention 
of parchment, a specially dried calf or goat skin, filled by rubbing 
in chalk. Because of a similar famine in Rome, hoards, covered 
with wax, were used; they were written on with a sharp instru- 
ment called a stylus. Several layers of wax were sometimes put 
on the same tablet. 

2. The earl}' Greeks wrote letters, notes, mortgages, etc. on 
broken pieces of pottery. The Chaldeans and Syrians wrote 
their records in soft clay bricks, which were then baked. 
Librarians must have used wheelbarrows! 

§1 1 


The Chinese were the first real pulp and paper makers. They 
soaked pieces of bamboo in pits of lime water and separated the 
fibers by pounding. Rag and other fibers were also used, the 
process of making the paper being essentially the same as in use 
now in making hand-made papers. 

3. At the dawn of the Christian era, paper making from rag 
fibers was a well-established art in China. From there the 
secrets of the process spread westward, and were carried to 
Europe by the invasions of the barbaric tribes. During the 
middle ages, the process was improved and developed, and by 
the end of the fourteenth century it was firmly established 
throughout southern Europe. 

In England, the development was very slow, for it was not 
until three centuries later that the industry took firm hold there. 
As would be expected, the delay with which the industry was 
developed in England was further reflected in this country, and 
it was not until the last half of the eighteenth century that paper 
making became common here, although the first mill was 
established in 1690, and the industry developed without 

4. Early Methods of Converting Rags into Paper. — The early 

phases of the development of paper making are interesting. 
The first process for converting the rags into paper was crude 
and primitive. The rags were washed, and were then steeped in 
closed vessels for several days. During this treatment, a 
fermentation process took place which brought the mass to a 
pasty consistency. This pulp was then diluted, transferred 
to the vat, and made into sheets on a hand mold. (See Hand- 
made Papers, Vol. V.) The first advance from this method came 
with the introduction of stamping rods, to beat the rags into 
pulp ; and this was the process in use in practically all of the small 
mills previous to 1750. The rags were washed, and were then 
transferred to oak tubs or mortars, partly filled with water. 
Here the rags were beaten and pulped by stamping rods, 
which were encased with an iron shoe at one end. In most 
of the mills, these stamping rods were operated b}^ power 
from a small stream — in a few cases they were operated by 
hand. By this method, using water power, from 100 to 125 
pounds of rags would be reduced to pulp in 24 hours in a 
typical mill. 


5. During the period from 1750 to 1800, the Hollander beater 
engine was developed and brought into general use. This was 
a small and early type of the boating engine so well known today. 
Its introduction brought the first decided change in manufactur- 
ing equipment. It improved quality, increased production, and 
made possible the later rapid growth of the industry. 

6. Paper-Making Raw Materials.^ — Prior to 1860, rag fibers, 
cotton and linen (with small quantities of jute and hemp), 
formed the total source of paper-making raw materials. Rags 
were used in all grades of paper, from news and wrapping paper to 
writing paper. This condition made rags very scarce, in spite 
of large importations from Europe. In 1850, more than twenty 
million pounds of rags were imported by the United States, and 
still the mills were short of raw material. The newspapers and 
periodicals of those days were full of pleas from paper-mill pro- 
prietors, asking the people to save their rags for some particular 
paper mill. The difficulty in obtaining a sufficient supply of 
raw material was the determining factor in the industry. 
Expansion was almost impossible. 

The discovery of the processes of making pulp from wood — the 
soda, sulphite, and groundwood processes — finally relieved this 
situation, and gave the industry the opportunity to grow. 

7. At the present time, most of the rags go into the class of 
paper known as fine writing, and for this type of paper the fiber 
from cotton or linen cloth has no equal; large quantities of low- 
grade rags are used for roofing papers, while burlap, strings 
(jute) and hemp rope are used for strong wrapping papers 
(manilas). These fibers are prepared for use directly in the 
paper mill, as distinguished from wood fibers, which receive 
their first treatment in the pulp mill. For this reason, and 
because of the considerable similarity in processes and apparatus, 
the preparation of straw and esparto grass is also included in 
this Section. The treatment of waste papers is covered in 
another Section. 

Note. — Cotton^ (gossypium). The cotton fiber, which is the basis of 
most rag papers, consists of a single hair-like cell, which is flattened and 
twisted when fully ripe. This appearance is a characteristic of fully matured 
cotton; it is not shown by unripe fiber or by that which has been injured 

^ Data on the characteristics of paper-making fibers, given in these 
notes, are based on information derived from Chemistry of Pulp and Paper 
Making, by E. Sutermeister. See also Section 1, Vol. III. 


during growth. The fibers form the covering of the cotton seed, and they 
are removed from the seed by ginning. Tlie length of the cotton fiber varies 
from 2 to 5.6 cm., and the diameter varies from 0.0163 to 0.0215 mm. The 
cell walls of mature cotton are thin, and they often present a granulated 
appearance or highly characteristic cross markings. IMuller has analyzed 
raw cotton, with the following results : 

Per Cent 

Water 7 . 00 

Cellulose 91 .35 

Fat 0.40 

Aqueous extract (containing nitrogenous substances) . 0.50 

Ash 0.12 

Cuticular substance (by difference) 0.63 

Total 100.00 


8. New Rags, or Table Cuttings. — The supply of new rags for 
paper making comes largely from textile or garment factories, 
where cuttings and scrap ends of cloth are collected as by- 
products. The total amount of cuttings available from this 
source of supply is estimated at 40,000 tons per year. The 
only other use for this material seems to be the re-spinning of 
white knitted goods, and this in quantity only when the price 
of raw cotton is high. 

This waste material is usually sold to a broker or middleman, 
who takes the entire accumulation of the individual factory; 
and it may include everything, from the floor sweepings to 
the choicest clippings of white linen or cotton. The middleman 
usually repacks this material and then sells it to the paper mills 
that use the different grades. 

9. Old Rags. — The source of supply of old rags is quite differ- 
ent. In the first place, it is much more flexible. Being a waste 
product, so common to every home, there is little likelihood of a 
shortage; for a rise in price will always bring out rags. We are 
all familiar with the grotesque figure that travels our streets 
and alleys buying "ra — gs" from the housewife. His capital 
consists of a dejected horse and a dilapidated wagon. Each 
night he sells his day's collection to another rag man who owns a 
small warehouse, and who buys these mixed rags and l)ales 
them in carload lots, for sale to the grader. The grader sorts 


the rags for re-sale (sometimes directly and sometimes through a 
broker) to the paper mill, in the case of cottons, or to the shodd}^ 
mill, in the case of woolens. The following figures give a slight 
idea of what a thousand pounds of mixed rags contain. 

Paper-Makixg Rags 


No. 1 whites 25 

No. 2 whites 50 

Whites and blues 225 

Jute bagging 125 

Roofing stock 250 

Non-Paper-Making Rags 


Soft woolens 20 

Hard woolens 125 

Mixed linseys (half wool and half cotton) 20 

Wiping rags 60 

Quilts and white batting 85 

Rubbish 15 


Total 1000 lb. 

10. Uses of Rags. — Xo. 1 whites. No. 2 whites, and whites 
and blues, (known also as either two's and blues or thirds and 
blues) are used for writing paper, and the specifications for each 
of these grades will be found in Arts. 13 and 14. The jute bagging 
is used by the wrapping-paper mill, and the roofing rags are used 
for making roofing paper. This is the lowest grade of stock; 
it includes everji;hing, so long as it is rag. 

The woolen rags go to the shodd}' mills; they bringby far the 
highest prices of any of the grades. 

Wiping rags are used by machine shops, etc., and consist of 
large pieces of good, sound colored cloth. 

Quilts and batting go to the mattress industrj\ The rubbish 
consists of such material as old straw hats, shoes, etc., which 
must be baled and carted to the dump. 

11. Transporting and Handling Rags. — Rags are transported 
and handled in machine-pressed bales that weigh from 400 to 
1000 pounds, depending on the size and type of press. The 


hand baling press is still largely used; it is by far the most 
economical method of baling where only a small number of bales 
are made each day. With this type of press, two men will turn 
out from 10 to 15 bales a day. 

Where the volume of baling to be done is large enough, the 
power press is of course more economical. There are several 
types of those presses on the market any one of which does 
excellent work. A bale weighing 600 to 800 pounds is large 
enough for convenient handling in the mill. 



12. General Specifications. — There are certain general rules 
which should apply to all grades. Rubber, for example, in any 
form is a distinct menace to the manufacture of good paper; 
and it should be generally understood that rubber is not to be 
included in any of the packings of rags that are to be used for 
the manufacture of writing paper. 

All grades, new^ and old, must be free of rubber, leather, wool, 
silk, paper or muss, unless otherwise specified. It is recom- 
mended that where a description of any grade is not available, 
the material is to be sold on specified sample. 

Other general specifications, which should cover all grades of 
rags, unless they are sold strictly on representative samples, are : 
the}^ should be dry, and they should be free from paint, grease, 
and other foreign materials. 


13. Old Rags. — Old rags are divided into various grades, each 
of which has its own trade name and specifications, which are as 
follows for old rags: 

Extra No. 1 white cottons consist of large, clean, white cottons, 
free from knits, ganzies, canvas, lace curtains, collars, cuffs, shirt 
bosoms, bed spreads, new cuttings and stringy or mussy rags. 

No. 1 white cottons consist of clean white cottons, free from 
lace curtains, ganzies and canvas. Need not be so large as 


Extra No. 1 white cottons. Must not contain stringy or 
mussy rags. 

No. 2 whites consist of soiled white cottons, free from dump 
rags, street rags, scorched rags, paint, greasy rags, or oily rags. 
Also free from button strips and seams from higher grades of 

Mixed whites should contain at least 40% of No. 1 whites 
and not more than 60% of No. 2 whites. They must not contain 
any of the material prohibited in the grades of which they are 

Street whites should consist of soiled white cottons from 
street or dump collection. They are likely to contain some 
foreign material, resulting from the manner in which they are 
collected, but the rags must be dry. 

Twos and blues should be rags of strictly house collection, 
and should consist of No. 2 white cottons and light blue 
checks and prints. They should not contain the seams or 
buttons taken from higher grades of whites, nor should 
they contain dark blues of any description. They should not 
contain old corsets, small pieces of new rags, or rags smeared 
with paint, oil, or grease, nor should they contain any scorched 

Thirds and blues should be rags of strictly house collection, 
and may contain light pinks, greens, and blues, but should be free 
from dark reds, yellows and blacks, from quilts and feather 
ticks, canvas, tents and awnings, seams and stoppings from 
higher grade rags, from rags smeared with paint, oil, or grease, 
and from small pieces of new rags or fine cut mussy rags. 

Miscellaneous blues should be rags of all colors, free from 
solid black or satinet. Street or dump rags must not be present 
in excess of 25%. 

Old blue overalls are to contain clean, blue overalls only^ free 
from oil, grease or paint, and are understood to be free from 
miners' garments. 

Black cotton stockings are to consist entirely of black cotton 
stockings, but white feet or edgings are permitted. 

White cotton batting should contain only clean white cotton 
from quilts, mattresses and comforters; must be stripped of all 

White cotton-filled quilts should be quilts filled with white 
cotton batting onl}-. 


No. 1 white old lace curtains are to contain only clean, white 
lace curtains, free from starchy, knitted or crocheted material. 

Besides these grades there are special classifications, such as 
underwear, flannelettes, hosiery, tarpaulins, filter press canvas, 
strings, rope, burlap, roofing stock, etc. 

14. New Rags. — For new rags, the names of the grades and 
their specifications are: 

No. 1 white shirt cuttings, heavy, are to consist of white 
cuttings such as accumulate from shirt factories and similar 
sources; must be strictly table cuttings and are to be free of 
starchy or loaded material. B.V.D. cuttings (dimity) may be 

No. 1 white shirt cuttings, lawns, may contain materials of 
lighter weight than heavy shirt cuttings; they must be table 
cuttings and free of starchy or loaded material. 

No. 2 white shirt cuttings are to consist of white shirt cuttings 
and lawns, consisting of house to house and shop collections, 
and not of table cuttings; may contain a small percentage of 
black threads, muss and soiled material; are to be free from oily 

No. 1 bleached strips, white or gray, are to consist of strips of 
white or gray cotton cuttings, coming from bleacheries; must be 

No. 1 soft unbleached cotton are to consist only of unbleached 
cuttings of a character similar to white shirt cuttings, heavy. 
Must be free of starchy or loaded rags, Canton flannels, shivy 
rags and drills. 

No. 1 bleached shoe cuttings should be table cuttings of a 
nature used in lining shoes; are to be free of pasted stock. 

No. 2 bleached shoe cuttings are the same as No. 1, but may 
contain pasted stock. 

No. 1 unbleached shoe cuttings are to be the same as No. 1 

bleached shoe cuttings, with the exception that they are to 

consist of unbleached cuttings and are to be free of pasted stock. 

No. 2 unbleached shoe cuttings are the same as No. 1, but may 

contain pasted stock. 

No. 1 fancy shirt cuttings are to be such table cuttings as 
accumulate from shirt factories and similar sources, consisting 
of white background with colored stripes. 

No. 2 fancy shirt cuttings are to be composed of the same 
material as No. 1 fancy shirt cuttings, with the exception that 


they need not be table cuttings; but must consist of material 
coming from house to house and shop collections; may contain 
black threads and soiled pieces. 

Blue overall cuttings are to be such table cuttings as accumu- 
late from overall factories and similar sources. This grade 
should be accompanied by sample showing whether the weave 
consists of a black-thread or white-thread back. 

Washables or wrapper cuttings must be table cuttings; may 
contain material of hghter weight than fancy shirts, such as 
cahcoes, ginghams, etc.; may contain sohd colors, but are to be 
free of reds and blacks; 

New light seconds are to consist of sheer, flimsy rags, light 
colored; sohd colors are to be admitted or white backs with 
colored stripes. Need not be free from black threads. 

Soiled bleachery rags are to consist of cuttings and remnants 
coming from bleacheries; may be soiled, but must be free from 
oil and grease. 

No. 1 dark prints are to consist of all dark colors and unbleach- 
able new material. 

Cottonades are to consist of coarse, striped cotton-garment 
cuttings that look like wool but are free from wool. Brown 
cuttings and striped overalls may be included. 

Besides the classes given, there are other grades and subdivi- 
sions. An interesting article on Rags, by Howard Atterbury, 
appeared in the Pulp and Paper Magazine, 1919, p. 1103. 



15. The Rag Thrasher. — The first step in the actual prepara- 
tion of rags for paper making is the preliminary thrashing. • 

The bales are opened up and the rags put through a rag 
thrasher, though some mills pass new rags directly to the sorters. 
The purpose of this machine is to open the rags up thoroughly, 
and to remove the loose dirt and dust that may be present. 

The rag thrasher consists of a revolving cylindrical drum A, 
Fig. 1, about 40 inches in diameter, from which protrude hooks 
or pins B for thrashing the rags. The cylinder is enclosed, and 
there is a hopper C and gate D on one side for feeding in the rags, 


and a gate E on the other side, for discharge after the rags are 
thrashed. Under the cyUnder is a coarse screen F, which allows 
the dirt to drop through, but which holds the rags in contact with 
the drum. At the top, a stick of timber G, about 12 inches 

from the drum, serves as a whip 
as the rags beat against it. Fine 
dust held in suspension is re- 
moved by a suction fan through 
the pipe H. The dirt is shoveled 
out from below the screen. 

In operation the hopper is 
filled, then the gate is opened, 
and the rags are allowed to slide 
into the thrasher. After 4 or 5 
minutes' thrashing the rags 
are discharged by raising the 
gate on the other side. They 
are then ready for the sorters. 

16. Thrasher Dust and Loss 
in Weight. — ^Loss in weight due 
to the amount of dust and dirt taken out by the thrashers depends 
largely, of course, on the character of the rags going in. In the 
case of new table cuttings, the loss is ver}^ small; while in the case 
of street whites, it may run as high as 8% to 10 % or higher. 

Fig. 1. 


17. Sorting Rags. — From the thrasher, the rags usually are 
loaded into baskets and turned over to women, who strip and 
sort them. These sorters work at tables, Fig. 2, which are really 
shallow boxes with a coarse screen bottom. Large scythe-like 
kijives are used for stripping buttons, ripping seams, cutting 
large rags, etc. In the case of new rags, there is usually very 
little stripping to do. The sorters in this case look particularly 
for foreign material, such as metal, rubber, leather, etc., that 
must be taken out, and also for the occasional pieces of silk or 
wool or paper that may be there. Pockets are always searched; 
the findings include knives, rings, money and trash. 

In the case of old rags, the sorter's work is more difficult. 
These old rags consist mainly of cast-off cotton garments. 





These garments must first be stripped on the knife; that is, the 
buttons arc stripped off, the pockets and heavy seams ripped up, 
and all metal is taken off. When this is finished, the rags are 
graded as to color, where this is necessary', separate baskets 
receiving the different grades and colors; for instance, yellows 
and reds, known as "hard" colors, as they are hard to bleach, 
are saved for dark-colored paper. The strippings and discarded 
stock make what the paper maker knows as muss, and this 
material goes into the manufacture of roofing paper. Good 
woolens go to the shoddy industry. 

18. Why Rubber and Metal Are Avoided. — Perhaps the reader 
is wondering why the paper maker speaks so often of rubber and 
metal, and is so anxious to avoid them. It is due to the desire 
on his part to make clean paper. Hold a sheet of writing paper 
up to the light and look for the dirt. Now rubber and metal 
are not affected by the cooking, the washing, or the bleaching. 
Once in, they go straight through the process, only getting cut up 
into small pieces and finally spreading through the whole web 
of paper. "But," one may ask, "How is it that you sometimes 
find such things as rubber in new cuttings of cotton cloth?" 
It is there because of the large amount of rubber used in making 
cotton garments. There are rubber waist bands, sleeve bands, 
dress shields or goods waterproofed or pasted together with 
rubber. Such things as these, carelessly allowed to go in with 
good material, cause losses of thousands of dollars annually to 
the paper industry. Constant alertness is the only safeguard 
against troubles of this sort. 

19. Inspection of Rags. — Rags coming from the sorters are 
usually sent to the inspectors or "over-lookers." These women 
go over the rags again very carefully, to make certain that all of 
the objectionable material is removed from the rags before it is 
passed on to the next process. The rag sorters must do con- 
scientious work, if the mill is to make clean paper. Workers 
in the rag room are usually paid a certain amount per pound for 
rags sorted. This weighing is also a check on the quality of rags 
and quantity used. 

20. Equipment of Rag-Sorting Room. — The equipment of 
the rag-sorting room is not elaborate. The rags are handled in 
large baskets, which are provided with casters, for ease of moving 
from place to place. The sorters work on tables provided with 


half-inch-mesh wire screens on the working surface, this allows 
dirt, loose buttons, etc., to drop through into a box. Each of 
the sorters has, in addition, the stripping knife, set up in a 
convenient place on the table or screen at which she works; this 
is a source of accidents, usually of a minor nature, but likely 
to cause infection; even a scratch should be given first-aid 

Particular attention must always be given to the ventilation 
of the rag room, and a special ventilating system should be 
provided to remove the dust and lint that always comes from 
handling the rags. A fan usually draws the dusty air in a 
gentle stream from just below the screen and dehvers it to a 
large chamber, where the air practically comes to rest, and the 
dirt settles out. 


21. Reason for Cutting. — As the rags come from the sorters 
and inspectors, they are in fairly large pieces. In order to 
prevent them from roping, to produce uniform half-stuff (washed 
rags), and to facilitate handling all along the line, the rags are 
cut into pieces averaging in area from 10 to 20 square inches. 
For many years this work was done by women; now, however, 
the rag-cutting machine is practicall}^ always used, except in the 
case of linen rags, where the hand-cutting of rags is still quite 

22. Rag Cutters. — The essentials of this cutter, Fig. 3, are a 
revolving knife cutting against a bed knife (like a lawn mower), 
and the means of feeding the rags to this knife. In many of the 
mills, two cutters in tandem are used. Tandem cutters are 
set at right angles so as to cut the rags in both directions. 

23. One of the most recent machines on the market is the 
rag cutter, shown in Fig. 3. This machine uses slitters before 
the knife, and its operation is as follows: The rags are placed 
in the feed apron U at the top, and from there thej^ fall in between 
the corrugated knives, or slitters X, which constantly rotate and 
slit the rags into strips lengthwise. The rags are stripped off 
these slitters by another set of corrugated rolls, and clearers, 
and fall into the intermediate, or slat, apron. This carries the 
strips along and feeds them endwise to the fly knife A, which 


turns against a stationary bed knife and chops off the strips into 
rectangular blocks. The cut rags then fall to the delivery apron 
W, which carries them to the duster. All gears should be 
enclosed and care taken to keep hands from the knives. The 
bed knife is lowered or lifted by means of hand wheels H and 
screws, so as to regulate the distance from edge of bed knife to 
flv knife .4. 

Fig. 3. 

24. Dusters. — Rags, coming from the rag cutter, carry with 
them the dust produced by the cutting operation. This dust is 
too short-fibered to be of use, and would be lost in the later 
processes; it also carries with it a verj^ considerable amount of 
dirt, which has to be taken out, if clean paper is to be made. 
For this purpose, different types of dusters are in use. Very 
often the rags are discharged from the rag cutter to a railroad 
duster. In this type of duster, revolving drums A, Fig. 4, with 
pins or teeth arranged helically around the drum, carry the rags 
over fine screens C. This type of duster is very simple. The 
rags are fed in at D ; after passing the screen, they are deflected to 




the next drum bj' the shape of the hood at E. This duster is 
rather harsh in its treatment of the rags, and the fiber loss is 
considerable. On the other hand, the harsh treatment elimi- 
nates a large amount of dirt, so that its use is common on old 
rags. The dirt collects in the box below the screen. The rags 
usually fall from the outlet F upon an apron conveyor. 

Fig. 4. 

Another type often used is the fan, or wing, duster. Fig. 5. 
Here the rags are blown through the duster b}- a revolving drum 
A, with wings B arranged helically. At the same time, the out- 
side screen C revolves in the opposite direction. D is the dust 
outlet. This makes an excellent duster, and is a type very 
generally used. Here the treatment is not so severe, and the 
fiber loss is less. 



The cut rags are handled from the rag cutter to the boiler on 
aprons or in chutes; hence, the cutting, dusting and loading of 
the boiler really take place as one operation. Often, however, 
it is necessary to prepare and pile the rags in advance. 

Fig. 5. 

25. The Magnetic Roll. — In spite of all the care used in sorting 
and inspecting the rags, if metal is present, a certain amount of 
it always gets by. The magnetic separating roll, Fig. 6, has 
been applied, within the last few years, for removing as much as 

Fig. 6. 

is possible of this material. The magnetic pulley A is placed as 
the driving roll on one of the aprons B carrying the cut rags. 
Rags C containing iron or steel chng to the pulley, and are thus 
separated from the other rags D. 


The following extract from a letter written by a manufacturer, 
in whose mill a magnetic separating pulley has been installed, 
gives some idea of what this pulley can accomplish : 

"Tests show that we are taking out approximately 500 pieces of metal 
from each 10,000 lb., of old rags, run through. This material consists of 
hooks and eyes, metal clasps, tacks and nails, metal buttons, pins, needles, 
pieces of wire, etc., which are not detected bj- the women inspecting the rags. 
We estimate from several tests that this is about 75 % of the material which 
it would be possible to take out in this way. 

Our separator roll is 12 inches in diameter, and is run at 76.8 r.p.m. 
This gives us an apron speed of 241 feet per minute." 


(1) Name some of the materials first used for keeping records. 

(2) As regards source of supply and character, how do new rags differ 
from old rags? 

(3) (a) Of what do the sortings from paper-making rags consist? (6) 
what uses are made of them? 

(4) How much loss is suffered in thrashing? 

(5) (a) Mention some sources of rubber and iron in rags; (h) what effect 
have they on paper? 

(6) Explain one type of duster and what it does. 



26. Purpose of Cooking. — It may now be asked why the paper 
maker cooks the rags before making them into paper? In other 
words, what does this cooking process accomplish? We know 
that wood is cooked to get rid of the impurities (particularly 
lignin), and a pure cellulose is left. Now linen and cotton fibers 
are the nearest thing to be had in nature that corresponds to 
pure cellulose; but the rags used in paper making contain many 
undesirable impurities, which should be removed. First of all, 
the cooking softens and mellows the rag by removing the natural 
waxes and resinous material in the fiber. In addition, it removes 
the dirt and grease and loosens up the starch and loading material. 
It also starts the color in rags that have been dyed, and thus 
renders them readily bleachable. In some mills, it is the practice 
to take certain new white cuttings directly to the washing 


engine, leaving out the cooking process. The writer does not 
consider this to be the best practice, although it is feasible in the 
case of new white cuttings. These rags are harsh, and they do 
not respond nearly as well to treatment as in the case where the 
same rags are mellowed by the cooking process. Uncooked rags 
are usually rather difficult to size properly; because, where the 
natural waxes have not been cooked out, the capillary attraction 
of the central canals is very hard to overcome with rosin size. 
Several high-grade mills have thoroughly tried out this practice, 
and the}' now insist that all rags shall be cooked. 

Note. — IMost of the fibrous raw materials that are treated in the paper 
mill are relatively pure cellulose, which is practicalh' unaffected b}^ the 
relatively mild alkaline cooking liquors and the weak oxidizing action of 
bleach solutions, in properly conducted mill operations. Cotton, linen, 
hemp and jute have already passed through operations, incidental to the 
textile and cordage industries, which have largelj'^ removed the non-cellulose 
matter originally associated with the fiber. With esparto, straw, bagasse, 
etc., the treatment is necessarily more severe than with textile wastes; but 
here too, the recovered cellulose has come through unaffected, because of its 
wonderful resistance to most chemical agents. Some of the more important 
reactions of cellulose have been mentioned in the Section on Chemistry, 
Vol. II, and the Section on the Properties of Wood, Part 2, Vol. III. 

27. Cooking Liquor. — There are three different cooking liquors 
in general use in cooking rags: the liquor made with caustic lime; 
that made with caustic soda; and that made by using a combina- 
tion of caustic lime and soda ash. Much has been written and 
said as to the advantages of an^^ one of these processes over each 
of the other two, widely divergent opinions have been expressed, 
and two investigators reach diametrically opposite conclusions. 
Such being the case, no attempt will here be made to settle this 
argument. It is reasonably certain, moreover, that with careful 
handling, rag pulp (half-stuff) that is of excellent qualitj^ can be 
produced with any one of these cooking liquors. A few of the 
points usually brought up in a discussion of this subject may be 
of interest, however. 

28. Lime or calcium hydrate attacks the natural waxes 
energetically, and at a temperature of 120°C. (248°F.) they are 
saponified in less than two hours. Lime also attacks, but less 
readily, the oils or grease that may be present in the rags. The 
one big drawback is that it forms calcium salts, most of which are 
not soluble, and, being rather sticky, they adhere to the fiber. 


This makes the washing much more difficult, since the small 
particles of lime soap must be carried away mechanically in the 
wash water. It is to be noted, however, that this is not an 
insurmountable obstacle, and that rags cooked with lime are 
being washed satisfactorily all over the country every day. In 
addition, it is to be remembered that lime is especially adapted to 
the decomposition of a large number of dyestuffs used in coloring 
cloth; being a weak alkali, it has no action on cellulose. Conse- 
quently, it is used very widely because of the excellent color 
obtainable with it. Paper makers have long claimed that when 
lime is used in the cooking, the resulting product does not have 
nearly as much tendency to turn yellow as is the case when caustic 
soda or soda ash is used. 

29. Caustic soda is of course a more active agent than lime. It 
readih^ attacks the natural waxes and the oils or grease that may 
be present in the rags. It removes glues and starch sizings 
thoroughly, and it forms products that are soluble in water and 
which are easilj^ washed out. In strong solutions and at high 
temperature, the cellulose itself may be acted on. The writer's 
experience has been, however, that it does not attack the colors 
as thoroughly as does lime. 

30. The liquor made with a combination of Hme and soda ash 
is, of course, a mixture of the other two, with a certain amount 
of calcium carbonate in suspension. The soda present increases 
its causticizing action, and it more effectually removes the album- 
inous substances that may be present. As with the lime alone, 
however, the resulting products are all insoluble, since any 
sodium salt formed will immediately be precipitated by the lime, 
to form the calcium salt and caustic soda. Rags of dark color 
and very dirty rags are best cooked in the caustic soda or lime- 
soda ash liquor. When lime CaO and soda ash NaiCOa are 
mixed in solution, the lime first forms the hydrate Ca(0H)2, 
then the following reaction occurs: 

Ca(0H)2 + NaoCOs = CaCOs + 2NaOH 

The CaCOa, calcium carbonate, settles out, leaving a solution of 
caustic soda NaOH. 

31. The tank in which the liquor is prepared is usually so situ- 
ated that the liquor can be transferred to the boiler by gravity, 
through pipes; it usually holds the quantity required for one cook 
or one "bleach." If lime is used, the tank should contain an 


agitator, similar to that in a vertical stuff chest (See Section on 
Beating and Refining); and the resulting liquor should be 
screened before going to the boiler or to storage, in order to make 
sure that all lumps are removed. When lime and soda ash are 
used, the latter should first be dissolved, then the necessary lime 
should be added and well stirred. Let settle, and draw off 
through a strainer. 


32. Types of Boilers. — The cut and dusted rags are usually 
fed into the boiler by a chute, which feeds into the manhole at 
the top. In the rotary boiler, which is the one in general use, 
the rags must be packed into the boiler by a man inside. This 

Fig. 7. 

man tramps down the rags and stows them into the sections of 
the boiler not reached by the chute. He should wear a respirator 
to keep dust from his lungs. When the boiler is partly filled, 
the cooking liquor is started in, for when the rags are wet they 
pack much more closely. It is essential that the boiler be packed 
evenly and well to obtain uniform cooking. The liquor pipe is 
introduced through the manhole at which the man is not work- 
ing. An open vertical pipe, stuck into the boiler, assists in find- 
ing the liquor level. 

33. The boiler in general use in this country is the cylindrical 
rotary shown in part section in Fig. 7. This is a large cylindrical 
drum (usually about 8 feet in diameter by 24 feet in length) of 
such dimensions that it will hold about 5 tons of rags. In prac- 
tice, the cooking liquor, made up with water if necessary, is 
brought up to the level of the journals Ti and T2 and, in some 




cases, even filling the boiler two-thirds full; more water forms as 
the cooking steam condenses. During the cooking process, this 
boiler turns at the rate of about one revolution per minute. Note 
that the steam is admitted directly through pipe S in the trunnion 
Ti, and is distributed by the different lengths of pipe, Ai, A 2, 
usually three, opening at i, |, and f the length of the boiler. In 
order to avoid the possibility of burning the rags, nearly all of 
these boilers are equipped with the Kinne valve. This is a 
sleeve-type valve, situated in the journal at K, and so set that 
steam can enter the distributing pipe only when the pipe is in a 

Fig. 8. 

position below the cooking liquor, as at A 1. However, in many 
rag boilers, steam is introduced directly at the trunnion through 
a perforated plate. Bi and B2 are blow-off pipes, the inlets of 
which are covered by screen S; C indicates V-shaped spikes, to 
keep rags from being rolled into ropes; Mi and Mo are manholes. 
At the end of the cook, the liquor is drained or blown off through 
Bi and B2', it is not profitable to recover the chemicals in it. 

When the cooking operation is finished, the steam is turned off 
and the boiler is stopped, with the valves Bi and Bo at the 
bottom in position to connect with the blow-off pipes; this con- 
nection is made, and the valve is opened. The steam pressure 
blows off the boiling hquor, which carries with it large amounts 
of insoluble material in suspension. When the cook is thoroughly 


blown, the manholes are opened, and the boiler is rotated as long 
as rags fall out readily; then it is brought to a position such that 
the rags may be pulled out by the workmen (using long-handled 
2-prong hooks) into cars or onto the floor, to drain. 

34. A boiler of the same general type, largely used in England 
and Europe, and somewhat on this continent, is the revolving 
spherical boiler shown in Fig. 8. This boiler is set on trunnions, 
and is operated on the same principle as the cylindrical rotary; 
it finds some favor in cooking straw. Its only advantage is that 
higher steam pressures can be carried in it; it also empties a 
little faster than the cylindrical form of boiler, but has less 



Fig. 9. 

The boiler is turned by means of the worm gear and pulley 
mechanism W. Steam enters at S, and is distributed by the 
perforated plate P; lye enters at L, or through the manhole; V is 
an air vent ; /? is a blow-off valve ; A^ is a perforated plate ; and M 
is a manhole, for charging and emptying. 

35. Another cooker that may be of interest is the Mather kier, 
Fig. 9, which is an adoption into paper making from the textile 
industry. It has been applied to the cooking of rags for paper mak- 
ing in England, and the results reported seem to merit attention. 
The results obtained are given in a report by Cross and Bevan. 
"Its dimensions are 8 feet long by 7 feet in diameter, and it is 
adapted to hold two wagons Ai, A 2, of special design, which are 
run into the kier on tracks B. In order, however, to economize 


time, six wagons are employed, four being either filled or washed, 
while the other two contain rags in process of treatment in the 
kier. The cut and dusted rags are delivered automatically from 
a chute, directly into the wagons. The running of the wagons 
into the kier and the closing of the door C occupy only some 2 or 3 
minutes. The door is lifted by means of chain D passing over 
pulley E to chain drum F; the latter is attached to worm and worm 
wheel G, which is operated by hand wheel H. The door slides 
between frames J, which are wedge shaped ; thus the farther the 
door slides down, the tighter the joint between it and the body of 
cooker. As soon as door C is closed, the rags are saturated with 
caustic-soda solution, which is delivered through sprays K, from 
a tank above the kier, and is circulated by means of a centrifugal 
pump L. Steam is turned on until the pressure reaches 10 pounds, 
and the process is continued for from 2 to 3 hours, according to the 
nature of the material. The steam is blown off, which occupies 
about 15 minutes, the door is opened, the wagons are removed, and 
another pair run in, the three latter operations occupying only 
10 minutes. The rags, after being withdrawn from the kier are 
washed by flowing water on the top of the wagons. This kier 
is capable of doing at least 40 tons of rags per week, and it is 
adaptable to all classes of rags. " 

36. Among the advantages claimed for the kier are: (a) A 
notable improvement in the color of the rags, both before and 
after bleaching; (6) economy in washing time; (c) saving in 
steam; {d) improved strength of fiber; and (e) an enormous 
saving in space — one kier doing the work of several boilers. 

37. The possibilities of washing the rag with hot water before 
its removal from the boiler are worth careful thought. This 
procedure results in a brighter-colored stock and a considerable 
saving in washing time in the washing engine, besides making 
use of the heat in the boiler and rags. 

38. Cooking with Lime. — Caustic lime alone is widely used on 
this continent for cooking new, white cuttings. In the mills 
making the highest grades of writing paper, where such grades 
of rags as hoisery clips, white shirt cuttings, etc., are being used, 
the almost universal practice is to employ lime alone for the 
cooking. These rags are alwa.ys clean, and thej^ do not need the 
severe causticizing action of caustic soda, which has a tendency 
to make rag stock yellow. The excellent color produced by 


cooking with lime is another factor determining its use for that 
particular purpose. Lime, also, is the cheapest alkali. The 
usual practice in cooking this grade of rag would be as follows : 

For 5 tons of rags 600 pounds of lime would be used. The pressure 
carried in the boiler would be 30 to 40 pounds, and the cooking time 10 to 
12 hours. 

In using hme there is the question of just what kind of lime 
it should be. Careful thought points to the conclusion that 
there is but one kind of lime, the use of which is admissible, — 
that is a straight calcium lime. In the manufacturing of sulphite 
pulp, a lime containing a high percentage of magnesium is sought 
after and used with good results. For a rag mill no such advan- 
tage holds and the presence of any considerable amount of magne- 
sium makes that part of the lime almost useless for cooking rags. 
Magnesium hydroxide is relatively even more insoluble than 
calcium hydroxide and its action is almost negligible. 

Note. — The time required varies with different lots of rags, according to 
color, dirtiness, etc., and must be determined by experience. Cooking too 
long wastes time, steam and sometimes fiber. Too short a cook means 
more trouble in washing, excessive bleach consumption, and probably a 
harsh stock for the beater. 

39. Cooking with Lime and Soda Ash. — The next general 
class of rags to be considered includes new cuttings of unbleached 
or colored material such as blue overall cuttings, unbleached 
shoe cuttings, shirt cuttings, etc. For cooking this type of rag, 
a combination of lime and soda ash is generally used. When 
cooking these rags, it is advisable to keep the chemicals fairly 
high, to take care of the fragments of cotton seed hull, so often 
found. The paper maker calls them "shives," and they must 
be thoroughly cooked to prevent their appearance in the finished 
sheet of paper. The usual treatment of this type of rag is about 
as follows: 

For 5 tons of rags, use 1000 or 1200 pounds of lime and 300 to 400 pounds 
of soda ash. The pressure would be carried at 30 to 40 pounds, and the 
cooking time would be about 15 hours. 

40. Cooking Old Whites. — Old rags are divided roughly into 
two types or classes; one of which is the type known as old 
whites. This class would include the No. 1 whites, the No. 2 
whites, and the street-soiled whites. There is some variation in 
the general practice with regard to these rags. Many of the 


mills use lime alone on the better grades, while others use a 
combination of lime and soda ash. An average procedure might 
be this: 

For 5 tons of rags, use 600 pounds of lime and 50 pounds of soda ash; 
cook at 25 pounds pressure for 12 hours. 

This rag has usually been washed many times before it comes 
to the paper mill, and, as a result, the natural waxes and resins 
of the fiber have already been pretty well removed. The purpose 
of the cooking, then, is to remove the oils, grease and dirt that 
may be present. This being the case, it would seem that the 
addition of a small amount of soda ash to the cooking liquor would 
perhaps be the better practice. 

41. Cooking White and Colored Cotton Mixtures. — The other 
class of old rags is that in which there is a mixture of white and 
colored cottons, as twos and blues, thirds and blues, etc. 

In cooking this type of rag, both lime and soda ash are used. 
The lime helps materially in producing a good white, and the 
soda ash is needed to bring up the causticity of the cooking 
liquor to a point where it will more efficiently attack the dirt and 
grease present. The usual treatment for this type would be as 
follows : 

For 5 tons of rags, use 1200 pounds of Ume and about 150 pounds of soda 
ash. Cook at 25 to 30 pounds pressure for 12 to 15 hours. 

42. Cooking Linens. — In the cooking of linen rags, as in the 
case of cotton, no general rule can be laid down, as very much 
depends on the particular character of rags to be cooked. The 
cooking liquor is either caustic soda or a combination of soda 
ash and lime. For a new, white linen, free from shives, the 
cooking treatment is rather mild; 2% of caustic soda, with 
a pressure of about 20 pounds for 6 hours, would cook the rags 

For old linens or new gray linens, which are quite likely to 
contain shives, a fairly strong liquor of lime and soda ash 
is needed. Here the pressure would be advanced to 30 to 35 
pounds, and the time to 10 or 12 hours. 

Note. — Linen is composed of the bast fibers of the flax plant, 
Linum usitatissimum. The plant yields about 8 % of fiber, which is sepa- 
rated by retting and is then known as flax. The ultimate fibers are 6 to 
60 mm. long, and are 0.012 to 0.026 mm. wide, the average ratio of length to 


width being about 1200:1. The fibers are thin-walled tubes, with thickened 
places or knots at intervals; the ends are tapered, the walls rather trans- 
parent, and the canal is small. Two samples of Belgian flax have been 
found to contain 81.99% and 70.55% cellulose. 

43. Use of Caustic Soda. — In England and on the continent 
of Europe, caustic soda is largel}' used in cooking all grades of 
rags, lime being recommended onlj^ for the very cheapest. 
The amount of caustic soda used varies from 1% to 4% or 5% of 
the weight of the rags, depending, of course, on the nature of the 
rags to be cooked. It is well adapted for rags containing albu- 
minous and starch sizings, and it readily attacks oil, grease and 
dirt. The rags are easily washed, and they make excellent rag 
pulp. It is generally recognized, however, that cooking with 
lime will give a pulp of better color. If the question of cost is to 
be considered, lime is cheaper b}' far than the caustic soda. 

44. Variations in Cooking Practice. — To date, there is no 
definite evidence as to the comparative strengths of rags cooked 
with lime as against those cooked with caustic soda. The 
fact that both processes are in excellent repute leads to the belief 
that no great difference will be found one way or the other. 
There is considerable variation in practice among the different 
mills with regard to the cooking pressure and the duration of 
the cook. In some mills, the practice is to cook at a high pressure 
and for a short length of time, while in others, this practice is 
reversed. It is very seldom necessary to exceed a pressure of 40 
pounds or a cooking time of 18 hours. 

Whatever the practice of the particular mill, it is generalh- 
agreed that rags should be thoroughly cooked. Well-cooked 
rags wash easil}', bleach easily, and produce a whiter pulp. 
They respond better to treatment, and produce better and more 
nearly uniform paper. It is a mistake to undercook rags, with 
the idea that the}- will produce a stronger or more durable paper. 


45. The Washing Engine. — Fig. 10 is a plan and longitudinal 
section typical of the Hollander type of washing engine, which 
is most common. It consists of an open tub A, in which the rags 
and water circulate. The circulation is maintained by the roll R, 
which throws the rags over the back-fall B. In front of the roll, 




shown in section, is the button catcher C; this is a recess in the 
floor, covered by a metal grid, and its purpose is to catch any 
buttons, metal, sand, etc. that may still be in the stock. In 
many cases, a second button catcher is installed just behind the 
back-fall. The roll, or fly, bars J are set about 3 inches apart in 
notches in the circumferences of three disks, keyed to shaft S, and 
the spaces are filled with wedges of wood. The bed plate P is made 
up of metal bars interspaced with wood. For a washing engine, 

Fig. 10. 

bed plate should be of the type that the paper maker calls a slow 
the plate, say \ or y\ inch bars and \ or yV inch wood. The 
roll, making 90 to 100 r.p.m., or even 120 r.p.m., draws the 
rags over this bed plate and draws them out; i.e., unravels the 
weave. At some point like V (shown in the plan) is a valve for 
dumping the washer. L, L, are the lighter-bars (levers), on which 
the roll bearings rest, and by means of which the roll is raised 
or lowered through the action of a worm gear and screw, described 
in detail in the Section on Beating and Refining. A hydrant, 
situated at H, is the means of furnishing water to the washer. 
For washing oily rags, where much foam is produced, the foam 
may be skimmed off by a strainer of coarse-mesh wire M, which 


allows the foamy water on top to pass out the outlet N, retaining 
the rags. W is the washing cylinder described in Art. 46. 

46. Fig. 11 shows the principle and construction of a washing 
cylinder. Two octagonal wooden heads Ai and A 2 are carried 
by the shaft B; Ai is fastened to the shaft by a spider, which 
gives an outlet through the sleeve C. Both heads arc slotted 
radially, as at D, from the center to each vertex (corner), and 
also from each vertex perpendicular to these slots, as at E. 
Boards F are slipped into slots D, meeting at the center, and 
ending flush with slots E. Boards G fit slots E, and are planed 
at the edge flush with the sides of the octagons, leaving a space 

Fig. 11. 

H for water to enter as the drum turns. A fillet K deflects the 
water to the outlet C as each pocket rises. Wooden gratings, 
covered with copper or bronze wire screen of 50-60 mesh, are 
screwed to the heads and complete the cylinder; the screen 
prevents much loss of fiber, though some short ones get through. 
The cylinder W (Fig. 10, which also see) turns at the rate of 
about 12 r.p.m., being lowered by a ratchet so that a gear E on 
shaft /^engages a pinion K made fast to a pulley D, which is driven 
by a belt from the roll spindle *S. A washing engine may carry 
from one to four of these drums, as may be necessary. 

Another type of washing apparatus is shown in the Section on 
the Treatment of Waste Papers. 

47. After the rags leave the boiler, they are usually allowed 
to stand in the cars for 24 hours. Evidence has shown 
that by standing in this wa}^, the dirt is more readily washed 
out, and a better color is obtained on the half-stuff. Before the 
rags are furnished to the washer, some sort of a foam killer 
should be added, especially in the case of rags cooked with soda 
ash or caustic soda. A pint of kerosene oil to each 300 


pounds of rags is as effective as most of the prepared or patented 
foam killers. 

48. The Washing Process. — The washing engine is partly 
filled with water, the roll taken up well off the bed plate, and the 
rags furnished, meanwhile adding water gradually. Soon after 
the furnishing is completed, the washing cylinder is let down, 
and the hydrant valve is so regulated as to give all the water the 
cylinder can take out. For the first hour, the engine should 
have plenty of water, and the roll should be kept well off the 
plate, so that it is just brushing the rags. Putting the roll down 
too soon will rub the dirt into the fibers, and the result will be 
poor color. After an hour's washing, the color will usually be 
such that the washerman can begin to bring down his roll and 
take the fiber out of the rags. This must be a slow process, and 
the roll should be lowered gradually and often instead of vice versa. 
As the washing progresses, the amount of wash water may be 
reduced, especially if it is necessary to supply a maximum to 
another washer that has just been furnished. The rags are 
washed until the effluent is practically clear, and until the fibers 
are well drawn out of the rags. Care must be taken not to cut 
the fibers, for long half-stuff is much better than short half -stuff ; 
the beaters can shorten the fibers, but can't make them longer. 

49. Discussion of Washing. — An important consideration in 
the paper-making process is the water. Cellulose readily absorbs 
organic coloring material from it, and becomes yellowish; iron 
is sure to cause discoloration in white or delicately tinted papers. 
One hundred gallons a minute is a very reasonable amount to 
use in a thousand-pound washing engine. This means a lot of 
water; and if organic coloring materials are present in quantity, 
there is a marked effect on the color of the half-stuff. Clean, 
colorless water is a necessity where fine papers are made. 

The time given for washing the various grades or classes of 
rags runs from 5^ or 6 hours to perhaps 14 hours, in a few extreme 
cases. In the case of linens, white shirt cuts, hoisery, etc., the 
length of treatment is determined by the time needed properly 
to draw out the fiber; 8 to 12 hours covers the range in this class. 
For such rags as overall cuttings and the like, 8 hours is a fair 
length of time. In the case of old rags, the time needed to wash 
them clean is an important factor. For thirds and blues, hours 
is the usual time. 


In all the above cases one hour is allowed for bleaching after 
the washing itself is finished, and bleaching is the next subject 
to be considered here. 


(1) Name the three kinds of Hquor used for cooking rags, and give the 
molecular formulas of the chemicals in each. 

(2) Mention an advantage and disadvantage of each kind of cooking 

(3) How is cooking liquor prepared? 

(4) What kinds of rags are best cooked with (a) lime? (h) lime and soda 
ash? (c) caustic soda? 

(5) Why should rags be thoroughly cooked? 

(6) (a) What are the principal features of the washing engine? (6) State 
the function of each. 



50. Theory of Bleaching. — In the process of bleaching, the 
impurities that cover up the natural whiteness of the cotton fiber 
are oxidized and removed; the fiber itself will stand the action of 
reasonable bleaching without being impaired. 

While there are many possible bleaching agents, chlorine or a 
chlorine salt is the most economical, and is the one generally 
used. The bleaching, or oxidizing, is not due primarily to the 
action of the chlorine, but rather to the fact that the chlorine 
reacts with water, liberating oxygen. This oxygen attacks and 
destroys nearly all coloring materials and impurities, changing 
them to colorless or soluble substances, and restores to the cellu- 
lose its natural color. A slight yellow color can be compensated 
for by proper dye-stuffs. Taking, for example, the case of bleach- 
ing powder, which is most used, this reacts somewhat as follows • 
(See Sections on Elements of Chemistry, Vol. II, and Bleaching of 
Pulp, Vol. Ill): In solution in water, 

2CaCl(OCl)-^Ca(OCl)2 + CaCla; 

Ca(0Cl)2 + 2H20-^Ca(OH)2 + 2HC10, 
2HC10->2HC1 + 20(nascent), 
Ca(0H)2 + 2HCl->CaCl2 + 2H2O. 


The final products of the bleaching powder are, then, calcium 
chloride and oxygen in the nascent state. The oxygen unites 
with the impurities to form less objectionable compounds. The 
action of liquid chlorine is very much the same ; the final products 
being oxygen and hydrochloric acid. The intermediate reaction 

H2O + CI2 = HCl + HCIO. 

Soda ash is usually added to neutralize the hydrochloric acid so 
formed, giving NaCl and H2O and CO2. It is to be noted that 
acids are injurious to the fiber, and that they affect some coloring 

51. To get the largest yields in the preparation of bleach liquor 
from bleaching powder, special care must be given to the process. 
Yields of 85 % to 95 % of the actual available chlorine present are 
possible, but yields of 60% to 80% are, unfortunately, rather 
common. One of the first things to determine is the strength 
to which the liquor shall be made up. A few minutes thought 
will prove that the lower the Baume test of the liquor the more 
water may be used in washing the sludge and the higher will 
be the yield. On the other hand, the Baume test must not be 
run too low, because of the greatly increased storage facilities 
needed. A liquor testing 4° Baume is perhaps the most econom- 
ical. The sludge remaining in the settling tank should always 
be washed once, perhaps twice; the latter is usually possible 
only when the liquor that results from the second washing can 
be used with new bleaching powder, to prepare the strong liquor. 

52. Preparation of Bleach Liquor. — The method of preparation 

of bleach hquor is briefly as follows : 

The powder and either wash water or fresh water are put into 
a tank having a mechanical agitator, like an ice-cream freezer, 
or like the vertical stuff chest shown in the section on Beating and 
Refining. The whole is mixed, and the lumps are thoroughly 
broken down. This mixture is then pumped to the settling tank, 
where as much w^ater as is needed is added. The minimum 
settling time for reasonable yields is 24 hours, and wherever 
possible, 48 hours should be allowed. This liquor may then be 
run off from the sludge into the storage tank, using either wash 
liquor or water, as the case may be, to bring it to the required 
degree Baurn^, i.e. the desired chlorine content. 


Extreme care must always be taken to see that the liquor in 
the storage tank is clear, which means that a high calcium lime 
should be used for making the bleaching powder. A bleach 
liquor that is turbid, due to carelessness in running from the 
settling tank, will lose much of its action in the washer. 

53. The Bleaching Process. — Before adding the bleach Hquor 
to the washing engine, the roll should be taken up off the plate, 
the wash water turned off, the excess water removed, and the 
washing cylinder raised. The bleaching liquor may then be 
slowly added. The usual practice in American mills is to add 
an acid substance as an accelerator, after the bleaching liquor is 
in; this must be done with great care. A few pounds of alum to 
each washer makes a very good accelerator, and is safer than acids, 
such as acetic acid, but especially HCl and H2SO4. It assists in 
converting the Ca(0Cl)2 to HCIO. The use of an antichlor 
is common in neutralizing occasional excess of bleach; but it 
cannot be unqualifiedly recommended, because, in most cases, 
the cure is as bad as the disease. Sodium hyposulphite, sodium 
sulphite, and calcium sulphite have all been used, usually in the 
beater, and many others have been suggested and tried. The 
use of antichlor, however, is becoming more and more the excep- 
tion in the bleaching of rags. The bleaching may also be 
hastened by warming the stock. This may be done by blowing 
in steam before adding the bleach; the temperature should not 
exceed 100°F. 

After the rags have been brought to color, the excess chlorine 
should be washed out by lowering the washing cylinder and 
turning in fresh water. A very slight excess may be left to 
spend itself in the drainer. 

There is a further method of washing the excess chlorine from 
the rags, which gives excellent results. When the bleaching is 
nearly complete, the rags are dropped into the drainer. After 
the drainer is filled, 12 hours is allowed for the rags to come up to 
color. At that time, two or three washers of water are put down 
on the drainer of half stock. ^ This process is repeated 12 hours 
later. In this way, practically all traces of chlorine are removed. 

54. Use of Liquid Chlorine. — During the last few years, the 

use of liquid chlorine for bleaching rags has been demonstrated 

as a commercial possibility; and it now seems likely that within 

1 Half stock or half-stuff is defibered raw material that is ready for the 
beater. See Art. 27. 




the next five years its use will become quite general, since it is 
both convenient and more economical than bleaching powder. 

The only apparatus required in order to use it is that for trans- 
ferring it and measuring it into the washing engine. A scale 

Chfck Va»ve 

Compression f hambcr ' 
VacuunA Relief Line- 
Solution Back Pressure Gauge 
Manometer For Soltition Meter- 
Solution Control Valve-^^ 

Solution Line To Bleaching Tanks 
Chlorine Back Pressui-e Gaugr 
Chlorine Control \ alve 
Manonictor For Chlorine Meter 
Chloiine Shut Off Valve 

Chlorine Blow Off Line--- --■ 

Steani Exhaust Line — --• 

Chloi'ine Prcssui'c Reducing Valve 
iTank Pressure Cau^c 

I "Water Pressure Redxieing V^ahe 

■- Stiaincr 

Chlorine Cylindci's 
^--Cold Water Supply Line 
^ Blo-H'cr 


Thermostat - 
Automatic Steam Valvc^ 

Waste Line 

Steani Supply Line ' 

Steam Control Valve IbManifold 
<^irculaiin^ Pipe 
Evapoi-ator Tank 
Steam Shut Off Valve 

for weighing the container, and an injector, accomplishes this 
readily. Fig. 12 shows a diagram of a typical installation. 

55. In using liquid chlorine it has been found that the white 
produced on the half-stuff has a slightly reddish tinge, which 
replaces the shghtly yellowish tinge that is produced with bleach- 
ing powder. This, however, can be easily corrected in coloring. 


Soda ash is generally added, to neutralize the HCl formed in the 
bleaching reaction; otherwise, the acid would attack the fiber, 
the steel of the beater roll, and the paper machine. Experience 
has shown that a pound of chlorine gas will do the work of about 
10 pounds of bleaching powder, which may be figured roughly 
as one-third chlorine; it is always ready for use, and no mixing 
and settling tanks are required. 

56. Amount of Bleach Needed. — The amount of bleaching 
powder required in bleaching rags naturally varies considerably, 
both with the color of the rag before bleaching and the color to 
which it is desired to bring the rag half stock. For new white 
cuttings, the amount of bleach used is about 1%, or 10 pounds of 
bleaching powder in solution for a thousand-pound washer. At 
the other extreme, for such rags as Thirds and Blues, from 5% 
to 6% of bleaching powder is generally used. 


57. The Drainer. — When the half-stuff in the washing engine 
has come up to color and the chlorine is washed out, the valve 











Fig. 13. 

in the bottom of the engine is lifted and the last of the material 
is raked down to the valve, whence it flows into the drainer 
through a system of pipes and valves. Fig. 13. Di, D^, etc. are 
drainers. The stock comes down in pipe P. To fill any drainer, 
as 7)0, all preceding side pipes. Pi, etc., are closed by valves Gi, 




etc.; Go is opened and the main pipe closed as at iv>, preventing 
stock for drainer Do from filling the remainder of P and later 
passing to another drainer. The pipe line is often a plain wood 
box. Sometimes the gates Gi, G2, etc. arc hung so as to swing 
across either the main channel P or the side channels, Pi, P2, etc., 
thus eliminating gates Ki, K2, etc. 

The purpose of the drainers is well expressed in the name; i.e., 
they allow the water to drain from the stock and to take solul)le 
impurities with it. In addition 



■^ s\\S\\\i^yk\\NK\\N\\\^\^^^^ ^ 


Fig. 14. 

to this, the drainer also provides 
for rag half-stuff, storage suf- 
ficient to take care of the 
necessary' variation between the 
consumption and production. 

The drainer is a small room, 
which may be 20 feet long by 8 
to 10 feet wide, and about as 
high. It is of masonry con- 
struction throughout, except 
for a wooden door A (Fig. 
14). This door is an opening 
in the front of the drainer ; it is 
about 3 feet square, and about 
3 feet from the floor. Fig. 14 
shows how the floor of the 
drainer is constructed. When the special tile (perforated with 
holes wider at the bottom) is used, the false floor is laid on con- 
crete, with a slight slope to a main drain. 

58. Time that Stock Is in Drainer, — Rag stock should usually 
be left in the drainers for two to three weeks for best results. 
It is possible to use the stock in a shorter time, and, in the excep- 
tional case, stock may stay in the drainer for several months. In 
the latter case, however, it is usually advisable to freshen the 
stock by letting a washer of water and })leaching liquor down on 
top of it. This helps materialh' in the subsequent use of the 

The possibilities of washing the stock in the drainer by putting 
down washers of water on it, have been discussed full}- above, 
and the subject need not be given further consideration here. 
Care must be taken that as each kind of stock comes through 
from the boiler, a drainer is empty and clean, ready for it. 


59. Possible Use of Wet Machine. — It has often seemed that 
it might be possible to adapt a wet machine (used for de-watering 
wood pulp, as described in the Section on Treatment of Pulp) to 
this problem of draining rag half-stuff. If this could be accom- 
plished, many advantages would be gained. The half-stuff 
could be taken from the machine in laps of uniform moisture 
content, and the question of weight on rag half-stuff (a rather 
dubious figure in most mills) could be settled. The rags might 

Fig. 15 

be piled directly on skids, and these, wrapped if necessary, could 
be put in storage, in the same manner as pulp. The writer feels 
that this method would keep out much of the foreign dirt that is 
occasioned by handling the stock from the drainers to the beaters 
in stock cars. In addition to this, a much more rigid inspection 
of the product would be possible, since many of the troubles 
would show up at once on the wet machine and not at the end 
of the paper machine. 

Fig. 15 illustrates a wet machine. The thin stock enters 
the vat 1, through pipe 25; 26 is a washout. The cylinder 5 
collects fibers from the stock as water passes through the screen 
surface of the cylinder and out at 3 and 4. An endless woollen 


felt, pressed down by the couch roll 2, takes the layer of fiber from 
the cylinder, carries it over the suction box 11 and between the 
press rolls 18 and 19; it winds up on 18, is cut off when 
the layer is right thickness, and is folded into a bundle or lap on 
table 21. Pressure on roll 18 is adjusted by two mechanisms 
15, 16, 17. The felt is carried on rolls 6, 7, 8, 9, 10, 13, and 14, 
and is washed by a shower and whipper 12. A lap from a 72-inch 
machine will weigh about 50 lb., and will contain about 30% to 
35% of fiber. 

The practical questions are of course whether the long rag 
half-stuff could be handled by a wet machine satisfactorily, 
and whether the full bleaching effect of the chlorine would be 
obtained in the shorter time of contact. 


60. Total Losses. — In each step in the preparation of rag 
fibers, there is an attendant loss in weight. Roughly the weight 
of half-stuff will run from 65% to 80% of the weight of raw 
material purchased, depending of course on the grade of rags in 
question and the care used in the processes of treatment. There 
is also a considerable loss in weight in storing rags. Rags in 
storage for several months will lose up to 4% in weight. This is 
almost entirely a moisture loss, and it is probably fully regained 
in the processing. 

61. Losses in Detail. — The first actual loss comes in the 
removing of the tare (wrapping). Under trade customs, this is 
limited to 3%, and, usually, it will not average quite as high as 
this. Any tare in excess of 3% is chargeable to the dealer from 
whom the rags were purchased. 

62. There is some loss in the rag thrasher. In the case of new 
cuttings, this would probably be very slight — not over 5%. 
On street or dump rags, however, losses here amounting to as 
high as 10% or more are not unusual. In the case of cleanly 
packed Thirds and Blues, the loss here will usually be close to 
2%. The dust from the thrashers consists of dirt, buttons, etc., 
with considerable fiber dust, which is thrashed out. Such dust 
is salable to roofing mills and to mills making some of the lower 
grades of coarse papers; it is usually called a No. 2 dust. 


63. The next loss to be considered is the sorting loss. This, 
too, depends very largely on the grade of rags being sorted. 
New cuttings may run as low as 1 % or 2 % ; while in the case of 
old rags, this loss will run from 5% up, depending on the quality 
of the rags. In the case of thirds and blues, from 5% to 6% is 
about the loss to be expected where the best rag obtainable is 
used. The out-throws are largely what is known as jnuss. 
This consists of stoppings, seams, etc., in short, such material 
as must be thrown out of the rags being sorted; it contains 
metal and rubber in abundance. Material that is sorted out 
because of its color goes into what is known as blacks, and this 
consists of hard or fast colors (as red and yellow) and blacks. 
As in the case of the dust, this material is readily salable to lower 
grade mills, and is used in the manufacture of certain of the 
cheaper grades of coarse papers and roofing papers. 

64. There is a further loss at the rag cutter, which is practically 
constant, regardless of the grade of rags being cut; it is due to the 
dust formed by the cutter knives, which is separated from the 
rags by the dusters at that point. The loss in dust at this point 
will run from 1 % to l^i%, depending somewhat on the equipment 
used. This form of dust is called No. 1 dust; it is much superior 
to No. 2 dust, being fairly clean and consisting largely of short 

65. In determining the losses due to cooking, washing, and 
bleaching, these three processes are usually linked together, 
because of the difficulty of arriving at the weight and consequent 
losses at any intermediate step. Moreover, these yields are 
always rather difficult to determine accurately, even though one 
considers the three processes together; for the rag that is once 
wet in the bleach boiler is not dried out again until it gets into 
paper. At their best, then, these figures are not any too accurate. 

66. In the case of new cuttings, a yield of 85%, based on the 
weight of the dressed rags, is a figure that is fairly accurate. 
This figure would of course be too high in cases where the rags 
were heavily loaded with starch or other material. 

In the case of such rags as thirds and blues, a yield of 75% to 
80%, based on the dressed weight of the rags, is about what 
should be expected. For street whites, however, this yield 
would be considerably lower, and would be nearer 60% than 


Many things may come into individual lots or types of rags 
that would change these yields entirely. For the general run 
of rags, however, they should prove out fairly accurate. 


(1) (a) What bleaching agent is generally used for rags? (6) how does 
it act? 

(2) How can an excess of bleach be gotten rid of? 

(3) As regards purpose and manipulation, compare the drainer with 
the wet machine. 




67. Use and Importance. — By far the most important of the 
hemp fibers used for paper making is the inanila hemp. This 
fiber is used very largely by a group of mills known as makers of 
rope papers. 

The largest tonnage of these papers goes into sacks, the first in 
importance being flour sacks, but also including sacks for sundry 
uses, such as cement, lime, plaster, etc. The manila-rope fiber 
is used on account of its great fiber strength; also, for the pliability 
of the product which it produces. 

Manila-rope papers used for cable insulation purposes probably 
rank next in importance. The copper conductors in power 
cables are insulated by a number of wraps of rope paper, slit 
in widths from | inch to 2 inches, after which, the whole cable is 
saturated with insulating oil compounds. In telephone cables, 
the fine conductors are insulated with a single thickness of very 
thin manila paper, which is left dry in the final cable. Other 
uses of manila paper are for sand paper, shipping tags, gaskets, 
pattern paper, and the like. 

Note. — Hemp (Cannabis sativa). The fiber is prepared by retting, from 
filaments that run the entire length of the stem. The ultimate fibers 
composing these filaments vary from 5 to 55 mm. in length, averaging 22 mm. 
in length and 0.022 in diameter. The ratio of length to diameter is, there- 


fore, about 1000:1. The fibers have very thick walls, which are not very 
highly lignified. The ends are large and sometimes flattened, and the central 
canal is almost obliterated. In microscopic appearance, the fibers are very 
similar to those of flax; but they differ from linen in having greater ability 
to break down into fibrilke (fibrils) during the mechanical process of paper 
making. Miiller gives the cellulose content of a sample of raw Italian hemp 
as 77.13%. Many other plants yield fibers to which the name hemp is 
given; but they are generally distinguished as manila hemp, sisal hemp, sunn 
hemp, etc. 

Manila hemp (Musa textilis). Manila hemp is prepared from the outer 
sheath of the stems of the musa, which is a species of banana. The ultimate 
fibers are from 3 to 12 mm. long, averaging about 6 mm. The width varies 
from 0.016 to 0.032 mm., averaging 0.024 mm., the ratio of length to width 
being about 250:1. The fibers taper very gradually toward the ends; the 
central canal is large and very prominent, while fine cross markings are 
numerous. The percentage of cellulose in raw manila is given by Miiller 
as 64.07 %. 

Agave. Among the most common of the fibers of this class is sisal hemp, 
or heniquen, which is largely employed for cordage, bags, etc., in which forms 
it reaches the paper mill. The ultimate fibers are longer than manila fibers, 
rather smaller in diameter, tapering and pointed at the ends, and compara- 
tively stiff. The central canal is not prominent, but can be seen as a narrow 
line in some of the fibers. The walls are thick; they are characterized by 
many fine cross lines, close together, which are found on nearly every 

68. Source of Supply. — The manila fiber used in these papers 
is practically confined to old manila rope. The old rope is 
collected by junk dealers, usually sold by them to larger dealers, 
who, in turn, sell it to the rope-paper mills. Such old rope is 
usually collected at definite places; such as sea ports, important 
lake or inland shipping points, gas- and oil-well districts, etc. 
A very considerable amount of old rope for paper making pur- 
poses is imported into this country from European points. The 
manila fiber for rope making comes from the Philippines, and it 
represents one of the principal products of these Islands. 

69. Preliminary Treatment. — The rope is inspected, first, on 
being unloaded and, again, and more intimately, at the rope 
cutters, where any foreign material or fibers other than manila 
are thrown out. The rope is cut by what is known in the trade 
as rag cutters, but the knife equipment of these is so modified as 
to produce longer pieces. The length of the manila threads after 
passing through the rope cutter ought to be about 2 inches. 
The cut rope then goes through rotary dusters, which open up 
the fibers and eliminate much of the loose dirt. 


70. Cooking. — From the dusters, the cut rope is then fed into 
the rotary boiler. This is the same type of boiler as is in general 
use for cooking rags, and it holds approximately 5 tons. The 
cooking liquor is made from lime and soda ash; and, as is the case 
with rags, the strength of the liquor, the time of the cooking, 
and the steam pressure vary with the results to be obtained and 
the characteristics of the particular lot of rope at hand to be 
cooked. Average conditions would be about as follows: 

For a 5-ton boiler, use 1000 pounds of lime and 500 pounds of soda ash; 
cook at 25 pounds pressure for 10 hours. 

This cooking process removes the natural waxes and loosens 
up the foreign dirt and grease. It makes the fiber softer and 
more pliable, and greatly improves its working qualities. 

71. Washing and Bleaching. — The washing and bleaching are 

usually done in the beater, that is, as different parts of the beating 
process, without recourse to the half-stuff, or ordinary, method of 
treatment. The rope-paper mills generally use beaters of from 
800 to 1300 pounds capacity. Ordinarily, the cooked fiber is 
furnished directly to the beater; and the washing cylinder is 
lowered and the washing process is carried out in much, the same 
manner as rags are washed in the washing engine. When the 
washing is completed, the bleach is added. After bleaching, 
the washing cylinder is again lowered, and the excess of bleach is 
washed out. From this point, the ordinary beating process is 
continued. The amount of bleach is quite low, as a pure white 
is not attainable and is never attempted. Moreover, a great 
many of the papers are entirely unbleached; but if bleached, the 
usual quantity of bleaching powder consumed is from 5% to 
10% of the weight of rope furnished. 

72. Yield. — The yield of manila rope as bought, compared with 
the amount of paper made, will run about 50% to 65%, depend- 
ing on the thoroughness of the cleaning, cooking, and bleaching 
treatments. It can be readily seen that a satisfactory paper for 
cement sacks can be produced with much less cleaning than is 
required for a light-weight, telephone insulating paper. 

Mention should be made here of the use of true hemps, which 
are employed in Europe for certain special papers, such as 
Bible, cigarette, etc. The true hemp is prepared by methods 
described; but in the beater, it acts like linen, the fiber splitting 


longitudinally into fibrils which can be felted into a sheet possessing 
exceptional formation, strength, opacity, and finish. This fiber 
bleaches to a much better color than manila hemp. 


73. Use and Importance. — The jute fiber is the isolated bast of 
the jute plant, which is an annual of very rapid growth, attaining 
a height of 8 to 10 feet in the hot Indian climate. To obtain the 
bast fiber, the plants are cut down and steeped or retted in a pool 
of stagnant water. By this means, a fermentation process is 
started. Wlien the retting is completed, the bast layer (which 
is between the bark and the wood) is stripped off and washed, 
and goes in this form to the textile mill, where the fiber is spun 
and woven into twine or burlap. 

Jute fiber is extensively used in the manufacture of wrapping 
paper; it produces paper of excellent strength and durability, 
being second only to hemp. Attention must be called at this 
point to the fact that jute is not a pure cellulose fiber, being what 
is termed a ligno-cellulose, and it is used as such in paper making. 
On this account it bleaches to a bright yellow color, and this, of 
course, places certain limitations upon its use. The fiber is also 
used to some extent in buff drawing paper and other papers of 
that type. 

74. Source of Supply.— As is the case with cotton, the raw fiber 
is much too high in price to permit of its direct use by the paper 
maker. Moreover jute cloth goes almost exclusively into sacks 
and other articles, which are cut without waste, so that now 
cuttings of jute are not on the market. This limits the supplj' of 
the paper maker to old sacking, burlap, and string, and practically 
all of the jute used is from this source. As is the case with rags, 
it is collected and sorted and turned over to the paper maker in 

The fiber from the butt of the jute plant is not suited to spin- 
ning; and a few years ago, these jute butts were used to a con- 
siderable extent by paper makers. Thjs stock is very dirty and 
not particularly desirable, and its use is considerably restricted. 

Note. — Jute \Corchorus cap.mlaris and C. olitorius) . The fibers of j ute are 
about 2 mm. long and 0.022 mm. in diameter. They are thick-walled; the 
central canal is very variable, at times being of considerable width and then 


narrowing to luirdlj' more than a line. The surface is quite smooth, and 
there may be noted at intervals radial canals and joints, which are similar 
to those in linen, though not so pronounced. Jute contains about 63% 
cellulose and 24% ligno-collulose. As exported, the composition of the 
bast varies, the fiber content ranging from 49% to 59%. 

75. Preliminary Treatment. — The preparation of jute for paper 
making varies considerably with the particular type of paper that 
is to be made from it. Obviously, in the case of a high-grade 
drawing paper, much more care must be taken in the sorting, 
washing, and bleaching than would be the case when a much 
cheaper product, such as wrapping paper, is to be made. In the 
former case, the jute bagging is put through the thrasher; it is 
then sorted over rapidly by women, who take out the foreign 
material that may be present and any pieces of rotted bagging. 
The stock is then ready for the cutter, where it is cut, dusted, and 
delivered to the boiler for cooking. The ordinary type of rag 
cutter and duster is used, and the boiler is the cj-hndrical rotary, 
in nearly all cases. 

76. Cooking. — The reasons for cooking jute are similar in 
man}' respects to the reasons for cooking rags. The cooking 
removes the foreign dirt and loading and the natural waxes of the 
fiber, leaving it in such condition that it responds readily to sub- 
sequent treatment. In cooking jute, no attempt is made to 
cook out the lignin — the object is simpl}- to prepare a ligno-cellulose 
fiber for use as such in the paper-making process. This being the 
case, it is the practice to use fairl}- low temperatures or pressures, 
sa}', 20 pounds. The cooking time most commonly used is aljout 
10 hours, although this ma}^ be varied 2 hours either way in the 
different mills. 

It is the almost universal practice to use lime as the cooking 
chemical. While the quantity varies somewhat with the con- 
dition of the stock and the result desired, the usual practice is 
to use from 10% to 20% of lime. 

77. Washing and Bleaching. — In general, jute is washed and 
bleached by the same processes as rags. In most cases, however, 
the stage known as half -stuff is omitted, the washing and bleaching 
being done as a part of the beating process. That is, instead of 
dropping the stock into the drainer after it is washed and bleached, 
the beating operation is continued in the same engine, without 
interrupting the process. In this case, the stock is furnished into 


the engine after it has been cooked and is then throughly washed 
with the washing cyhnder. When the washing is complete, the 
bleaching liquor is run in, and the stock is allowed to bleach up to 
the desired color. Dry bleach is often added directly to the 
engine when bleaching jute. It is usual to "sour" with a little 
H2SO4 to hasten the bleaching action; but free chlorine may 
form yellow lignin chloride. The excess bleach is then washed 
out with the cylinder washer; and from this point, the beating 
operation proper begins. 

In bleaching jute, about 8% of bleaching powder, figured on 
the dry weight of the fiber, is used, and the stock comes up a 
bright yellow color. Liquid chlorine cannot be used successfully, 
as the bleaching solution must be alkaline. 

78. Yield. — The yields from the jute fiber vary considerably, 
depending on the care with which the preparation of the fiber is 
conducted and the degree of washing and bleaching. Since the 
half -stuff or intermediate form is usually omitted, it is convenient 
to consider the yield of paper from the baled weight of the jute; 
in the average mill, this yield varies from 50% to 65%. 


79. Cotton-Seed Hulls. — When the cotton seed comes from the 
cotton gin, there is left on it a fuzz of short cotton fibers, firmly 
attached to the seed. This will amount to approximately 200 
pounds of fiber per ton of seed. It has long been the practice to 
cut off from 60 to 75 pounds per ton of seed, as a first cut, for use 
in making mattresses ; the remainder went into the meal used for 
cattle food. As a development of the war, it now seems entirely 
possible that the second cut, hull fiber or linters, from the cotton 
seed may be made available for use in paper making. Little can 
be said as yet about this source of raw material, as the first mills 
for its preparation in quantity are just beginning operation. 
From figures now at hand, several hundred tons per day may 
become available, if the experiment is a success. Just how, when, 
and where the paper maker will use it remains to be seen, and 
much depends on what can be done with it after the preparation 
problem is thoroughly worked out. It now seems likely, how- 
ever, that its place will be as a substitute for soft cotton rags, 
such as thirds and blues. 


80. Preliminary Treatment. — A brief outline of the present 
ideas as to how this material should be handled follows: 

The seed is first thoroughly cleaned and all foreign dirt is 
removed; after which, the first cut is made, say of 75 pounds per 
ton of seed. The seed is then cut, and the kernels are separated 
from the hulls. The latter are treated in a steel attrition mill 
for the removal of the fiber, and the fiber and hull bran are 
separated by proper screening. 

81. Cooking. — The next process is the cooking. The cooking 
liquor used is caustic soda, and a fairly high concentration is 
necessary, say about 20% on the weight of air-dry fiber. Experi- 
ments so far indicate that a high pressure is needed (about 80 to 
100 pounds), and that considerable care must be taken to insure 
proper circulation of the liquor in the boiler. The cooking time 
depends largely upon how rapidly the digester can be brought up 
to temperature, and it will probably be found that 6 to 8 hours 
will be the right length of time. 

Little can be aid as yet with regard to the type of boiler that 
will be used for this work. To date, experiments have been 
largely with the soda-pulp digester. There are two difficulties to 
be overcome with the ordinary soda digester, however; the 
first is that of circulation of the cooking liquor, and the second is 
the difiicult}^ of blowing the cook. Very few of the cooks of this 
material in the usual soda digester will blow clean. 

How the further preparation will be carried out is also rather a 
question. The cooked fiber must be washed and bleached. It 
will probably not be possible to screen it as a part of its prepara- 
tion because of the very nature of the fiber. This makes it all 
the more necessary that it be thoroughly cooked, so that the 
bleaching process may destroy all the seed-hull fragments that 
are left in, and which would make dirt in the paper. Several 
mills are said to be using hull fiber and linters with good results, 
but details of their methods are not available. 

82. Use in Paper Making. — The use of this material on any 
extensive scale in the paper industry depends on two factors: 
first, whether it can be so handled by the paper makers that it 
will produce the same strength, tear, and folding endurance 
that are obtainable with soft rags; second, whether it can be 
profitably produced in competition with soft rags over a period 
of time. 


83. Bagasse. — The crushed stalks of the sugar cane, known as 
bagasse or begass, have been proposed many times as a possible 
souice of paper-making raw material, and this material has been 
tried out on several occasions. It is first run through the cutter, 
and is then cooked with caustic soda. 

The pulp is easily reduced, and is readily washed and bleached. 
The yield of pulp from the dry stalk is very low, from 20 % to 30 %. 
This fact, together with the fact that it is generally rather dirty, 
and that it ma}^ usually be more economically used for fuel on 
the plantation, has made its use very limited. In character- 
istics, it resembles straw pulp rather closely. An interesting use 
of bagasse paper is in covering young plants. The cane, or 
pineapple, pierces the paper, while weeds are smothered, and 
moisture conserved. 

84. Miscellaneous Fibers. — Almost any fibrous raw material 
can be used in the manufacture of paper; consequently, there are 
many other fibers, the preparation of which might be outlined. 
Most of these fibers are seldom, if ever, actually used in making 
paper, however, and the general method of preparation is appli- 
cable to all. First, clean the fiber thoroughly; then cook it with 
an alkali; then wash and bleach it, and it is ready to be made into 
paper. Among others, the following deserve mention; papyrus, 
ramie, China grass. New Zealand flax, saw grass, flax straw and 
the paper mulberry-tree fiber of the Japanese. Corn and cotton 
stalks have also received some attention in the United States; there 
is a possible field of usefulness for them as fillers. Corn stalk 
fibers are very similar to those of bagasse. 

By James Beveridge 


85. History. — Esparto was introduced as a paper-making 
material and as a substitute for rags in 1856 by the late Mr. 
Thos. Routtcop, a North of England paper manufacturer. Since 
then, it has found much favor in England and in other European 
countries, owing to the quality of the fiber it jnelds, which is 
specially suitable for the manufacture of high-class book or 


printing papers and medium-class writing papers. Printing 
papers made from it are of a soft, impressionable nature, yield- 
ing clear impressions from type and blocks. It is largely due 
to this property that the printing and book papers of the highest 
class in England are so distinctive in character. 

86. Where Grown. — The grass occurs in Spain and Northern 
Africa; it resembles in form a stout wire, tapering to a fine point 
at the upper end, and varying in length from 12 to 30 inches. 
Owing to the demand, attempts have been made to cultivate 
it; but it grows wild, covering large areas in close proximity to 
the sea coast, and is somewhat easily obtainable. It is pulled 
(not cut) and harvested by the natives, packed in large pressed 
bales, and shipped in this form. It differs in quality, according 
to locality and selection, its price being regulated accordingly. 
These qualities take the name of the district or Port from whence 
they are shipped, such as Tripoh, Sfax, Oran, Gabes, etc., in 
Northern Africa. The Spanish variety, however, is considered 
the best, although now very limited in quantity, and it commands 
the highest price. This grass is fine, of a bright russet-yellow 
color, free from the green chlorophyl when well matured, and 
yields the highest percentage of fiber. On the other hand, the 
varieties from Northern Africa differ widely. Some are green, 
coarse, and unripe, yielding a lower percentage of fiber, and are 
more difficult to reduce to pulp and to bleach. The additional 
expense incurred in this treatment naturally reacts on their 
market value. From whatever source obtained, it is recognized 
that the fine, well-matured, or ripe grass is more easily reduced 
to fiber than the coarse, green, and unripe variety; in that it 
requires less chemicals and yields more finished paper. Esparto 
should always be kept under cover in a dry place, as it is apt to 
heat and rot, if allowed to get wet. 

Note. — Esparto (Stipa tenacissima and Lygeum spartum). The bast 
fibers are grouped in bundles or filaments, which are resolved into ultimate 
fibers by the chemical processes employed. The fibers are shorter and more 
even than those from straw, averaging about 1.5 mm. in length, and the 
central canal is nearly closed. Serrated cells are numerous, but are consider- 
ably smaller than those from straw, while the smooth, thin-walled 
cells are absent. The chief characteristic that distinguishes esparto from 
straw and other fibers is the presence of small, tear-shaped cells derived from 
the hairs on the surface of the leaves. Cross and Bevan give the following 
as the percentage of cellulose in air-dry esparto: Spanish, 58.0%; Tripoli, 
46.3%; Arzew, 52.0%,; Oran, 45.6%. 


87. Steps of the Process. — The process of reducing it to fiber 
is a simple one, involving four operations, viz: (1) Dusting; (2) 
boiling; (3) washing, pulping, and bleaching; (4) screening and 
making into laps. The equipment employed for these operations 
is: For (1), a willow or duster; for (2), an esparto boiler, specially 
constructed for the purpose; for (3), an ordinary half-stuff or 
a breaking-in engine of the Hollander type, provided with a 
drum washer; and, finally, for (4), screening equipment and 
presse pate machine, for running off the bleached pulp into a 
thick sheet. In place of the Hollander, a pulping machine of 
cylindrical type is sometimes used; and, obviously, the fiber may 
be screened before or after bleaching. 

Fig. 16. 

88. Dusting. — As the bales of esparto are brought into the 
mill, they are opened, and the grass is loosened and fed into the 
hopper A, Fig. 16, of the conical duster or willow. A conical 
screen revolves in a housing B, the sand and dust fall through, 
and the clean grass is discharged at the spout C onto a conveyor, 
which takes it to the loft over the esparto boilers. The paddle 
D keeps the spout clear. In the early days it was deemed neces- 
sary to remove all roots by hand picking, girls being stationed 
alongside the belt conveyor for this purpose ; but as care is now 
taken to avoid pulling the roots while harvesting the grass, this 
precaution is considered unnecessary. The root ends of the 
grass are hard, and those that remain partly untouched by the 
caustic liquor during the cooking are removed by the screens. 
The loss in weight during the dusting varies from 1 % to 6 % ; and 
the grass, after dusting, contains from 2% to 3.5% of mineral 
matter, the bulk of which consists of silica, which is soluble in 
sodium hydrate, and comes away in the black liquor as silicate 
of soda. 




89. Types of Digesters. — A form of digester in wliich the 
boiling takes place is shown in Fig. 17. It consists of an upright 
cylinder M with domed top, and fitted internally with a per- 
forated false bottom B, from the center of which, a vomit pipe C 
receives the hqiior that drains through and carries it upward, to 
pass again through the body of the grass. A steam jet I in the 

Fig. 1 

bottom of this vomit pipe, pointing upward, throws the caustic 
liquor against a dash plate D at the top, which distributes the 
Ij^e over the surface of the grass. The boiler is also provided on 
its side with a circular door H immediatel}^ above the false 
bottom, to enable the workman to remove the cooked fiber, and 
with another door E, on the top crown, for the introduction of 
the grass. K is a safety valve, and F is a fitting for introducing 
cooking Hquor and wash water, if desired. Liquor maj- also 
be run in through the charging hole. 


90. A digester of a newer type, shown in Fig. 18, resembles the 
foregoing in its action. Two internal circulating, or vomit, pipes 
A are provided, one on each side of the vessel; these throw the 

liquor into the upper chambers 
B under the crown, and the 
liquor is then distributed over 
the surface of the grass, as 
shown in the illustration. 
Letters correspond to parts 
described for Fig. 17. Ob- 
viously, in place of the vomit 
pipes, a centrifugal pump may 
be used for circulating the 
liquor; and the boiler and its 
contents maj^ be heated with 
a coil, instead of bj^ injecting 
steam directly into the charge, 
in a manner similar to that 
sometimes employed in cook- 
ing wood pulp. These esparto 
boilers are built to hold from 
2| to 3 tons of grass per charge. 
91. Cooking Liquor. — The 
stem of esparto (and of grasses 
in general) is largely cuto- 
cellulose or pecto-cellulose, 
instead of ligno-cellulose as in 
jute. This must be broken 
up by hydrol3^sis, and the non- 
cellulose substances, fats and 
waxes, rendered soluble. 
Some are changed to acids, 
which unite with the soda; 
others form sugars and other 
soluble substances. 

The resolving fluid used is 
caustic soda (sodium hydrate), 
although the so-called sulphate processes, in which a mixture of 
sodium hydrate and sodium sulphide is used, is equallj' appli- 
cable. The caustic liquor is obtained by causticizing 58% soda 
ash with lime in the usual way (see the Section on Soda Pulp, 

Fig. is. 


Vol. Ill), and the amount of alkali used varies with the quality 
and kind of grass and the treatment. For the finest quality of 
esparto, from 18 to 19 pounds of 58% alkali per 100 pounds of 
grass are enough ; but for the coarsest immature kinds, as much 
as 25 pounds are required. These quantities of alkali, however, 
depend to a certain extent on the steam pressure (or temperature) 
and the time adopted for cooking. When high temperatures 
(or pressures) are used, less alkali is needed. The volume of 
lye used varies within somewhat narrow limits, and would 
depend on the quality of the steam and whether or not the charge 
is heated directly, with injected steam, or indirectly by means 
of a heating coil. As a general rule, it approximates to 95 
cubic feet per 2000 pounds of grass in the former case; and, in 
the case of Spanish esparto, using 18 pounds of alkali per 100 
pounds of grass, it would correspond to a liquor having a specific 
gravity of 1.048, at 62°F. (9.6° Twaddell), and would contain 
total alkali equivalent to 60 grams of soda per liter, of which 
92% to 94% exists as hydrate, the other 8% to 6% being car- 
bonate. When 25 pounds of 58% alkali are used, the liquor 
would have a specific gravity of approximately 1.066, at 62°F. 
(13.2° Tw.) ; it would contain soda equivalent to 84 grams per liter, 
of which from 92% to 94% exists as hydrate. The time required 
for cooking also varies, and depends on the amount of soda and 
the steam pressure or temperature; from 50 to 60 pounds pres- 
sure is common in modern esparto mills. At this pressure the 
average cooking time occupies from 2 to 3 hours. 

92. Cooking Operation. — The following is a representative 
example of a cook in actual practice, in which fine, well matured 
esparto was treated, the amount of alkali required being 18 
pounds (58% alkali) per 100 pounds of grass. 

Esparto (Oran, fine ripe grass) 6000 . lb. 

Caustic liquor, volume 285 . cu. ft. 

Caustic liquor, Sp. Gr. (10°Tw.) 1 . 050 

Caustic liquor, grams 58 % alkali 60 . per liter 

Caustic liquor, grams soda (Na20) 34 . 8 per liter 

Caustic liquor, per cent causticization 92 . per cent 

Time of boiling 2§ hours 

Temperature 298°F. 

Pressure (gauge) 50 lb. 

93. To carry out this cooking operation in practice, the boiler 
is first of all filled with the loose grass, care being taken to 


distribute it uniformly inside. The liquor is then run in, and 
the vomiting is begun. The caustic lye soon softens the esparto, 
causing it to fall and to pack somewhat closely on the perforated 
false bottom. As this takes place, more grass is added until the 
whole charge of 6000 pounds has been introduced. The main 
lid is then securely bolted down and the heating (and vomiting) 
is continued until the pressure reaches 50 pounds. During the 
heating; a little steam is allowed to escape, by means of a small 
valve provided for the purpose, to carry away the air and light 
oils inside. The pressure is maintained for 2| or 2| hours, after 
which it is blown down, the escaping steam being used for heating 
the next charge of caustic liquor, and, also the weak liquor for 
the first and second washings. When the pressure is nil, the 
black liquor is drained off, the hot washings from a previous 
operation are pumped in, and the vomiting is again begun. This 
strong wash liquor is run direct to the soda-recovery house and is 
mixed with the strong black lye. The recover}^ of the alkali in 
black liquors is fully treated in Vol. Ill, Sections 5 and 6. Hot 
water is now added, and the grass is washed a second time, the 
weak liquor from this washing being run off into a tank, to be 
used again as a first washing for the cook. The top manhole lid 
is now removed, and, if necessary, further wash water is added; 
but, as this will contain but a small quantity of soda, it may be 
run to waste. After draining thoroughly, the side door is 
opened, and the boiled grass is removed by hand into galvanized 
iron or wooden box trucks, or is otherwise conveyed, to the 
Hollander or bleaching engine. When properly boiled, the 
strands of grass will easily come apart, or will be broken up into 
pulp; in appearance, the original color of the grass will be 
preserved, but will be brightened. 


94. Operation. — Final washing and bleaching are usually 
carried out in one operation, in a Hollander of large capacity, 
fitted with drum washers, in order to remove the last traces of 
soda and some intercellular matter, which invariably passes 
away with the wash water. The bleach liquor, consisting of a 
solution of calcium hypochlorite Ca(0Cl)2, of a Sp. Gr. of 1.040 
(or 8°Tw.) is then run in. In most cases the temperature is 
also raised to about 100°F., either by washing with hot water or 




by direct heating with injected steam prior to bleaching. In this 

way, the bleaching is hastened. The fiber, after the addition 

of the bleach liquor, quickly changes color, if 

well-matured grass is being treated; but the 

color changes more slowly if the grass is green, 

always assuming that no great excess of 

bleach has been added. The pulp is kept in 

circulation for some hours; it is then dumped 

into a pulp chest, whence it is pumped to the 

screens A, which are usually placed at the 

end of the presse-pate machine, Fig. 19. The 

screened stock passes to the flow box B, 

which delivers it in a quiet, shallow stream, 

over the apron C to the Fourdrinier wire D. 

Rubber deckle straps E prevent escape over 

the edges. Water drains through the wire, 

some is extracted by the suction boxes F, and 

some by the couch press (rolls) G and H. 

The sheet then passes to the felt K, which 

carries it through the press rolls L and M and 

delivers it at iV, to carts or a conveyor. The 

fiber is run off on this machine as a thick web, 

and it is taken to storage or to the beating 

engines for conversion into paper. As a 

general rule, the fiber is bleached before 

screening, as this is considered a simpler 

method than that of screening before 


Consideration should here be given also to 
the wet machine, see Art. 59. 

95. Yield Depends on Quality. — The yield 
of air-dr}' fiber containing 10% moisture, 
from 100 parts of grass, depends very largely 
upon the quality of the esparto. From well- 
matured Spanish and Oran, it does not exceed 
45%, while in the case of the unripe or green 
kind it may be as low as 40 % or even under. 
Not more than 42% maj^ be expected, on an I 
average, from deliveries of North African grass. 

96. The Sulphate Process. — Esparto fiber may also be 
prepared b}^ the sulphate process, with equally good results. 




The manufacturing conditions being very similar to the fore- 
going, as outlined for caustic soda. For details see Section 6, 
Vol. Ill, Manufacture of Sulphate Pulp. The advantages claimed 
for the sulphate method are : (1) A greater yield of bleached fiber; 
(2) a greater preservation of its strength. The treatment as a 
whole is also cheaper, salt cake being used in place of soda ash. 


97. Kinds of Straw Pulp. — There are two kinds of straw pulp 
manufactured, viz.: (1) Yellow pulp, used for the production of 
cheap wrapping papers and straw board; (2) straw cellulose, 
invariably put on the market in the bleached state, which is used 
for making the finest writing papers. 

Note. — Straw. In straw pulp, the bast cells or fibers form the greater 
part of the pulp. These are comparatively short and slender, with sharp 
pointed ends; at quite regular intervals the walls appear to be thickened and 
drawn together to resemble joints. The dimensions of straw fibers vary with 
the kind of straw and with the conditions of growth, nature of soil, etc. 
They are longer than those from esparto, but not so long as the fibers from 
spruce wood, and would compare more nearly with poplar fiber in paper- 
making value. Accompanying the bast fibers in straw pulp are numerous 
epidermal cells from the pithy portion of the stem. (See Fig. 1, Section 1, 
Vol. III.) The latter vary in shape from nearly round to long, oval cells, 
whose length is several times their width. Both types of cell aid materially 
in the identification of straw pulp. 

Straw as used in paper making includes the stems and leaves of the various 
cereals. The composition of straws, particularly with regard to the amount 
of ash and its constituents, varies greatly with the soil upon which they were 
grown. Wolff gives the following analyses for different straws: 



















Fat and wax 

Nitrogenous matter. . . . 
Starch, sugar, gums, etc 

























36.2 1 








See also Lloyd, "The Structure of Cereal Straws," Pulp and Paper 
Magazine of Canada, Vol. xix, pages 953-4, 973-6, 1002-4, 1025-6, 1048-50, 
1071-5 (1921). 


98. Yellow Straw Pulp. — Yellow straw pulp is manufactured 
by boiling the straw under pressure in milk of lime, to which a 
small quantity of soda may be added; and, afterwards, passing it 
through kollergangs and beaters, before finally converting it into 
paper or board. The straw is cut into chaff of about 1 to 1^ 
inches long, thoroughly dusted by passing it through a suitable 
willow, see Fig. 16, and then digested in rotary boilers, preferably 
of the spherical type, Fig. 8, at a pressure of 40 to 50 pounds 
above atmosphere, with 10% of its weight of caustic (quick) 
lime that has been made into a milk with water and then care- 
fully strained, to free it from grit. The volume of liquid used 
should be sufficient to cover the chaff, and the boiling should be 
continued until the particular kind of straw under treatment is 
softened sufficiently to be broken up or pulped in the disinte- 
grator. When the boiling is finished, the straw is washed, and 
is then ground up into pulp in the kollergang or beater. A yield 
of 100 parts of yellow straw pulp requires 133 parts of straw, 
(yield 75%), 13.3 parts of caustic lime, and 20 parts of coal (for 
boiling only). The power required to drive the cutters, digesters, 
kollergangs, beaters, and pumps is approximately 25 h.p. per 
2000 pounds per day. The product is coarse in appearance and 
low in strength. 

99. Straw Cellulose. — The routine of making this product is 
very similar to that for esparto. The straw should be as free 
from weeds as possible, cut into chaff, then dusted (to get rid of 
sand, etc.) and, finally, boiled in a caustic-soda solution. In 
recent years, the sulphate process (see Vol. Ill, Section 6) has 
been used with much success, as it jdelds a cheaper boiling fluid, 
a higher yield of cellulose, and a stronger fiber, without altering 
the mode or routine of manufacture to any great extent. 

100. Kinds of Straws Used. — The straws usually employed are 
wheat, rye, oat, and barley, though flax straw from plant grown 
for linseed, being unsuited for textiles, is being developed as a 
source of paper-making material. The fiber has the character- 
istics of linen; but it requires a drastic preliminary treatment, 
as does straw. It can be bleached to produce a white paper of 
good color and strength. Wheat and rye yield cellulose fibers 
that are closely allied in point of length and strength or felting pro- 
perties; oat, on the other hand, has length, but is of medium felting 
power; while barley straw is short, soft, and of low felting power. 


All these fibers are hard and crisp when bleached and dried, and 
they impart this property to the paper of which they form a part. 

101. Preliminary Treatment. — As a general rule, when these 
four varieties are available, a mixture of all four is used. It is 
essential that they be free from weeds, since it is quite impossible 
to make high-grade, bleached-straw cellulose suitable for high- 
grade writings when weeds are present to any great extent. In 
the best factories, the straw is opened out, or is spread by hand 
onto a wide traveling canvas belt, which leads to the chaff cutter, 
alongside of which, girls are stationed, whose duty is to pick out 
the weeds. The straw is then delivered to the cutter, which cuts 
it into chaff from 1 to 1| inches long. From this, it falls into the 
willow or duster, and is then blown through a galvanized iron 
pipe, into the loft over the digesters. Sometimes it is given 
a preliminary dusting before it enters the chaff cutter, every care 
being exercised to get the chaff as clean as possible. 

102. Cooking Liquor. — The cut straw is then digested in 
rotary digesters, either with caustic soda or with a mixture of 
hydrate and sulphide of soda, as in the sulphate system of 
manufacture. The following figures represent the proportion 
of lye to straw when cooking with caustic soda alone, and, also, 
other conditions of the boiling process, all from actual practice, 
as followed in a Dutch factory : 

Weight of straw (mixture of oat and wheat) = 4480 lb. per boil 
Amount of caustic lye = 1610 gal. (Imperial) 

Time under steam pressure = 4 hours 

Steam pressure (gauge) = 60 lb. per sq. in. 

Maximum temperature = 307°F. 

The comi)Osition of the above lye was as follows: Sp. Gr. 
1.0525 - 10.5°Tw.; total soda NasO = 32.49 grams (= 53.78 
grams sodium carbonate) per liter, of which about 82 % existed 
as hydrate {i.e. caustic soda), 9.3% as carbonate, and 8.3% as 
silicate, with traces only of sulphide. The silicate of soda is 
formed from the silica, which exists in very appreciable quantities 
in all cereal straws. As the whole of this silica is soluble, it 
affects the consumption of the recovered soda liquors and the loss 
of soda to a very large extent, since silicate of soda is quite useless 
for the cooking operation, and must be replaced by fresh soda 
ash in the recovery process. 

103. Cooking Process. — The digesters, as previously stated, 
are almost invarial)ly of the rotary type, either horizontal oi- 


vertical cylinders, Fig. 7, or spheres. The latter revolve on 
trunnions, and are provided with suitable manholes and covers 
for filling and emptying; also, with arrangements at the trunnions 
for heating the digester and its contents with steam. Some- 
times baffle plates are fixed inside, to promote the mixing of the 
charge; since the straw softens, and is apt to mat together into a 
mass, which slips as the digester rotates. Several times during 
the boiling, the revolving is stopped for a few minutes, and the 
air inside the digester is allowed to escape through a small relief 
valve. The most suitable digesters are the spherical type. Fig. 8, 
or the upright cylinder with coned ends (see Fig. 4, Section 6, 
Vol. Ill), driven by worm gearing, and having a capacity of from 
3 to 4 tons of straw. The charge of pulp and black hquor may 
be dumped or blown under pressure from these digesters into 
the wash tanks with greater care than from those of the horizontal 
cjdindrical type. The digester space required varies from 120 
to 150 cubic feet per ton of bleached-straw cellulose made per 
week. That is to say, 50 tons of fiber per week would require, 
on an average, about 6750 cubic feet of digester capacity. 

104. "Washing and Bleaching. — The contents of the digester 
are emptied or blown into the washing tanks, where the fiber is 
washed by displacement. These tanks can be arranged accord- 
ing to Shank's system, as applied to the lixiviation of ball soda in 
the Le Blanc alkali process, in which the wash Hquor (or water) 
flows from one to the other by gravitation (see Fig. 19, Section 5, 
Vol. III). Or, instead of this, the washings may be pumped from 
one to the other, the weak washing Hquor being distributed over 
the surface of the fiber in the receiving tank by a rotating spray 
pipe, as in the washing system arranged for soda pulp. In all 
cases, since the fiber is fine and settles down on the filtering 
medium in a somewhat compact mass, the displacement of the 
stronger lye by the weaker wash liquors (or water) goes on 
slowly, and reasonable time must be allowed for washing. For 
the same reason, an unusual amount of draining or filtering 
surface should be provided, about 35 square feet per ton of pulp 
per day. The washing of the fiber should be conducted with the 
greatest care, to avoid undue dilution of the black liquors going 
to the recovery house; for this reason, it should not be hurried. 

The washed fiber is then forked onto a travefling belt that is 
placed over these tanks, and which conveys it to a pulp opener or 
rafineur, to completely disintegrate it; or it is washed out with a 


hose, through a valve or door into a pulp chest that is fitted with 
an agitator, and from there is pumped to the opener. The object 
of the opener is simply to break up the bundles of fibers. After 
this, it passes to the bleaching engines — Hollander or Bellmer type 
(Vol. Ill, Section 9, Bleaching of Pulp), where it is given a final 
washing by a drum washer, Fig. 11, covered with fine-wire gauze 
(60 meshes to the linear inch), with pure, clean water prior to the 
addition of the calcium hypochlorite or bleaching powder. As 
in the case of esparto, the temperature is raised to 100°F. and the 
pulp is allowed to circulate until it reaches the desired color. 
Finally, the fiber is run off on a presse-pate machine, Fig. 19, 
into a thick web, or is passed over a Fourdrinier drjdng machine. 

These different operations must be carried out with care and 
intelligence, to avoid contamination with dirt; otherwise, the 
straw cellulose will not be suitable for the production of the 
highest-class writing papers, etc. 

105. Yields. — The amount of cellulose shown by chemical 
analysis of these straws, is never obtained in actual manufacturing 
practice, because a part of the fiber is lost during its manipulation 
in the factory, and a portion is dissolved b}^ the caustic liquor. 
The percentage found by analysis even differs for the same kind 
of straw from different districts. The whole question of yield 
is therefore a complicated one. Barley straw yields much less 
than oat, wheat, or rye. But when these thi'ee are used in about 
equal proportions, 100 lb. of dry straw (8% to 10% moisture) will 
produce from 40 to 41 lb. of bleached air-dr}^ pulp containing 
10% moisture. The proportion of caustic soda used per unit 
weight of straw in the cooking has a great influence on the yield 
and the bleaching properties of the fiber, as exemplified by the 
following table, compiled from actual practice by Roth: 

Situation of works 

1000 Kilos of straw 






of straw 


in fiber 

100 Parts of air-dry 
pulp required 




Kilos Kilos 

South Germany .... 225 

Austria 225 

Saxony I 240 

Bohemia 200 












A study of this table reveals the fact that the yield of fiber is 
varied indirectly with the amount of caustic alkali used. That is 
to say, the greater the amount of caustic alkali used, the less the 
yield of fiber. Also, that the bleaching powder required increases 
with the yield. These facts, it may be stated, are common to all 
fibers prepared by the soda method, and they have been con- 
firmed by many investigators, after careful experiment. 


(1) (a) Where does manila fiber come from? (b) how is it treated? 

(2) Why is jute limited to the manufacture of coarse papers? 

(3) Describe an esparto boiler. 

(4) What are the several kinds of pulp straw, and the use of each? 

(5) How is straw cooked for a yield of 75 %? 

106. Bamboo. — The enormous quantity of bamboo in the 
world, and its very rapid growth, makes this peculiar grass a 
promising source of paper-making material. The need for its 
exploitation is in sight; years of research by Raitt and others have 
shown the feasibihty of preparing bamboo pulp by the soda or the 
sulphate process. Indian bamboo contains 50% to 54% 
cellulose, and Philippine bamboo contains slightly more. Raitt 
found the soda process to yield 41% to 43% of bleached pulp 
suitable for high-grade papers. The sulphate process gives 
about 1% higher yield, with considerably less bleach — 15.5% 
to 18%. The sulphite process is unsuited, because of the amount 
of silica in the plant and the difficulty in maintaining a strong 
bisulphite Kquor in the tropics. See Indian Forest Records, 
Vol. 3, Part 3. 

Raitt recommends that (1) only shoots be cut that have 
attained the full season's growth; (2) that the culms be seasoned 
at least 3 months before use; (3) that it be crushed; (4) that the 
starchy matters be extracted; and (5) that the sulphate process 
be used. 

Satisfactory digestion of the five species investigated was 
found to be possible with 20%, to 22% caustic (hydrate and sul- 
phide), temperature 162° to 177°C., pressure 80 to 120 lb. per 
sq. in., and 5 to 6 hour's cooking time. 

Note. — Bamboo. Bamboo fibers closely resemble those from the straws 
in many of their characteristics. According to Raitt, the average length of 
the ultimate fibers is from 2.20 to 2.60 mm. according to the variety, and 
diameters are from 0.018 to 0.027 mm. While not so long as spruce fibers, 
they are much longer than those from any of the deciduous trees. 



(1) When and where were rags first used for making paper? 

(2) What kinds of rags are used for (a) writing paper? (6) 
wrapping paper? (c) roofing paper? 

(3) In purchasing rags, what materials would you limit or 

(4) Describe the rag thrasher, and tell what it does. 

(5) Why and how are rags sorted? 

(6) Describe the apparatus and the process of cutting rags. 

(7) What is accomplished in the cooking of rags? 

(8) Describe one type of rag boiler. 

(9) Explain the fiUing of the boiler and the cooking and 

(10) Name the variable factors in cooking, and state how a 
change in each one affects the others. 

(11) (a) Explain what happens to the rags while washing; (6) 
how long does this take, and how much water is used? 

(12) Why are rags bleached? 

(13) How is the bleach liquor prepared for bleaching rags? 

(14) Express your opinion of a foreman who used 12% of 
bleach for Thirds and Blues and added a chemical to neutrahze 
the excess. 

(15) (a) What are the items of loss in preparing rags? (6) how 
do these vary with different classes of rags? 

(16) What kinds of paper are made from manila hemp? 

(17) How does jute differ from other fibers considered in this 

(18) What is the prospect of using cotton-seed hull fiber or 
linters in paper making? 

(19) What is the source of esparto, and for what papers is it 

(20) (a) How is straw cellulose prepared? (6) what is the 

average ^deld? 

§1 ' «l 



By Ed. T. A. Coughlin, B. S., Ch. E. 



1. Reasons for Extensive Use of Waste Papers. — The use of 

printed waste paper, or old paper stock, as it is commonly called 
in the mill, has developed to such an extent on this continent 
that it rivals, even surpasses in some cases, the use of soda and 
sulphite pulps in certain grades of paper. There are many- 
reasons why old paper stock has reached this point of importance, 
some of which are: the immense available supply of material; 
the low cost of material ; low cost of converting into paper pulp ; 
desirability of the converted product. 

2. At the present time, old paper stock is employed in the 
manufacture of container board, box board, wall board, leather 
board, papier-mache, roofing paper, manilas, carpet paper, 
wrapping paper, bag paper and printing papers. In the finer 
grades of paper, such as book and printing paper, bod}^ stock of 
coated paper, lithograph and book papers, the cheaper grades 
of writing, mimeograph, offset, drawing, bible, blotting, map, 
parchment, music, catalog, tissue, water leaf and cover papers, 
the percentage of old paper stock used in them ranges from 10% 
to 80% of the furnish. 

3. It would be difficult to ascertain the limits of the field for 
consumption of old paper stock. This material, when properly 
de-fibered and freed from colors, dirt and ink, can be safely 
used in all but the finest grades of writing and record papers, 
and in papers that call for a specially long fiber, where the 
§2 1 


composition of the sheet to be made has been specified previously. 
Consequently, it is not strange that what formerly was a waste 
and a useless commodity now finds a ready application to almost 
every grade of paper made. 

By far the largest tonnage of this waste-paper material is 
re-made into boards, liners and newsprint; in fact, it has been 
estimated that about 10,000 tons of old paper stock is daily 
re-made into the classes of paper here mentioned, and about 2500 
tons is employed daily in the manufacture of book, writing and 
the other grades of the better class previously referred to. This 
Section will deal more particularly with this latter application 
of the great American waste. 

As a subject for discussion, "The Reclamation of Printed 
Waste Paper" has been almost as popular a theme as "A New 
Substitute for Wood Pulp." For years, it has been the goal 
of many determined paper makers, of many enterprising business 
men, also of many adventurous fakers, to work over old maga- 
zines, books, letters and bill heads, and even old newspapers, 
in such a manner as to produce a grade of paper equal in every 
respect to the original. Many machines have been devised, 
and many processes have been worked out in secret, to re-pulp 
and de-ink discarded paper, but a large proportion has resulted 
in economic failures. Notwithstanding quite extensive skepti- 
cism concerning the practicability of the process, thousands of 
tons of paper are daily being re-made into high-class book and 
printing papers and similar grades, which compete with, and 
sometimes quite materially undersell, the pure-fiber papers. 

4. Value of Waste Paper. — A more general appreciation of the 
market value of rags, rope, and waste paper of all kinds, would 
increase largely the supply of old paper stock; it would also add 
considerably to the income of the general public. According to 
figures for 1919 by the U. S. Department of Census, rags to the 
value of §23,000,000 were used in that year for paper making, 
besides $7,000,000 of rope, jute bagging, waste, threads, etc., while 
several times this amount could be secured under proper collect- 
ing conditions. Waste paper to the value of $43,000,000 was 
used in 1919 in paper making, and it is estimated that three 
times this amount could be made available. Even though 1919 
was a period of high prices, it is therefore evident that the value 
of the waste paper annually destroyed is very great ; if reclaimed 
and used, it would serve a^double purpose — the production of 


good paper, and the conservation of the material, largely wood, 
that the waste paper replaces. The 1,000,000 tons of paper now 
wasted each year, and which could be saved, would make all the 
building, bagging, cover, blotting and miscellaneous papers, and 
all the paper board, that is now produced. 

Considering, then, the immensity of the field and the profits 
to be derived, it is only logical that many methods should have 
been devised and patented for reclaiming old paper stock. 


5. Classification of Methods. — It would be almost an impossi- 
bility to collect and record all the different methods that have 
been patented. Those processes that are in practical use in the 
mills will be considered in detail. The methods are here treated 
under three heads: mechanical action alone, without the use of 
chemicals; chemical action alone; combined mechanical and 
chemical action. For each class, many processes, and the equip- 
ment therefor, have been patented. Some of these show a lack 
of knowledge or experience regarding their practical, economical 
operation. It may be remarked that few branches of the paper 
industry have brought out more patents than this. 

6. Mechanical Processes. — Very few methods of any value are 
to be found in the class that includes the processes grouped under 
mechanical action alone; for, to produce a good white pulp for 
book paper, it is necessary that the inks be entirely removed. 
Printing inks consist mainly of some pigment, which is combined 
with an oil or varnish body, called the vehicle. To remove the 
ink, saponification b}- an alkali of some kind is necessary, in 
order to effect a combination of the alkali with the vehicle and 
free the pigment. However, under mechanical action alone 
may be classed all methods employed in roofing and board mills 
that use only old newspapers, wrapping papers, and box boards. 
For the grade of paper there produced, the color is of secondary 
importance, and the products are usually heavily colored with 
loading ochers and red oxides. 

7. Chemical Processes. — Treatment of papers by chemical 
action alone is understood to refer to those processes in which the 
papers remain stationary, the liquor used being allowed to 
circulate and permeate the mass thoroughly. In this way, the 


ink is broken up, being deprived of its vehicle, and it is easily- 
washed out subsequently in the washing engines. This method 
is the practical outcome of the earliest experiments in treating 
waste papers; it is called the open-tank cooking process, and it is 
stilljargely in vogue in mills of the Middle West. 

8. The first description of a process of this type is credited to 
J. T. Ryan, of Ohio, and was patented by him. After being 
dusted, the papers are cooked with a soda-ash solution of 5°Be. 
at 160°r. 

In the method patented by Horace M. Bell and Edmund R. 
Lape, of Swanton, Vt., the dusted papers are agitated in a solu- 
tion of 1 part soap and 600 parts water for each 10 parts of 
papers; the loosened ink is then washed away. 

9. Combined Mechanical and Chemical Processes. — By far 

the greatest number of actual and proposed methods depend 
on the combined chemical and mechanical treatment of the 
papers; the most important of these is the rotary-boiler process, 
the details of which will be thoroughly discussed later. The 
cooking-engine process, and several other patented processes 
will also be considered in detail. 

10. John M. Burby states, in U. S. patent No. 1,112,887, that 
alkalis are most suitable for use as solvents in processes for the 
recovery of pulp from printed waste papers; but, if they are 
used in solutions containing more than the equivalent of 2 parts 
of caustic soda to 1000 parts of water, or if weaker solutions are 
employed at a temperature of 150°F. or higher, they produce a 
discoloring effect on the mechanical wood pulp that may be 
contained in such waste papers. Mr. Burby found that a solu- 
tion of 1 part (or even less than 1 part) of caustic soda, measured 
by weight, in 1000 parts of water, if employed in proportionate 
quantities, is sufficient in most cases to counteract the adhesive- 
ness of the oily medium of printer's ink. Other alkalis may be 
used in place of caustic soda. 


11. Grades of Papers. — Until recently, no definite standards 
or distinct classes were deemed to be necessary in the classifica- 
tion of waste papers. Perhaps the first distinctions made were : 
(a) Waste papers for No. 1 stock, such as shavings and cuttings 


of papers not printed upon and which could be used directly in 
the beater without preliminary treatment; (6) waste papers for 
book stock, which comprises practically all kinds of printed 
matter except groundwood, or mechanical, pulp papers; (c) all 
other waste papers, which are made into cheap box board. 

12. Quite naturally, paper manufacturers using these wastes, 
especially book-paper men, noticed that certain grades of paper 
produced a cleaner and more uniform sheet, and they therefore 
discriminated in their selection of stock; this has resulted in the 
following grades of waste papers, with their prices per 100 lb., the 
latter fluctuating according to the season and to the demand: 

Quotations on Waste Paper Oct., 1915 Oct., 1922 

No. 1 hard white shavings $2 . 40 -2 . 50 14 . 20-4 . 40 

No. 2 hard white shavings 2 . 00 -2 . 10 3 . 75-4 . 15 

Ledger, solid books 1.75-1.85 3.00-3.25 

No. 1 soft white shavings 1 . 75 -1 . 80 3 . 75-3 . 90 

Ledger stock 1.40-1.50 2.70-2.80 

Magazine, flat 0.80-0.90 2.45-2.50 

Magazine, unstitched, flat . 95 -1 . 00 2 . 65-2 . 70 

Crumpled book stock 0.70-0.75 2.10-2.15 

White blank news 1.05-1.10 2.00-2.15 

New manila envelope cuttings .... 1 . 50 -1 . 60 2 . 50-2 . 60 

Newmanilas 1.30-1.40 2.00-2.10 

Manilas, extra 0.90-1.00 1.80-1.90 

Manilas, No. 1 0.65-0.75 1.50-1.60 

Manilas, No. 2 0.35-0.45 1.40-1.50 

Bogus wrappers 0.42^-0.45 1.10-1.20 

No. 1 mixed papers 0.30-0.35 1.05-1.15 

Ordinary mixed papers 0.25-0.30 0.80-0.90 

Over-issues 0.50-0.55 1.20-1.25 

Folded news 0.35-0.40 1.25-1.35 

Box maker's cuttings . 30 -0 . 35 1 . 05-1 . 15 

Telephone books 0.25-0.30 0.55-0.65 

Even with these distinct grades, the mills are continually being 
annoyed with shipments that do not approach the quality speci- 
fied in the orders. If there is to be any profit at all, it is practi- 
cally impossible for the original packers to grade so closely that 
the stock can be used without subsequent mill sorting, particu- 
larly in the case of magazine, book, and mixed ledger grades. 
In these items, an allowance of 3% for groundwood is made to 
the packers; all over this amount is deducted from the original 
price of the stock, and is paid for as "print. " In magazine stock, 
an allowance of 3% is made for any book stock that may be 


found on sorting; if a greater percentage is found, it is paid for as 
ordinary book stock. Similar allowances are made in mixed 
ledger stock, which is very hard to grade. 


13. A Satisfactory Standard. — For a long time, there was 
considerable difference of opinion as to how to grade a paper over 
which there was a controversy regarding its correct classification. 
No set standards were in general use among packers until the 
Theodore Hofeller Company, of Buffalo, N. Y., issued a set of 
standards, which were found to be satisfactory to all the trade. 
This classification is as follows : 

14. No. 1 Book and Magazine Stock. — No. 1 books and 
magazines must be free from groundwood paper, parchment 
paper, magazine covers made of dark-colored paper, school paper, 
paper shavings, photogravure paper, and free from books with 
burned edges. The following are some of the books and maga- 
zines that will not be accepted as No. 1 books and magazines: 
Ainslee's, All Story, Blue Book, The Cavalier, Pearson's, Popular, 
Red Book, Top Notch, Short Stories, catalogues from mail order 
houses, cheap novels, telephone books, etc. Thick books, ap- 
proximating the size of Dun's Agency books, should be ripped 
apart, making each part the thickness of an ordinary magazine. 

15. Ledger Stock.^ — Ledger stock consists of high-class 
writing paper, account books, ledgers, letters, checks, bonds, 
insurance policies, legal documents, etc. The paper may be 
white or tinted, it may be torn into two or three parts, but it 
must not be torn into small pieces. Covers must be removed 
from books and ledgers. The following will not be accepted as 
ledger stock: Postal cards, school papers, telegrams, envelopes, 
parchment paper, tissue paper, copying books, manila paper, 
colored paper, railroad bills of lading, freight bills, ledgers or 
books with burned edges. 

16. Mixed Paper Stock. — Mixed paper consists of clean, dry 
paper from stores, offices, schools, etc. It may include wrapping 
paper, cardboard boxes, paper book covers, pamphlets. No. 2 
book stock, telephone books, crumpled newspapers, envelopes 
and paper torn into small pieces that is not good enough for 
book stock or ledger stock. The paper must be free from excel- 
sior, sticks of wood, rubbish, iron, strings, rags, leather or cloth 


book covers, free, in fact, from all material that cannot be manu- 
factured into paper. Bricks, concrete, and even dead cats have 
been found in waste papers. 

17. Newsprint Stock. — Folded newspapers must be clean, 
dry, flat, folded newspapers, such as come from private homes, 
newspaper offices, news stands, libraries, etc. Pamphlets, 
mixed papers, and crumpled newspapers, will not be accepted 
as folded news. 

18. Subdivisions of Standard Grades. — In book-paper mills, 
there is a considerable variety in the grades of paper made; as a 
consequence, a difference in the quality of old papers used in the 
furnish is called for. Most mills have only two grades, which 
they call No. 1 and No. 2. The No. 1 grade is made up chiefly 
from ledger stock, for solid ledger books form a very fine sheet. 
The No. 2 grade is made from magazines and books; and, although 
a good sheet can be made from this stock, it does not, of course, 
command as good a price as that made from No. 1. These two 
grades are sometimes further subdivided by calling the paper made 
from them Extra No. 1 or No. 2, and Special No. 1 or No. 2. This 
difference is created by the use of high-grade ledgers and No. 1 
school books, or by a variation in the pulps used. 

19. Another Standard Classification. — The following Standard Classifica- 
tion for Waste Paper has been adopted by the National Association of Waste 
Material Dealers to be effective from July 1, 1922, to July 1, 1923. Any 
person wishing to have this circular mailed to them, should forward their 
request to the Secretary, Times Building, New York. 

Baling. Unless otherwise specified, it is understood that all ^ades are 
to be in machine pressed bales. 

Tare. It is understood that unless otherwise specified, tare shall not 
exceed 3 %. 

Weights and Quantities. A carload, unless otherwise designated, shall 
consist of the weight governing the minimum carload weight, at the lowest 
carload rate of freight, in the territory in which the seller is located. 

Hard White Envelope Cuttings. Shall consist of all white, hard-sized 
(writing) papers, to be free of groundwood, ink and all foreign substances. 

Hard White Shavings. Shall consist of hard-sized, white writing paper, 
free from colors and tints, groundwood, and other substances. May contain 
machine-ruled and unruled paper but not print-ruled. 

Soft White Shavings. Shall consist of all white book-paper cuttings, 
free from groundwood, ink, colors, and not to contain over 10% of coated 

No. 1 Heavy Books and Magazines. Shall contain all books and 
magazines, which are to be free of crumpled and scrap papers, and shall not 
contain to exceed 3% of groundwood, leather, cloth and board covers. 


Mixed Books and Magazines. Shall consist of magazines and books, 
to be free from all other kinds of paper. They must not contain more than 
20% groundwood papers, leather, board and cloth covers and foreign 

Kraft Papers. Shall contain all kraft papers, free of waterproof papers. 
No. 1 Print Manilas. Shall be composed of a majority of manila 
colored papers, writing papers and office waste. It must be free of soft 
papers, news and box board cuttings. 

Container Manilas. Shall consist of manila and other strong papers, 
with soft papers such as news and box board papers eliminated. 

Newspapers, Shall contain dry, clean newspapers, free from all foreign 
substances not suitable for the manufacture of paper. 

Mixed Papers. Shall consist of all grades of dry waste paper, free from 
objectionable material or materials that cannot be manufactured into paper. 
Note. Variations of the above grades or grades not included in this 
classification are to be sold by description and sample or by sample. 

20. Price Fluctuation.^ — The fluctuation in the prices of the 
different grades of waste papers presents an interesting study; 
it is a direct indicator of conditions among the mills. For 
instance, the price of No. 1 magazine stock varied from $0.60 
to $0.90 in 1911, and from $0.75 to $1.10 in 1907; these figures 
include the highest and lowest prices in the years 1907 to 1912. 
These figures are quoted for the years given because the prices 
in the war years do not represent normal conditions. 

Variation in price is due to the law of supply and demand, and 
is also influenced by the seasons. In the spring and summer 
months, the collections increase, and the supply on hand with 
the packers increases to such an extent that storage costs neces- 
sitate a quick and ready market; as a result, the price naturally 
drops. In the fall and winter months, the mills having stocked 
up to full capacity, the demand for paper stock lessens; but, by 
reason of the increased cost of collecting, the prices usually 
increase. However, the price of the higher grades of ledger and 
shavings is not so flexible; the price of these is governed mainly 
by the available supply, and by the ruling price of the rags or 
bleached sulphite that enters into the manufacture of new paper. 


(1) Compared with the total supply available, what is the probable 
proportion of waste paper collected? 

(2) Under what classification can the processes of treating waste papers 
be placed? 

(3) What is the nature of printing ink, and what chemical action is usually 
jiecegsary to get rid of it? 




(4) Name a class of papers for the manufacture of which, chemical treat- 
ment of the waste paper used is not required, and state why. 

(5) On what basis are waste papers classified ? 



21. General Layout of Mill and Sorting Rooms. — The general 
plan, or layout, of old-paper sorting rooms is practically the 
same in all mills. The sorting rooms are usually situated in a 
comparatively isolated part of the mill, to avoid getting dirt 
in the finished paper; they are generally on the top floor of the 
mill, so the papers can be delivered by gravity to the cooking 





Approximate Scale 









4 Stories and basement 

Paper storage and sorting 


4 Stories and basement 

Paper storage, cutting and dusting 


2 Stories and basement 

Cooking building 


1 Story and basement 

Beater room 


1 Story and basement 

Machine room 


1 Story and basement 

Finishing room 


1 Story and basement 

Packing and shipping room 


1 Story and basement 

Power plant 


1 Story and basement 

Repair shop 

Fig. 1. 

or bleacher room. This arrangement causes the various steps to 
be progressive, in the course of manufacture, and makes the 
process continuous. A glance at Fig. 1, which is a plan of the 
mill, will make this clear. 




The sorting room must be well lighted and ventilated, since 
light is essential for close sorting; and the dust-laden air must 
be continuous!}^ removed, to preserve the health of the sorters. 
A diagram giving the general sequence of the various operations 
is shown in Fig. 2. 

Wasfe Paper 
in Bales 

Soda AsH or 
OVher Alkali 

and Sor+ing 




and DusTing 

Cookino| Liquor 
Siorage Tank 


Soaking Tank 
or Mixing Engine 

Cook mg and 
De- Fibering 

Pm Cai-chers 
and Screens 

Washing and 

B I eaching 
(If Required) 

Storage for 
De-Inked S+ock 

Fir,. 2. 


22.. Description of Bench System. — When the waste papers 
reach the mill, thej' are weighed in by the storehouse foreman, 
and the weight is written on a tag, which is securely fastened to 
the bale. If there is room for it, the stock is placed on a car, 
sent up on an elevator to the sorting room, and run alongside 




the benches, if the sorting room is well supplied with them; after 
the car has been unloaded, the stock is placed in the storehouse, 
in numbered bays. The storehouse foreman of a book-paper mill 
is well quahfied to judge the quality of the stock as it comes to 
him; and if he thinks it will run excessively to print or discards, 


a o 








n i 



















A - Foreman's Office 
B- Flevaf-or 
C- Scales 
^\ Red Room 


H-Incline Carrier 


L - 6 -Culinaler Dushr 

M' Incline Carrier 


O - 6-Cy Under Dusier 

P- Fan Dusier 

R -Horrizonfal Carrier 

S-Shrage forShckfobeSorfed 

n -Sorter's Benches 

A -Sorters 


o -Barrels of Sor fed Papers 

Fig. :',. 

making it too costly to sort, he holds up the unloading until he 
is further advised by the purchasing agent or the sorting-room 
foreman. This decreases the expense of sorting and increases 
the efficiency of the sorters. 

Fig. 3 represents a layout of the bench system of sorting old 
papers. The sorting benches are arranged along the sides of 


practically the entire room; this allows plenty of space in the 
center for trucking the baled and sorted waste papers. 

23. Testing Paper for Mechanical Pulp. — On receiving the bale 
of papers, the sorter first removes the tag, which she carefully 
retains; for it represents what the bale weighs, and her pay is 
based on this weight, a common rate being 15 cents per 100 
pounds. Her trained eye tells her at once how any particular 
bale will sort. She can frequently pick out groundwood 
(mechanical) pulp sheets, which are termed print, by the general 
appearance of the paper; if the paper is old, the yellowish color 
indicates at once that it is print. As a further test, she occasion- 
ally sprinkles a solution of aniline sulphate over the papers as 
they lie on the bench, the strength of the solution being | pound 
of ordinary aniline sulphate to 5 gallons of water. If any of the 
papers turn yellow after being sprinkled, they are at once dis- 
carded as print. This test is widely known, and it is extensively 
used, when the price of aniline sulphate is normal. When using a 
solution of the strength mentioned, the test is rather slow; 
consequently, for a more rapid test, a solution composed of equal 
parts of nitric acid and water is used to identify print. As an 
indicator, this latter solution acts almost instantaneously, 
giving a dark brown color to print. 

Phloroglucine is also a very satisfactory instantaneous indicator ; 
it is made by dissolving 1 gram of phloroglucinol in 50 c.c. 
of ethyl (grain) alcohol and 25 c.c. of concentrated hydrochloric 
acid; the solution should be kept in an amber-colored bottle. 
This solution imparts instantaneously a deep red coloration to 
groundwood. Another rapid test, which has quite an extensive 
use, is prepared by making a strong solution of caustic soda or 
soda ash; this also gives a yellow or brown coloration to print. 

24. The nitric acid test is not always certain, since it will 
give a brown color reaction to sulphite also. Hence, when anihne 
sulphate is not to be obtained, and if the nitric acid test is not 
positive, the sorter must refer to the foreman (or to his assistant, 
the floorman), whose long experience enables him to judge the 
paper in question by looking at it or through it, tearing it, or by 
trying the acid test himself. If there is any doubt at all in his 
mind, the paper is discarded; for, as previously mentioned, 
groundwood, or mechanical, pulp will cause trouble later in 
making a clean sheet of paper. 


25. Rate at Which Sorting Is Performed. — When a bale has 
been opened and the sorting begun, if it appear that close sorting 
will be required in order to remove all the print and discards, the 
sorter is required to work by the day. She is thus enabled to 
earn a fair wage, perhaps $2.65 per day. Otherwise, she would 
hardly be able to sort more than about 700 to 800 pounds per 
day, for which she would receive not to exceed $1.25. 

The quantity sorted per day, and the consequent cost of sorting, 
depends directly upon the quality and grade of the papers as 
received. The grades of waste papers chiefly used in book-paper 
mills are the following: magazine, book, over-issues, unstitched, 
lithograph, ledger writing, solid ledger and perhaps some 

Solid magazines are easily sorted. After removing the print 
magazines, the names of which are well known to the experienced 
sorter, the deep-color covers of the selected magazines are torn 
off and placed in a container that receives this kind of discards. 
Solid school book is also easily sorted, requiring only that the book 
backs be torn off and the book divided into two or three parts. 
Over-issues do not require sorting, for they run uniform, and they 
are fed direct to the duster by the conveyor; this is also the case 
with lithograph and unstitched papers, provided they are not 
received in sheets too large for the dusters to handle. Solid 
ledgers require only that the binding be torn off and the paper 
separated into suitable thicknesses, about | to f of an inch. No. 1 
hard and soft shavings seldom require sorting. On the above 
grades, each sorter can handle 2800 to 4000 pounds in 10 hours, 
depending on her dexterity and speed, and the cost of sorting 
is at a minimum, or 15 cents per 100 pounds. 

However, mills are seldom so fortunate as to receive such fine 
packings; such lots come only occasionally. The usual run is 
No. 2 book, magazine and mixed ledger. Although these lots 
are supposed to have been graded by the packers with due care, 
all sorts of papers may be found in them. The papers must all 
be handled separately; and the amount sorted will vary from 
1300 to 2500 pounds, averaging, usually, about 2000 pounds per 
sorter per day of 10 hours. 

The mixed-ledger grade causes the greatest difficulty; it is 
nearly always sorted by the day, and at a rate of about $2.G5 per 
day. In order that a sufficient supply may be on hand when 
necessity demands an immediate cooking of 30,000 to 40,000 lb.. 




5 or 6 sorters are constantly employed on this grade of stock. It 
is obvious that this amount could never be sorted at short notice 
at a normal cost, 

26. Loss in Sorting.— The sorters' discards constitute the first 
shrinkage or loss. All discards are classified as follows: Print, 
colors, bagging, carpets, wrappers, tobacco paper, wire and rope. 
For the period of a year, the amounts and percentages of these 
discards are shown in the following table : 


Total \°'^' 

dis- ^'t: 

, cards 
cards , 

(lb.) ^"^l: 

! cent) 

Discards consist of the following: 



; (lb.) 


Print ' Colors Backs ^^^f""^' 
i etc. 

Yearly total. ... 1 13,273,076 
Daily average. . [ 4.5fi90 
Monthly aver- i 

age 1 1,106,089 

1 1 
881,423J 6.64 
3034 6.64 

73,452 6.64 

I 1 

1874 lb. 

45,367 1b. 

1 ' 
1.45% 0.25% 0.83% 
665 lb. 114 lb. 381 lb. 

16,090 1b. 2772 1b. ; 9222 1b. 

From the above table, which was compiled from daily records, 
the per cent of total discards is 6.64%; this is the first direct 
shrinkage in handling old-paper stock, as it is supplied to the 
general trade. The table also shows that 4.11% of the discards, 
or 60% of this shrinkage, is due to print or groundwood. 
By the use of better graded or better selected stock, such as over- 
issue magazines of standard qualit}^, this part of the shrinkage 
can be reduced greath'. 

27. Containers for Sorted Papers. — After being carefully 
sorted, the waste papers are placed in barrels or other suitable 
containers, which will hold 100 to 150 pounds each. The con- 
tainers are placed alongside the benches of the sorters, and, when 
filled, are trucked away to the conveyor. The work of trucking, 
which is performed by men, appears to be quite laborious, ineffi- 
cient, and an antiquated system; but it possesses some good fea- 
tures, however. For instance, each container is numbered with the 
sorter's bench number; and when the papers are thrown upon the 
conveyor that carries them to the duster, the two men who attend 
to this work carefully examine the papers for any discards that 
may be present. If the amount thus picked out runs high, the 
container is returned to the sorter, with the papers that still 
remain in it, with instructions to sort it over again. 





28. Description of Carrier System. — By carrier system of sort- 
ing is meant the process of handling old-paper stock from the bale 
direct to the carrier or conveyor; this sj^stem is illustrated in Fig. 
4. Here the outline a b c d e f represents the same rooms as 
shown in Fig. 3, but with such changes in their arrangement as 
will adapt them to the carrier, or conveyor, S3'stem of sorting 
paper stock. Note the simplicity of the new arrangement, and 
gain in floor space, for paper storage. 

6 <^ " foremani Office 
•o - Elevator 
^/■Q" ^3 =Carners 
dj-a^-dj =Te6-l-Spratj Barm's 

M^ Motor 
oji = Inspectors 

° -Sorters 

D - Bales of 0/d fhper^fodf 
F^^ShredderorCuj-fer for 

S -SforacfefbrShck 
T 'Shrage fbrJbrfed Shck 


Ci dj 

0<=30 Oc=,0 I Qt 

otao 0c3O0c=i& 


Cg ^2 


O QcaO CfcaoOc^ 




Fig. 4. 

The bales of paper stock are arranged on both sides of the 
carrier Ci, C2, Cs, which may be made of any suitable length; 
one having a total length of about 55 feet, and a width of 2\ feet, 
has been found to be convenient and efficient. Three (3) bales 
of stock are placed on either side of the convej'or, and one bale 
at the head (or starting point) of the continuous belt. Two 
girls (sorters) are stationed at each bale, as shown diagram- 
matically in Fig. 4; thus 14 girls sort 7 bales directly onto the con- 
veyor. The discards ma}- be put into baskets or boxes, or they 
may be thrown into a chute under the carrier. At the mid point 
of the belts, sprayers c?i, d^., dz, are placed; these furnish a con- 


tinuous fine spray of a solution of aniline sulphate or other 
indicator (see Art. 23) directly upon the surface of the papers, 
as they pass by on the conveyor. An elevated barrel of solution, 
connected to a perforated pipe over the conveyor is a good 

The speed of the conveyor is 55 feet per minute; and when the 
belt has traveled 20 feet (which takes 22 seconds), the indicator 
solution will show the presence of groundwood, if any be present in 
the sorted papers. The use of this spraying test is very necessary, 
by reason of the prevalence of bleached groundwood in book 
papers. Since it is impossible to identify bleached groundwood 
by eye, it is necessary to test every sheet of paper on the carrier. 
All groundwood book paper is sent to the mill that uses paper 
of this kind. Two women inspectors are stationed at the delivery 
end of each carrier; their duty is to throw out any sheet that 
shows the typical color reaction of the indicator. 

It is obvious that the sorters who are grouped around the 
receiving end of the carrier cannot use up too much time in close 
sorting; they must keep the surface of the carrier completely 
covered with papers at all times. They must, therefore, be 
able to sort by sight, and they must have a good knowledge of 
the general run of paper stock. Anything that is groundwood, 
or which appears to be groundwood, or concerning the nature of 
which there is any doubt in their minds, is at once thrown out as 
a discard. The discards thus thrown out from the carriers are 
then closely sorted and tested at the usual sorting benches. 

29. Advantages of the Carrier System. — It has been stated 

that, with the carrier system, 20 girls can turn out 50,000 to 

55,000 pounds, gross weight, of paper stock per day of 8 or 9 hours. 

Taking the lower figure and assuming that each girl receives 

$2 65 X 20 
$2.65 per day, the cost per 100 pounds is — -^ — = $0,106 

= 10.6 cents. This may be compared with 46,000 pounds, gross 
weight, of paper stock, sorted by 30 girls by the bench system, 
at a cost of about 15 cents per 100 pounds. 

Further advantages of the carrier system are: the decreased 
wear and tear on the floors; increased storage space, by ehminat- 
ing the sorting benches; and the elimination of one-man trucking 
barrels and containers, which are required with the bench 




30. Machines Used. — The machinery in the usual dusting 
room consists of the conveyors, raihoad duster, fan duster, and 
the dust-collecting apparatus. For a capacity of 20 tons in 10 
hours, all the necessary power is supplied by a 35-h.p. motor. 
Drives for each of the above mentioned separate units are taken 
from a line shaft. 

31. The Railroad Duster. — The old method of handling papers 
consists in emptying the containers, full of papers, onto a con- 
veyor that runs at a moderate speed. Here the papers receive 
a searching scrutiny for discards, and are then carried on a second 
conveyor belt, which moves at about twice the speed of the first 
belt. The second belt carries the papers to the railroad duster, 
in which the papers are threshed, shredded, and thoroughly 
separated into individual sheets. The shredding is accompHshed 
by feeding the papers between two rolls having staggered pin 
teeth. The general details of a railroad duster are shown in 
Fig. 4, in the Section on Preparation of Rags and Other Fibers. 
A duster of this type, 4 feet in width and having 6 cylinders, has 
a capacity of 5000 pounds of waste paper per hour. 

32. The Fan Duster. — ^The end of the railroad duster empties 
into the fan, or cylinder, duster. One type of fan, or cylinder, 
duster is shown in Fig. 5, Section on Preparation of Rags and 
Other Fibers, in which is a central shaft, with wings, revolving 
rapidly, and an enclosing screen cjdinder, which revolves slowly. 

The general action of a fan duster is similar to that of other 
rotary dusters in use. The papers, which are introduced into the 
feed aperture of the slowly rotating screen, are rapidly struck, 
tumbled, and loosened up repeatedly by the fast-revolving 
beater; this action separates the dust and dirt from the papers, 
which then fall down through the screen to the bottom of the 
casing. This occurs while the papers are progressively beaten 
and tumbled along through the screen, to be discharged in a 
loose condition. 

33. Dusters for waste papers are often made similar to the 
one just described, but without the central shaft and its wings. 
In such machines, the papers are moved forward by making the 


screen in the shape of a frustum of a right cone. The papers are 
fed in at the small end and discharged at the other end, usually 
upon a belt conveyor or into a chute. 

34. To render the fan duster with a cylindrical screen capable 
of operating progressively and to tear the papers apart, beat, 
dust, and freely discharge them in a loose condition as fast as 
they are properl}' fed into the rotary screen, the screen is prefer- 
ably provided internally with a series of projecting bars. The 
bars taper, and those at the receiving end are much larger than 
those at the discharging end; this gives virtually a conical shape 
internally to the screen. The rotating beater also has pin teeth, 
and its general outline corresponds to that of the screen, though 
its diameter is smaller. In operation, the beater may make 30 
revolutions to 1 revolution of the screen; this ratio of 30:1 is not 
fixed, and it ma}^ be considerably greater or less. When the 
screen is about 10 ft. long and 5 ft. in diameter at the large end, 
and the beater is of corresponding size, a good speed for the 
screen is 8 to 10 r.p.m. and for the beater 250 to 300r.p.m. How- 
ever, good work may be done even though they revolve much 
faster or slower. The fan duster discharges the dusted papers 
onto a conveyor belt, and this, in turn, delivers them to the 
cooking tanks or to storage bins. 

35. Power Required. — The power necessary to drive the con- 
veyor belts is estimated to be 1 to 2 h.p.; for the railroad duster, 
10 h.p.; for the fan duster, 5 h.p.; and for the exhaust dust fan, 
about 10 h.p. These figures vary, of course, according to the 
load on the machines. 

36. The Dust. — The exhaust fan is connected to both dusters ; 
it carries off a continuous stream of air that is laden with dust 
and dirt of all kinds, which is conveyed to a dust collector, 
where the dirt is removed and the air is purified before being 
discharged outside. The amount of dust removed varies, of 
course, with the kind of stock being handled; in any event, it is 
considered to be an inconsequential item, say 100 to 1.50 lb. per 
day in a plant having a capacity of 40,000 lb. of paper. 

A sample of the dust was tested. After being ignited, the 
ash was white in color and was proved to consist of clay or 
insoluble silicate. As would naturally be expected, volatile 
organic matter constitutes the greatest part of the dust, which 
really consists of pure pulp fibers, in the main, and would serve 


as an excellent filler in certain papers. An analysis of the dust 
showed it to contain the following: 

I'br Cent 

Moisture at 105°C 5 . 90 

Pulp fibers 77.41 

Clay 13.13 

Alum 2 . 30 

Calcium sulphate 1 . 25 

Total 99 . 99 


37. Methods of Handling Papers for Shredding. — Some mills 
change the method of handhng the sorted papers from that 
usually followed. In one instance, in its endeavor to have the 
paper shredded better, the mill discards the use of the railroad 
duster, and employs a shredder, which reduces the paper to 
irregular pieces, about 4 to 8 inches square. The shredder has 
an exhaust fan connected with it, and delivers the papers to a 
continuous conveyor rake. The rake drags the papers up a 
short, inclined, coarse-meshed screen, in which much of the 
finer and heavier dirt is sifted out. The papers then go from the 
screen to the fan duster, where the}^ are treated as previously 


38. A Popular Shredder. — There are a number of good paper 
shredders on the market, and in use in various mills, which 
reduce the paper to a size that will quickly absorb cooking 
solutions. A short description of several of these machines will 
afford information concerning the principles made use of in their 

Fig. 5 shows two views of a popular make of shredder. The 
rolls Q open up the papers and pass them to the shredding rolls 
R, which are cleared by pin roll P. The capacity of the machine 
is 12 tons of book stock in 10 hours. From G to 10 h.p. will 
drive the machine at capacity, and no moclianical skill is required 
for its operation. 

39. An Efficient Type. — Another efficient type of paper 
shredder is shown in Fig. G; it is running satisfactorily at 




Fig. 5. 

several plants in the United States and Canada. The machine 
is composed of two rolls R, having projecting pins P. One roll 
runs at a speed of 500 r.p.m. and the other at a slower speed. 
The flywheel F takes up much of the shock and promotes smooth 

Fig. 6. 




running. This shredder takes 6 to 8 h.p. to operate it, and its 
capacity is 4000 pounds of book stock per hour. 

After coming through the shredder, the pieces will average 
about 2 inches square, and they are so well separated that the 
cooking solution can percolate through them to the best advan- 
tage. The machine is automatic in its action, and the only atten- 
tion it needs is a conveyor to carry the paper to the hopper H, 
at the top of the machine, and to another conveyor that removes 
the pieces to the bins or cookers. 

40. Stock Cutter. — A stock cutter is shown in Fig. 7; it is 
installed in many mills for cutting solid ledgers, books and heavy 
magazines. In operation, the waste paper is put into the wooden 

Fig. 7. 

apron box A ; it is then carried up by the rubber or canvas apron 
until it is caught by the large, or breaking-down, feed roll B; 
this roll carries the paper forward to the small feed roll Bi, which 
carries the paper forward until it is cut by four revolving knives 
C, two of which are shown in the illustration, which shear against 
the top bed knife E. The stock is then carried down, and is 
cut and re-cut by the four revolving knives against the four 
cradle knives D. The weight of the machine is 8300 pounds; it is 
so constructed that the shock and jar that result from the cutting 
of thick books is hardly noticeable, giving practically no vibra- 
tion. Its rated capacity is a minimum of 2§ tons per hour; but it 
has cut and handled 5 to 6 tons per hour, depending on the 
amount of power that can be furnished to it, and the length of 
cut desired for papers. Belt F removes the cut papers. 

41. A Well-known Shredder. — Another well-known shredder 
is shown in Fig. 8. Here A is a roll with projecting pins P, to 
open the stock, which is fed through the hopper H. The shred- 
ding is completed by blades or bars B on roll R, and the paper is 
delivered at T. This shredder takes from 5 to 15 h.p., depending 
on the size of the magazines or books fed to the shredding rolls. 




Note the different speeds of the two rolls, which is indicated by 
the difference in size of the pulleys F and G. This machine will 
shred 3 to 4 tons of magazines per horn". No repairs or mainte- 
nance charges have been necessary in mills that have had this 
type of machine for as long as five j^ears, and no labor is required 
for attendance. 

Fig. 8. 

42. A Powerful Shredder. — The writer visited a mill that had 
recently installed a new type of paper shredder. The work being 
performed with this machine was quite remarkable. Large 35- 
to 40-pound books, from which the covers had been removed, 
were fed to the shredder and cut into almost a million pieces, not 
over 1 inch square. The shredded papers are expelled from the 
machine by a strong suction of air; they are then sent through a 
rotary-screen duster to a fan duster, which blows the papers to 
the cooking tanks. 

This shredder, shown in Fig. 9, is a massive machine, weighing 
8500 lb. The cylinder A is 30 inches long, and carries 20 knives 
B (only 4 are shown in the cut) that cut against 4 stationary 
knives C, located under the lower half of the cylinder and set in 
the frame. The cylinder is 36 inches in diameter, and makes 650 
to 860 r.p.m. The length of the cutting edge of the revolving 
knives is 6 inches, and of the stationary knives about 38 inches. 
Consequently, when the paper stock is fed into the machine, it is 




cut a number of times, and it is reduced to a uniform product 
that is easily handled with an air blower through an 18-inch 
pipe. The feeding spout 
D is a combination of 
inclined and vertical sides ; 
£' is a conve3'or-belt roller. 
The power required to 
operate the machine de- 
pends on the quantity of 
paper to be shredded. It 
is recommended that 50 
h.p, be available when the 
production is 3 to 5 tons per 
hour, and that about 10 h.p. 
additional per ton of in- 
creased production per horn- 
be available, up to the max- 
imum capacity of the 
machine, which is 10 tons 

' Fig. 9. 

per hour. Hence, when 

operating at full capacitj^, 50 -f- (10 — 5)10 = 100 h.p. should be 

available, though not necessarily used. On the date of the visit, 

Fig. 10. 

the machine was producing 4 tons per hour; and it was computed 
from the ammeter readings that 35 h.p. was being used. Fig. 
10 is a layout of the conveyors used to feed this machine properlj'. 


A belt conveyor A brings stock direct from the waste-paper 
sorting room and delivers it to a rubber-belt conveyor B, which 
delivers it to a hopper H, from whence it is conveyed to the 
shredder D. The papers are shredded and separated thoroughly, 
so that all impurities will be removed on passing through the fan 
duster. A leather scraper E keeps the paper from following the 
conveyor, and a pipe F carries the dust to the blower, which 
removes it from enclosure G. 


43. Dusting Old Papers after Shredding.^ — Strange to say, the 
subject of dusting the old papers receives but scant attention; 
it is usually regarded as a mechanical process of dumping old 
papers through the apparatus, and no further thought is given 
to it. In reality, dusting and screening loose dirt from old waste 
papers by the fan duster in the dusting room, bears the same 
relation to the resultant finished paper that removing bark and 
rotten wood from the pulp wood bears to the production of fine, 
clean pulp. 

To produce paper free from dirt, it is necessary to remove the 
greatest amount of dust and dirt at the initial stage of the process. 
If the duster delivers thoroughly dusted papers, the subsequent 
steps will be greatly simplified. The cut and torn papers from 
the shredder should be given a thorough dusting, using a machine 
of the types described in Arts. 31 and 32, or even a single wire- 
screen cylinder. 

44. Prevention of Clogging. — The variation in the rate of 
feeding of old papers to the dusters is an important point to be 
considered. The apparatus is built for a certain capacity, say 
2500 to 4000 pounds per hour. Below the minimum and up to the 
rated capacity, the papers are delivered from the duster in good 
condition; that is, thoroughly disintegrated and dusted. But 
it sometimes happens that 4000 to 6000 pounds per hour are forced 
through the machine, causing it to become clogged, when it is 
liable to become dangerously overheated, by reason of the 
increased friction. The dust cannot then be properly handled 
by the exhaust fan, and it fills the air, making it almost impossible 
to live in such an atmosphere. As a consequence, the papers 


will come out still dusty and dirty, through this overburdening 
process. To correct this, the dusting capacity should be in- 
creased, and the screening area of the rotary screen should be 
enlarged, to produce thoroughly dusted papers. 



45. Reducing Cost of Sorting. — By using a few precautions, it 
is possible to reduce the first cost in the reclaiming of old papers. 
The first essential in reducing cost lies in the purchasing of old 
paper stock. Since the quality of the product of the mill is 
governed by its constituent materials, in other words, by what 
enters into the composition of the paper made, very careful and 
judicious selection of the waste-paper stocks is a prime requisite. 
Orders should be placed only with reliable packers, those that are 
known to live up to their guarantee of doing an honest business. 
It would be well to visit these packers at their sorting and packing 
rooms, noting the care they give to the handling of the papers 
as received, their equipment, and the amount of business that 
they conduct. Packers should receive specifications covering 
a strictly uniform, clean grade of papers, and they should follow^ 
out these orders to the letter. The Salvation Army has gone 
into the waste-paper business quite extensively, and their 
packings enjoy the reputation of being carefully graded and 
free from groundwood. They command a higher price for their 
wastes; but it is cheaper in the end to use their stock, or to buy of 
similar conscientious packers. 

In purchasing paper stock, the only consideration of the pur- 
chasing department should be to buy only that stock which can 
be recovered to meet the standard grade of the mill and which 
can be delivered to the paper-machine beaters at the least cost 
per ton, as received. The method of getting the information 
for purchasing on this basis, as practiced in a Wisconsin mill, is 
to have the laboratory or testing department make a time, 
quahty and shrinkage test on a unit lot of the paper offered on 
the market. These tests are then turned over to the accounting 
department, which estimates the cost per finished ton for the 




various grades. An example showing records of these tests is 
given below. 









CB i'oQ 











d un 

ut in 











to " 

fl« ft ftC 

03 3 





* 3— u 2 

o o 

o fl 







I 5 



M^ M 1 a ft 


o ft 






i ft 




^5^ £^ 








ogja i'SS 





M- .—V 


'a a 

e ft 

O (D 

O 00 

O « 

2 ft 

« ft 

;Sg« Ld^ 


J3 > 



V 0, 





*J 4) 
J3 > 


•53 3 




0) a 

'S a; 





^ft« ,^«= 









57, bags 


14, string 



382. paper 

307, G-W paper 








113 5087 

9, wire 



230, bags 
6, wire 


5, string 
859, G-W paper 








113 5217 



31, bags 


269, G-W paper 








113 6353 



122, bags 
27, wire 


298, G-W paper 










Summary of Above Tests 
(All figures based on weight of paper as shipped) 

Shrinkage in 

Shrinkage in 





rest of 


per ton for 

room ( %) 

process (%) 























46. Choice of Stock. — Only solid magazines, over-issues, un- 
stitched, school books and solid ledgers, together with litho- 
graph and shavings should be used, to reduce the cost of sorting. 
These grades require the separating of the heavy colors only, 
and a sorter can easily handle 3500 to 5000 pounds per day. The 
shavings can be added directly to the beater, provided they are 
imprinted, and there is sufficient beater capacity for completely 
brushing out the fibers; sometimes shavings are first put through a 
pulper. Instead of trucking the papers after sorting, they can 
1)0 sorted directly onto and delivered to the dusters by conveyors. 


In place of tearing magazines and books by hand, the work is 
accomplished better and more quickly by using machiner3^ 


47. Improving Quality. — The exclusive use of the grades 
mentioned in Art. 46 would increase the quality of the product, 
which would be more uniform in color and in cleanliness. The 
composition of the stock being constant, the subsequent cooking, 
washing, and bleaching operations would not be so variable. 
Paper free from groundwood specks and undissolved ink would 
be obtained, and an increase in price of from 50 to 75 cents per 
hundred pounds could reasonably be demanded. Further, 
because of their freedom from dirt particles, samples could be 
duplicated, a procedure not otherwise practicable. Finally, 
by employing the cutter for tearing and shredding these grades 
of papers, the labor now engaged in this work could be decreased 
40% to 50%, without decreasing the output of the sorting room. 

48. Utilization of Discards from Sorting. — The discards, 
which may average 40 to 50 tons per month, are properly sorted 
into classes; this is done in the sorting room, and necessitates no 
additional help. The print is usually separated into what is 
called white print and colored print. White print is sold as such 
to mills making cheap blanks and liners ; colored print and heavj' 
colors are usually sold for making into boards, and this is also 
the case with book backs. Occasionally, all these discards are 
worked over at the mill in which they originate, with about 10% 
of unbleached sulphite, which serves for making a fairly good 
quality of heavy card wrapping for shipping rolls, etc. However, 
considering the amount of dirt that must necessarily enter into 
this grade, and which pollutes the entire mill with refuse, it is 
not a paying procedure, since a much better grade of sulphite 
fiber wrappers may be made at almost the same cost. 

The colors might be sorted to each color — such as blues, reds, 
greens, browns, yellows — and cooked separately, washed and 
partly bleached, and then worked over into colors again. Since 
a majority of the fibers of these colored papers is made up of 
soda and sulphite, a sheet could thus be made that would sell 
for a good price. The only drawback might be that only a 
limited amount of stock of each color could be obtained, with 
the consequent problem of disposing of small lots. Since deduc- 


tions are made for excess discards when paying the original invoice 
of the paper stock, it is safe to say that it is more profitable to 
sell the discards outright, and there is no attendant loss in doing 


(1) Explain the differences in the layouts for bench sorting and fcr 
carrier, or conveyor, sorting. 

(2) What chemicals are used to detect the presence of mechanical pulp in 
waste papers? 

(3) About how much dust is obtained from the dusting of waste papers? 

(4) Why is it unwise to overload the dusters that handle the cut and 
shredded stock? 

(5) How can the purchasing department help the superintendent to get 
better results from the treatment of waste papers? 




49. Methods of Cooking.^ — The methods for cooking and 
de-inking old waste papers that are now in use are few in number, 
insofar as the principles utilized are concerned. However, 
each mill usually employs certain variations, which it considers 
necessary for the successful treatment of waste-paper stock. 
The three oldest methods in use are: (a) Cooking in open- or 
closed-top stationary tanks; (6) cooking in cylindrical or globe 
rotary boilers; (c) cooking in horizontal-circulating cooking 
engines. These processes will now be discussed. 

50. Cooking in Open Tanks. — This is by far the most usual 
method of cooking old waste papers; it is used extensively in a 
number of the older mills. It is designated the open-tank 
process because the cooking tank is not covered while the papers 
are being cooked. Most mills that use this process have their 
own ideas regarding the details, such as the strength of cooking 
liquor, time of cooking, kind of alkali to use, and temperature of 
the cooking liquor, and these differ very materially from the 
details of the original Ryan process (see Art. 8). These differ- 


ences are the result of many years of experience; and the mills 
have, by degrees, reached the point where they now have sound 
data for properly cooking old paper stock. 

51. The Cooking Tank.— The cooking tank, or bleach tub, as 
it is usually termed, is a stationary cyhndrical tank B, Fig. 11, 
built of Y^-inch boiler plate; 
it is 10 feet deep, 10 feet in 
diameter at the bottom, and 
10 feet 1 inch in diameter at 
the top. The plates are riv- 
eted so that all projections 
will be on the outside, in 
order to make the inside as 
smooth as possible. The tank 
is provided with a solid 
bottom C and a false bottom 
D. The false bottom is made 
of iVinch boiler plate, and in 
8 sections, 4 of which, Di, D^, 
Dj, Di, are shown in the 
illustration. To enable the 
cooking liquor to filter 
through to the real bottom, 
these sections are perforated 
with ^-inch holes, spaced 3 
inches apart from one an- 
other. This false bottom 
rests on a cast-iron spider, 
which has 8 arms Fi, Fo, etc. 
The spider rests on an octa- 
gonal framework of wooden 
blocks Gi, Go, etc., 6 inches 
square in cross section. The 
space between the two bot- 
toms serves to contain a large 
volume of liquor, which is 
forced up the 8-inch central 
pipe 77 by a steam injector K, when the cooking is in process. The 
arms of the spider are riveted, or otherwise fastened, by a flange 
L to the central pipe H. The top of the central pipe, which is 
about 9 feet long, is equipped with a baffle plate P, 10 inches in 



diameter, the under side of which is slightly concaved. The baffle 
plate is so designed that the liquor striking it is sprayed out- 
wards and downwards, thus covering the entire exposed surface 
of the stock in the tank with a shower of liquor. Near the top 
of the pipe is a U-shaped hook or bale R, of l|-inch round steel,, 
fastened by bolt S, for attaching hook T of the hoisting mechan- 
ism; hook R is allowed to swing downwards when not in use. 
V is a Ij-inch steam inlet, Vi is a l|-inch pipe, V2 is a 1^-inch 
plug valve for drain, and X is a 4-inch washout valve. 

The lifting mechanism is supported conveniently by erecting 
a pier or column on either side of the tank. A spur shaft carries 
two sets of pulleys, one for raising the spider slowly and the other 
for lowering it rapidly. The pulleys are belted to a main shaft 
that is situated at a convenient distance from the spur shaft. 
One open and one crossed belt are used. The spur shaft carries a 
bevel pinion that meshes with a large bevel gear, which turns 
like a nut on the long screw A, and lifts or lowers the spider. 
Over each tank is placed a hood, which has a vent for carrying 
off the steam and fumes. 

52. Furnishing the Papers. — After being thoroughly dusted, 
the papers are discharged onto a conveyor belt, which carries 
them to another belt on the floor above the cooking room; this 
latter belt brings the papers to chutes, which may be arranged to 
deliver the papers directly into the tanks; or the papers may be 
charged in armfuls at a time, by two men. This latter method 
may at first appear to involve extra labor and time; nevertheless, 
it is the better method, because of the more uniform distribution 
of stock. 

53. Furnishing and Heating the Liquor. — Before beginning to 
furnish (charge) the papers, the liquor is made up to strength, 
and the correct volume of liquor is added to the cooking tanks. 
It is then heated, by injecting steam under the false bottom, to 
about 200°-210°F. At this temperature, the liquor is forced up 
the central pipe and against the baffle plate, and is sprayed out- 
wards and downwards, in a full circle, over the entire upper 
surface of the stock. The spraying process is intermittent; it 
occurs only when the pressure of the steam under the column 
of liquor in the central pipe overcomes the weight of the volume 
of this liquor in the pipe, and projects it upwards against the 
baffle plate; and it continues until the excess pressure falls and 


becomes zero. The liquor then filters through the papers or 
runs down the sides of the pipe or the tank, returns to the 
bottom, and forms a new and cooler (also heavier) volume of 
Uquor for the steam pressure to work against. 

54. Dry Cooks. — The spraying action should be so regulated 
as to occur about 4 to 6 times a minute during the period that the 
papers are being cooked. Evidently, this spraying must occur 
more frequently while the papers are being furnished to the 
tanks, and it is then increased to about 10 to 15 times per minute. 
For this reason, some mills decidedly oppose continuous furnish- 
ing of papers direct from the chutes. They claim that papers 
falling continuously are not evenly distributed around the tank, 
that they are liable to become bunched 'or packed, forming 
pockets of dry papers that do not come into contact with the 
spraying liquor. This results in what is termed a dry cook or 
bad bleach; the ink is not acted upon, the sizing of the papers and 
the oily vehicles of the ink are not thoroughly saponified, and 
on the later washing of the papers, it is impossible to wash off 
all the ink and secure a clean, white pulp. 

In addition to the presence of the ink particles, another bad 
feature of a dry cook is that the paper itself, by not coming in 
contact with the liquor, will not be entirely reduced to a pulpy 
mass in washing, and it will not be thoroughly brushed out during 
the short treatment it receives in the beaters. Still, a consider- 
able percentage is fine enough to pass lengthwise through the 
machine screens; and, on being made into paper and calendered, 
these dry particles cause a mottled or blocky appearance in the 
finished paper. These troubles are attributed to the method of 
scattering the papers across the top of the tank. The remedy is to 
furnish the papers, particularly hard-sized ledger and lithograph, 
in scattering armfuls; the papers are thus ovenlj^ distributed, and 
they all become saturated with the spraying liquor before the 
next armful is thrown in the same place. With soft-sized maga- 
zine and book stock, the papers may be delivered from the chutes 
directly into the tanks; they are then raked and distributed 
evenly over the path of the spraying liquor by two men, one on 
either side of the tank. 

55. Preparation of Cooking Liquor. — In preparing a new cook- 
ing liquor, or fresh bleach, 1200 pounds of soda ash are dissolved in 


water, heated, and agitated until thoroughly dissolved; sometimes 
the equivalent in caustic soda is used instead of soda ash. This 
operation is carried on in the alkali room, on the floor directly 
above the cooking, or bleacher, room. The liquor is run from 
the dissolving tank into the cooking tank, which has previously 
been cleaned out and made ready for the new alkali liquor. 
Fresh water is turned into the cooking tank until it reaches a 
depth of 4| feet; with a tank 10 feet in diameter, this is equivalent 
to a volume of 2644 gallons, or a strength of liquor containing 
1200 -^ 26.44 = 45.4 pounds of soda ash to 100 gallons of cooking 
hquor. With a hydrometer, this liquor should test 9.15°Tw. or 
6.34°Be., at 60°F.;at 180°F., which is the temperature at which 
the mill test is usually made, the reading should be 3.15°Tw. or 

This strength of liquor will thoroughly cook 6000 lb. of ordinary 
soft-sized book and magazine paper. After long years of practice, 
this amount of alkali has been observed to produce the best 
results, and it is taken as the standard for this grade of stock. 
For cooking hard-sized ledger and deep-colored, hard-sized 
lithograph papers, the strength of liquor customarily used is 
6.9°Be. or 10°Tw. at 180°F. ; this reduced to 60°F. gives a reading 
of 10.7°Be. or 16°Tw. This reading is equivalent to 7.57% of 
soda ash by weight, or 1750 pounds of soda ash is required to be 
used to give this test. 

While this amount of alkali is excessive, it is not considered 
economical to reduce it; because the cooked papers might then 
show defects of one kind or another, and these would at once be 
attributed to the way the paper was furnished and to the wrong 
strength of liquor used. 

56. Before allowing the papers to be cooked over night, the 
liquor is again tested. A sample is taken while the liquor is being 
sprayed over the papers, and hydrometer and thermometer 
readings are also taken. By referring to the scale of corrections 
for the temperature, it is an easy matter for the alkali man to 
ascertain whether or not the liquor is up to the required strength; 
if not, he at once adds more of the alkali solution. All the liquors 
are tested, and the results are recorded on the daily report sheets, 
together with the amount of alkali used for each cooking. 

57. Duration of Cook. — The operation of filling each tank 
usually takes I5 to 2 hours to furnish 6000 pounds of paper. This is 


allowed to cook from 5 to 10 hours, even 15 hours, at times. Light 
book and magazine can be thoroughly cooked in 7 hours, which is 
the minimum length of time in which it is possible to obtain good 
results. When there is a shortage of paper stock, a tank is hurriedly 
furnished and is cooked for 5 hours, but the results are far from 
satisfactory. Although most of the ink will have been acted upon, 
a small percentage will sometimes remain uncooked, and this will 
reduce the quality of the resultant sheet. 

For most of the hard-sized ledgers and colored lithograph 
papers, 10 to 12 hours is considered sufficient, though if time is 
available, that is, if there is a large quantity of cooked papers 
ahead of the washers, the cooking time is increased considerably, 
even to 15 hours. This length of time is possible, if the^papers 
are furnished in the first tank filled in the morning; the tank will 
be filled by 9 a.m., and the papers are ready to be taken off by 

58. Steam Used in Cooking. — The amount of steam used in 
the cooking of the papers is an important factor in estimating 
the cost of the process; but no definite data have been obtained 
as yet regarding the amount consumed. The pressure on the 
main steam line is reduced by a valve to 30 pounds, the steam 
flowing through a l|-inch pipe to each cooking tank. Here the 
pressure is again reduced by a valve, and the amount of steam 
used is regulated by the number of intermittent showers or 
sprayings of liquor that are desired per minute. 

That the amount of steam used is excessive, is admitted by all 
those who have inspected the system. At times, after all the 
liquor has been sprayed up, it fails to return quickly enough to 
form a seal below the false bottom, for the steam to work against; 
the result is that live steam continues to be injected upwards 
into the open air until this seal is again formed. In a few mills, 
in order to retain the heat of the steam, the tanks are encased with 
wood or with an asbestos covering. 

59. Reducing Steam Consumption. — To reduce the amount of 
steam used, it was suggested that the tank be covered with a 
wooden or iron cover while the cooking was in progress. An 
opening 1 foot square was made in the cover, about 1 foot from the 
edge, and to this was attached a wooden outlet, which conducted 
the steam and vapor outside the building. While this arrange- 
ment reduced very materially the amount of steam used, it 


caused other troubles, due to excess condensation, etc., and it was 

One fact noted while using the cover on the tank, was the great 
difference in the amount of heat remaining in the papers, when 
they were ready to be taken off. The papers in the tank were so 
hot that it was necessary to allow the cook to stand and cool off, 
until the other cooks had been removed from their tanks. Even 
then, the papers were removed only with the greatest difficulty 
and discomfort. 

Although the increase in the amount of heat retained by the 
papers adds to the difficulty of handling them after cooking, the 
heat hastens the saponification action; the ink is more completely 
broken up and dissolved, and it is more easily washed out in 
the washers; the tendency of the ink to collect into small lumps 
is overcome, because, after being subjected to the continued 
heat action, the particles of ink are very finely subdivided and 
will more readily form an emulsion with the cooking liquor. 
Also, since more than two-thirds of the hotter liquor is recovered, 
and much more drains away while the papers are in storage, the 
subsequent washing time for the papers is lessened considerably. 

60. Removing the Cooked Papers. — After the papers have 
been allowed to cook the required length of time, the cooked 
papers are raised by a hoisting device that lifts the false bottom 
from the tanks. The hoisting mechanism is located on the floor 
above the cooking room. A 25 h.p. motor will furnish sufficient 
power to raise five cooks at the same time. 

When the false bottom has been raised to within 6 inches of 
the top of the tank, it is stopped; the papers are allowed to cool, 
and the liquor drains back into the tank. Two men clad in the 
scantiest attire, consisting usually of overalls and wooden shoes, 
mount to the top of the papers and shovel them off with pitch- 
forks into large cars or containers, which are grouped around the 
sides of the tank. The work is laborious; it is also distaste- 
ful, because the steam that continuall}'' arises is filled with peculiar 
odors from the papers. It usually takes 2 hours to fork off 
6000 pounds of the cooked papers, and the working time is 
limited to 5 hours for each man; the cost of handling the cooked 
papers is quite small. 

61. Other Methods of Removing Papers. — A method of 
removing the cooked papers that has been tried and found to 


be very satisfactorj^, is to attach 4 vertical rods, spaced equally 
distant apart around the false bottom; when the cook is raised, 
these rods form a kind of basket, and may be suitably fastened to 
an arrangement that will allow the entire mass of papers, still 
remaining on the false bottom, to be swung clear of the tank, 
onto a track system, and moved either by a crane or pulle}^ over 
to a draining pit. The false bottom is so built in this case that 
it permits dumping by turning on hinges. After draining in the 
pit for some time, the papers may be fed into a hopper or kneader, 
located below the pit, which will so condition the papers that 
they can be pumped to the washers. 

To accomplish this work with fewer men, one enterprising 
mill has laid a small, narrow-gauge, track system, sunk in a 
concrete foundation. The tracks extend from the tanks to 
each washer in the beater room, and to side tracks in the bleacher 
room; the latter serve to store papers ahead of the washer. By 
means of this track system, with small cars made to fit the rails, 
one or two men can easily convey the cooked papers to the 
washers. Some mills have an electric truck, which has an arm 
that is run under the box of stock, lifts it, and carries it anywhere, 
with no manual labor at all. 

62. Recovery of Chemicals. — The recovery of the alkaline 
cooking liquor used in the open-tank process is, perhaps, the 
best point in favor of this method of cooking old paper stock. 
The fact that no additional care, expense, or trouble is incurred 
in effecting the recovery of the liquor is also an attractive feature. 
Moreover, the cooking of paper stock is not nearly so satis- 
factory when done with fresh liquor as it is when part recovered 
Hquor and part fresh liquor are used, because the soap or saponi- 
fied oil that is contained in the recovered liquor has a definite 
and essential function to perform in emulsifying the carbon black 
and removing it in washing. 

The rate of ascent during the raising of the false bottom carrying 
the cooled papers, is very slow; it generally takes 30 min. to lift 
the papers 10 feet. This is a lifting speed of only 4 in. per min. ; 
and it is so slow that nearly all the liquor not absorbed by the 
papers finds its way to the remaining liquor in the tank. By 
thus slowly draining and running ofif the liquor, a varying per- 
centage of the liquor is saved. The degree of variation depends 
upon the nature of the papers, the soft, porous papers acting 
Hke a spongy mass to retain more liquor than the hard-sized. 


stiff, rag-stock papers. Another cause for variation is the loss of 
liquor due to splashing over the side of the tank while spraying 
with too great pressure of steam; also, when raising the papers, the 
liquor continues to ooze out of sides, and drains down to the rim 
of the top of the tank. If there is no opening by which the 
liquor can return to the tank, it will run over the sides and be lost 
in the drain to the sewer. However, with all these losses, the 
average daily recovery is about 66f % of the liquor used. In some 
cases, the recovery has been as low as 24% and as high as 92%. 

63. Losses in Recovery. — Figures tabulated from exact data, 
to show the variation in the percentage recovery of liquor that 
occurs from day to day under ordinary conditions, with seven 
tanks in use, indicated a maximum variation of 33.4% to 88.9% 
of recovered liquor. The monthly averages ran from 66.00% 
to 78.03%. Two tanks were furnished with new liquor during 
this period. The average recovery of soda-ash liquor on all 
tanks was 71.34%, with 146 cooks. 

In this tabulation, the variation was quite evident. At first, 
it was thought that the highest recovery figure, 88.9%, did not 
represent the same value as the corresponding volume or per cent 
of new liquor. It was claimed that from 20% to 30% of the 
alkali content was consumed in the saponification of the ink, 
colors, and sizings, and that the condensation of the steam caused 
the increase in the volume of the liquor. It is true that there 
is some decrease in the strength of the alkali content of the liquor 
by saponification; there is likewise considerable condensation 
while the liquor is being raised to the boiling point, though after 
that, the steam acts only as a projecting force to spray the liquor. 
The volume of steam and vapor given off on spraying is about 
equal to the amount of steam injected into the tank. 

As previously stated, there is a loss of liquor over the tanks in 
spraying, and in the liquor that oozes from the sides of the 
papers, while being raised, which fails to return to the tanks. 
There is a further loss in the liquor that drains away while the 
cars are standing in storage. All this liquor, which now goes to 
the sewer, could be very easily saved and recovered, and at slight 
cost. A concrete flooring, with grooved drains, would conduct 
all this liquor to a common catch-all tank. A catch pan could 
be riveted to the top of the cooking tank, into which would drain 
all the liquor that ordinarily goes to waste when the papers are 


64. Increasing Recovery by Washing. — The percentage of 
alkah recovered could be further increased by washing the papers 
once or twice with warm water, while they still remained in the 
cooking tank. This would necessitate draining off the liquor 
from the tanks before adding the wash water, in a manner similar 
to that of washing chemical pulp. But this is not desirable, 
since the soapy liquor sticking to the papers acts to remove the 
carbon black, when put into the washing engine. The strong 
liquor should be stored separately, and the wash water should be 
stored by itself in another tank; in this way, with a little care 
and attention, the strength of the liquors in all the tanks would 
be the same. The strength of the recovered liquor could be 
determined, and its volume readily ascertained. Then, by using 
the wash water to dissolve the correct amount of soda ash, and 
adding to the strong liquor, the strength and volume of the 
mixture could be brought up to the standard strength for cooking. 


65. Reasons for Using the Rotary-Boiler Process. — The 

cooking of old-paper stock in rotary-cylindrical and rotary- 
globe boilers is a later development that is viewed with great 
favor by all the newer mills. The cleanliness of the cooking room, 
the absence of steam and condensation, and the ease with which 
the cooked papers are handled, are the great assets of this method. 
The claim is also made that it is a much more economical process. 

Although the saving in labor, both in filling the rotaries and in 
the subsequent washing operations, represents a very good return 
on the investment, the chief argument in favor of the rotary 
sj^stem is the uniformity of the cooked product. 

The general arrangement of a cylindrical rotary boiler installa- 
tion is shown in Fig. 12. Details of the boiler are given in the 
Section on Treatment of Rags, etc. 

66. Discussion of the Process. — The preliminary sorting and 
dusting is much the same as in the open-tank process. A few 
mills have, very wisely, added cutters or shredders to their 
equipment, which help to condition the papers for the best 
results in cooking. The tendency for the papers to roll up into 
thick wads, caused by the slow, revolving motion of the boiler, 
sometimes gives trouble. These thick wads of paper are not 


thoroughly saturated with steam and cooking liquor, and the 
result is the same dry cook mentioned in Art. 54. To avoid 
this, the papers are first cut into short strips or are shredded 
into irregularly shaped pieces, that they may come more readily 
into contact with the liquor, and not roll up into wads. 

However, improvement in the design of the rotary-cylindrical 
boiler in the last few years, has overcome the tendency of the 
stock to roll up, or ball up, into dry wads. Investigation has 
shown and practice has proved that, by increasing the number 
of the internally projecting pins and by staggering and placing 
them in proper positions, the rotary will not only cook thoroughly 
but it will also act as a de-fibering machine. In the 8 X 24-foot 
rotary, the present practice calls for a varying number of these 
rag or de-fibering pins, which are usually arranged in 5 to 9 
rings of 8 pins each, the 8 pins being spaced uniformly about 
the circumference. The pins are made of | X l|-inch iron, bent 
to the shape of a U, and 9 in. high; they are riveted to the shell. 
The specifications formerly in use designated only about 9 or 10 
of these pins. One mill that is equipped with this new type of 
rotary reports that it has abandoned entirely the use of cutters 
and shredders, and that it has even eliminated the railroad 
duster and the fan duster in its sorting and dusting rooms. 
Instead of using a 50- to 60-h.p. motor to drive the sorting- 
room equipment, as formerly, a small 5- to 10-h.p. motor now 
handles the load of the three or four sorting carriers, the papers 
are conveyed in their original condition directly to the rotaries, 
and a heavier cook can be handled. The charge has been 
increased from 7500-9000 pounds to 12,000-14,000 pounds. 

Without a doubt, the older rotaries could not have accom- 
phshed what those of the newer type have done. It is a question, 
however, whether good judgment was exercised in discarding 
the dusting equipment at the mill above referred to. Dirt must 
be taken out some time; and the proper place is where the papers 
are dry and are in their original condition. Bearing in mind 
that the purpose of this mill was to keep the paper stock as flat 
and as compact as possible, the use of a revolving, tapering, 
cylindrical-screen duster would remove the surface dust by a 
tumbling action, and it would add but little, if anj^thing, to the 
bulk of the paper stock entering the rotary boiler. 

67. Fig. 12 shows the relative positions of the rotary and the 
dumping pit. Here R represents a typical 8 X 24-foot rotary; T 



and T, the trunions, or bearings, one of which is hollow, for 
admitting steam; G, the motor driving gear; P, the dumping pit; 
F, the discharge connection. View (c) shows the agitator 
device A, used in modern pits for dumping of stock, and its drive. 

68. Furnishing the Rotary. — After being discharged from the 
dusters onto a conveyor belt, the papers are delivered in a con- 
tinuous stream to the manhole opening of the boiler. There is a 
difference of opinion in regard to the correct procedure for 
furnishing the papers and the liquor. In one mill, the practice 
is to furnish the papers first, packing them with long iron prod- 
ding rods; the liquor is then run in all over the papers. It is 
claimed that by this method the papers are more uniformly 
acted on by the liquor; also, opportunity is afforded for packing 
the papers, so they will not tend to float when the liquor is 
added, thereby decreasing the capacity of the boiler. 

A second method in vogue is to furnish the papers and liquor 
together. In this way, it is thought that the papers are more 
thoroughly soaked with the liquor, and the possibility of a dry 
cook is overcome; also, the total time for filling the rotary is 
diminished, which is a valuable factor in costs and production. 

A third method consists in running in the required volume of 
soda-ash solution first, and then furnishing the papers. The 
argument in favor of this method is that there will be absolutely 
no dry spots in the papers, and a much cleaner pulp will result, 
with a thorough cooking. 

69. Amount and Strength of Liquor. — ^A rotary boiler 8 feet in 
diameter and 24 feet long is considered to be of the most efficient 
size for cooking old papers. A boiler of this size has a capacity 
of 1200 cu. ft., and it will hold from 5 to 7 tons of dry paper 
stock, depending on the grade and condition of the papers. 
Since the strength of the liquor used for cooking has never been 
standardized, the widest variation in this item is found in the 
different mills. Upon inquiry, one mill stated that they used 
water only as a detergent; another mill reported that the}^ used 
lime and water; still another method in practice is dependent 
upon the action of a soap solution, together with a small, quantity 
of free alkali. 

70. An accurate statement from data received showed that 
another mill was using 3456 gallons of liquor per 10,000 pounds of 
paper; in this liquor was dissolved 1200 pounds of 58% soda ash 


and 225 pounds of 76 % caustic soda. These alkalis are dissolved 
in two tanks, each 7 feet in diameter and 7 feet deep, filled with 
water to a depth of 6 feet, the combined contents being used for 
one cook. These tanks are equipped with a cover (an opening 
2| feet square being allowed for the introduction of the alkalis), 
agitator arms, and a steam injection pipe. 

A further report from one of the largest mills treating waste 
paper stated that their consumption of soda ash amounted to 
8% to 9% of the gross weight of the papers, as received in the 
sorting room. If an allowance of 10% be made for discards 
on sorting, this consumption would be at the rate of 9 pounds to 
10 pounds of soda per 100 pounds of net sorted papers. 

The lack of uniformity in the amounts of soda ash used for 
cooking paper stock is readily perceived from the figures stated, 
and no attempt has been made to standardize this figure. 
During the last few years, however, when the price of soda ash 
advanced to 3| to 5 cents per pound, this chemical was viewed 
with more respect, and efforts were made to reduce its con- 
sumption. Mills that formerly used 8% to 10% are now using 
4% to 5 %. Should the reduction stop at this latter figure, or is it 
possible to go still lower? Very careful experiments are being 
conducted at one or two mills to determine this safety point. 
Cooks have been made using 3%, with no bad effects; but this 
low figure is not to be considered as a criterion for a standard, 
since conditions are not always the same at all mills. Too many 
variables enter into the problem, which must be solved by each 
individual mill to suit its own equipment and conditions. It 
is to be hoped that with the adoption of standard cost methods, 
further research will be brought about in different mills, and that 
the results obtained will be interchanged more freely. 

71. Amount of Water Used. — In standardizing rotary cooking, 
the volume of water used should be a known, constant figure. 
From inquiries made at numerous mills, only one had in practice 
a method of measuring the water. Many mills stated that they 
filled the rotary up to a certain viark, or else permitted a water 
line to be open for a certain length of time. Here, at least, is a 
step that can be taken in the direction of a standard for uniform 
operation — the installation of a water-measuring tank. 

72. Rotary cooking accomplishes two things at the same 
time; viz., de-fibering and de-inking. The de-inking has been 


considered a chemical change, but it may also be classified as a 
physical change. The slow revolving motion of the rotary 
creates a tremendous amount of friction of surfaces, of attrition 
of particles of paper, and the combined action gradually separates 
the paper stock into its component parts — fiber, filler, size, 
and ink particles. AVith lapse of time, this action produces a 
colloidal solution, or suspension, of ink particles and fiber 

73. Increasing the Effect of Friction. — The question naturally 
arises — how can the friction between the inked surfaces of the 
paper be increased ? Speeding up the number of revolutions per 
minute of the rotary may help, but onl}^ to the point where the 
stock gets the greatest tumbling action, and without cling- 
ing to the shell on account of the increased centrifugal force. 
Increasing the number of pins or angle bars may help; but it 
may have an adverse effect, if the rotary speed be not carefully 
worked out. The use of too much water will increase the slip- 
page of the particles of stock upon one another, allowing the stuff 
to slip around without doing much de-fibering. Likewise, by 
not using sufficient water, danger of uncooked papers may be 
encountered. It would therefore appear that this factor in 
rotary cooking is a very important one; and careful supervision 
as to results obtained in using varying amounts of water will 
prove this statement. Cooked stock that is in a finely ground 
state, with particles not larger than a bean, and which has 
soaked up all the liquor possible to saturate it, with no residual 
unabsorbed or free liquor present, can be said to have had the 
proper consistency of paper and water during the cooking period. 

74. Duration of Cook. — When the liquor and papers have 
been completely furnished, the manhole covers are bolted down 
and securely fastened. The steam is turned on and the rotary 
boiler is set in motion. A recent improvement in the construc- 
tion of the rotaries provides for the regulation of the amount and 
frequency of the steam injections. An automatic valve is 
attached to the steam inlet, which operates and blows steam 
only when the pipes are submerged in liquor. The advantages 
of this arrangement are easily observed by the decrease in the 
amount of steam used, the more thorough cooking action, and 
the elimination of the possibility of scorching the papers with 
live steam. 


75. Variation in the time of cooking and in the steam pressure 
used, is another feature of operations in different mills. The 
data received shows that the cooking time varies from 1 to 10 
hours, and that the steam pressure varies from 10 to 50 pounds, 
One mill recommends cooking 6 hours under 40 pounds pressure, 
while another mill cooks 10 hours under 50 pounds pressure. A 
mill that makes a very good grade of paper reports that a mini- 
mum of 7 hours is required for a good cook, and that 2 hours 
extra is allowed to reduce the pressure, blow off the liquor, and 
dump out the papers. The cooking in this case is conducted 
under 20 pounds pressure. 

The variations here noted are attributable to the different 
procedures in practice. In the practical application of rotary 
cooking, it is generally conceded that there are three distinct 
factors that enter into the correct cooking of the papers. These 
factors are: (1) Volume and strength of cooking liquor per 100 
pounds of paper to be cooked; (2) time allowed for cooking, ex- 
clusive of time necessary for blowing off pressure and dumping 
papers ; (3) steam pressure used in cooking. 

These three factors balance one another. If any one of the 
three be varied, the other two must be varied also, but in the 
reverse or opposite direction, to make the balance perfect again. 
The data received from the different mills establishes the truth 
of this observation . One combination shows : 1494 pounds of soda 
ash in 3500 gallons of water per 10,000 pounds of papers, cooked 7 
hours, at 20 pounds pressure; a second combination is: 14,000 
pounds of papers, cooked 10 hours, at 50 pounds pressure, in a 
weak solution of soda ash. 

76. Dumping, or Emptying, the Boilers. — The construction 
of the rotarj^ boiler is so arranged that when the boiler is revolved 
and stopped, with the manholes facing downwards, the cooked 
papers discharge from the openings, the manhole covers having 
been removed. There is sufficient incline on the inside of the 
boiler to cause the papers to be removed almost entirelj' by 
gravity. The few remaining papers, if any, are raked out with 
a long-handled iron hook. 

The papers are discharged below the rotaries into dumping or 
draining pits. Some of these pits, or tanks, are equipped with a 
perforated strainer, which allows the liquor to drain off into a 
separate catch pan, to be used over again, if desired, in making 
up the new liquor for the next cook. The dumping pit is 


equipped with two washout valves, one draining valve, and 
one large outlet, for the removal of stock to the washers. 

77. Recovery of Liquor. — The recovery of the soda-ash liquor 
used in rotary boilers is apparently lost sight of; but, inasmuch 
as the papers absorb most of the liquor, there is only a relatively 
small volume that freely drains off into the dumping pits. The 
papers treated in a rotary are reduced to a pulpy consistency, 
due to the continued rubbing and grinding action. The pulpy 
mass acts like a sponge, and will absorb and hold, by capillary 
attraction, a large volume of water; consequently, unless it is 
allowed to drain for a considerable period, the recovered liquor 
will be a small item. 

The data collected on the recovery of the liquor gave results 
that varied from 11% to 50%, the general average being about 
30%. One mill reported that they did not expect to recover 
any of the cooking hquor; it was worthless, in their opinion, 
and would merely discolor any fresh liquor that was made for new 
cooks. A second mill reported the average to be approximately 
15%; and a third mill observed that the average was, roughly, 
33%, or one-third of the liquor used. 

78. A very enterprising mill stated that they had been thinking 
about this loss of soda ash for a number of years, but had done 
nothing definite to prevent it. They employed a chemist, who 
advised them further concerning the value of this waste, and they 
immediately took steps to provide a suitable drainer and catch 
pan for the liquor. In the dumping pits, the cooked papers 
are now subjected to a wash of warm water after as much as is 
possible of the cooking liquor has drained away. When the first 
wash water has drained off, a second wash water is applied; in 
this manner, the recovery was increased to 60%. Such efforts 
will pay, no doubt, when 8% to 10% of soda ash is used, and when 
the price of soda ash is high; but it is a very debatable question 
when only 3% of soda ash is used, as is now frequently the case. 
The cost entailed in saving the waste may be greater than the 
cost of the chemicals saved. 

79. Spherical Boilers. — This type of cooker is operated in the 
same manner as the cylindrical type. An illustration of a 
spherical, or globe, boiler is given in Section 1 of this volume. 

80. Power Required. — The manufacturers recommend the use 
of 8 h.p. for an 8 ft. X 24 ft. boiler; but actual practice has shown 


that 4^ h.p. is sufficient. One installation of this size of rotary- 
calls for a 5 h.p. motor for each rotary, and the motor is seldom 
called on to approach its rating. The boiler revolves so slowly, 
about 1 revolution every 2 or 2j minutes, that the driving power 
required is small. 

81. Furnishing Cooked Papers to Washers. — After the cooking 
liquor has drained off as much as possible, the papers are ready 
to be furnished to the washers, and this is effected in one mill by a 
very ingenious arrangement. It was previously stated that it 
required the combined efforts of six men to move the loaded cars 
of cooked papers to the washers when the open-tank method of 
cooking was used. In the mill here referred to, in which rotaries 
are used, the dumping pit is equipped with a dumping valve that 
leads into a vertical cylinder, about 3 feet deep and 2 feet in diam- 
eter, placed directly under the dumping pit and equipped with 
agitator propellor arms that are driven from a separate motor. 
The pulpy, cooked papers flow toward this cylinder, and they are 
hastened along by a water-pressure hose line. In the cylinder, 
they are agitated, to prevent any clogging of the pipe line through 
which the papers are pumped direct to the washers. This 
procedure effects a great saving in time, in labor, and in cleanli- 
ness of the cooking and washing rooms. 

Fig. 12(c) shows a cross section of an agitator device A now in 
quite common use in the more modern mills; it is a very simple 
arrangement, and is entirely satisfactory in operation. A careful 
examination of the drawdng is a sufficient explanation of the 

82. Remarks Concerning the Rotary Process. — The rotary 
process for cooking old-paper stock, and the dependent methods 
of handling the cooked papers, is regarded as the most convenient, 
the most efficient, and the most practical method in use. This 
view is held, in particular, by those mills that have rotaries in 
use or which expect to install them. While initial cost is con- 
siderable, the absence of steam and condensation and of the 
accumulation of papers and alkali liquors, the lessening of depre- 
ciation throughout the entire process, and the decrease in the 
labor cost attending the cooking and washing processes, are 
considered to be factors that more than counterbalance the extra 
first cost of installation. The entire process is more healthful 
to the workmen, and the cleanliness throughout appeals to all 




who are familiar with other methods of treating waste papers. 
Some recent developments, however, have features which are 
strong arguments for the newer processes. 


(1) State the advantages of a rotary boiler and explain the method of 
furnishing it. 

(2) How much soda ash is commonly used per 100 lb. of paper cooked? 

(3) Why is the amount of solution used so important? 

(4) How does the rotary help to de-ink waste paper? 

(5) What is the next step after the cooking is complete? 


83. Description of Cooking Engine. — The cooking engine for 

waste papers is a machine of the type shown at A, Fig. 13; it is 
essentially a variation of the beater or washer described in 


Fig. 13. 

Sections 1 and 3 of this volume. An elliptical-shaped tub, about 
8 ft. X 20 ft. and 3 feet deep, is divided down the center b}- a mid- 
feather, and in one side of the channel is a beater roll or propeller. 
The tub is covered as tightly as possible with steel plate, the 
end covers being hinged and held dow'n by bolts or clamps. 

Waste papers are prepared^ as previously described; the}' are 
stored on the floor above or in bins, and are furnished by a chute B, 
Fig. 13. The cooking liquor, usually a dilute solution of soda ash, 

1 In Fig. 13, Cr is a bale of papers, H a belt conveyor, K a railroad duster, 
L a sorting conveyor, M a fan duster, N an inclined conveyor, P a pile of 
prepared stock. 


is run into the engine A until the alkali content is equivalent to 
10% of the weight of the papers that the engine can handle. This 
amount will fill the tub to a certain depth, say half full. The 
papers are then furnished and are circulated by the roll or paddle, 
and they are soaked with the liquor at the same time. Water is 
added as necessarj^, and more papers are fed in until the desired 
consistency, about 6%, is reached. A charge is about 1200 lb. 
of papers. While the charge is being furnished and washed, the 
contents are heated bj- steam, at full boiler pressure, for about 
1^ hours. The agitation created during circulation de-fibers the 
paper and assists the chemical action of the liquor in loosening 
the ink particles,, which are removed in the subsequent washing. 
The cooking time is about 2 hours, varjdng somewhat with the 
grade of the waste papers ; old ledger and the like require a longer 
time to disintegrate. The power required is used almost entirely 
for circulation, and will average 25 to 30 h.p. 

84. When the papers are thoroughly cooked and re-pulped, a 
valve is opened, and the pulped papers are allowed to flow into 
chests C, Fig. 13. No attempt is made to recover any of 
the cooking liquor, as it is considered not to have any value. The 
papers are furnished to the washers D by pumping from the 
chests C into which the papers were dumped after being cooked. 
After washing, the stock goes to chest E, from whence it is 
pumped to the beaters F. 

85. Advantages of the Process. — The cooking engine process 
is claimed to have the following advantages: (1) Dusted papers 
are furnished from storage direct to engines; this provides for a 
storage always on hand, and it calls for a minimum of labor for 
furnishing. (2) Engines are covered tightly ; this saves in steam 
and heat. (3) Papers are re-pulped better than in the old type 
of rotaries; this lessens the amount of work required later for 
beating and brushing out in washers and beaters. (4) Papers 
are thoroughly soaked in the cooking liquor; there is here no 
possibilit}^ of a dry cook. (5) Papers are handled by gravity, 
both before and after being cooked; this eliminates the hand 
labor — a costly item in the open-tank process. (6) Small labor 
cost throughout. 

What may be called disadvantages or costly features are: (1) 
No recovery of the cooking liquor; this results in a large con- 
sumption of soda ash. (2) A large amount of steam is used; full 



boiler pressure is maintained for 1^ hours. (3) Large expen- 
diture of power is required to circulate the papers. (4) The oil 
consumption and belting wear and tear is large; extra with belt- 
driven pulleys. (5) General wear and tear and depreciation are 
greater. (6) The pulp product is considered to be weaker ; caused 
by the violent action of the steam, alkali, and the brushing action 
on the pulp. (7) Poor color of recovered pulp, compared with 
open-tank pulp, and not as good as rotary pulp. 


86. Treating Old -paper Stock Mechanically. — A new (patented) 
method has recently been perfected; it is in use in a few places, 
but has not as yet been completely adopted in the older mills. 
This method is largely mechanical in its action, and the details 
are illustrated in Figs. 14 and 15. The advent of this machine gave 
a wonderful impetus to the idea of treating paper stock mechanic- 
ally. There is now quite a varied line of processes that might be 
thought to have originated from the idea of propeller de-fibering; 
these will be considered later. 

87. Description of the Process.— This process was first brought 
to the attention of the general public in 1914-1915. Fig. 14 

illustrates the design of the 
machine, which consists of an 
inner cylindrical tank A that 
leads, at its bottom, into a 
draft tube B, through which 
extends lengthwise a shaft F, 
to which are fixed two pro- 
pellers C and Ci, spaced apart 
from each other, and of differ- 
ent pitch. The propellers, 
which are rotated at about 
2000 r.p.m., draw the material 
downwards from tank A , drive it through tube B, and up through 
the course D at high velocity, estimated at 1200 ft. per min. 

The course D discharges at a tangent into an outer chamber H, 
which surrounds the chamber A and is concentric with it. The 
material entering chamber // at a tangent circulates and rises 
spirally therein, as indicated by the arrows; it then cascades over 

Fig. 14. 


the upper edge of chamber A, and repeats its course of circulation 
through draft tube B, propellers C and Ci, and chamber //. The 
machine maintains a perfect circulation until all the stock is 
de-fibered. The stock is withdrawn from the apparatus through 
suitable pipes G, which lead from the mid length of the tube B and 
from the bottom of chamber H, as shown. During the feeding of 
the machine, water is supplied through pipe E, and steam for 
heating is admitted at intervals, as needed, through pipe J, 
shown below the course D. 

The de-fibering action is due to the propellers C and Ci, which 
revolve so rapidly that the water is unable to take up the rotary 
speed thereof. Consequently, there are two opposing forces, one 
being caused by the speed of the propeller and the other by the 
inertia of the liquid and stock. In addition to these two 
de-fibering forces, there is another action, which may be described 
as the constructive and explosive effect on the fibers that is 
caused by the difference in the pitch of the two propellers C 
and Ci. The blades of propeller C have a greater pitch than 
those of propeller Ci, which creates a tendency to form a vacuum 
between the two propellers, thus producing what is described 
as an explosive or disintegrating effect on the stock. 

88. De -inking Action. — As to the de-inking action, it appears 
that when wet paper that has been printed with ordinary black 
printers' ink is torn, any ink that is on the line of tear is much 
loosened by the pulling apart of the paper fibers; so much so, in 
fact, that the adhesion of such portions of the ink as remain on the 
fringes of disengaged fibers at the torn edges is much less than the 
normal adhesion of ink to untorn paper. This is probably due 
to the fact that the dry black ink is, physically, a species of film 
or incrustation, which sticks to the paper by reason of the 
adhesive properties of the ink, but which is capable of being 
mechanically loosened by the relative motions of the wet matted 
fibers to which it is stuck. Now if the paper be torn into such 
fine bits that the paper fiber foundation to which each particle of 
ink adheres, is wholly or partly pulled apart, — that is, if the 
paper is completely pulped or de-felted, — then this loosening 
action affects all the ink and renders it easy to remove. 

89. Character of Paper Produced. — Obviously, some types and 
grades of paper stock can be reduced to a pulp more readily 
and with less deterioration than others. A pulp made from a free 


stock, in which the fibers in the original paper making were not 
greatly hydrated, is, of course, felted together rather than stuck 
together, and it is much more amenable to a disintegrating or 
de-felting action than a paper made of over-beaten or slow stock, 
in which the fibers are so much hj'^drated and glutinous that they 
are more or less welded together as well as felted. Extreme 
examples of such papers are pergamyn or glassine papers. 

90. Method of Cooking. — The following statement was 
obtained from a superintendent who had one of these machines 
under his direct care and supervision: 

"We are at present cooking with 5% soda ash, using about 
900 pounds of stock to a batch, and we take about 50 minutes to 
a batch, the density of which is around 5 %. While one batch is in 
process, we are softening another in the tank above, using the 
exhaust steam from the turbine for heating. We raise the tem- 
perature to 160°-180°F., never guessing at it, but always using a 
thermometer, as we get the best results in this way." 

91. Cost of Operation. — This superintendent further states: 
"As to the cost of operation, this is, indeed, a hard matter to 
determine. There is, of course, a saving of about 3% in soda 
ash, as well as the saving of time in washing, which may counter- 
balance to some extent the extra power consumption. There is 
also a big difference in the cost of handling, which is quite an item 
in the vomiting process; in fact, I may venture to state that this 
item was responsible for the advent of the rotary. There is also 
to be considered the matter of the elimination of the dirty mess 
caused by the dripping of the alkali from the boxes, and the 
condensation caused during the cooking process." 

It may be remarked that a 75-h.p. turbine has been specified 
for the satisfactory operation of the process. 

92. Advantages and Disadvantages.— The chief objection to 
this process, which was later raised at the above mentioned mill, 
was its consumption of steam for power and heating. Even 
though the stock traveled 1200 ft. per min. in this machine, it was 
found that dead pockets of stock remained in the machine and 
were not acted upon, which resulted in dirty paper stock; this 
happened from oversight or carelessness in not getting the proper 
density (that is, the correct proportion of weight of papers and 
volume of water) in the tank. If the charge were too heavy on 
entering the machine, only that portion around the central tube 


circulated freely. It has been suggested that the chamber H be 
divided by a helical passage, so arranged that the stock will 
circulate around and around the central tube until it finally comes 
to the top and splashes over into the central tube again, to begin 
its journey once more. If given proper attention by men who 
can regulate the stock to a uniform consistency, this machine 
will produce a product that can be readily washed, screened, and 
made into good paper. The color is a blue white, though not any 
bluer than stock produced by any other mechanical process, 
such as the rotary boiler or any of the later centrifugal-pump and 
tank systems. 

93. The amount of steam consumed is that required to raise 
the temperature of the water in the de-fibering machine to 160°F., 
and for no other purpose ; this represents approximately 300,000 
B.t.u. per 100 pounds of paper. 

94. Layout, and Sequence of Operations. — With the exception 
that no provision for bleaching need be made, and that the boiler 
capacity may be limited to that required for any new furnish and 
for mixing the recovered stock with this new furnish, the process 
just described uses substantially the same auxiliary apparatus 
as would be used in any other process that employs a mechanical 
pulper. The sequence of operations is as follows: According to 
their condition, the papers are first sorted by hand or are dusted 
in a duster and afterwards sorted; the first procedure is used 
when the papers are reasonably clean. The papers are then 
torn and are again dusted in a railroad duster or its equivalent. 
The torn papers are next conveyed upwards by a belt, apron, or 
an air conveyor to a soaking tank having an agitator, in which 
they are thoroughly wet in water at about 160°F. This tank A, 
Fig. 15, is so placed that it can quickly charge the de-fibering 
machine, which works in batches. The water in tank A is 
preferably heated by the exhaust from a steam turbine that 
drives the machine. 

The de-fibering machine B, Fig. 15, is the next element in the 
layout, and its general principle has been already sufficiently 
described. Quick-opening valves must be provided for rapid 
charging and discharging; the time required for these operations 
being, even under the most favorable conditions, a considerable 
proportion of the total time of operation. The pulp from the 
machine passes to the de-inked stock chest C; it requires washing 




only, or, at the most, washing and brushing out in the Jordan, to 
render it suitable for delivery to the stuff chest. The washing 
arrangements, indicated at D, are of the utmost importance for 
removing the loosened ink. The washing layout differs more or 
less in details, according to local conditions; but with an arrange- 
ment of ordinary efficiency, the pulp should be washed for about 2 
hours. The pulp from the final tank will be of 3% to 5% 
consistency; it can usually be pumped to the paper-machine chest, 
if unmixed recovered stock is to be employed ; or it may be pumped 
to the beater or other receptacle, in which it may be mixed with 

Fig. 15. 

any new stock that is to be added. In some cases, it may be 
desirable to brush out the recovered stock in the Jordan before 
sending it to the stuff chest; the piping arrangements should be 
such that this can be done, or the Jordan should be by-passed, 
as conditions indicate. 

Where magazine stock is treated, and sometimes in other cases 
also, it is advisable to pass the stock from the de-inked stock 
chest through a wire catcher, on the way to the washer. The 
washer may be an ordinary flat screen, or a long channel with 
dams, or a deep well. The well is made about 2 feet square and 
25 feet deep, with a partition in the middle that reaches nearly 
to the bottom. The stock, diluted to about 1 % consistency, is 


fed at the top of one side, passes down, drops the pins, and is 
dcHvered near the top again. 

95. Pulping Engine. — A pulping engine, which may be used in 
place of tank A, Fig. 15, in connection with the de-fibering machine 
just described, is shown in Fig. 16. This consists of an eUiptical- 
shaped tub A, with midfeather B, in which the mixture of 

Fig. 16. 

shredded papers and cooking liquor is circulated by a paddle 
wheel W, which makes about 19 r.p.m. The shaft T, which turns 
at 150 r.p.m., is studded with wooden slats *S, which slash the paper 
into fragments and mix them with the liquor. One of these 
engines will hold 1700 pounds of paper, dry weight. 


96. Remark. — During the World War, manufacturing methods 
and processes were given closer scrutiny than at any previous 
time. Work that required manual labor, and which had received 




scant attention up to that time, possibly because of the abund- 
ance of willing workers at low wages, was supplanted by 
machinery and mechanical processes. It is therefore not strange 
that this change also occurred in the processes for the conversion 
of old-paper stock. After the introduction of the de-fibering 
process just described, many applications were made of the idea 
of de-inking and de-fibering paper stock by propelling and circu- 
lating with centrifugal pumps, and by impinging the stock and 
water against a plane surface, a conical surface, a Y or T surface, 
or even against itself, in divided streams. 

97. Improved Cooking System. — One very enterprising mill 
that formerly used the open-tank system has installed a new 
system, which not only saves 50% of the building space, a very 

Fig. 17. 

important item in costs, but also effects a saving of 50% in 
soda ash, and saves the services of 28 men and 30 women. This 
change was effected by using the old tanks in the new construc- 
tion, by installation of the carrier system of sorting, and by com- 
bining what was formerly two sorting rooms and two cooking 
rooms into one sorting room and one cooking room. 

Fig. 17 represents one of four similar cooking tanks, each 10 
feet in diameter and 26 feet in length, suitably mounted on concrete 
piers. Each tank is equipped with a specially designed agitator, 
having arms S, which are staggered on the central shaft and are 
so arranged that complete agitation is assured at a speed of 10 
r.p.m. The agitator is belt driven, and the power is furnished 
by individual 10-h.p. motors; the motor and the agitator drive 
are shown at C and D. Although 10-h.p. motors are used, actual 


tests indicate that 3.5 to 5-h.p, is sufficient; but for safe working, 
it was deemed advisable to have a motor of sufficient power to 
take care of anj^ unusual condition that might develop, as when 
more than 7500 pounds of paper stock is cooked and agitated at 
an increased density. 

98. Method of Operation. — The paper stock, which has been 
previously dusted and shredded into pieces 2 inches square, is blown 
through an 18-inch diameter air duct from the sorting room into 
the charging manhole, shown at M, Fig. 17. To allow the escape 
of air during the charging, a vent N is provided at the other end 
of the tank. A 6-inch water pipe W supplies water to each tank 
while 6500 to 7500 pounds of stock is being introduced. Soda ash 
to the amount of 4%, based on the dry weight of the paper stock 
charge, is dissolved in the soda-ash tank, which is located where 
convenient, but preferably on the floor above the cookers. The 
filling operation takes from 20 to 30 minutes. The temperature 
of cooking is maintained at 200°F., so that the consumption of 
steam is not so great as in the open-tank or rotarj'-boiler processes. 
The steam inlets are shown at H, Hi, H2, and Hz] thej'' are made 
of f-inch piping, reduced from a l^-inch line, on which the valve 
is located. When properly filled with paper and water, the stock 
should have a consistency of 8%. 

99. De-fibering and De-inking. — The de-fibering and de- 
inking of the stock are effected by an 8-inch centrifugal pump P, 
direct-connected to a 40-h.p. motor T. The pump is especially 
designed for this work; it has impellers of sufficient rigidity, and 
is constructed to de-fiber and circulate, without plugging, at a 
speed of 1700 r.p.m. Under the heaviest loads, 36 h.p. is 
required to operate the pump, but the average for 30 daj's was 
only 18 h.p. However, when it is necessary for the pump to 
take up peak loads, such as an extra heavy wad or slug of stock, 
the extra power then needed is available. 

100. The circulation of the stock is effected by means of 3 
8-inch pipe lines F, which lead to the pump inlet, and by 2 
8-inch pipe lines G, which lead from the pump discharge back to the 
cooking tank. The pipes G conduct back to the top of the tank 
the stock that impinges on the T connection, shown at X, where 
further de-fibering takes place. The T connection is considered 
to hasten the preparation of the stock, because of the friction 


and the churning that the mixture of paper and water receives 
at this point. 

After circulating, de-fibering and cooking for one hour at a 
temperature of 200°F., the papers are considered to be cooked. 
By opening valve V2 or V3 and closing Vi, the cooked stock is 
conducted by lines X or L to storage tanks, not shown in the 
figure. From 20 to 30 minutes is required to empty the cooking 
tank. The process consumes 30 minutes for filling, 60 minutes for 
cooking, and 30 minutes for dumping, a total of 2 hours, for 6500 
to 7500 pounds of de-fibered stock. This compares very favorably 
with 5 to 10 hours for cooking 5000 to 6000 pounds of papers in 
the open-tank process. 

101. Fewer Employes than with Open-Tank System. — A 
comparison of the labor employed with the improved system 
with that employed with the open-tank system shows that the 
improved system will do the combined work of two sorting rooms 
used with the open-tank process. Specifically, the old system 
requires 2 rooms for sorting on the bench method; 2 foremen; 
6 carrier men, for emptying barrels onto conveyors; 4 truckers, 
for trucking barrels of sorted papers from benches to conveyors; 
6 cook-room men, 2 to make soda ash and 4 to fill open tanks 
with papers; 4 unloader men, to remove cooked stock from tanks 
with pitchforks; 2 washer rooms, with 4 men in each room; 
24 washer men, 8 men on each tour, to fill washers by forking 
stock from small cars; 60 sorting girls. This shows a total of 54 
men and 60 women. 

The improved system requires only one (1) room for sorting 
60 tons of paper; the conveyor system replaces the bench method 
of handling the papers; and there is required: 1 foreman; 3 
floormen, to truck, lay down, and open bales at the conveyors; 
2 cook-room men, 1 to make soda ash and regulate steam and 
water, and 1 to fill and discharge cookers and to pump stock; 12 
washer men, 4 men on tour in 2 rooms (2 men for each tour); 
30 sorting girls. This shows a total of 18 men and 30 women, 
which is a reduction of 36 men and 30 women as compared with 
the open-tank system. A saving of two-thirds the number of 
men and one-half the number of women formerly required to 
produce the same tonnage, is a marked step forward in lowering 
manufacturing costs. The improved S3'stem is a distinct credit 
to the mill employing it, and unstinted praise is due to the 
superintendent who planned and worked out the process. 



102. Use of Discards. — There is much waste paper collectcHl 
that cannot be made into white paper; to this must be added the 
discards from the sorting processes previously described. Still, 
even this low-grade material is graded for special uses; it is highly 
valued for test board and wrapping paper and in the manufacture 
of kraft paper. Other grades of discards, including old box 
boards, etc., go into pasteboards, card middles -and similar 
papers. Less care is required in sorting discards, and they are 
very often furnished direct to the beaters. 


(1) Describe the cooking engine. 

(2) Would you consider it worth while to recover the chemical used in 
cooking by the process described in Art. 87? Give reasons for your reply. 

(3) Upon what principle does the mechanical de-inking of paper by the 
process of Art. 87 depend? 

(4) If 5 % of soda ash is required for a batch of 900 lb. of papers, what is 
the weight of soda ash required? Ans. 45 lb. 

(5) How is the de-fibering and de-inking of stock effected by the process 
described in Arts. 99 and 100? 

(6) Referring to Fig. 17, explain briefly the operation of the apparatus 
there illustrated. 

(7) Mention some of the advantages that the improved system has as 
compared with the open-tank system. 



103. The Third Step. — The third very important step in the 
treatment of waste papers pertains to the washing and the 
subsequent bleaching of the cooked paper stock. 

104. Washing Engine. — Many different methods are used in 
washing the papers, the most general process being that in which 
washing engines are used. These engines, fully described in 
Section 1, consist of a beater-shaped tub, a circulating roll that 
is equipped with blunt steel knives, but without a bed plate, and 
2 to 4 octagonal-dnmi washing cylinders (see Figs. 1 1 and 12, 
Section 1), 


The capacity of this type of beater is from 800 pounds to 2000 
pounds, the average being about 1600 pounds. The circulating roll 
is raised or lowered by means of a worm gear, in order to varj^ the 
slight brushing action that the stock receives. By installing a bed 
plate and using sharper knives, these washers can be readily 
converted into beating engines. The octagonal-drum washing 
cylinders are constructed on the usual bucket arrangement 
pattern. The faces of the cylinders are first covered with j-inch 
mesh facing wire, and are topped with 60- or 70-mesh washer 
wire. It has been the custom heretofore only to use old Four- 
drinier machine wire for facing the cylinder; but experiment has 
proved that a larger screening surface is obtained by using the 
larger |-inch mesh wire for facing and covering this with wire 
that has been woven especially for the washing of stock. Nickel- 
alloy 60-mesh wires have been placed on the washing drums; and, 
after 1^ years of service, they have shown no perceptible wear. 
They do not require any scouring out with acid, and, barring 
accident from puncture, they should have a much longer life 
than this. The cylinders are equipped with a raising and 
lowering ratchet wheel. 

105. Operations. — After being thoroughly cooked, the papers 
are furnished to the washers, either from the chest C, Fig. 15, or 
as described in Art. 81. Sometimes 2 or 3 quarts of kerosene is 
added; this keeps down the froth and foam that will otherwise 
result when the saponification products (soaps) of the cooking 
process, which have been absorbed by the papers, come in contact 
with the washing cylinders and the rapidly revolving circulating 
roll. When the washer has been completely furnished, the 
washing cyhnders are lowered and the wash water is turned on. 
The amount of water used is regulated to correspond to the 
volume removed by the cylinders; thus a continuous stream of 
fresh, clear water is being added to compensate for the water 
removed, which is laden with the soluble saponification products, 
ink and dirt particles. 

In this type of machine, the fresh water is admitted to the 
stock, sometimes at the bottom of the washer and in back of the 
roll, through a 6-inch pipe. This water dilutes the stock, passes 
up through it and out by the revolving C34inders, and goes to 
waste. Sometimes the water is introduced in front of the roll, 
which mixes it with the stock. It is a slow process of constant 
dilution of the impurities of the cooking action, and a large 


volume of wash water is required. This same volume of wash 
water, if applied to the stock in batches of equal amounts and 
then removed, thickening the stock after each addition of fresh 
water, would greatly lessen the time of washing and would 
produce a cleaner pulp. 

106. Removal of Dirt. — Bj^ the constant dilution of the dirt, 
the amount of dirt remaining in the pulp is gradually lessened. 
This progressive action continues indefinitely; but, even after 
the stated washing period has expired, the stock still contains 
dirt, though, of course, only a very small amount. If at this 
point, a sample of stock be taken from the washer and subjected 
to a stream of fresh water on a small hand screen, the stock will 
brighten up at once to a snow-white color. It is this principle 
that has been taken advantage of in the modern continuous 

107. Removal of Carbon of Inks. — If the paper stock has been 
thoroughl}' cooked, the carbon of the inks is readily removed. 
In the open-tank process, the papers still retain, largely, their 
original flat shape after cooking; hence, on immersing a sheet of 
cooked paper in water, the individual letters of solid carbon can 
be loosened from the paper by gently moving the sheet to and fro. 
The same result is obtained in the cooking engine by the action 
of the roll on the papers, the friction of the papers against the 
sides and bottom of the tub, and against the cylinders; the 
continual rubbing and friction in the mass also further the 
removal of the inks and the formation of an emulsion, which is 
readily removed in the wash water. 

For the first hour of washing, the wash water is very muddy 
and dirty. Continued washing clears the stock; and the color 
gradually changes from the heavy gray tone to a blue white, for 
ledger stock, or to a cream white or ocher tint, for book or 
magazine stock. 

108. Duration of, and Effect of, Washing. — The time required 
for a thorough washing depends on a number of factors. The 
degree of cooking that the paper has received must first be 
considered. If well cooked, the inks will readily emulsify with 
the water; but if the paper has not been completely cooked, the 
ink still sticks, or perhaps it may loosen from the surface of the 
paper and be found later in the finished paper. If the papers 
are dry cooked, no amount of washing will clear the ink from the 




pulp; and after being bleached, this product has a light grayish 
tone, similar to the color of newspapers. 

109. The second factor to be considered is the nature of the 
printing inks. It has been found that ordinary book and maga- 
zine inks and colors are easily washed out; but lithograph and 
label papers that contain waterproof inks and varnishes, present 
greater difficulties. Solid ledger papers arc easilj^ washed out; 
they have received a harder treatment in cooking to dissolve the 
hard sizing, the inks readily emulsify, and a clear, blue-white 
pulp is obtained with about 2h hours of washing, ^ hour for 
bleaching, and ^ to 1 hour for removing bleach residues. 

110. The third factor to receive consideration is the composi- 
tion of the papers to be washed. Long-fibered stock, such as 
writing and ledgers, require a much shorter washing period than 

Fig. 18. 

the short-fibered book stock. The fourth factor is the circulation 
of the stuff in the washer and the amount of water used, which 
influences the washing period. The third and fourth factors are 
really dependent on each other, for the larger the volume of 
water the faster the stuff will circulate, and the larger the volume 
of water used the greater will be the amount of dirt and ink 
removed in a shorter period. 

111. When the paper stock is considered to have been washed 
long enough, a sample of the wash water is taken out and 
examined. If the water is clear, the pulp is ready for bleaching; 
but if the water is still cloudy, if a grayish sediment is noticed, 
the washing must continue until clear fresh water is obtained. 


The first washing will 
generally take from 3 to 
3^ hours for the usual run 
of paper stock, such as 
book and magazine. 

Before bleaching, it is 
well to concentrate the 
stock bj^ shutting off the 
water, but letting the cyl- 
inders run for a time. 

112. Other Forms of 
Washers. — In Fig. 18, is 
shown a machine that both 
washes and concentrates. 
The agitators A keep the 
stock well mixed, and the 
rotating dippers B, which 
are covered with wire mesh 
(60 mesh over 14 mesh), 
take out the dirty water as 
fresh water is added at W. 
On shutting off the fresh 
water, the stock is con- 
centrated, thus saving 
bleach and storage space. 
This washer handles 1500 
pounds of waste-paper 
stock at 3 % to 4 % in from 
2 to 3 hours; it requires 
about 6 h.p. to operate it. 
Each washing cylinder B 
is driven at 8 r.p.m. by a 
worm gear from a shaft E. 
The washed stock is re- 
moved at V. 

113. Another type of 
washer, which is meeting 
with some favor, is a 
slightly inclined, slowly 
rotating cylinder C of fine 
wire cloth, shown in Fig. 19. 




The stock is fed in at one end and is distributed by worm W; 
and as the dirty water drains out, the fibers are washed with 
showers, S, finally emerging at the other end. Very little power 
is required to operate either of the washers just described; but 
practical men consider them to be wasteful of stock. 

114. A new tj^pe of w^asher, which is giving good results, is shown 
in Fig. 20; this washer is very effective for w^ashing thick stock 
rapidly. It is better to wash stock when it is thick, if the water 

Fig. 20. 

can be removed; because, first, there is less stock lost, and, second, 
on account of the small amount of water in the stock, a given 
quantity of water added or removed produces a greater effect. 
S (Fig. 20) is a spout through which dirty water is discharged 
from the hollow shaft T at the center of the cylinder C; D is a 
worm gear for lifting the washing cj^linder by means of cables E. 
This washer was developed as a feature of the beater shown 
in Fig. 3, which is also used as a washer and bleacher; it circu- 
lates stock of unusually high consistency. The small view 
shows the assembled washer, in which G is the gear, belt driven 
from the beater-roll shaft. 



115. A Three -cylinder Washer. — The tendency to take ad- 
vantage of a continuous process has become well-marked in 
waste-paper recovery; and much attention has been given to the 
three-cylinder washer, which authorities regard as the ideal type 
of washing machine. 

An improved washing system for removing ink from cooked 
waste papers is shown in Fig. 21, (a) being a side view and (h) a 
top view. The arrangement consists of a horizontal stuff chest, 
from which the stock is lifted at a uniform rate by means of a 
bucket wheel; a gravitator (or sand trap), the feed to which is 
controlled by a gate; a centrifugal screen, for removing the dirt 
not caught in the gravitator; and a washing machine, which 
comprises three cylinder units. The cylinder in each unit picks 
up a layer of stock in the same manner as a pulp thickener, and 
delivers it to a couch roll, from which it is scraped and passed 
to the next unit. 

The water consumption is small, by reason of the economical 
way in which the water is handled, and 80% to 90% of the ink 
is removed in the first cylinder; this water is not again used for 
washing. The water from the second cylinder is pumped to the 
stuff chest by pump B, where it is used for thinning the stock 
delivered by the buckets. The water from the third cylinder, 
which is, of course, the cleanest, is pumped into the first agitating 
trough by pump A, and is there used as thinning water. The 
only place where clean fresh water is used is in the final washing 
operation, which occurs in the last agitating trough. 


116. Consumption of Bleach. — After washing, the recovered 
pulp is ready to be bleached. For a washing engine of 1600 
pounds capacity, about 60 to 70 gallons of bleach liquor is used for 
book and magazine stock. The hquor should test 6°Tw. at 60°F., 
which is equivalent to about | pound of bleaching powder to a 
gallon of liquor; this amounts to 2 to 3 pounds of powder to 100 
pounds of dry papers. This volume of bleach liquor is allowed to 
act, without heating the pulp, for 30 to 45 minutes, and it should 
produce a snow-white pulp. By taking the chill off the water and 
raising the temperature to about 80° or 90°F. (never higher than 
this), the bleaching operation may be greatly shortened. It has 
been found by trial that a warm bleaching of 15 or 20 minutes 


duration produces very efficient results. It has also been demon- 
strated that, when necessary, — such an occasion arose during the 
World War, — a good bleached pulp can be produced with 0.6 
pounds of bleaching powder per 100 pounds of papers; this 
amount, however, did not give the product the white tone that 
maj' be obtained with a larger consumption. 

After giving the bleach sufficient time to act, fresh water is 
turned in, the cylinders are lowered, and the bleach residues are 
completelj' washed out. To test for the complete extraction of 
the bleach, the well-known test of starch and potassium iodide 
is applied; any chlorine that may be present will be revealed by 
a distinct blue tint. 

117. Bleaching Stock from Special Papers. — For bleaching 
ledger stock, about 35 to 40 gallons of bleach solution for 10,000 
pounds of paper is required, depending on the quality of the paper. 
A thoroughl}' Avashed, solid ledger stock presents a fine blue-white 
appearance, even before the introduction of the bleach solution. 
The mixed ledger, which consists of letterheads, invoices, bills, 
letters, and other similar papers, presents a motley array of 
colors, and it requires a thorough bleaching; but, even then, the 
resulting pulp has a faint tone, dependent on the proportion of 
the strongest colored stock present. However, with the excep- 
tion of the heavier mineral colors, such as chrome-yellows, 
oranges, greens, umbers, and ochers, the colors are easilv removed 
with 40 to 50 gallons of bleach liquor. The bleaching of this grade 
of stock requires from 45 to 60 minutes to obtain the best results. 

118. Variation in Color of Bleached Pulp. — It is quite impos^ 
sible to obtain a strictly uniform color in the bleached paper 
stock. There is such a wide variation in the composition of the 
papers treated, in the man}' different colors present, and the 
variation in the degree of cooking in different parts of the open 
tanks, that this difference is to be expected. A simple expedient, 
used in many mills to obtain a good sample for matching pulp 
from beater to beater, is the following: A sample of pulp is taken 
from the beater and pressed with the hands into a ball, about 
the size of a baseball. With practice, it is very simple so to press 
all the sample balls that each will have very nearly the same 
percentage of moisture. By breaking a ball into halves and 
comparing one half with a half from another ball, a good idea 
of the variation between the two mav be obtained. (When com- 


paring two pulps, it is very important that both have the same 
moisture content.) These balls can be stored on a shelf, marked 
with the beater number and the time, and can then be inspected 
later by the superintendent and foreman, if this is desired. 

It is the practice in one mill to dump the bleached stock, 
together with the bleached residues, into tanks, from whence it is 
pumped up over the screens and back to the drainers (see Fig. 15, 
Section 1), where the stock is allowed to remain until all the sur- 
plus Kquor drains awaj^ and the drainer is filled. In this way, the 
bleach residues have an opportunity to become dissipated while 
oxidizing an}' organic coloring matter that may still remain in the 
stock. The door to the drainer is then opened, the pulp is forked 
into cars or containers, and is furnished to the beaters. When 
taking stock out of the drainers, it is removed in vertical sections, 
so that the various tinted strata of stock may be kept uniform in 
all the beaters furnished. In this way, it is simple to keep the 
shade of the finished paper constant. If the pulp is put into the 
drainer hot, the color will surely deteriorate. It is best to wash 
the pulp in the bleacher. 

119. Use of Wet Machine. — Another method in vogue is to run 
the washed, bleached, and screened stock over a wet machine 
(fully described in Section 1) and into laps of pulp of about 25% to 
30% air-dry fiber; the laps are stored according to the grade of 
paper and the resultant shade. This method of handling 
screened pulp possesses many advantages, and was adopted by 
one of the most modern book-paper mills; it is considered to be 
the most economical and efficient method in use, for the following 
reasons: No elaborate pumping systems or storage tanks are 
required; the loss of time in furnishing the beaters with diluted 
pulp is ehminated; the wet machine can be run independently of 
the grade of stock being used ; the storage of the pulp ahead of the 
beaters, and the possibility of an immediate change from one grade 
of paper stock to another, is a wonderful saving and improvement ; 
the ease and exactness with which the color or shade of the paper 
made on the machine is maintained. 


120. Amount of Shrinkage. — The shrinkage of paper stock on 
washing has always been a stumbling block for many mills that 
have considered the adoption of cooked paper stock for a part of 


their pulp requirements. The exact per cent of shrinkage has, 
perhaps, never been worked out under actual mill-working 
conditions; but it has been estimated to range from 20% to 40%. 
If the paper treated is all coated paper, practically all the coating 
is removed by the de-fibering and washing of the stock, and a 
shrinkage of 40% will probably result, but this does not include 
the loss of any filler that may be present in the raw stock before 
the coating was applied, which amounts to 5% to 8% additional. 
Toward the end of the washing process, that is, when the wash 
liquor is free from dirt and contains only short fibers, it is usually 
considered that an additional loss of 1 % occurs for every added 15 
minutes of washing. Therefore, it is not advisable to wash any 
longer than is necessary to get standard color. 

Machine-made paper has usually received a thorough beating 
or refining treatment. The individual fibers have been drawn out 
and cut up in the beaters, and the refining engine again reduces 
the length of the fibers, when necessary. Then, too, bleached 
soda pulp is quite generally used, much of which consists of fine 
or short fibers. There is no way of preventing the loss of most of 
this fine-filling fiber, if the stock is thoroughl}^ de-fibered and 
washed through the 70-mesh washing cylinder wire. 

121. Limits of Shrinkage. — Numerous ash tests have been 
made on the completely washed and bleached paper stock, and 
the results vary from 2.5% to 4% total ash. When this percent- 
age is compared with the coating ingredients of paper, which 
amount to from 30% to 40% of the weight of the^paper, the 
shrinkage is well nigh startling. 

Books and magazines are usually printed on supercalendered 
paper, which contains 15% to 20% ash. The loss in ash alone 
(not reckoning the 20% of bleached soda fiber that is usually 
present) thus varies from 15%-20% to 2.5%-4% which shows, 
perhaps, the lowest minimum shrinkage. In solid ledger stock, 
the shrinkage is largeh' equivalent to the loss of the heav.y 
sizing, — both animal and rosin sizing, — because the stock is 
usually 80% to 100% rags, which have a long fiber. The remain- 
der of the fiber composition is long-fiber sulphite, which does not 
entail a great loss. 

It is safe to say that the average loss in washing of all kinds of 
paper, well mixed, will be 20% to 30%. 



122. Importance of Screening. — After the old paper stock has 
been washed, bleached, and dumped into storage tanks, it is ready 
to be screened, which is the fourth very important step in the 
treatment of waste papers, although it is an almost forgotten 
detail in some mills. 

123. Common Form of Screen. — The usual screening S3^stem 
in American mills is exceedingly simple and is frequently inade- 
quate. One flat diaphragm screen of six plates, each plate 12 
inches wide and 40 inches long, is considered sufficient to screen 
stock for three beaters of 1000 pounds capacity. About 3.5 h.p. 
is required to drive a screen of this type. The stock is pumped 
up from the storage tanks, at a consistency of about 3.5 ounces 
per gallon (equivalent to 2.66%), onto sand traps. (For disinfec- 
tion of scums, see Section 7, Vol. Ill, and Section 6, Vol. IV, 
under white water.) 

124. Sand Traps. — A common sand trap is 24 inches wide, 30 
to 40 feet long, and 12 inches deep; it is placed 8 to 10 feet 
above the beater-room floor, thus allowing free passage under- 
neath. The bottom of the sand trap is lined with canvass, such 
as old cotton dryer felt from the paper machine, or is fitted with 
cross dams. 

The purpose of these long narrow boxes, or sand traps, is to 
permit the heavier particles of impurities in the washed stock to 
settle out and collect on the rough surface of the dryer felt, or 
behind the dams. The efficiency of the sand traps is dependent 
on the dilution of the stock, the rate of flow over the course, and 
the length of the course. The depth of the stock is about 8 inches, 
the slope of the course is about ^ inch per foot of length, and 
longer the length of the course the more impurities will settle the 

The impurities found in these traps are mostly pins and clips, 
such as are attached to letters, staples and fasteners from book 
backs, rubber bands, bits of rags and strings, sand and heavy 
pieces of grit. A film of fine particles of iron rust is found to be 
covering most of the drj^er felt bottom. 

125. Furnishing the Beaters. — From the sand trap, the stock 
may go back to the chest, or through the screen and to the beater 
or wet machine. When the beaters are ready to be furnished, the 
gate to the screens is opened, and the stock from the sand trap 


flows onto the screen. Here it is diluted with water, to separate 
fibers from impurities, and to enable the stock to be screened 
without clogging the slots and flooding the entire screening 
surface. If the latter should occur, an overflow is arranged to 
take care of the stock, and this overflow returns the stock to the 
storage tanks. 

In most of these single screens, three (3) plates are cut 0.010 
inch and the other three 0.016 inch, or thereabouts. The density 
of the diluted stock as it is furnished to the beater is equivalent to 
1.27% furnish; this means that 1 pound of dry stock is diluted 
with 9.44 gallons of water, since 1 4- (9.44 X 8§) = 0.0127 
= 1.27%. To furnish 600 pounds of dry stock at this dilution, 
the washing cylinders in the beaters must remove 600 X 9.44 
= 5664 gallons of water, which requires from 45 minutes to 1 hour. 

Since 99 % of the fine dirt particles have a diameter smaller than 
0.016 inch, they have free passage through this size of openings in 
the screen. The paper made from this screened stock is sprinkled 
with fine dirt particles, and the quality of the product is thereby 

126. Effect of Poor Screening. — By far the largest percentage of 
the materials retained on the screens consists of small bits and 
particles of broke or paper, which have not been completely 
de-fibered in the washing engine. The amount of this material in 
the screenings has startled many mill superintendents; but, 
instead of remedjdng the trouble, they have side-stepped it by 
increasing the size of the screen cuts, in some instances up to 
0.028 inch. This, of course, cuts down the amount of screened 
undefibered stock somewhat. An attempt is made to clear or 
finish the de-fibering of this stock in the beater and, later, 
by refining it shorter in the Jordan engine. This method may 
work part of the time ; but, occasionally, the increased production 
of the paper machine calls for more stock, in which case, the 
beaters are crowded and cannot condition the stock in the same 
degree. Then, too, when the stock is run long, that is, when a 
good strong-fibered sheet is required, very little beating is 
necessary, except to clear the sulphite or soda pulps used, and the 
Jordan engine action is reduced almost to a bare clearing of the 
stock. The result is that the finished sheet is sprinkled with 
these particles of undefibered stock of varying size. At times, 
they are so much in evidence that they are the cause of the sheet 
breaking down at the wet presses, and offer untold difficulties in 


carrying the sheet over to the calenders, besides being a means of 
carrying ink particles into the paper. The reason for this break- 
ing down is explained by the fact that the particles of broke have 
no felting power, and whenever they are present, they produce a 
weakened spot in the sheet. On going through the calenders, 
these are made transparent, and they stand out quite distinctly 
in the finished sheet. This defect in the finished paper, especiallj- 
in coated paper, results in sheets of lower quality, or seconds. . 


(1) What factors influence the rate and completeness of washing old paper 

(2) About how much bleaching powder is required to bleach, in pulp form, 
100 lb. of dry papers? 

(3) What is your opinion of the suggestion to use a wet machine in the 
handling of cooked waste paper stock? 

(4) What kind of equipment is used in screening waste paper stock? 
Explain the importance of this operation. 



(1) Mention some reasons for the extensive use of waste papers. 

(2) (a) What chemical action takes place in the removal of 
printing ink? (6) What kind of chemical is used? 

(3) What are the four principal classes of waste papers? 

(4) Name the principal operations in treating waste papers for 
paper making, 

(5) Describe, with sketch, one type of waste-paper duster, and 
tell how it works. 

(6) What becomes of the discards from the sorting room? 

(7) Explain the term dry cook and the result of a dry cook. 

(8) If you were planning a mill, would you consider the 
recovery of soda-ash liquor an important factor? Give reasons 
for your answer. 

(9) (a) What are the three principal factors in cooking? (6) how 
does a change in one affect the other two? 

(10) What influence would the cost of power exert in connec- 
tion with the selection of the cooking-engine process? 

(11) (a) If the consistency of a 900-lb. batch of papers being 
cooked is 5%, what is the total weight of the charge? (6) How 
much of the charge is water, allowing for the soda ash 

found in (a)? /18,000 1b. 

^'^- [ 17,055 lb. 

(12) Taking 1 B.t.u. as the heat required to raise the tempera- 
ture of 1 lb. of water 1°F., and assuming paper and soda ash 
to have the same specific heat as water, how many heat units 
will be required to raise the temperature of a batch containing 
900 lb. of paper and chemical, at 5% consistency, from 45° to 
175°F.? Ans. 2,340,000 B.t.u. 

(13) What test shows when bleach residues have been washed 
out of the stock? 

§2 71 


(14) (a) Give maximum, minimum, and average losses in 
washing old paper stock. (6) Mention some sources of these 

(15) (a) Which method of cooking old waste papers is most 
popular? (6) Which method do you consider best? Give 



By Arthur B, Green, A.B., S.B. 

WITH Bibliography 

By C. J. West, Ph.D. 


1. The Preparation and Supply of Stock for the Paper Machine. 
The two operations of beating and refining also accomplish the 
necessary mixing of the various materials that are to go into 
the final paper, and also the necessary reduction of the pulps, or 
fibrous materials, to such a state that they will form themselves 
into a sheet of the desired characteristics. As for the many 
classes of pulps, the sources from which they are derived, the 
processes by which they are extracted from nature, and the 
processes by which they are purified and whitened, these have 
already been dealt with in preceding sections. These processes 
fit the different pulps in various ways for the operation of beating. 
They may or may not be carried on in the same works, or under 
the same management, as the beating and refining themselves; 
but wherever beating and refining are carried on, they represent 
the first step in the actual making of paper, and are always 
included in the same works, and under the same management, as 
the paper machines, which transform pulp into paper. 

Beating and refining are different processes. Where they are 
both carried on, however, they are for the same purpose, and 
constitute two successive steps in the preparation of the stock 
for the paper machine. Refining is not always done; but, with 

Note. — Special acknowledgement is hereby made to Frederick A. Curtis, 
of the United States Bureau of Standards, for valuable assistance in the 
revision and arrangement of the manuscript and in the preparation of the 
§3 1 


very few exceptions indeed, there is always something in the 
nature of beating as the first step in making paper from pulp. 
In some grades of paper, the amount of beating required is so 
slight that the process has degenerated from a highly skilled 
operation to hardly more than proportioning and mixing, carried 
out almost automatical!}-. Newsprint is one of these grades, and 
great tonnage of paper is made every day with no more beating 
than this. Nevertheless, in higher, more expensive, grades of 
paper, it is the beating that largeh' determines the quality and 
value of the final product. 

2. Beating Defined. — Beating is a general term for the 
mechanical treatment given to paper-making materials suspended 
in water, to mix them and to prepare them for forming on the 
paper machine a paper of the desired character. Refining is a 
further mechanical treatment, which usually follows the beating 
or mixing, to complete the preparation of the materials. 

The beater and the refiner are different pieces of equipment. 
There is usually more than one beater for one paper machine, the 
several beaters being furnished and dumped in rotation, all 
discharging to a common chest on the floor below. Thus beating 
is done in batches, and comes under the class of processes known 
as "batch" processes. The chest on the lower floor serves as a 
reservoir from which the beaten stock is pumped up to the 
refiner in one continuous stream, and thus it passes continuously 
through the refiner. Refining falls under the class known as 
"continuous" processes. There may be one refiner for one 
paper machine, or there may be several; in the latter case, they 
may work in parallel for capacity, or in series for maximum 
action on the fiber. 

It is at the beater that the materials which are to impart to 
the final paper its color, opacity, sizing, etc. are added to the 
fibrous pulps. These materials are not pulps; they are non- 
fibrous. Their action and their effect is partly physical and 
partly chemical. 

3. History of Beating. — Not all of the facts are known that 
would be necessary to fix the exact time and place of the first 
use of beating. The verj'- early papers made in China were 
fashioned from fibers of the inner bark of certain trees; and the 
nature of these fibers allowed of enmeshing them into a sheet 
without beating, so long as the work was done by hand and the 


uses of paper were confined to such qualities as could be produced 
in this way. In the eighth century, the art spread from the 
Chinese to the Arabs, then from the Arabs to the Greeks and 
Moors, and reached Europe in the thirteenth century, by which 
time, rags had become so general as raw material for paper as to 
make it certain that some beating must have been done before 
the fibers were ready for the hand mold. 

The early process for reducing cotton rags to pulp consisted 
first of rotting, next washing in open streams in bags, and finally 
pounding, either with mortar and pestle, or on stone surfaces 
with hard wooden implements. The pounding was hand labor; 
but before the eighteenth centurj^, machiner}- was devised for 
doing the pounding; that is, heavy wooden stampers were fitted 
to a row of upright cylinders, or pans, made of wood or stone, 
and by means of trippers attached to a shaft driven by a water- 
wheel these stampers were raised and allowed to fall. This was 
known as the stamping mill. 

These stampers were divided into three groups : The first group 
were shod with heavy iron teeth or nails, to tear the rags ; the 
second group were shod with finer teeth to draw out the fibers; 
and the third group were of hard wood, weighted but not shod, 
and served to bruise the fibers. Fresh running water in the first 
two groups of pans washed the rags through holes in the bottom, 
covered with fine hair-cloth. It is said that this process of 
beating took about 32 hours, and that a mill with six pans could 
produce about 500 pounds a week. Fibers treated by these 
earh' processes went into the paper very much greater in length 
than is the case with any grades of modern paper ; and the sheets 
that have been preserved from early times show remarkable 

4. Invention of the Hollander. — About the middle of the 
eighteenth century one of the great steps was taken in the 
advancement of the paper-making art when the Hollander beater 
was developed in Holland to replace the stamping mill. It was 
claimed that two beaters could be run by the power required for one 
set of stamps. Instead of the row of cylinders or pans, there 
was an open tub, roughly oblong, with ends rounded, and with a 
partition in the center, built parallel with the straight sides, 
allowing continuous flow of the pulp along one side, around the 
end, along the other side, and around the other end. On one 
side of the partition, a roll was mounted on a heavy spindle, 


which extended across the tub at right angles with the long side. 
Under the roll was built a suitable bed-plate; and both roll and 
bed-plate were fitted with bars of metal. Near the roll, on the 
side turning upward, was built a back-fall, over which the roll 
would throw the pulp, and over the roll was a hood to confine the 
splash. Thus, as the roll was turned rapidly in close bearing 
upon the bed-plate, the pulp was propelled around the open tub, 
and passed repeatedh^ under the roll. The Hollander is the type 
of beater in common use today; and in principle it has not been 
changed since its invention, nearly two hundred years ago. 



5. General Considerations. — Although beating, as a necessary 
means of preparation of the stuff, has been in use for three 
centuries or more, nevertheless it is not yet possible to state 
accurately what the beater accomplishes. Brushing, cutting, 
bruising, brooming, hydrating, attrition, are among the terms 
used to describe what happens to the fiber in the course of beater 
treatment, but these are general terms, and it is impossible to 
say how many of them apply to the beating of any particular 
kind of stuff, ^ or in what proportions these various actions take 
place. This phase of the subject will have further treatment in 
later parts of this Section, under the heading Theory of Beating; 
but in considering the various designs of beating equipment now 
to be described, it should be born in mind that none of them can 
be said to be based on accurate knowledge of the beating action. 

The different types of beaters are described roughly in the 
order of the extent to which they are used. The first, the Hol- 
lander, now generally written Hollander, is by far the most 

1 Stuff is the name given to fibrous paper-making materials after mixture 
with whatever non-fibrous substances are used and after beating and 
refining, ready for the paper machine. These materials are in suspension 
in water. The milky mixture flowing out on the paper machine is also called 
stuff, but in this book it will be called stock. It has been modified from 
the beaten and refined state only by dilution with water and with back- 
water from the machine. Pulps ready to furnish to the beater, particularly 
in fine paper mills, are called half-stufif. 



6. The Hollander Tub. — The tub of the Hollander consists 
of an open vessel, built usually of wood or cast iron, the wooden 
construction being shown at A, Fig. 1. The rounded ends of 

the tub, in conjunction with the central partition B, called the 
midfeather, or midboard, form the channel through which the 
stock travels in continuous circuit. In later types, the tub has 
been made of concrete, though this has been used more often 
where the design of the tub is more complex, that is, in other 
designs of beaters. The cast-iron tub is best adapted where heat 
is used in the beater to assist in disintegrating okl-paper stock, 
as in board mills. In mills making fine papers, where color and 


cleanliness are prime requirements, beater tubs are lined with 
sheet copper and beater bars and bed-plate knives are made of a 
non-corroding metal such as bronze. A Hollander beater 
measuring approximately 20 feet long and 9 feet wide, with sides 
about 3 feet 6 inches high, will hold approximately 1350 pounds 
of air-dry stock at a consistency of about 5%. 

An integral part of the beater tub is the back-fall G, shaped on 
one side to conform to the curve of the beater roll, and having on 
the other side a steep slope. The roll throws the stuff over its 
crest, thus forming a head, so that the force of gravity causes the 
stuff to travel away from the roll, around the tub, and thus back 
to the roll again. This travel is called circulation, and stuff 
circulating in the beater tub is said to turn. Due partly to the 
use of short-fibered stocks in recent years, the design of the tub 
and back-fall is receiving considerable study, and many modifica- 
tions are now offered, without departing from the Hollander 
type, to secure more rapid circulation and beating. 

7. In some beaters, as an aid in dumping the stock, water may 
be introduced at the base of the back-fall, as shown at W. For 
certain kinds of stock, especially with rag half-stuff, the beater 
is equipped with a narrow metal box jT, Fig. 1 (6), set in the floor 
and covered with a perforated plate. This acts as a trap for 
heavy particles of metal, dirt, or sand, and is called a sand trap. 
It is cleaned through a small opening to the sewer or by hand. 
Valve y is a sewer connection for cleaning out the tub, and V is 
a valve for emptying, or dumping, the beaten stock to the 
chest. In most cases, these valves consist essentially of a heavy 
metal plate or disk, fitting into the opening with a ground joint. 
In some recent designs, the dumping valve may extend from the 
front side to the midfeather and be so designed that, when the cover 
is raised, it acts as a baffle to deflect the stock to the opening. 

In Fig. 1 (6), it will be noticed that the bottom of the tub is 
flat, and that there is only a small fillet around the bottom of the 
tub and midfeather where it is joined to the sides of the tub. An 
increased speed of circulation and a higher concentration or 
density (consistency) of stock are rendered possible by raising the 
bottom of the back-fall at W higher than the bottom of the tub at 
Y or T, thus permitting a gentle slope for the stock. Lodging 
of inert or dead stock in the corners can be avoided by having 
the bottom of the tub U shaped, as can be readily done with con- 
crete construction. 


8. Beater Roll and Bars. — A heavy spindle C is mounted across 
the tub at right angles to the midfeather, and is supported in 
bearings at its ends, the bearings resting in lighter bars D. To 
this spindle is firmly attached the beater roll R, usually called 
the roll. The spindle and roll are revolved by means of a belt or 
chain drive from a constant speed shaft or motor to a large pulley 
on the back side of the tub. This pulley may be either inside or 
outside the back-side lighter bar. 

9. The typical beater roll is built on three or more cast-iron 
spiders A, Fig. 2, which are keyed to the roll spindle B. The 
spiders are slotted to receive the fly bars C. These bars are 

Fig. 2. 

themselves slotted at both ends, as shown in detail at (6), for the 
hoop or band D by which the bars are usually held in place and 
kept from flying off at a tangent. The bars may be evenlj- 
spaced or set in clusters, the arrangement and number varying 
with the kind of stock to be beaten and the kind of paper to be 
made. Wooden blocks E, cut slightly wedge shape, and called 
filling, are driven tightly between the bars. This filling is made 
from dry, well-seasoned, hard wood; and the water in the tub 
produces a swelling of the wood, which tends to hold the bars 
fast and prevent vibration. There are, however, several methods 
of fastening the bars C to the spiders A. In one case, the bar 
is dropped into a notch in each spider, and is fastened in place by 
driUing a hole in the bar over a pin or lug in the side of the notch, 
the bar being firmly held by pouring in a low melting alloy, or by 
screwing down a wedge. In other cases, the bars are held in 
place by a circular plate or hoop D, which is firmly bolted to the 
outside spiders, and by a driven fit in the slots of the spiders. 


The beater roll R, Fig. 1, is so designed that its width (face) 
nearl}^ fills the space between one side of the beater tub and the 
midfeather. It may weigh, together with the spindle and pulley, 
from 3000 to 6000 pounds and may be revolved at a peripheral 
speed of from 1500 to 2500 feet per minute. The width and 
diameter of the roll depend upon the dimensions of the beater. 

10. In most cases, the beater-roll bars are made of metal; steel 
is in most common use, though bronze, manganese bronze, 
phosphor bronze and manganese steel are also used. A new 
design provides a cylindrical shell with the bars on the outside and 
spiders inside, all cast in one piece, and the bar edges turned 
true. Since different kinds of stock need different beating 
treatment, it is necessary to consider the quality of the bars for 
the particular stock to be beaten. For certain papers where the 
stock has to be beaten very "wet, " such as glassine, or where the 
paper must be free from metal particles, such as sensitizing paper 
and condenser paper, a stone roll is of value, because iron causes 
rust spots, discoloration of tints, etc. This latter type of roll is 
usually made of basalt lava or a mixture of concrete and quartz, 
and may be built up by using narrow blocks that are held to the 
spiders by pins or bolts. Blocks of porous cast iron may be 
employed in the same way. It is possible, however, for a roll to 
be cut out of a block of basalt lava, or to be built up with concrete 
and flint on an old roll, by removing some of the bars and using 
the others for a bond. 

11. In order to prevent loss of the stock that is carried around 
between the bars of the roll, a covering E, called a hood or curb, is 
placed over the roll. This, in part, conforms to the shape of the 
roll and extends back and down the sides, and is firmly bolted to 
the sides of the beater tub. To facilitate the circulation of the 
stock and to prevent if from being carried over the top of the roll, 
a baffle F is attached to the curb to deflect the stock over the back- 
fall. The design of the curb and baffle is of great importance, as 
will be brought out later. 

12. The Bed -Plate. — Directly beneath the roll is the bed- 
plate H, Fig. 1, frequently called the plate; it is set in a chair or 
box by means of wooden wedges accurately parallel to the axis 
of the roll. The bed-plate. Fig. 2 (c) and (d), is made up of strips 
of metal or bars F, set on edge, spaced with wood filling G, and 
firmly bolted together at H. This is shown in large detail at (e). 


These plates may be elbow plates, as shown at (c), or may be 
straight, as shown at (d), and set at a slight angle to the axis of 
the roll, or may take one of numerous other forms. The plate 
and plate box, or chair, are so designed that the plate may be 
removed through an opening in the side of the beater when 
necessar}^ by removing a bolted cover plate. 

13. The Roll-adjusting Mechanism. — In the operation of the 
beater, the only adjustment made after beating begins is the 
raising or lowering of the roll; the mechanism for accomplishing 
this is shown in detail at (c), Fig. 1. The lighter-bar D is pivoted 
at one end at 0; the other end rests on a nut N that runs on a 
vertical threaded rod K, between guides in the lighter stand, 
which keep the nut from turning. At the upper end of the rod 
X is a worm gear L; this engages with a worm on the shaft J, 
which extends across both lighter stands, and is turned by means 
of the wheel M. In this manner, a very minute vertical adjust- 
ment is given to the end of the lighter-bar D. Since the bearing 
that supports the spindle C is at the middle of the lighter-bar, the 
spindle receives just one-half of this adjustment. One turn of the 
hand wheel M raises or lowers the beater roll approximately one 
one-hundreth of an inch. Bevel gears may be, but seldom are, 
used in place of the worm gear and worm. At Z is a spiral cam. 
In case of an emergency, a pull on handle X will raise the roll one- 
half inch or more. 


14. Defects of the Hollander. — There are a number of grounds 
for criticising the modern Hollander beater, among which are: 
larger power consumption; low beating capacity; insufficient 
mixing of the various ingredients of the furnish; large floor space 
required; and lack of close control over the beating operation. 
During the past fifty years there have been numerous attempts 
to improve on the design of the Hollander. These attempts 
have resulted in a large variety of engines of various kinds, which 
are being used to a greater or less degree. Some of the more 
important types will now be described in detail. 

15. The Home Beater. — One of the functions of a beater is 
that of mixing, and the ordinary Hollander beater was found to 
be faulty in this respect. By referring again to Fig. 1, it may 
be inferred from the plan view (a) that portions of the stuff 




flowing next to the midfeather will remain there indefinitely, 
for there is nothing to throw them to the outside; and this will 
be found to be the case. The Home beater (patented in August, 
1886) was designed to overcome this deficiencj% and is illustrated 
in Fig. 3. Instead of running with its top above the surface of 
the stock, as in the Hollander, the beater roll R is submerged, 
and instead of being placed at the center of the tub, it is located 
at one end. The midfeather M, as it approaches the roll, is 

Fig. 3.^ 

turned across the tub at BC, where the top joins the back-fall 
T, which ends in a shoe S that acts as a doctor, to deflect the stock 
from the roll. Thus the stock is carried between the roll R and 
the bed-plate P, thence around and over the roll, where it is 
deflected by the shoe S, and is sent back on the other side of the 
midfeather and under the back-fall at AB, to the roll again. 
The back-fall creates the head that forces the stock around the 
tub. As the stock nears the roll, the channel through which it is 
traveling becomes wider and shallower, finally reaching a width 
equal to that of the roll. Those portions of the stock, therefore, 
which approach the roll from a position next to the midfeather, 
actually return from the roll in a position next to the outside of 


the tub. This action may be readily observed in a mill when 
the beaterman puts in the colors. 

As the head of stuff over the shoe may, under some conditions, 
be considerable, the return side of the tub is covered with stout 
plank E, which extends nearlj^ to the end of the midfeather, 
where the sectional area of the channel again becomes normal. 
The roll is carried and adjusted by the same type of mechanism 
that is used with the Hollander. 

16. The Umpherston Beater. — Another deficiency of the 
Hollander beater is the large floor area required to operate 

Fig. 4. 

it. There have been many attempts to improve upon the 
Hollander in this respect, notably in the Taylor and the 
Umpherston beaters. The Taylor is rarely found in use now. 
but the Umpherston is on the market, and is not uncommon, 




In both of these types, it is sought to economize floor space bj' 
circulating the stock, not in a horizontal path, but in a vertical 
one, passing downward through the floor and up again on the 

The Umpherston beater is illustrated in Fig. 4. The tub, 
made of cast iron, is in the form of a shell, in two parts, set into 
the floor up to the level of the flanges F, where the two halves 
of the tub are fastened together. The midfeather M and the 
back-fall B are one piece, set in a horizontal position; and in the 
same casting is carried the chair for the bed-plate P. The stock 
is furnished at A and dumped through the spout at D. The 
cast-iron fitting through which the dumping is effected is provided 
with a packing gland G, through which runs a vertical spindle. 
The spindle operates a cap, or plug, fastened to its upper end, 
and raises the cap, to allow the stock to drop; it is also connected 
by a lever to a handle above the floor, which operates the valve. 
The roll R is shown conventionally. 

17. The bed-plate is set in a cast-iron chair, or box, as in other 
types of beaters, and is driven to position between wedges; 

it is removed for repairs, or 
raised, through a cover plate 
on the side of the tub, just 
above the juncture of the two 
halves of the tub casting. The 
lighter mechanism, unlike the 
Hollander, does not have a 
lever, but consists of an L, or 
boot-shaped support T, Fig. 5, 
with the roll-bearing box B 
resting on the horizontal part 
(toe) of the boot. The ver- 
tical part may end in the form 
of a screw running in a composition-metal nut at the top. This 
nut is geared to a hand-wheel shaft, extending across the tub, by 
means of which, both ends of the roll spindle are adjusted exactly 
and together, similar to the hand-wheel mechanism of the 
Hollander. This mechanism is housed in a casting, also L- 
shaped, which rests on a bracket cast on the side of the tub; it is 
provided with a locknut adjustment, by means of which the 
roll may be alined horizontally. In Fig. 5, a variation of this 
arrangement is shown. Here the vertical leg E has a heel H 

Fig. 5. 


resting in a socket, and is connected at the top, by a pin joint, 
to a casting F. The latter is drilled and tapped (threaded) to 
take the screw M, which has bevel gear Gi at the other end, and 
which is driven by G2 on hand-wheel shaft N. Any movement 
of M will pull or push the top of E, which is the long arm of a 
bell-crank lever, and thus raise or lower the roll-bearing box B. 
A stop screw S fixes the lowest position of 5; it can be adjusted 
to meet the conditions of stock and the wearing of bars. 

18. The Miller Duplex Beater. — Inventors have endeavored 
many times to increase the amount of roll action possible during 
one circuit of the stock around the tub. Engineers have fre- 
quently tried to compute the effective work done by the roll on 
the stock, by multiplying the number of bars in the roll by the 
number of knives in the bed-plate, and multiplying this product 

Fig. 6. 

by the number of revolutions per minute of the roll, the final 
product being the total number of cuts per minute. However, 
a large part of the power used in driving the ordinary type of 
beater is required to propel the stock around the tub, and only 
a smaU proportion is required to overcome the friction of contact 
between the roll and the bed-plate; therefore, it is urged that 
more cutting action in the same capacity of tub will result in a 
more efficient beater. 

A recent application of the foregoing reasoning is embodied in 
the Miller duplex beater, which is shown in Fig. 6. Its opera- 
tion is similar in principle to that of the Umpherston, except that 
a second bed-plate is placed above the roll. The lower bed-plate 
Pi is, of course, fixed in position, while the hghter mechanism, in 
addition to carrying the roll itself, also carries the upper plate P^. 
The adjusting device that raises and lowers the roll is so designed 
as to move the upper plate Pi exactly twice as far; thus the 
distance between the roll and the lower plate is always equal to 
the distance between the roll and the upper plate. Springs are 




used to take up any shock on the upper plate in case of hard 
objects passing through. The dumping valve D is similar to 
that of the Umpherston. 

19. The Marx Beater. — The Marx beater, shown in Fig. 7, 
is in line with the effort to obtain more roll action for the same 
capacity of tub. Here, however, there are two complete sets 

Fig. 7. 

of roll and bed-plate, each with its own hghter equipment; and 
to accommodate them, the tub is designed in the form of a 
circuit channel, the midfeather being changed into an enclosure 
for the inboard lighter sets and pulleys. An advantage derived 
from this design is that one set of roll and bed-plate can be 
made of one type and the other set of another type, thus produc- 
ing two separate kinds of action on the stock in a single circuit 
around the tub. In Fig. 7, roll Ri is a stone roll, while roll R2 
has metal bars. 


The lighter equipment, shown in detail at (6), Fig. 7, embodies 
a refinement in the adjustment of the roll, which is effected by 
a lever A and counterpoise TF. By sliding the weight W outward 
on the lever, more of the weight of the roll can be counterbalanced, 
thus leaving less of its weight to act on the stock. It is to be 
noted that in duplicating the roll and bed-plate, it is also neces- 
sary to duplicate the dumping outlet 0, because there are two 
low places in the bottom of the tub, one in front of each roll. 

Fig. 8. 

The roll, if made of stone, may be turned from a sohd block 
and scored to form bars; or wedges may be set in special disks 
or headers. The selection of the stone is very important. Basalt 
lava is often best; it has small cavities, whose edges cut and do not 

20. The Rabus Beater. — The Rabus beater, shown in Fig. 8, is 
similar in arrangement to the Home beater. The tub, however, 
is modified into the form of a closed circuit, with open mid- 
feather, in the effort to obtain more rapid circulation of the stock 



with the same expenditure of power. The channel is deeper, and 
is shaped to facihtate the flow of stock and prevent lodging. 
Note that the stock flows in a direction opposite to that in the 
Home beater, Fig. 3. 

21. The Niagara Beater. — A very recent design, which has met 
with great success on many grades of paper in reducing the power 

Fig. 9. 

expenditure in beating, the time required, and the floor space, 
as compared with the Hollander, is the Niagara beater, shown in 
Fig. 9. Great attention has here been paid to the design of the 
channels through which the stock must circulate. A U-shaped 
bottom and a very high back-fall are employed; and there is a 


marked difference between the width of the channel at the front 
side and at the roll side of the tub. Although the roll is not 
submerged, it has, nevertheless, the effect of being submerged, 
by reason of the great height to which it throws the stock over 
the back-fall, K. The marked reduction in time required for 
beating with this beater is attributed to the improved circulation 
of the stock, which not only allows the roll to treat the same 
portion of the stock more frequently but also renders a con- 
siderable portion of the power used in circulation available 
for mechanical work by the roll and bed-plate on the stock ; and 
this is accomplished with an unusually high consistency of stock. 

22. The Emerson Beater. — Another method of obviating the 
tendency of the stock that lies next to the midfeather to remain 
there is the device employed in the Emerson beater. The 
midfeather is made in two parts, exactly alike, set parallel to each 
other in one tub, with space enough between them to place the 
roll. The roll is mounted on a spindle that spans the entire tub, 
as in the case of the Hollander, with the lighter equipment 
standing outside of the tub. Thus, the stock passes under the 
roll in this central channel, over the back-fall; it is divided at 
the rear end of the two midfeathers, one half passing to the 
right and the other half to the left, in two separate channels, to 
the front of the engine, where the two streams reunite in the 
central channel and again approach the roll. In the Emerson 
beater, the tub is more nearly oblong in plan. 

23. The Stobie Beater. — Probably the modern development of 
short-fibered chemical and mechanical wood pulps has brought 
forth no more bold departure from precedent, in the matter of 
design, than the Stobie beater. This apparatus could not be 
employed on long-fibered stocks, but it applies admirably to such 
materials as sulphite, kraft, soda and groundwood fibers. 

An open-tub beater is used as a container in which to mix the 
ingredients of the furnish, and to break up the laps and dry broke ^ 
that may be used. The mass is then dropped into a chest, which 
is provided with a good agitator. Drawing from the bottom of 
this chest is a three-stage centrifugal pump, which is capable of 

' Broke is paper that has been discarded anywhere in the process of 
manufacture. Wet broke is paper taken off a wet press of a paper machine; 
dry broke is made when paper is spoiled in going over the dryers or through 
the calenders, trimmed off in the rewinding of rolls, or trimmed from 
sheets being prepared for shipping. 


delivering the stock above the top of the chest to three or four 
fire nozzles, arranged in a battery and shooting horizontally, 
at a pressure of about 75 pounds per square inch. Before them 
is arranged a plate, the surface of which is serrated (something 
like the tread of an iron stair), and which is set at an angle that 
will deflect the stock downward again into the chest. In this 
manner, the stock is circulated from chest to pump, to nozzles, 
to plate and back to chest for a given period of time. It is then 
dehvered to the paper-machine chest without any further 
refining. Stock at a consistenc\'^ of 2.5 % is circulated for a period 
of 20 minutes, the nozzles acting under a pressure of 75 pounds 
per square inch, the serrated plate being set at an angle of about 
45 degrees. These conditions are roughly the average for a 
hard all-sulphite paper. 

In power requirements, the pump is about equivalent to a 
large Jordan engine; and there is also to be added the power 
required to drive the breaking engine, in which, however, it is 
not always necessary to set down the roll. On rough computa- 
tion, the Stobie beater would require about 120 horsepower-hours 
per ton of paper on a grade that would require about 370 horse- 
power-hours per ton of paper when beaten according to the usual 
methods; this represents a power saving of about 67%. 

24. Besides the saving in power, Stobie's process affords the 
opportunity of gaining close control. Once the consistency has 
been governed, there are only four other variable factors: the 
pressure; the character of the plates; the angle at which the plates 
are set; and the length of time of beating. The character of 
the plate and the angle at which it is set may be fixed 
mechanically, and a recording pressure gauge will show both the 
pressure and the time. If, then, the management specifies 
what nozzle pressure to use and for what length of time the 
process must run on each furnish of stock, there is practically 
absolute control, with consequent uniformity of results, the 
only remaining condition that may vary being the characteristics 
of the raw stock. An accurately conducted beating process, 
however, tends to reveal such changes in the raw stock as may 
occur, and the management has the best opportunity to compen- 
sate for these, by making proper changes in the instructions 
governing the pressure and the length of time. In this way, 
it is possible for one good man on each tour to attend to all of 
the beating for a very large mill. 


To just what extent this apparatus will apply to different 
classes of short-fibered stock and to different requirements as to 
finished paper, remains to be seen when mills in other lines of the 
industry are permitted to experiment with it. Certainly the 
elements of which the Stobie beater are composed, are capable 
of great modification, to suit different conditions; and this 
beater therefore represents, perhaps, the most hopeful, as well as 
the most radical development in beating equipment to date. 


26. Necessity for Exercising Care. — The very simplicity of 
the design and construction of most types of beaters tends to 
promote laxity in caring for them. This is particularly true in 
mills making coarse boards or saturating felts; and it applies 
also to mills using waste paper and cheap pulps, where the 
beater acts largely as a mixing vat and the roll is not lowered to 
any extent. But it is in mills making fine papers, where the 
beaters are carefully handled, that particular attention must be 
paid to the condition of the fly-bars and bed-plate, the adjust- 
ment of the deflector in the curb, cleanliness, power con- 
sumption, and the condition of the roll-adjusting mechanism and 

26. Grinding of the Roll Bars. — During beating, the fly-bars 
of the roll and the knives of the bed-plate become worn, and thoy 
must be replaced from time to time. It has been shown that the 
bars may easily be removed from the roll; also that the bed-plate 
may be taken from the beater by removing a plate on the side of 
the tub, taking out the wedges holding the chair or box, and 
sliding the plate out. It is sometimes possible to continue to use 
a worn roll and plate by chipping out some of the wood between 
the bars, and thus have pockets deep enough between them to 
produce the necessary circulation, 

27. After the roll has been filled, it is necessary to grind it to a 
true fit with its bed-plate; and the grinding must be done in such 
a manner as to insure that all bars come into contact throughout 
their entire length. The old way of doing this, which is still to 
be preferred where the finest beating is to be done, is to place in 
the tub, in front of and behind the roll, suitable dams. The 


space between the roll and the dam is filled with fine, sharp 
sand, and the roll is turned against the bed-plate in this fine sand 
until the sound it makes and an inspection of the bars indicate 
a perfect fit. During this operation, enough water must be 
added periodically to prevent the development of too much heat. 

A quicker method, but not so satisfactory for fine beating, is 
to remove the roll, mount it in a lathe, and bring the bars to their 
proper form by means of a grinding wheel. The bed-plate is 
then placed under a grinding wheel, which swings over a radius 
equal to that of the roll with which it is to run. In practice, 
this method is available only to the larger mills, because in 
smaller mills it is costly to remove the roll from the beater for 
refilling. It is generally desirable to grind a new roll also, except 
where it is to be used for coarse boards or felts. 

In addition to the wearing down of the bars during beating, 
there is a change in the degree of sharpness or dullness of the 
bars, which is a very important factor in many classes of 
paper. Blotting paper requires sharp bars, whereas glassine 
and high-grade bond and ledger papers require dull edges on 
the bars. 

28. Cleanliness. — In mills making white or colored papers, it 
is of importance that the equipment should be periodically 
washed, to remove dirt and other material that would show up in 
the finished paper. When running colored papers, the coloring 
is commonly done in the beater; and to the beaterman falls the 
task of seeing to it that every beater is washed free from stock 
carrying any color, before furnishing stock for a different color. 
This precaution is not restricted solelj'' to the beater, but applies 
also to all the equipment through which the stock passes — head 
boxes, spouts, chests, pumps and refining engines. Moreover, 
beating equipment ought never to be shut down for more than a 
day without thoroughly washing out every part of it. The 
stock that adheres to the beater becomes very hard on drying, 
does not readily recover its water, and comes off in lumps, which 
will reach the paper machine wire to some extent and cause 
trouble and lumps in the paper. The fine-paper mills have a 
complete wash-up of the entire beating equipment at frequent 
intervals, regardless of any shutdown or change of color. In 
some cases, the spouts are constructed entirelj'^ of copper, with 
many hand holes; the chests- are surfaced with the best glazed tile 
lining and all inner surfaces are kept clean. Sand traps and 


pockets of all kinds should frequently be cleaned, to remove 
heavy particles of dirt and metal. 

29. Use of Paint. — When the parts of wooden tub Hollander 
beaters are delivered by the builders to the mill, the metal parts 
are coated with white lead, and the wood parts, including the 
filling strips between the roll bars, are heavily primed with oil 
and white lead, for the purpose of preventing rust of the metal 
parts and the shrinking or checking of the wood parts. The out- 
side of tub and curb are commonly finished with shellac and 
spar varnish; the inside of the tub may be finished with oil. In 
fine mills, during the periodic shutdown for cleaning, say once a 
year, the inside surfaces of the beater, including both roll and bed- 
plate, are both thoroughly scoured free of the thin film of slime 
that collects from the stock; and the end spiders, or heads, of the 
beater roll are thoroughly scraped, to remove slime and rust, and 
are coated with red lead or some other anti-corrosion paint. It is 
claimed that aluminum bronze, properly applied, gives excellent 
service. Where cleanliness is of prime importance, it is generally 
the custom not to allow the stock to come in contact with wood 
or with a corrosive metal at any time ; and in these cases, the wooden 
tub is lined with a non-corrosive sheet metal (copper), brazed at 
the joints, and roll and bed-plate are equipped with bronze bars. 
The roll heads are cast in bronze, or if cast in iron, they are 
sheathed as is the wooden tub. To make clean paper, the beater 
room must be kept clean, and the beaters, chests, etc. thoroughly 
cleaned periodically. 

30. Swelling of Wood. — The tightness of the wood tub, and 
the accuracy of form of the beater roll, depend upon the swelling 
of the wood due to moisture. It is the swelhng of the wood strips 
between beater roll bars that holds the bars fast. This swelling 
must have taken place before the roll is finally ground ; for, how- 
ever accurate the roll may be when dry, it will be thrown out of 
round when the wood strips are swelled. Moreover, a roll once 
put into service and ground to fit its bed-plate, cannot be allowed 
to dry; because, on putting it back into service, although the wood 
strips will swell again, they will not restore the roll to its former 
shape. If allowed to dry, it would be found seriously out of 
round and would have to be reground. Accordingly, a beater 
when shut down must have water in it, and the roll must be turned 
over once or twice each day to keep it in shape. 




31. Other Equipment Necessary. — In the preparation and 
supply of stock or stuff to the paper machine, there are several 
different types of equipment necessary besides the beaters. Since 
the beater has to be alternately filled (furnished) and discharged 
(dumped), which is an intermittent process known as the batch 
process, and since the paper machine, on the other hand, draws 
stock continuously, there must be in practically every installation, 
several beaters feeding a single paper machine. The intermittent 
supply of stuff from the beater is converted into a continuous 
supply through storage tanks (chests) and pumps. Gravity is 
taken advantage of wherever possible; but in practically all 
mills, stuff pumps are used for forcing the stock from the chests 
to the refining engine or to the paper machine. In addition to 
the above, there are auxiliary apparatus of various kinds, which 
are used in connection with beaters, or are used for regulating 
the flow of stock. 

32. Mixing Chest. — Mills making low grades of paper, as 
for example news, use their beaters for scarcely any other purpose 
than to break up the laps of stock or to pulp the dry broke. 
They usually depend on the refining engine to prepare the stock 
for felting on the paper-machine wire. In some cases, the stock 
comes from the pulp mill in slush form, and is mixed in a tank or 
chest before being pumped to the refining engine. One form of 
such a mixing chest is shown in Fig. 10. The peculiar feature 
of this chest is the cyhndrical coffer A, placed inside and rigidh^ 
supported from the walls of the chest. The agitator B is driven at 
a high speed, and is designed to propel the stock downwards. 
The bottom of the chest is deeply dished. Thus the stock receives 
more or less violent agitation and a thorough mixing. The 
stock outlet is at 0, and the washout is at W. 

33. Stuff Chests. — Stuff chests, shown at E and J, Fig. 20, 
are built in manj^ different ways. The early designs were the 
same as an ordinary water tank, cylindrical in form, and made up 
of two heads, and with straight planks and staves, held tight to 
the circumference of the heads by iron hoops. Although this 
kind of chest is still very often found, it is being replaced by more 


carefully designed chests; partly because chests of larger capacity 
are now demanded in mills of large production, and partly 
because the different character of modern paper stock requires 
somewhat closer attention to the design of chests and to the 
materials of which they are constructed. 



Fig. 10. 

34. A very good type of stuff chest is shown in Fig. 11. This 
is a so-called vertical chest, built in cylindrical form, of concrete 
or brick, and lined inside with glazed tile. To set the tile lining 
properly requires the highest degree of skill on the part of the 
mason ; because the surface has to be accurately smooth, and all the 
joints must be perfectly pointed with cement. In mills using a 
great deal of clay in the stock, this feature is especially important. 
The base of the chest has a fillet on the inside, to prevent the 




lodging of dead stock at the juncture of side wall and bottom; and 
the bottom itself is dished instead of being flat. Both the service 
outlet and the sewer outlet are placed near the center of the dished 

Fig. 11. 

bottom, so all the stock can be run out when changing orders, 
changing colors or shutting down. Similar chests are often 
made of wood preferably, cypress. 


A vertical shaft A, whose center Hne coincides with the center 
Hne of the chest, turns in a step bearing L, usually made of 
lignum vitse and set in the bottom of the chest. To this shaft is 
attached a series of agitator arms B, so designed as to throw the 
stock outward and upward along the wall of the chest. At a 
higher point on the shaft A is another set of arms E, designed to 
throw the stock downward at the center. Arms E are in use, of 
course, onh' when the chest is filled to their level or higher. A 
cup D catches the excess oil that falls from the upper bearing of 
the vertical shaft. 

Supported over the chest on a bridge tree is a shaft S and pulley 
P, with or without a clutch K, which drives the agitator through 
a cone pinion and crown gear C. For a chest 12 feet in diameter 
and 10 to 12 feet deep, an agitator of this type should be driven 
at about 27 r.p.m., and will require from 6 to 8 h.p. In mills 
making a good grade of paper, it is verj-- important to have the 
chest well covered, as a guard against dirt. Somewhere in the 
top, however, there is provided a peep hole, illuminated with an 
electric lamp, so the beaterman on the floor above can see at all 
times how full the chest is, and whether or not the agitator is 

35. Horizontal Chest. — The vertical chest shown in Fig. 11, is 
preferred by some to the horizontal chest shown in Fig. 12, but 

SecVion A-A 

Fig. 12. 

the latter type is by no means uncommon, and it may be required 
when there is but little head room. As illustrated, it is a cylin- 
drical wooden tank, built on its side. The same type is also 
built of brick or concrete, without the upper part being arched 
over, the sides being carried straight up from the level of the 
center line of the agitator shaft. The agitator shaft S is hori- 




zontal; it carries arms B and is driven from the outside. T is a 
support for the center bearing. It is claimed that the horizontal 
chest produces more uniform and quicker mixing. 

36. Packing Gland. — Fig. 13, shows a typical packing gland, 
in which the agitator shaft runs; it is adapted to either vertical 
or horizontal stuff chests, and prevents leakage. Such a gland 
is used in vertical chests when the driving gear is below the chest; 
otherwise, the bottom of the agitator shaft is usually set in a step 
bearing in the bottom of the chest. 

Tap Bolts- 




^Bottom of vertical 

or side of horizontal 


Fig. 13. 

37. Stuff Pumps. — The work done in lifting paper stock 
from a lower to a higher elevation, as at points F and K in Fig. 20, 
requires that the amount of stuff delivered per minute shall not 
vary, whether the pump is drawing from a full chest or from one 
that is nearly empty; under such conditions, the plunger pump 
is used. Each stroke of a plunger pump — sometimes called a 
displacement pwjip— admits and discharges a fixed volume of 
stuff. Plunger pumps are designated as single (or simplex), 
duplex, or triplex, according as they have one, two or three 
cylinders. Pumps of various types are described in an article 
by E. F. Doty, Paper Trade Journal, beginning Jan. 4, 1922, 
and Pulp and Paper Magazine of Canada, beginning Jan. 5, 1922 
(see also Vol. V). 

38. A duplex plunger pump is represented in Fig. 14. It is 
driven through pulley P, either with or without a set of reducing 


gears, according as the duty of the pump is low or high. By- 
means of a crank and connecting rod T, a long plunger K is 
moved up and down in the cylinder C, one on each side of the 
pulley. As the plunger rises, it leaves a partial vacuum behind 
it, which draws the stuff into the cylinder at the suction (or 
intake) end. When the 
plunger reverses its move- 
ment and begins to descend, 
it closes the suction valve and 
forces (discharges) the stuff 
in the cylinder through the 
delivery (discharge) outlet. 

39. The manner in which 
the plunger pump works is 
shown in detail in Fig. 15, 
which represents a section 
through the cylinder of a 
simplex pump. The plunger 
A is long and hollow^; and 

Fig. 14. 

Fig. 15. 

when in its lowest position, as shown, it occupies almost the entire 
volume of the cylinder D. The plunger runs through a packing 
gland G at the top of the cjdinder. Directly below the cylinder 
is a hollow ball F, which acts as a valve, admitting stuff to the 
cylinder as long as the plunger moves upward. As the plunger 
starts to rise from its lowest position, it reduces the pressure 
behind it. The difference in pressure on the top and the bottom 
of the ball causes it to rise from its seat, and causes a flow of 


stock upward, following the plunger. When the down stroke 
begins, the pressure on the top of the ball is greater than that 
beneath it; this forces the valve (ball) to its seat, which prevents 
the stuff from flowing back through the inlet pipe. As the 
plunger descends, the pressure increases; the stuff confined in 
the cylinder must go somewhere, or the plunger must stop, or the 
cylinder must burst; so the stuff flows through the discharge 
connection B, lifts the discharge valve (ball) E, and discharges 
through a pipe connected at C; this action continues until the 
plunger has reached the full limit of its down stroke. When 
the plunger again begins to rise, the pressure above valve (ball) 
E is greater than beneath it; this causes E to close (fall back to its 
seat), and keeps the stuff from flowing back from C; valve F 
rises, and the cycle is repeated. Both ball valves are made 
accessible by handholes, covered by plates H, which are held 
tight against gaskets. 

40. Caution. — In operating a plunger pump, always keep in 
mind two very important precautions: first, never allow it to 
pump against a closed valve, for, otherwise, something must 
give way and serious damage must result; second, be sure that 
the stuff being pumped is free from foreign substances, such as 
small pieces of wood or rubber hose, which may get under the 
balls and cause the ball valves to leak. 


(1) (a) What were the early methods of beating? (b) When was the 
beater invented? 

(2) What processes are carried out that are incidental to beating? 

(3) Suppose the roll spindle, Fig. 1, to rest at the center of the lighter bar 
D; if the rod K has a thread of j-in. lead, the worm gear L has 20 teeth, and 
the hand wheel M is given one-sixth of a turn, how far is the roll lifted from 
the bed-plate? Ans. yj,^ in. 

(4) Explain the circulation of stock in the beater. 

(5) What are the objections to steel bars, and what other materials are 
used ? 

(6) In what respects do the Home and Umpherston beaters differ from 
each other and from the Hollander? 

(7) Describe a type of beater other than those mentioned in the last 
question, and give its advantages and its disadvantages. 

(8) Would you prefer a vertical or a horizontal stuff chest, and why? 

(9) (a) Why is the plunger type of pump well suited to pumping paper 
stock? (6) What precautions must be observed in operating it? 


(10) What must be the minimum diameter of a cylindrical stuff chest 
under the following conditions? It is to hold two beaters of stock, each of 
which is to dump 1200 lb. of bone-dry stock, mixed with sufficient water 
to make its consistency 3% (see Art. 69); the total head room in the base- 
ment is 15 ft. 3 in.; 18 in. must be left under the bottom of the chest for 
piping, and the stock level must be kept at least 18 in. from the top of the 
chest; the bottom of the chest is 4 in. thick, and the weight of a cubic foot of 
stock may be taken as 62.5 lb. Ans. 12 ft. 4 in. 


41. Regulating Box,— The stuff pump must deliver a constant 
quantity, equal to the maximum amount of stock required for 
the machines. Provision must be made for times when less 
than maximum capacity is wanted. 
In Fig. 16, is shown in detail a very 
simple form of regulating box, which 
may be used as at G, Fig. 20. This 
is simply a wooden box A, divided 
nearly in halves by a partition B. 
The part ah is cut lower than the 
part he, and the opening thus left is 
provided with a gate G, which can 
be adjusted by means of screw S, to 
close all or a part of the opening. 
The top of the gate G may be raised 
higher than the partition at he. The 
partition D is higher than he, but 
lower than the top of the box. When 
more stock is pumped into the box at 
E than is wanted in the Jordan (or 
the paper machine), the gate is raised 
until the excess stock passes over he 
into compartment 7*^, then down pipe 
H, and back to the chest. If the 

stock is too thick, water may be added through pipe W. There 
are many designs of regulating boxes; some others are described 
in the Section on Paper-making Maehines. 

Some mills even have consistency regulators, so the stock 
pumped to the Jordan regulating, or flow, box is of very nearly 
constant density. A complete description of such an automatic 
regulating device may be found in Section 7, page 57, of Vol. Ill; 
it is briefly described in this Section in Art. 81. 




42. Washing Cylinder. — It is sometimes necessary to wash 
stock in the beater; or to increase its density (thicken it) by 
removing water. This is done commonly by means of a washing 
cylinder, such as that described in Section 1, Preparation of Rag 
and Other Fibers. This attachment is a set of scoops in a wire 
casing, which can be raised and lowered; it is caused to rotate, 
so as to dip up water without removing fiber. 

43. String Catcher. — Fig. 17 represents an apphance for the 
open-tub beater, the object of which is to rid the stock of long 
strings, such as may be found in various classes of rag and rope 

Fig. 17. 

stocks. The string catcher is mounted in the tub, in front of the 
roll, and acts in the same manner as the racks at the inlet of a 
water wheel. The arms A are mounted on a shaft B that spans 
the tub, and they are raised by means of a hand wheel C, geared 
to a quadrant D. The arms are held in position, when down, by 
a pawl E, which engages with a ratchet F, which is on the same 
shaft as the wheel. The lever L, attached to the shaft B, carries 
a weight that acts as a counterbalance to the arms A . 

44. Continuous Beater Attachments — Shartle Attachment. — 

This consists of a casting that was designed to replace the back- 
fall of the ordinary Hollander beater. The surface toward the 
roll is perforated, and means are provided for the discharge of 
stock from under this back-fall. Assuming that the object of 
beating is to reduce the stock in fineness, or length, the perfora- 
tions are so arranged that when the desired fineness has been 


reached, stock will begin to pass the holes and on to the spout; as 
fast as this occurs, fresh stock can be added to the beater, which 
is thus converted from a batch to a continuous machine. 

45. Bird Attachment. — Similar in principle to the Shartle, is the 
Bird continuous beater attachment, a perforated revolving drum 
being substituted for the perforated face of the back-fall. The 
drum is mounted in the channel of the tub that is opposite to 
that of the beater roll; it has perforations distributed uniformly 
over its face and over the end that faces the midfeather. The 
other end of the drum is open; and the stock that flows into the 
drum through the perforations is discharged through this end 
into a spout, which extends through the side of the tub, to a box 
outside the beater; the level of the discharge is governed by an 
overflow dam. The rate of discharge is governed by two factors : 
The size of the perforations relative to the fiber-reducing power 
of roll and plate; the difference in level between the stock circu- 
lating in the tub and the stock discharging from the spout. As 
rapidly as the stock is reduced by beating and discharged through 
the drum, fresh stock is added to the beater, thus making the 
process a continuous one. As with the Shartle attachment, it 
is assumed that the stock is beaten when the fibers have reached 
a certain fineness, approximately, and these attachments work 
most satisfactorily when this assumption is substantially correct ; 
they are best suited to very coarse papers, such as roofing felts, 
leather board, and the like, and to the re-working of broke. 

46. The Griley-Unkle Attachment.— The Griley-Unkle con- 
tinuous beating attachment is also based on the assumption 
that the object of beating is to reduce the paper stuff to a certain 
degree of fineness. In this design, the perforated plate that 
separates the stock is located in the hood, or curb, of the beater, 
above the side of the tub and on the front side of the beater roll. 
The perforations are kept clear by means of a series of plates, 
which are made to slide over the perforations (like the damper 
slides of a cook stove), and which are driven by the action of a 
small crank that is belted to the roll spindle. The turning of the 
roll throws the stock off by centrifugal force; and as it becomes 
fine enough to pass through the perforations in the plate, it is 
collected in a trough, which is built under the perforated plate 
and entirely enclosed; from thence, it is delivered to the spouting 
system below the floor, through its own down-spout. A stream 


of water is provided in the collecting spout, to thin the stock, so 
it will flow in the spouting system. The field of application 
of this attachment is similar to that of the two previously 

A particular application of this device is in the reduction of 
old papers, to prepare them for incorporation in the sheet, when 
this can be done without the direct action of the roll on the bed- 
plate. If the slapping of the roll bars is relied upon to break up 
the stock, and this can usually be done in substantially the 
same length of time as under the old method of setting the 
roll down to working position, there is an approximate saving of 
20% in power. 

47. The Roll Counterpoise. — An example of the roll counter- 
poise was shown in connection with the Marx beater. Fig. 7. 
A graduated arm A is so hung that it gives a great leverage to 
the weight supported near one end of the hghter-bar L. The 
arm A is a lever of the first class, the power arm being the hori- 
zontal distance from o' to b', and the weight arm is the horizontal 
distance from o' to a'. Lighter-bar L is a lever of the second class, 
the power arm being the horizontal distance from o" to h", and 
the weight arm is the horizontal distance from o" to a". The 
whole constitutes a compound lever having a velocity ratio of 

, , ^ , „ „ • which varies with the position of the weight W on 
a X a '■ 

the arm A ; and more or less of the weight of the roll can thus be 
counterbalanced. With the weight W kept in a particular posi- 
tion, the bearing force of the roll on the bed-plate is constant. 
The action of the roll on the stock can, of course, be varied by 
moving the weight. 

48. The Wallace -Masson Beater-roll Regulator. — With a 
given design of beater and a given type of filling in the roll and 
bed-plate, an effort is made to control the operation of the beater 
by so governing the adjustments of the roll that the roll will exert 
a given pressure on the bed-plate; the counterpoise shown in Fig. 
7, is one method of accomplishing this. Another method is the 
Wallace-Masson beater-roll regulator, shown in Fig. 18. A 
frame spans the entire tub, in a line parallel to the axis of the 
roll spindle; it carries two pivot bearings T, in which are hung 
two levers F, both of which are connected to the piston rod in the 
hydraulic cylinder C. Levers F bear, at their outer ends, on 






top of the lighter-bars H. The latter are counterpoised by means 
of levers L carrying weights W] and weights W are made suffi- 
ciently heavy to balance the entire weight of the roll, spindle, 
lighter-bars, and bearings, and the belt pull also, if it be down- 
wards. The pressure of the roll on the 
bed-plate is thus independent of the 
weight of the roll; it is developed by 
admitting water, under pressure, to cyl- 
inder C, through admission pipe A, and 
relieving through exhaust pipe E. The 
exact pressure applied to the stock is 
thus registered by the pressure gauge D. 
By making D a recording gauge, a record 
may be had showing exactly what 
pressures were used at every minute of 
the day; and it will also serve as a basis 
for framing the instructions for beating. 
Since the roll is completely counterpoised, 
the bearing is provided with an upper 
half, or top bearing, through which the 
force necessary to produce the desired 
roll pressure must be transmitted. 

49. The Adjustable Doctor.— In the 
better constructed beaters, the doctor 
. that is placed at the back side of the 
roll, over the back-fall is adjustable. 
Those in charge of mills should watch 
the rolls carefully, to observe whether 
stuff is being thrown over from the 
back to the front; if so, the doctors 
should be adjusted to prevent this as 
much as is possible. While no great 
harm results from this carrying over, it 
tends to limit the capacity of the beater 
by reducing the speed of circulation of 
the stock. When adjusting the doctor, 
it should not be set so close to the roll that ordinary bumps bring 
the doctor and roll into contact. 

In Fig. 19, is shown Shlick's beater-hood attachment, by 
which the Hollander beater maj' be so modified as to become a 
new type. The adjustable doctor D is connected with the fighter- 




bar and in some cases to the roll journal, so that the doctor is 
raised when the roll jumps or is brought up by the wheel. 

A high, deflecting hood or curb is indicated at H with cor- 
respondingly high back-fall, which, together with an elongation 
of the midfeather and heightening of the tub, increases the circu- 
lation of the stock. The increased height of the back-fall is shown 
at A and B. Many such variations are being developed and 
experimented with at the present time. 

Fig. 19. 


50. Fundamental Conditions. — It is probable that there are 
no two beater rooms in this country that have the same arrange- 
ment of beaters, chests, refining engines, mixing tanks, etc. The 
kinds of pulps used, the form and manner in which the stock 
is brought to the beater room, the method of beating, the design 
of the building and the arrangements of the other parts of the 
mill, changes in arrangement or rebuilding of old mills, power 
conditions, size of the paper machines, and many other factors, 
affect the beater-room layout. In general, however, there are 
certain fundamental conditions which are observed and which 
are considered when designing a new mill or rebuilding an old 
one. The distance between the beaters and the chests should 
be as short as possible, and the down spouting should be (as 
nearly as possible) in straight lines with no sharp turns. The 
pumps should be close to the chests, and the stuff-boxes and 


flow-boxes should be close to the pumps, refining engines, and 
chests. Long drives or shafting are to be eliminated wherever 
possible. Two beaters, or even one, to one paper machine are 
often found in small mills or in mills where the capacity of the 
paper machine is not large. When the capacity of the machine is 
very large or where a considerable amount of beating has to be 
done on each furnish of stock, the number of beaters to one 
machine may be as large as eight. In general, it may be stated, 
that good design calls for a small number of beaters for machines 
of low capacity and a relatively large number for machines of 
high capacity. 

51. Diagram of Layout. — For the purpose of illustrating the 
general relationships of the various pieces of equipment in the 






Fig. 20. 

beater room, a layout of four beaters, two chests, flow-boxes, 
a refining engine, and pumps is shown in Fig. 20. The beaters 
A are arranged in a straight line, and the dumping valves dis- 
charge into vertical down spouts JB, which lead to a collecting 


spout C that runs under the beater floor, almost horizontally. 
The spout C should have a slight pitch in both directions toward 
the point of its junction with the single down spout D, which 
leads to the chest E. In the operation of the mill, assuming 
that fresh stock is furnished to all the beaters, they would be 
furnished in rotation, and would be dumped in rotation also. 
The stock thus passes in batches to the stuff chest E, which is 
built large enough to hold at least two beaters of stock, and 
which acts as a reservoir. Leading from the bottom of chest E 
is an outlet, through which the stock is drawn in a continuous 
stream to the pump F, which raises the stock to a flow-box G, 
placed above the Jordan refining engine. The flow-box is 
provided with a regulating device and an overflow pipe L; the 
latter returns to the chest E whatever the pump F throws that is 
in excess of what the paper machine requires to pass through 
the refining engine. The refining engine H, which will be 
described later, discharges in a continuous stream into a box /, 
by means of which the pressure imposed on the stock while 
passing through the refining engine can be governed; and from 
box 7, the stock falls to the second stuff chest J. This last is 
the reservoir from which the paper machine drawls its supply, 
through another pump K, just as chest E is the reservoir from 
which the refining engine H draws its supplj-; hence, E is known 
as the Jordan chest, and J as the machine chest. In many instal- 
lations, box I is not included. Both of the chests E and J are 
provided with agitators T. 

It is customary to place the beaters in pairs, as shown in the 
illustration, with pulleys adjacent. In this arrangement, the 
drivers are least in the way, and the free space left between 
beaters may be made sufficiently wide to afford trucking way 
when desired. This arrangement permits of a group drive, 
though the beaters may be driven in pairs or individually by 
motors. The group drive tends to put a more uniform load on 
the motor, when a motor is used as a source of power. Water 
wheels, when used as sources of power, are commonly connected 
to beaters in groups; this sometimes necessitates complicated 
belting and long lines of shafting, all of which consumes power 
and involves expense for maintenance. 



52. Composition of the Furnish. — The mixture of the various 
materials that are blended in the beater, and of which the paper 
is ultimately composed, is called the furnish. The chief con- 
stituent of this furnish is, of course, the fibrous material; and 
to this may be added rosin size, mineral substances, called 
loading or filler, coloring matter and alum (aluminum sulphate) 
in varying proportions, sodium silicate, starch, etc., as required. 
The kind of paper to be made determines the presence or absence 
of one or more of these non-fibrous constituents of the furnish, 
but nearlj'- every paper requires the use of alum. The operation 
of filling up or charging the beater with these materials is called 
furnishing. The furnishing must be carried out in such a 
manner as to form a moving mass of slush throughout the process, 
which must provide for carrying the stock under the roll. It is 
a great advantage to have one kind of stock in slush or wet form, 
which can be drawn from a pipe or dug from a stock box, so that 
the circulation around the tub will begin at once. Lacking 
this, it is often necessary to make the initial slush by forcing some 
pulp under the roll with a paddle, after a small quantity of water 
has been put in; water alone will not carry dry or pressed pulp 
under the roll. 


53. Condition. — The pulp or half-stuff, the fibrous part of the 
furnish, may come to the beater room in many forms: dry 
or wet broke from the paper machine; pulped waste paper in cars 
from the drainer or in slush form from storage tanks; wood pulp 
in dry sheets, in rolls, or in dry or semi-wet laps; wet half-stuff 
in cars from the drainers; or various pulps in slush form or from 
thickeners. The handhng of the stock in furnishing is as varied 
as is the beater-room layout and the form in which pulp reaches 
the beater room. 

54. Pulping Broke. — In man}- mills, the beating equipment is 
utilized to pulp the dry waste of the mill. This is done in two 
different ways: (a) One or two beaters of the set are used exclu- 
sively as broke beaters, a small quantit}^ of broke being dropped 
into the chest each time a beater of fresh stock is dumped; or (6) 
a proportion of dry paper is incorporated with each furnish, and 




all beaters of the set are used alike. By either plan certain 
beating capacity is withdrawn from the beating of fresh stock. 
In many mills some independent form of waste-paper pulper 
is preferred, which will deliver, for the furnish, stock that has 
been thoroughly wetted and reduced to a pulp. One type of 
pulper for this purpose is shown in Fig. 21. 

55. This pulper consists of a hopper H, Fig. 21, mounted on a 
barrel B, the axis of which coincides with the axis of a shaft that 
is driven by a strong gear-reduction set. The shaft carries 
radial arms C — see detail at (a) — which turn with their ends very 
close to the inside of the barrel B. The dry paper enters the 
hopper with water and, usually, with steam also. The mixture 

Fig. 21. 

is driven toward the barrel by a worm-screw conveyor, under 
the pressure of which, it is forced through the barrel to the 
counterweighted discharge door D. During its passage through 
the barrel, it is worked by the radial arms C. These arms are 
cast with their forward face in the form of a cam, which tends to 
pinch the stock against the inside of the barrel and the pins E and 
to roll it at the same time. The result is a moist pulp, which 
readily mixes with the other stock, when furnished to the beater. 
In many cases, it is possible to withhold this disintegrated paper 
from the beater until all of the fresh stock has been beaten, thus 
saving very greatly in beater capacit}'^; it is then added with 
enough allowance of time before dumping to ensure thorough 

Another type of waste-paper pulper, also used for mixing wood 
pulp, is described in the Section on Treatment of Waste Papers. 
It is essentially a beater, with a paddle wheel on one shaft for 
circulating stock, making about 14 r.p.m. The other shaft is 
set with thin blades and makes 150 r.p.m., slushing the stock 
and mixing it. 


56. Frozen Pulp.— Frozen laps of wood pulp are a source of 
considerable trouble in the beater room. It is difficult to break 
up such laps by hand, and it is not always convenient to store 

FiQ. 22. 

them mdoors until they thaw; while to thaw them with steam is 
expensive. If they are fed direct to the beater, damage may 
result. To facilitate the furnish and to aid the beater in convert- 


ing the laps into slush of the proper consistency, the use of a 
machine is advisable. A patented shredder that is widely used 
for this purpose is illustrated in Fig. 22. The stock is fed over 
the feeding table A, and is passed on by corrugated roll B, while 
it is torn into fragments by the blades C. These blades have a 
serrated edge, and are so mounted on an arbor as just to clear 
the steel shoulder D, which is mounted on the edge of the feeding 
table. This machine is rated to consume less than 30 h.p. in the 
preparation of 5 tons of dry stock per hour. 

57. Slush Pulps. — It is common practice in news mills, and in 
some mills making higher grades, to furnish the stock in slush 
form. This is done where the preparation of pulp is under the 
same management as the paper mill and the pulp mill is conven- 
iently located, so that the pulp may be pumped directly to the 
beater or fed by gravity from storage. Stock in slush form is 
generally mechanical (i.e., groundwood), sulphite or soda pulp, 
or pulped waste papers. Where more than one slush pulp is 
furnished to a single beater, separate pumps and piping are used. 
It is customary to eliminate some of the water from these pulps 
before furnishing them to the beater by means of various types 
of thickeners, as explained in Section 7, Vol. III. 

58. Dry and Semi-dry Pulps and Half-stuff. — Practically all 
other pulps or stock are charged or furnished into the beater by 
hand. Water is first put in the beater, and then the pulp or 
half-stuff is added. Laps or sheets are broken up, and care is 
taken that large lumps of stock are not permitted to go under the 
roll. Half-stuff is dug out of drainer boxes in which it is pushed 
to the beaters. Dry broke is added slowly, and with care not to 
jump the roll. Pulp in rolls is generally added by pulHng out the 
center of the roll and pushing the end of the continuous sheet 
under the beater roll. The roll of pulp is held pointing towards 
the beater roll, which pulls the pulp in a continuous sheet from the 
center of the roll. In other cases, the roll may be run on a piece 
of pipe, held by two men, or in a frame. 


59. Usual Order. — There are many and varying ideas regard- 
ing the proper order for furnishing the different materials to the 
beater. If^stock is available in slush form, it should go in first. 
If the stockis so thin that other stock added in the form of drained, 


rag half-stuff, or dry pulp will not give the desired density, the 
excess of water is removed by the washer while the furnishing 
proceeds; then lap or roll pulp, or rags, or pulped paper is put in. 
Claj'' or other filler is usually added with the fiber or immediately 
after it. The order in which size, alum, and color are added 
varies with conditions; but, as a rule, the size is added early 
enough to allow for thorough mixing, and to have the effect of the 
size on the colors evident before the coloring has developed. 
Then the color is added and is well distributed, so that when the 
alum is finally put in, the coloring and sizing will be uniform 
throughout the mass. Exceptions to this order will be mentioned 
in the Sections treating of Coloring and Sizing. 

60. Loading. — Mineral loading, or filler, is included in the 
furnish to give the paper opacity, to give the paper a smooth 
surface or finish, to assist in the development of the color 
(principally in white papers), and in some cases, to increase the 
weight of the paper. The usual loading materials are clay, 
calcium sulphate, and talc. Clay and talc can be added to the 
beaters dry. Clay and calcium sulphate (crown filler) reach the 
mill in casks, and have to be weighed into the proper batches 
for adding to the beater furnish. Clay is also bought in bulk 
in carload lots. Talc comes in sacks already weighed. If clay is 
used, the most satisfactory way to handle it is to mix it carefully 
with water in proper proportions, have a tank of it (which acts as 
a reservoir) mechanically agitated, and draw a prescribed volume 
of this clay milk into the beater while the stock is traveling. 
Further information concerning this operation is given in the 
Section on Loading and Engine Sizing. 

61. Sizing. — The treatment of stock with a substance that 
tends to make the paper water- or ink-resisting is called sizing. 
The substance usually, almost universally, employed, where the 
sizing is done in the beater, is a soap obtained by boiling rosin 
with soda ash. This is added to the beater either by using dip- 
pers or by first emulsifying it in cold water and then adding to the 
beater in the form of milk. The latter method is finding increas- 
ing favor, largely because of its convenience, and also because of 
the better distribution throughout the beater that can be obtained 
by running in the milk while the stock is traveling. The 
chemistry of sizing is very complex, and it is not thoroughly 
understood. The important fact for the beaterman to keep in 


mind is that two things are required in sizing: first, to add the 
size, and then to add the alum. Adding the alum (aluminum 
sulphate) to the furnish before the size has had time to become 
intimately mixed in all parts of the mass, defeats the sizing action. 
The subject is more fully discussed in the Section on Loading and 
Engine Sizing. 

62. Coloring. — Adding the coloring matters is a part of the 
beaterman's duties. Here, again, the chemistry is very complex, 
and is still little understood, in some respects. Some coloring 
materials are better developed h\ following the alum than by 
preceding it in the furnish. More of the common paper-mill 
colors are better developed b}' being added before the alum, 
while with some it makes but little difference which is added first. 
However, the practical way of running a mill is to have a fixed 
rule, one that is nearest right on the average, and which will not 
involve a lot of men in the complexities of chemistry. With 
this in mind, chemists and color experts seem to agree that the 
best practice is to add the size early in the run, to add the colors 
at a time that will permit of thorough distribution and develop- 
ment, and to add the alum as near to the dumping time as is 
possible. The fact that the slight excess of alum that is always 
necessary will cause sufficient acidity to attack the steel of the 
roll and bed-plate is one more reason for this order of adding 
these materials. 

The matter of matching shades and choosing coloring materials 
involves a world of intricate technology, which will not be 
discussed here. The subject of coloring is treated in the Section 
on Coloring. 


63. Reasons for Variation. — In order that the student maj- 
obtain a general idea of some of the principles involved in the 
furnishing and beating of stock for certain tj^pes of paper, a few 
illustrations are given. It must, however, be kept in mind that 
the method of furnishing, the order of furnishing, and the manipu- 
lation of the roll, will seldom be the same in any two mills, even 
on the same type or kind of stock. Experience has indicated 
certain general methods of procedure; but in a large number of 
mills, furnishing and beating are not under close technical control, 
and the skill and experience of the beaterman is relied upon to a 


very great extent. Variation in the quality or character of the 
raw materials obtained is also a factor that makes it difficult 
to maintain the same formula for any given kind of paper. There 
are, therefore, so many factors which affect the furnish and the 
actual operation of beating, that the examples given must be 
considered to be very general. 

64. High-grade Rag Bond. — Assuming the use of a 700-pound 
Hollander beater, half -stuff from number one "shirt cuts" 
(a high-grade of new, white, cotton shirt cuttings), an 8-hour 
beating for a high-grade, all-rag bond paper, and engine sizing 
sufficient for later tub sizing, the following procedure will give 
an indication of mill practice. Before adding any stock, or 
rather before dumping the previous beater, the roll is raised off 
the plate about 15 turns of the hand- wheel. This is necessary 
to give clearance for the bunches of stock. The beater is first 
filled about half full of water, which is carefully filtered, or 
strained through a cloth bag usually made of press felt. The 
half -stuff is brought up from the drainer room in "stock boxes," 
containing about 150 to 200 pounds air-dry fiber which, as it 
comes from the drainer, contains from 70% to 75% of water. 
The half-stuff is charged into the beater by hand, tongs, or 
forks, and in this case about 4^ boxes of stock would be 
used. Water is gradually added as the half-stuff fills the 
beater. When completely charged with half-stuff and water, 
the concentration or density' of the stock will be between 4% and 
5%. The stock in the beater is very lumpy and the surface is 
not smooth. 

After about a half hour of circulation of the stock, the roll is 
lowered 5 turns. At each succeeding half hour, the roll is 
lowered 2 turns until it is 2 turns off the plate, at the expiration 
of 2| hours. The rosin size is then added, (assuming that it is in 
milk form) from a measuring tank; 70 gallons of size, containing 
about 0.3 pounds per gallon are added, equal to 3 % on the weight 
of the stock. It is preferable to strain this size while adding it. 
Strainers can be made by putting a bottom of machine wire or 
press felt on a shallow box about 2 feet square. By this time, the 
lumps of the stock have begun to disappear and the surface 
becomes more smooth. The roll is lowered by half turns each 
half hour until it is one-half turn off the plate. It is lowered a 
quarter turn at the end of the next half hour, and another quarter 
turn at the end of the next hour. The color, dissolved in hot or 


cold water as the case may be, and strained, is added. At the 
end of 6| hours, the hand wheel is turned down another quarter 
turn, leaving the full weight of the roll on the stock. About 
25 pounds of alum, dissolved in hot water and strained, is then 
added, and at the end of the 8-hour period, the roll is raised 
15 turns, the valve opened and the stock is dumped to the Jordan 
chest, with some additional water to slush it down. This 
manipulation is modified to a considerable extent by different 

65. Mixed-stock Furnish. — Some furnishes may require the 
use of two or more kinds of stock that require different beating 
treatment, such as rag stock and bleached sulphite in a 50% rag 
bond. It often happens that the two stocks are beaten 
separately, and mixed in proper proportions in the Jordan chest. 
Care has to be exercised that there is proper mixing; and it is 
generally necessar}^ to have a special mixing chest, similar to that 
shown in Fig. 10. It is obvious that some such arrangement will 
produce better paper, for the severe beating treatment to which 
the rag half-stuff must be subjected may be detrimental to the 
sulphite. A similar manipulation is advantageous where rope 
stock and sulphate pulp are used in strong bag papers, or where 
rags and soda pulp are used in blotting papers. In some cases, 
it is common practice, where the proportion of long fiber (requir- 
ing severe beating) is considerably greater than the short stock, 
to charge the former into the beater by itself, and it is partially 
beaten before the addition of the short fiber. This method is 
preferable to putting both stocks in at once, but it does not have 
some of the advantages of the separate beating, as described 

66. Book Paper. — The furnishes for book papers will vary 
widely. Relatively cheap raw material must be used, and 
production is an essential factor. A rather high grade of book 
paper would consist of equal amounts of sulphite and soda pulps; 
these would be furnished to the beater by hand, and would receive 
a short beating of about 2 hours. For a 2000-pound beater, 
about 10 bundles of 55% air-dry sulphite pulp or about 1000 
pounds of dry sulphite would first be added, and the beater then 
filled up with soda pulp. Some 500 pounds of clay would 
immediately be added, either dry or in suspension in water from 
tanks. This would give about 15% of loading in the finished 


paper. About 45 gallons of size would be added next from a tank, 
equal to 2 % of the weight of the stock. Color would be added 
shortly afterwards, the roll lowered, and the alum added shortly 
before dumping. After 2 or 3 hours, the stuff is dropped to the 
Jordan chest. 

Such a procedure or furnish is modified to a great extent where 
pulped magazine stock is used or where the pulps are available 
in the shish form. In some cases, the sulphite pulp is beaten 
separately, and the pulped magazine stock or slush pulps are 
added in a suitable mixing tank or chest. Most book papers 
contain clay, or some similar loading material, and also small 
amounts of rosin sizing. It should be remembered that print- 
ing inks are made with oils, not water; hence, printing papers 
need not be water resistant. In some cases, bleached mechanical 
pulp is used in the furnish, particularly where the paper is to 
be used for current magazines of little permanent value; such 
pulp is usually added in slush form. 

67. Newsprint. — In general, newsprint is made of about 70% 
to 80% of mechanical pulp, the remainder being sulphite pulp, 
both unbleached. Due to the necessit}'- for low prices, costs must 
be kept to a minimum, and production is of paramount impor- 
tance. This tj'pe of paper is therefore generally made in a mill 
having a convenient supply of pulp; and it is probable that a 
majority of news mills use the pulps in the slush form, and have 
little, if any, use for a beater, except as a mixing vat. Very 
small quantities of rosin sizing and alum are frequently added 
and, in case of "white" news, some blue dyes. Any further 
conditioning of the fibers is done almost entirely by one or more 
refining engines. 

68. Coarse Boards. — Probabh^ the larger proportion of the 
tonnage of coarse boards produced have "mixed papers" as their 
chief constituent. In the production of such boards as chip, 
binder's, cloth, trunk, etc., the waste paper is disintegrated in a 
beater or by special pulping equipment, and is fed direct to a 
refining engine. Where combination boards are being made, the 
stocks for the different vats is beaten separately and dropped 
to separate chests. 




69. Definitions. — Certain terms are used by paper makers in 
connection with the treatment that the fibers receive in the beat- 
ing process. Such words as shortening, crushing, brooming and 
similar terms are freely employed in the language of the mill as 
though they were accurately descriptive of certain phases of 
beater action. Unfortunately, however, in spite of the fact that 
experienced mill men are able to produce at will close and dis- 
tinctive results in the beater, accurate knowledge regarding 
precisely what happens is limited ; consequently, an exact wording 
of the meaning of the terms applying to these results is very 
difficult. General definitions of some of these terms will now be 

Half -stuff is the fibrous material (pulp) in condition to go into 
the beater. When this material has been beaten, it is called 
whole-stuff or, simply stuff. When the whole-stuff has been 
diluted and is read}^ for the paper machine, it is called stock. 
Sometimes the words stock and stuff are used interchangeably, 
but a distinction should be made between them, to accord with 
these definitions. Note that in addition to the fibrous material, 
stuff may include other materials, as sizing, color, loading (filler), 

By consistency is meant the per cent of air-dry paper material 

in the stock (or stuff); also called density or concentration. It 

is found by dividing the weight of air-dry fiber in any particular 

amount of stock (stuff) by the total weight of the stock (stuff). 

Thus, representing the total weight of the stock (stuff) by W, the 

weight of the bone-dry material contained in it by w, and the 

, ^ ^ iy-J-0.9 lOOOty , , • , 

consistency by C, C = — ^ — X 100 = ^qw"> because the weight 

of bone-dry pulp is 90%, or 0.9, of the weight of air-dry pulp or 
stock (stuff). 

Free stock is a mixture in which the fiber has been prepared in 
such a way that when delivered on a sieve it forms a mat through 
which the water readily drains; this is an essential characteristic 
of stock for fast-running paper machines, as for newsprint and for 
papers that are to be bulky or absorbent. Slow stock has been 


so prepared that, under the same conditions, the water drains 
from it slowly; it is also called greasy or slimy, because of the feel 
of the stock after very long beating. Such stock requires a slow- 
running machine and increased suction; it is suitable for bonds, 
writings and parchments. The terms short stock and long stock 
are relative. The fibers are shortened by being cut in the process 
of beating or refining, or both. A cotton fiber, perhaps ^ inch 
long originally, may be shortened considerably and still be longer 
than a full-length wood fiber that is, say, j inch long. Short 
fibers that are mixed with long ones tend to form a more closely 
felted sheet than long fibers alone. Crushed fibers are produced 
by such action of beater or refiner as may be thought of as pounding. 
Fibers, and bundles of fibers are sometimes split lengthwise into 
what are called fibrilloe. When this splitting affects only the 
ends, the fibers are said to be broomed. Hydration means the 
taking on of water by the cellulose fiber; it is induced by the 
mechanical action of the beating apparatus and the rubbing 
together of the fibers. Hydration results in a gelatinous film on 
the fiber, which assists in cementing the fibers in the sheet. 


70. Mechanical Action. — Before discussing the theory of 
beating, it would be well to consider the facts as to what results 
are obtained by beating. These results may be grouped into two 
classes, — mechanical and chemical, — which, when combined to a 
greater or less extent, produce the condition of the stock desired 
for proper felting of the fibers on the paper machine. The 
change in the physical structure of the fibers may best be illus- 
trated by photomicrographs. It is to be noted that the cotton 
fibers in Fig. 23, are quite long and unbroken; whereas, in Fig. 24, 
the fibers are cut, bruised, frayed, broomed and split, and retain 
little of their former unbroken character. In this case, the stock 
was subjected to prolonged beating, to "draw-out" the fibers 
with a minimum of cutting action. In the case of a rag blotting 
paper, the tackle would be sharp, the consistencj- high, and the 
cutting action greater than the bruising. In Fig. 25 are shown 
some unbeaten sulphite fibers,^ while Fig. 26 indicates the damage 
done to them by the mechanical action of the fly bars and bed 

* Characteristic fibers produced by the several processes from wood 
are shown in Section 1, Vol. III. 




plate. In the case of mechanical pulp, the beating results 
principall}^ in a separation of fiber bundles. Beadle ' has shown, 
by the measurements of samples of stock taken from the beater 
at frequent intervals during the beating process, that the fibers 
are reduced in length, and that this reduction takes place largely 

Fig. 23. 

Fig. 24. 

Fig. 25. 

Fig. 26. 

during the early part of the beating. It is, therefore, the general 

rule that, wherever there is any considerable beating, the physical 

structure of the fiber is changed by mechanical means. The 

fibers to be used for paper making are thus shortened, fraj'ed, 

split, etc., either in the beater or in the refining engine, to permit 

of better felting or interlacing of the fibers on the paper-machine 

' Chapters on Paper making, Vol. V, by Clayton Beadle, page 151, 
Fig. 29. 


wire. The shake of the wh-e tends to form a compact and 
uniform fabric, which produces a better appearance and a more 
even surface for printing. 

71. Chemical Action. — It is more difficult to describe or 
illustrate the chemical change produced in the fibers by beating. 
The simplest statement is that the cellulose fiber combines with 
water under certain conditions. This action is accelerated by 
agitation, bj^ friction, or by treatment with certain chemicals. 
If carried to its extreme, this action results in a slimy, gelatinous 
mass, wherein all semblance of fiber structure has been lost; 
actual beating does not go this far, but some of this slimy sub- 
stance is contained in nearly all high-grade papers. Glassine 
contains a high percentage of such hydrated cellulose, while 
blotting paper, in which it would detract from the absorptive 
capacit}^, has a verj^ small percentage. Stuff that has been 
beaten a long time is generally slow or wet. The effect of this 
at the paper machine is to require more suction on the machine 
suction boxes, and to produce a more compact, dense sheet, 
hard to dry, and likely to cockle in drying. The hydrated 
cellulose acts somewhat as a binding material, and it tends to 
increase the tensile and bursting strengths of the paper by serving 
as a cement or binder; it produces a hard, rattly, snappy sheet. 
When a soft, limp, absorbent sheet is wanted, the beating is done 
drastically and quickly, cutting the fibers rapidly, and allowing 
as little time as possible for the development of the slime or 
hydrated cellulose. 

72. How the Results Are Obtained. — Bearing in mind the 
various results obtained by beating, as they have just been 
described in general terms, it is necessary next to consider the 
ways by which such results are reached; and this may be done: 
first, with reference to the practical operation of beaters in paper 
mills; and, second, with reference to the theories of beating that 
have been evolved to explain the facts, as well as to assist in 
making improvements on present designs of beaters. 

Take, for example, the case where all of the pulps that are to 
compose the final paper are beaten together at one time, for this 
is the simplest case. After the beater has been furnished and the 
roll action started, there is nothing added or taken away; no 
change can be made in the speed of the roll; no change can be 
made in the form, hardness, or number, of bars in roll or bed- 
plate; the only manner in which the beaterman can influence the 


quality of the final paper is by his manipulation of the roll up or 
down, including not only his positioning of the roll, but also 
the length of time of treatment at any given roll adjustment. 
Upon this one factor, usually entrusted entirely to the skill of 
the beaterman, rests the outcome; that is, whether the final 
paper will or will not be of the required character, and whether 
the paper machine can or cannot run economically. The beater- 
man judges the progress of the beating by feeling the stuff with 
his hand, or by dipping out a small sample in a pan of about two 
quarts capacit}^ shaking the stock together with additional water, 
and observing the tendencies of the fibers to clot, or gather. 

73. With the composition and the density of the furnish once 
fixed, low setting of the roll, giving violent, drastic, punishment 
to the stock, will result in the greater physical damage to the 
fibers. If this be maintained for a comparatively short period, 
and the beater then dumped, the resulting stock will be free, 
comparatively well formed in the paper, and the final paper will 
be soft, inclined to be fuzzy, weak in tensile and bursting 
strength, easj^ to tear, possessing low wearing endurance, and, 
unless especially sized, absorbent. Under the same conditions 
in the beater, if the roll be set lightly, and that setting be main- 
tained for a comparatively long period, the resulting stuff will 
be slow, and, when run out into paper, will still be well formed, 
but more cloudy, and the final paper will be hard, firm in surface, 
strong, with high wearing endurance, and in much less need of 
sizing to make it resist water. A paper produced in the first 
way will not take a high finish in calendering, whereas a paper 
produced in the second way will readily take high-calender 
finish. Either action of the roll maintained for a long enough 
period would result in slow stuff; but the two actions would 
not result in the same quaHty of paper, except when carried out 
almost indefinitely; in which case, the fiber would entirely 
disappear and a gelatinous mass would remain. 

By far the most usual procedure, for the higher grades of 
paper, once the composition and density of the furnish have been 
fixed, is to begin the beating with a moderate setting of the roll 
and then gradually to lower the roll at intervals during the run. 
Where the beating is done in this way, the beaterman must 
decide how hard to set his roll at each change in setting, when to 
change the setting, and when the desired final result has been 
attained; great responsibility therefore rests upon the beater- 


man. The task is the more dehcate because of the fact, revealed 
by experience, that results are retarded and sometimes destroyed 
by raising the roll (setting it less severely) during the run. The 
roll must never be brought upward, but always progressively 
downward, except at the end of a run, especially if no Jordan 
is used, when the roll may be raised a hair's breadth, while the 
fiber is brushed out. 

74. These rules in beating have been developed through 
5'ears of operation with rag stock, and with other long-fibered 
stocks, for the higher grades of paper. Since the general intro- 
duction of wood fibers for the bulk of commercial papers of all 
kinds, refinement of practice in beating has tended to yield to 
rapidity, and the tonnage required of him leaves the beaterman 
little chance to attend to progressive roll settings. Most mills 
using wood pulps do their beating with a single setting of the roll. 

The beaterman judges the setting of his roll by two means: 
first, bj^ the number of turns of the adjusting hand wheel; and, 
second, more finel}^ by the sound that he gets by putting one 
end of a stick on the bed-plate chair and his ear to the other end. 
This same device tells him how well his roll fits the plate, and 
how accurately round the roll is ground. 

75. Fibrage Theory. — Five years' experimenting by the 

Danish engineer. Dr. Sigurd Smith, ^ have led him to w^hat he 

terms the fibrage theory of beating. As he points out, if a steel 

rod of square cross section is moved through a tub of stock, with 

its sharp edge forward, a certain amount of fiber will collect 

on that edge ; and the character of the fiber and the density of the 

mixture in the tub determine how much fiber will thus collect. 

Similarly, as the beater roll turns, the bars advancing toward the 

bed-plate carry with them a certain amount of fiber collected 

on the edge. The roll bars then advancing across the bars of the 

bed-plate act on these fibers in a manner similar to the action 

of a lawn-mower on blades of grass ; that is, it cuts some of them 

directly, but damages a great many more by fiber acting upon 

fiber within the mass that is imprisoned between the bars. 

Thus, if the consistency be thin, less fibrage will be collected on 

1 The Action of the Beater in Paper Making, by Dr. Sigurd Smith, Journal 
of the Roval Society of Arts, Vol. LXXI, No. 3655, Dec. 8, 1922. Paper 
Trade Journal, \o\. 75, No. 26: Vol 76, No. 1, Dec. 28, 1922 and Jan. 4, 
192:3. The Paper Makers' Monthly Journal, Vol. 60. No. 12, Dec. 15, 1922. 
Also in book form from Pulp and Paper Magazine of Canada, or Technical 
Association of the Pulp and Paper Industry. 


the edges of the bars; and a given distance between roll and bed- 
plate will result in less fiber damage than if the consistency be 
thick and the distance between roll and plate be the same. This 
conclusion has been borne out by actual beating in the mill. 
Acting on this theory, Dr. Smith has designed a type of beating 
tackle to impose on the stock greater action without a proportional 
increase in the power required. He explains that to make the 
bed-plate wider would not increase the effective beating that 
could be done under given conditions in a given time, a fact that 
has been shown in mill practice many times, as he says; and he 
offers as the reason, that in going across a single plate no new 
fibrage can be collected on the edge of the beater bar, and a 
comparatively narrow plate suffices to treat as much fibrage as 
is collected at one time. By arranging two plates, however, with 
a properly designed space between them, new fibrage can be 
collected on the beater bars as they pass from the first plate to 
the second; thus the second plate can be made effective also. 

76. The Circulation Theory. — Granted that effective beating 
depends mainly on frequent passing between roll and bed-plate 
by the stock, there are then two ways in which this may be 
accomplished: First, to increase the number of plates under the 
roll, or, what in principle is the same, to increase the number of 
sets of rolls and bed-plates in one tub; second, with one roll and 
bed-plate, to increase the speed of circulation. By travehng 
more rapidly around the tub, the stock is brought more frequently 
under the roll; conversely, a beater that will propel a given 
concentration of stock at a higher rate of speed will propel stock 
of a higher concentration at the same speed. Stock of the higher 
concentration, as has been pointed out, will receive more damage 
to the fibers in one passage under the roll than stock of the lower 
concentration, the setting of the roll being the same. Thus, there 
is a double advantage in the beater that is so designed that, with 
slight increase of power, it can propel the stock at a higher speed ; 
the effective beating may be increased either by reason of higher 
speed of circulation, or by reason of higher concentration. In 
practice, the newer designs that have been offered accomplish 
much in both directions. 

77. Most Efficient Degree of Concentration. — An ingenious 
method has been evolved for finding the consistency of stock that 
will enable a given beater to perform most efficiently; that is, do 




a given amount of work on the stock with the least expenditure 
of power per ton of paper produced. Based on the assumption 
that 50 times under the roll completes the beating, a series of 
tests were made on a given furnish at different consistencies, 
wherein the consistency, the speed of travel (circulation), and 
the power input to the motor, were measured; and these tests 
led to the following table: 




No. of 

No. of 

No. of 

No. of 











in feet 

to turn 
50 times 

per 24 

stock per 






24 hours 

per ton 






































































These figures plotted in 
the form of a chart are 
shown in Fig. 27. The chart 
brings to view more forci- 
bly the fact that with this 
beater, and the particular 
stock with which it was fur- 
nished, the greatest produc- 
tion per day occurred when 
the consistency was 3%, and 
at that same consistency, the 
power consumed per ton of 
stock was least. If the con- 
sistency could be increased 
without reducing the speed 
of travel, and without in- 
creasing the power con- 
sumed proportionately, then 

Pounds per Charge 

,.„0 JOO 600 900 IMO 1500 1800 2100 2400 

ijo V 

4 ^ 

120 ^_ 


"° At- 4^ 

i_^ 1 

100 100 100 \_ 1 1 ~t^ " 

A "^ 

90 90 90 

o - ^V 

80 20 80 80 S) \ 

" V v-ii 

TO cio| 70 T V j;: 

i > ^ ^z^^ ^" 

^-gjs^^fe^m vA \ _i_i 

^ % ^ 4li > XI 

sat ^^ 50 .^ ^ r +t^ 

1 1- t ^ A \ xr~ 

wJlOlAO 40 S V . \ r 

^vlS V 7 ^ 

30 30 30 ^tV \ I 

^^^ ^ -J 

20 S 20 20 S^ ^ T" j 

'^5:Jx d 

10 10 10 \^^ -t 

® ® ® (L %^_~ ^--^^^^ ^ 

P... ..,. ,^ '^ZL ^^i.J 

U 2^45679 

Per Ceirl' Consisl-ency 

Fio. 27. 


the efficiency of this beater would be increased; or if the speed 
of travel could be increased without reducing the consistency, 
and without increasing the power consumed proportionately, then 
the efficiency of this beater would be increased. To do either 
would require changes in the design of the beater. 

78. The Viscosity Theory. — Experiments leading to the two 
foregoing theories have rested on the observed behavior of the 
stock in going over the paper machine, and on the quality of the 
final paper. The subject has been treated in this country from 
a radically different angle. Thus, the first step of the series of 
tests was to develop means by which small pulp sheets could be 
formed under exactly standard conditions; so that they could be 
tested in all of the known ways separately, and conclusions could 
be drawn, independently of the manner in which the beaten stock 
might be treated in the refiner or on the paper machine. More- 
over, such sheets were made from samples of the stock taken 
from the beater at regular intervals during the beating; and, in 
this way, charts were constructed showing the changes made in 
bursting strength, folding strength, sizing, shrinkage, and bulk, 
separately, as related to the setting of the roll, the pressure exerted 
by the roll on the bed-plate, the speed of circulation, consistency, 
and power consumed. It was found, for example, that a given 
amount of beating, applied to a given stock at a given consistency, 
often increases bursting strength, but decreases folding strength, 
as compared with a less amount of beating; and the question 
arises, which manner of beating should be considered more effec- 
tive. In other words, it is in many cases misleading to assert 
that a certain roll action, or a certain number of passages under 
the roll, constitute a given amount of beating; for such an assump- 
tion does not take into consideration all the facts. The amount 
of beating must be judged primarily by the particular qualities 
in the final paper that it is desired to have; then that manner of 
beating best adapted to enhance those qualities is the one to be 

The tests were carried out in the way described for seven years 
under a great variety of conditions, for the purpose of finding 
some method of so directing the beating of stock as to be able to 
repeat in a succeeding furnish of stock the same qualities, at the 
end of the beating, that had been produced in a previous furnish 
of stock. The key to the problem was finally found when it was 
discovered that changes in frictional resistance in the stock 


have a direct bearing on the quaHties of the final paper. With a 
given furnish and a given consistency, the action of the beater 
results in changes in the surface friction, and internal friction, of 
the stock. If these changes are made in the same way and to the 
same degree in one furnish after another, the final paper will 
possess the same qualities. 


79. Two Ways of Controlling. — There are two ways of attack- 
ing the problem of control of beating: one way is to control the 
setting of the roll directly; the other way is to control the setting 
of the roll through measurement of the results of roll action on the 
stock. Bj'- the first method, the control of the roll directly, 
either the distance between the roll and the bed-plate, or else the 
weight exerted by the roll on the bed-plate, can be the factor 
chosen for control. But it must be clear at the outset, and 
always kept in mind, that if a beaterman is to be required to set 
the roll at the same distance above the bed-plate every time, or 
if he is to be required to set it upon the bed-plate with a given 
pressure each time, he must have some method of getting the 
beater furnished to the same depth and with stock of the same 
densitj''; otherwise, these mechanical elements of control cannot 
be expected to give uniform results. 

When no special instructions or apparatus are given to the 
beaterman, the condition of the stock and the manipulation of 
the roll are determined by him by the feel of the stock, or by the 
use of a small bowl or copper dipper, of about 2-quart capacity. 
Into this bowl, a small portion of stock is mixed with a relatively 
large quantity of water, and the appearance of the fibers and the 
absence of small clots or bunches of fibers are an assistance in 
judging the condition of the stock in the beater. Often two 
vessels are used, and the stock is observed as it passes over 
the edge of one to the other. Also refer to description of blue 
glass test in Section 3, Vol. III. 

80. Control of Density. — A prime requirement of control of 
beating, then, is control of density (consistency) of the furnish, 
that is, of the percentage of paper-making material in the stock 
In one or two mills where this problem has received careful 
attention, methods have been worked out for weighing the pulp 
into the beater and measuring in the water. But pulp comes to 




the mill in many forms and at different moisture contents; and to 
be weighed correctly, it must be reduced to the same moisture 
basis. A very effective device for doing this is a small centri- 
fuge, such as is used by laundries for a preliminarj'- drying of 
clothing. It has been found by experiment that a sample of wet 
stock, properly treated in a centrifuge, will always come out at a 
uniform moisture content. In order to compute the weight at any 
moisture content, it is only necessary to know what per cent of 
moisture exists; therefore, the sample that is treated in the centri- 
fuge gives the basis for all calculations regarding moisture; it 
gives the beater-room management data for computing exactl}'^ 
what quantities of the various stocks are to be weighed in, to 
fill a given furnish, and what quantities of water to add. Until 
this method was devised, the problem of furnishing definite 
amounts of stock from the drainer, for example, has been almost 
beyond precise control. 

81. A Consistency Regulator. — A successful type of consistency 
regulator widely used on wood pulps is shown in Fig. 28. Stuff 

Fig. 28. 

enters the constant-head box N, in the bottom of which is a round 
orifice M in a brass plate. A constant head is maintained by 
admitting m.ore stuff through pipe L (pumped at a constant rate 
from the pulp tank or Jordan chest) than can pass through the 
orifice M, the excess overflowing the baffle into pipe /, which 
conducts it back to the chest. That part of the stuff that flows 
through orifice M passes through pipe into the variable level or 
weighing chamber H, which is mounted on a scale beam J that 
balances on knife-edge bearings at P. The counterweight K 


may be moved along the other arm of the beam as in any weigh- 
ing machine, and is used to balance H and its contents. 

82. Now it is well-known that the friction of stuff flowing in 
pipes varies with changes in consistency; also, if a relatively 
constant volume of stuff is to pass through a pipe of given size, 
it will require a greater head (or pressure) to maintain the same 
flow when the consistency of the stuff is increased. This fact is 
made use of in the following manner: 

Through a small bj'pass, taken off from the main stuff pipe, 
as close as convenient to the stuff pump, sufficient stuff is con- 
tinuously drawn to maintain an overflow in the head box A^ of the 
regulator, thus maintaining a constant head on the orifice M, and 
producing a constant flow in the pipe 0. Since this orifice offers 
a minimum of frictional resistance to the passage of the stuff, the 
amount discharged through it to the variable-level chamber H 
beneath it, will vary but little with changes in consistency. In 
passing from the variable-level chamber H, however, the stuff 
meets with considerable frictional resistance, which is gov- 
erned by the reducing elbow R and by the size and length of the 
goose-neck outlet pipe S, w'ith the result that the level in H rises 
a sufficient amount to overcome the resistance of the reducing 
elbow R and pipe S, and maintains the flow. Thus, when the 
consistency of the stuff increases, the level in chamber H rises; 
and when the consistency decreases, the level in chamber H falls. 

A water-supply pipe A is connected to the inlet of the stuff 
pump (which supplies stuff to be regulated) by means of a gate 
valve, the stem of which is connected to a screw B passing 
through a double-faced ratchet wheel C. A pawl D is provided 
for rotating the ratchet wheel in either direction; a set of links E 
connects the scale beam / of the regulator and the pawl; a shaft 
F connects with an eccentric for operating the pawl ; and a safety 
stop disengages the pawl when the valve is wide open or shut. 

83. Stock of a given kind at a given consistency will fill weighing 
chamber 77 to a definite height; that is, where enough head is 
created above goose-neck pipe S to cause a rate of flow equal to 
the flow through orifice M. Thus, a definite weight of stock 
plus metal is estabhshed for any desired consistency of stock; 
and this weight corresponds to such setting of counterweight K 
as will balance it. The counterweight K is set to balance the 
weight of the chamber // and its contents at the desired consis- 


tency, and when K and H are iu balance, pawl D will not engage 
with either side of the ratchet. If the consistency of the stuff 
increases, the additional frictional resistance will cause the stuff 
to back up in chamber H, increasing the weight of the stuff in 
the chamber (since the level of the stuff in the chamber rises); 
this brings down that end of the scale beam to which chamber H 
is attached, and causes the other end, with the counterweight, to 
rise; this movement is transmitted by the links E, which cause 
the pawl D to engage with the ratchet wheel C, and rotates the 
ratchet wheel. Since the ratchet wheel cannot move sideways, 
it Avill cause the screw B (to which it is threaded) to back out and 
open the water-inlet valve until sufficient water is added at the 
pump to reduce the total volume of stuff passing through the 
pump to the proper consistency. When this occurs, the scale 
beam again becomes horizontal, the pawl comes to neutral posi- 
tion, engaging neither side of the ratchet, and the water valve 
remains open the necessary amount. If, now, the stuff becomes 
too thin and less water is required, an opposite movement (due 
to the same causes as just described) will close the valve the 
necessary amount. A safety stop disengages the pawl when the 
limits of the valve travel are reached. 

If sufficient care be taken to insure proper operating conditions, 
stuff can be controlled with this apparatus with a maximum 
relative variation of 5% over or under the desired consistency. 
The same apparatus may be attached to the pump and pipe 
system delivering any kind of stuff fj'om the Jordan chest, 
through the constant-head regulating box to the Jordan, or from 
the machine chest to the paper machine. 

84. Instead of separate constant-flow regulating boxes deliver- 
ing stuff of uniform density to the mixing tank, there may be used 
an automatic proportioning device recently developed. This 
consists essentially of the required number of constant-level stuff 
chambers, from which stuff is delivered through flat openings, 
which are provided with a slide valve that opens one part as it 
closes the other. With the proper proportions of pulp in constant 
quantity at uniform consistency thus insured, it is possible to add 
color, size, clay, etc., in solution or suspension in just the right 

85. Consistency Indicator. — The beater drag, Fig. 29, gives 
control of the consistency of the furnish; accomphshed by bring- 




ing the arrow L to a prescribed point and, at the same time, hav- 
ing the beater filled to exactly the same depth. This result is 
effected most readily if one kind of stock is coming to the beaters 
in slush form; for, in that case, a steady stream of slush stock may 
be run in while water is taken out b}'' means of a cylinder washer, 
thus maintaining the proper depth in the tub, until the arrow 

Fig. 29. 

stands at the right point on the scale. This method is suffi- 
ciently accurate in careful hands to control the consistency of the 
furnish within a relative variation of 2%. 

86. Controlling Consistency at the Jordan. — In mills wheie no 
method has been adopted for the control of the densitj'' factor, it 
is customary to compensate for the fluctuation by adding water 
at the Jordan, adding more when the stock seems thick and less 
when it seems thin. However, since density is the starting point 
in the control of beating, the better plan is to maintain uniform 


consistenc}', when once obtained, from the beaters to the paper 
machine; this may be done by adding the proper amount of water 
in dumping, so that the consistency of the stock in the chest is 
kept uniform. A very satisfactory device for this purpose is the 
recording liquid-level gauge, since paper pulps are of prac- 
tically the same weight as water. The diaphragm of the record- 
ing liquid-level gauge is placed well down in the chest; when it 
shows that the surface of the stuff in the chest has fallen to a 
certain level, the next beater is dumped, and the proper amount of 
water is used in dumping to bring the surface of the stuff up to 
a higher prescribed level. If, then, this predetermined amount of 
dumping water is made such that the resulting consistency in the 
Jordan chest is right for passing through the Jordan, no water has 
to be added at the Jordan, and the uniformitj^ of consistency once 
established in the beater is maintained up to the paper machine. 
It has been found that this factor can be so well controlled that 
ream weights on the machine almost maintain themselves. 

87. Control by Setting of Roll. — Returning now to the plan of 
controlling by changing the setting of the beater roll, the same 
results in the stock will not be produced by the same position of 
the roll or the same roll pressure, as has already been shown, 
unless the consistency is the same. But even with the consis- 
tency uniform, the quahty of the stock coming to the beater varies. 
Some stocks require drastic roll action and some less drastic 
action, for uniform results in the paper. That which requires 
less treatment will get over-treated, by being subjected to the 
same roll setting, as compared with that which requires more 
treatment, and the independent means of governing the roll 
setting would thus fail to compensate. This method has been 
the subject of many careful experiments, in which both of the 
mechanical methods of governing the roll setting were employed. 
To obtain control of beating, therefore, it is necessary to develop 
some measuring unit to express the result of beater treatment on 
the stock. 

88. Watt Meter Control. — It has been stated that a large 
pa,rt of the power used in beating is consumed in circulating the 
stock; with any one beater, this power consumption will be 
constant for the same furnish and consistency. Any variation 
in the power consumed will then be caused by a change in the 
adjustment of the roll and its consequent pressure on the bed- 


plate and effect on the stuff. Any changes in power consumption 
are immediately reflected in the reading of a watt meter in 
circuit when only one beater is driven from a single electric 
motor. By using a reliable recording watt meter, a curve is 
drawn that serves as a control and guide; and by dupHcating 
the curve, it is possible to duplicate beating conditions very 
closely, although for really accurate work, this method is probably 
not so dependable as some others, because of the elements of 
beating action which it leaves out of account, 

89. The Beater Drag. — The theory of beating control will be 
discussed later; but it may here be stated that the roll counter- 
poise and the Wallace-Masson beater-roll regulator both operate 
to govern mechanically the setting of the roll, whereas the 
beater drag, shown in Fig. 29, measures the changes produced 
in the stock by beating. 

Referring to Fig. 29, a square shaft S spans the channel of 
the beater opposite that in which the roll runs; it is supported 
on guides at its ends, which are arranged to lift and fall on stan- 
chions, through a distance sufficient to permit the drag to be 
lifted up out of the tub during the dumping and furnishing 
operations. Fastened to the shaft S and held rigid by it is a 
frame W, which, in turn, carries a bearing B, by means of which 
an oval rod R, free to swing slightly, is hung vertically. In 
Fig. 29, the stock is supposed to be traveling from left to right. 
Rod R is anchored back to frame W through a coiled spring, 
enclosed in spring case C There is a pivot bearing at P, which 
carries a light-weight bell-crank lever L, on the outer end of 
which is an arrowhead, which runs up and down across scale U. 
The inner end is connected by link V to the oval-rod bearing 
bracket Y. At the lower end of rod R, is a smooth body or bulb 
H of proper shape, perhaps lemon-shaped. As the stock thick- 
ens and creates a greater pull against this bulb, the rod R swings, 
which motion is conveyed through F to L; this causes L to 
rotate about P, and thus deflects the arrowhead upward; but 
when the stock is made thinner, the pull diminishes, and the 
arrowhead falls. Each position of the arrowhead is recorded 
automatically by suitable clock-work mechanism. 

As the beating progresses, a curve is automatically drawn 
on a chart, which represents the varying degree of pull exerted 
by the stock against the bulb H. If the stock is furnished to 
a fixed depth in the tub at the beginning of the run, and the 




arrowhead is brought to a predetermined point on the scale, the 
density of the furnish is thereby made uniform. The combi- 
nation of a fixed furnishing point and a given curve on the 
record, composes the basis for instructions as to the beating; 
and the record of the recorder provides the history of every 
run, which may be compared with the instructions issued. 

90. Experiments extending over five years, made both in the 
laboratory and under actual mill conditions, resulted in establish- 

FiG. 30. 

ing the following principle: The mass of stock in the beater is 
treated as a fluid mass, such as molasses; and the friction of 
this fluid mass on bodies that are made to move through it is 
measured, coupled with the friction of this mass when rubbing 
on itself. In other words, both the internal and surface frictions 
of the mass are measured. As the beating progresses, these 
frictional factors change. A typical curve, as drawn by the 
automatic recording attachment, is shown in Fig. 30. The 
principle is, then, that if this curve is reproduced each time that 
the same furnish is made in the same beater, the quality of the 
resulting paper will be uniform. 

91. In Fig. 30, each horizontal line represents 10 points on 
the scale of the beater drag. The consistency of the furnish was 
determined by thickening with cylinder washer (Art. 42) to point 
A. Thickening was continued until room was made in the tub for 
the size and clay, both in milk form, and they were added at 
point B, bringing the pointer down to C, where the first reading 


was taken. It is interesting to note at point E, where the alum 
was added, that this had a marked effect on the reading, raising 
it about 30 points. To repeat this curve with the same furnish, 
instructions are given in the form of a table of readings, one 
reading for each period of time, say 15 or 20 minutes, throughout 
the run; the beaterman adjusts his roll as the riin proceeds, in 
such a way as to follow out the readings as set, and thus duplicate 
the curve. Each different beater of the set on the same furnish 
requires a different curve, because beaters do not have the same 
action on the stock, even when in the same condition of repair or 

Although this principle has not been applied in daily practice 
to other than short-fibered stocks, a sufficient number of experi- 
ments have been made to indicate that it has universal applica- 
tion. Long-fibered stocks require, however, a different form of 
measuring device — one that will avoid snagging. But the rela- 
tionship between the frictional resistances and the quality of the 
stock is apparently a universal principle, in connection with the 
beating of stock for paper. 

92. Control by Measurement of Freeness. — The freeness of 
stock prepared for making paper decreases with the increased 
degree of hydration of the fiber. The progress of this action may 
be followed and measured relatively by determining the rate at 
which water will drain from the stock at standard temperature 
and consistenc3^ The effect of temperature is not always fully 
appreciated; it is, however, very important, since water at its 
boiling point drains about five times as fast as water at the 
freezing point. It is also obvious that results can be compared 
only when referred to stock of the same consistency. Fig. 31 
shows an apparatus used in a number of mills for measuring 
the freeness of the stock; it is operated as follows: A cer- 
tain quantity, say a quart, of stock from the beater is poured 
into a sieve having a fine-wire screen bottom. This is placed over a 
coarsely perforated or grooved plate, a piece of felt is laid over 
the stock, and is pressed down with a weight for a definite time. 
A prehminary test will show about how much bone-dry fiber 
is in the pressed cake. On the assumption that this is nearly 
constant for the class of fiber used, enough pressed fiber is taken 
to make about 1000 c.c. of a suspension containing 1 per cent of 
fiber. Another portion of the cake is weighed and tested for 
moisture content. (A correction factor can be applied to the 




test result, if necessary.) Thus, if the cake contained 50% 
moisture, 20 grams would be required to furnish the 10 grams to 
be mixed with 990 grams (approximately 990 c.c.) of water. 

93. When thoroughly mixed, cool or warm to the temperature 
selected as the standard, and fill the container A, Fig. 31, to the 
mark, having first clamped the bottom and poured in water to 
the level of the wire screen B. The cover is then screwed on, 

with the cock open ; with cover closed, 
the cock is closed, and there is no air 
pressure in A. The container is 
placed over the funnel C, a vessel is 
placed under the bottom outlet D, 
and the side outlet E is supplied with 
a graduated cylinder F. The bottom 
of the container is opened quickly and 
kept from swaying back, and the cock 
in the cover is immediately opened. 
Water at once flows into the funnel, 
rapidly at first, then at a diminishing 
rate. While the rate of flow to C ex- 
ceeds the capacity of outlet D the 
excess overflows through E to the 
graduated cylinder F. When the 
rate of flow to C falls below the capa- 
city of outlet D, the overflow through 
E is automatically cut off. In the 
case of free stock, this cut-off from E 
is relatively late; in case of slow 
stock it is relatively early. Free stock 
will dehver more water to graduated 

cylinder F than will slow stock. The amount of water in /^ is a 

measure of the freeness of the stock. 

Curves showing the variation in freeness can be drawn, and 

results can be fairly well duplicated with respect to those qualities 

controlled or indicated by this measurement. 

94. A small v^entrifuge may be used for de-watering the sample, 
giving a uniform fiber content. Charts and curves may be 
prepared for correcting results of tests, both for temperature 
and for consistency. By using such correction factors instead 
of waiting to bring conditions of test to standard, fairly accurate 
indications tnay be obtained much more quickly. 

Fig. 31. 



(1) Explain the operation of the roll counterpoise. What advantage is 
taken of this principle in the Wallace-IMasson attachment? 

(2) Describe one type of continuous beater attachment. 

(3) How does the beaterman know how close the roll is to the bed-plate? 

(4) What differences in beating would produce a soft paper or a hard, rattly 
paper from the same furnish of stock? 

(5) (a) Why is loading used in some papers? (b) Should loading be 
considered adulteration? 

(6) What parts of the beaterman's duties could be served better if he had 
some knowledge of chemistry? 

(7) In what way would you consider the microscope helpful in controlling 
the beating operation? 

(8) How is freeness (or slowness) measured, and what does the result 
obtained indicate? 




95. Importance. — The refining engine, as shown at H in Fig. 20, 
is not a necessary part of the beating equipment; but, because 
of its usefulness as a means of preparing a stock that will form well 
on the paper machine, it is found in all mills of large production, 
and in most fine mills; while in mills maldng a low grade of paper, 
it has surpassed in importance the beater itself. The most 
common type of refining engine is the Jordan, named after its 

96. Description. — A typical design of a Jordan engine is shown 
in Fig. 32. The working parts are conical in shape; they consist 
of a shell S, within which a plug R revolves, and to which it fits. 
Plug R is rigidly attached to a shaft, which turns in three bearings 
B, and is driven (in the case of a belt drive) by pulley P. Many 
Jordan engines are now installed to be direct-driven by electric 
motor, in which case, the motor is placed in line with the shaft 
of the Jordan, and is direct-connected to it bj' means of a special 
coupling, which permits horizontal movement of the plug, toward 
or from the motor. In some designs of direct drive, motor, 
plug shaft and plug, move together. 




The Jordan is adjusted to govern its action on the stock by 
moving the plug horizontally, thus bringing its surface nearer to 
or farther from the inside surface of the shell. This action is 
similar in effect to the adjustment of the beater, when the roll is 
moved toward, or from the bed-plate. In the case of the beater, 
the surface of contact between the roll and bed-plate is very 
narrow — almost a line — while in the Jordan, the surface of 
contact is the entire inside surface of the shell. In the beater, 
the direction of movement of the roll during adjustment is at 
right angles to the axis of the roll; but in the Jordan, it is parallel 
to the axis of the plug. To effect this latter movement, the 

Secfion A-A 

Fig. 32. 

bearing shown at the large end of the cone is a thrust bearing, to 
enable it to withstand pressure action lengthwise along the shaft 
as well as to support the shaft from underneath. This thrust 
bearing is connected to a worm screw, w^hich is fastened to the 
frame of the engine, and is operated by turning the hand wheel 
H. When the hand wheel is so turned that the plug, and the 
shaft to which it is keyed, move to the left. Fig. 32, the plug is 
set harder into the shell. The bearing boxes are fitted to run 
in machined ways W, in the same manner as the tool stand on 
a lathe. 

97. The necessity for the thrust bearing is due to the fact that 
the plug is conical instead of being cyhndrical. Since the surface 
of the plug makes an angle with the axis instead of being parallel 
to it (as in the case of a cylinder), any pressure acting on the 
surface may be resolved into two components, one of which will 
act parallel to the axis and the other perpendicular to it. The 
force exerted by the first component is the one that is resisted by 


the thrust bearing. The larger the angle that an element of the 
cone makes with the axis the greater will be the horizontal 

As has been stated, the beater is furnished and dumped 
alternatel}', a batch process; but the Jordan takes its supply 
from a chest, which is a supply reservoir, and runs continuously. 
The stuff from the flow box enters at A, Fig. 32, at the small end 
of the cone, and is discharged at D, at the large end. Both A 
and D are machine finished, to receive flanged pipe connections. 
The rotation of the plug at a relatively high speed, causes the stuff 
to swirl between it and the shell, and the result of this swirling 
is to cause the stuff to be thrown toward the large end of the shell 
by centrifugal force. The stuff passes through the Jordan in the 
form of a rather thin mixture, and it behaves very much like 
water. It is under considerably greater pressure at the large end 
of the cone, therefore, than at the small end, and the Jordan is 
consequently capable of throwing it up in the discharge pipe to a 
considerable height. The Jordan thus acts somewhat like a 
centrifugal pump. Both the Jordan and the beater employ the 
working parts to propel the stock, the latter by acting like a 
paddle wheel, and the former by acting like a centrifugal pump. 

98. A view of the plug alone is shown at (h), Fig. 37. It is 
fitted with bars or knives K, which are set in slots, milled in the 
webs that support the roll (plug). These bars are firmly held in 
place by wooden strips L, wedged in between them when dry. 
The construction is like that of the beater roll, except that the 
Jordan plug is conical. The large end of the cone (plug) is fitted 
with more bars than the small end, because its higher peripheral 
speed produces correspondingly higher rate of wear. 

The shell S is also fitted on the inside with bars similar to those 
of the plug. Evidently, some means must be adopted to prevent 
the bars of the plug from locking with those of the shell; this is 
usually accomplished by setting the shell filling so it slants, first 
one way and then the other, in herring bone style. Jordan 
engines, and other refiners, are sometimes arranged in series 
where more than one is provided for one paper machine. Less 
commonly they are placed in parallel. 

99. Origin of the Jordan. — The Jordan refining engine is a 
development of an earlier machine patented by T. Kingsland, of 
Franklin, N. J., in 1856. The Kingsland engine was a flat disk. 


with blades or teeth on both sides, set on a shaft, run in contact 
with two stationary disks, one on each side, which were fitted with 
similar corrugations. It was in use in the mills of T. & R. 
Kingsland, and was said to have produced some of the finest 
book and "flat cap" on the New York market. The intention 
of the inventor was to devise a continuous process of beating that 
would supplant the beater. 

In 1858, the conical refining engine was patented by Joseph 
Jordan, a paper-mill superintendent, and Thomas Eustice, a 
resident of Hartford, Conn. Many of the original experiments 
leading to the perfection of the machine were carried out by 
Jordan at Cumberland Mills, Me., in a book-paper mill, operated 
by S. D. Warren & Company, and the work was much facilitated 
by the encouragement of John E. Warren. Jordan's work was 
another attempt to supplant the beater; but, although this was 
not accomplished, the work was so well done, nevertheless, that 
the Jordan refining engine has come down to the present day with 
no important modifications. 

100. Caution. — If the refining engine is of the Jordan type, 
that is, conical, it must never be left running without a supply of 
water passing through it to cool it; for it will heat very rapidly 
when running dry, no matter how far out the plug is pulled. In 
operation, it is kept cool by the stuff. 


101. The Pope Refiner. — Although the Jordan is, by far, the 
most common single type of refining engine, there are various 
modifications of it in use, none of which, however, get very far 
from the principle of the Jordan. 

Proceeding on the general design of the Kingsland, which was 
a flat disk that revolved on a horizontal shaft, the Pope refiner 
develops a single face of contact between the disk and the 
stationary plate, instead of the double contact emploj^ed in the 
older Kingsland engine. Further, the Pope is run at an exceed- 
ingly high speed, and there is very little clearance between the 
disk and the plate. The setting of the disk against the plate 
is as positive as in the case of the Jordan, the object being to 
prevent any yielding when small bodies of material enter that are 
coarser than the distance between the disk and plate, and to 


maintain the fixed plate distance, thus reducing the size of such 
bodies to a practically uniform fineness. It was the intention 
of the inventor to bring foreign particles found in the stock to 
such fine dimensions that they could be incorporated in the 
final paper without detracting from its appearance. 

102. The Claflin Refiner. — The Claflin refiner stands between 
the two extremes of Jordan and Pope refiners; it takes the form 
of a cone, with a wide angle, and it is, consequentl}^ very short. 
The purpose of the Claflin is identical with that of the Pope, 
and its design is like a very short, stubby Jordan. Its plug and 
shell are filled in a manner similar to the Jordan. In practice, 
it is frequently set up in series, a number of separate machines 
taking the stuff, one after the other. This machine is illustrated 
in Section 8, Vol. III. 

103. The Marshall Refiner. — The Marshall refiner embodies 
some of the features of both the Jordan and the Pope, or Kings- 
land; it is a machine of the same size and weight as the Jordan. 
At the large end of the cone, however, the shell is faced with 
an annular ring, the position of which is at right angles to the 
center line of the shaft; and the plug is provided with a similar 
annular ring, which takes the form of a shoulder or collar. Both 
of these rings are filled with bars or knives. The plug is set in 
hard against the shell, which brings this annular ring in contact 
also; and the stock, which is thrown from the small end of the 
cone to the large end, passes through this annular ring last, 
thus encountering more working surface than is provided in the 

104. The Wagg Jordan. — In the wearing down of the bars of 
the Jordan engine, it often happens that much of the knife edge 
of the bars becomes dulled. It can readily be seen that neither 
the plug nor the shell will wear out in straight lines. Owing 
to the different peripheral speeds at different cross sections 
of the cone, the knives tend to wear in spots; and the spots in 
which the wear has been slower will tend to hold the plug and 
shell apart at the points where the wear has been more rapid. 
This is the explanation of the "howl," which is heard, some- 
times, for long distances from the mill. The result on the 
knives is that, where they are not in perfect contact, they erode 
under the scouring action of the stuff, and then become all the 
less effective. To obviate this, the Wagg fiUing was devised. 


This consists of bars set in pairs, instead of being equally spaced, 
the two bars of a pair being not more than the thickness of the 
steel apart. If the forward bar erodes, the follower bar, being 
protected from the scouring, keeps more nearly to its original 

105. The Jordan Drive. — The preferable drive for the Jordan 
is a direct-connected induction motor, because of the ease of 
control through the electric-power meter, and also because this 
type of drive tends to maintain ahnement. A belt drive, on the 
contrary, tends to wear the bearings in the direction of the belt 
pull, which causes the plug to work harder against one side of the 
shell than against the other side. In the case of stoppage of 
power in the beater room, the beater rolls must all be raised and 
the Jordan plugs pulled out, so that when the power is again 
applied, it will not operate at first against a full load. 

106. Conclusion. — The beaterman's duties do not end when 
the stuff he has prepared passes from the Jordan engine to the 
machine chest; his responsibilitj'- continues until the stock is 
made into a satisfactory sheet. This necessitates close cooper- 
ation between the beaterman and the machine tender; each 
ought to understand the work of the other. The refining engine, 
serving largely as a fitter of beaten stock for the paper machine, 
comes near to the machine-tender's sphere; in some mills the 
refiner is in the machine-tender's charge. Whatever the line 
of division, however, cooperation and harmony are the keys to 


(1) Make a pencil sketch of a Jordan engine and tell how it works. 

(2) Describe one type of refining engine other than the Jordan. 

(3) Should the beater room and the paper-machine room be considered as 
two distinct, separate, and independent departments? 




Eberhardt, Max: Wochbl. Papierfabr., Vol. 51, No. 47, pp. 3319-21; 
No. 48, pp. 3391-5, Nov. 27, Dec. 4, 1920. 

Shartle, Charles W. : Year Book, Am. Pulp & Paper Mill Supt. Ass'n, 
1920, pp. 119, 121. 

Stewart, O. C: Paper Trade J., Vol. 72, No. 24, p. 30, 1921; Paper, 
Vol. 28, No. 15, p. 14, June 15, 1921; C. A.,i Vol. 15, p. 4050. 
Beating, Concerning the Theory and Practice of. 

Beadle, Clayton: Vol. V of Chapters on Papermaking : Crosby, 
Lockwood and Son, London, 1908, pp. 182. German translation 
appeared in 1911. 
Beating, Consumption of Power in. 

Campbell, W. B.: P. P. Mag. Can., Vol. 18, No. 43, pp. 1087-8, Oct. 21, 
Beating of Pulp, Notes on the. 

Varlot, J. G.: Bull. Ind. J"'ab. Papier et Carton, No. 3, pp. 40-4, 
Feb. 1, 1920; C. A., Vol. 14, p. 1039. 
Beating of Paper Pulp, Notes on. 

Alison, Wm.: World's Paper Trade Rev., Vol. 77, No. 11, pp. 832, 
4, 6, 8, 858, Mar. 17, 1922; Paper Makers' Mo. J., Vol. 60, No. 4, 
pp. 133-6, discussion, 137-9, Apr., 1922; Paper Maker, Vol. 63, No. 4, 
pp. 481-3, Apr., 1922; Paper Trade J., Vol. 74, No. 19, pp. 55-7, 
May 11, 1922; Paper, Vol. 30, No. 21, pp. 7-10, July 20, 1922; Proc. 
Tech. Sec, Great Britain, Vol. 3, No. 1, pp. 40-6, Oct., 1922. 
Beating, The Degree of, Apparatus for Testing. 

Paper, Vol. 14, No. 5, pp. 19-20, Apr. 15, 1914. 
Beating, Testing the Degree of. Apparatus for. 

Schopper, Alfred: Papier-Ztg., Vol. 39, pp. 642-5; C. A., Vol. 8, p. 1502. 
Beating, Chemical Changes during. 

Schwalbe, Carl G.: Wochbl. Papierfabr., Vol. 51, No. 21, pp. 1486-9, 
May 29, 1920; Chem.-Ztg., Vol. 44, p. 458, 1920, Vol. 45, No. 53, 
p. 1883, 1920. 
Beating, Developments in. 

Green, Arthur B.: Paper, Vol. 23, No. 23, pp. 22, 24, Feb. 12, 1919. 
Beating and Beating Engines. 

Shartle, Charles W.: Paper Trade J., Vol. 75, No. 22, pp. 20, 22, 24, 26, 
Nov. 30, 1922; Paper Mill, Vol. 46, No. 47, pp. 12, 28, Dec. 2, 1922. 
Beating of Paper Pulp, the Degree of, Apparatus for Determining. 

Skark, E. W. L.: Papierfabr., Vol. 11, p. 1358; C. A., Vol. 8, p. 1205. 
Beating, the Degree of. Can the Water Retained in a Pulp Serve as a 
Criterion for. 
Skark, E. W. L.: Papierfabr., Vol. 11, pp. 1381-9, 1417-25; C. A., 
Vol. 8, p. 1502. 

' C. A. refers to Chemical .\bstracts, published semi-monthly by the American Chemical 
Society; J. S. C. I. means Journal Society of Chemical Industry; P. P. Mag. Can. means 
Pulp and Paper Magazine of Canada. 


Beating, Determining the Degree of. 

Skark, E. W. L. : Papierfabr., Vol. 19, No. 23, pp. 569-76, June 10, 1921. 
Beating of Paper Pulp, New Process for Determining the Degree of. 

Skark, E. W. L.: Papierfabr., Spec. No., 1914, pp. 87-92, Vol. 12, 
pp. 743-7; C. A., Vol. 8, p. 3117; Papierfabr., Vol. 20, No. 25, pp. 
845-52, June 25, 1922; Paper Trade J., Vol. 75, No. 21, pp. 53-5, 
Nov. 23, 1922. 
Beating Tests. 

Sutermeister, E.: Paper, Vol. 23, No. 14, pp. 11-3, Dec. 11, 1918; 
P. P. Mag. Can., Vol. 17, No. 3, pp. 47-9, Jan. 16, 1919; C. A., 
Vol. 13, p. 260. 
Beating Tests for Paperinaking Fibers. 

Sutermeister, E.: Paper, Vol. 17, No. 9, pp. 11-8, Nov. 10, 1915; 
C. A., Vol. 10, p. 525. 
Beating, Sizing, and Loading. 

Teren, George: Paper Ind., Vol. 3, pp. 710-13,1921; C. A., Vol. 15, p. 4050. 
Beating, Theory and Practice of, Remarks on. 

Beadle, Clayton: Papierfabr., Vol. 10, No. 49, pp. 1393-9, Dec. 6, 
Beating, Power Consumption in. 

Beadle, Clayton: Paper, Vol. 10, No. 1, pp. 15-18, 34, Dec. 18, 1912. 
Beating, Today and Tomorrow. 

Campbell, W. B.: Paper, Vol. 27, No. 25, pp. 25-6, 32, Feb. 23, 1921; 
Paper Maker, Vol. 62, No. 1, pp. 37, 39, July, 1921; P. P. Mag. 
Can., Vol. 19, No. 3, pp. 65-67, 1921. 
Beating and Hydration. 

Cyster, F.: World's Paper Trade Rev., July 16, 1915; Paper, Vol. 16, 
No. 22, pp. 13-4, Aug. 11, 1915; C. A., Vol. 9, p. 3129. 
Beating, Some Methods for the Study of. 

Green, Arthur B.: Paper, Vol. 17, No. 24, pp. 21-8, 1916; C. A., Vol. 
10, p. 1432. 
Beating, Viscosity Principle in. 

Green, Arthur B.: Paper, Vol. 21, No. 7, pp. 17, 34, Oct. 24, 1917. 
Beating of Sulphite Pulp, Experiments in the. 

Kress, Otto, and McNaughton, G. C. : Paper, Vol. 20, No. 17, pp. 13-7, 
July 4, 1917; C. A., Vol. 11, p. 2542. 
Beating Problems. 

Leicester, Sheldon: World's Paper Trade Rev., Vol. 77, No. 14, pp. 
1066-8, Apr. 7, 1922. 
Beating, the Time of. Effect of Certain Chemicals on. 

Mansfield, E. K, and Stephenson, J. N.: P. P. Mag. Can., Vol. 14, 
No. 19, pp. 325-7, Oct. 1, 1916; Paper, Vol. 19, No. 8, pp. 17-9, 
Nov. 1, 1916; C. A., Vol. 11, p. 887. 
Beating Conditions as Affected by the Temperature of the Water. 
Hatch, R. S.: Paper, Vol. 19, No. 20, pp. 18-9, Jan. 24, 1917. 
Beating Engine, Theory of the. 

Haussner, Alfred: Papierfabr. Spec. No., 1913, pp. 46-51; C. A., 
Vol. 7, p. 3839. 
Beating Requirements for Cigarette Paper (see Cigarette Paper). 


Beater, The Story of the. 

Wheelwright, Wm. Bond: Alfelco Facts, Vol. 1, No. 3, pp. 5-14, 1922. 
Beater, The Action of the, in Papermaking. 

Smith, Sigurd: Paper Trade J., Vol. 75, No. 26, pp. 47-8, Dec. 28, 1922; 
Vol. 76, No. 1, pp. 49-53, Jan. 4, 1923; World's Paper Trade Rev., 
Vol. 78, No. 21, pp. 1705-6, 1708, 1710, No. 22, pp. 1810, 12, 14, 
16, Nov. 24, Dec. 1, 1922. 
Beater, The, in Great Britain from the Engineering Point of View. 

Nuttall, T. D.: Proc. Tech. Sec, Great Britain, Vol. 1, No. 2, pp. 180-5, 
Aug., 1921; Paper Trade J., Vol. 74, No. 6, pp. 48-9, Feb. 9, 
Beater, New Niagara, Development of the. 

Burns, W. H.: Paper, Vol. 27, No. 19, pp. 13-4, Jan. 12, 1922. 
Beater Consistency Changes, A Study of. 

Gesell, W. H., and Minor, Jessie E.: Paper, Vol. 24, pp. 443-7, 1919; 
C. A., Vol. 13, p. 1765. 
Beater Furnish, Report of Committee on. 

Miller, H. F.: Paper Trade J., Vol. 74, No. 23, pp. 48-50, June 8, 1922; 
Paper, Vol. 30, No. 20, pp. 7-10, July 19, 1922; Paper Mill, Vol. 
45, No. 21, pp. 14, 16, 78, June 3, 1922. 
Beater Sizing, Function of Starch in. 

Traquair, John: Paper, Vol. 21, No. 23, pp. 68, 70, Feb. 13, 1918. 
Beater Room, Management in the. 

Green, Arthur B.: Paper, Vol. 19, No. 23, pp. 19, 20, 22, 24, 26, 28, 30, 
32, 34, 36, 38, 40, 54, Feb. 14, 1917. 
Beaters, Notes on the Efficiency of. 

Schhck, Leo: Paper, Vol. 15, No. 14, pp. 18-21, 38, Dec. 16, 1914; 
P. P. Mag. Can., Vol. 12, No. 22, pp. 647-52, Nov. 15, 1914. 
Beaters, Power Consumption of, Calculating the. 

Bouvier, F. M.: Moniteur de la Papeterie Francaise, Vol. 52, pp. 788- 
790, Dec. 15, 1922; Paper Trade J., Vol. 74, No. 13, pp. 4.5-6, Mar. 30, 
1922; Zellstoff. u. Papier, Vol. 2, No. 2, pp. 37-40, Feb., 1922. 
Beaters, Roll Pressure of. Standardization and Measurement of the. 

Muller, : Zellstoff u. Papier, Vol. 2, No. 1, p. 22, Jan., 1922; 

P. P. Mag. Can., Vol. 20, p. 564, July 6, 1922. 
Beater? Why is a. 

Schlick, Leo: P. P. Mag. Can., Vol. 17, pp. 1024-5. 
Cellulose, Colloidal Properties of. 

Minor, Jessie E.: Paper, Vol. 25, No. 14, pp. 700-3, 1919; C. A., Vol. 14, 
p. 344. 
Cellulose, The Constitution of. 

Gesell, W. H., and Minor, Jessie E.: Paper, Vol. 24, pp. 527-9, 1919; 
C. A., Vol. 13, p. 1925. 
Cellulose, Cotton, Action of Water and Alkali upon. 

Schwalbe, Carl G., and Robinoff, Michael: Z. angew. Chem., Vol. 24, 
pp. 256-8; C. A., Vol. 5, p. 1838. 
Cellulose, Reactions of. 

Seibert, Florence B., and Minor, Jessie E. : Paper, Vol. 24, No. 23, pp. 
1007-12, Aug. 13, 1919; C. A., Vol. 13, p. 2440. 


Cellulose, Contribution to the Knowledge of. Hydrocellulose. 

Jentgen, H.: Z. angew. Chem., Vol. 23, pp. 1541-6; Vol. 24, pp. 11-2; 
C. A., Vol. 5, pp. 1187, 1677. 
Cellulose Hydrate — A Contril)ution to the Knowledge of the Decomposition 
of Mordanting Salts by Cellulose. 
Schwalbe, Carl G.: Z. angew. Chem., Vol. .32, I, pp. 355-7, 1919; 
C. A., Vol. 14, p. 1437. 
Cellulose, Hydration of, During Beating. 

Briggs, J. F.: Papierfabr., Special No., 1910, pp. 46-9. 
Cellulose Mucilage. 

Minor, Jessie E.: J. Ind. Eng. Chem., Vol. 13, pp. 131-3, 1921; C. A., 
Vol. 15, p. 1212. 
Cellulose Mucilage, Study of. 

Schwalbe, Carl, and Becker, Ernst: Z. angew. Chem., Vol. 32, I, pp. 
265-9, 1919; Vol. 33, I, pp. 57-8, 1920; C. A., Vol. 14, pp. 837. 3790, 
Chemistry, Fundamental, in Paper Making, with a Note on the Chemistry 
of the Beating Process. 
MacDonald, J. L. A.: World's Paper Trade Rev., Vol. 76, Nos. 13, 14, 
1921; Chem. Trade J., Vol. 69, pp. 397-9, 1921; P. P. Mag. Can., 
Vol. 19, No. 42, 1067-9, Oct. 20, 1921; Paper Mill, Vol. 44, No. 46, 
pp. 18, 20, 90, Nov. 5, 1921; Proc. Tech. Sec, Great Britain, Vol. 2, 
No. 2, pp. 132-42, Mar., 1922. 
Cigarette Paper, Beating Requirements for. 

Paper, Vol. 23, No. 20, pp. 11-3, Jan. 22, 1919. 
Colloid Chemistry and Papermaking. 

Rohland, P.: Wochbl. Papierfabr., Vol. 44, pp. 2075-7; Paper Maker, 
Vol. 46, No. 5, p. 762, Nov., 1913; Paper, Vol. 12, No. 11, p. 21, 
Aug. 27, 1913; P. P. Mag. Can., Vol. 12, No. 2, p. 45, Jan. 15, 1914. 
Colloidal Chemistry as Applied to the Paper Industry. 

Darrah, W. A.: Paper Ind., Vol. 1, No. 12, pp. 1137-41, 1160-9, Mar., 
Colloidal Chemistry in Papermaking, The Function of. 

DeCew, Judson A.: J. S. C. I., Vol. 36, pp. 357-9, 1917; Paper, Vol. 20, 
No. 11, pp. 13-5, May 23, 1917; Paper Maker, Int. No., 1916-1917, 
pp. 44-5, 47; Sci. Am. Sup., Vol. 84, pp. 191-2, Sept. 22, 1917; C. A., 
Vol. 11, p. 1901. 
Colloidal Chemistry in Papermaking. 

Bovard, W. M.: Paper, Vol. 22, No. 3, pp. 11-6; P. P. Mag. Can., Vol. 
16, pp. 729-31, 740, 751, 766, Aug. 15, 22, 1918; C. A., Vol. 12, 
p. 1251. 
Consistency of Stock and White Water, Relation between the, on Paper 
Trimbey, Edward J.: P. P. Mag. Can., Vol. 13, No. 2, pp. 34-7, 
Jan. 15, 1915. 
Density of Pulp and its Relation to the Beater. 

Paper Trade J., Vol. 60, No. 10, p. 52, Mar. 11, 1915; P. P. Mag. Can., 
Vol. 13, No. 7, p. 206, Apr. 1, 1915; Paper Maker, Vol. 50, No. 2, 
p. 188, Aug., 1915. 


Freeness Testing of Pulp. 

Williams, F. M.: Paper Trade J., Vol. 74, No. 23, pp. 43-4, June 8, 
1922; Paper Mill, Vol. 45, No. 21, pp. 26-7, June 3, 1922; Paper, Vol. 
30, No. 19, pp. 10-11, July 12, 1922; World's Paper Trade Rev., Vol. 
78, No. 3, p. 206, July 21, 1922. 
[Freeness Tester] Apparatus for Determining the "Freeness" of Paper Stock. 
Ivirchner, E.: Wochbl. Papierfabr., Vol. 44, pp. 3694-7; C. A., Vol. 8, 
p. 246. 
Furnish to Beaters, Proper Order of Adding. 

Sunderland, A. E.: Paper, Vol. 20, No. 4, pp. 13-6, Apr. 4, 1917; 
C. A., Vol. 11, p. 1544. 
"Greasy" or "Free" Stuflf. 

Ivirchner, E.: Wochbl. Papierfabr., Vol. 44. pp. 3517-20; C. A., Vol. 8, 
p. 246. 
Hazards, Beater-Room. 

Walker, Charles: Paper Trade J., Vol. 73, No. 14, p. 46, Oct. 6, 1921; 
Paper, Vol. 29, No. 6, pp. 9-10, Oct. 12, 1921; P. P. Mag. Can., 
Vol. 20, No. 16, pp. 317-8, Apr. 20, 1922; World's Paper Trade Rev., 
Vol. 77, No. 24, p. 1876, June 16, 1922. 
Heating of Stuff in the Beater. 

World's Paper Trade Rev., Vol. 78, No. 2, p. 100, July 14, 1922; Paper 
Makers' Mo. J., Vol. 60, No. 1, p. 7, Jan. 16, 1922. 
Hollander, The Action of the, upon Pulp. 

Smith, Sigurd: Papierfabr., Vol. 18, No. 32, pp. 591-4, Aug. 6, 1920. 
Hollander, The Beating Process in the. 

Sellergren, G.: Papierfabr., Vol. 18, No. 32, pp. 59i-6, Aug. 6, 1920. 
Hollander, Development of the. 

Blau, Ernst: Papierfabr., Vol. 19, No. 28, pp. 721-7, No. 29, pp. 753-7, 
July 15, 22, 1922. 
Hollander, Rational Theory of the. 

Smith, Sigurd: Papierfabr., Vols. 18, 19, 1920, 1921. ' Reprinted as 
"Die Rationelle Theorie des GanzzeughoUanders," by Otto Eisner 
Verlagsgesellschaft, 1922, 192 pp. Arrangements have been made by 
the Tech. Ass'n of Great Britain to translate the work into English. 

Panaitopol, Geo.: Wochbl. Papierfabr., Vol. 38, pp. 3736-40, Nov., 
1907; C. A., Vol. 2, p. 586. 
Hollanders and their Po\yer Consumption. 

Pfarr, A.: Wochbl. Papierfabr., Vol. 38, pp. 3032-9, 3111-6, 3185-90, 
3261-5, 1907. 
Hollanders, The Theory of. 

Krchner, E.: Wochbl. Papierfabr., Vol. 38, pp. 3983-6, 4062-7, Dec. 
14, 1907. 
Hollander Beater, Consideration of the. 

Kirchner, E.: Wochbl. Papierfabr., Vol. 49, pp. 282-3, 423-4; C. A., 
Vol. 14, p. 122. 
Hollander Drives and Self-Regulation of the Hollander. 

Stiel, Wilhelm: Wochbl. Papierfabr., Vol. 51, No. 14, pp. 993-5; No. 15, 
pp. 1066-9, Apr. 10, 17, 1920. 


Hollander Considerations. 

Haussner, Alfred: Wochbl. Papierfabr., Vol. 52, No. 21, pp. 1628-33, 
No. 27, pp. 2176-80, No. 31, pp. 2495-8, No. 33, pp. 2661-4, No. 39, 
pp. 3179-83, No. 44, pp. 3605-7, No. 48, pp. 3965-7, No. 49, pp. 
4049-52, 1921. 
Hollander Construction and its Influence upon the Beating Effect. 

Kirchner, E.: Wochbl. Papierfabr., Vol. 51, No. 23, pp. 1626-8, No. 25, 
pp. 1770-2, June 12, 23, 1920. 
Hollander Rolls. Speed of Movement of the Pulp and Beating EflBcicncy 
of the Rolls. 
Piesslinger, Fritz: Wochbl. Papierfabr., Vol. 38, pp. 3507-10, 3585-8, 
Oct. 26, Nov. 2, 1907; C. A., Vol. 2, p. 585. 
Hj'drating Machinery for the Paper Mill. 

Bidwell, George L.: Tech. Assoc. Papers, Vol. 5, No. 1, pp. 7-8, 1922; 
Paper Trade J., Vol. 74, No. 15, pp. 191, 193, Apr. 13, 1922; Paper 
Mill, Vol. 45, No. 14, p. .54, Apr. 15, 1922; Paper, Vol. 30, No. 7, 
pp. 53-4, 56, Apr. 19, 1922; Paper Ind., Vol. 4, No. 1, pp. 78-80, 
Apr., 1922; Boxboard, Vol. 1, No. 5, pp. 16-18, May, 1922. 
Hydration, Effect of, on the Retention of Stuff". 

Cyster, F.: Paper Making, Vol. 34, pp. 487-9; Paper, Vol. 15, No. 15, 
pp. 17, 38, Dec. 23, 1914; Paper Trade J., Vol. 59, No. 26, p. 52, 
Dec. 31, 1914; C. A., Vol. 9, p. 1843. 
Hydration in Papermaking Processes. 

Beadle, Clayton, and Stevens, H. P.: J. S. C. I., Vol. 32, pp. 217-8; 
P. P. Mag. Can., Vol. 11, No. 9, pp. 295-6, May 1, 1913; Paper, Vol. 
11, No. 5. pp. 19-20, Apr. 16, 1913; C. A., Vol. 7, p. 2305. 
Hydration of Cellulose During Beating (see Cellulose). 
Hydration of Pulp, Chemical. 

MacKay, Alfred: Paper, Vol. 29, No. 16, pp. 7-10, Dec. 21, 1921. 
Hydration of Sulphite and Esparto Pulps. 

Papeterie, Vol. 43, pp. 146-9, 1921; C. A., Vol. 15, p. 1620. 

Schwalbe, Carl G.: Z. angew. Chem., Vol. 23, pp. 2030-1; Vol. 24, p. 12; 
C. A., Vol. 5, pp. 1187, 1677. 
Length of Cotton and Linen Fibers, Diminution in, During the Preparation 
of Stuff for the Manufacture of Paper. 
Beadle, Clayton, and Stevens, H. P. : Chem. News, Vol. 96, pp. 139-40, 
Sept., 1907; C. A., Vol. 2, p. 586. 
Mucilage of Parchment Paper Pulps. 

Seibert, Florence B., and Minor, Jessie E.: P. P. Mag. Can., Vol. 18, 
pp. 930-42, 1920; C. A., Vol. 15, p. 2183. 
Power Consumption of Beaters. 

Schulte, H.: Zentr. Oesterr-ungar. Papierind., Vol. 28, p. 871, 1914; 
Paper, Vol. 15, No. 24, pp. 15-16, Jan. 27, 1915; C. A., Vol. 9, p. 1114. 
Power Consumption of Beaters, Calculating the (see Beaters). 
Power Consumption, Influence of, during Beating on the Strength and Ash 
Content of Paper. 
Fotieff, S.: Papierfabr., Vol. 11, pp. 1263-7; C. A., Vol. 8, p. 1502. 


Power Consumption when Beating Half-Stuff and Whole Stuff. 

Rehn, Arnold: Papierfabr., Spec. No., 1912, pp. 68-81, No. 37, pp. 
1051-8. No. 38, pp. 1079-83, No. 39, pp. 1106-9, S-pt. 13-27, 1922; 
C. A., Vol. 6, p. 2526, Vol. 7, pp. 889, 2855; P. P. Mag. Can., Vol. 11, 
No. 19, pp. 651-7; No. 20, pp. 680-5, Oct. 1, 15, 1913, No. 21, pp! 
709-13, Nov. 1, 1913. 
Safety in the Beater Room. 

Drumb, Frank A.: Paper Ind., Vol. 4, No. 5, pp. 652-5, Aug., 1922. 
Slowness Tester, Green's. 

P. P. Mag. Can., Vol. 20, No. 36, p. 765, Sept. 7, 1922. 
Soda Consumption and Time of Beating, Influence of, on Paper. 

Beadle, Clayton, and Stevens, H. P.: Paper, Vol. 11, No. 2, pp. 18-22, 
Mar. 26, 1913; P. P. Mag. Can., Vol. 11, No. 8, pp. 256-9. 
Temperature, The Influence of, on the Speed with which Water Drains from 
Paper Pulp. 
Smith, Sigurd: Papierfabr., Vol. 17, pp. 1121-3, 1919; C, A., Vol 14 
p. 222. 
Testing the Condition of Paper Stuff. 

Klemm, Paul: Wochbl. Papierfabr., Vol. 38, pp. 3822-32, 3986-7, 
1907; C. A., Vol. 2, p. 588. 
Tester, Schubert's, for the Degree of Beating. 

Zellstoff u. Papier, Vol. 1, pp. 21-3, 1921; C. A., Vol. 15, p. 3395. 



(1) What is the purpose of beating? 

(2) Name the principal parts of the modern Hollander. 

(3) How is the batch sj^stem of operating beaters converted 
into continuous operation for the paper machine? 

(4) Make a pencil sketch of a pulp mixer and explain how it 

(5) (a) What should be the size of a stuff chest? (6) What are 
the principal requirements of a good stuff chest? 

(6) If the stuff in a Jordan chest is of 3% consistency and its 
weight is taken as 62.5 lb. per cu. ft., at how many revolutions per 
minute must the crank shaft of a single-acting, simplex pump 
turn to throw 1 ton (2000 lb.) of bone-dry stock per hour, allow- 
ing 10% for leakage in the pump? The diameter of the pump 
cyhnder is 8 in. and its stroke is 12 in. Ans. 63 r.p.m. 

(7) (a) How can uniformity of consistency be obtained when 
furnishing beaters? (b) Of what benefit is it to secure this 

(8) What should be done with the beaters and Jordans in case 
of interruption of power? 

(9) State the usual order of furnishing the beater. 

(10) Define: (a) bed-plate; (6) back-fall; (c) lighter; (d) free 
stock; (e) slow stock; (/) hydration. 

(11) Describe some changes in the fiber as the beating 

(12) Do you think anj' type of refiner that is described in this 
Section can perform all the functions of a beater? Explain your 

(13) A certain beater has a capacity of 420 cu. ft. (a) If filled 
with stuff at 5 % consistency, how many pounds of bone-dry fiber 
§3 79 


will it hold? (6) How many pounds of wet laps of pulp, 30% 
bone dry, must be used to fill this beater to the above consistency? 
(c) How many pounds of water must be added with the laps of 
pulp? Assume that both the stuff and the wet laps weigh 62.5 
lb. per cu. ft. f (a) 1181.25 lb. 

Ans. \ (b) 3937.5 lb. 
i (c) 22312.5 1b. 



(PART 1) 

By Ross Campbell, B. S. 



1. Why Paper Contains Substances Other than Fiber. — Fiber 

is, of course, the chief constituent of all paper. If, however, 
fiber were the only substance entering into its composition, the 
usefulness of paper would be very much restricted, as the sheet 
would be soft, of a yellowish color, and could not be written on 
with a pen; printing ink would not "take well" on it. If the 
sheet were thin, it would be so transparent that words written or 
printed on one side of it could be read through the sheet. An 
example of paper made of especially pure fiber is filter paper. 
It is necessary, then, to add many other substances to the fiber 
to produce paper suited to the many uses to which it is put; and 
among these substances are sizing, coloring, and fillers or loading. 
(Loading properly means the adding of a filler, but the term is 
also applied to the substances added.) If a sheet were made in 
the same manner as the average book paper, but without adding 
a filler, it would be found to be more translucent; i.e., the printed 
letter would show through, and it would not, as a rule, take fine 
line cuts as clearly as it would if a filler had been added. The 
principal features in connection with the use of fillers will be 
treated in this Section. 
§4 1 


2. What Fillers Are and Why They are Used. — All fillers are 
mineral substances: they may be (a) a natural product, as talc, 
which is merely a particular kind of rock, properly ground and 
bolted (screened); or (6) a manufactured article, as crown filler. 
Many substances used as fillers are also used for coating paper 
and boards; this latter use is not considered in the Section. 

Although it usually has the effect of making paper less costly, 
filler is not, in general, added to paper for the purpose of cheapen- 
ing it; its primary purpose is to secure qualities not otherwise 
obtainable. The largest quantities of filler are probably used in 
book papers, where it is desired to produce an opaque sheet that 
has good ink-absorbing properties and a very smooth and even 
surface for taking haK-tone cuts; in this case, the presence of 
filler improves the surface, especially when the paper is super- 
calendered. The filler occupies the spaces between the fibers, 
so that the whole surface gets approximately the same pressure 
and friction from the calender. In papers of this kind, the 
amounts of filler added to the beaters vary from 5% to 40% for 
clay, and 5% to 20% for talc and agalite; the average is 10% to 
15% for all kinds of fillers. In the case of papeteries, where a 
ver}'- high color and delicate tints are frequently desired, a filHng 
or loading substance, as crown filler, having a higher color than 
the stock, is of very great use. Many special industrial papers 
must be loaded, some of them very heavily, in order to fulfill 
their special requirements; as an example, stereo-matrix board 
may be mentioned. In practice, this latter is built up by pasting 
several sheets together, the whole being then covered by a special 
and very tough tissue paper. On this, an impression is made 
from type already cast by the linotype or otherwise composed. 
After the impression is made, the matrix, as it is then called, is 
used as a mold for casting type to fit the rotary printing presses. 
In order to take a good impression without breaking, and to 
give a good cast, it is requisite that the board be properly 

In general, the presence of filler tends to decrease the strength 
and size-fastness of a sheet; but this effect is not sufficiently 
marked to be of commercial importance, unless the amount of 
filler used be large. If the strength of paper is specified, proper 
selection and treatment of the fiber must be observed. Size- 
fastness has not the same significance in printing papers as in 
writings, because printing inks have an oily medium. 




3. Names of Fillers. — There are comparatively few fillers in 
use in the paper industry in America. Those commonly met 
with are: clay, talc, agalite, crown filler, and pearl filler. For 
special purposes, small quantities of barytes (barium sulphate), 
satiii white, or chalk are used. The following table gives the 
name, chemical formula, approximate composition, and principal 
uses for fillers commonly used in the paper industry : 



„ , Analysis ., 
Formula , .. s Lse 

Natural Fillers: 


46% SiOj 
40% AI2O3 
14 % H2O 

(1) Book 

(2) Coating 

(3) Lower-grade writ- 

2. Talc 


63 % Si02 

32% MgO 

5% H2O 

(1) Lower-grade writ- 

(2) Book 

3. Agalite 


63% Si02 

32% MgO 

5% H2O 

Same as talc 

4. Pearl filler (terra alba) CaS0< 

(1 ) Lower-grade writ- 


5. Barytes (heavy spar) j BaSOi 

(1) Coatings 
(2)Litho papers 
(chiefly abroad) 
(3) Photographic 

6. Chalk CaCOa 

(1) Cigarette 

Artificial Fillers: 

1. Crown filler (pearl harden- CaSOi-2H50 

(1) Writings 

(2) Superfines 

(1) Cigarette 

3. Blanc fixe (artificial heavy 


(1) Coating 
(2)Litho papers 
(chiefly abroad) 
(3) Photographic 

+ Ah(OH)a 


29 % SOi 
13% khOz 
39 % CaO 
19 % loss on 

(1) Coating 




4. How Produced. — Clay, known also as kaolin and china 
clay, is formed by the weathering or gradual disintegration of a 
certain kind of rock called feldspar; it is one of the most widely 
distributed of our minerals. In England, clay is mined by first 
removing the dirt, or overburden. A pit is dug in the center of 
this cleared space, and a wooden pipe is sunk in the bottom of the 
pit to a depth of about 100 feet. The bottom of this pipe is 
connected to pumping machinery. The clay is washed down 
the sides of the pit, around the pipe, by means of streams of 
water. The resulting water and claj'' mixture enters the central 
pipe by holes left for the purpose. It is then pumped through 
long troughs, where the heavier impurities settle out. From the 
troughs, it flows to setthng tanks, where the water is drawn oflf 
as the clay settles, until the remaining mass is pasty. This is 
dug out and is taken to the drj-ing shed. After drying, the clay 
is ready for shipment. 

In America, the first steps in mining clay are different, two 
methods being used: (a) the open-cut method, in which the 
overburden is first removed, and the clay is dug out and shoveled 
into small cars; (6) the shaft method, in which a shaft, usually 
vertical, is sunk, and the clay is mined and hoisted to the surface. 

Regardless of the method emploj^ed in mining, the clay is then 
broken up in water; after which, it flows through a sand box and 
sand and mica troughs, to remove the heavy impurities. It is 
then screened through either stationary or shaking screens; after 
which, it is filter-pressed and dried. This wet method has been 
displaced by a dry method in some mines. In the latter case, 
the clay is taken direct from the mine to the drying shed. As 
soon as it is sufficiently dried, it is ground, and is then freed from 
heavy impurities by air separation. (See Fig. 3.) 

Much of the southern sedimentary clay is not purified. It is 
mined, dried in open sheds by exposure to the air, and is shipped 
as crude domestic cla}'. 

5. Impurities in Clay. — As would naturally be expected from 
its origin, the chief unpurities in clay from a paper-making 
standpoint are grit and iron. The presence of an excess of iron 
results in a yellowish color, which, when not too deep, is sometimes 


corrected by the use of a blue dye. English clays, for example, 
are sometimes tinted with ultramarine, to neutralize the yellowish 
color. The presence of grit is objectionable because of the wear- 
ing action on the paper-machine parts; it dulls the cutter knives, 
causes holes in the finished paper, and creates excessive wear on 
the printing plates. Some American clays are reddish-yellow 
when wet, but are white when dry; this is not an objectionable 
feature in paper making, since the color when dry should be the 
controlling factor. 

It is widely believed that for other reasons besides color, 
English clays are superior to those found here in America; it is 
generally held that the desired qualities of finish, feel, opacity, 
and ink-absorbing power cannot be obtained by using domestic 
(American) clay alone. That there is a difi'erence between 
domestic and English clays is shown by the variation in the time 
of slaking that characterizes the two groups. If lumps of 
domestic and English clay are put in a pan of water, it will be 
noticed that the time required for the water to disintegrate the 
clay lumps is much shorter for imported than for domestic 
clays. This difference is sometimes attributed to the fact that, 
while a wet process may have been used in purifying both classes, 
the English clay is allowed to settle and the water is then drawn 
off; whereas in America, filter presses are used, and the pressure 
employed in these presses is said to affect the speed of slaking. 

6. Properties of Clay. — Chemically, clay is a hydrated alumi- 
num silicate, containing approximately 40% AI2O3, 46% SiOz, 
and 14 % H2O (water). Physically, it is a yellowish to bluish- 
white substance, having a smooth, greasy feel, and possessing the 
characteristic property of making a "slip" or "slurry" on the 
addition of water. This slurry is merely a suspension of clay in 
water; but it may, at times, be almost a colloidal solution. If a 
sample of good English china clay be shaken or stirred with 
about four times its weight of water for two hours and then 
allowed to stand, it will be noticed that it settles very slowly. 
The time of stirring that is necessary will vary somewhat with the 
clay used. Talc or agalite when treated in the same way settles 
very quickly. 

Clay is the most finely divided of our common fillers; it has a 
better color than most talcs or agalites, but not as good a color as 
pearl or crown filler. The discoloration may be due to iron or 
organic matter. 



7. Quantity of Clay Used in Paper. — The quantity of clay used 
in book paper, which is the grade in which the greatest tonnage is 
used, is generally from 10% to 20% of the weight of the paper, 
although as much as 40% is sometimes found in papers that are 
to be given a very high finish, in order to take fine line-cuts or 
half-tone prints; smaller amounts, from 5% to 10%, are used in 
cheap writings, tablets, etc. Up to 5% is sometimes used in 

8. Methods of Handling. — Before clay is added to the beater, 
it is usually made up with water (1 to 2^ pounds of clay per gallon) 
and screened to remove dirt. Sometimes j% to ^ % of sodium 


Fig. 1. 
Legend: A, car; B, crusher; C\ and C2, spiral (worm) conveyors; D, bucket elevator; 
E, stairway; F, chutes to bins and tanks; G, mixing tanks; H, two storage bins, with spiral 
conveyor in the center of the bottom of each; K, 4 clay-milk storage tanks; L, automatic 
weighing hoppers; M, motors; A^, alum and size house; 0, platform; P, revolving screens; 
R, pump; T, pipe line to storage tanks. 

silicate (based on the weight of clay used) is added when mixing 
with water; this is said to reduce greatly the viscosity of the 
solution, thus making the screening easier. Other alkalis, as 
caustic soda, bring about a similar result. Care must be exercised 
in the use of such substances, because of possible undesired effects 
on other materials, as size and coloring. 

9. There are many waj'^s of handling clay; sketches of two 
arrangements are given herewith. The first of these, outlined in 
Fig. 1, gives the course of the filler from railroad car to the storage 
tanks for the clay-and-water slip (slurry). The numbers refer 



to the order or sequence of operations and the letters to the cut 
(illustration). 1, clay is transferred from cars A to a receiving 
hopper; 2, to crusher ^; 3, to elevator feeder Ci; 4, to bucket 
elevator D; 5, to distributing conveyor d; 6, to bins H; 7, to 
reclaiming conveyor; 8, to scale hopper L; 9, to bucket elevator, as 
in D; 10, to distributing conveyor; 11, to mixing tanks G; 12, to 
revolving sifter screens P; 13, to storage tanks K. 

10. A much simpler system is shown in Fig. 2. In this case, 
the clay (received in bulk) in cars A is shoveled into a chute B, 
which deposits it on a conveyor C. By this means, it is distrib- 







Fig. 2. 

uted to any part of the clay storage bin D. As needed, clay is 
drawn from storage in carts, and is mixed with water in tanks Ei 
and Ei. Each of these tanks should hold at least a 1 2-hour 's 
supply. The agitators in these tanks should run at about 
8 r.p.m. ; they should pass close enough to the bottom to keep the 
clay thoroughly stirred up. Water is run in fast, and the agita- 
tor started; then the clay is added, gradually. From the mixers, 
the clay-milk is pumped to storage tanks G, and from thence to 
the measuring tanks I, there being one of the latter for every set 
of beaters. By placing tank G on a higher level, the clay slurry 
can be run by gravity to 7, and from the latter to the beaters. 


11. Occurrence. — The largest deposits of talc are in Vermont 
and northern New York. There are a number of varieties of talc, 
several sometimes occurring together; they differ from one 
another in color, hardness, and crystalline form, which accounts 
for the non-uniformity observed in the appearance of talcs when 
examined under the microscope. In some cases, each variety is 
mined separately, but more often as they occur, without separa- 



Fig. 3. 

Fig. 4. 



Fig. 5. 

Fig. 6. 


tion. In the early days of the industry, some surface mining was 
done; but the work is almost wholly underground now. 

12. Treatment. — After the rock is brought to the surface, it is 
sorted, broken in a jaw crusher, then between rolls, and is then 
finally ground in a roller mill, a tube mill, or in an intermittent- 
operating pebble mill. The finished product is screened only, or 
is air-separated, depending on the degree of fineness required. 
Under the microscope, it is generally seen as flat plates of many 
sizes. (See Fig. 5.) 

13. Properties. — Chemically, talc is a hydrated magnesium 
silicate, giving by analysis approximately 32% MgO, 63% Si02, 
and 5% H2O (water). Physically, it is a greenish-gray substance 
having a soapy feel. Soapstone is a variety of talc. 

14. Uses. — Talc is one of the natural fillers; it is much used in 
book papers, particularly those which are not to be used for fine 
printing, as line cuts, half-tones and other delicate plates. It is 
not suited to the latter, because the comparatively sharp, hard 
particles of talc are large enough to wear the printing plates 
badly, thus causing fine lines to blur. The use of talc tends to 
soften the sheet and improve the printing qualities, but to a less 
degree than does clay. To a certain extent, a shiny appearance 
and a slippery feel is given the paper. It is generally used in 
smaller quantities than clay, from 3% to 20%, averaging 10%. 

The objections to its use are the possibility of the presence of 
grit, "shiners" (pieces of mica), carbonates, and iron. On the 
other hand, talc is cheaper than clay, has a higher retention (see 
Art. 23), and it can be added to the beater dr}^ as received; 
whereas clay must be carefully mixed with water before adding. 
Probably its most desirable use is to soften the cheaper writing, 
tablet, papeterie, and similar papers, in which it is used in quanti- 
ties of from 3% to 10%. It serves to remove that " woody" feel 
to some extent. Its color is, in general, poorer and less satis- 
factory than any of the other fillers. 


15. Agalite. — In many ways, agalite is similar to talc; chemic- 
ally, it is identical with talc. Physically, it is less soapy than 
talc, but has much the same general color. Under the micro- 
scope, it is supposed to appear as long needle-like crystals. A 
careful examination of many commercial samples of talc and 

§4 LOADING 11 

agalite has shown that these substances grade into each other 
as regards crystal form. 

The properties of agaUte, drawbacks to its use, etc. are much 
the same as in the case of talc, but the former is considered to be 
more wearing on paper-machine clothing parts and on printing 
plates ; it tends to wear the fine lines on the latter and to fill them 
with dust. For this reason, it is not used to the same extent as 
clay or talc, especially in book papers. Agalite should not be 
used in quantity in papers that are to be cut or punched, because 
it dulls the steel cutting edges. Its color is, in general, a gray, 
somewhat lighter than talc, and lacks the characteristic green 
tint of the latter. 

16. Asbestine. — Asbestine is a filler that much resembles talc 
and agalite; under the microscope, it appears as a mixture of 
these two. Its use and properties are a sort of a compromise, as 
would be expected from this crystal formation. (See Fig. 6.) 

17. Crown Filler. — Crown filler has by far the purest white 
color of any of the fillers; it is also known as pearl hardening. 
Crown filler is an artificial (manufactured) product, as distin- 
guished from clay, talc, agalite, and pearl filler, which are mined. 
It is made as a precipitate by the interaction of solutions of 
CaCl2 and NaHS04. Chemically, it is calcium sulphate, with 
two molecules of water of crystalhzation CaS04-2H20. The 
dry substance shows, on analysis, 79% CaS04 and 21% H2O. 
By water of crystallization is meant water chemically combined, 
so that a substance containing it can appear to be quite dry while 
containing, in some cases, as much as 50% water. Crown filler 
appears on the market as a wet powder that contains 33 % water, 
of which 21% is chemically combined and the remainder is 
mechanically mixed. (See Fig. 4.) 

Owing to the methods of manufacture, crown filler can be kept 
free from grit and very low in iron and in acid content. Exten- 
sive mill and laboratory tests have shown that free acid, figured 
as hydrochloric acid, should not be over 0.05%, based on the 
sample as received; more than this may cause trouble with the 
rosin sizing. It is the most soluble of the fillers, about 30 pounds 
being dissolved in 1000 gallons of pure water at ordinary room 
temperature. At this rate, from 60 to 80 pounds are dissolved 
in the water contained in an ordinary 1000-pound beater; there- 
fore, if less than 10 pounds of crown filler per 100 pounds of fiber 


are added to the beater, almost no calcium sulphate is found in 
the furnished paper. The solubility is less when hard water is 
used, and it is decreased by the addition of alum. The quantities 
of crown filler used are generally 40% to 50% of the fiber furnish. 

This filler is particularly useful in high-grade papeteries, where 
a high white color or delicate tints are desired. As it is the most 
expensive of the fillers and has the lowest retention, its use is 
necessarily confined to the better grades of paper. When present, 
it interferes somewhat with the rosin sizing of the sheet, because, 
owing to its solubility, enough calcium sulphate is in the solution 
to react with the rosin size, precipitating a calcium resinate, or 
calcium soap, which has no sizing value. A similar effect on 
sizing is observed when very hard water is used. 

18. Pearl Filler. — Chemically, pearl filler is the same as crown 
filler, except that there is no water of crystaUization and only 
about 1 % of mechanical water. It is found in nature, as are talc 
and agalite, and has merely to be ground and sifted to prepare it 
for use. The alkalinity is about the same as talc, 1% to 2%, 
figured as CaCOs, and the grit is less. In color, it is not equal to 
crown filler, but it is far better than in any of the other fillers. It 
is less expensive than crown filler and its retention is greater. The 
chief reason for its greater retention is that of each 100 pounds of 
crown filler added to the beater, 33 pounds is water, while pearl filler 
is almost free from water. Pearl filler is used chiefly in medium- 
grade papeteries and writings, and it is added to the beater dry. 


19. Chalk. — In addition to those already described, a number 
of other fillers are used for very special papers. Chalk (the 
ground mineral), or calcium carbonate (precipitated for this 
purpose), is used in amounts as high as 30% in cigarette paper. 
Its use speeds up the burning of the paper, because, when the 
paper is heated, carbon dioxide gas is given off; this opens the 
pores of the paper and promotes combustion. Chalk also 
improves the color of the ash. 

20. Barytas. — Barytes, or barium sulphate, is used in photo- 
graphic papers on account of the special surface imparted to the 
sheet; it is quite expensive, and its retention is low because of 
its weight. It is also used in some special printing papers that 
must be very flat, it being held that the weight of the filler holds 

§4 LOADING 13 

the paper down. This filler is usually prepared by adding a 
soluble sulphate to a solution of barium chloride. 

21. Oxide of Iron and Wilkinite. — Oxide of iron is sometimes 
used to color leather board and box board, and to act as a filler 
at the same time. This material is said to give trouble, however, 
due to the pitting of press and calender rolls; this effect, is especially 
to be noted on the latter, if a water finish is being applied. 

Recently, work has been done on a very highly colloidal, clayey 
substance that is known to the trade as wilkinite, geologically 
called bentonite. This material appears to have the property 
of retarding the settling of clay suspensions. The indications 
are that it will also increase the retention of filler in paper. 

22. The Microscopic Appearance of Fillers. — In Figs. 3, 4, 5, 
and 6, are shown photomicrographs of four commonly used fillers. 
These were prepared by the Paper Section, Bureau of Standards 
(United States). They show the marked difference between the 
finely divided, colloidal clay and the highly crystalline crown 
filler; also, the similarity between talc and asbestine. A few of 
the needle-shaped crystals are visible, especially in the asbestine. 
The magnification in each case was 100 diameters. 


23. Per Cent of Retention. — By retention of filler is meant the 
pounds of filler found in the paper for each 100 pounds of filler 
added to the beater. To find the per cent retention, divide the 
weight of the filler in the paper by the weight of filler added to 
beater and multiply by 100; thus, 

per cent retention = — ^^t— — ^/,,r^ — r—^— X 100 
weight of nller m beater 

Instead of using the weights of filler, the percentage of filler by 
weight may be used, in which case, care must be taken in calcu- 
lating retention that the per cent filler in the beater and that in 
the finished paper are figured on the same basis, which should be 
the weight of bone-drj'' fiber. Proper corrections should be made 
for the moisture content of the original filler and of the filler as it 
occurs in the paper, for the ash content of the fiber furnish, etc. 
Some fillers contain water of constitution (part of the molecule), 
besides moisture held mechanically; all this water is lost in 
determining the ash content. The particular formula to be used 
in any given case should be picked out after considering the 


accuracy of the final result that is desired. This matter is 
treated at length in the Section on Paper Testing, Vol.V. The per 
cent retention of the filler, as determined by the amount and 
character of the ash, is used in calculating the amount of filler 
that must be added to the stock. Allowance must be made for 
the solubility of the filler in some cases. 

When waste paper from the mill is used, especially "broke" 
(spoiled paper), consideration must be giv^en to any filler that may 
be contained in it. It will be seen, too, that any filler contained 
in white water that may be used in the beater or on the machine, 
will affect the retention of the filler added ; this water may become 
saturated, so to speak, with filler. 

24. Conditions Afif acting Retention. — The retention of any 
given filler will vary widely, according to stock and machine con- 
ditions. Other things being equal, retention increases as the 
weight of the sheet, the slowness (hydration) of the stock, or as 
the length of the fiber increases. It decreases as the speed of the 
machine increases, and as the amount of suction on boxes and rolls 
increases. Retention is greater in a well-sized sheet than in a 
slack-sized sheet; with mechanical and sulphite pulps, it seems to 
decrease with the length of fiber. Other conditions being the same, 
but using different fillers, the retention increases as the size of the 
filler particles increases, and as the specific gravity or weight 
per cubic foot decreases. Retention decreases as the solubility 
and moisture content of the filler increases. Other conditions 
affecting retention are the amount of shake of the machine, 
and the quantity of fresh water or of white water used. The reten- 
tion is less than the normal by from 10% to 20%, if the amount of 
filler added is less than about 5% or greater than 30% of the 
weight of the fiber; this last does not apply to crown filler, which 
reaches its maximum retention with additions of 50% to 60%, nor 
to pearl filler. 

Unfortunately, little retention data for pearl filler are available. 
It seems, however, that the ratio of bone-dry calcium sulphate, 
with no water of crystallization retained, to bone-drj'- calcium 
sulphate added, is approximately the same for both crown and 
pearl fillers, when large amounts are used. Crown filler usually 
contains about 33 % of water whereas pearl filler contains almost 
none at all. If the retention is based on the actual pounds of filler 
added, irrespective of moisture content, the retention of pearl 
filler would be about half again as great as that of crown filler. 



25. Some Retention Data. — The following data are based on 
papers having a folio weight (standard substance number or 
weight per ream of 500 sheets, 17 inches X 22 inches) of about 20 
pounds, an addition of filler of 10% to 20%, and a machine speed 
of 100 to 200 ft. per min. The figures are average results; the 
papers were writings and envelopes, with a few book papers. The 
retention to be expected in book paper of medium weight is about 

Cos+in Cents per Lb. of Filler in Paper 
55 ? ^-^Q '°Q '-^Q ^°° ^-50 3.00 3.50 4.00 4.50 5.00 5.50 £.0 

25 30 35 40 
Per Cenf Reiained 

Fig. 7. 

10% lower than the figures obtained, which were: talc, 82%; 
agalite, 75%; clay, 70%. 

For crown filler, the following figures for the same sheet weight 
and range of machine speed are given. The papers were writings 
and papeteries.^ 

Per Cent Added 
(Pounds Per 100 Pounds of Pulp) 


Per Cent Retained 
(Based on Filler Added) 


1 Papers for fancy correspondence bo.xes, and the like. 


26. In Fig. 7, a curve is given of the retention of crown filler, 
showing how this varies with the amount added. Another 
curve is also given, which shows the variation in the cost per pound 
of filler in the paper with the amount added to the beater; the 
rapid increase in cost when small amounts are added is very 
evident, and is due to the large percentage lost. The cost of this 
filler dehvered to the mill was $1.08 per 100 pounds when this 
cost curve was drawn. 

27. Other conditions than those mentioned being constant, 
retention of filler will vary as follows: 

Retention Increases Retention Decreases 

As weight of sheet increases; As solubility of filler increases; 

As machine speed decreases; As amount added to beater 

As engine sizing changes from slack decreases below 5%; 

to good; As amount added to beater 

As slowness of stock increases; increases above 30% (except 

As length of fiber increases; crown filler). 
As size of filler particles increases; 
As specific gravity of filler decreases. 

28. When to Add the Filler. — The proper time for adding filler 
is generally thought to be as soon after "furnishing" as possible, 
and before the addition of size and alum, as the precipitation of 
size tends to fix the filler in the fiber. The usual practice is to 
add: first, filler; then, rosin; and, last, alum. 

Retention will be increased by the use of starch or sodium 
silicate; but it is doubtful whether the increase warrants the use 
of these materials for this cause alone. Some even advocate 
boiling filler and starch together. It has also been recommended 
to mix the clay with separately boiled starch, and then add 
rosin size to the mixture; after which the whole is added to the 
beater. Unfortunately, there is little actual data available. 
Clay, however, should be added, and it should be thoroughly 
mixed with the stock, before alum is added; otherwise, the acid 
of the alum will destroy the colloidal properties of the clay, 
thereby lowering retention, giving poorer finish, etc. 


(1) What substances may paper contain, other than fiber? 

(2) IIow is clay produced? How does it differ from talc? 

(3) What chemical difference is noted between crown filler and pearl filler? 

(4) How is clay usually added to the beater? (h) talc? 

(5) Would you expect any difference in the retention of crown filler in soft 
water and hard water? Explain your answer. 

§4 LOADING 17 


29. Sampling. — The sampling is done by opening 5% to 10%, 
preferably 10%, of the barrels or packages, as received from the 
car, and taking a small portion of each, making the weight of 
the total sample about 5 pounds. In case of a shipment in bulk, 
it is best to take the sample at frequent and regular intervals, 
as the shipment is being unloaded. From a car of clay, the filler 
most commonly shipped in bulk, the sample thus taken should 
weigh about 50 pounds, and should represent both the fine and 
coarse portions. The lumps should be broken up and the sample 
quartered down, until it will about fill a Mason jar; this is kept 
in an air-tight container until the analysis is to be performed. 

30. Preparation for Analysis. — The 5-pound sample is care- 
fully mixed, all large lumps are broken up, and the whole is 
quartered down to about 50 grams. The analyst will do well at 
this point to determine whether the filler is clay, talc, agalite, 
calcium sulphate, etc. A qualitative test may also be made for 

31. Moisture Content. — Mechanically combined moisture is 
determined on 2 grams of this sample by drying at 105°C. to a con- 
stant weight. The chemically combined moisture may be 
determined b}' placing this dried sample in a crucible and heating 
at the full heat of a Meker burner until a constant weight is 
secured; or by heating 2 grams of the original sample in the same 
manner, and then subtracting the mechanical (surface) moisture 
from the result. In the case of crown filler, the total moisture is 
determined by igniting a 2-gram sample over a Meker burner to 
constant weight; from this result, the chemically combined 
moisture may be calculated, the molecular formula for crown filler 
being CaS04-2H20. Subtracting this result from the original 2 
gi-ams taken for analysis, the mechanical moisture is obtained. 

32. Color. — Color is determined by comparison with a standard 
sample that has been selected for color. Small amounts of the 
sample to be compared and of the standard are pressed together 
on a black paper, with a poHshed steel spatula. Any difference 
in color can then be readily seen, and the sample is reported to be 
as good as standard, yellower, graj^er, or whatever difference 
is observed. 

33. Fineness. — Fineness ma^^ be determined microscopically, 
by elutriation or by the sieve method; but neither method is 




applicable to calcium sulphate or other appreciably soluble fillers, 
because of their solubility. Fineness is determined most simply 
microscopically. A very small amo\mt of filler is placed on a 
glass slide, with a small amount of water, and a cover glass is 
placed over the mixture. It is examined under low power of the 
microscope, comparing the sample with the standard, which has 
been treated in the same way. If a microscope is not available, 
200 grams of clay are mixed thoroughly with 1000 c.c. of water and 
strained through a 200-mesh, silk, bolting cloth, by use of a 
gentle stream of water. The material remaining on the screen 
is dried and weighed. This will give a fair estimate of the per 
cent of grit present. 

34. Elutriation Tests. — The elutriation test on a filler gives 
the per cent of grit or coarseness, but the method is very com- 

i Oyer f /on 



Fig. 8. 

plicated; for general purposes, microscopic analysis is sufficient. 
Binus' apparatus is very satisfactory for a careful elutriation 
test, and should be used when very careful analysis is necessary. 
The arrangement of this apparatus is shown in Fig. S. In making 
the test, 50 grams or 100 grams of bone-dry clay are weighed out, 
thoroughly slaked (preferably in some sort of tumbling device in 
which dupHcate results can be obtained), and strained through a 
100-mesh sieve into No. 1 receptacle. Water is then run in 

§4 LOADING 19 

at the rate of 2.8 c.c. per second, giving a rate of flow of 1.5, 
0.7, 0.18, 0.08, and 0.04 mm. per sec. in the various receptacles, 
which progressively increase in size, the smallest having, of 
course, the highest rate of flow. The flow should be continued 
until the water from the last receptacle is clear; then weigh the 
various residues. There will probably be little or none in the first 
two, and it will probably be found that the residue in the third 
receptacle is the best measure of the fineness of the sample. 
There are several other types of elutriating apparatus on the 
market, as those of Schone or Hilgard. This subject is very 
fully covered in Wiley's "Principles and Practice of Agricultural 
Analysis." The Schone apparatus gives very accurate results. 

35. The following method will give tests for comparing two 
fillers. A 10-gram sample of the filler is placed in a glass cjdinder, 
llf inches high and If inches in diameter, and which holds 400 c.c. 
The filler is thoroughly shaken up with a small amount of water, 
and the cylinder is filled to the top. From a large bottle, 58 inches 
above the bottom of this glass cyhnder, 2500 c.c. is allowed to 
pass through the cylinder from a glass tube, | inch in diameter, 
extending to the bottom of the cylinder. The residue is then 
filtered on a tared filter, dried, and weighed ; this gives the amount 
of grit or coarseness in the filler. Variation in the rate of flow of 
the water can be made to suit special conditions. Other things 
being equal, the greater the rate of flow the larger the particles 
carried out of the cylinder, and the smaller the apparent amount 
of grit in the sample. The amount of grit in any filler should be 
less than 1.5%. When a partially soluble filler is tested, the 
water used must be saturated with it, and the temperature must 
be kept constant. 

36. Sieve Test. — For the sieve test, which is not so reliable as 
the elutriation test, a set of standard sieves, from No. 100 to 
No. 325, inclusive, is recommended. These numbers have been 
given to a scientifically determined series and correspond approx- 
imately to the ordinary mesh. These should be small, and be 
light enough to permit the residue to be weighed on the sieve with- 
out transferring to tared filter paper. This method is as follows : 

Place the weighed sample of clay in a beaker and add distilled 
water. For a 50-gram sample, add 500 c.c. of water. Let stand 
for one-half hour, and then agitate thoroughly, but without 
grinding. Let stand for a few minutes, for the coarse material 


to settle in the bottom, and decant through the weighed sieve, 
which has been previously cleaned and dried in an oven at 105° to 
110°C. Decant a small portion slowly through the screen, and 
wash out with water. Gradually transfer the suspended 
material, finally leaving the coarse particles on the sieve. With 
proper manipulation, a large portion of the sample will pass 
through the sieve during the process of transference. If the 
contents are dumped on the sieve at one time, the coarse 
particles will clog the holes, which will cause the sieving operation 
to prove difficult, often impossible, unless the sediment is stirred 
with the hand. Such hand stirring or rubbing of the material 
through the sieve is strongly to be condemned ; it not only forces 
through the larger particles but it also permanently distorts the 
apparatus, so that the sieve is rendered worthless. Gently tap 
the sieve while washing under a stream of water. Toward the 
end, it will be found more efficient to place some water in a dish 
and to set the sieve in this; then, by a shaking motion, the sieve 
is washed from below. Such washing will remove the fine parti- 
cles much more quickly than by placing water on the sieve with 
the residue. By having a dish painted black, the thoroughness 
of washing a white pigment will be apparent. Finally, heat the 
sieve for 1 hour at 105° to 110°C., cool, and weigh. 

When properly used and cared for, sieves should be reliable 
for a number of years. No washers, shot, or other device for 
hastening the sieving process should ever be used. The follow- 
ing table gives the sizes of the wires and openings for standard 
sieves from No. 100 to No. 325. 

Sieve No. 


Opemivq in 


Wire Diameter, 























37. Alkalinity. — Alkaline fillers are likely to have an injurious 
effect on sizing and coloring, and where they must be used, 
proper precautions, such as in selecting colors, should be taken. 

The alkalinity due to carbonates and bicarbonates may be 
determined by any of the standard methods for the determination 

§4 LOADING 21 

of carbon dioxide CO2; that is, by treating with acid and weigh- 
ing the CO2 absorbed in KOH or soda lime. The advantage 
of the following method is that it does not involve the purchas- 
ing of elaborate apparatus, and it is more accurate and quick 
for routine work to determine small amounts volumetrically and 

The apparatus consists of two 1000-c.c. gas-washing bottles, 
filled with 20% solution of NaOH for the purpose of removing 
CO2 from the air. These flasks are connected to a 250-c.c. 
Erlenmeyer flask that is fitted with a rubber stopper, through 
which a dropping funnel is passed. The outlet of the Erlen- 
meyer flask is connected with a train, which consists of four 
50-c.c. Nessler tubes, fitted up as washing bottles. The tube 
nearest the Erlenmeyer flask remains empty, and serves as a 
trap for any vapors or solid particles that may be carried over 
mechanically from the generating flask. The next three tubes 
contain exactly 25 c.c. of N/2 NaOH solution. The last tube 
is connected to the suction, and a constant current of air, free 
from CO2, is drawn through the apparatus. In making the 
determination, 10 grams of filler is weighed into a mortar and tritu- 
rated with two 15-c.c. portions of water. The residue is then 
washed into the Erlenmeyer flask, the total volume of solution 
being about 50 c.c. The apparatus is connected up. The 
pinch cocks are opened on the connection between the Erlen- 
meyer flask and the wash bottles on the one side, and the first 
and second Nessler tubes on the other side. A current of air, 
free from CO2, is drawn through the apparatus at a moderate 
rate. During this time, the Erlenmeyer flask is shaken occa- 
sionally. In a dropping funnel 50 c.c. of a 10% alum solution 
is placed, the stop cock is opened, and the alum is allowed to run 
into the Erlenmeyer flask, care being taken that the alum does 
not run into the flask fast enough to force the filler emulsion 
backward into the wash bottles. A column of alum solution 
should be allowed to remain in the stem of the funnel as a seal. 
An hour after the alum solution is all added, the pinch cocks are 
closed and the suction shut off. The contents of the last three 
Nessler tubes are washed carefully into a flask, and are titrated 
with standard N/2 acid, using phenolphthalein as an indicator, 
until an end point is reached; then methyl orange is added, 

'Quantitative Analysis; Treadwell and Halls Quantitative Analysis and 
Mahin's Quantitative Analj'sis are suggested as reference works on labora- 
tory procedure and general analysis. 


and the titration is completed. A blank consisting of 25 c.c. 
of N/2 NaOH solution is titrated with N/2 acid in the same 
manner. Phenolphthalein titrates one-half the carbonates 
present and all of the hydrates present, and methyl orange 
titrates the other half of the carbonates. Calculate the alkalin- 
ity in terms of calcium carbonate, by multiplying the methyl 
orange titration by 2 and then by 0.02504. 

The alkalinity due to calcium carbonate is of chief importance 
in a paper filler, and should be kept under 5%. Excess alkahn- 
ity tends to kill rosin size, causes excess foam, and maj'- alter the 
shade of certain dye stuffs. 

38. Iron. — Take 2 grams of sample and dissolve in 10 c.c. CP* 
Cone. HCl. If there is any residue, fuse it with sodium carbon- 
ate, dissolve in concentrated hydrochloric acid, and add to the 
main portion of the solution. Wash dissolved filler into alOO-c.c- 
Nessler tube, and add a few drops of a N/10 KMnO* solution, 
to be sure that the iron is oxidized to a ferric condition. The 
color of the potassium permanganate KMn04 should persist 
for at least two minutes. Add 10c. c. of potassium sulpho- 
cyanide KCNS solution (2% solution), and make up to 100 c.c, 
mixing thoroughly. Compare immediately the resulting color 
with a standard that has been prepared at the same time, by 
adding a standard iron solution (1 c.c. = 0.00001 gram FeaOs) 
to another Nessler tube, which contains two or three drops of 
KMn04 solution, 10 c.c. of KCNS solution, and 85 c.c. of H2O, 
until the same color is produced in both tubes. The number of 
cubic centimeter of iron solution used multiplied by 5 gives the 
parts of Fe203 per milHon. Iron solution is best prepared by dis- 
solving 1 gram of pure ironwireinasmallamountofH2S04, oxidiz- 
ing this with N/10 KMn04, and making up to 1000 c.c. By diluting 
a httle of this solution 100 times, a solution containing 0.00001 gram 
Fe203 is obtained. The amount of iron in fillers used in paper- 
making should be kept very low, especially in a filler partially 
soluble in water, as crown filler, where the iron content should 
not exceed 0.005%. In fillers that are insoluble in water, the 
presence of iron is usually detected by the high yellow color 
that makes them unsatisfactory for paper making. 


(1) How should a sample of filler be taken and prepared for analysis? 

(2) Explain the testing of a filler for alkalinity. Why is this important? 


(PART 2) 
By Judson a. DeCew, B. A. Sc. 



39. Tub Sizing. — In the early days of its manufacture, when 
it was made by hand in small sheets, the method of rendering 
paper non-absorbent consisted entirely of surface sizing, which 
was effected by dipping the finished sheets into a solution of glue 
or gelatine (prepared from hides), after which the paper was 
air-dried. This process is known as tub sizing, and the size 
used is called animal size. Further details of this practice and 
the method of its application under modern conditions are 
given in the Section on Tub Sizing ond Finishing Operations, 
Vol. V. This practice continued until 1807, when rosin sizing 
was discovered by Maritz Illig of Erbach, Frankfort, Germany. 

40. Rosin Sizing. — Briefly stated, the process of rosin sizing 
consists in adding to the stock in the beater a sufficient quantity 
of a soap made by cooking rosin (which is a mixture of organic 
anhydrides) with a solution of caustic soda or soda ash. When 
this soap, which may or may not contain rosin in excess of the 
amount necessary to combine with the soda, is thoroughly mixed 
with the stock, alum (aluminum sulphate) is added, either in 
powdered form or in solution. The alum causes the rosin to be 
precipitated on the fibers in the stock, together with a certain 
amount of aluminum hydrate. When first formed, this precip- 
itate is gelatinous; and, when mixed with the paper stock, is 
spread over the individual fibers. When the stock is run on the 
§4 23 


machine and dried, this h3^drated or resinous material hardens, 
and forms a coating that is more or less water repellent, which 
completes the sizing operation. The degree to which the paper 
is made impervious to water depends on the amount of rosin and 
alum used, the phj-sical properties of these substances when the 
precipitate was first formed in the beater, the kind and quantities 
of fiber and loading, the manner of beating, temperature of 
machine dryers, etc. 



41. Sources of Rosin. — Rosin is the trade (or common) name 
of the substance otherwise known as colophony, which is the 
residue left in the still after the distillation of the turpentine and 
pine pitch. Pitch, or oleo resin is obtained from a large number 
of species of pine; but the chief commercial source is the longleaf 
and shortleaf pine of the Southern States. These trees are tapped 
by cutting the bark and allowing the resin to exude and flow 
into cups in the form of a thick liquid, which is collected and 
distilled. During distillation, the turpentine distills over and is 
collected separately; the residue in the still is roughly filtered, 
while molten, and forms the rosin of commerce. 

42. Grades of Rosin. — Rosin is graded into a large number of 
classes, according to the depth of color and the amount of impuri- 
ties it contains. The grades are designated by the letters of the 
alphabet, those bearing the first letters of the alphabet being the 
lowest in quality and the darkest in color. The highest grades 
are WG (window glass) and WW (water white). The grades 
most used for paper-maker's size are F and G. The reason for 
this is that, although the lower grades give good water resistance, 
they cannot generally be used on account of the color, while 
those lighter than G are not hard and dense enough to give the 
best sizing. These grades arc standard, and the rosin coming on 
the market in the Southern States is inspected and graded by 
Government Inspectors. 

Quotations are made in terms of a barrel of 280 pounds, but the 
rosin is marketed in casks that have a gross weight (the cask and 
its contents) of about 500 pounds. Consequentl}'^, when purchas- 


ing rosin for use in paper making, allowance must be made for 
waste in breaking up the containers. The weight of the staves is 
from 17% to 18% of the gross weight. The price of rosin fluctu- 
ates considerabl}^, depending on the demand in various parts of 
the world for rosin and also on the demand for the turpentine that 
is produced at the same time as the rosin, 

43. Characteristics and Uses of Rosin. — Chemically, rosin 
consists chiefly of the anhydride of abietic acid C44H62O4. For 
practical purposes, however, rosin may be considered as consisting 
of 90% to 97% of abietic acid C44H64O5, because the anhydride, 
when cooked with alkali, gives salts (or soaps) in exactly the same 
manner as abietic acid itself would do. One of the outstanding 
characteristics of soaps made from rosin is their ability to 
emulsify oils and like materials in water solutions. It is this 
property of rosin soap which makes possible the use of size 
solutions containing a quantity of rosin in excess of that required 
to combine with the soda. 

Other uses for this rosin are in the manufacture of soap, 
linoleum, and varnishes, as raw material for the production of 
rosin oil, and as a constituent for various plastic compositions. 

44. Extracted Rosin. — In addition to obtaining rosin direct 
from oleo resin, it may be obtained by extracting with solvents, 
such as naphtha, the resinous dead wood of the Southern pines. 
The rosin so obtained is called extracted rosin, and its compo- 
sition differs from that made from pitch. When used for sizing 
papers, it must be handled somewhat differently also. Extracted 
rosin is quite free from dirt and is uniform in character; but, on 
account of its dark color, it is generally classed as F rosin. 

About 14,5 pounds of soda ash is required to neutralize the resin 
acids in 100 pounds of extracted rosin; whereas, about 16 pounds 
of soda ash is required for 100 pDunds of gum rosin. 

Another class of recovered rosin is that obtained from soda 
liquors in the cooking of resinous woods by the soda process. 
This rosin is recovered in the form of soap, is dark in color, has 
different physical properties from ordinary rosin, and if used 
alone, is not an efficient sizing material. 

45. Soda Ash. — Soda ash, or sodium carbonate Na2C03, 
combines with rosin to form rosin soap. It comes on the market 
in two varieties, the light and the heavy, the light variety being 
the most convenient for the manufacture of size. Soda ash 


should contain 58% of Na20; if any other percentage is used, 
allowance should be made for the difference, since only the NaeO 
takes part in the reaction. In some cases, caustic soda NaOH 
is used in place of soda ash; it saponifies the rosin more rapidly, 
but it is more difficult to handle and is more expensive. 


46. Paper-Maker's Alum. — Alum is the now commonly used 
trade name for aluminum sulphate Al2(S04)3l8H20, which is 
frequently called paper-maker's alum. Properly speaking, the 
term alum should be confined to the double salt of aluminum 
sulphate and potassium sulphate Al2(SO)3K2S04-24H20, or a 
similar double salt, and the first alum used in paper making was 
this double salt, which can be obtained in a very high degree of 
purity. For this reason, it is still used by some paper makers, in 
spite of its greater cost; although this is probably entirelj^ 
unnecessary, since very pure aluminum sulphate containing 
16. 85% of AI2O3 can be obtained. A grade of aluminum sulphate 
is made which is practically free from iron and other impurities; 
but it is made by a special process, and it is expensive. The 
common grade of aluminum sulphate contains about 0.5% of 
iron, calculated as Fe203, and some alumina AI2O3 and silica Si02, 
none of which are sufficient in amount to be injurious to ordinary 
grades of paper. 

47. Iron-Free Alum. — For the best grades of paper, the 
percentage of iron in the alum should be as low as possible. Iron- 
free alum is made from pure alumina AI2O3 and sulphuric acid, 
whereas the common grades are made by dissolving bauxite in 
sulphuric acid and filtering the solution from the undissolved 
residues. The solution is then evaporated until it is reduced to a 
point where the moisture present would be that represented in 
the formula Al203(S04)3l8H20, after which, it soHdifies, and is 
then ground and packed for shipment. 

Owing to the two distinct methods used for making the iron- 
free and the commercial alum, there is a decisive difference in the 
composition of the two products. An alum, however, having as 
low as 0.2% of reduced iron sulphate should be good enough in 
color for the best papers. Often, more damage is done to the 
paper from iron specks that come from the beater bars than from 




the iron in the alum. Iron may show up as rust spots, or it may 
affect the color by reacting with the rosin or the dyestuff. 

48. Basic Alumina. — Paper-maker's alum generally contains 
an excess of alumina AI2O3 over the theoretical quantity to be 
accounted for in the formula Al203(S04).-il8H20. This excess 
of alumina is called basic alumina, although it is undoubtedly all 
combined with the SO3. 

An acid alum is one that contains free sulphuric acid. The 
jree acid is that in excess of the amount required by the alumina, 
iron, soda, etc. present. 

The brands of aluminum sulphate on the market are generally 
basic to the extent of 0.15% to 1 % of alumina; but, for some mill 
conditions, as, for instance, if hard water is used, an alum of 
more acid characteristics (up to 0.5% free acid) might be suitable. 

49. Uniformity of Commercial Alums. — In spite of the 
variation and the impurities in the bauxites from which it is 
made, the commercial aluminum sulphate is well standardized, 
and it is generally very uniform in character. Aluminum sulphate 
was once made largely from china clay, which is a silicate of 
alumina that contains about 37% of AI2O3; but china clay does not 
dissolve directly in sulphuric acid, unless it is previously calcined 
in a very exact manner. The silicious residue that is left when 
alum cake is made in this way from china clay is generally removed, 
as it has but little value for the paper maker, except as a filler. 

50. Analyses of Alum. — The following table gives characteristic 
analyses of alum (aluminum sulphate), compiled from several 
sources: the table is from Chemistry of Pulp and Paper Making, 
bv Sutermeister. 









Insoluble in water 

























12. 3-13. 0» 

Iron, FezOs 

0.1- 0.2 

Soda, Na20 




Sulphuric acid, SO3: 






0.4- 0.1 

' Column 8 gives average composition of alum cake from clay. 
* Soluble. 


51. Reaction of Alum and Rosin Size. — When a solution of 
soap, such as rosin size, is mixed with a solution of aluminum 
sulphate, the alumina combines with the rosin part of the soap, 
and the soda portion of the soap is left to combine with the sul- 
phuric acid from the alum solution, forming sodium sulphate. The 
combination of alumina and rosin is insoluble, and it immediately 
precipitates from the solution, coating anything with which it 
comes in contact. If," for instance, the mixing is done properly in 
the presence of pulp, all the individual fibers of the pulp are coated 
with this compound of alumina and rosin. 

In the early days of chemistry, it was thought that the com- 
bination of alumina with rosin formed an aluminum-rosin soap; 
but later advances in chemistry have created the belief that, in 
addition to the formation of this soap, the precipitated material 
may contain free rosin and free alumina, the whole forming a 
complex jelly, the characteristics of which are modified to a very 
great extent by the proportions of the reacting materials originally 
present. The exact reaction is still a matter of controversy. In 
any case, the result of the reaction is a combination or mixture of 
alumina and rosin that is precipitated, and, on drying, this 
furnishes the water-repellant properties to the paper. 

The amount of water resistance imparted to the paper depends 
not only on the manner of combination of these ingredients but 
also on their physical properties, which are influenced by the 
temperature, the state of dilution, and the rate of reaction of 
the various materials. These apparently simple reactions are 
really so complex, and are affected by so many physical condi- 
tions, as well as by various chemical impurities, that the more 
the subject is studied the more interesting and uncertain it 
becomes. The final result is also affected by the treatment in 
the machine room and the finishing room. 



52. Original Method of Saponifying. — The original method of 
saponifying rosin for use in sizing followed closely the general 
practice of soap manufacture. The rosin was boiled with a 
solution of soda ash, which contained somewhat more soda ash 
than was absolutely necessary to combine with all of the rosin. 


When fully boiled, the whole was left to stand until the saponified 
rosin settled out to the bottom and a weak solution of alkali 
remained on top; this latter was then skimmed off, leaving the 
rosin soap ready for use. 

This kind of size is still in use in many mills, and it is the most 
soluble form of size. It can be added in wax form, directly to a 
cold beater, and it is the safest kind of size to use, when there is 
no diluting equipment. 

53. Modem Method of Saponifying. — In later times, it has 
become more common practice to use a rosin size that is not 
completely saponified ; in other words, one that contains a certain 
amount of free rosin. The manufacture of this size ismuch 
simpler, and it is usually carried on as follows: 

A steel tank, opened at the top, but preferably with a hood 
over it, is fitted with steam coils covering the bottom. Into this 
tank is put a solution of soda ash, which contains from 8% to 
16% (by weight) of soda ash, figured on the basis of the amount 
of rosin to be cooked; the percentage may be varied, according 
to the character of the rosin and the finished size. The amount 
of water may vary from 50% to 100% of the amount of rosin. 
When this solution is heated by the steam coils (or by the live 
steam if perforated coils are used) to the boiling point, the rosin, 
broken up into small lumps, is shoveled in. It dissolves quite 
rapidly in the hot soda-ash solution, and gives up bubbles of 
carbon dioxide as the rosin combines with the soda. When 
all the rosin is in, cooking is continued for from 4 to 6 hours. 
The course of the reaction can be followed by watching the evolu- 
tion of this gas, which continues to come up as long as there is 
uncombined soda ash present. 

Another method of determining the completion of the cooking 
is to observe the way the cooked rosin flows from the end of a 
paddle that has been dipped in it. While being cooked, it runs 
off the paddle in long strings; but when the cooking is complete, 
it breaks off sharply. 

Still another method for testing the size is to take a pint of 
size, mix thoroughly with a quart of hot water, thin with cold 
water until pail is almost full and examine for lumps, grains, and 
sticky particles of free rosin. The cooking should be continued 
until the test shows that the size may be diluted as above into 
a homogeneous milk, free from these indications of raw or poorly 
emulsified rosin. 




54. To Make Soap Containing a Definite Per Cent of Free 
Rosin. — The amount of soda ash used in cooking the rosin 
determines the percentage of free rosin in the finished size. As 
an approximate guide to the manufacture of size containing 
various percentages of free rosin, the following table, which 
shows the results of the action of various percentages of soda ash 
on the rosin, may be used. The table is calculated for a rosin 
having an acid value that will neutralize 16% its weight of sodium 
carbonate, leaving 8.8% of rosin that will not saponify in aqueous 

Saponification Table 



Rosin soap 

Free rosin 

Total size 































This table can be corrected for any rosin that has a different 
saponifying value; and since it is based on 100 pounds of rosin, 
the values in the several columns maj^ be considered as per cents 
instead of pounds, if so desired. The first four rows give formulas 
for making the rosin sizes in general use. The first, in which 16 % 
of soda ash is used, will make a so-called neutral size, which is 
easily dissolved; perhaps 20% to 25% of the mills in America 
still use this size and believe that it suits their conditions. A 
size cooked with 14% soda ash, having a total free rosin content 
of 20%, is a tj'pe of size quite commonly used; it is called mill 
size. The size cooked with 12% soda ash and holding about 30% 
of free rosin, is another type quite largely sold to mills having 
diluting systems. The size cooked with 10% of soda ash, contain- 
ing 43% of free rosin, is a type used only in those mills having 
special systems for handling a high free-rosin size. The cooking 
may be done in the paper mill, or the mill may buy the prepared 

55. Tanks for Cooking Rosin. — The size of the tank for cooking 
rosin should be at least double that necessary to contain the 




finished size, because of the froth that rises up during cooking; 
hence, the tank will overflow, unless it has sufficient capacity. 
In the open size boiler, Fig. 9, provision is made for the froth to 
flow back into the tank A through the by-pass B; C is a, steam 

Fig. 9. 

Fig. 10. 

In the modern American size cooker (patented) shown in Fig. 
10, a truncated conical surface B is suspended over the coils C 
The circulating action through the cone is so rapid that the size 
can be cooked violently and rapidly without boiling over. 

56. There is another method of cooking which has been 
advocated in the past and is still sometimes used. The size is 
cooked in a closed tank, with indirect steam under pressure, 
either with or without an agitator. In Fig. 11, ^ is a pressure 



size cooker, equipped with an agitator B, steam coil C, water 

inlet H, manhole M, and size outlet 
.V. Instead of using coils, the lower 
half of a cooker is sometimes enclosed 
in a steam jacket. 

When cooking in this manner, the 
temperature can be brought to a 
point considerably higher than when 
cooking in an open tank; but the 
circulation, and the consequent uni- 
formity of the finished size, is liable 
to be faulty, unless a special agitator 
is used. Under suitable conditions, 
the size can be cooked under pressure 
in less than 2 hours; in the open 
tank, from 3 to 6 hours are required. 
In former times, it was the practice 
to use an open tank, with direct 
steam, and this required boiling from 
Fig. 11. 6 to 8 hours. 


(1) State briefly the principles underlying the use of rosin sizing. 

(2) (a) How is rosin obtained and graded? (b) What grades are used for 

(3) WTiat is meant by the term saponified? 

(4) Give the chemical name, the molecular formula, and the character- 
istics of soda ash. 

(5) (a) Give the common name for aluminum sulphate. (6) When is this 
substance acid? (c) when is it basic? 

(6) Explain the process of cooking a batch of rosin size. 

(7) How much soda ash should be used for 100 lb. of rosin to make 
a size having about 30% free rosin? 

(8) By what signs can it be determined when the cooking of size is 


57. Reason for Diluting Size. — One of the critical operations 
in connection with the sizing process is that of diluting the thick 
size, or wax. In the case of neutral size, this operation is not so 
important, since the size is then soluble in water to such an extent 


that it is generally added thick to the beaters, without previous 
dilution. The case is different, however, when size containing 
free rosin is being used. The object then is so to dilute the thick 
size as to make an emulsion of such a character that the free 
rosin is as reactive as possible. If this be not done, the separated 
rosin can produce lots of trouble on the paper machine. When 
the dilution is so carried out that the rosin inj^the emulsion formed 
is practically entirely invisible, it is then in the most reactive 
state. An emulsion in this condition contains the rosin in such 
fine particles that the whole forms what is known as a colloidal^ 
solution. When alum is added to such a solution, all the rosin is 
precipitated as though a neutral size were used; except that the 
precipitate formed contains a larger proportion of rosin and less 
soda, which gives, generally, a more water-repellant coating to 
the fibers. If the free rosin is not invisible in the diluted solution, 
but appears very white and milky, the free rosin is in suspension, 
and it is not in a chemically reactive state. These rosin particles 
precipitate when the neutral soap in the solution is coagulated 
by alum, but the precipitate consists of small particles of rosin 
imbedded in the rosin-alumina complex. The sizing qualities 
of this mixture will vary with the coarseness and the amount of 
the rosin particles. The best sizing result can be obtained with 
the more chemicallj'^ active emulsions, when other conditions 
are properly adjusted. 

58. Free-Rosin vs. Neutral-Rosin Sizing. — It maj^ here be 

remarked that there has raged, for some j^ears past, a very 

sharp controversy as to the merits of free-rosin sizing as against 

neutral-rosin sizing; and manj^ arguments, more or less correct, 

have been advanced in favor of one or the other. The advocates 

of the neutral size claim that the sizing is due to a resinate of 

alumina; those advocating free-rosin size claim that the sizing 

is due to the free rosin, and that the resinate of alumina has no 

effect. From the consideration of the physical chemistry of 

colloidal gels, it appears that the coating which furnishes the 

sizing qualities is a complex mixture, which consists of rosin, 

resinate of alumina, and alumina, and that no single one of these 

can be considered as being alone responsible for the sizing result. 

By both theory and practice, it is found that the characteristics 

of this gel, or coating, can be altered considerably by varying 

^ A colloidal solution is jelly like, in that the particles are held in suspension 
in solution, and do not separate from the liquid in which they are suspended. 


the conditions under which it is formed, and also by varying the 
amount and character of the free rosin in the size emulsion. It 
is only when these factors are adjusted to the mill conditions 
that the most efficient results can be obtained. 

It cannot be said, however, that solutions of size containing 
free rosin are, on that account only, more efficient than neutral 
sizes; but it can be affirmed that when the free rosin is in a 
reactive state and properly utilized, the free rosin size can be 
made to give more efficient results than the neutral size. Bear- 
ing this in mind, therefore, the methods used in diluting sizes 
containing free rosin, which is the kind of size used in most 
mills at the present time, will now be discussed. 

59. Methods of Diluting Size. — A size containing approxi- 
mately 20% of free rosin can be diluted to make a fairly stable 
emulsion in moderately warm water; in man}^ cases, a size of this 
constitution is added directly to the beater. It is unsafe to 
attempt to dilute a size containing more than 20% free rosin 
by adding it directly to the beater; for, if conditions are not 
just right, some of the particles may adhere to one another and 
form particles of rosin sufficiently large to show up as rosin spots 
in the finished paper. 

The proper method of using higher free rosin size is to dilute it 
to an emulsion containing approximately 2% of rosin, and then 
add this emulsion to the beater. This dilution is generally 
accomplished by adding thick size to hot water, with violent 
agitation. This may be effected by blowing the size into a 
tank of hot water in a fine stream jet, or by adding it in small 
quantities and stirring violently at the same time. When first 
made, such an emulsion is of fairly good character, provided the 
agitation has been sufficiently violent and the size has not been 
added too quickly. Unfortunately, however, an emulsion of this 
character, when hot, tends to destroy itself as an emulsion, owing 
to the fact that the rosin particles agglomerate, and the emulsion 
gradually becomes more and more milky. If kept hot for a 
sufficient length of time, the particles will become so large as to 
settle from the emulsion, leaving the remainder of less value. 
By chilling the partially diluted size with cold water, this 
difficulty might be avoided; but it is hard to do this without 
causing further decomposition. 

By using a S3'stem of graduated dilution, a better emulsion 
can be obtained. This is accompfished by first diluting the size 


to a consistency of about 25% solids, and then adding, at a 
boiling temperature, a certain number of parts of water, the 
amount of which will vary in accordance with the free rosin 
content of the size. After the size has been diluted to this stage, 
and it will rapidly disperse in cold water. 

Suggestions have been made at various times that other 
substances might be added to the hot water, or to the size, which 
would act in such a manner as to protect the size particles from 
this tendency to agglomerate into larger ones. Substances 
having this property are known as protective colloids, and they 
include many materials of a gelatinous character. The addition 
of these substances has a very definite efTect; but the advantage 
to be derived depends upon the material used and upon the 
conditions under which the sizing is done. 

The disadvantage from the use of these materials is the fact that 
a tendency to froth is often produced, and more coloring matter 
may be introduced, which will effect the brightness of the paper 

60. Diluting System. — There are two well-standardized sys- 
tems for diluting a thick size. In one of these, the process 
consists of mixing the thick hot size with a small quantity of 
hot water, at a definite temperature, within an injector, and 
violently agitating the size and water, at the moment they mix, 
by means of steam pressure, which is applied to the hot water 
from a jet of steam. An instantaneous solution is accomplished 
in this way; and its physical character is preserved by using the 
same pressure of steam to blow the mixture into a large amount 
of cold water, which immediately stabilizes the emulsion. An 
emulsion that may contain as much as 50% free rosin can be 
made into what is practically a purely colloidal solution having 
the maximum sensitiveness to reagents, such as alum. Fig. 12 
shows the arrangement of this system, the lettered parts being 
as follows : 

A and B are barrels of rosin; C is a cooking tank, heated by 
steam pipe D; £ is a measuring tank; F is the heating coil; F is 
the emulsion tank; H is a device for mixing heated rosin soap from 
E with water from Y (through pipe L) and steam from T, which 
injects the mixture into Y; ^V is a connection for supplying water 
during emulsification; and Tt: is a storage tank. 

61. The other diluting system, illustrated in Fig. 13, consists, 
essentially, of a steam injector, so designed that the hot size 




flows from heated measuring tank A into the injector B; from B, 
it is forced by means of a steam jet from steam pipe C into hot 

Fig. 12. 

water in D, and some cold water is finally added through E. 
F is a, perforated steam coil, which heats the contents of D and 
assist in mixing. Details of the injector are shown at (6). 

Fig. 13. 

62. A later development of this method consists of a pressure 
tank holding hot size, from which it is forced under pressure 
directly into a tank containing hot water. This process has 


some advantages over the steam injector; but here, also, 
there is not much control over the operation. It is being 
operated generally with a size carrying from 25% to 30% 
free rosin. 

Two other methods are still used occasionally: One is to drop 
the hot size directly from the cooker into a tank containing 
twice as much hot water, which is stirred by an agitator; when 
completely mixed, cold water is run in and mixed until the 
correct volume is obtained. The other is to feed the hot size 
along with hot water into a fan pump, from which it is dis- 
charged into a diluting tank. Either of these methods may be 
used with a size carrying 25% or less of free rosin. 

63. Handling Diluted Size. — As it is seldom possible to use the 
size immediately after it is diluted, it becomes necessary to store 
it until the stock is ready to receive it. Most mills prefer to 
keep a fairly large supply of diluted size emulsion on hand; this 
is generally kept in large tanks, the capacity of which depends 
on the amount being used daily in the plant. About one day's 
supply is the amount usually kept for this purpose, though the 
amount thus stored may be varied, being greater or less, to suit 
the working conditions of the mill. A well-made emulsion will 
keep quite well at ordinary temperatures for a considerable 

64. Effect of Hard Water. — The water used in diluting the 
size should be as soft and pure as possible. As a general rule, 
however, it is impossible to obtain absolutely pure water; and a 
certain degree of deterioration in the emulsion must be expected, 
on account of the salts dissolved in the water. These salts act 
in a manner somewhat similar to alum, and they precipitate a 
portion of the size. The salts of lime and magnesia form 
insoluble soaps (resinates), which produce a thick scum on the 
emulsion tank. This is merely a verification of what happens 
when the size is discharged into a beater full of hard water; 
it explains why it is necessary for a mill using hard water 
to increase the amount of alum in order to get the lime out of 
the way. 

Salts such as sodium chloride, sodium sulphate, and other 
salts of the monovalent elements, are almost equally detrimental; 
if they are sufficiently concentrated, they will tend to break up 
the emulsion and slowly coagulate it. They displace the rosin 


soap in the solution, because they are themselves more 
water soluble. 

65. Furnishing the Beater. — In mills using diluted size as 
above described, it is the general practice to pump the diluted 
size from the storage tanks to the beaters. For measuring the 
size at the beater, a tank should be placed either over the beater 
or somewhere near and hand}' to it; and it should be equipped 
with a gauge that is graduated to show the amount of rosin per 
inch of depth of the measuring tank. The graduation of this 
gauge may be simply in inches, or in pounds of rosin, or in 
terms of some unit to which the mill has become accustomed, 
such as a pail or a dipper. Some prepared rosins are added 
directly to the beater, and directions call, usually, for so many 

All these methods are in use; but it would seem that the most 
logical procedure would be so to graduate the measuring tank 
that the number of pounds of rosin for a given volume could be 
stated definitely. It is frequently possible to use one measuring 
tank for a pair of beaters, if they are close together. These 
tanks should have a wash-out connection for cleaning. 

66. Adding Alum. — While alum may be, and frequently is, 
added to the beater in ground form, it is considered better 
practice to dissolve the alum first and add it in the form of a 
concentrated solution. Alum solutions are very corrosive to 
iron; they should not be handled in anything but wooden pails, 
and should be stored or contained only in wooden or concrete 
tanks having bronze fittings. Concrete tanks for holding alum 
must be specially prepared and treated, to resist the corrosive 
action of this acid salt. 

The common form of an alum-diluting system consists of a 
wooden tank, with an agitator; this is worked on the batch 
(intermittent) system, and is used to dissolve ground alum. The 
cheapest method is to buy the alum in large cakes, and to keep a 
large tank (without agitator) filled with these cakes. The 
tank is also kept filled with water; and a fairly strong solution 
can be taken from the bottom, the density of which will vary 
with the temperature of the water and the length of time of 
contact. Some mills use two tanks equipped alike, one being 
used as a storage tank while alum is being dissolved in the other. 
The solution is kept uniform. 



67. Complexity of Reactions. — The problem of sizing is 
extremely complex. Different reactions take place between the 
rosin and the aluminum sulphate, which depend on the amount 
by which the aluminum sulphate exceeds the amount actually 
needed to react with the rosin soap. When no other factors 
intervene, a definite ratio may be determined for a size having a 
fixed percentage of soap and for certain mixing conditions. The 
whole reaction is made uncertain by the presence of other 
reactive salts, which are either in the water or in the stock; and 
these salts are of such a complex character that no definite 
formulas can be given that will apply to every case. 

As a general rule, the size goes into the beater before the alum ; 
but there are cases where there are so many injurious reactions 
lying in wait for the size that it suffers less injurj^ by going in 
last. Where hard water is used, it may be advisable first to add 
enough alum to take care of the hardness. 

68. Amount of Alum Required. — A general idea of how the 
size and alum react on each other can be obtained by assuming 
that no impurities are in the paper stock or in the water that 
contains it. Also, that the size and alum have both been 
properh- diluted, and that soft water is used in furnishing the 
beater, which is not heated. Under these conditions, it may be 
stated that a size containing from 35% to 45% of free rosin 
would require about 15 pounds of alum for every 10 pounds of 

Under similar conditions, a size having from 20% to 25% of 
free rosin should require about 20 pounds of alum for every 10 
pounds of rosin used; and a size that is fully saponified and 
alkaUne might require 30 pounds of alum for every 10 pounds of 
rosin used, to produce proper characteristics in the rosin precipi- 
tate and in the fibers. 

These ratios have no basis in theory, because, theoretically, it 
ought not to require over 4 pounds of alum for every 10 pounds 
of size; but, in actual practice, the proper combinations are not 
effected unless the alum is used in large excess; and this excess 
must be greater the more there is of rosin in the form of soap. 
The figures given may be used as a guide only. The right 
proportions of alum and size must be determined empirically 
for each mill; and the proportions will vary with the character 
of the stock and water and the methods of reclaiming back water. 




Difficulty may be experienced in sizing if steam is blown into 
the beater, as is sometimes done to "free" the stock, or if the 
stock becomes heated through beating action. 

Per Cen+ Alum 
I 2 3 4- 5 & 7 


05 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.S 5.0 
Per Cent Ro&in 



,.0 1.5 2.0 2.5 3.0 
Per Ceni- Alum 







H • 


— ■ 















0.5 1.0 1.5 2.0 2.5 3.0 
Per Ceni Alum 



05 1.0 1.5 2.0 2.5 
Per Cent Alum 


Fig. 14. 

69. Variation in Water Resistance.— The amount of water 
resistance that can be obtained in paper by the use of rosin size, 
depends upon the kind of size, the method of using it, the amount 


and kind of alum used, the character of the pulp, the amount 
of and temperature of beating, the formation of the sheet on the 
wire, the methods of extracting the water, and the manner of 
drying and calendering. 

It was stated in the Section on Properties of Pulpwood, Vol. Ill, 
that resins change on exposure to sun and air. This accounts 
for the fact that paper that has been exposed to sunlight becomes 
gradually less water resistant. 

What can be accomplished under good water and mill condi- 
tions, using a 40% free rosin size, properly diluted, is shown in 
curve No. 1, Fig. 14, which was presented by Paul Bray to the 
Technical Association' of the Pulp and Paper Industry at New 
York, Feb. 6, 1918. The curve shows that, under good condi- 
tions, the maximum sizing effect is obtained with 4% of rosin. 
He also determined the sizing results when using a constant 
amount of rosin and varying the alum. Beginning with 0.5% 
of rosin on the w^eight of paper stock, he obtained curve No. 2 
and other curves, Nos. 3 to 7, for each additional ^% until 3% 
of rosin was reached. Thus, for curve 2, the rosin was constant 
at 1%; for curve 3, the rosin was constant at 1.5%; etc. The 
ordinates (vertical measurements) in each case give the number 
of seconds require for a standard ink, at constant temperature, 
to penetrate paper floated on it. 

In another mill using the same kind of size and alum, but 
having different water and stock conditions, the curves showing 
the sizing results would be different under the several alum 
ratios. If a size were used containing no free rosin whatever, 
or if the size were decomposed on diluting, a still different curve 
would be shown, and the maximum result would be lower. 
Sutermeister points out (Chemistry of Pulp and Paper Making) 
that loading very materially reduces the sizing effect. Some 
fillers affect it more than others. 

70. Other Substances Added to Produce Special Effects. — 

There is no real substitute for rosin in sizing paper, but there are 
a number of materials that can be used with it to produce special 
effects. One of these is sodium silicate, "water glass," which, 
when precipitated with aluminum sulphate, gives a mixture of 
silica and alumina, which has a hardening effect on the paper. 

71. Sodium Silicate Na^SiOs. — Sodium silicate is one of the 
most attractive and, at the same time, one of the most difficult 


materials to use as a sizing ingredient. The properties of the 
siHcate are so different from those of rosin that it cannot be 
considered in any way as a rosin substitute; but it can be used 
to alter the characteristics of the paper and to modify the effect 
of the rosin sizing. Manj^ users of sodium silicate have had 
unsatisfactory results, either owing to the method of using it or 
because the properties obtained from it were not suited to the 
kind of paper treated. 

New methods of using sodium silicate that will extend its 
sphere of usefulness may yet be developed. It gives hardness 
and stiffness to the paper; and it is largely used by those paper 
manufacturers who are not able to get sufficient snap in their 
papers by other means. On some classes of paper, it will increase 
the Mullen test, but it will also reduce the folding qualities. 

72. Synthetic Resins. — During the World War, coumarone 
resins were used in Germany. They could not be saponified in 
the usual way, but were emulsified by means of rosin soap or 
glue. The production of a good synthetic resin has been the 
subject of much chemical research. 

73. Casein. — Casein is sometimes used in a beater for a special 
purpose, such as keeping down fuzz, or for increasing elasticity. 
It is dissolved by treating with an alkali, and it is precipitated 
by alum or other acid in a manner similar to rosin. Casein is 
relatively expensive, and it is likely to give the paper an 
unpleasant odor, unless used with great care. 

74. Starch. — Starch is used in sizing paper, both in engine 
and in tub sizing. As an engine size, it may be used alone or 
with sodium silicate. For tub sizing, a modified, or thin-boiling, 
starch is generally used. 

Starch does not make paper water resistant; but it imparts a 
certain slickness to the paper on calendering, increases the 
strength, imparts snap and rattle, and reduces fuzz on certain 
kinds of stock. 

When used in the beater, the starch may first be swollen and 
gelatinized by boiling; or the raw starch may be added directly 
to the beater, which should be done early enough in the process 
to get thorough mixing. The gelatinization of the raw starch, 
which makes it effective, is partly accomplished by the heat of 
the paper dryers. 



75. Color. — It is well recognized that rosin will give a yellow- 
ish tint to paper, and this must be offset as much as possible by 
the aid of blue coloring matter. The color effect of rosin becomes 
noticeable when over 1% of rosin is used. Inasmuch as the 
higher grades of rosin are not the best for sizing, it is important, 
in order to obtain the whitest color in the paper, that the sizing 
should be well done, using onl}'- the smallest quantity of rosin 

76. Strength. — The binding power of rosin size in the paper 
fibers is greater than the natural adhesion of groundwood or 
waste-paper fibers to one another, but is less than that between 
sulphite, sulphate, or rag fibers. In the manufacture of strong 
paper, the sizing problem is quite important, because low sizing 
efficiency means an excess of rosin to get the sizing standard 
required; and this, in turn, may reduce the strength of the paper 

77. Finish and Retention. — The finish of the paper often 
depends on the amount of filling material, in the form of fine 
fibers and mineral fillers, that is retained in the sheet as the water 
is drawn from it in during its formation on the wire. Since it is 
harder to polish a rough surface than to polish a smooth one, the 
fine material used to fill the voids between the larger fibers 
should be held evenly on both surfaces of the paper. When the 
sizing is of poor quality, more of the filling material is lost through 
the wire, and the paper is not only lighter in weight than it ought 
to be, but the wire side of the paper is rough, and it will generally 
show feathering action when written on with ink. 

78. Hardness. — The hardness of the paper surface depends 
partly upon the paper stock and the treatment in the beater; 
but when these factors are constant, the degree of hardness or 
softness of the paper can be varied by the kind and quality of 
sizing materials used. A good quality of high free-rosin size will 
produce a snap and hardness in the paper that cannot be obtained 
b}' the use of a neutral or low free-rosin size. 

The use of glue in the size will also increase the hardness, but it 
is a more costlj^ agent for this purpose. Glue is generally used 
for tub, or top, sizing, as explained in the Section on Tub Sizing 
and Finishing Operations. When the paper stock is to be tub 


sized or coated it must not be so well sized with rosin that the 
glue will not penetrate the paper, or the coating fail to adhere. 

79. Rosin Spots. — If suspended free rosin is in a sufficiently 
soft or molten condition when added to the paper stock, it will 
adhere either to the paper fibers or to the wires or presses, and 
it will gather other particles of rosin until masses of rosin are 
formed. These masses may cause translucent spots in the 
paper, or they may retard the operation of the machine. These 
troubles always occur when improper methods are used in 
dissolving or diluting a high free-rosin size. 

There are other rosin spots that may come from the natural 
resins and waxes of the wood; they ma}^ arise from an unbleached 
sulphite fiber, or from mechanical pulp made from a green, 
semi-resinous wood. The pulp pitch is a softer material than 
colophony rosin, and when it causes machine troubles, it can be 
readily recognized. 

80. Froth Spots. — When the paper stock has a tendency to 
froth, as a result of the kind of size used or of impurities in the 
water or pulp, and when, in treating the stock, there is a con- 
siderable amount of agitation, there is then likely to be an 
accumulation of froth on the screens and at the slices on the 
machine. This froth carries in the bubble film a certain amount 
of pulp, which is liberated when the foam is broken down by 
showers. The pulp will be sticky and resinous, and if it gets on 
the machine wire, it will leave a dirty splotch on the top surface 
of the paper. 

Froth can be prevented from foaming by lack of agitation, 
or it can be reduced by altering the surface tension conditions 
in the rosin size; a little kerosene is sometimes added to the 
stock for this purpose, but it is injurious to the sizing. A light 
froth that does not carry many pulp fibers will cause very little 


(1) Describe one method of diluting the size for use in the beater. 

(2) How and when should size and alum be added to the beater? 

(3) What determines the proportions of size and alum required? 

(4) What is the effect on sizing of (a) loading? (6) temperature of the 

(5) What are some of the troubles that may arise from sizing? Suggest 
a remedy for each. 



81. Newsprint. — This grade of paper uses the least amount of 
size, it being the general practice at the present time to leave 
out the size altogether. Newsprint is sometimes sized, however, 
especially in the case of paper produced for export, because it 
assists in giving the paper the best finish and printing qualities 
for certain kinds of work. 

One way to improve the finish and printing qualities for the 
best grades of newsprint is to make use of the beneficial properties 
of clay; but the use of clay is considered detrimental to speed on 
fast-running American paper machines. In order to get a 
reasonable retention of clay, it is necessary to use size. The 
highest grade of foreign newsprint may contain from 10% to 
20% of clay; under American conditions, 1% to 5% would be 
more usual, and this would apply to special grades, as half-tone, 
rather than to standard newsprint. 

The modern tendency is to make newsprint at a great speed, 
and to mix the stock in great tanks or chests, without beating 
or sizing. If any sizing effect is required to be obtained under 
these manufacturing conditions, very dilute solutions should be 
used, and they should be carefully prepared. Hanging, or 
wall paper, is generally classed with newsprint. It is not a 
difficult paper to size. 

82. Book Papers. — The engine sizing of book papers is depend- 
ent to a considerable extent upon the amount and kind of loading 
used. Proper sizing standards are very important; but the chief 
characteristic required in this class of paper is printing quality, 
which is indirectly affected by the amount of rosin sizing. A 
large amount of book paper has no sizing, but the average 
furnish would be about 1 % of rosin. 

It is economical to use rosin in all well-loaded papers, because of 
the increased retention of filler that can be obtained. This 
feature is probably more important than the sizing effect, since 
printing ink contains oil and does not require water resistance in 
the paper. 

83. Coated Papers. — Coated papers or papers to be pasted 
require that the degree of water resistance be not so great as to 
prevent some penetration by the water in the coating mixture; 
this is necessary to cause proper adhesion of the coating to the 


84. Bond and Writing Papers. — These papers are made from 
either sulphite or cotton fibers, or are from mixtures of both. 
They contain ver\' httle loacUng, and the results from engine 
sizing depend largely upon the chemical and physical properties 
of both the cellulose and the rosin. The problem of sizing these 
papers is more complicated than with any other grades. The 
stock is occasionally injured in bleaching. The amount of 
hydration is important, and this class of paper seems more 
sensitive to machine conditions. The problem of sizing is here 
sometimes complicated by considerations of coloring. 

85. Wrapping Papers. — There are three main classes of wrap- 
ping paper: kraft, or sulphate-fiber, papers; dry-finish sulphite- 
fiber papers; water-finish sulphite-fiber papers. In addition, 
there are real manila papers made from rope, which are very 
strong, and bogus manila papers made chiefly from ground wood, 
which are very weak. 

The kraft wrapping papers and the groundwood papers are 
easy to size, and they respond uniforml}^ to well-prepared free 
rosin solutions. Kraft paper is sized with from 0.5% to 2% 
rosin. The lowest amount of rosin is used in twisting paper, and 
the highest amount is used in tape papers. 

86. The dry-finish sulphite papers are usuall}^ more difficult to 
size, owing to variations in the character of the pulp, which does 
not always respond to sizing reactions. 

In water-finish sulphite wrapping papers, the sizing is practi- 
cally destroyed on the calenders. It must be well sized, however, 
when it leaves the dryers, or it will break on the calenders. The 
water penetration test of this class of paper will be 5 to 15 minutes, 
as it comes off the dryers, and 20 to 100 seconds, as it leaves the 
calender rolls. 

An excess of rosin is injurious to the strength of the fiber. The 
best product for these papers is made with hard sulphite and hard 

87. Wallboard. — Wallboard is exposed to conditions where it 
is desirable to have the least amount of expansion and contraction. 
The rate at which moisture may be absorbed by wallboard can 
be retarded })y rosin sizing, and the total amount of water 
absorbed can be restricted by the same means. 

Although surface coatings are often applied to pasted board to 
prevent expansion and contraction, it has also been proved to be 


desirable to have the soKd board sized hard enough to prevent the 
absorption of the pasting fluid. 

88. Testboard. — This product is used for making containers of 
various kinds; it is a kraft-Hned board, of which the hner is hard 
sized. Special difficulty is found in sizing this board because it is 
generally given a water finish, which is always injurious to rosin 

The paper maker must maintain a delicate balance between the 
amount of finish and the amount of rosin required, since the water 
resistance will vary inversely with the amount of pressure 
applied in the water finish. 

89. Rope and Grease -Proof Papers. — Rope stock is very hard 
material to size, because, probably, of the method of boiling the 
stock, the excessive beating, and the calendering conditions. 

Grease-proof papers are always poorly sized, owing to the 
calendering methods used for producing the translucency. 



(1) (a) Name five substances commonly used as loading for 
paper. (6) State which are natural products and which are 
manufactured products. 

(2) What are the usual impurities in clay, and why are they 

(3) (a) Explain the purpose of adding a filler to paper. (6) 
How much filler is generally used? 

(4) (a) What is meant by retention ? (6) What factors increase 

(5) How may the fineness of a filler be determined? 

(6) How is the amount of iron in a filler estimated? 

(7) Mention two important differences between engine sizing 
and tub sizing of paper. 

(8) (a) What is rosin, chemically? (b) Why is carbon dioxide 
given off when rosin is saponified with soda ash? 

(9) Why is the amount of iron in aluminum sulphate important ? 

(10) What happens when rosin size is mixed with a solution of 
aluminum sulphate in the presence of paper pulp? 

(11) What effect does the amount of soda ash used to make 
size have on the amount of alum required in the beater? 

(12) What effect does hard water have on rosin size? 

(13) Why is paper sized, and how is the effectiveness of sizing 

(14) Name two substances that may be added to the beater 
for special effects, and tell what they do to the paper. 

(15) What effect has sizing on color, strength, finish, and hard- 
ness of paper? 

(16) State the sizing requirements of five kinds of paper. 

§4 49 




Authorship: This Section was prepared by the Dyestuff Coininittee of 
the Technical Association of the Pulp and Paper Industry — Charles G. 
Bright, Ross Campbell, C. C. Heritage, Kenneth T. King, Clarke Marion, 
and Carl Schneider, in collaboration with Dr. Otto Kress. 

1. Scope and Purpose of this Section. — The pleasing appear- 
ance required of the finished paper depends very largely upon the 
proper manipulation of the coloring processes. The importance 
of this branch of paper manufacture is realized when it is con- 
sidered that fully 98 per cent of the tonnage of paper produced is 
colored in some form, ranging from the tinting of all types of 
white paper to the production of heavy shades in the standard 
grades and specialties. Past experience has proved that efficient 
progress in methods of application has been aided by the coopera- 
tion of paper and dyestuffs manufacturers, and the necessity for 
such cooperation will be made apparent in the following pages. 
It is the purpose of this Section to place before the reader such 
information on dyestuffs and their application to paper as is 
essential to the production of the proper shades and colors. At 
the same time, a foundation will be laid for the subsequent work 
that will ultimately be done in connection with the general 
advancement in manufacturing operations. 

While a knowledge of chemistry and physics is of great advan- 
tage in studying the application of dyestuffs to paper, it is not as 
important as a thorough practical knowledge of the working 
qualities of the individual dyestuffs and of the stocks on which 
they are used; consequently, no further knowledge of chemistry 
will be required than is contained in the Section on Elements of 
Chemistry, Vol. II, which the reader is assumed to possess. 

Superintendents, beater engineers, and students of paper 
manufacture should be familiar with the properties of the various 
§5 1 


groups of dyestuffs, the variety of dyestuffs in each group, and 
the action of individual dyestuffs during the process of coloring. 
A practical working knowledge of the equipment used, and of 
the different methods of application as applied to various types 
of equipment, should be acquired. The foregoing, together 
with a short history of the dyestufT industry, will form a nucleus 
for a thorough understanding of this subject, which should be 
supplemented by practical experience in the mill. 

2. History of Coloring of Paper. — The coloring of different 
substances has engaged the attention of man from the earliest 
ages. Records of the coloring of fabrics go back as far as the 
year 2000 B. C, With the beginning of manufacture of hand- 
made papers, it is recorded that vegetable stains and minerals 
were used for coloring purposes. 

Until the latter part of the nineteenth century, paper was 
colored with pigments, vegetable colors, and lakes (insoluble 
compounds made from vegetable colors); but, due to the com- 
paratively few pigment and vegetable colors produced, the 
variety, quality, and uniformity of shades thus obtained were 
in no wa3^ comparable to those made possible by the discovery 
of the aniline dyestuffs. 

3. Mauve, the first aniline dyestuff, was discovered by Sir 
William Henry Perkin, in 1856, in an attempt to manufacture 
synthetic quinine by the oxidation of aniline oil. Although this 
discovery was quite accidental, it formed the basis for the develop- 
ment of many other aniline dyestuffs, and for the subsequent 
adoption of them by the textile industries. While the manu- 
facture of aniline dyestuffs thus dates back to 1856, their use 
in the paper industry was negligible until about the yesiT 1890, 
when their cost of manufacture had been reduced to a point that 
permitted their use in the manufacture of paper. Between 1890 
and 1914, there was a wonderful development in the European 
dyestufT industry, not only in the variety of products applicable 
to paper but also in the reduction to very low levels of the cost 
to the consumer. 

4. While the first aniline dycstuff was discovered by an EngUsh- 
man, keen interest was exhibited by both France and Germany 
during the early stages of the development of the dyestuff 
industry. As time went on, Germany began to realize the 


importance of such an industry, and she gradually drew ahead 
of her English and French rivals, due more to the active support 
of the German Government, which subsidized the young industry, 
than to any superiority of the German chemist over his con- 
temporaries in other countries. While the business was still in 
its infancy, the German Government recognized clearly the 
advantage of building up an industry that would yield good 
profits in peace times, and which could readil}'- be converted 
into an organization for the manufacture of munitions of war. 
That the Germans were correct in their successful efforts to 
secure a strangle hold on the dyestuff and organic chemicals 
industries was amply proved by the events subsequent to 1914. 
Prior to 1879, the Germans had absolute control of the dyestuff 
industry in the United States. Although from that time to 1914, 
there were a few companies in this country manufacturing 
dyestuffs, they were made principally from German intermedi- 
ates. Through the indulgence of the Germans, the American 
companies were allowed to continue operations, but only to an 
extent by which the Germans might benefit through considera- 
tions and regulations of the tariff. Several efforts were made by 
domestic companies to become established on this continent, but 
they could not compete, on a scale of appreciable magnitude, 
with the subsidized companies of Central Europe. 

The recent World War, with its resulting shortage of dyestuffs, 
proved the necessity for the establishment of a domestic dye 
industry. Those concerns which were making small quantities 
of a few dyestuffs rapidly expanded, in the effort to meet the 
abnormal demands caused by the stoppage of the European 
supply. Many new companies were formed, with the result 
that, todaj'-, the American dyestuff manufacturers are able to 
meet the demands of the paper industry. 

5. Source of Aniline Dyestuffs. — Aniline dyestuffs are deriva- 
tives of certain products obtained from the distillation of coal 
tar. By subjecting these crude products or crudes, as they are 
termed in the trade, to certain chemical processes, intermediates 
are obtained. On further treatment, the intermediates may be 
converted into dyestuffs, explosives, poisonous gases, and drugs 
or pharmaceutical preparations. A plant which, in normal times, 
is devoted to the production of dyestuffs can thus be readily 
converted into one for the manufacture of various chemicals 
used in warfare; and, at the same time, it can produce the 


dyestuffs required by the manufacturers. More important even 
than plant equipment is the training of a large staff of chemists 
and chemical engineers, who are fitted bj^ education and experi- 
ence to carry on any research work connected with the exigencies 
of warfare that they may face. The bond is close between the 
dyestuff industry and the organic chemicals industry- as a whole. 
There is no branch of chemical industry where a thorough appre- 
ciation of the principles of chemistry is more necessary, or where a 
greater variation in plant methods and equipment must be 

Pigments and many natural organic dyes, which had not been 
on market for several years, owing to the scarcity of aniline 
dyestuffs during the years 1914-1918, inclusive, are now available 
in various forms. At the present time, the paper industry has 
at its disposal a complete line of the aniline dyestuffs necessary 
for its use, together with a larger volume of pigments and natural 
organic dyes than were available before the war. 



6. Definitions. — Dyeing may be defined as the art of coloring 
(or changing the color of) any material by bringing it into contact 
with another material of different color in such a manner that 
the resulting color will be more or less permanent, not being easily 
altered when the dyed material is subjected to such influences as 
heat or light, washing, etc. The material used to change the 
color of some other material is called a dye or dyestuff. It is not 
sufficient merely to bring into intimate contact two materials of 
different color. For instance, very finely powdered charcoal 
may be thoroughly mixed with water to form a black solution; 
into this, a white cotton cloth may be dipped and soaked, thereby 
turning the cloth black. The cloth will not be dyed, however, 
because by a thorough washing and rubbing, it can be made to 
resume its original color. To be truly dyed, the coloring matter 
(dj'e, or dyestuff) must adhere or cohere to the fiber, and it must 
be more or less unaffected by such physical and chemical changes 
as the material mav receive. 


If a material has been so colored that its color is changed very 
little, if at all, by the action of light, heat, washing, etc., the dye 
used is said to be fast, and the resulting color is said to be a fast 
color; if, however, the color changes, usually becoming lighter, 
or changing shade, it is said to fade. 

Some dj^es will not produce the desired color by direct action 
on the fiber — they will not stick, as it were. In such cases, 
another agent, called a mordant, is used. The mordant adheres 
to the fiber, the dye adheres to or combines with the mordant, 
and the dye thus becomes mordanted, or fixed. A mordant is 
defined as "a substance which, when applied to the fiber in 
conjunction with a dyestuff, combines with the latter to produce 
a useful color." 

7. Three General Groups of Dyes. — Coloring matters are 
divided into three general groups; namely, aniline dyestuffs, 
pigments, and natural organic dyes. The first two groups will 
be discussed in detail; but in regard to the third group, all that is 
necessary to say here is that the natural organic dyes^ include 
logwood, the red woods (camwood, barwood, sanderswood, 
brazilwood, peachwood), madder, cochineal, the j^ellow woods 
(weld, old fustic, quercitron bark, flavine, young fustic), and 
Persian berries. All these natural organic dyes require the use 
of mordants, or other chemical treatment. According to Regi- 
nald Brown, F. C. S., indigo, turmeric, orchil, and catechu are 
used without mordants. 

8. Reasons for Using Aniline Dyes. — Of the three groups of 
dyes, the first group is used more largely than either of the others 
in the manufacture of paper. Though certain pigments are used 
in considerable amounts, aniline dyes predominate for the 
following reasons: (a) They embrace a wider range of shades 
than pigments or natural organic dyes; also, on account of their 
great varietj^, they afford more of an opportunity for choice 
as regards cost, tinctorial power, brilliancy, and resistance to 
various influences, such as light, acids, or alkalis, (b) Aniline 
dyestuffs do not decrease the strength of finished paper, as is 
the case with pigments, (c) They are easier to handle in. the 
mill than pigments or natural organic dyes, both with respect to 
manipulation and to uniformity of results, (d) With few 
exceptions, aniline dyes are the cheapest. 

' None of these now are used much, if at all, in the paper industry. 



9. Classification of Aniline Dyes.^ — From the standpoint of 
})ractical application, aniline (or coal-tar) dyestuffs are not 
classified according to their chemical constitution, but are grouped 
in accordance with their general properties. There are five such 
groups; namely basic, acid, direct (or substantive) dyestuffs, 
sulphur colors, and pigments from vat dyes of the anthracene 
series. Each group has distinctive chemical and physical prop- 
erties relative to their action on the fiber and in their method of 
application. In order to identify a color by name, it is necessary 
to know three things: first, the trade name; second, the shade or 
the distinguishing letter; third, the manufacturer. 

10. Trade Names and Distinguishing Letters. — The trade 
name usually bears a reference to the class, properties, chemical 
constitution, or color of the dye, such as acid blue, fast red, 
methylene blue, etc.; but, in many cases, it is simply an arbitrary 
name, such as Auramine or Rhodamine, given to it by the dis- 
coverer or by the first manufacturer. 

No fixed rule applies to the distinguishing letters following the 
name of the dyestuff. However, R usually applies to a red shade, 
2R to a still redder shade, G or Y to a yellow shade, B to a blue 
shade, and X or Cone, to the more concentrated brands. Some 
form of the name of the manufacturer often prefixes the trade 
name, in certain cases, this designates their class. For example, 
the names Du Pont, pontacyl, pontamine, and ponsol, of E. I. 
DuPont de Nemours & Co., signify basic, acid, direct, and vat 
dyes, respectively. 

11. Basic Dyestuffs. — Basic dyestuffs are so called because 
they have a similarity in their chemical behavior to such inorganic 
bases as caustic soda (NaOH) or ammonium hydrate NH4OH. 
They appear on the market in the form of a salt, such as the 
chloride, acetate, oxalate, or nitrate, in which the molecular 
formula corresponds to (dye base)-oxalate, (dye base)-chloride, 
etc. Basic dyestuffs are marketed in this form because the color 
base itself is insoluble in water and must be treated with an acid, to 
form soluble salts; just as anihne, which is but slightlj^ soluble, 
becomes the very soluble chloride on treatment with hydro- 
chloric acid. 

Basic dyes are characterized by their extreme brightness and 
great tinctorial power; but, as a class, they possess poor fastness 


to light. All basic dycstuffs can be mixed and dissolved with 
others of the same class ; but they should not be mixed or dissolved 
with acid or direct colors, as they would be thereby precipitated 
as color lakes.' Not only would the color then be wasted, but the 
precipitated lake would be apt to produce color spots on the 
finished paper. 

Basic dyestuffs are very sensitive to hard water, bicarbonates 
of lime or magnesia, or any free alkali. When an alkali of this 
kind is present, it neutralizes the acid, setting free the insoluble 
dye base, which will appear in the finished paper as a color 
spot; 50 parts per million of bicarbonates may give trouble. It is 
for this reason that the recommendation is here made that acetic 
acid be added before the dyestuff, if trouble from this source is 

When dissolving basic dyestuffs, they should never be boiled; 
they are best dissolved at a temperature that does not exceed 
200°F. Upon boiling, there is a tendency to hydrolyze the dye- 
stuff salt, thereby forming an insoluble base, which greatly 
reduces the coloring power of the dyestuff. Certain basic dye- 
stuffs, such as auramine, basic brown, Victoria blue, should 
never be dissolved at a temperature exceeding 160°F. 

12. Acid Dyestufifs. — Acid dyestuffs also appear on the market 
in the form of a salt; they are so named because, in the salt, the 
dye radical takes the place of the acid constituents and gives a 
molecular formula such as sodium-(dye acid) or potassium-(dj^e 

As a class, acid dyestuffs have a lower coloring power than basic 
dyestuffs, but they are much faster to light; and on mixed 
furnishes, give more even dyeings than basic or direct dyestuffs. 
Acid dyestuffs have no direct affinity for cellulose fibers ; they are 
merely mordanted, or fixed, to the fiber by the presence of size and 

13. Direct, or Substantive, Dyestuffs. — The direct, or sub- 
stantive dyestuffs are also salts of color acids, being differentiated 
from the acid dyestuffs by the fact that they do not require alum 
or, when used in the textile industry, an acid, to develop their 
tinctorial power. These dyestuffs are so named because of their 
affinity for cellulose fibers. As a class, the direct dyestuffs have 
less tinctorial power than the basic dyestuffs; but, in all cases, they 

1 A lake is an insoluble color compound. 


are much faster to light than the basic d^'es, and, in some cases, 
than the acid dyes. Some direct dj'estuffs are sensitive to hard 
water, some of the members of this group being precipitated in 
the form of insoluble lime or magnesia salts. 

Direct colors are best dyed at about 140°F. with the addition of 
salt (sodium chloride) to exhaust {i.e., absorb or use up) the color 
more freely. Although this procedure is used in mills making 
blotting papers, it is very seldom resorted to on sized papers, 
because of the effect on the sizing of the finished sheet. Because 
of their property of having a direct affinit}- for the fiber, even 
though these dyestuffs are generally used for unsized papers, 
the backwaters^ in such cases are not always perfectly clear: 
but they may be cleared by adding a small amount of alum. How- 
ever, alum has the property of decidedly deadening the shade of 
all direct dyestuffs; and it is for this reason that the shade pro- 
duced with a particular dyestuff will be different on sized and 
unsized papers. 

14. Sulphur Dyestufifs. — The sulphur dyestuffs derive their 
name from the fact that sulphur has a predominate part in their 
manufacture. They are insoluble in water, but are soluble in alka- 
line sodium sulphide, in which the dyestuff is reduced. This 
reduced form adheres to the cellulose fiber, and it is oxidized upon 
exposure to the air, to form the color desired. The onh' asset 
of sulphur dyestuffs is their cheapness; but, with the exception 
of a very few isolated cases in the manufacture of heav}- black 
shades, the decrease in the initial cost of the d3'estuff will not offset 
the greatly increased cost of manipulation. While important to 
the textile industries, the use of sulphur dyestuffs in the paper 
trade is practically negligible at the present time. 

15. Vat Colors. — The vat colors are pigments^ that are prepared 
by special processes from the aniline dyestuffs themselves. These 
pigments are, for the most part, fast-to-light colors that are used 
almost exclusively in tinting higher-grade white papers. For 
example, ponsol colors for paper (called indanthrene colors before 
the war) are a special form of the insoluble textile dyestuff of 
that name. These colors are the fastest known. On account 

1 The water that drains off from the fibers during formation of the paper 
on the machine wire. 

2 A pigment is a solid which, on being reduced to a powder and mixed 
with a vehicle, can be used as a paint or a dye. A pigment is insoluble 
in the vehicle, while a dye is dissolved in it. IVlost pigments are inorganic 
compounds. In coloring paper, they are sometimes added in the dry 


of being so much faster to light than the majority of the stocks, 
the}^ shovikl never be used in paper that contains less than 50% 
rag unless certain properties of the finished paper must be 
obtained ; for, as will be shown later, there is no need of using, in 
a paper, dyestuffs that are more permanent than the stock from 
which the paper is made. Other types of pigment color made 
from aniline dyestuffs include heliopont colors, solar blues, etc. 
In all these cases, the dyestuffs are used as pigments, and they 
maj^ be thrown into the beater in the dry state or in water 


16. Classification of Pigments. — There are no general rules 
for the nomenclature or classification of the various pigments now 
in use in the paper industry. Each pigment is a separate and 
distinct chemical compound; hence, those here mentioned will be 
treated individually. 

As a rule, pigments are very low in tinctorial power, and they 
have the disadvantage of lowering the strength of the paper in 
which they are used; but they increase the weight of the paper, 
which is sometimes an advantage. Some pigments have the 
advantage of very low cost, and some are characterized for special 
purposes by great permanence in resistance to light and chemicals. 
Pigments also act as fillers to a certain extent, giving, in certain 
cases, those special characteristics to the sheet that may be 
desired in it. 

The chief types of pigments used in the paper industry are 
ochers, siennas, umbers, red or iron oxide, chrome yellow, 
Prussian blue, ultramarine, sap brown, and lamp black. Pulp 
colors, and certain pigments used in the coloring of coated papers, 
will be discussed later. 

18. Ochers. — Ochers are natural silicates that contain ferric 
oxide or hydrated oxide of iron; they range in shade from yellow 
to brown, depending on the degree of hydration. Ochers are 
marketed as finely divided powders, the degree of fineness having 
a direct bearing on the quality of the product. Freedom from 
grit is an important factor in the use of ochers. 

19. Siennas. — Siennas are natural silicates that contain 
manganese oxide. The range of shade of the various siennas is 
much the same as is that of the ochers. 


20. Umbers. — Umbers are complex silicates that contain a 
high percentage of manganese oxide and ferric hydrate. Umbers 
are a greenish brown in their natural state; but, on burning, they 
become a rich, deep brown, which produces a desirable brown 
shade on paper. 

21. Iron Oxides. — Red oxide, oxide of iron, or Venetian red 

are pigments tliat depend on ferric oxide or ferric hydrate for 
their coloring power; they are used to some extent for the color- 
ing of I'cd sheathing, cheap roofing, and a few paper specialties. 
The use of this product depends a great deal on its quality; for 
high-grade papers, it must be very finely divided and free from 
grit. A great disadvantage to the use of these oxides is the 
didling action on slitter and cutter knives, and the weakening of 
the finished sheet, which is caused by the excessive loading 
required to obtain shades of average depth. 

22. Chrome Yellows.^ — Chrome yellows of various shades, 
ranging from a bright greenish yellow to an orange, are manu- 
factured by mixing lead acetate with sodium or potassium bichro- 
mate. Chrome yellows are usually found on the market in the 
form of a paste, a generally accepted shade being used under 
the name of canary 'paste. They can also be made directly in the 
beater, by mixing lead acetate with the stock and adding suffi- 
cient sodium or potassium bichromate to precipitate the lead as 
chromate. Chrome yellows are comparatively fast to light, 
but are very sensitive to heat and acids, which makes it difficult 
to maintain a uniform shade throughout a run, owing to variation 
of temperature in different beaters. 

23. Prussian Blues. — Various Prussian blues, both in the 
soluble and insoluble form, are used for coloring. They are 
made by the precipitation of ferric sulphate with potassium 
ferrocyanide. The soluble form of Prussian blue is obtained by 
boiling the precipitate obtained by the reaction of ferric sulphate 
and potassium ferrocyanide in an excess of ferrocyanide solution. 
Prussian blue is an economical color to use, and it possesses ver}^ 
good fastness to light. It has two disadvantages; namelj^, 
it is very sensitive to alkali, and it appears greenish under artifi- 
cial light. Soluble Prussian blue must not be confused with 
the extensively used aniline dyestuff known as soluble blue or 
acid blue. 


24. Ultramarines. — Ultramarines of various shades of blue, 
from greenish to reddish tone, are used for the tinting of higher 
grades of white papers. They are soluble silicates of sodium 
and aluminum, containing some sodium sulphide, made by 
admixture of sodium carbonate, sodium sulphate, claj^, sulphur, 
silica, and charcoal. After heating to a molten mass and cooling, 
the mixture is finely ground and washed. Ultramarines have 
the decided disadvantage of being sensitive to acids and alums. 
The so-called alum-resisting ultramarines are superior for use 
in the paper industry. The greater the percentage of sulphur 
and silica in the ultramarine the redder in tone and the more 
resistant to alum it becomes. 

25. Sap Brown. — Sap brown, a brown coloring agent of 
unknown composition, has a limited use in cheaper grades of 
paper. It is used more as a dyestuff than as a pigment, due to the 
finely disintegrated state of its particles in solution. It has the 
advantage of being fast to light, but it is sensitive to hard water. 
On account of its non-uniformity, difficulties are experienced in 
maintaining uniform shades. 

26. Paris Black. — Lamp, carbon, or Paris blacks, produced as 
soot by the incomplete combustion of various oily organic 
compounds, are used to some extent for the production of gray or 
black papers. Lamp black, when used in large amounts, has a 
tendency to streak the paper; it makes paper rub badly, and it is 
a decided nuisance in the beater room. Due to its fine state of 
division and low density, it is apt, through careless handling, 
to get into the air and settle, in the form of soot, on other 
material in the beater room; however, this can be avoided by 
careful handling. The lamp black either can be weighed into a 
paper bag, and the whole bag thrown into the beater, or it can 
be made into a paste with hot water. It is difficult to obtain 
uniform results with lamp black, because the depth of the shade 
depends on the length of time and manner of beating. 


27. Source of Coal Tar and Crudes. — Aniline dyestuffs are 
manufactured from coal tar, whicli is a by-product of gas and 
coke making. The percentage of coal tar obtained depends on 
the method of distillation of the coal. The average production 


from one ton of coal is, approximately, 12,000 cubic feet of gas, 
1200-1500 pounds of coke, and 120 pounds of coal tar. 

28. Crudes. — Coal tar contains several different crudes, the 
most important of which are benzene, toluene, xylene, phenol, 
naphthalene, and anthracene, and these are separated from one 
another by fractional distillation. Each crude forms the starting 
point from which certain intermediates of importance to the 
dyestuff manufacturer are made. The residue, or pitch, which 
is left after the crude of highest boiling point has been distilled, 
is used for paving, roofing, and for other similar purposes. After 
separating the crudes into groups, each group is further purified 
by additional distillation or crystallization, and it is then ready 
to be used in the manufacture of intermediates. 

29. Manufacture of Intermediates. — The coal tar inter- 
mediates may be divided into three groups; nameh', benzene 
intermediates, naphthalene intermediates, and anthracene inter- 
mediates, all of which are derived by subjecting the purified 
crudes to various chemical operations, such as sulphonation, 
nitration, reduction, oxidation, fusion, and condensation. The 
yields and purity of the intermediates formed during these 
operations are greatly influenced by temperature, pressure, 
concentration, and other factors. By varying the foregoing 
operations, and the conditions under which they are conducted, 
a large range of intermediate compounds is obtainable. 

30. Azo Dyes. — The scope of this work will not permit of a 
detailed account of the different processes entailed in the manu- 
facture of intermediates and dyestuffs; but to exemplify the 
nature of such operations, the following description of one of 
the most important types of reaction is given. Most of the 
direct, a large number of the acid, and a few of the l^asic dyestuffs 
are called azo dyes, because of the nature of the reaction that takes 
place in their formation from the crudes into the finished dyestuffs. 

31. Diazo Dyes. — When a benzene or naphthalene inter- 
mediate containing an amino (NH2) group is treated with 
sodium nitrite and hydrochloric acid at a temperature around 
5°C., a process known as diazotization takes place. The amino 
group of the intermediate reacts with the nitrous acid in such a 
way as to form a diazo compound (see Section on Elements of 
Chemistry, Vol. II, Art. 243), which will readily unite with other 
intermediates, forming a series of dyestuffs, according to the 


substances so combined. Since there is an endless number of 
intermediates that may be diazotized, and since there are just as 
many more with which the resulting compounds may combine, 
it can readih' be perceived that an enormous number of dye- 
stuffs can be formed by substituting different intermediates. 
Proceeding a step farther, the intermediate with which the 
diazo compound combines may possess an amino group that is 
also capable of being diazotized and combined with a third 
bod3^ In man}^ dyestuffs, four intermediates are thus linked up; 
in some cases as many as five are employed. 

32. Manufacture of Vat Colors. — While the vast majority of 
basic, acid, and direct dyestuffs are made from benzene and 
naphthalene intermediates, the vat colors are made from the 
anthracene intermediates by certain processes of sulphonation, 
causticization, fusion, etc. These are the most difficult dye- 
stuffs to manufacture, because very slight variations in manu- 
facturing conditions produce entirely different results. The 
vat dyestuffs are so ca'led because they must be reduced in an 
alkaline solution before applj^ing to the cellulose fibers. Since 
the}' are the fastest to light of all known dyestuffs, and since 
reduction is not possible during the manufacture of paper, these 
colors are prepared in a special form for the use of the paper 
industry- by reducing to the leuco-compound (or colorless form) 
in an alkaline solution with caustic soda and glucose, at high 
temperature, and re-oxidizing in the air, to form pigments of a 
very fine degree of subdivision. 


33. Importance of Standardization. — More important to the 
consumer of dyestuffs than the details concerning their manu- 
facture is the standardization of the finished product. In order 
to color the paper uniformly, the beater engineer must decrease 
the number of variables with which he has to contend. He 
must be assured that when he has once secured a color formula 
for a given furnish, every barrel of the dyestuff he receives under 
a given name or designation shall be absolutely uniform with 
respect to strength and shade. 

34. Methods of Standardization. — In the manufacture of 
paper, it is a physical impossibility to hold the basis weight 


absolutely constant; likewise, in the manufacture of dyestuffs, 
it is impossible for every run of the crude dyestuff to be of exactly 
the same strength and shade. For this reason, a standard of 
strength and shade for each individual dj^estuff is adopted by 
the manufacturer, the strength of this standard being slightly 
less than the average strength obtainable in the crude product, 
or crude charges, as they are called. All dyestuffs, after being 
filtered and dried, are ground to a fine state of subdivision, and 
are compared in strength and shade with the standard adopted 
by the manufacturer. One charge, for instance, may be slightly 
Tedder than the standard, while the next may be slightly greener; 
different lots are mixed together with varying amounts of the 
standardizing agent, to produce the finished dj^estuiT, which is 
exactly the same in strength and shade as the standard adopted 
by the manufacturer. 

35. Standardizing Agents. — The standardizing agent most 
used for basic dyestuffs is dextrine, while common salt NaCl or 
Glauber's salt Na2SO4.10H2O is used for acid and direct dyestuffs. 
Other standardizing agents used in isolated cases are sugar, sodium 
phosphate, and soda ash. An erroneous impression prevails 
among certain consumers that dyestuffs containing any of the 
chemicals just mentioned are more or less adulterated. How- 
ever, a little reflection will show that this is the only way by which 
the absolute uniformity of every product can be controlled by 
the dyestuff manufacturers, and that the selection of a standardiz- 
ing agent is so made as not to interfere with any subsequent 
operations of paper manufacture. 

36. Reduced Brands. — The practice of adding a standardizing 
agent to the dyestuff is sometimes abused by unscrupulous con- 
cerns, which make large profits by reducing the strength of the 
standard brands of the manufacturers; this is one cause for the 
excessive number of dyestuffs of varying concentrations and 
shades on the market, and it results in a great deal of confusion 
to the consumer. These are known as reduced brands; and 
whenever such dyestuffs are placed on the market, a definite 
comparison of their strength with that of the concentrated brands 
of standard manufacturers should be given. In certain cases, 
reduced brands work more efficiently in the mill than the con- 
centrated brands, especially where small quantities must be 
weighed. An example of this is the case of rhodamine B extra 


and rhodamine B, the former being five times the strength of the 
latter. The latter is more generally used in the paper industry, 
because of the great strength of the rodamine B extra, which 
makes the weighing of the concentrated form, in tinting white 
papers or for shading, practically impossible, within the degree 
of accuracy that must be maintained. Until the reliability of 
the source of supply is established, laboratory tests should be 
made on the product samples submitted and, also, on all supplies 
of dj'cstuffs received. 

37. Mixtures of Dyestuffs. — Mixtures of dyestuffs are made 
by all dyestuff manufacturers, and they are sold to the trade 
under either a given name or under a mixture number. They 
are made by combining two or more dyestuffs to produce a 
particular shade, by mixing them, together with a standardizing 
agent, in a standard mixer. Efficient paper-mill practice has 
proved that, except in special cases, the use of mixtures should 
be avoided whenever possible. The principal exception to this 
rule is in the use of mixtures of methylene blue and methyl violet 
for the tinting of the cheaper grades of paper, such as newsprint; 
but, even in this case, the authors of this Section consider it to 
be the best practice to use the individual dyestuffs, in order to 
shade back and forth in the mill, because of the variation in 
stocks during different parts of the year. 

38. Theories of Dyeing. — Among the various theories of dyeing 
that have been advanced are the mechanical theory, the chemical 
theory, the solid solution theory, and the adsorption theory, 
A full discussion of this subject is not advisable in this work; 
but, for information concerning these theories or for further infor- 
mation on the manufacture of intermediates and dyestuffs, the 
reader is referred to the various books on dyestuff manufacture 
and on textile dyeing, such as : Erfurt, The Coloring of Paper; 
Mathews, The Application of Dyestuffs, and the literature of 
dyestuff manufacturers. 



39. The Work of the Laboratory. — The laboratory work in 
connection with the testing of dyestuffs should be divided into 
four general groups: first, a test for strength and shade on all 




samples of competing products submitted by manufacturers; 
second, a laboratory check on material received against standard 
samples, to determine whether the dyestufT being tested is stand- 
ard in strength and shade; third, laboratory tests to be made to 
determine the composition of mixtures of dyestuffs and the 
chemical identity of individual dyestuffs or mixtures; fourth, the 
approximate matching of mill shades, as a guide to subsequent 
matching in the mill. 

Fig. 1. 
Fig. 1 (see " Equipment," Arts. 40, 41) shows the operating bench, on which is mounted the 
equipment necessary for producing a continuous sheet of paper. Tliis consists of a motor, 
mounted on a frame below the table and driving directly the two small beaters that are 
shown on the table. From the countershaft at the left of the table, a belt drives the small 
pump that is used for circulating and agitating the stock in the stock chest, or for deliver- 
ing the stock into the head box. The stock is delivered from the head box to the vat of 
the paper machine. A belt also drives the small white-water pump, whose delivery is 
shown coming over the edge of the head box, and which is controlled by a valve. The 
paper machine consists of the vat, in which turns a mold covered with wire cloth, and 
over which travels the felt that picks up the paper deposited on the wire. The felt trans- 
fers the paper to the large drying cylinder, shown at the far left, to which the paper sticks 
and by which it is dried and given a finish. The last belt from the countershaft drives 
this dryer through a worm gear. The small beaters are driven direct from the motor shaft. 
By matching shades on a miniature machine of this kind, actual machine conditions, such 
as return of white water, drying temperatures, etc., are approximated. 

40. Laboratory Equipment. — In addition to the general equip- 
ment that the ordinary laboratory has, consisting of chemical 
glass and porcelain ware, burettes, graduated cylinders, pipettes, 
beakers, volumetric flasks, distilled water, hot plates, etc., the 


Ifn^'lf TT"'"'^ '' ""''^''^'-y ^o^- the special work in connec 
tion with the testing of dyestiiffs- 

canicitf f t'"" h"'"'/ '''" ' P°"^^^ '' ' P«--l« dry stock 
capacitj , the size depending on the amount of testing to be done 

A washer on such a beater is of decided advantage. 

beaL Tht" '"''"' '' k' "''^ '' '^''^''^ '^' P"lP from the 
cuttW t^e Lr'"/'" ^" ^«-veniently and cheaply made by 
cutting the bottom from an ordinary galvanized-iron pail and 

smpf blatt°:^l tld'^ter^'S orpfner'nl* At', '°' drying test sheets. The 
either beater, the pressure of the^oll nn fll k T' fl"* ^^^ ^?'"«« °°e about 8 pounds In 
simlar to that used on Z regular mlf beaters ^^onH ""\ ^^ ^^^"^^^^ "^^ aTechanism 

untd exactly the right shade is secured, as indicated hi onm^" '" successive quantities 
When the proper shade has been obta ned the tfu n 1 m.^ •'?" \'*^ *^« ^est samples, 
sheet machine, and it is then Hricr?Tr; +1; Ti" ■ ^ P ',^ ""*'^'<^ "^to sheets by means nf o 
cylinder is fitted with a felt!"and lith a steanTinfet'^and'^f '^h°"" 'V^' illustration"' This 
machine dryer. As shown n the illustration th^f.,^ r "^"^ •''■''**''" O"*'*-*- "ke a paper- 
larger beater is used when Tlarse nnmhprTf 1^^" ''"*' '"''""'« a pressure gauge Tho 

t.r' " '"°^^^''^°^'^"' beaS"act"on^rha°nTsTossibYe';!;'h't?'' '''■ -''-' Jtircos.slr; 
beaters may also be used as supplementarv tn nf^ » • th*",.^"'''"" beater. These 

machmeis driven independentlyTftT^wniecUmotT;.'''"""* ''°"" ''^ ^'^- '■ Ea^h 

covering it with a piece of paper-machine wir 
",stenmg a piece of paper-machine wire to a 
(3) Five gallon crocks, with covers, for st 

r , . - . ■; ^ t-"K^x-xiia,uiiiut; wire, or by merelv 

fastening a piece of paper-machine wire to a wooden frame 


oring moist pulps. 




(4) A set of power-driven stirrers, to stir the mixture of pulp, 
color, size, and alum. In case the amount of work of this type 
that needs be done is limited, and the cost of installing such a 
set of power-driven stirrers is not warranted, the writer has 
found several types of egg beaters on the market that are very 
suitable for this work. 

(5) A suction pulp mold or funnel, made from heavy sheets of 
copper, in which paper-machine wire is tightly stretched. This 

Fig. 3. 

Fig. 3 .shows two of the work benches in the color laboratory. On the bench in the rear 
are seen the handles of a receptacle for keeping samples of beaten pulp. Large quantities 
of pulp can be weighed on the big scales, while small amounts of dyestuffs, or dried sheets of 
paper, can be weighed very accurately on the delicate balances that are shown farther 
down the bench. A letter press, used for flattening sheets, can be seen at the end of the 
bench. On the Isench, in the foreground, arc the receptacles for the standard pulps required, 
and the mixing cups for matching shades. It will be noticed that the agitators in these cups 
are driven by a countershaft, which runs the length of the bench and is driven by a small 
electric motor. Above the bench are the jars and bottles containing the various dyestuflf 
solutions, and the rosin, alum, starch, clay, and other materials that may be required in 
making certain papers. It is necessary to approximate, in so far as is possible, all con- 
ditions and factors of furnish and manufacture. 

wire should be reinforced with a coarser copper-wire screen, 
supported by a perforated copper plate. The neck of the funnel 
should be fitted with a rubber stopper, so arranged that it can be 
mounted either in a suction flask or, preferabl}^ in a large copper 
receptacle, fitted at the bottom with a stop cock, to allow the 
back waters to drain away when the box is not in use. An 




advantage in using the suction flask is that the color of the back 
waters can easil}' be seen, which permits an estimation of the 
retention of the dyestuff by the paper. Suction may be obtained 
by the ordinary water-suction pump or by means of a small 
vacuum pump, connected to a large intermediate vacuum 
chamber in order to secure a constant suction when the mold is 
in use. 

Fig. 4. 

Fig. 4 shows a recently developed sheet machine. It consists of a piece of Fourdrinier 
wire, supported and held fiat by a frame on a leg, and so adjastable that it can be made 
level, and of a box (tipped back in the illustration), which makes a water-tight, machined 
fit wnth the frame. A plug valve belo%v the frame (which forms a box) controls the drain- 
age of the water from the stock, which is allowed to become quiescent before being drained. 

(6) Several thicknesses of old canvass dryer felt, cut about 16 
inches square, to be used with filter paper and blotting paper to 
couch the sample. 

(7) A dryer, with a revolving drum from 1 foot to 4 feet in 
diameter, made of copper or bronze, either steam or electrically 
heated, together with a motor for revolving the drum, so the 
paper sheets are carried in between the surface of the hot drum 
and the dryer felt. 

(8) A supply of one-quart white-enameled cups and of wide- 
mouth glass bottles. 


(9) A rough balance, sensitive to 0.01 gram, for weighing 
pulps; this balance is in addition to a chemical balance for 
weighing to 0.0001 gram. 

41. Additional Laboratory Equipment. — There is practically 
no limit to the additional expenditures that can be made for 
laboratory equipment. There are miniature paper machines on 
the market, ranging in size from 4 inches to 30 inches trim, which 
approximate the larger paper machines in the majority of details. 
Other pieces of experimental equipment used in laboratories for 
special purposes are available. Among these may be mentioned 
a tissue-dyeing machine, so arranged that the paper passes 
through a color box and squeeze rolls, to remove the excess of 
color; and a miniature two-roll, three-roll, or four-roll calender 
stack, equipped with water or color boxes, for making experi- 
mental runs on calender coloring. 


42. Identification of Coloring Matters. — The identification of 
various coloring matters requires considerable experience and 
patience in studying the color reactions by which they are 
identified. To investigate this question thoroughlj^, requires 
years of experience. However, since all large dyestuff manu- 
facturers operate a technical service department in which men 
who have made this problem a life study are employed to handle 
this work, the paper manufacturer will obtain more satisfactory 
results by depending on the dyestuff manufacturer for informa- 
tion on any dyestuffs he wishes to have identified. 

Nevertheless, a general knowledge of the separation of dye- 
stuffs into their various groups, and of the tests of behavior 
toward different chemicals, is important to the paper manu- 
facturer; it enables him to generalize his information, and it 
assists him in making paper that will meet special requirements. 

43. Separation of Aniline Dyestuffs and Pigments. — The 
first step is to determine whether the coloring matter under 
consideration is a soluble aniline dj^estuff or a pigment. The 
pigment colors may be easih^ identified as a class by their insolu- 
bility in water, soluble Prussian blue being the exception to this 
rule. The pigment colors used in the paper industry being few 


in number, and possessing certain characteristics of appearance, 
tinctorial power, etc.,' are comparatively easy to identify. 

If the coloring matter is soluble in water, the following pro- 
cedure should be adopted to determine: first, whether the dye- 
stuff is a single color or a mixture; second, to what group it 
belongs; thu-d, to determine, if possible, the individuality of the 
dyestuffs in its particular group. 

A small amount of the dyestuff is placed on the point of a 
knife or spatula, and is gently blown onto a piece of wet pulp or 
filter paper; this action is called a blowout. If the dyestuff 
is a mixture, the sample is separated into its component parts, 
each individual particle showing a spot of different color. 

44. In some cases, where the sample being tested is a mixture 
of two dj^estuffs somewhat similar in shade, it may be difficult 
to distinguish the component parts from a blowout on wet pulp 
or filter paper. As a check to the above method, a small amount 
of the sample is placed on a blade or spatula and blown onto the 
surface of about 10 c.c. of sulphuric acid, contained in a small 
porcelain evaporating dish. Different dyestuffs give different 
color reactions with sulphuric acid, thus indicating at once 
whether the sample is an individual dyestuff or a mixture. 

45. Determination of Mixtures. — Some dyestuffs are mixtures 
obtained by evaporating to dryness solutions of two coloring 
matters that have previously been thoroughly mixed. Such a 
mixture can be determined by making successive dyeings on 
skeins of plain cotton, tannin-mordanted cotton,^ or wool, 
depending upon whether the mixture has been determined to be 
a basic, acid, or direct dyestuff. If the color is a single dyestuff, 
the skeins made by a series of dyeings to exhaust the bath, will 
show a gradual shading down in strength of the same shade. 
If the dyestuff is a mixture, then the first and last dj^eings will 
differ in shade. Allowance must be made for the variations in 
strength of the different dyeings, as such variations often 
cause an apparent variation in shade. 

' Tannin-mordanted cotton can be prepared by inserting boiled-out 
cotton yarn into a bath containing 3% tannic acid, based on the weight 
of the yarn, at 140°F. Raise the temperature of the bath to 200°F., and 
hold for one hour. Steep until next morning, when the yarn should be 
wrung out and dried, but not washed. Dissolve 1% to 1-J% tartar emetic 
in water, introduce the dried yarn at 100°F., hold one-half hour, wash, and 
wring evenly. 


46. Separation of Aniline Dyestuffs into Groups. — The second 
question to determine, if the sample has been shown to be an 
individual dyestuff, is to what group it belongs. Only basic, 
acid and direct dyestuffs, and pigment colors, are used in the 
paper industry, and tests for those groups only will be necessary. 
As previously stated, pigment colors can be identified by their 
insolul)ility in water, as indicated when a blowout is made on 
wet filter paper to determine whether the color in question is a 

47. Method of Testing. — Prepare in a test tube a dilute solu- 
tion of the dyestuff; after adding a few drops of acetic acid, 
insert a thread of boiled-out degreased wool and one of tannin- 
mordanted cotton. If the tannin-mordanted cotton is dyed, a 
basic color is indicated; if the wool is dyed, an acid or direct dj'^e 
is indicated. 

In a second test tube containing a dilute solution of the dj'estuff, 
add a small amount of Glauber's salt ; place a cotton thread in the 
test tube and warm the solution. To determine whether the 
thread was actuality dyed or mereh- mechanically colored, remove 
the colored cotton thread and place it in another test tube that 
contains distilled water, and boil. If the cotton retains its color, 
the results indicate that the sample being tested is a direct, or 
substantive, dj^estuff. 

If the sample under examination colors both the wool and the 
tannin-mordanted cotton, repeat the dyeing test in a very dilute 
solution of the dyestuff, to which acetic acid has been added. If 
the sample is an acid dyestuff, it will color the wool; but, if it is 
basic, it will stain only the tannin-mordanted cotton. To sub- 
stantiate the basic character of the dyestuff in the latter case, add 
some tannic acid to a separate fresh solution of the dyestuff, to 
which has been added some sodium acetate; if the sample is a 
basic dye, a precipitate of tannin lake will occur. 

48. Subsequent Steps. — The subsequent determination of the 
individuality of the sample submitted is a process of analytical 
character that requires a long training. To become efficient in 
these methods of determination, which are based upon the 
reactions of the different dyestuffs with weak and strong alkalis, 
weak and strong acids, reduction, and oxidation, would require 
more time and labor than the paper manufacturer or the paper- 
mill chemist could devote to it. As stated before, the dyestuff 


manufacturers have men trained to do this work; and, in all cases 
where the actual identification of the sample is required, the 
sample should be submitted to the technical laboratories of the 
dvestuff manufacturers. 


49. Testing for Strength and Shade. — The testing of a given 
dyestuff for strength and shade is more important than its 
identification, because such tests show the actual money value of 
the dyestuff to the consumer. All work in the laboratory should 
be done on the same stock as that to be used on the run of paper 
for which the particular formula is being worked out. The 
number of pulps kept on hand in the laborator}^ depends on the 
grades of paper made in the particular mill. A laborator}^ doing 
work for a mill making numerous grades of paper should carry the 
following pulps in stock: unbleached sulphite (quick cook), 
unbleached sulphite (Mitscherlich), bleached sulphite, kraft, 
soda, groundwood, cotton linters, and rag stock. 

50. Preparation of Stocks. — These stocks are prepared for 
laboratory use by one of two methods. If the stock is to be 
prepared in the laboratory, it is placed in the miniature beater, 
where it is beaten until it gives the proper feel or freeness test (see 
Sections on Refining and Testing of Pulp, Vol. Ill, and Beating 
and Refining, Vol. IV). The excess of water is then removed by 
means of a suction funnel or a' laboratory pulp thickener. The 
pulp is next placed in a crock, and it is kneaded until the moisture 
present is evenly distributed; the crock must be kept tightly 
covered at all times. In some cases, it is easier to take the stock 
directh' from the beater room, before the size and alum have been 
added to the mill beaters; and, after removing the excess of water, 
the same procedure is followed as with the laboratory-beaten 

51. Moisture Determination. — Moisture determinations should 
then be made, to ascertain the weight of wet pulp that will 
be necessary to make a hand sheet of a required air-dr}- 
weight. These moisture tests are in constant use, and the 
moisture content should be accurately determined at frequent 
intervals. The basis weight for pulp to be used for hand samples 
varies in different mills, but an average of 2^ grams of air-dry 
pulp will make a 6-inch diameter hand sheet of average thickness. 


The moisture content of the prepared pulps should be of such a 
consistency that from 10 to 15 grams of the wet pulp will be equi- 
valent to 2| grams of the dried pulp. Certain pulps, such as 
jute, manila, kraft, groundwood, and old newsprint, are readily 
attacked by mold and bacteria. When fermentation or bacterial 
change occurs, as indicated by the color or odor of the pulp, it is 
advisable to prepare a new supply. 

52. Approximate Methods. — For straight color evaluation work, 
either unbleached sulphite or mixtures of equal parts of unbleached 
sulphite, soda, and groundwood are used; which to use depends, 
of course, on the grades of paper made at that particular mill. 

The dyestuff to be tested should be made up into a standard 
solution, by weighing out on an accurate balance, dissolving in 
hot water in a casserole, and, after solution is complete, pouring 
into a volumetric flask and making up to the proper volume. A 
convenient strength for these solutions is 0.5 gram of dyestuff per 

53. For matching a product sample of dyestuff against a stand- 
ard sample, to determine the strength and shade, the following 
approximate methods are suggested: 

(a) Before the solutions are made up to the required volume, 
spot each of the solutions side by side on a filter paper. Note the 
difference in strength, and increase the volume of one of the 
stronger dye solutions {i.e., dilute it) to the point where further 
tests show the solution to be of equal strength with one of the 
weaker ones. By comparing the volumes of the two solutions, 
an approximation to their relative strengths can be made, which 
will save the time required for determining the actual strength 
test by making hand samples. 

(b) Another approximate method, known as the dip test, is 
made by cutting a piece of heavy filter paper in such a manner 
that it will have two equal legs or forks. The standard solution 
and that to be tested are then placed side by side, one leg of the 
filter paper being dipped into each of the two solutions. Upon 
examining the filter paper after drying, an approximation to the 
relative strengths can be obtained. 

54. Standard Solutions. — In addition to the color solutions, 
which should l)e made up fresh as required, the following stand- 
ard solutions should be kept on hand at all times; namely, size, 
alum, soda ash, and clay. For laboratory work, a convenient 


strength of the solutions of the first three items is 2|%; the 
suspension of clay should be approximately 20 parts of water to 1 
part of clay, and the bottle containing it should be thoroughly 
shaken each time before using. The following description gives 
the methods and relative proportions used very successfully in one 
laboratory, and they can be used as a guide for other laboratories : 

55. On a rough balance, weigh out the samples of wet pulp, 
equivalent to 2.5 grams air-dry weight, and place in a porcelain- 
lined cup. Add 50 to 100 c.c. of water, and mix the stock for 5 
minutes by means of the mechanical stirrers or paddles mentioned 
in Art. 40. At five-minute intervals, add the color solution, size, 
and alum; if fillers be used, they should be added at a five-minute 
interval before the size. After all material has been added to the 
cup, and the total stirring time is equal to 39 minutes, add 
approximatel}^ 500 c.c. of water, stirring continuously for a 
minute or more. 

56. Making Hand Samples.— The diluted pulp is now poured 
into the funnel or mold, and the suction is applied. If a suction 
flask be used, it is rotated, finally, at an angle that will completely 
remove the water that tends to adhere to certain portions of the 
sheet of pulp. The suction is then turned off, and the sheet is 
carefully loosened on one side by means of a spatula. The sheet 
is then lifted from the wire and placed between two sheets of 
filter or white blotting paper. If an ordinary rolling pin be used 
to couch the sample, the sample sheet and blotting (or filter) 
papers should be placed between pieces of ordinary dryer canvass. 
If a wringer is to be used, the amount of blotting or filter paper 
should be doubled, as the sample, covered by this paper, is 
passed through the wringer. The remaining moisture should 
be removed on drying on the rotary drum dryer (Art. 40) or on a 
hot-plate. When drying these hand samples on a drum dryer, the 
sheet should be reversed after every revolution of the drum, to 
hasten the drying and to avoid the danger of burning the color 
to the surface. 

57. Color Formulas. — All color formulas should be given in 
terms of 1000 pounds of stock. When the above-mentioned 
proportions of 2.5 grams of air-dry pulp, a color solution of 0.5 
gram per liter, and 2.5% solutions of size and alum are used, every 
5 c.c. of color solution is equivalent to 1 pound of dyestuff per 1000 
pounds of stock; and 1 c.c. of size or alum is equivalent^to_[10 


pounds of that material per 1000 pounds of stock. ^ When testing 
individual dyestuffs against a given standard for strength and 
shade, a 0.2% dyeing is recommended for basic dyestuffs, and a 
0.4% dyeing for acid and direct colors; i.e. add 10 c.c. and 20 c.c. 
of dycstuff, respectively, to the pulp. 

58. Strength of Yellow Dyestuffs. — For determining the 
strength of yellow dyestuffs, small standard amounts of either 
methylene blue or of safranine are added to the stock of both 
the standard and the product sample dyeings. A greenish 
tint is produced, which registers more distinctly than yellow on 
the eye. The strength of the yellow dycstuff is then determined 
by the degree of shading toward the true shade of either the 
methylene blue or the safranine. 


59. Varieties of Fastness. — For every grade of paper, those 
dyestuffs should be selected which will give the most economical 
match, consistent with the quality to be maintained. In certain 
papers, fastness to (resistance to change by) light is the impor- 
tant qualit}'; while in others, fastness to alum, acid, or alkali may 
be the properties required. Fortunately, the paper industry 
does not have as many fastness tests to which the dyestuffs must 
be subjected as will be found in the textile industries. With a 
few exceptions, fastness to light, acid, alkali, heat, and chlorine 
are the only tests necessarj^ in the selection of dyestuffs for paper. 

60. Fastness to Light. — The first important fact to consider 

in making a test for fastness to light is that all stocks are 

discolored in the sunlight with varying degrees of rapidity; and 

any discoloration that may be due to exposure should be followed 

through, to determine whether the change in color is due to the 

pulp, to the dyestuffs, or to, perhaps, a combination of both. 

Bonds, ledger, cover papers, and wall papers are grades where 

fastness to light is important. These papers are exposed, in the 

course of their use, to varying degrees of sunlight, and a dycstuff 

should be selected whose fastness to light approaches as nearly as 

is possible to the fastness of the pulps from which the paper is 

made. In newsprint, wrapping papers, and cheap grades of book 

' 0.5 g. dye stuff per liter (practically = 1000 g.) = 0.0005 g. per c.c. 
5 c.c. = .0025 g. and .0025 fg. dye per 2.5 g. pulp = 1 g. to 1000 g. or 
1 lb. to 1000 lb. 1 c.c. alum, etc. = .025 g. per 2.5 g. pulp = 10 g. per 
1000 g. or 10 lb. alum, etc. per 1000 lb. pulp. 


and magazine papers, there is never any need to sacrifice cheap- 
ness for fastness properties. Consequently, in all papers where 
groundwood (which discolors rapidly in sunlight and is naturally 
dull in appearance) is used, basic colors should be adopted, 
because of their low cost and extreme brilliance. 

No paper can be colored with organic dyes so it will be 
absolutely fast to sunlight. Certain pigments, chief of which are 
those derived from the vat colors, possess the greatest fastness, 
while the acid, direct, and basic dyestuffs follow in this order. 

61. Tests for Fastness to Light. — There are several ways in 
which fastness-to-light tests can be made. Exposure to direct 
sunlight is the most conclusive test, but it is difficult to obtain 
definite comparative results bj^ this method, because of the 
varying degree of brightness of sunlight at various times of the 
day or year. Laboratory tests may also be made means of a 
fadeometer or an ultra-violet lamp. When comparisons are to be 
made between two different dyestuffs or between two different 
stocks using the same dj^estuff, the several dyeings should be 
exposed to the raj^s of these lamps at the same time; because, 
even in the laboratory, the conditions affecting the heat and 
strength of the rays emitted by the lamps vary to a certain extent. 

For reasons just explained, no numerical values as to the 
comparative fastness of all dj^estuffs is possible. All comparisons 
must be relative; for which reason, it is recommended that 
dj'estuffs be divided into five general groups, when making such . 
tests, rather than to try to classify them in a numerical order 
based on percentages. 

62. Fastness to Alkali. — Fastness to alkali is important in such 
papers as soap wrappers, wall papers, and box cover papers, 
where alkaline pastes are used, or for any type of wrapping 
papers that are liable to come into contact with alkaline materials. 
A spot test, with |% solution of caustic soda or 2% solution of 
soda ash, is sufficient for commercial purposes. Fastness to 
alkali is also necessary' in ledger and bond papers, so they shall 
be fast to chemical erasures. For testing the fastness against 
chemical erasure, laboratory samples of the paper, made with the 
dyestuff material being examined, should be spot-tested. 

63. Fastness to Acids. — For dyestuff tests on fastness to acids, 
colors may be divided into three groups : The first group includes 
those dyestuffs which are unaffected by alum or a 1 % solution of 


sulphuric acid; the second group includes those which are affected 
by alum and sulphuric acid; the third group includes those dye- 
stuffs which are affected by a 1 % solution of sulphuric acid, but 
are not altered by alum. 

All direct dyestuffs are affected in shade by the use of alum 
and by spot tests of sulphuric acid, being dulled to a considerable 
extent. Acid colors as a class are fast to acids, one important 
exception being metanil yellow, which is very sensitive to even a 
slight excess of alum. Basic dj-estuffs as a class are not affected 
by alum; but no general rule applies as to their reactions with 
sulphuric acid. 

64. Fastness to Heat. — No special laboratory tests are possible 
that will determine the effect of heat on finished paper, for 
finished paper is never subjected to heat above a temperature 
harmful to the dyestuff. Nevertheless, the effect of heat on 
various dyestuffs during the process of paper manufacture is an 
important consideration, and a practical knowledge of which dye- 
stuffs are thus affected is essential. When the dryers are some- 
what too hot, certain acid dyestuffs seem to be drawn to the 
surface of the paper, giving a decidedly spott}^ appearance to the 
sheet and a difference in the color of the two sides {tivo-sidedness). 
The uniformity of color throughout the run may be seriously 
affected by variation of temperature of the dryers. Metanil 
yellow behaves worst in this respect, especially in the presence of a 
slight excess of alum. Certain basic and direct dyestuffs give a 
different shade to the paper when it first comes off the machine 
from that which prevails when the sheet is cooled. When such 
dyestuffs are used, allowance for this effect must be made when 

65. Fastness to Chlorine. — In paper manufacture, trouble 
with chlorine is experienced where freshly bleached stock is 
furnished to the beater. In cases where the stock is so poorly 
washed that large excesses of chlorine still remain, an antichlor, 
such as sodium sulphite or sodium thiosulphate, should be added 
to the stock in the beater, to react with the free chlorine. To 
determine the effect of poorly washed stock upon certain dye- 
stuffs, two hand samples should be run in the laboratory, to one 
of which should be added a dilute solution of bleaching powder. 
It should be remembered that the use of antichlor usually 
leaves the stock acid. 


66. Tests Should Be Comparable.— The above-described tests 
should be made as compai'able to the actual working conditions 
in the mill as is possible. Where time permits, the dyestuff 
manufacturer will give information as to the reactions of the 
dyestuff with various chemicals. In other cases, special tests 
should be made by the above methods, using actual mill stocks 
and mill solutions, in order to get the best practical results. 

67. Effect of Fillers. — All fillers used in the process of paper 
manufacture have a certain absorptive power for dyestuffs, the 
degree of absorption depending on the nature of the filler and also 
on the relative affinity of the dyestuffs for the pulps and fillers. 
When the fillers are added to the beater in the presence of dye- 
stuffs, a state of equilibrium is established between the amount 
of dyestuff absorbed by the fillers and that retained by the pulp. 
Since some of the filler is lost in the backwaters, there is a cor- 
responding loss in available dyestuff. Concrete information 
concerning relative absorptive powers of various fillers for indi- 
vidual dyestuffs would benefit the paper maker. Research work 
on this subject has been started, and the results obtained will be 
submitted to the paper industry as a Report of the Committee 
on Dvestuffs. 


68. Matching Shades. — Matching shades in the laboratory, 
together with subsequent work in the mill, is dependent on the 
character of the stocks, chemical furnish, finish and the class of 
dyestuff to be used, as well as on the training of the eye to detect 
readily slight differences in strength and shade. The pulp and 
chemical furnish is usually given to the laboratory for the 
sample of paper to be matched. If not, a microscopic analysis 
will determine the percentage of various pulps in the furnish; 
and approximate tests for sizing and loading will determine the 
proportions of size, alum, and fillers necessary. If the paper 
sample to be matched be heavily calendered, it should be steamed 
for a few minutes, to graduate the finish to approximately that 
of the laboratory hand samples, so the true color of the paper 
sample can be noted. If the sheet be water finished, allowance 
must be made for the darkening of the sheet by this treatment. 
In matching samples of glassine paper, satisfactory results can 
be obtained only when the highly hydrated pulp used in the 


manufacture of this type of paper is obtained from the mill 
beater; for it is impossible to hydrate stock to that degree in a 
miniature beater. For a given shade, approximately one-half the 
amount of dyestuff is required for glassine papers that is necessary 
for the ordinary drj'-finished sheets. 

69. When matching am^ new shades, it is advisable to do the 
work by daylight, a north light being preferable to any other for 
this purpose. The various daylight lamps on the market are 
valuable for matching shades when such work cannot be done 
in the daytime; but the change of shade of different dyestuffs 
under artificial light will not hold constant under any daylight 
lamp at present available. 

The general method for preparing hand samples from various 
stocks and with various chemicals has been previously discussed. 
When matching shades in the laboratory, the same methods 
apply as when testing for strength and shade of an individual 
dyestuff, except that a combination of colors is used to match 
the given sample. 

70. Matching Dyestuffs. — To save time in making laboratory 
matches, the following procedure should be adhered to in order 
to approximate the quantity of dyestuffs required to obtain a 
given shade. After the dj^estuff, size, and alum have been added 
to the stock in a porcelain-lined cup, a small amount of the stock 
should be taken from the cup, squeezed between the thumb and 
forefinger, and placed on a hot-plate to dry. On comparison 
with the given sample, an approximation can be made. A 
small test sample of this kind should be taken out following the 
addition of each new furnishing of dyestuff; for, in this way, a 
close approximation can be reached with one weighing of stock, 
and time is saved in making finished hand samples. When 
matching a shade where the quantities of each dyestuff are being 
varied slightly, care should be taken not only to measure out the 
dyestuff accurately but also to watch carefully the order of the 
addition of color, size, and alum and the length of time of 

71. Amount of Dyestuff to Use. — By using the methods 
described in the last article, the quantity of dyestuff necessary 
per 1000 pounds of stock can easily be calculated. Experience 
has shown that, as a rule, the amount of dj^estuff required to 
match a sample in the laboratory is usually in excess of that 


actually required in the mill. For this reason, it is recommended 
that, in all cases where a laboratory formula is to be used in the 
mill, the first addition of dyestuff to the beater should be only 
75% of that called for by the laboratory formula. 

72. Cost Comparisons. — The determination of the actual 
color value of a dyestuff is not always a simple problem. This is 
due to three facts: first, it is very easy to reduce a particular 
dyestuff 5% or 10%, in order to meet price competition; but this 
reduction may not be observed by the paper manufacturer, due 
to variations in pulps or in mill conditions. Second, in certain 
grades of paper, it is difficult to estimate the depth of a shade 
within an accuracy of 10%; this is particularly true in the case of 
yellow shades on all papers, and to all shades on the cheaper 
grades of wrapping papers and boxboards. Third, while it is 
comparatively simple to compare two dyestuffs of the same 
constitution, such as two methyl violets or two methylene blues, 
it is difficult for the manufacturer to obtain the actual color 
value when deciding between a low-cost dye of comparatively 
poor fastness qualities and a higher-price dye of superior qualities. 
This problem resolves itself into a broad study of what the con- 
sumer of the paper actually wants, and to conditions of eflftciency 
in the manipulation of dyestuffs throughout the process of 
manufacture. It is worth while, however, to make a laboratory 
comparison of dyestuffs, and, from the percentages required to 
give matched samples, to calculate from the price of the dyestuffs, 
the money value of each in the paper. 



73. Methods of Coloring. — The methods employed in the 
coloring of paper may be divided into several classes; namely, 
beater coloring, calender coloring, combination of beater and 
calender coloring, tub coloring, dipping, specialty coloring by 
special processes, and coloring of coated papers. Approximately 
95% of the coloring of paper is done in the beater; for which 
reason, the greater part of the remainder of this Section will be 
devoted to that branch. 


74. Color Room Essential. — A well-equipped color room is 
essential, regardless of the process by which the paper is colored. 
While slight variations in equipment are necessary in mills 
doing other than beater coloring, such variations must depend 
on mill conditions, and they will not be discussed in detail at this 

Every beater room should have an adjoining color room, to be 
used for the storage of all kegs and barrels, and for the weighing 
and dissolving of all dyestuffs. This color room should have a 
cement floor with two drains; one drain approximately in the 
center of the room, the other beneath the outlet of a hot-water 
storage tank. Shelves should be built along one side of the 
room, for the storage of tins and small containers, and the room 
should have a wall table, on which the balances are placed. 

75. Equipment of Color Room. — A well-equipped color room 
should contain one rough balance, having a capacity of 20 pounds, 
weighing to ounces, and a finer balance, having a range from ^j 
ounce to 2 pounds. The accuracy of these balances should be 
tested at regular intervals. The authors recommend the ordi- 
nary type of computing grocery scale, with a glass top, as best 
suited to this work. 

76. Hot-Water Storage Tank. — A hot-water storage tank, 
having a capacity of from 50 to 100 gallons, capable of furnishing 
a constant supply of hot water at a temperature just below 
boiling, should be available. The best type is equipped with a 
thermostatic control, which is connected to a steam pipe in such 
a manner that, when the temperature falls below 200°F., steam 
will automatically be injected into the tank until the temperature 
is raised to the desired point, when the steam is shut off. 

77. Barrels and Other Containers. — In most cases, the barrels 
and larger containers are left standing on the floor of the color 
room. To insure that the dyestuffs are kept dry, it is recom- 
mended that a platform be built 2 or 3 inches above the floor, 
on which to place the barrels. A still better plan is to arrange 
bins, similar to flour bins, into which the ordinary size barrel 
will fit; such an arrangement insures a dust-proof storage space 
in the color room for dyestuffs. If the barrels or kegs of dyestuffs 
are left open on the floor, the names of the dyestuffs should be 
stenciled on their sides. It has been the practice of dyestuffs 
manufacturers to label their containers on the covers. Upon 


removing the covers in the color room, they often become mis- 
placed by being set on the wrong barrels. In their powdered 
form, many aniline dyestuffs have a similar appearance under 
artificial light; hence, unless the barrels are thoroughly marked 
on the sides, mistakes are liable to occur that may prove serious. 
Copper-lined containers, ranging in capacity from 10 to 25 
gallons, are the best for dissolving dyestuffs; but galvanized-iron 
pails and wooden half-barrels are used extensively^ for this 
purpose. Wooden containers, however, have the disadvantage 
of soaking up a limited amount of the dyestuff when first used, 
and they are more difficult to clean. Plain iron containers must 
never be used. LTpon emptying the containers, they should be 
thoroughh' cleaned, turned upside down to dry, and thus left in 
condition for further use. 

78. Dissolving Dyestuffs. — The following is the proper method 
for dissolving dyestuffs: Fill the container with hot water from 
the storage tank; sprinkle in the dyestuff very slowly with one 
hand while stirring with the other, the stirring being continued 
until all the dyestuff is dissolved. After the solution is complete, 
cold water should be added as a safeguard, to prevent the forma- 
tion of granite fibers on mixed furnishes, which often occurs when 
the dyestuff solution is added to the beater in a too-hot condition. 
The quantity of water required depends upon the individual 
dyestuff. The best general rule to follow is to use a minimum of 
40 parts of water to each one part of basic dyestuff. The solu- 
bility of some basic dyestuffs is increased by the use of acetic 
acid, in which case, the best results are obtained bj' mixing an 
equal weight of the acid with the basic dyestuff and adding the 
hot water to the mixture, with constant stirring. Hard water 
has the property of precipitating all basic dyestuffs and certain 
direct dyestuffs. Whenever it is necessary to use hard water for 
dissolving dyestuffs, a small amount of acetic acid should be 
added to the dissolving water, to compensate for the temporary 

79. Solution Storage Tanks. — In mills where a single grade 
of paper is run continuously, such as newsprint, it is advantageous 
to have large mixing and storage tanks for the dj^estuff solutions. 
The best type for this purpose is a cj-lindrical wooden tank con- 
taining a paddle agitator, the size depending on the production 
of the mill. When storage tanks are used, solutions of basic 


dyestuffs should never be made up more than 24 hours in 
advance; for, after a period of time, the strength of the dyestuff 
increases. However, acid and direct dyestuffs can be stored in 
such tanks for several daj'^s. 

80. Beater-Room Equipment. — In addition to that previouslj^ 
mentioned, the equipment necessary for efficient beater coloring 
includes a small truck, hand mold, hot plate, sieve, or strainer, 
and various volumetric measures, such as pint, quart, and two- 
quart dippers. 

The container that is used for dissolving the dyestuff can be 
kept on the truck, for conveying the color from the color room 
to the different beaters. A small hand mold, from 2 to 3 inches 
in diameter, is used to make hand samples of the stock from the 
beaters while the initial formula is being built up. If a hot-plate 
(electric or steam) be used to dry out such samples, the time that 
would otherwise be lost in running back and forth to and from 
the machine room to dry the samples on the paper machine is 
saved; also, in some cases, such as starting up Monday morning, 
the dryers may not be hot enough to dry the samples satis- 
factorily, and further time is lost. The initial small cost of the 
hot-plate will be more than compensated for b}^ the satisfactory 
service obtained from it. 



81. Why Shades Vary.— The shade produced by a dyestuff 
on different stocks varies between wide limits. With basic 
colors, stock containing a certain percentage of tannin-like or 
lignaceous material will be colored a much deeper and duller 
shade than stocks that have been partly or wholly bleached, 
since the bleaching process removes this material. For example, 
stocks such as unbleached wood pulps, jute, etc. contain sufficient 
lignaceous material to combine with all the dyestuff, leaving the 
back waters perfectly clear. Likewise, pulps obtained from 
different cooks in the same mill will often vary between 25% 
limits in the amount of dyestuff required to produce a given 
shade. In other words, a very hard or raw cook requires less dj-e- 
stuff to produce a given shade than a soft cook does. Although 


groundwood contains a higher percentage of Hgnaceous material 
than unbleached sulphite, the lignaceous material in ground- 
wood is not in an as activel}^ combinable state as in unbleached 
sulphite; it is for this reason that a granite effect or hairy- 
fibers are produced in mixed furnishes that contain unbleached 
sulphite and ground wood. 

82. Action of Basic Dyestuffs on Rag Stock. — Rag stock has 
very little affinity for basic dyestuffs. When using basic dye- 
stuffs on such stock, a certain proportion of the dyestuff com- 
bines with the fibers, and a certain additional amount is held on 
the fibers by the size and alum; but the back waters can never 
be cleared up. 

83. Action of Acid Dyestuffs. — Since acid dyestuffs have no 
direct affinity for any type of cellulose fibers, being mordanted 
to the fibers by the use of size and alum, thej'- can be used on all 
types of stock with equal success, and will give the most even 
dyeings on mixed furnishes. 

84. Action of Direct Dyestuffs. — As before stated, direct (or 
substantive) d^-estuffs are named from the fact that they have a 
direct affinity for cellulose fibers. The greater the degree of 
purity of the fiber the greater is its combining power with direct 
dyestufi's; for which reason, they color most efficiently the 
bleached rag and wood pulps. Owing to the fact that the 
cellulose fiber in groundwood is surrounded by other material, 
the direct dj-estuffs have little affinity for this type of stock; 
and, in some cases, where the groundwood is coarse, they leave 
uncolored shives in the paper. 


85. Use of Mordants. — A mordant combines with a dyestuff 
on or within the fiber, to form an insoluble compound; in other 
words, it fixes the dye. The paper industry does not use mor- 
dants to as great an extent as the textile and other dye-consuming 
industries, because no material that will interfere with the 
sizing of the sheet may be added in the manufacture of paper. 
The size and alum act as a mordant for certain dyestuffs, the 
degree of mordanting depending on the kind of pulp, method of 
beating, and the properties of the dyestuff. 


86. Coloring Unsized Papers. — Because of the affinity of 
direct dyostuffs for cellulose fibers, they can be used satisfactorily^ 
on unsized paper, such as blotting papers. For heavy shades, 
however, the addition of 40 or 50 pounds of salt to the beater 
gives a greater depth of shade and clearer back waters. The 
action of salt in this case, however, is not that of a mordant — it 
acts as a "salting out" agent. 

In a beater containing cellulose fibers, together with a certain 
amount of water holding a dj'estuff in solution, if a more soluble 
salt be added to the beater, it will tend to drive a less soluble salt 
of the same base out of solution. The addition of salt tends to 
throw the dyestuff out of solution; but, on account of the 
affinity of the cellulose fibers for this dyestuff, the dj'-estuff is 
forced onto the fibers, instead of being crystallized out of the 
solution. Most dyeings with direct colors are brighter on unsized 
than on sized papers, because the sodium salt of the dyestuff is 
much brighter than the aluminum salt that is formed when alum 
is added to the beaters. 

87. Action of Size and Alum. — Acid colors are mordanted to 
the fibers, in all cases, by the use of size and alum. While the 
presence of an excess of alum increases the retention of the color 
on the fibers, better results can be obtained by increasing both 
size and alum in proper proportions rather than by having an 
excess of alum only. The fact that heavier sizing increases the 
shade produced by acid dyestuff s, warrants the assumption that 
the greater the quantitj^ of size the larger the number of particles 
there are to which the color may become attached, or by which 
it may become trapped in the fibers. Pigment colors behave 
in a manner similar to acid colors in this respect, far better results 
being obtained on the heavier sized than on the lightly sized 

88. Action of Soda Ash, Borax, and Other Chemicals. — 

When soda ash is used with certain direct dyestuffs, such as the 
various brands of purpurines and Congo reds, or borax is used 
with such acid dyestuffs as metanil yellow, it does not act as 
a mordant; it here serves to neutralize any excess of alum that 
has been added to size the paper, in cases where alum has a 
deleterious effect on the shade of the dyestuff. 

89. To a limited degree, other chemicals are used as mordants 
for specific dyestuffs. When certain direct colors are treated 


with copper sulphate, their fastness to Hght is greatly increased; 
two parts of copper sulphate should be used for every one part 
of such direct dyestuffs. Lead acetate decidedh^ improves the 
brightness and fastness of such phthalic anhydride dyestuffs 
as eosine, phloxine, and erj^throsine. 

90. The use of tannic acid, or other tannin-like materials, 
decidedly mordants basic dyestuffs to the various fibers. The 
reason their use has not been more completely developed in the 
paper industry is because iron has the property of darkening 
tannin; hence, trouble is experienced on account of this darkening 
action, and the paper is streaked where it comes into contact 
with iron. 

91. After-Treatment with a Mordant. — There is no doubt 
but that after-treatment of the colored stock with the proper 
mordant would, in mam- cases, improve the fastness to light, 
two-sidedness (see Art. 106), and would clear up the back waters. 
A large amount of work is still to be done in connection with this 
subject before a comprehensive knowledge of proper methods for 
coloring paper is obtained. 


92. Relation of Coloring to Furnish.— The order of furnish was 
discussed in the Sections on Beating and Refining and in Loading 
and Engine Sizing but it is well again to consider it here in 
connection with the subject of coloring, because it bears an 
important relation to this subject. It must be borne in mind, 
however, that the methods emploj-ed for coloring paper are 
necessarily subordinate to those employed to obtain the maxi- 
mum production of paper of the quality desired, using the equip- 
ment at hand. This accounts for the fact that, in many mills, 
efficient coloring methods are sacrificed for quantity production. 
A thorough understanding of all the factors affecting production 
will be of assistance in working out methods that will give the 
most satisfactory results under existing mill conditions. 

93. Opinions Regarding Order of Furnish. — Opinions differ as 
to the proper order of addition (furnish) of stocks, d^-estuffs, size, 
alum, fillers, etc. to the beater; this is natural, because of the 
varying water and stock conditions at different mills. In cheaper 
grades of paper, differences in the quality of the sheet that arise 


from failure to follow the best methods of furnishing are less 
noticeable than in the higher grades, which are subjected to more 
rigid tests, both as regards their physical properties and their 
appearance. This matter will here be first discussed on the 
assumption that the stock furnished is of one tj^pe. 

94. Stock All of One Type. — With soft water, basic dyestuffs 
should be added before the size and ahmi. If the water is com- 
paratively hard, the dyestuff should be added after the size and 
alum ; or, a small quantity of the alum, sufficient to neutralize the 
hardness, should be added before the dyestuff, followed by the 
size and the remainder of the alum. 

With acid dyestuffs, the order depends upon the amount of 
excess alum used in the paper ; if only sufficient alum be used to 
precipitate the size, then no difference will be perceived between 
adding the dyestuff before or after the size and alum; but, if an 
excess of alum be used in the beater, better results will be obtained 
by adding the dyestuff after the size and alum. 

Direct dyestuffs should always be added to the beater before 
the size and alum; because, on account of having a direct affinity 
for cellulose fibers, the direct dyestuff should be allowed to come 
into contact with the fiber before it is coated with size and alum. 

Where color formulas are built up that contain basic and either 
acid or direct dyestuffs, the acid or direct dyestuffs should be 
added to the beater and thoroughly mixed with the stock before 
the addition of the basic color solution. Where both acid and 
direct colors are used, they can be dissolved together; but if they 
are dissolved separately, the solution of direct dyestuffs should be 
added before that of the acid dyestuffs. 

95. A General Rule. — A general rule for the addition of all 
chemicals, such as copper sulphate, lead acetate, etc., is to add 
them directly after the dyestuff and before the size and alum; 
salt should also be added immediately after the dyestuff. But, 
when soda ash is used, it is an open question as to whether or not 
it should be added before or after the size and alum. (The 
authors, personally, do not believe in the use of soda ash, for the 
good it does is more than offset by its deleterious effects.) When 
soda ash is added after the size and alum, it tends to dissociate 
the aluminum resinate, and, at the same time, to replace the 
aluminum radical in the dyestuff with the sodium radical. Con- 
tinued beating tends to increase these two reactions, with the 


result that the degree of sizing and the comparative brightness 
in shade will depend upon the length of time of beating. 

96. Mixed Furnishes. — When mixed furnishes are used, very 
careful attention must be paid to the order and method of adding 
the dyestuffs, to prevent mottling. With basic colors on a 
mixed furnish of groundwood and unbleached sulphite, the 
groundwood should always be furnished to the beater first, 
followed by a cold solution of dyestuff, unbleached sulphite, size, 
and alum, in the order here given. On mixed furnishes contain- 
ing wood pulp and rag stock, direct colors, when used, should 
always be added to the beater in a cold dilute solution. On 
account of the nature of the fiber, rag stock is always furnished 
to the beater before the wood pulp; consequently, it is out of the 
question to consider reversing this order, for the sake of obtaining 
a more efficient color practice at a decided sacrifice of beater prac- 
tice. In order to prevent mottling on such mixed furnishes con- 
taining rag stock, where direct dyestuffs are used, it is sometimes 
recommended that these dyestuffs be added to the beater in a dry 
state as soon as the beater is furnished. 

97. Adding Dyestuffs in Dry State. — In many cases, mill 
practice has designated that the dyestuffs be added to the beater 
in a dry state; but such practice is bound to result in a slight 
increase in the dirt content of the paper. Although the dye- 
stuffs of reputable manufacturers are very clean, it is impossible, 
in the case of any commodity that must be ground and packed, 
to keep a ver}^ small amount of insoluble matter from becoming 
mixed with the dyestuff. In the cheaper grades of paper, the 
amount of dirt or dust from the dyestuff will be inappreciable, as 
compared with the actual dirt in the pulp; but, in the higher 
grade rag papers, this small amount may be perceptible at times. 
For the above reasons, the best general mill rule is to dissolve 
and strain all dyestuffs. 

98. An Important Point. — The most important point to 
remember in connection with the whole subject of order of furnish 
is that, once a furnish and formula have become established, 
every beater making that order must be handled in exactly the 
same manner. 

99. Influence of Density. — The density of the stock in the 
beater, which varies between 2.5% and 8% (depending on the 
nature of the stock and the type of the beater), has a very 


decided effect on the coloring power of certain dyestuffs. As a 
general rule, the greater the density of the stock in the beater the 
greater the depth of shade obtained with a given quantity of dye- 
stuff. This is explained by the fact that thorough brushing out 
of the fibers has a tendency to work the dyestuff into the fibers 
of all stocks that have a direct afl^inity for the dyestuff. In 
the case of acid dyestuffs, the mordanting action of the size and 
alum on the dj^estuff is proportionately increased with the 


100. Building Up Color Formulas. — Every beater engineer has 
his own individual ideas concerning the best methods for building 
up color formulas; this is due to the fact that conditions in each 
mill are different, both in regard to equipment and to furnish. 
Before deciding upon any definite plan of procedure, the beater 
engineer must have a real appreciation of the many variables that 
influence the shade before the pulp comes off the machine as 
colored paper. The factors that must be taken into consider- 
ation are : the consistency^ (or density) of the stock in the beater, 
method of beating, type of dj^estuff used, the effect of chemicals 
present, action of colored stock in chests, loss in backwater, color 
taken up bjj^ felts, action of heat of dryers, and finish of the paper. 

101. Factors to be Considered. — When the order first goes into 
the mill to make a certain grade and shade of paper, the super- 
intendent or beater engineer compares the shade with that of 
samples from previous runs. If a run has been made that closely 
approximates this shade, he can start coloring his beater with a 
formula approximately 20% less than the one used on his previous 
run. Consideration must be given at this point to the matter of 
amount and shade of broke that may be included in the furnish. 
On re-pulping broke in the beater, it loses a part of its color 
strength, the amount lost depending on the class of dyestuff or 
pigment used in coloring it. Colored broke should be distributed 
to all the beaters, not all dumped into one. Allowance must be 
made for the percentage of broke in the furnish and the pro- 
portion of coloring strength retained. Precaution should alwaj^s 
be taken to see that too much dyestuff be not added at the start ; it 
is far easier to add color to the beater than it is to correct for 
shade when the strength is too high. The dyestuff, whether in 


the form of dry powder or in water solution, should not all be 
dumped in at one spot in the beater, but should be allowed to 
flow in gradually during one complete revolution of the stock in 
the beater, thus giving the color a more even distribution. 

102. Use of Laboratory Matches. — In case the beater engineer 
has no guide to follow from previous runs, he must depend upon his 
laboratory match to approximate the initial amount of dyestuff 
he should add to the beater. In case the mill be not equipped 
with laboratory apparatus for matching shades, a sample should 
previously have been sent to the laboratory of one of the dye- 
stuff manufacturers, to obtain an approximate formula. It is 
much better to work from a formula with individual colors in the 
mill than to have a sample matched by a color house and a 
mixture of dyestuffs sent to the mill. In the first instance if there 
is any variation in the stock, water, or chemicals, this difference 
can be more easily overcome by the use of one or more of the 
component colors; whereas if the mixture is used, the shade can 
be varied in depth only. As stated in Art. 71, all laboratory 
matches are approximations; they serve their purpose by acting 
as guides in building up formulas in the mill. These laboratory 
matches should be cut approximately 25 % (Art. 70), and then 
built up with one dyestuff or another, in order to obtain the 
correct shade. 

Some color men, however, prefer to get their main shade by 
using a mixed dyestuff, and to give this any final variation 
necessary to compensate for the factors mentioned by adding 
more of one or the other of the component dyestuffs. 

103. Matching Shades in the Beater. — After the pulps, color, 
size and alum have been beaten for a certain length of time, the 
shade of the stock in the beater should be compared with a 
small wet portion of the sample to be matched. Also, a hand 
sample, as previously explained, should be taken from the 
beater and dried, and compared with the sample to be matched. 
Only continued practice in the matching of shades in the beater 
will give the beater engineer a knowledge of just how a shade that 
has been brought up to a certain point in the beater will work on 
the paper machine. 

That the first few pounds of paper coming over the machine 
may be of the same shade as that later in the run, it is sometimes 
necessary to color up the white water, and also to add a small 


amouut of dyestuff to the fan pump, to compensate for the color 
built up in the return waters later in the run, and for the color 
absorbed by the felts. This method should never be relied on 
unless the beater engineer has had considerable experience in 
making such additions; a limited experience may cause far more 
trouble than the good to be derived. 

104. Doctoring the Shade. — As soon as the sheet that is 
representative of the stock in the chests comes over the paper 
machine, a comparison with the sample to be matched will show 
whether the shade is correct or whether certain additions will 
have to be made. There are two methods of making these 
additions: first, coloring the chest; second, adding an extra 
amount of dyestuff to the second beater to compensate for the 
shortage of dyestuff in the first one dropped. Coloring the chest 
is a difficult process to regulate; it should be avoided whenever 
possible, because such coloring has a tendency to make the shade 
run uneven. However, if this procedure be necessary, the 
amount of stock in the chests is estimated, the requisite amount 
of dyestuff is dissolved in a very dilute solution, and this solution 
is slowly added, either in the head box of the Jordan or directly 
into the chest. 

The second method, that of dropping a beater with sufficient 
dyestuff to compensate for the difference in shade of the first 
beater, is very satisfactory, provided there is proper agitation 
in the stuff chests. In any mill making colored papers, it is 
absolutely necessary to have good agitation in the chests; other- 
wise, more harm than good is done by trying to regulate the 
shade by coloring the chest or by dropping the second beater. 
Further changes should not be made too rapidly after color or 
additional stock has been added to the chest, because from 15 to 
30 minutes is necessary to obtain the true value of these changes 
over the average paper machine. 

The second beater on the floor, before the paper first comes 
over the machine, should always contain a little less dyestuff 
than the first beater; for, in case the shade may come a little too 
heavy, the second beater can be dropped, which will compensate 
for the increase in shade for the first paper over the machine as 
compared with the sample submitted. After the shade is once 
established on the machine, samples of the finished paper should 
be compared at frequent intervals, particularly, if there be any 
change with respect to the basis weight or finish of the paper, or 


in the amount of suction on either the suction roll or boxes; and 
the wet stock of each beater on the floor should be matched 
against the stock in the stuff chests. 

105. Taking Samples from the Paper Machine.— Insofar as 
the writer's information goes, the taking of samples from the 
paper machine for the purpose of comparing the uniformity of 
the run in regard to color, has not, up to the present time, been 
done as well as it might have been. The uniformity of a color 
run is most effective]}^ observed in the finishing room of the mill, 
where the whole run is at hand. To imitate this condition in the 
beater room while making the paper, two methods may be used : 

(a) A board may be attached to the wall, on which is a row of 
nails. With this may be used a flat piece of tin, of trapezoidal 
shape, for cutting out samples of paper, the samples being cut 
out with this tin as they are taken from the machine. Order 
number, date, and serial number (as 1, 2, 3, and 4) or reel number 
may be attached to each sample as it is taken; and the samples 
are hung up on the board on the wall in the same sequence as they 
were taken from the machine. 

(6) A second method, similar to the preceding, is to use a tin 
plate of rectangular shape, measuring about 3 by 8 inches, for 
cutting out samples as taken from the machine. As before, the 
samples are marked with the order number, date, and serial or 
reel number; but, instead of hanging them on a board, they are 
kept in a loose-leaf folder. 

By either method, the samples may be kept indefinitely; and 
any irregularities that occur during the run of the paper may be 
noted on the samples, as well as their cause. This will serve as 
an explanation, if such be asked for after a long interval, when 
the details of the run may have been forgotten or recollection 
may be hazy. The samples are also useful in the finishing room, as 
they enable the boss finisher to see at a glance whether all rolls can 
be cut together ; or, if a non-uniformity exists, he may select from 
these samples the rolls that are to be cut together on the cutter. 

106. Two-Sidedness. — One of the most important problems 
in the present day manufacture of paper is the matter of two- 
sidedness, by which is meant difference in shade or texture 
between the top and bottom of the sheet. The degree of two- 
sidedness depends on the type of couch roll used, the number of 
suction boxes, the freeness of the stock, the amount of water 


carried and the selection of the dyestuffs. A Hmited amount 
of two-sidedness is absolutely unavoidable on machines where a 
suction couch roll is employed. This trouble is caused by the 
fact that a certain proportion of the dyestuff used to obtain any 
shade is merely mechanically fixed, either to the fiber itself or, 
as in the case of acid dyestuffs, to the size and alum; hence, as the 
paper is formed on the wire and passed over the suction boxes 
and suction roll, a certain amount of this mechanically fixed 
color will be drawn from the bottom side of the sheet. Less 
trouble in this respect will be experienced with a free stock than 
with a slow stock. 

In considering this problem, it is obvious that the extent to 
which two-sidedness can be minimized depends on the selection 
of dyestuffs that will have the greatest degree of adherence to 
the fibers. The degrees of affinity of different classes of dye- 
stuffs for different stocks has already been discussed. On 
unbleached pulpS; with basic colors, very little trouble is experi- 
enced with two-sidedness, because of the direct affinity of the 
basic dyestuffs themselves for the lignaceous material in the 
unbleached pulps. On bleached wood pulps and rag stocks, 
direct colors will give a minimum of two-sidedness, because these 
colors combine directly with the fiber. 

107. Combinations of Dyestuffs. — When selecting combi- 
nations of dyestuffs for any given shade, those should be selected 
which have the same degree of affinity for the various stocks that 
are used in the furnish, in order to prevent different shades of 
color on the two sides of the sheet. Because of the fact that 
pigment colors are mechanically fixed within the sheet, the 
two-sidedness obtained by the use of pigments is far greater than 
that obtained with the aniline dyestuffs. An exception is in the 
use of certain pigments made from anihne dyestuffs, which, due 
to admixture with certain chemicals in their process of manu- 
facture, more or less mordant such colors to the paper fibers; 
hence, they have less two-sidedness than many of the anihne 
dyestuffs themselves. By proper methods of sizing, in other 
words, by the thorough admixture of the size with the stock 
before the addition of alum (preferably added in a dilute 
solution), the two-sided effect will be greatly decreased. 

108. Effect of Heat. — No general rules apply to the effect of 
heat on the various groups of dyestuffs. As before stated, in 


connection with the dissolving of dyestuffs, Art. 11, no basic 
colors should ever be heated to the boiling point. In certain 
cases, for example, auramine and basic or Bismark browns, a 
temperature limit of 160°F. for the dissolving water should be 
adhered to. After the dyestuff has been placed in the beater, 
no trouble will be experienced from the effect of heat on any 
color, provided the temperature is not raised above the point 
that will affect the sizing. On the paper machine, certain 
dyestuffs have the property of changing in shade, due to the 
heat of the dryers. The manner in which they change is entirely 
individual with different dyestuffs. Chrysoidines and basic 
browns in sized papers have a tendency to be redder when they 
first come off the machine than they are after the paper has 
assumed a temperature and moisture content conforming to 
atmospheric conditions. Certain acid colors have a tendency 
to burn on the surface of the sheet. In some cases, if the dryers 
are too hot, this burning will be very spotted, and it will practi- 
cally spoil the sheet. Dyestuffs that have a tendency to spot 
should be avoided. 

With acid dyestuffs, in many cases, the color itself is very much 
stronger on the surface than in the middle of the sheet ; this is not 
a disadvantage, except in very heavy papers, such as cover papers. 
In cases of direct colors, the increase or difference in shade caused by 
the heat of the dryers is lost as soon as the paper is in equilibrium 
with atmospheric conditions. For this reason, when matching 
shades with direct colors, it is a good policy to take a sample 
taken from the machine and wave it in the air for 4 or 5 minutes, 
(to cool it) before comparing with the sample to be matched. 

109. Effect of Finish. — The degree and type of finish given 
the paper has a decided effect on the depth of shade obtained with 
a given quantity of dyestuff. The more highly calendered the 
sheet the greater will be the depth of shade ; in other words, with 
a given quantity of dyestuff, a supercalendered sheet will have 
the appearance of being much more heavily dyed than a machine- 
finished sheet. Water-finished papers have the appearance of 
greatest depth, as compared with any other type of finish. As 
stated before, when matching the highly finished sheets, it is 
necessary to steam them before comparing with unfinished 
samples coming off the machine. For color comparison, samples 
should be taken, whenever possible, from the run, before the 
paper goes through the calenders. 


110. Beater-Room Practice. — The general rules that must be 
followed to obtain efficient beater-room practice vary with 
different mills, on account of the existing conditions as to equip- 
ment and materials. From what has been previously stated, a 
general idea of efficient operation, as applied to each particular 
manufacturer, may be obtained. Attention is called to the 
following points because of their application to anj^ situation: 

All vessels in which dyestuffs are dissolved should be 
thoroughly cleaned as soon as they have been used. Except in 
certain special cases, dj^estuffs should always be dissolved at 
temperatures just below the boiling point of water, and they 
should be strained before adding to the beater. During the 
process of packing, as well as when opening kegs or barrels at 
the mill, small quantities of dirt and insoluble matter are liable 
to become mixed with the dyestuff; hence, it is a good general 
rule always to strain the dyestuff solution. Strainers should be 
kept scrupulously clean and should be inspected frequently for 
an}' damage. 

When once a formula has been adopted, it is most essential 
that the order of addition of different dyestuffs, size, alum, fillers, 
etc. be strictly adhered to. Samples of all runs, with formulas 
attached, should be kept bj^ the beater engineer; and, on each 
sample, all notations regarding speed of machine, basis weight, 
conditions of stock, etc. should be tabulated, so that in case 
another run is made that requires changing the formula, an 
explanation may be obtained as to the cause of such change. 


111. Calender Coloring. — Calender coloring comes next in 
importance to coloring in the beaters. This process resembles 
staining rather than actual dyeing; in fact, it is virtually a water 
finish, in which a color solution is used instead of water only. 
In calender coloring, the dj^estuff solution is allowed to flow 
constantly into one or more water or color boxes on the calenders, 
this solution being picked up through the rapidly revolving 
calender rolls and applied to the surface of the paper as it passes 
between these rolls. 

112. Low Cost. — The principal advantage of calender coloring 
is its low cost. Acid dyestuffs are most commonly used for 


this purpose because of their generally good solubility, and 
because, having no direct affinity for cellulose fibers, the shade 
produced runs more uniform than with any other class of dye- 
stuffs. Acid dyestuffs are also more stable to continued temper- 
atures up to the boiling point, which sometimes makes their 
use advantageous in this type of coloring. 

113. Calender Coloring with Basic and Direct Dyestuffs. — 
Basic dyestuffs are sometimes used in calender coloring in those 
cases where extreme brightness and minimum cost are more 
important than uniformity of shade. The basic dyestuffs have 
a tendency to mottle and streak the finished paper, and to 
deteriorate in strength upon standing in the hot solution. The 
direct colors are also used occasionally for calender coloring; but 
these also have a tendency to streak the paper, and they have 
neither the advantage of cost nor brightness over the acid 

114. Apparatus Employed. — The apparatus for calender color- 
ing consists of: a tank, or barrel, for dissolving the dyestuff, 
into which runs the overflow from the water boxes; a solution 
storage tank,- which is set on a platform at a height above the 
top of the calender stack, from which the pipe to the water 
boxes is led; a circulating pump, for the purpose of transferring 
the solution from the dissolving or overflow tank to the storage 
tank. The strength of the dyestuff solution is determined by the 
shade required. In cases where the shades are produced by 
combinations of dyestuffs, concentrated solutions of the indi- 
vidual dyestuffs should be made up and mixed together in the 
dissolving tank until the proper shade is obtained; they should 
then be diluted to the proper strength, either in the dissolving 
tank or in the storage tank. The water boxes are made with 
one side, two ends and a bottom. The ends are shaped to fit 
closely the calender roll against which they fit, and leakage is 
prevented by rubber packing at the ends and a rubber lip on 
the edge of the bottom. The box is set against the upward 
turning side of the roll. 

115. Formulas for Calender Coloring. — The following proced- 
ure is recommended for working out calender-coloring formulas 
before the actual run is started. A time is selected when the 
paper going over the machine approximates the furnish of the 
paper to be colored. The water box is dammed back several 


inches from the edge of the sheet, and the color solution, which 
is being made up in the dissolving tank, is poured onto the face 
of the calender roll, where the sheet is running dry. This gives 
the same effect as will be obtained when the color solution is 
used in the w^ater boxes; consequently, by changing the strength 
of the solution and the relative proportions of dyestuff in the 
dissolving tank, the proper formula can be worked out. 

As soon as the run is started, the color solution flows from the 
storage tank into the water boxes, on either or both sides of the 
sheet, in the same manner as water is applied for the regular water 
finish. When only one side of the paper is to be colored, water 
must be run into the water boxes on the opposite side of the sheet, 
in order to get an even finish and to counteract curling. 

116. Efficiency of Calender Coloring. — The degree of efficiency 
of calender coloring depends largely upon the manipulation of the 
paper before it reaches the calenders. The degree of sizing also 
has a decided effect on the results obtained. If the paper is 
slack sized, the dyestuff solution will penetrate deepl}^ through 
the surface, giving a greater depth of shade than is the case with 
a hard-sized sheet; it will also make the paper feel damp, and 
it will be without snap. With a light or medium-sized paper, 
only one color box is necessary; but, with a hard-sized sheet, it 
is sometimes necessary to run two color boxes, in order that the 
second box may cover up the light spots from the first color box, 
and thus give a uniform shade. The degree of penetration of 
the color solution increases with the temperature of the solution 
and the heat of the calender stack; hence, in order to obtain 
uniform results, these two factors must be kept constant. A well- 
formed sheet will also dye more evenly than a wild sheet, because 
calender coloring accentuates any irregularities in the paper itself. 
Where trouble is experienced because of streaking on the 
calenders, the addition of a small amount of soap in the dyestuff 
solution will usually eliminate this difficult^^ 

117. Combination Method. — A combination method, wherebj- 
the coloring is done partly in the beater and partly on the 
calender, is often used. The relative proportion of the two 
methods thus employed depends upon the cost and the results 
desired. The principal use of calender coloring is on different 
grades of box boards and container boards, and a great variety of 
economical shades may be produced on this type of stock. 


Through this method of coloring, different shades on opposite sides 
of the paper or board can be produced by having the water boxes on 
opposite sides of the calender stack j&lled with different dyestuff 
solutions. Just sufficient solution is taken up by the sheet to 
give it a good finish on the calender stack. Sometimes steam 
is used in hollow calender rolls. 

118. Tub Coloring. — Tub coloring is used to a very limited 
extent. In this process, the paper, in a semi-dry condition, is 
passed through a tub, situated approximately half way or two- 
thirds of the way to the dry end of the machine; and after passing 
through this bath, and then through squeeze rolls, it is dried. 
There are no distinct advantages to this type of coloring; it is 
used only in special cases, where a slight saving in cost over 
beater coloring can be made, and when greater penetration can 
be obtained at the same time than by calender coloring. 

119. Oatmeal Papers. — Oatmeal papers are used practically 
exclusively for wall papers, and the oatmeal effect may be 
obtained by washing a suspension of wood flour over the surface 
of the sheet on the wire. In a majority of cases, the paper itself 
is highly colored, while the wood flour is in its natural state of 
color. In some cases, however, the body of the paper is white, 
while the wood flour is colored in various hues. In some isolated 
cases, ordinary groundwood is used in place of the flour, but this 
has never proved satisfactor}-, on account of being too coarse. 
Dyestuffs used for this purpose should have the properties of 
being fairly fast to light, and of resistance to the alkali that is in 
the paste used for hanging these papers; and must have the 
property of not bleeding, in order to prevent the wood flour from 
absorbing the dyestuff in the paper. On account of the require- 
ments just mentioned, direct dyestuffs are generally used for 
this type of work; but, by careful attention to their method of 
application, certain acid and basic colors are used very efficiently. 
Another method is to mix the stock in separate chests and bring 
them together in a specially prepared head box on the machine. 

120. Mottled or Granite Papers. — Granite or mottled papers 
are made by adding a small percentage of highly colored fibers 
to the furnish. The amount of these colored fibers ranges from 
^% to 3%, depending on the intensity of the granite effect 
desired. The colored fibers are usually made bj- dyeing either 
rag or unbleached sulphite with direct colors. The colored 


fibers are prepared by coloring a beater of stock, in the regular 
manner, with direct colors, adding 40 to 50 pounds of salt per 
1000 pounds of stock, heating to 140°F., cooling to below 100°F., 
adding a small amount of size and alum, and then subsequently 
running the stock into laps on a wet machine. During this last 
procedure, any color that is only mechanically fixed to the fiber 
will be washed out; hence, the pulp in the laps will not bleed 
when it is mixed with the white or natural stock, in the production 
of the granite papers. 

Very good effects in granite papers are obtained by adding to 
the white stock two or three different shades of pulp that have 
been colored in this manner. Where the granite fibers are black 
in color, black stockings are often used. Varied effects can also 
be obtained by using wool, jute or various long grass fibers in 
place of rag or unbleached sulphite. 

121. Blotting Papers. — The type of color used for blotting 
papers depends upon the grade or furnish of the paper. In the 
better grades of blotting paper, manufactured from a large 
percentage of rag stock and sometimes containing a small amount 
of soda pulp or unbleached sulphite, direct dyestuffs should be 
used exclusivel}'. In the verj^ cheap grades of blotting paper 
containing unbleached sulphite, soda, and ground wood, basic 
colors are as suitable as direct dyestuffs. 

Direct dyestuffs can be more efficiently dj-ed on the fiber by 
the addition of 30 to 50 pounds of salt per 1000 pounds of stock, 
and raising the temperature to 140°F. The addition of a 
minimum of 10 pounds of soda ash tends to brighten the shade 
of the direct dyestuffs, and it has no injurious effect on the paper. 
The objection to the use of soda ash mentioned previously does 
not apply here, as the paper is not sized. In order more firmly 
to fix the dyestuff on the fiber, it is the practice of some mills to 
add a small amount of alum to the beater; but this practice 
should be discouraged for two reasons: First, any quantity of 
alum over | % to 1 % has the property of destroying the blotting 
qualities of the paper; second, as stated in Art. 13, alum deadens 
the shade of direct dj^estuffs, and, in the presence of the heat 
of the dryers, it often tends to vary the shade sufficiently to make 
uniform results difficult to obtain. On the cheaper grades of 
blotting paper containing groundwood, the addition of a small 
quantity of alum aids materially in the retention and uniformity. 
Because of the fact that they have no direct affinity for any fibers 


and require a mordant, acid colors should never be used for this 
type of work. 

122. Duplex Papers. — ^Duplex papers can be made at the 
calenders of a Fourdrinier machine by coloring one side of the 
calender. In the case of two-ply or multiple-ply sheets made on a 
cjdinder machine, either the top or bottom liner or both can be 
colored. Duplex sheets can also be made on a Fourdrinier or 
Harper machine by having a vat and C3dinder mold attached to 
the paper machine, and having the paper from this cylinder mold 
carried bj^ a felt, so as to meet the paper from the machine wire 
just after passing through the couch rolls, where the two papers 
are pressed together into the duplex sheet, as described more 
fully in Section 1, Vol. V. 

123. Spray Dyeing. — Spray dj^eing is a relatively new process ; 
and it is only within the last few years, that it has developed to 
considerable commercial importance. Its advantage lies in the 
fact that very beautifully colored papers can be produced at a 
low cost, with a minimum consumption of dyestuff. 

Spray dyeing may be divided into two types: In the first type, 
a dyestuff solution is sprayed onto the sheet of paper bj^ means 
of a spray nozzle, using air under high pressure to force the 
color solution through fine orifices; and so arranged that it will 
strike the paper either before or after passing over the first 
suction box, depending on the effect desired. In the second type, 
the d3^estuff is spattered on the sheet from rotating brushes, 
which travel through the dye bath and then against a baffle 
plate, which draws back the hairs of the brushes; and when they 
pass the baffle and return to their original position, the color is 
thrown on the sheet. Direct dyestuffs are more suitable for 
this work. 

124. Cloudy Effects. — There are numerous methods for 
obtaining cloudy effects, either by washing undyed pulp onto a 
colored stock as it passes over the machine wire or by coloring 
the pulp and washing it onto a white sheet; in either case, direct 
dyestuffs should be used. Where the stock used is either 
unbleached wood pulp or groundwood, basic dyestuffs may be 
employed for coloring the body of the sheet. 

125. Crepe Tissues. — Crepe tissues are colored by the dipping 
process, which is the same, in many respects, as tub coloring. 
This coloring is done at the same time as the creping of the paper. 


The machine required consists of two steel rolls, the bottom one 
of which is covered with a closely woven woolen cloth or with 
rubber, while a doctor blade crepes the paper as it is removed 
from the upper steel roll, after the paper has passed between the 
two rolls. The lower roll is always in contact with the dyestuff 
solution, which is maintained at a constant level in the color box, 
in which this lower roll revolves. Acid colors are most suitable 
by far for this type of work, because of their even dyeing quahties; 
though for very heavy shades, where brightness is more essential 
than even dyeing qualities, basic colors are used. Direct dyestuffs 
are employed for this type of work only in rare cases, where 
certain fastness properties must be maintained. 

One essential in the coloring of crepe tissues is to maintain a 
constant temperature of the dj^estuff solution, in order to obtain 
a uniform depth of shade. In some cases, a small amount of 
casein is added to the dyestulT solution, as it causes the paper to 
adhere more securely to the upper steel roll, and gives a better 
creping effect. 

126. Parchment Papers. — In the manufacture of parch- 
mentized paper, the dyed paper is passed through a bath of 
strong sulphuric acid. Only dyestuffs that will not be affected 
by sulphuric acid can be used for this type of work. The tests 
referred to in Art. 63, will indicate the action of each dj^estuff 
against acids, alkahs, etc., and should be applied when making 
a selection of dyestuffs for this work. The most secure method 
is to submit each individual problem of this type of work to the 
laboratories of the dyestuff manufacturer. 

127. Vulcanized Papers. — In the manufacture of vulcanized 
papers, the dyestuff used must not be affected by the zinc 
chloride-hydrochloric acid solution employed in vulcanizing. 
Certain direct dyestuffs are suitable for this work; but, as men- 
tioned in Art. 126, the safest way is to submit each individual 
problem to the laboratories of the dyestuff manufacturer. 



(1) (a) Name the principal groups of coloring matters. (6) 
Which group is the most important, and why? 

(2) What are the distinguishing characteristics of acid, basic, 
and direct dyestuffs? 

(3) What particular values are possessed by pigments for 
coloring paper, considered from the standpoint of (o) cost? 
(6) permanence? (c) tinctorial power? 

(4) How is Prussian blue formed? Would it be advisable to 
use it for coloring soap wrappers? 

(5) Mention the principal steps in producing a dyestuff 
from coal. 

(6) (a) What is meant by standardizing the strength of a 
dyestuff? (b) How is this necessary operation sometimes abused? 

(7) Explain in detail how to determine whether a particular 
color is a single dyestuff or a mixture. 

(8) Describe a method for estimating the coloring power of 
a dyestuff. 

(9) What standard solutions should be kept in the color 
testing laboratory, and why are they needed? 

(10) (a) What classes of paper should be fast to light? (6) 
Is change of color always due to the dyestuff? 

(11) After making laboratory test and calculation, what pre- 
caution is necessary when coloring a beaterfull of half-stuff? 

(12) Mention the principal parts of an equipment for a color 
room in a paper mill. 

(13) Explain the dissolving of a dyestuff. 

(14) What factors affect the shade of a paper. 

(15) Explain the action of size and alum when coloring paper. 

(16) (a) Explain what you understand by mordanting; (6) 
why is the use of tannic acid for this purpose objectionable? 

(17) When the water is hard, what precaution should be 
taken if a basic dye be used? 

§5 53 


(18) How does the density of the stuff in the beater affect 
the coloring? 

(19) (a) what is two sidedness, and how is it caused? (6) how 
can it be minimized? 

(20) Describe the process (a) of calender coloring; (6) of 
making mottled papers. 



(PART 1) 

By J. W. Brassington 



1. Introductory. — The object of this Section is to explain, in so 
far as is possible, the best methods of handling a paper machine 
in order to obtain the best results, both as regards the quantity 
and the quality of the paper produced. It is not the aim to 
train paper-machine designers, but to impart to paper makers 
the essential knowledge regarding the construction and operation 
of paper machines and the auxiliary apparatus. If the paper 
maker finds herein real information as to causes of trouble in 
paper-machine operation and their remedy, and hints of how to 
improve working conditions, and of how to avoid trouble, the 
purpose of this Section will be fulfilled. The information here 
given has been selected from the advice imparted by, and the 
opinions of, practical paper makers throughout the world. It 
is not possible to record here all the information thus collected; 
hence, only the most important facts are given. The student 
should keep his own notebook, and should enter in it all interest- 
ing facts that come up in the course of his experience, particu- 
larly those relating to any troubles that arise, their cause, and 
their remedy. The mill is the student's laboratory, and his 
daily work a series of demonstrations and experiments. They 
should be recorded. Such a notebook, if carefully kept and 
indexed, will be of great value and assistance in his future work. 
§6 1 



Before explaining in detail the various machines and appli- 
ances, it is advisable to trace the course of the paper through the 
machine; in this way, a knowledge of some of the most important 
features concerning the manufacture of paper will be impressed 
on the mind, and the relationship of the various parts to one 
another will be made clear. It will be of advantage to the 
student to give careful attention to the following article. 

2. Course of Paper through Machine. — The principal parts 
of the modern paper machine, and the course of the paper through 
it, are shown diagrammatically in Fig. 1. On account of its 
length, the drawing has been cut in two in the middle, the right- 
hand part being placed below the left-hand part. Here a and b 
indicate the same point when the two parts are united. 

P D „ 

Fig. 1. 

The first section (the upper, or left-hand, part) is called the 
Fourdrinier part, or wet end; this will be described first. The 
stock is conducted from the flow box X over an oilcloth or 
rubber apron to the wire screen A, which is driven by the couch 
roll Bi, and is supported by the breast roll C, table rolls D, and 
wire rolls E. The deckle straps F keep the stock from running 
off the edges of the wire. Much water drains through the wire 
at the table rolls, more water is taken out by the suction boxes 
G, and the fibers are laid down by the dandy roll H (sometimes 
omitted) and the couch roll B^. If a suction couch roll be used, 
air pressure is substituted for the weight of the upper roll jBo. 

The second section (which follows the wet-end part) is called 
the press part. Here the sheet is carried by the felts J\ and Ji, 
and passes between the press rolls Ki, K^ and Kz, Ki (some 
machines have three or four such presses), where more water is 
squeezed out, the sheet is further pressed and is prepared for a 


smoother finish. The felts are carried on rolls L, sometimes 
over a felt suction box M. The direction of rotation of the last 
press is usually reversed, so as to give the paper approximately 
the same surface on both sides ; and where the course of the paper 
is thus changed, the sheet is supported by paper-carrying rolls A^. 

From the presses, the paper (now containing about 60% to 
70% of water), passes to the dryers P, shown in the lower part of 
the illustration. These latter are steam-heated cylinders; the 
paper is kept in contact with their hot surfaces by cotton (or 
canvas) felts, and most of the water left after pressing is here 
evaporated. The number and the size of the dryers varies in 
accordance with the weight and the grade of the paper, and with 
the speed of the machine. The opposite side of the sheet is 
next to the iron on successive dryers, thus drying the paper more 
evenly and giving a more uniform finish. The finished sheet 
contains from 7% to 10% of moisture. 

Most papers are finished on the machine by passing through 
the calenders R {calender stack). These constitute a set of very 
smooth iron rolls, which press heavily on the paper. By reason 
of their weight and the friction generated when the paper passes 
through them, the paper is "ironed out," as it were. This 
operation is called calendering. The web is then wound on the 
reels T, of which there are several types. When a reel is full, 
the paper is transferred to an empty one, and the full reel is 
thrown out of gear. The paper from the full reel is slit into 
strips by revolving slitters and wound in rolls of the width and 
diameter desired. The slitter is shown at S and the re-wound 
roll at W. 

The several sections of the machine must be capable of adjust- 
ment to slight variations in speed in relation of one to another, 
and provision is also made for varying all sections in unison. 
There are several methods of driving the paper machine, and 
these will be described after the several sections just mentioned 
have been explained in detail. 


3. Circulation of Stock. — Fig. 2 shows a paper-machine wet-end 
in plan and elevation. The vertical stuff chest C receives the 
stock, which is continually agitated in it; and which either flows 
into it or is pumped into it from the beater, mixer, or beater 



chest, usually passing through the Jordan engine. The stuff 
pump A delivers the stuff from the stuff chest C to the regulating 
box B, and it flows from the latter over the riffler or sand trap 
D to the screens F and F. In the case of stock for fine rag papers, 
it also passes over a magnet E before reaching the screens F. 
The screened stock passes through pipe G into the flow box H, 

X V 






W ^M^ll A 





Fig. 2. 

from whence it flows upon the wire. The overflow from flow 
box H goes to the white-water box W. The centrifugal pump 
M sucks what water is needed to dilute the stock from the 
white-water box, and discharges it through pipe N into the 
regulating box B. The overflow from the regulating box goes 
back to the stuff chest. The remainder of the white water is 
generally treated, in a manner to be described later, for the 
recovery of fiber, etc. Attention is called to the pump S, which 
is here shown in dotted lines because it is under the machine- 


room floor and in the basement; this is the pump that main- 
tains a vacuum on the suction boxes. The vacuum system 
is provided with a separator, for removing air from the water 
that is drawn from the paper. 

It is important that the student famiharize himself with the 
circulation of the stock and water, using Fig. 2 and the diagram 
in Art. 21 as guides, and that he keep the main principles of this 
circulation clear in his mind. 

4. Paper-Machine Room Details. — Stuff chests may be 
horizontal or vertical, and there maj^ be one or two to a machine. 
Both stuff chests and stuff pumps are described in Section 3, 
Beating and Refining. Plunger stuff pumps may be single, 
double, or triple. They are always single acting. In some 
mills, centrifugal pumps are used. Pumps with 1, 2, or 3 plungers 
are called simplex, duplex and triplex respectively. The regulat- 
ing box, of which there are several patented tj^pes on the market, 
may have two, three, or four compartments. The rifflers may 
be simply wooden boxes (troughs) with suitable baffles to prevent 
the passage of heavy particles. The screens may be flat or of the 
rotary type. The flow box may have two, three, or four com- 
partments; and the overflow from the flow box may go to the 
beater chest instead of to the white-water box. The discharge 
of white water from the centrifugal pump may go to the regulat- 
ing box, to the beaters, or to save-alls. Every mill presents 
slight differences in details from every other mill, in accordance 
with the ideas of the man in charge. The student, therefore, 
should grasp the general ideas of paper making; after which, he 
can design his own rifflers, regulating boxes, etc., and he can 
choose what circulating methods he prefers. 



5. Description of Stuff Chests. — The stufiE chest is a large 
cylindrical-shaped tank, usually vertical. It may be made of 
iron, wood, or concrete, care being taken that the interior is 
smooth and that there are no corners or angles for the stuff to 
lodge in. Fig. 3 shows a vertical stuff chest, and Fig. 4 shows a 
horizontal stuff chest. The central shaft revolves at a moderate 


speed, so as to keep the pulp thoroughly mixed. The paddles 
make from 15 to 20 r.p.m. when making rag papers. If the 
agitator paddles turn too rapidly, they tend to churn light 

Fig. 3. 

fibers into soft knots; if they turn too slowly, they cause variation 
in weight by allowing the heavier stock to settle. More detailed 
descriptions of Figs. 3, 4, 5 and 6 will be found in Section 3. 


With vertical chests, the gearing may be so located underneath 
them that dirt and grease cannot drop into them . When the gear is 
placed below the chest, a stuffing box and gland are used to prevent 
leakage. This type of stuffing box is used also on the end of the 
shaft that extends through the sides of horizontal stuff chests to 
the driving mechanism. A good design of stuff chest will permit 
thorough washing and complete emptying, so as not to waste 


Fig. 4. 

6. Capacity and Size of Stuff Chests. — Vertical stuff chests are 
generally about 12 feet in diameter and from 6 to 14 feet deep, 
according to the size of the machine. A stuff chest should hold 
enough (two beatersful, at least, especially of colored stock) to 
supply the paper machine for an hour or more, and to give plenty 
of time for the beaters to replace their contents. If the stuff in 
the chest is allowed to run low between charges from beaters or 
mixers, there is likely to be variation in the weight of the paper, 
due to pulsations in the chest. The consistency of the stuff in 
the chest is from 2\% to 3%. The stuff in the beater is diluted 
by the water required to wash it down to the beater or Jordan 
chest — which is necessary when a Jordan is used and where 
colored papers are made. 

The size of a stuff chest is readily calculated. For example, 

suppose a machine to make 12 tons of paper per day of 24 hours, 

and it is desired to find the size of a vertical stuff chest for this 

machine. The calculation would proceed as follows: 

. . , , , 12 X 2000 
Average amount of paper made per hour = ^^ 

= 1000 lb. The beatershold,say 12001b. of paper pulp; and since 
the capacity of the stuff chest must be at least 2 beatersful, it 
must hold 1200 X 2 = 2400 lb. of paper. Assuming that the 


consistency of the stuff is 2.4%, the weight of the stuff in the 
chest is 2400 -^ 0.024 = 100,000 lb., a cubic foot of which weighs 

from 62.5 to 63.0 lb. Assuming that it weighs 62.5= ~v^~ lb., 

the volume of the chest is 100,000 4- -y^ = 100,000 X -rnna 

16 1000 

= 1600 cu. ft. If the inside diameter of the chest be taken as 12 ft., 
the area is 12' X 0.7854 = 113.1— sq. ft.; consequently, the 
depth of the chest is 1600 ^ 113.1 = 14.15 ft., say Uh ft. 

7. Care of Stuff Chests. — The stuff chests should be well 
cleaned whenever there is an opportunity during periods that the 
mill is shut down ; and, particularly, this must alwa3^s be done when 
the kind of paper being made is changed. Wooden stuff chests 
that are not in use should be kept full of water, being freshly 
filled at intervals of, sa}', three or four weeks; this keeps the 
wooden staves water soaked, and it prevents leaks and deforma- 
tion. The iron straps should be painted periodically, to keep 
them from rusting. Agitation of the contents of a stuff chest is 
very important; it can be assisted by allowing the centrifugal 
pump that takes from the Jordan chest to discharge tangentially 
into the stuff chest, thus causing the stock to tend to flow along the 
outer wall of the chest. This method is only applicable to very 
light papers, such as newsprint or cheap magazine papers. A 
special mixing chest for newsprint paper is described in the 
Section on Beating and Refining. 

8. Horizontal Stuff Chests. — As previously stated, stuff chests 
may be horizontal as well as vertical. Some paper makers prefer 
a horizontal chest having a series of vertically acting paddles, 
which are so made that the stuff is forced one way along the 
center of the chest, and is then returned the other way, on the 
outside, near the shell. This result is obtained by reversing 
the inclination of the paddles on the revolving arms. 

In mills where colored papers are made, horizontal stuff chests 
are not considered to be a good installation. When a color is 
poor, and the strength or brightness of the color is to be "brought 
up" or intensified by adding more color in the beaters, horizontal 
stuff chests do not produce results on the machine as quickly as 
vertical stuff chests; the contents of a beater do not "mix in" as 
quickly, when they are dumped into a horizontal stuff chest. 
Furthermore, the horizontal chest has the disadvantage of 


spattering, when it is partly full, and of requiring stuffing boxes 
for the agitator draft. 


9. Description of Plunger Pump. — The contents of the machine 
stuff chest are pumped to the regulating box by the stuff pump, 
which has its suction pipe connected to the bottom of the stuff 
chest. Fig. 5 shows a simple stuff pump of the usual design; a 
more extended description 
of it is given in Section 3, 
Beating and Refining. 

Fig. 5 illustrates a single- 
acting, single-cylinder, 
plunger pump . The plunger 
A is moved up and down 
by the revolutions of an 
eccentric. As the plunger 
goes up, the ball valve F is 
lifted, and the stuff from the 
stuff chest is sucked into the 
space D and into the pump 
cyhnder. When the plunger 
reverses its movement and 
goes down, the ball F drops 
to its seat, closing the open- 
ing, and the ball valve E is, 
in its turn, forced off its 
seat. Liquid equal in vol- 
ume to the volume displaced 
by the plunger during its 
downward movement can- 
not now find room in space 
D, and it is therefore forced 
to flow through the opening 
left by ball E into the dis- 
charge pipe C, which delivers it to the regulating box. The 
pressure forcing the liquid through the discharge pipe is that 
exerted by the driving eccentric on the plunger. When the 
plunger again reverses, beginning its upward stroke, the pressure of 
the water in the discharge pipe (the back pressure) forces ball E 
to its seat, and thus keeps the liquid from flowing back into the 

Fig. 5. 


cylinder. This type of plunger pump is largely used on machines 
of small size; the eccentric is keyed to a revolving shaft, which is 
driven by pulley and belt. Hand holes, covered by plates H, 
scn-e for replacing balls, cleaning, etc. 

Double and triple plunger pumps, of the same valve and 
cj'Under design, are used for larger machines that call for a greater 
stuff-pump dehvery per minute. These pumps give more 
impulses per minute, and there is a more regular flow of liquid and 
less shock. Except that they are gear driven instead of eccentric 
driven, the general design is the same as in the pump just 
described. The advantage of using gears is that the belt pulley 
can turn faster and the belt used may be smaller, for the same 
power, the gears reducing the speed of the plunger to that 

10. Size of Pump. — It was previously stated (Art. 6) that the 
average consistenc}^ of the stuff in the chest, and which is to be 
pumped, is about 2.5^; that is, for any given volume of stuff, 
approximately 2.-5 parts are pulp and 97.5 parts are water, which 
is a ratio of 97.5 : 2.5 = 39 : 1. In other words, there are about 
40 lb. of water to 1 lb. of pulp. In some cases, this ratio 
may be as high as 50 : 1, and since it is always necessary to pro- 
vide for extreme cases, this last ratio will be taken in calculating 
the size of the pump to be used. Suppose, as in Art. 6, that the 
machine is to make 12 tons of paper per day of 24 hours, or 1000 
lb. per hour; this is equivalent to 1000 -^- 60 = 16| lb. per min. 
The plunger of the stuff pump must therefore displace approx- 
imately 16| X 50 = 833^ lb. of stuff per min. Taking the weight 
of a cubic foot of the stuff as 62.5 lb. = ^^^ lb., the volume of the 
stuff delivered by the pump is 833| -^ i?f^ = 833^ X 0.016 = 13^ 
cu. ft. per min. = 13^ X 1728 = 23,040 cu. in. per min. It is not 
good practice to run a stuff pump over 30 r.p.m., which, for the 
single-acting, simple pump just described, gives 30 working 
strokes per minute. Consequentl}', the displacement of the 
plunger per stroke (revolution, in this case) must be, at the very 
least, 23,OiO -^ 30 = 768 cu. in., under the conditions assumed. 
Since in 1 U. S. gal. there are 231 cu. in., the plunger must displace 
768 -4- 231 = 3.32 gal. per stroke. It is good practice to use 
large pumps, since they can be run more slowly and will last 
longer without repairs; hence, it would be advisable to make the 
displacement of this pump about 4 gal. per stroke. A cjdinder 
9 in. in diameter and 15 in. long holds 4.13 gal.; therefore, the 


diameter of the plunger might be made 9 in. and the stroke might 
be made 15 in.; that is, the pump would be 9 in. X 15 in. It would 
not be advisable to use a smaller cylinder, because no allowance 
has been made for "slip." In any case, a pump must have 
excess capacity, in order that a constant head be maintained on 
the discharge orifice of the regulating box, the overflow from the 
regulating box returning to the stuff chest. 

11. Horsepower of Pumps. — When calculating the horsepower 
required to pump stuff, it is important to remember that the 
pressure required to pump stuff is often 2| times as great as that 
required to pump water against the same lift, because of the 
greater friction in the pipes. 

Assuming, as in the last article, that the pump is to deliver 833^ 

lb. of stulT per min., and also assuming that the total lift is 40 

833- X 40 
ft., the theoretical horsepower is qq nnn — — 1-01 h.p. This 

result assumes an efficiency of 100%; but the actual efficiency of 
such a pump will not exceed about 50%, and the actual horsepower 
when water is pumped will be 1.01 -r- 0.50 = 2.02 h.p. When 
pumping stuff, however, the resistances may be 2.5 times the 
resistances when pumping water, as stated in the last paragraph; 
consequently, the actual horsepower is 2.02 X 2.5 = 5.05 h.p., 
or, say 5 h.p. 

12. The Work of the Stuff Pump. — The work required of a 
stuff pump in a paper mill is very severe, and is continuous. The 
paper maker demands a reliable pump, — one that will always do 
its work faithfull}^ under exceptionally trying conditions, — and 
he rightfully claims that the commercial efficiency of a fool-proof, 
reliable stuff pump is a vital essential part of his paper-making 
equipment. The stuff pump may be considered the heart of the 
paper machine, and the suction pump may be called the lungs; 
so long as both are always working properly, the paper maker 
does not grudge them a comparatively large input of power. 

In order to reduce the work done by a stuff pump for any given 
or required delivery, — thus not only reducing the power neces- 
sary to drive it but also increasing the life of the pump, by reliev- 
ing it of unnecessary wear and tear, — it is always advisable to 
make the suction pipe of ample area and as short and direct as is 
possible; it should be connected to the bottom of the stuff chest, 
and the stuff should feed into the pump by gravity whenever 


practicable. The delivery pipe should be at least as large in 
diameter as the discharge outlet of the pump, and as much larger 
as is convenient. In some mills, copper or brass pipe is used for 
conveying the stuff so as to minimize contamination by iron. 

A more complete treatment of the subject of pumps will be 
found in the Section on General Mill Equipment, Vol. V. 


13. Functions of the Regulating Box. — Two important func- 
tions of the regulating box are: first, it regulates the amount 
of stock going to the paper machine; second, it regulates the 
consistency of the stock going to the paper machine. The amount 
of stock is regulated by so operating a gate or valve that just the 
right amount of the stock which is pumped from the machine 
stuff chest by the stuff pump, is delivered to the mixing compart- 
ment or mixing box. The consistency of the stock is regulated 
by controlling the amount of M^ater (usually white water collected 
under the wire) with which the stock is diluted. The amount of 
actual fiber delivered by the stuff pump varies with the consist- 
ency in the chest; and the extent of the dilution must be changed 
in accordance with the freeness of the stock and the speed of the 
machine. A slow stock requires less dilution, because the water 
then stays longer with the fibers. 

14. Uniformity of Weight of Paper. — In the earlier types of 
regulating box, the machine tender changes the amount of 
stock going to the machine when he wishes to change the weight 
of the paper, or when he finds that the weight has accidentally 
changed, due to the stock in the chest becoming thicker or 
thinner. Likewise, he changes the amount of water added to the 
stock in accordance with his observation of its behavior on the 
wire, especially during the formation or interweaving of the 
fibers. This, however, is only one of several adjustments he may 
have to make. In order to relieve the machine tender of some 
of this responsibility, and to get more dependable uniformity, 
several automatic regulating boxes have been devised. 

The principal factor in securing uniformity of weight is uni- 
formity of the consistency. As pointed out in the Section on 
Beating and Refining, the logical place to control the consistency 
is when the stuff passes the Jordan on its way to the machine 


S w 




chest. By keeping the consistency uniform, regulation at the 
machine is greatly simplified. 

15. A Simple Regulating Box. — A very simple regulating box 
is shown in Fig. 6. The stuff pump discharges through pipe E 
into compartment K. An adjustable gate G admits the required 
amount of stock to the mixing compartment or box M, in which 
it is diluted and mixed with white _ 

water. The amount of the white 
Vt^ater admitted is controlled by a 
valve on pipe W , set by the machine 
tender in accordance with the con- 
dition of the stock. The excess stuff 
flows over partition B into compart- 
ment F, and goes back to the stuff' 
chest through pipe i7, There is 
usually a gate on the discharge L to 
the sand trap, screens, and machine. 
If the consistency of the stuff is uni- 
form, this gate can be made to control 
the amount of stock furnished the 
machine; since with a constant head, 
the volume delivered depends only on 
the size of the outlet. It may here 
be mentioned that stock is stuff that 
has been diluted. The mixing of stuff 
and white water may take place in a 
separate stock box. 

16. Conditions Governing Automatic Regulation. — Automatic 
regulation involves mechanical regulation at one or more of four 
points: (1) admission of white water at intake of stuff pump; (2) 
operation of gate G, Fig. 6; (3) control of valve admitting white 
water to mixing box; (4) operation of gate L. The principles 
generally involved are: the resistance to immersion of a float, 
which varies with changes in the consistency of the stock; the 
friction of the stock as it passes through a pipe, which varies 
with the consistency of the stock; the slight change in weight of a 
unit of volume of stock, which results from changes in consistency. 

The advantage of a mechanical automatic regulator is that 
variations in consistency are detected in the stock before it 
becomes paper; the machine tender would not be aware of these 


Fig. 6. 


variations until he had weighed a sample of the finished paper. 
However, the use of a mechanical automatic regulator does not 
relieve the machine tender of the necessity of making proper 
adjustments when changing the weight, width, or speed of the 
paper, or in preserving the general character of the stock. The 
behavior of the stock on the wire may require furthur adjust- 
ment of consistency. 

17. Regulating the Consistency. — It is unnecessary to repeat 
here the description of the consistency^ regulator, which was 
illustrated and explained in the Sections on Treatment of Pulp, 
Vol. Ill, and in Beating and Refining. The regulator there 
described will control the consistency of the stuff going to the 
machine chest to within 5% of the consistency desired. This is 
accomplished by keeping the stuff a little too thick in the beater 
or pulp chest, and bj^ controlling the amount of white water or 
fresh water admitted to the suction side of the stuff pump. 
With stuff of accurately controlled consistency, it is only neces- 
sary for the machine tender to set his valves and gates for the 
amount of stock and diluting water that accords with the speed 
of the machine and the character of the stock. Variation in weight 
can then occur only because of mechanical trouble with the drive. 

18. Automatic Regulator. — In Fig, 7, a regulator is shown 
which has been designed to regulate the volume of stuff furnished 
the machine as the consistency varies, in order that the weight of 
fiber supplied to the machine may be constant. Delivery from 
the stuff chest is through the pipe A to box B, any excess flows 
over the dam C, and is pumped or flows by gravity back to the 
machine chest through pipe D. The stuff for the machine passes 
the adjustable gate E, which is moved by pin F and levers G and 
H, the latter being actuated by the float K. The stuff passes 
down the spout L, works up around the float K, and into the 
annular ring M, from which it flows to the machine. The float 
may be weighted according to the usual consistency of the stuff; 
it sinks in thin stuff, and it is raised by the friction and greater 
density of thick stuff, thus opening or closing the gate E accord- 
ingly. No outside power is required to operate this mechanism, 
which is very simple. The amount of white water or fresh water 
used to dilute the stock must be regulated by other means. 

19. Automatic Stuff Box. — The regulator shown in Fig. 8 is 
called an automatic stuff box. Stuff from the chest enters 


compartment A and leaves it through outlet F, which is so 
divided by the bottom of spout H that a part or all of the stuff 

Fig. 7. 

may go either to the overflow or back to the chest through B, 
or it may go to the machine through C. A clean-out gate is 
shown at G; it is operated by handle T. 

Fig. 8. 

The relative proportions of the stuff going through B and C 
are controUed by the dividing gate K, which lets more stuff into 
B or C, according as this gate is raised or lowered. The move- 


ment of gate K is caused by the float M, which is suspended from 
the levers L. When the stuff is coming through, the gate D is so 
adjusted by means of the hand wheel E that the required amount 
goes to the machine and the remainder goes back to the chest. 
The float is counterpoised by the weight W, which is adjusted to 
balance the float in stock of the proper consistency. If the stock 
becomes thicker, less fluid, its buoyant action is increased, the 
float rises, and the gate K, which is attached to it, also rises; 
the changed opening thus obtained admits less stuff to the 
machine and more to the chest. If the stuff becomes thinner, 
more fluid, more of it will then be required on the machine; its 
buoyant action then decreases, and the float M falls. This 
causes the gate K to move downward, partially closing the open- 
ing to the chest, which sends less stock to the chest and more to 
the machine. The stuff may be thinned to the proper state of 
dilution for machine operation by adding water at any conveni- 
ent point after the stuff leaves the stuff box. The regulation of 
this water is not provided for in this apparatus, since the slight 
change in the flow of stuff required to maintain uniform weight 
of paper would make only an almost imperceptible change in 
the density of the stock on the wire. 


20. White Water. — White water is the term used to designate 
the water that flows through the wire of the paper machine and 
into the save-all boxes under the wire; it is the water that is 
removed by the table rolls as the paper forms, and by the suction 
boxes. Naturally, this water contains considerable fiber and 
filler, and it should not be wasted. 

As the white water collects in the save-all boxes, it flows, b}^ 
means of wooden troughs, to the back, or driving side, of the 
Fourdrinier and into a box that is piped to the suction intake of a 
centrifugal pump. This pump discharges as much white water 
into the regulating box as is required to dilute the stuff in com- 
partment M, Fig. C. This constant circulation is also main- 
tained in the case of a cylinder or board machine. There is, 
however, a comparatively large proportion of the white water 
that escapes the save-all boxes; this settles in a pit under the 
wet end of the machine, or it flows over the dams of a cylinder 
machine. It is often necessar}^ to permit quite a large quantity 


of stuff to flow to the pit; and if there is no means of recovering 
this waste, it ultimately finds its way to the sewer. 

21. Paper -Mill White Water Flow Diagram.— A typical paper 
mill system is drawn for machines having trays and is shown with 

Shfffrom Chefif 

906 6. 

Regulating Box 

Excess SucVion 

9316. 0.1111% &2ST 



F.w.sooe. ■ 


Mixing Box 

4793 6. 




181 T 

Head Box 





181 T 


1231 G 

130 T. 


To While Wafer Sysiem 

130 T. 



3775 6. 




tray and suction water supplied to a mixing box having baffles so 
arranged that all the tray water is used before any of the suction 
water. The supply to the machine includes groundwood and 
sulphite pulp, the worked-up "broke" and the recovered stock 




from the excess white water. The stock is shown as "air-dry" 
consistencies up to the dryers, purposely to bring out the "book 
figure" shrinkage between the "air-dry" pulp and the finished 
paper. This diagram shows where and how much fresh water 
is added, how much white water is removed, how much fiber 
is contained in it, and where it re-enters the system or is dis- 
charged. The width of the stream is proportional to the volume. 
Of course, if consistency figures vary from those given — and 
they usually will, the volume of water flow must be changed in 

In this diagram, which is drawn for a 120-ton newsprint unit, 
the following abbreviations are used: 

F. W. = fresh water 

G = gallons per minute 

% = consistency, air dry. 

T = tons per 24 hours, including "broke." 

A sulphite-mill system serves as a good outlet for excess paper 
mill white water. For a 25-ton pulp mill, 500 to 600 gallons 
per minute of the paper-mill water carrying, say, 3 tons of stock, 
could be used to advantage. Under this condition the loss from 

the sulphite mill will be 
js\M greater ; but still about 80 % 

of the stock in the paper- 
mill water will be retained 
with the sulphite stock. 
The use of this paper-mill 
water also may necessitate 
added deckering or press- 
ing equipment for the 
sulphite, mainly due to 
slowing up the stock. 

22. Cylinder Type of 
Save -All. — Several types 
of save -alls are fully de- 
scribed in the Section on Treatment of Pulp, Vol. Ill, one of 
these being shown in Fig. 9. Here, a cylinder 4, covered with 
fine wire, is revolved in a vat 8, into which the white water 
flows, generally by gravity, through inlet 7. The white water 
flows through the fine wire covering of the cylinder mold, leaving 
the suspended fibers clinging to the outside surface. As the 

Fig. 9. 


surface of the revolving cylinder emerges out of the water, it 
passes under a soft couch roll 2, which picks off the adhering 

fibers from the wire. The couch roll is, in turn, scraped by a 
wooden doctor 1, which is so inclined that the pulp fibers are 


taken off the couch roll and guided by a board 3 into a passage 10. 
From this passage, pulp fibers thus scraped off are conducted 
to a convenient receptacle, as a truck, from which the pulp is 
shoveled into the beaters, or conducted in suspension to the white- 
water or stock sj^stem. 

]\Ian3^ developments of this type of save-all are in use. Fig. 
10 shows a polygonal drum 7, wound wdth brass wire, which is 
covered for five-sixths of its perimeter by a part of the endless 
felt 8, in order to save a larger proportion of the finer fibers. 
This felt is of considerable length; it is carried out of the top of 
the vat on rolls, and the fibers are washed off by a shower pipe 
at a convenient point, or are scraped from a couch roll, as at 22. 
In another type, the collected fiber is blown off the face of the 
cylinder by means of a current of compressed air, which is 
discharged through a perforated pipe in a tangential direction 
against the outside of the cylinder. 

Fig. 11 shows a cj^Hnder revolving in a vat of white w^ater 19. 

By means of interior air-tight compartments, w'hich are connected 

to a suction pump, the water is pulled thi'ough the wire, and the 

fibers are left behind on the surface of the 

wire when the air-tight compartments are 

under water. At a certain point, 18, when 

these air-tight compartments are out of the 

water, they connect with the discharge of an 

air pump, and the fibers are blown off the 

surface of the wire, to slide dow-n the doctor 

Fig. 11. 6. This type of machine is also used to 

thicken pulp. 

23. In all these machines, with the exception of the save-all 
where the felt is used, there is Httle or no salvage of the finer 
fibers and of the filling materials, such as clay, because these 
find their way through the mesh of the cylinder-wire covering. 
Where the felt is used, the loss due to the wear of the felt and to 
the expense of attendance (this latter item being chargeable to 
all types of save-alls) becomes an important consideration. 

24. Settling Tanks. — A very important type of save-all that 
is largely used in book-paper mills is called the settling tank; 
its first cost is expensive, but this is more than compensated for 
by the small cost of operation, upkeep, and repair, with no parts 
to wear out or require renewing. 


To take care of all the white water from a pulp or paper mill, 
the settling tanks must be of large proportions, in order to give 
all the white water sufficient time to stand long enough to settle. 
In some cases, the white water is distributed around an annular 

Fig. 13. 

Fig. 14. 

Fig. 15. 



Fig. 16. 

Fig. 17. 

trough, Fig. 12, running on the outside circumference of the tank. 
When full, this annular trough allows the white water to flow 
slowly over into the tank, so as to prevent any undue agitation 
and permit the maximum settling effect. This type of save-all is 


made conical in shape, the apex of the cone being the lowermost 
point, at which the sediment is removed through a valve. 

Fig. 13 shows a more modern type, in which the white water 
enters at the center, and flows outwardly into a series of annular 
troughs until it reaches the outer trough, where the solids finally 
settle in the bottom of the inverted cone. 

The settling type of save-all possesses the advantage of 
allowing the savings to be pumped back into the sj^stem, thus 
eliminating the labor involved in the save-alls previously 
described, where the savings are so thick that it is necessary to 
shovel them into trucks, from which they must then be forked 
into the beaters. Settling tanks must be large enough to permit 
their uninterrupted operation, in order that the white water may 
flow continuously into the tank, while the savings and clear 
water are flowing away continuously and separateh\ This 
requires that the tanks be about 20 feet in diameter and that the 
cone be about the same height, though even larger dimensions 
are preferable. The settling tank does not work right until it 
becomes full of white water, when the incoming water comes 
quickly to rest on top of the large body of water beneath it, and 
then the suspended matter begins to settle at once. 

25. Inclined-Wire Save-Alls. — A commonly used type of save- 
all, which is made in many different forms, is easily built in the 
mill, and requires little or no power to drive it, is an inclined 
screen, of fine mesh wire, which is sometimes given ashght motion; 
it requires only intermittent attention, which involves merely the 
pouring of the white water. This type needs practicalh^ no 
attention at all, since the savings can be pumped back into the 
system in the same manner as in the settling tank, the wire screen 
replacing the settling action. It also has the advantage of low 
first cost. Figs. 14-17 show diagrammatically four forms of 
this type. 

26. Fig. 14 shows the Whitham type. The diameter of the 
cone at the top is about 11 feet the diameter of the opening at the 
bottom is about 2 feet and the height of the cone is about 10 feet 
The speed of revolution, about 6r.p.m., is not important; it simply 
revolves fast enough to allow the showers to clean the face of the 
wire. While the wires should be about 120 mesh, to save the 
maximum of fiber, they are often as coarse as 80 mesh, or, even, 
60 mesh. 


A save-all of this type, and of the dimensions given, can handle 
about 400 gallons of waste water per minute, which is the average 
amount of white water from a paper machine making 50 tons of 
paper per day of 24 hours, about 4500 pounds of paper per hour. 
The two figures are given, because the hourly figure is the max- 
imum output, while the daily figure is the average output 
when allowance is made for breaks, etc. 

The save-all shown in Fig. 15 is similar to that of Fig. 14, 
except that the cone is inverted from its former position, and the 
showers are on the outside, the water flowing on the outside of the 
cone instead of down the inside, as in the case of the former. 

The most important thing in connection with an inclined save- 
all is the cleaning of the wire. If the cleaning is intermittent, it 
should be done at least once every 8 hours. 

27. Fig. 16 shows the Nash type of save-all, in which the cone is 
replaced by a flat vibrating screen, situated at such an angle that 
the entering water flows down and through the screen; the sav- 
ings are left on the surface, to be washed off by a shower pipe. 

The Shevlin type of save-all is shown in Fig. 17. It consists of 
a revolving, fine-wire-mesh covered cylinder that contains a 
revolving worm. As the white water flows in at one end, the 
clear water escapes through the wire mesh, and leaves the savings 
in the interior; the screw (worm) gradually forces the savings 
along the interior of the cylinder until they are delivered out at 
the other end, where they fall into a suitable receptacle, from 
which they are pumped back into the system. 

28. Save-Alls as Filters. — The savings and rejections may be 
pumped separately into the system at convenient points, or they 
may be permitted to run to waste, as desired. The save-all is 
sometimes used for straining or filtering purposes, in which case, 
the clear water that passes through the wire can be pumped into 
the water system that serves the mill, and the savings may be 
dirt that is allowed to fall from the screen save-all to waste. 

The wire mesh that is used in the construction of these save-alls 
must be well supported with wire of about 14 mesh, to keep 
in shape; the only part that requires renewing is the fine 
wire, as it wears out; this is a good place to make use of old 
Fourdrinier wire. The capacitj^ of the wire type of save-all, 
when used as a filter, is practically unlimited; a save-all of the size 
mentioned in Art. 26 will filter 2,000,000 gallons of water from all 


solid impurities in 24 hours, and it will supply water for paper- 
machine showers and for similar purposes. The power required 
to drive this save-all is very small, a maximum of 3 h.p. being 


29. Construction. — Rifflers, or sand traps, are wood troughs 
through which the stock flows from the regulating box to the 
screens. They vary in size and length, and in shape, according 
to the capacity of the machine and the relative position of the 
regulating box with respect to the screens. Note the position of 
the riffler in Fig. 2. 

The bottom of the trap (riffler) is divided into sections by 
transverse strips of wood, which are frequently so inclined that 
their faces lean against the flow of the stock; this helps in the 
retention of dirt, or sand, as it sinks to the bottom of the riffler. 
In some narrow boxes, the wood strips are replaced with strips of 
zinc, slipped into slots in the sides of the trap; these can easily be 
removed for cleaning. The depth of the riffler, or sand trap, is 
from 18 to 20 inches, and the width is from 18 inches to 8 feet. 
The narrower sizes are usually of greater length, say from 30 to 50 
feet; while the rifflers called button catchers may be longer, even, 
than 50 feet, when they are used to catch stitching wires in mills 
that prepare the stuff from old magazines. The wider traps are 
seldom over 15 feet long, being used in the preparation of fine 
writing and bond papers. The bottom of the trap is sometimes 
covered with old felt, to catch and hold the dirt, but this is of 
doubtful value. The rifflers should be carefully cleaned whenever 
the mill is shut down. If felts are used on the bottom of the 
riffler, they should be nailed down between the slats and carried 
up the sides, so that no dirt or stuff can accumulate underneath 
and break away at intervals, to cause breaks on the machine. 

For the purpose of controlling the amount of water in the stuff, 
there may be two pipes at the inlet to the riffler, one for water 
and one for pulp from the regulating box, when the stuff is not 
diluted in the regulating box or in a special mixing box. 

30. Two-Run Riffler. — Fig. 18 shows one type of riffler, or 
sand trap. The mixed water and fiber flows into the riffler 
through pipe A, and the pitch (slope) of the bottom of the riffler 
is only about 1 inch in 14 feet. Observe the shape of the strips J5 


that catch the heavier particles of sand. This riffler is divided 
into two runs by the central dividing board D, the total length of 
run of the stock being about 28 feet, and the width of each run 
being about 18 inches. The discharge pipe C leads to the screens. 
When the riffler is to be cleaned, the discharge pipe C is dis- 
connected, the supply pipe A is put to one side, and the riffler is 
turned on its side, or even upside down, so a hose can be played 
into it and the dirt washed out. By turning the handle H, the 
worm W turns the worm wheel Wi, and moves the riffler over as 
far as is required. The worm wheel Wi is keyed to the gudgeon 
(journal) G. 

Fig. 18. 

Other types of rifflers are illustrated and explained in . the 
Section on Treatment of Pulp, Vol. III. Since rifflers are often 
made at the mill, local ideas and conditions may affect their con- 
struction. The student should refer to Figs. 1 and 2 constantly, 
to familiarize himself with the circulation of the stuff from the 
stuff chest until it becomes stock on the rifflers and is delivered to 
the machine. 

31. Riflflers with Electromagnets. — Paper stock that is pre- 
pared from rags, especially if overalls are used, is likely to contain 
small particles of iron. This may also occur when waste papers, 
stitched with wire, are used. Particles of iron may likewise be 
present by reason of the abrasion of beater and Jordan bars. 
Such particles can be almost entirely removed from the diluted 
stock by placing an electromagnet across the riffler, just before 
the stock goes to the screens. When this is done, it is a good 
plan to make the riffler a wide, short box, in which the magnet is 



placed, in order to have a shallow stream of water flowing over 
the magnet. A good installation is shown in Fig. 19. 

Here ^ is a stream of stock in the riffler 5; C is an adjustable 
baffle; arrow D shows the direction of flow of the stock; E, E are 
magnet pole pieces; F, F are magnet coils; G is a yoke connecting 
the two pole pieces; // is a wood support for the extractor; and 

Fig. 19. 

K and L are the lead wires. A plugged hole in the bottom or 
side of the magnet affords an opening for cleaning, when the 
current is off. Direct currrent is equired for an electromagnet. 


32. Diaphragm Screens. — Before the paper stock finally 
enters the flow box, or head box, as it is sometimes called, ready 
to flow onto the wire of the paper machine, it is screened, for the 
purpose of removing as much as is possible of the dirt, lumps, 
slivers, etc. that may be present, and which have resulted from or 
have escaped during the process of preparation. Both the flat, 


or diaphragm, and the rotary types of screens are used at this 
stage of manufacture. In either case, a difference in level 
between the inside and the outside of the screens causes the water 
in which the fiber is suspended to pass through a slotted or 
perforated plate. 

In Fig. 20, the diaphragm screen is made to take 10, 12, or 14 
plates, usually of bronze, which are 12 inches wide, 43 inches long, 
and about | inch thick. These plates 12 form the top of a shallow 
box, the bottom of which is made up of a series of rubber dia- 
phragms 22, which are supported on boards 14 and are separated 
by wood spacers 21, which, together with the strips 30, support the 
plates. The top of this shallow box is the bottom of the screen 
box, the sides and ends of which are numbered 10 in the 
illustration. The screen box rests on the frame 18, to which the 
diaphragms are nailed. The box and frame are clamped together 
by long threaded bolts (screen bolts) in such a manner as to 
make a tight joint all around. Two socket joints are provided 
on one side, so the box can be raised at intervals and washed with 
a hose. The diaphragms, which give the screen its name, are 
fastened by air-tight joints to the sides and ends of the box and 
to the cross beams 19. Rods 5, attached by blocks 23 to the 
centers of the diaphragm boards 15, and bearing at their lower ends 
a hard-wood toe block 7, ride cams 8, which have three or four 
corners. The cams are mounted on a shaft 2, which revolves at 
125 to 175 r.p.m., thus agitating each diaphragm either three or 
four times for each revolution of a cam. The cams are so 
mounted on the shaft that their strokes alternate with one 
another. The hard-wood blocks, usually maple, are held by 
clamps 9; they are removable, since they require replacing as 
they wear out. The blocks are restrained from jumping away 
from the cams by the springs 27 and 28, and by the adjusting 
nuts 4. 

33. The size of the slots in the screen plates depends upon the 
land of paper being made, their width ranging frorn 8 to 25 
thousandths of an inch (0.008"-0.025"); they are referred to as 8 
cut, 25 cut, etc. The slots are wider at the bottom than at the 
top, and are cut about 4 or 5 to the inch; their length is about 4 
inches. The screen is made with an adjustable dam 31, 32 at the 
outlet 16, to permit complete control of the level of the stock 
relative to the plates. The position of the plates being fixed, the 
use of the adjustable dam board 32 allows the operator to back 





up the water and stock under the plates until the screening action 
is satisfactory. If the stock level is too high, the diaphragm will 
shoot the stock back through the plates; if the level is too low, 
the capacity of the screen is decreased, as there must be enough 
surge to keep fibers from settling thickly on the slots. The 
operator should adjust the dam while he looks down on the screen, 
while the screen is in operation. Sometimes a variation in the 
sizes of the slots in the different plates is successfully used to 
increase the capacity of a screen. When this is done, the oncom- 
ing stock is forced to foUow a definite path, mapped out with 
baffles. The plates hadng the larger slots are near the recei^-ing 
end, where the stock flows freely and rapidly; the plates ha^-ing 
the smaller slots are at the other end, where the flow of the 
stock is retarded and the stock has nearly finished its 
journey. Stock is nearly always dehvered to a screen at one 
end, there being a slight slope downwards of the plate surface to 
the other end. 

Screens should always be kept clean; otherwise, they soon 
become filled with stock. This not only decreases the capacity 
of the screen but it also increases the danger of lumps of stock 
accumulating. In time, these lumps get into the flow box 11, 
Fig. 20, from which they find their way to the paper machine 
and are a frequent cause of breaks. 

34. Care of Screens. — The screen plates are often ruined by 
careless workmen during the operation of cleaning. Walking 
on the screens in hobnail boots (which catch in the slots), and 
banging the plates with hammers or pieces of belting, may force 
through the plates the material to be removed; but it is very 
likel}- to injure the plates, and the slots may be appreciably 
enlarged. The only right way to clean screen plates is to raise 
the screen and patiently clear each slot with the cleaning tool 
that is suppUed by the screen-plate makers, and which is just 
large enough to go into the slots. The plates should then be well 
washed with a hose. 

The screens should be well washed at least once a week; this 
means that the boxes must be Hfted out, the slots cleaned, and 
the interior of the diaphragms and aU inner parts of the screen 
boxes thoroughly cleaned of all slime and traces of old stock. 
If this be not done periodically, the dirt, shme, and accumulations 
of stock win get on the wire and cause many unnecessary breaks 
and much spotted paper. The slime that coUects lq the screens 


is a peculiarly fertile source of trouble; it forms a transparent 
spot, which will generally become a hole somewhere on the 
machine. These slime spots are a sign of dirtj^ screens. 

It is well to have a set of boxes for each screen, with plates 
of different cut. It may even be desirable to have a duplicate 
box for each screen, to allow a clean screen to be put in place 
quickly, especially when using long rag stock. Care should be 
taken that the screen diaphragms work right; see that the outlet 
dams are properly adjusted, and be sure that the hard-wood 
blocks do not ride, for, if they do, they cannot give the diaphragm 
the proper range of action. 

The use of a shower of water to wash the large slivers, shives, 
and dirt to the lower end of the screen is preferable to, and gen- 
erall}^ quite as satisfactory^ as, the use of scrapers. If scrapers 
are used, they should be made of softer material than the metal 
of the screen plates. The plates should be carefully handled and 
cleaned; and, if the slots are enlarged by reason of excessive 
cleaning, the plates should be discarded. Screen-plate manu- 
facturers can re-cut old plates to some standard slot size. 
The screws must fit in the spacer pieces and sills, so each screen 
plate may be rigidly held in its place. It is almost impossible 
to keep screwed screen plates in condition after the sill screw- 
holes get worn; in any case, there is a tendency for small screws to 
get lost or badly strained when the screens are cleaned. There 
are many designs of screwless screen plates, which are fastened 
in place by beveled or rabbited cleats that fit specially edged 
screen plates. If not too complicated, all such designs are 
superior to the screw type. 

Care should be taken to screw or clamp securely to the screen 
frame the top box that carries the plates, using a good water- 
tight packing. The diaphragm screen is still very commonly 
used, in spite of many obvious drawbacks. 

35. Rotary Screens. — Many paper makers prefer rotary 
screens because, with this type, it is possible to keep the screen 
plates continuously clean by means of a good shower. It is 
only of late j'^ears that rotary screens of simple design and heavy 
construction, qualified to give large capacity and long service, 
have been available. Several makes of rotary screens that are 
proving satisfactory in operation are now on the market. They 
are of two types ; namely, the inward-flow screen, and the out- 
ward-flow screen. Both have their own peculiar method of 


agitating the stock, to assist it in flowing through the plates and 
in preventing the settKng of fiber. 

The inward-flow type of rotary screen is naturally of greater 
capacity than the outward-flow type, and it is best adapted to 
screening dirty stock. It is used for newsprint, book, sulphite 
bonds, bag, wrapping, board, roofing, and coarse papers generally. 
The outward-flow screen is better suited to the making of fine 
papers, such as ledgers, fine writings, and bond papers containing 
a large proportion of rag stock. 

36. Inward -Flow Rotary Screens. — Fig. 21, is an end view 
of a frequently used inward-flow rotary screen. The stock 
enters through flow boxes A and B, both being placed 
above the vat and discharging downwards against a revolving 
cylinder C. The stock passes through the screens that form the 
shell of the cylinder, and it then flows through an open journal to 
a discharge box at the rear 
end, which is connected to 
the flow box of the paper 
machine. There is a dif- 
ference of level between the 
stock that is inside and that 
which is outside the cyl- 
inder. Stock that will not 
pass through the screens 
settles in drain E, from 
whence it flows to the 
auxiliary screen. The lat- 
ter is a specially designed, 
small, flat screen, where the 
good fibers are washed 
through and recovered. 
The slots in the revolving screen are cleaned by the shower pipe 
H. The pan / serves as a guard against splashing, and tray J 
catches the water that strikes the cylinder and falls back. The 
bodj' of the vat K is made of boiler plate, and is copper hned; it 
is supported by two semicircular brackets L, one end of which 
is, in turn, supported by two vertical plate springs M, and the 
other end is supported by a double pivot A^ From this pivot, 
the shake arm extends to the eccentric P, which runs at about 
350 r.p.m. This vibration of the screen tends to churn the stock 
and urge the fibers through the slots. 

Fig. 21. 




37. Another type of inward-flow screen depends for agitation 
on a difference of shape between the rapidly revolving drum and 
the interior of the vat. Under certain conditions, this causes a 
series of varying suctions and pressures in the screen cylinder, 
which reproduces, in a measure, the action of the diaphragms in 
the flat screen, A screen of this type is shown in Fig. 22, and it 
requires no eccentric or mechanical vibratory motion. The 
agitation of the stock is caused by the revolving of the polygonal 
drum A at a higher speed and in a direction opposite to that of 
the screen cylinder B. Referring to the diagram, Fig. 22, the 

distance DH is less than the dis- 
tances FG and EK. When drum 
A revolves in the direction of the 
arrow and the point D falls on a 
radius drawn through E, the space 
between E and the cylinder will be 
smaller than when the drum is in 
the position shown in the cut, and 
a pulsation outward will take place. 
When the point C passes the point 
on the radius indicated by the point 
"^^°* ^^" F, and goes on to the position of 

the point D, the space between the drum and the cylinder becomes 
larger, and an inward suction takes place. In other words, the 
level of the stock outside of the drum is caused to rise and fall 
slightly, provided the drum is not entirely submerged, which 
creates a suction that causes the stock to flow into the drum. 

38. There are several makes of screens in which the stock is 
agitated by means of immersed plates. In one, a vertical plate 
on either side of the cylinder is moved by rods that pass through 
rubber diaphragms in the side of the vat. In another type, a 
horizontal plate under the cylinder, and bent concentric with it, is 
vibrated up and down by an eccentric having an adjustable 
throw. Still another make has a plunger, with a reciprocating 
motion, in a chamber below the screen; this creates suction 
alternately on each end of the screen cylinder. 

39. Outward-Flow Screens. — A good example of the outward- 
flow screen is shown in Fig. 23 ; it is designed and built for screen- 
ing high-grade rag and long-fibered slow stocks. The stock 
enters the cylinder through pipe M, at one end; it then drops to 


the bottom of the cyHnder, passes through the slots into the 
trough N, from whence it goes to the paper machine. The 
rejections are carried up with the revolving cylinder A, and are 
washed out through the discharge pan Q by the shower V. 
The shaft S, driv^en by eccentric H, is fitted with a lever F at 
either end; it jerks the straps B, on which rest circular projections 
C of the cylinder A, which would be journals if they turned in 

bearings. This jerking of the straps 
vibrates the cylinder, and it hitches 
it around at the same time. 

40. Another mechanism, by 
means of which the screen itself is 
made to vibrate, is shown in Fig. 
24, where S is the screen and T is 
the vat. The screen is carried on 
an arm A , which is pivoted about a 

Fig. 23. 

point P; to the other end is attached a pawl C, which engages 
with an interrupted cam, or ratchet wheel W. As the ratchet 
wheel revolves in the direction indicated by the arrow, the pawl 
is lifted; and this, in turn, lifts the arm and screen. When a 
point of the tooth is passed, the pawl, arm, and screen fall; this 
jars the screen, and the jar loosens any fiber that may have 
clogged in the screen. The screen is revolved by a ratchet wheel 
that is attached at one end of the cylinder. 

41. A popular Enghsh screen dithers (vibrates) the cylinder 
by means of an adjustable, rotary-eccentric, center bearing at 
one end. The shaft, which makes GOO r.p.m., carries in an 
eccentric position a circular hub that turns in a Hoffman ball 
bearing, which is attached to the spider that supports one end of 
the cylinder. 




42. Outward-flow screens are thus seen to require that the 
screen cyHnder be agitated to assist the flow; but with inward-flow 
screens, there are also available several other methods of agitat- 
ing the stock. An outward-flow screen is cleaned by a shower 
pipe outside the cyhnder. 

The principal differences in rotary screens lie in ruggedness 
and simplicity of design, difference in the methods of creating 
suction and agitating stock, and in the method of removing the 
rejected stock. 

A very good discussion of screens is given in the Section on 
Treatment of Pulp, Vol. Ill, 



43. Robert's Invention. — The process of making paper by 
hand, which was the method in universal use until the invention 
of the paper machine by Louis Robert, in France, in 1799, is 

Fig. 25. 

described in the Section on Handmade and Special Papers, Vol. 
V. For both handmade and machine-made paper, the prepara- 
tion of the stock is the same, and has been fully explained in 
previous Sections. 

The first paper-making machine that was designed by Robert, 
see Fig. 25, consisted of an endless wire cloth A, which passed 
between two rolls B and C. The position of B was fixed, while 
C was adjustable, so the wire could be stretched. The beaten 
pulp in vat D was thrown up by a revolving fan E against the 
baffle plate F, which distributed the pulp and water in an even 


stream on the moving surface of the wire cloth. As the wire 
cloth A traveled slowly forward, the water passed through the 
wire, while the small squeeze rolls G completed the preliminary 
de-watering. The receiving roll H reeled up the wet sheet until 
a sufficient length had been obtained, 50 feet being generally 
accepted as the practical limit. The roll was then removed, the 
paper unwound, passed through some press rolls, and hung up 
to dry. A working model of this machine was made; but, as is 
always the case with a new design, it was not perfectly satis- 
factory. Robert was granted a bounty of 8000 francs to assist 
him in his studies and experiments; and he sold his interest in 
his patent, and his model of the machine, to his employer, M. 
Leger Didot, of Essones. 

44. Early English Patents. — M. Didot realized the greater 
possibility of successfully perfecting such a machine in a country 
free from governmental strife, and doubtless strongly urged 
thereto by his brother-in-law, John Gamble, an Englishman, 
he sailed for England in the summer of 1800. Didot had some 
mechanical ability, and it is possible that some improvements on 
the original machine were made by him before leaving France, 
In England, Didot was fortunate in securing the help of Mr. 
Bryan Donkin, a man well qualified by his mechanical training 
to perfect the details of a machine of this type. 

45. On April 2, 1801, English patent No. 2487 was granted 
to John Gamble for the improved paper machine, the title of the 
patent being: "An invention for making paper in single sheets 
without seam or joining from one to twelve feet and upwards 
wide, and from one to forty-five feet and upwards in length." 

Further improvement in design finally resulted in a new patent, 
No. 2708, dated June 7, 1803, issued by the English govern- 
ment to John Gamble for "Improvements and additions to a 
machine for making paper in single sheets without seam or 
joining from one to twelve feet and upwards wide and from one 
to fifty feet and upwards in length." In the autumn of the year 

1803, the first paper-making machine ever to be built and suc- 
cessfully operated, was started in Frogmore, England; in 

1804, another successful machine, practically a duplicate of the 
first, was put into service at Two Waters, England. 

46. In 1804, Messrs. Henry and Sealy Fourdrinier purchased 
the remaining interest of Didot and Gamble in the improved 




Robert machine. Henry Fourdrinier was granted patent No. 
2951, on July 24, 1804, for "The method of making a machine 
for manufactming paper of indefinite length, laid and wove with 
separate molds." On August 14, 1807, an Act of the British 
Parliament gave an extension of the patent rights obtained by the 
Fourdriniers for invention of making paper by machinery. In 
this Act, the machine described by John Gamble in the specifica- 
tions of his patents, Nos. 2487 and 2708, together with the added 
improvements, were all fully described and illustrated by 

During the year 1808, John Gamble assigned to Messrs. 
Fourdrinier all his rights in the patents as extended by this Act 
of Parliament, thus making them the sole proprietors of the 
patents covering the only successful paper-making machine in 
existence. So the machine invented by Robert, promoted by 
Didot and Gamble, designed by Donkin, and financed bj'- the 
Fourdriniers, came to be known, and continues to be known, as 
the Fourdrinier machine. 

47. The Donkin Machine. — The fust Donkin machine is 
illustrated in Fig. 26. The mixture of pulp and water, kept in a 
state of agitation, flowed from the vat A, which is like a modern 

Fig. 26. 

flow box, through pipes and onto the endless wire cloth B, 
between the endless deckles C. The wet sheet of paper, having 
lost its excess of water, was passed between the squeeze or 
couch rolls D, as in the Robert machine, to be further de-watered; 
but, in this case, the work was better accomplished by reason of 
the traveling upper felt E. This felt, the ancestor of the couch- 
roll jacket, also improved the firmness of the wet paper. The 
paper then traveled to the press rolls F and G, and then was 
finally wound up on the reel //. 

48. First Machines in America. — The first Fourdrinier 
machine in the United States appears to have been imported from 


England, in 1827, by H. Barclay, of Saugerties, N. Y. This 
machine was a Donkin machine, 60 inches in width. A second 
Fourdrinier machine, 62 inches wide, was installed in this mill 
in 1829; but the second machine to be erected in the United 
States was imported from England and set up in the Pickering 
Mill, in Windham, Conn. This latter machine was copied by 
Phelps and Spafford, of Windham, and soon after that by Howe 
and Goddard, of Worcester, Mass. The Fourdrinier machine 
did not come into general use until several years after its first 
successful operation; even in England, only ten machines were 
made between 1803 and 1812, and only twenty-five more were 
built in the next decade. It was not until about 1830 that this 
great invention finally came into its own. 

It is noteworthy that, in the early daj^s, the cylinder machine 
patented by John Dickinson, in 1809, received more attention 
from mechanics and inventors in the United States than did 
the Fourdrinier. The supporting of the wire by table rolls in 
the Fourdriniers, and the use of these rolls in hastening the 
evacuation of the water, does not seem to have received 
the attention these features merited; and, in so far as the writer 
can find, no patents were issued covering these points. In fact, 
it is doubtful if many paper makers today realize to an}^ greater 
extent than did the earlier generation the importance of the 
action of the table rolls. 

49. Improvements in the Earlier Machines. — In 1826, Mr. 
Canson, in England, applied suction pumps to the Fourdrinier 
machine, to cause a suction underneath the wire on which the 
paper was formed, in order to assist in the removal of water. 
This invention really was an adaptation from the Dickinson 
cylinder machine. 

It was not until the years 1889 and 1890 that the modern 
machine was perfected, which, with all its improvements, is 
essentially the same machine as the original of Fourdrinier and 
Donkin, with the addition of the cone drive and the steam-drying 
cyhnders. Among the older paper makers, there still lingers 
the memory of when the paper dryers were headless cylinders, 
with a wood fire in each one. Steam cyhnders for drying paper 
were first used by Crompton in England, in 1823. 

The dandy roll was invented by J. Marshall in 1826. In 
1820, Barrett invented a method of making rolls true by grinding 
them together, using water and emery. 




50. General Data. — A skeleton outline of the Fourdrinier 
part of a modern paper machine is shown in Fig. 27. The flow 
box, or head box, 1 receives the prepared stock, which is screened 
and mixed with a large proportion of water. On a slow-speed, 
fine-paper machine, the contents of the flow box will consist of 
about 1% of fiber and 99% of water; while in the high-speed, 
news machine, it will consist of about |% of fiber and 99|% of 
water, a ratio of water to fiber of 199 to 1, say 200 to 1. The 
stock flows from the flow box 1 to the apron 2, and from thence, 
to the wire 3, which moves on from the breast roll 4 to the support 
of the table rolls 5. 

51. Course of the Wire. — The wire, partly hidden by the 
shake rails, travels from the breast roll 4 over the table rolls 5 
and suction boxes 6, under dandy roll 7, over guide roll 8, between 
couch rolls 9 and 10, and comes back over wire roll 11, under 
stretch roll 12, over and under more wire rolls, and so back to the 
breast roll 4. The couch roll 9 is driven mechanically; this, in 
turn, drives the wire, which acts as a belt and drives the other 
rolls. The guide roll may be outside and under the wire near the 
breast roll. The table rolls 5 are supported by the shake rails 13, 
which carry bearings that are so adjustable that the rolls just 
touch the wire without lifting it. The shake rails up to the last 
table roll, together with the breast roll and several wire rolls, 
are supported on the frames K, which are pivoted at H, and are 
raised or lowered at the other end by some device, such as the 
screw-and-worm gear W. Sometimes the pivot is situated 
beyond the suction boxes. A shaft that extends across the 
machine connects the front and back gears, which move both 
sides the same amount. The shake rail is jointed just past the 
last table roll, at H, so the breast roll and front part of the wire 
can be given a jerky, horizontal motion, or shake, which assists 
the fibers to interweave in all directions, instead of flowing 
parallel to the direction of the wire travel. 

The rubber deckle straps D, which have a square cross section, 
ride on the wire and form a tray for the paper stock, returning 
over the deckle pulleys E and through the wash trough F. 




While the stock is being carried along 
by the wire, most of the water passes 
through it, under the influence of gravity 
and by the action of the table rolls, and 
flows into the white-water trays or boxes 
B (sometimes called save-alls), and 
usually goes to the white- water pump; 
more water is removed by the suction 
boxes 6, and a little more still by the 
couch rolls 9 and 10, which also press 
the fibers together. 

52. Taking the Paper from Wire to 
Felt. — The paper is now sufficiently 
formed and firm enough to be carried 
to the first press felt. This latter oper- 
ation is simplified by cutting the sheet 
into two strips, one about 1 or 2 inches 
wide, by means of the cut squirt C, 
which is simply a nozzle that directs a 
fine jet of water upon the soft web of 
paper. The reason for cutting the strip 
is that the machine tender can more 

^^rip , 

Fig. 28. 

readily pick up this ribbon than he can 
pick a wide piece off the wire : he lays it 
on the first press felt; and when this strip 
is successfully carried onto the wet felt, 
the cut squirt is pushed across the 
machine, carrying with it its feeder hose, 
which is supported in a long slotted pipe 
that stretches across the machine, thus 
cutting the paper all the way across. 
Since the paper is travehng toward the 
couch rolls at the same time that the cut 
squirt is pushed across it, the paper is 


cut diagonally, about as indicated in Fig. 28. It is evident 
that if the narrow strip be on the wet felt, the rest of the paper 
must also follow it into place. 

If the machine is not equipped with a cut-squirt, the paper 
is placed on the press felt thus: The machine tender pats the 
edge from the wire, with the palm of his hand or with a piece 
of wet broke, which he slaps down so as to create enough suction 
to lift the paper. This tears a narrow strip, which he widens 
by lifting it skillfully at an angle. The back tender then tears 
off a bit of the inside edge and pulls his part toward the wire 
and also toward the back of the machine. This is repeated till the 
first narrow strip going to the felt is widened to the whole width 
of the sheet. It is a very delicate operation, requiring skill and 

As it leaves the lower couch roU, the return wire passes under 
a strong shower, which is situated over wire roU 11. If the paper 
is not 3^et ready to be passed onto the wet felt from the wire, or 
if it be broken between the couch rolls and wet felt, it wiU stick 
to the wire. At roll 11, all paper not washed off will leave the 
wire and will stick to the smooth surface of the roll. The doctor, 
or scraper, 14 scrapes all the paper off roll 11, so that it falls into 
the white-water pit, or box, underneath the wire at this point. 
If lumps stick to this roll, they may cause bulges in the wire 
and produce much trouble. The wet-paper broke collected in 
this box, or pit, flows to the save-alls, to the white-water pump 
suction, or to the beaters; in some mills, it goes to waste. Cir- 
cumstances decide what shall be done with it. 

53. Up to this point in the description of the Fourdrinier, no 
mention has been made of the slices, which are situated near the 
apron and which control the depth of the stock on the wire. 
These, together with the guard board L, the stretch roll 12, the 
wire rolls, the Fourdrinier elevating mechanism K, and the 
save-all, or white-water, boxes 5, will all be fully described later. 
The dandy roll 7 (also shown in detail in Fig. 41) rests lightly 
on the wire where the wire passes the first or second suction box. 

The pressure couch rolls 9 and 10 are sometimes replaced by 
one suction roll, which is described later. The wire is kept as 
clean as possible by continuous showers of fresh water, thrown 
on it by the shower pipes S. Spray pipes T are placed over the 
flow box and apron, to break down with fine sprays of fresh 
water the froth that is sometimes formed. 




54. Right- and Left-Hand Machines. — A paper machine is 
either a right-hand or a left-hand machine. If one stand at the 
dry, or calender, end and look toward the wet end, a right-hand 
machine will have the drive on the right side of the machine, 
while a left-hand machine will have the drive on the left side of 
the machine. It will be noticed that, on a right-hand machine, 
the machine tender lifts the paper from the wire to the first felt 
with his right hand; and uses his left hand on a left-hand machine. 
The left side of a right-hand machine, or the right side of a left- 
hand machine, is called the front, or tending side. 



55. The Flow Box. — Some paper makers prefer to call this 
part of the machine the head box or breast-roll feed box, because 

Fig. 29. 

the box at the side of a flat screen is also sometimes called a 
flow box. Its purpose is to convert the rapid flow of stock in 
pipe G, Fig. 2, into a smooth, flat stream that will flow out evenly, 
without eddies, to* the [full width desired on the wire. It also 
provides a head that will be sufficient to cause the stock to 
emerge at a speed that approaches that of the wire. 

There are many designs of flow boxes, the tendency being 
toward simplicity, as shown in Fig. 29. Here the stock enters 
at A, and as it fills the flare of the box, its velocity diminishes. 
The stock rises in an even flow; it overflows at B, controlled by 




the gate G, into the white-water box W, Fig. 2, or to waste, until 
the machine tender is ready to start the wire. An opening V 
serves as a washout for cleaning. 

56. Flow Boxes with Baffles. — On some machines, the flow 
box has a series of baffles, as shown in Fig. 30, to eliminate eddy 
currents. The stock enters at A, passes up over the first baffle, 
under the second, and then onto the apron D, through slot C. 
The edges of baffles should be rounded. Outlets V are pro- 
vided at the bottom of each division, which discharge to the sewer, 
to the white-water tank, or to the pump intake; this takes care of 

Fig. 30. 

the stock before the wire is started, and it prevents flooding the 
wire in case of a sudden shut down. Parts G and S are explained 
later; they apply particularly to news machines. 

57. A row of holes or a slot C, Fig. 3 1 , and (6) , Fig. 29, sometimes 
controlled by a gate, feeds the stock to the machine. The space 
between the flow box and the wire is bridged by an apron or apron 
cloth E; this is supp:rted as far as the breast roll F by the apron 
board D, which is fastened by brackets to the front of the flow 
box. A part of the box front, or merely the board and brackets, 
may be made adjustable, so as to respond to any change in the 
inchnation of the wire. On some machines, the apron board, and 
on some the whole flow box, is attached to the Fourdrinier part. 

The apron E may be of oilcloth, fabrikoid, or rubber-coated 
cloth; it must be thin, flat, and without wrinkles, and it must fit 
snugly to the deckle frame; it must form a water-tight connec- 
tion, and one that will permit adjustment of deckles when the 




width of the sheet is to be altered. This last is difficult, especially 
if the Fourdrinier frame is shaken. 

58. Putting on the Apron. — The apron is put on as follows : A 
strip of dryer felt M, wide enough to reach from the opening of 
the flow box to within about 3 inches of the first slice L, is so laid 
down that it reaches from edge to edge of the apron board and 

Fig. 31. 

of the wire W; on top of this is laid an apron-cloth strip E, wide 
enough to reach from the flow-box opening to within 1 in. of the 
slice. (Some machine tenders bring the edge to the slice.) 
Both felt and cloth are tacked to the apron board, or are held by 
a strip of brass, screwed down; tacks are dangerous. 

The end of the apron should not come directly over a table 
roll, since the deckle strap rides the edge and will cause wear of 
the apron and make bad edges on the paper. Side pieces P, 
of brass or other suitable metal, are bent and fastened to the face 
of the flow box by bolts or thumb nuts /; there are slots in the 


metal that permit side wise adjustment. The side pieces form 
the sides of the stock-channel to the slices; they are fastened to 
the inside of the deckle frame H, on either side of the machine, 
just inside the deckle straps. The edges of the apron E, on 
each end, may be carried up straight and held tight against the 
side plates by a strip of metal S, inside plate P, held in place by 
a clamp K at the flow box and by another clamp K2 at the deckle 
frame H; this clamp grips the side plate, apron, and inside plate 
to the deckle frame. 

Sometimes the apron is allowed to stay flat, and the joint is 
made at each side by a separate piece of apron cloth, about 18 
inches wide, which is allowed to lap over on the apron; a piece of 
wool felt between the two pieces of apron cloth, sewed to the 
upper one, helps to make a tighter joint. Sometimes a strip 
of metal is laid flat on this joining piece, to get a square corner; 
this, however, is considered poor practice. 

59. Changing Width of Paper Sheet. — When making only 
a small change in the width of the sheet, the clamp on the deckle 
frame is loosened until the deckle is shifted, the slack of the 
apron is taken up, or more let out, and the plates are again 
clamped in place. For a large change in width, it may be neces- 
sary to shift the connection at the flow box. The flexibility 
of the side plates provides for the shake movement. 

60. New Design of Flow Box. — There are some new designs 
of flow box, which operate under a considerable head and have 
a spout that is designed on hydraulic principles; these boxes 
deliver a smooth current of stock to the wire, without eddies or 
ripples, and do not have an apron. The most recent develop- 
ment is embodied in the newest newsprint mills in Canada, where 
the front of the flow box is formed by the slice (see Art. 72). 
In Fig. 30, the slice S forms the front of a box, the bottom of 
which is the apron board D. In place of the apron, a brass 
plate that forms the edge of the apron board overhangs the 
breast roll as far as the top of the roll, and is about ^ inch above 
the wire. The edge of the slice, which is sharp, comes exactly 
above the edge of the plate, forming a standard orifice } Wood or 
metal grids G help to eliminate eddies and ripples. The deckle 
straps come back against the ends of this slice box, and they arc 
held close to it by single-flange deckle-strap pulleys D, Fig. 32. 

iSce Part 4 of Section 1, Vol II. 


A small piece of rubber cloth, extending about 6 inches from the 
slice, makes a square corner, and it keeps the stock from leaking 
under the deckle strap before the strap is fiat on the wire. The 
slice plate is adjustable, to provide for two widths of the deckle; 
and the depth of the stock, which is the head in the shce box or 
pond, can be so adjusted as to control the velocity of emergence, 
and to make it accord with the speed of the wire. 


61. Soft Lumps. — It is well to note here some of the causes 
that make the paper break, causes due to conditions described 
up to this point. There are often lumps in the stock as it flows to 
the machine, and these may be either hard or soft. The soft 
lump is a new, thick blotch of stock, which has gradually accumu- 
lated either in the screen troughs to the flow box or in the flow 
box itself. These lumps occur when there are not a sufficient 
number of water jets in use to keep the stock from settling, and 
where fibers catch on splinters, screw heads, etc. After a lump 
becomes too heavy, it begins to flake in pieces, and passes from 
its lodging place into the hquid. It is then too thick to disinteg- 
rate again before it reaches the wire ; and the result is that when 
it passes under the dandy roll or between the couch rolls, the 
extra thickness causes a crushed spot that breaks away from the 
rest of the sheet, often breaking the sheet at this point, or else 
causing it to break as it passes through the machine. Soft 
lumps can be prevented by removing splinters, etc., and by 
using the water hose occasionally, thus washing the stock clean 
from its resting place, when the resting places are known. 

62. Hard Lumps. — Hard lumps are dark in color; they break 
away from accumulations of stock that have been gathering for 
days — sometimes for weeks. These accumulations are found, 
as a rule, between the screen plates and the screen diaphragms ; 
and they may be in the lower corners of the stock trough, the 
flow box, or even in the apron. The remedy is to clean these 
parts often enough to prevent such accumulations; this should 
be done at least once every week. 

63. Slime Spots. — Slime spots will often cause breaks; these 
spots come from the inside of the screens, from the pumps, and 
from the pipes on the entering side. Shme spots slip through 


the screen plates, when the plates are old and in poor condition, 
because the slots are then so large that the slime passes readily. 

64. Thin and Heavy Streaks. — The paper breaks where there 
are thin places parallel to the edge of the sheet. These thin 
places are due, sometimes, to the slice not being evenly adjusted 
or to the apron cloth not lying flat, which allows the stock to rush 
onto the apron and under the slices in eddying currents; this 
causes flow on the wire in several directions, and leaves heavy 
and thin streaks in the finished sheet of paper. However, the 
principal cause of these thin and thick streaks is a poorly designed 
flow box that allows eddies and cross currents in the stock as it 
flows to the wire. The only cure for this is so to re-design the 
flow box that the rush of stock onto the wire may be controlled. 
A perforated board, or grid, put in the last section of a flow box 
divided into compartments by baffles that are level with the top 
of the apron, will break up these large eddies and currents into 
man}'- smaller ones, and the stock can then go onto the wire in a 
quiet, uniform flow. A row of pins or fingers on the apron board 
may also be used for this purpose, but it is best to avoid 
obstructions. A new, nozzle type of orifice has an adjustable 
flexible lip that works well. 

65. Compartments in Flow Box. — Flow boxes in slow'-speed 
machines frequently have but one compartment, as in Fig. 29. 
With medium-speed machines, two-compartment flow boxes can 
frequently be used. In the case of high-speed machines, three- 
and four-compartment flow boxes are needed, see Fig. 30, because 
the necessarily rapid flow of the liquid is harder to control. 


66. The Deckle Frame. — Fig, 32 shows a deckle frame and the 
deckle parts. The side elevation (6) shows how the deckle 
frames F are supported on the shake rails T by the tubes L; it 
also shows the adjusting screws S, which serve to fasten and level 
the frame. By turning the handle H, both cross rods A are 
turned simultaneously by means of the four equal bevel gears 
(miter gears) B. Each of these cross rods is provided with a long 
screw thread on one end, the screws traveling in nuts that 
are fixed to the sleeves Y . Spur_ shafts M connect the bevel 
gears and keep the deckle frames parallel. When the slice 




clamps are loosened, the turning of the handle moves the 
frames in or out, according to the direction of turning. Each 

deckle frame can be moved independently, which enables the 
machine tender to steer clear of a bad spot on the wire, by moving 


the sheet to one side ; or he can give more or less trim on one side 
or the other, without changing the shtters, etc. The frames 
carrj'^ sleeves Y, which slide on the tubes X, made in sections, the 
outer section being supported at the shake rails. 

67. Each deckle frame supports a deckle wash trough C. The 
deckle strap K travels over the supports P, and is cleaned by the 
scrapers E on the top and sides, as it passes, and by streams of 
water playing over it; the water is led awayby a pipe connected to 
the outlet 0. The deckle pulleys D, next the breast roll, are sup- 
ported by brackets that are fastened to the outside of the frames, 
and the apron side pieces are clamped to the frame at this end. 
The details just mentioned vary in different makes of machines; 
but, in general, they all follow the type of design here described. 

Since the wire drags the deckle straps with it, the passage of the 
straps through the wash troughs and over the deckle pulleys 
should offer as little resistance as is possible. The scrapers E 
should be only close enough to clean the strap without holding it, 
and the supports P should have a smooth and easy curved surface. 
A strong stream of water should play on the strap wherever a scraper 
acts on it. If the strap be not clean, it may cause a ragged edge 
on the sheet, which may make it stick to a press roll and break the 

68. Shakeless Deckle. — If the deckle is supported on the 
Fourdrinier table bars (shake rails), it must shake with the for- 
ward end of the machine ; and when the machine is large, the deckle 
parts are heavy and cause considerable vibration. For this 
reason, shakeless deckles have been invented, the deckle part 
being supported by columns from the machine foundation. How- 
ever, the shakeless deckle cannot get away from the deckle strap, 
which must rest on the wire, and the wire causes the straps to 
shake and move to and fro while traveling from the table onto a 
pulley, and when passing from a pulley to the table. This shak- 
ing to and fro of the deckle straps on the wire near the deckle 
pulleys at the apron, will give a very uneven edge to the paper. 
In the case of a shakeless deckle, this effect can be overcome by 
clamping a strip of metal to the table bar, or to the deckle frame, 
in such a manner that it will hold the inside edge of the deckle 
strap down on the wire. 

69. Deckle Pulleys. — The deckle pulley should be amply 
large; not only because less work is then required from the wire 



but also because the straps will last longer. The following table, 
issued by a prominent manufacturer, gives the minimum diam- 
eters of deckle pulleys for different sizes of straps, and the pulley 
diameters should not be less than those here specified : 

Thickness of strap (inches) iHflfll 2 2i2| 
Diameter of pulley (inches) 16 18 20 22 24 26 28 

The second pulley is usually without crown, is 6 or 8 inches wide, 
of the same diameter as the flanged pulley, and is attached to a 
shaft extending across the machine near the first suction box. 
The shaft is carried in brackets that are supported by the table 
bars. Instead of a single long shaft, very wide machines have two 
short shafts. The pulle3^s are attached to the shaft by means 
of set screws or clamps; if these turn on the shafts, collars are 
used to keep the pulleys in position. An additional deckle strap 
support may be provided between the puUeys just mentioned and 
the wash trough. 

70. The deckle-strap pulley should never be allowed to stand 
still while the machine is running; the deckle strap should run as 
freelj^ as possible, because the wire must pull the strap. If the 
pulleys are not turning, the strap is forced to slip around them; 
the friction between the strap and the pulley then causes the 
strap to drag, and this, in turn, acts as a hold-back to the wire 
itself. Such a condition of affairs causes the wire to be strained 
on the edges, and cracks quickly begin to show themselves. The 
dragging of the strap on the wire also prevents the formation of a 
clean, even edge on the sheet of paper. It is not unusual to see 
paper machines with deckle pulleys of small diameter that are not 
even turning; the wires on such machines wear out much faster 
than thej^ would under better operating conditions. 


71. Purpose of the Slice. — Fig. 33 shows a shce in plan and 
elevation; there may be either one or two slices to a machine. 
As the stock in the flow box flows to the wire between the deckles, 
the thickness of the stream is controlled by a cross piece, called 
the slice, which is placed between the deckle frames, near the 
breast roll. The nearer the slice is to the breast roll the better; 
because the apron must be extended up to the slices, to insure con- 
trol of the stock, and the greater the area of wire that is covered by 




the apron the less is the forming surface that is available on the 
table. The stock that is held back bj^ the sHce is called the pond. 

72. Slice Details. — There are usually two slices, on fine-paper 
machines, about 12 inches apart, which extend right across the 
machine. The shce or sHces, as the case may be, are raised or 
lowered, so as to control the thickness of the stream of stock and 
keep the surface even. The height of the slices with respect to 
the wire is adjusted by means of screws A^; and when the proper 
height is obtained, the lock nutsL keep the slices stationary. The 


^ rB 

Fig. .33. 

brackets B, supported and moved by the screws N, have tee(T) 
slots, in which tee sUde bars move up and down; these tee slots 
are riveted to the deckle frames A. The sHces are made in two 
parts, Si and S2, to allow of side wise adjustment; and they are 
joined and kept in Hne with, each other by means of the adjusting 
screws K and the pinch screws G. These screws are held in 
clamps C, carried at the free end of either shce bar. When the 
deckle frames are moved in or out, as described in Art. 66, the 
pinch screws are loosened, so the shces will move with the deckle 
frames. The pinch screws sometimes pass through horizontal 
slots in the shces. 

73. Position and Adjustment of Slices. — Care should be taken 
that the lower edge of the sHce is kept straight and unbruised; a 
rough edge will gather fibers, which will break away in bunches 


and give trouble. The lower edge must be parallel to the surface 
of the wire, to insure a uniform thickness of stock as it flows onto 
the wire. Good results are obtained by placing the slices a little 
back of the center of, or between, the table rolls ; thej^ should never 
come exactly over the center, since a roll not in dynamic balance will 
cause streaks. The depth of the stock behind the slice controls 
the rate of flow of stock to the wire ; this depth may be as much 
as 3 feet, with the slice shown in Fig. 30. 

When the stock is slow and carries (retains) water well, the slice 
should be kept well down, especially when making fine papers. 
No more water should be used than is absolutely necessary to 
carry the fiber until it has been felted properh^ — the more water 
the more pumping. The level of the stock behind the shce should 
be such that the flow of stock will not be slower than the speed of 
the wire, when it flows onto the wire. The deeper the pond the 
faster, of course, will be the flow of stock onto the wire. 


74. Purpose of the Shake. — The breast-roll end of the wet part 
is swaj-ed to and fro continuously, which is called the shake; 
this agitates the pond behind the slices, and it also agitates the 
stock as it flows to the wire, which causes the fibers to felt 
together, as they settle with and through the water. The uniform 
interweaving thus obtained helps to make the paper equally 
strong in all directions. 

75. Amount of Shake. — The vibrating motion of the breast-roll 
end of the Fourdrinier wire is variable, the maximum movement 
being about f inch and the usual amount about | inch. This 
movement is caused by the shake head and shake connecting rod. 
The wet end of the Fourdrinier is supported on flexible springs 
on rocker arms, or is hung from an overhead beam, so the breast 
roll and wet end of the wire can swing to and fro. The shake head 
on K, Fig. 2, is a revolving disk, with an eccentric pin, to which one 
end of the shake connecting rod is clamped; the other end of the 
rod, connected to the breast roll supports, transmits a wire- 
vibrating movement. The amount of shake can be altered by 
moving the eccentric pin nearer to or farther away from the center 
of the shake-head disk, to suit the character of the stock; and the 
number of revolutions per minute of the shake head can be altered 
by shifting the belt on cone pulley K, to which the shake head is 


connected. Many of the new machines for such papers as news- 
print and the hke, are made without any shake ; this permits more 
substantial construction, and is one less cause for worry to the 
machine tender. 

The interweaving of fibers by the shake is partly due to care- 
fully adjusting the speed of the stock to the speed of the wire. 
The most carefully felted sheets are secured when the fibers 
settle by gravity as the water drains away; the fibers then fall 
naturally and evenly in all directions, and there is no "dragging 
the feet from under them," as it were. The effect of the shake 
is to knock the fibers down crosswise, while the forward travel 
of the wire pulls them down lengthwise of the sheet. The 
shake can be varied from a long, slow motion to a short, jerky 
motion; as a rule, the more violent the shake the better the 


76. Kind of Rolls. — Before describing the Fourdrinier rolls, 
attention is called to what a roll is and to its uses. There are 
many rolls across a paper machine, and they are made of various 
materials, as wood, bronze, steel, cast iron, and even stone. 
They all tend to sag in the middle because of their weight, even 
without carrying any load on them. In addition to their own 
weight, the table rolls support a part of the weight of the wire 
and a part of the weight of the stock from deckle to deckle. 
Press-felt rolls are subjected to the pull of the felts; sometimes 
there is half a lap of felt on a roll and a double pull, while some- 
times there is very little lap and a consequently small pull; 
sometimes the direction of the pull is upwards and sometimes it 
is downwards. The dryer-felt rolls have felts pulling upwards 
or downwards on them. The lower-press rolls have upper-press 
rolls on top of them, and these upper-press rolls have levers and 
weights on their journals, which increase the pressure of the 
upper-press roll upon the lower roll. In order that the machine 
may make a uniform sheet of paper, it is advisable that the top 
of a bottom roll be always straight as it turns over; similarly, 
the upper rolls should be straight across the bottom rolls. 

77. Crown of Rolls. — In order to keep the sheet of paper 
uniform, it is necessary to crown a single roll, or the lower roll of 
a pair, by making its diameter in the middle just enough larger 


than at the ends to make up for the sag in the middle that is 
caused by the weight the roll carries when in the machine; the 
crown is measured in thousandths of an inch. 

78. The Breast Roll.— The breast roll 4, Fig. 27, should not be 
crowned; because the wire wraps around a large part of its 
circumference, and if the roll were crowned, the wire will be 
stretched in the middle more than at the ends, thus making the 
center of the wire travel ahead; this would not only shorten the 
life of the wire but it would also tend to give an uneven surface 
on the table. 

79. Breast Roll Details. — The fact that the breast roll is 
driven by the wire makes it necessary, in order to lengthen the 
life of the expensive wires, that this roll should turn easily. It 
should be as light as possible; it should also be fairly large in 
diameter, so the wire may turn it more easily, and thus reduce the 
strain on the wire that is due to bending the wire around the roll. 
For a roll to revolve easily, it should be m balance; it should be as 
light as possible, yet stiff enough to keep its shape; lastly, the 
journals should be well lubricated. In more modern machines 
of a large size, the advisability of using ball or roller bearings 
on some rolls of the paper machine, to reduce the strain on the 
clothing,^ has become more generally recognized. 

Attempts to drive the breast roll independently have not 
been successful, because of the practical difficulty encount- 
ered in so driving the roll that its peripheral speed will 
exactly equal the speed of the wire, which is driven by the lower 
couch roll. 

Fig. 27 shows the breast roll in place, with the doctor as 
usually hung; the doctor scrapes off the pulp and keeps it from 
passing around with the roll, under the wire, and so stretching 
the wire and making bulges in it. For reasons previously 
stated, all breast rolls are ground straight, i.e., without any 

This roll is on the wet part of the machine, and should 
therefore be made of non-corrosive metal; it is also in position 
to pick up much fiber, and should therefore have a doctor to 
keep it clean. A similar line of reasoning may be applied to the 
other rolls of the machine. 

1 Clothing is the name given to the combination of wire, jacket, wet 
felts and dryer felts. 




Fig. 34 shows a section of a breast roll ; and it will be seen that 
every effort has been made to produce a breast roll that will be 
as light as possible. The extension with the brass sleeve is 

Fig. 34. 

provided for the purpose of slipping the end of a porter bar or 
lifting lever (see Fig. 35) over the end of the journal, as the 
breast roll is being lifted out of the machine when changing wires. 

To fit couch journal or breast roll journal 
Hard wood filler 

k'^^A^i.-::.-.- ^■;»t»^i^^^^N^»»^:^y!^t»»^»;^^^^y A;J^.»^■tJ^^^ 



■s- vy^^-y.-':^':;;^::;^ 

XX Heavy pipe 

Fig. 35. 

Eye for chain hoist 

80. Table Rolls. — Fig. 36 shows a roll that consists of a steel 
tube, cast-iron heads, and steel journals; this type of roll, covered 
with a brass tube or casing, is a standard design of Fourdrinier 

Fig. 36. 

roll. The illustration shows the general construction of stretch, 
guide, and wire rolls. 

The table rolls must be as light as possible, consistent with the 
securing of the necessary stiffness. They are made from a brass 
tube T, and have a cast-iron or brass head //, which carries the 
steel journal J. The journals rest in adjustable bearings that are 
supported by the shake rails, either on the rails or under them. 


81. Size of Table Rolls. — Fourdrinier rolls will soon deteriorate 
if acid stock (which arises from alum or antichlor) is used. The 
acid soon attacks the zinc in the brass covering; and, in course 
of time, it leaves only a rotten, porous, copper shell, which will 
readily break. This action occurs in connection with all brass 
parts. The table rolls have the smallest diameter of any of the 
Fourdrinier rolls, varying from 2 inches in diameter on small mach- 
ines to 6 inches or larger on the very wide machines. Machine 
designers now recognize the advantage of large rolls. 

82. Care of Table RollSv— Care should be taken to keep the 
table rolls turning; if a roll be allowed to stop turning (become 
dead), it wears the wire, and the roll itself wears flat where the 
wire passes over it. When a roll having a flat spot on it turns, 
it bumps the wire and makes ridges in the paper. If a roll will 
not keep turning after proper lubrication and adjustment, it 
should either be replaced with a new roll or, if only slightly worn, 
the journals and bearings should be inspected and corrected. 

In addition to reducing the friction between the table roll and 
the wire, there is another reason why the table rolls must turn; 
the moving surface brings the water out of the paper more easily, 
which does not occur w'hen the rolls are not turning. 

83. Effects Produced by Table Rolls.— Because of the wearing 
effect produced by the friction between the rolls and the wire, 
some machines have been equipped with a light belt drive on 

Fig. 37. 

these rolls; this eliminates dead rolls. Dead rolls may also be 
avoided by using ball bearings. In order that the rolls may turn, 
it is necessar}', of course, that the rolls be in contact with the wire. 
The diagram. Fig. 37, illustrates how the swiftly turning rolls 
on high-speed machines tend to throw water back under the wire. 
The rolls have much the same effect in inducing water to leave the 
under side of the wire as is produced by touching the inside of a 
wet tent or a string of rain drops. An English writer^ explains 
the action of the table rolls by assuming that a slight vacuum 
^ Chalmers, in Paper Making and Its Mnchinenj, 1920, p. 78. 


tends to form in front of the roll. A film of water may follow 
the roll to the wh'e and flow down the back side of the roll. 

A discussion of the dynamics of rolls is given in Art. 214. 

84. Efifects of Water and Its Removal. — It is necessary to have 
sufficient water in the stock to keep the fibers in suspension for a 
considerable distance on the wire; this affords time for the fibers 
to interweave properly and to produce a well-formed sheet. 
Since water drains rapidly from a free stock, such as is used for 
coarse papers, more water is used to produce this degree of 
suspension. High-grade papers are inade from slow stock, and 
the amount of water required is less in this case. Most of this 
water is removed as the paper passes the table rolls, and it is 
here that the paper is formed. 

The forming table and the suction boxes must take out enough 
water to keep the paper from being crushed at the couch press, 
which is the effect produced when the water is pushed out 
unevenly, leaving the fiber in blotches. With stock of the same 
freeness, the more table rolls the faster the machine can be run. 
If the paper be too wet at the first suction box, the machine 
should be slowed down, less white water should be added at the 
regulating box, or the stock should be made more free. To make 
the stock more free, warm the stock as it comes to the machine, 
or, better, change the treatment in the beater; heating costs 
money. If the forming table takes out the water too quickly, 
the instructions just given may be reversed, or several of the 
roll bearings may be lowered until these rolls are out of action, 
out of contact with the wire. Adjacent rolls should not be 
lowered nor those toward the suction boxes. 

When making tissue papers, the table rolls should be close 
enough together to keep the water that has been removed from 
being thrown back against the under side of the paper; a thin 
paper, such as cigarette paper, will be spoiled if drops are thrown 
against the under side of the wire. When starting a fast machine 
on coarse paper, it is well to begin with plenty of water, cutting 
it down if necessary; the opposite procedure should be followed 
in the case of a slow machine on fine papers. 


85. Purpose and Description. — The suction boxes must take 
out sufficient water to keep the paper from being crushed under 




the couch press. The usual design of a suction box 
is shown in Fig. 38. The box is made of bronze, and 
its interior is rectangular in shape. The bottom of 
the box is connected to the suction pump by means 
of a pipe 3; in some designs there are as many as 
six outlets from the box to this pipe. The rubber 
pistons 1 are pushed in or are pulled out by means 
of the handles 2, the ends of which fit into slots 
in the pistons and lock them in position. The 
pistons are set just under the edge of the paper, to 
keep air from entering the box. On the top of the 
box rests a perforated cover 4, made of hardwood — 
maple or mahogany — or, sometimes, of hard rub- 
ber or brass; maple is preferable for suction boxes, 
since it can be easily planed and kept smooth; 
and the cover must be kept smooth, to reduce the 
friction as the wire passes over it. The wire wears 
ridges or grooves in the covers, which soon destroy 
the m£sh or cause the wire to wrinkle and produce 
defects in the paper; the covers should, therefore, 
be planed smooth every week end. If the stock 
be coarse and but little suction required, it is bad 
practice to close one box entirely; it is better to 
decrease the suction on all the boxes, by slightly 
closing the valves on the vacuum pump suction. 

From 4 to 9 boxes are used, according to the 
kind of paper, speed of the machine, and the 
amount of water left in the stock after passing the 
table rolls. Some machines are equipped with a 
device for giving a reciprocating motion to one end 
or both ends of the suction boxes (all connected 
together), so as to minimize the scoring of the box 
tops. A great deal of work has recently been done 
on the subject of suction boxes, and successful new 
designs will doubtless soon be in use. 

86. Amount of Vacuum. — A vacuum gauge should 
be placed on the suction-pump line from the suction 
boxes, so the machine tender can be guided in his 
control of the suction. From 7 to 10 inches of 
mercury (vacuum) is ample for the suction; and if 
the work of the boxes is not satisfactory when^over 7 








inches of vacuum is shown on the gauge, it is better to place an 
additional box under the wire than to strain the wire too much by 
increasing the vacuum to above 10 inches. It is not unusual to see 
14 inches of vacuum on suction boxes; but this is bad practice, as 
the wires are then soon worn out. The suction pulls the wires down 
onto the top of the boxes and tends to make the wire drag, like a 

brake. A vacuum of 7 
inches on a 100-inch ma- 
chine is equivalent to a load 
of about 1000 pounds for 
each box; this not only- 
increases the pull required 
to drag the wire off the 
boxes but it also causes a 
suck in and release as the 
wire passes, which strains 
the mesh. In a patented 
arrangement, this effect is 
minimized by placing the 
boxes contiguous. As pre- 
viousl}" stated, these strains 
on the wire should be made 
as small as possible, so as 
to save the wires and make 
good paper. 

87. Suction Pumps, — 
The suction pump is often 
similar in design to the stuff 
pump, but the valves must 
act quickl}'. Fig. 39 shows 
a section of one c^dinder 
of a suction pump, which 
may have two or three cylind(>rs. The suction-pipe connection 
S is connected to the pipe 3, Fig. 38, of the suction boxes. 
Between it and the pump is a separator for taking out the air that 
is drawn through the paper as the water is removed. This 
water contains recoverable fiber. The discharge pipe D delivers 
the water and fiber, sucked from the suction boxes, into save- 
alls or to the sewer. The action of the disk springs, as the 
plunger moves, is the same as that of the ball valves of the stuff 
pump shown in Fig. 5; the spring insures quick and positive 

Fici. 39. 


closing, with minimum leakage. In Fig. 39, the plunger P 

has just finished a down stroke; the air in the pump has been 

expelled through Z), and the lower valve is about to open, as the 

up stroke of P admits air through S. The cushioning effect of 

the air is so materially reduced by the vacuum created that the 

seating of a valve is much more sudden than it would be if it 

were moving in the atmosphere; this necessitates moving parts 

of special design. Rubber is generally used in the manufacture 

of the suction and discharge valves; but experience has shown 

that rubber-ball valves are not as good as rubber disks, with 

controlling springs. 

88. Displacement of Suction Pumps. — The displacement of the 

suction pump should approximate 500 cu. in. per inch of width 

of wire and for each 100 feet of paper made per minute. Hence, 

for a width of 130 in. and a speed of 450 ft. per min., the dis- 

placement under these conditions should be 500 X 130 X ^ru) 

= 292,500 cu. in. per min. However, this amount is possibly 
excessive, if applied to high-speed news-machine problems, when 
the speed is over 600 ft. per min. ; the paper then loses its moisture, 
and the work required of the pump is less in the last suction 
boxes than in the first boxes. While the paper machines may 
have a varying number of suction boxes for the same speed, the 
greater part of the work done by the pumps is in the first two or 
three boxes; therefore, the same displacement of pump will, as a 
rule, take care of an extra suction box, if the displacement be 
calculated according to the above rule. The character of the 
stock governs to a certain extent the amount of suction require d ; 
for instance, groundwood is slower stock than sulphite, and thus 
requires a higher vacuum to suck the water out. But when the 
stock is slow, the machine is usually slowed down. 

On a suction couch roll, a higher vacuum is necessary in order 
to do efficient work; this is also true of the wet-press suction boxes. 
The size of the pump for press suction boxes can be taken care of 
by allowing 275 cu. in. displacement of suction pump per minute 
per inch of width of press roll. In order to exert a continuous 
suction on the wire or press felt, the smallest capacity of pump 
that is practicable is 6" X 8", that is, 6 in. in diameter by 8 in. 

Other types of exhausters, especially centrifugal pumps, are 
also used on suction boxes instead of the displacement pumps 






here described; these other designs 
are at least equally efficient. A 
special treatment of the subject of 
pumps is included in Vol. V, in the 
Section on General Mill Equipment. 


89. The Guide Rolls.— The guide 
roll 8, Fig. 27, is provided with a 
wire guide on the front side of the 
machine. A design of wire guide, 
as attached to the guide roll on a 
left-hand machine, is illustrated in 
Fig. 40. The guide acts by shifting 
the position of the bearings, carry- 
ing the front end of the roll for- 
wards or backwards as the wire gets 
out of line. 

90. The Palms. — Referring to 
Fig. 40, two palms, or fenders, Pi 
and Pi, are fixed on a wooden rod 
A , which crosses the machine under 
the wire in such a manner that the 
edges of the wire just clear the 
palms. Now consider what hap- 
pens when the wire travels to the 
front side^ and pushes against palm 
Pi. This action moves the wooden 
rod A to the front of the machine, 
carrying with it link M, which is 
firmly keyed to rod A; and this, 
in turn, moves bell-crank levers 
N and 0. The latter revolves 

^The front side of the machine is the 
tending side, the side opposite the one on 
which the drive is located, which is called 
the back side. Hence, on a left-hand 
machine, the front side will be on the 
right, when looking toward the wet end 
(see Art. 54). 


around the center pin Q, which is carried by bracket B. One 
end of lever is connected to rod C, which, as the front palm 
comes forward, pulls the double pawl L and R, so that pawl R 
locks into the rachet wheel W. Since the double pawl is hung 
on the eccentric E, it moves up and down once with every revolu- 
tion of the guide roll, and it is constrained to move vertically. 
When, as in this case, the rod C pulls pawl R, which is in gear 
with the wheel, the pawl pushes down on the wheel, turns it 
around, and causes it to travel to the right on screw K, toward 
the direction in which the wire is travehng. Since the ratchet 
wheel carries the front bearing D of the guide roll, the result of 
the above described movements is to screw the front side of the 
guide roll forwards by means of its own revolutions, thus causing 
the wire to be forced by the guide roll to travel back again to 
its normal position. 

If the wire tend to travel toward the back, or driving, side of 
the machine, the movements above described are reversed; pawl 
L then locks into the ratchet wheel, lifts on the ratchet wheel, and 
causes it to travel to the left. The new position of the roll causes 
the wire to retrace its path toward the front of the machine. 

There are other types of wire guides, but they all work on the 
same general principle — that of shifting the front bearing of the 
guide roll. A widely used tj^pe has but one palm, held against 
the wire b}- a spring; it is especially adapted to wide machines. 
A new type has no palm; a water jet which strikes a spoon 
lever if the wire moves either way, actuating the gear. 


91. The Watermark. — When it is desired to make a water- 
mark (a name or design) on the paper, it is effected by using a 
dandy roll. A dandy roll is a skeleton roll, covered with wire 
cloth, upon which the design is worked in fine wire, though brass 
letters are sometimes used. This raised design makes the soft 
paper thinner where it comes in contact with the design, and the 
outline shows clearly when the paper is held between the eye and 
the light. 

92. Wove and Laid Papers. — If the paper is to be alike on 
both sides and without a watermark, the dandy roll is covered 
with fine wire, similar in texture to the machine wire. This 
dandy roU produces what is called wove paper; because the wire 
impressions are similar on both sides, and the paper has the appear- 




ance of being woven. A dandy roll that has a series of wires on its 

surface, the wires being so arranged as to produce parallel hnes 
on the paper, these lines being more transparent than the rest of 
the paper, produces what is called laid paper. 

93. Size and Position of Dandy Rolls. — The diameter of a 
dandy roll varies from 7 to 2-4 inches, depending on the width and 
speed of the machine, the design of the watermark, and the kind 
of stock; it is placed on the wire and between the suction boxes, 
see 7, Fig. 27. The roll rests on the wire, and its journals revolve 
in guides rather than in bearings. The roll is turned by the 
friction between it and the paper. As this roll runs on the surface 
of the paper, it presses out some water, and it gives the paper a 
closer and finer finish, which is its primary function. 

Fig. 41. 

The circumference of a dandy roll is usually a little less than 
the distance (lengthwise) desired between the watermarks on the 
dried sheet; this allows for stretch. The distance crosswise 
between the designs is a little greater than is desired in the dried 
sheet; this allows for shrinkage. Dandy rolls for loft-dried 
papers should have a greater width between designs, because of 
the greater shrinkage in high-grade papers. 

94. Fig. 41 shows a design of dand3-roll stand, and by referring 
to Fig. 27, the usual position of the dandy roll will be noted; it is 
generally placed after the first set of suction boxes, but not directly 
over a roll. Fig. 41 shows the adjusting screws S, with a thumb 
head, and wing nut W, for adjusting the height of the dandy-roll 
guides B to accord with the size of the dand}' roll D. Lever A is 
so linked to the dandj^-roll guides or bearings that an upward 
movement of the lever will immediately hft the dandy roll from 
the surface of the paper, if, for any reason, it is necessary to do 


so. When not in use, as when starting the machine, the dandy- 
roll may be hung in bracket H . 

When the dandy roll makes proper contact with the paper, a wet 
streak of even width shows just behind the roll. Experience is 
required to get the right amount of wetness to the paper, so the 
dandy roll will make the right impression. This is done by con- 
trolling the suction and by proper beating of the stock. The 
paper in this book is made with a wove dandy. A surface mark is 
obtained on some machines by printing the letters on the paper as 
it passes over one of the hard rolls of the press part. 

95. Defects Caused by Dandy Rolls. — Dandy marks some- 
times cause defective paper and breaks. The wire cloth that 
covers the skeleton drum may become plugged in the meshes with 
fine particles of stock and filler; and when this occurs, the water on 
top of the sheet cannot penetrate through the plugged meshes. 
As a consequence, the sheet at these points tends to stick to the 
face of the dandy roll, and it is slightly lifted by the roll. This 
action causes a mark on the sheet that has somewhat the shape 
of a half moon, and there is only one remedy for it: the dandy roll 
must be taken from the machine and thoroughlj' washed out with 
water and steam. When the meshes are badly plugged, and the 
plugs are dried into the wire cloth, it may be necessary to use a 
steam hose. In some cases, dilute oil of vitriol (sulphuric acid), 
lightly applied with a cloth, is necessary to clear the dandy roll 
of these obstructions, and some mills keep steam or air jets blow- 
ing through the dandy on the machine. A piece of wet felt, tacked 
to a bar, may be hung the length of the dandy for use as a wiper. 

Unless very carefully cleaned at the end of a run, some paper 
stock will adhere to the wire, and the acid treatment will be 
required when the dandy is next used. The acid wash is prepared 
by pouring sulphuric acid into a pail of water until a distinct acid 
taste is noticed, about like lemon juice. The roll is placed on two 
supports (little horses); it is then scrubbed carefully, and is 
washed thoroughly with a hose. Pour the acid into the water; 
it is dangerous to pour water into the acid. 

96. Putting On and Removing Dandy Rolls. — To put on a 
dandy, the machine tender holds it vertical; then, with the 
journal in one hand, he makes a fulcrum of the other hand, about 
2 feet from the lower end, rests his elbow on the shake rail, and 
gradually lowers the upper end. His back tender stands on the 




back shake rail, catches the back end, and fits the journal to its 
bearing. The machine tender gives the roll a slight twirl in the 
direction of the paper travel as he drops the roll quickly and gently 
on the sheet; this can be done without breaking the sheet. 

To remove the dand}^, the back tender and the machine tender 
stand as before, and they quickly lift the roll from the paper. The 
back tender gives his end a quick strong lift, but not too strong, 
and the machine tender brings the roll to an upright position, 
where he can balance it; he generally gets a good wetting from the 
water in the roll. Wide machines have a plank walk across the 
wire, supported from the frames, so the roll way be carried off. 


97. Purpose of Couch Rolls. — The function of the couch (pro- 
nounced cooch) rolls is to remove water from the formed paper 
and pack the fibers firmly together, so that the sheet is strong 
enough to pass to the first press. The top couch roll is couched 
toward the wet end; that is, it is not directly over the center of 

1 fVidth of Machine 






\ Diameter of Roll 






Fig. 42. 

the lower couch roll, see Fig. 27, but bears somewhat on the wire, 
which acts as a couch. This arrangement permits water to be 
pressed out, and it causes the paper to be gradually squeezed 
between the wire and the felt jacket on the upper roll before being 
finally squeezed between the two rolls. The couching action 
guards against crushing the paper, which occurs if the sheet be 
too full of water when entering the "nip" between the two rolls; 
and the water has a better chance to get away when squeezed 
through the wire. 

98. The Lower Couch Roll. — A section through a lower couch 
roll is shown in Fig. 42. The extension A provides room for the 


lifting pipe or porter bar, Fig. 35, to fit over; C is the journal, and 
5 is a shell, made of bronze, gun metal, or brass. This is a driving 
roll, with a heavy load to carry; it is exposed to moisture, and 
must not be crowned. A comparison of Figs. 42 and 34 shows 
that the couch roll is more solidly designed than the breast roll. 
As is the case with the breast roll, the lower couch roll is not 
crowned because an increase in the diameter at the middle of the 
roll would tend to stretch the wire or would, in any case, make it 
travel faster at the center, which would cause strains and partially 
close the mesh. In most cases, the lower couch roll is covered 
with a brass or gun-metal shell. 

99. Driving the Couch Rolls. — The lower couch roll is driven, 
and it pulls the wire over the other rolls and the suction boxes — a 
heav}' load. The tendency of the wire to slip on a smooth roll is 
sometimes counteracted by covering the roll with rubber. A 
grooved roll is sometimes used on light papers, and a felt-jacket 
covered roll may be necessar}^ to prevent the wire from marking the 
paper, the weight of the upper roll pinching the paper against the 
wire and the lower roll, thus impressing the mesh of the wire in 
the soft sheet. 

In spite of all attempts to devise a mechanical drive — by 
means of a slipping belt, etc. — the upper couch roll may be con- 
sidered as driven indirectly from the lower roll; the lower roll 
drives the wire, the wire carries the soft sheet of paper, and the 
paper really drives the upper couch roll. The nature of this 
sheet of paper demands that very careful attention be given to 
the condition of the bearings, to lubrication, and to the setting 
of the upper roll with reference to the lower roll, both as regards 
their position and the prcssm-e between the two rolls. 

100. Crushing — Cause and Remedy.— Adjustment of the 
pressure between the couch rolls requires consideration of the 
wetness of the sheet, to prevent crushing of the sheet. Crushing 
is a blotch\' or curdy appearance of paper; it is caused by a too 
rapid pressing out of water, which pushes the fillers into 

Crushing is common with heavy papers, the fiber of which may 
pile up before the roll, hke sand in front of a small wheel. The 
remedy is to increase the freeness of the stock, using less water 
(which may, however, interfere with good formation), putting 
more table rolls into commission, increasing the suction on the 




suction boxes, and relieving the pressure on the upper couch roll; 
it may also be overcome by using a suction couch roll. 

101. Couch-Roll Housings. — The two bearings of the upper roll 
are carried by the swinging arms of couch housings, see Fig. 43, 
which shows diagrammatically two typical designs. View (a) 
shows a bevel pinion on shaft S, which is actuated by a hand 
wheel (not shown); this pinion turns the larger gear A, which 
acts as a rotary nut and pushes or pulls on the screw B, thus 

Worm and Wheel Bell Crank IToutlng 

Fig. 43. 

moving the coucher arm L around the pivot pin P. Eig. 43 ih) 
shows a worm and worm wheel instead of a bevel and pinion. 
The worm W is actuated by a hand wheel (not shown) ; it turns 
the wheel G, which acts in the same manner as the larger bevel 
gear A, in view (a). 

The design shown in view (a) is suited to fairly narrow 
machines, while that shown in view (6) is for wider-faced and 
heavier upper couch rolls on wider machines, the worm-and- 
wheel gearing giving a larger lifting effect than the bevel gears. 
It would appear to be well worth while to consider the use of 
small motors for furnishing the motive power to lift couch rolls, 




move stretcher rolls, and to shift belts on the extremely wide 
paper machines now being built. 

Referring to Fig. 43, all upper arms are provided with weights 
and levers, attached to hook H, for controlling the pressure 
between the rolls across the machine. As will be explained 
later, in describing the press part, this design is similar in all 
practical details to that used for any press, whether for a couch 
roll or for any press part situated farther up the machine. 

Fig. 44. 

The upper couch roll is covered with a felt jacket, to secure a 
dry sponge effect on the wet paper; it is a descendant of the 
traveling upper felt E, Fig. 26. Further information concerning 
the use of the couch roll and the jacket will be found in Arts. 
117-122 and 141-146. 

102. The Guard Board. — The guard board is so placed that it 
squeezes out of the jacket much of the water that has been 
absorbed from the paper, and it scrapes off lumps of pulp that 
might go around and dent the wire. With the water is a certain 
amount of filler and fiber, which is washed out at the ends of the 
roll by the shower pipe, shown on the press side of the guard board 
in Fig. 27, and at F in Fig. 44. The guard board is set behind 
the center of the couch roll; this makes a little trough, which may 





be increased by a small roll 72 or by a felt wiper. Pipe F and 
roll R may be supported from the couch-roll housing. 

The guard board should be adjustable, and it should have a 
flexible edge that can be adjusted to give a uniform pressure 
over the width of the jacket. Fig. 44 shows a typical guard 
board. A plank E is supported by cast-iron brackets, which are 
bolted to the top of the bell-crank arm of the housing. On the 
front of this plank, the light guard-board blade D, made of 
maple, is held in place by a series of spring boxes //; through these 
boxes, double thumb sci'ews pass, wdiich are operated from above. 
If a part of the jacket is running wet, a turn of the upper thumb 
screw B, which operates on one of the springs, gives additional 
pressure to the blade; if the jacket is running dry, a turn of the 
lower thumb screw A serves in like manner to relieve the pressure 
of the blade. Saw cuts in the upper edge of the blade increase its 
plial:)ility. Since the guard board acts like a brake, a gentler 
pressure on it reduces the power required to drive the Fourdrinier, 
and it lengthens the life of the upper couch-roll jacket and of the 
wire. Perforating the shell of this upper couch roll facilitates 
removal of water from the jacket. 


103. Suction Couch Roll. — Manj^ machines are equipped with 
a suction couch roll, and some have a suction press roll also; the 
former supplants the conventional top and bottom couch rolls, 
and the latter supplants the bottom roll of a pair of press rolls. 
In principle, a partial vacuum is created in the roll, and atmos- 
pheric pressure, instead of roll pressure, packs the fibers and 
squeezes water from the paper. Many advantages are claimed 
for these suction rolls, and they have affected, to some degree, 
the design of the newer paper machines. 

104. Construction and Installation. — The construction of the 
suction couch roll, and the method of its installation, is shown in 
Fig. 45. Here (a) is a longitudinal section, (6) is a cross section 
on the line XX, (c) is a right end-view, and id) is a diagram 
showing wire and felt. A perforated bronze shell A is mounted 
in substantial bearings B; the diameter and thickness of the 
shell depend on the width, speed, and drag of the wire, and the 
best of machine-shop work is required. The shell is revolved 
at the speed that is proper to drive the wire. C is the stationary 


suction chamber; it is connected to a powerful rotary vacuum 
pump, which is driven from a constant-speed Hne shaft. The 
pump is connected at V, and is usually located in the basement. 
Contact between the suction chamber and the inside surface of 
the revolving shell is made with special packing, which is held in 
place b}' springs, or water, or compressed air. A piston arrange- 
ment D, operated by shaft and handle H, is provided on the roll, to 
adjust the length of the suction area to accommodate any width 
of sheet made on the machine. This piston fulfills the same 
purpose as the pistons 1 in Fig. 38. The chamber C need not be 
vertical, it may be swung back or forward. In view {d), the 
small roll R is a, light aluminum roll, which is sometimes used to 
help maintain the proper draw of the sheet between the suction 
couch roll and the first wet felt. 

105. Amount of Vacuum. — The degree of vacuum that can be 
maintained in the suction couch roll depends largel}'^ upon the 
weight and character of the paper made; about 15 inches of mer- 
cury is a fair average, being least on free stock and on thin paper. 
The shell A is driven by gear G from pinion T, shown in end 
view (c). It is to be noted that a suction couch roll requires 
more power for its operation than the ordinary pair of rolls. 
Since the shell is perforated, the ordinary strength formulas do 
not appl}^ when designing these rolls. 

106. Operation of Suction Rolls. — In order to understand the 
operation of the suction rolls, it must be borne in mind that after 
the web of paper has been formed on the Fourdrinier wire, the 
essential remaining problem, insofar as the paper machine itself 
is concerned, is largely one of removing the water that is in the 
sheet; and this is accomplished by the suction boxes, the pressure 
of the couch and press rolls, and by evaporation. There are 
different ways in which the necessary pressure may be applied 
at the wet end. With present-day, relatively high, operating 
speeds, the water must be eliminated very rapidl}- from the 
newly formed and tender sheet; yet, if this be done violently, 
the finish and strength of the paper suffer, to say nothing of the 
breaks that follow. 

107. How the Pressure Acts. — In the case of the conventional 
couch and press rolls, most of the pressure is exerted on the line 
of contact of the top and bottom rolls. This line of contact is, 


of necessity, very narrow; and since the resulting pressure is 
tremendous, per unit of contact area, the water is violently 
forced from the web of paper as it passes between the rolls. Some 
deranging of the fibers, or a partial breaking down of the fibrous 
structure that has been so carefully built up in the forming of the 
sheet, can scarcely be avoided with such pressing. 

With suction rolls, line pressure is replaced by atmospheric 
pressure, which is both constant and uniform, and is applied to 
a controllable unit of area on the moist paper. Instead of a 
great pressure on a narrow contact, there is, with the suction roll, 
a lighter and milder pressure, which is distributed over a greater 

108. Manner in Which Suction Roll Acts. — The suction couch 
roll eliminates entirely the necessity of the old top couch roll, 
with its felt jacket and guard board, both of which require 
considerable attention, and which are responsible directly for 
many of the troubles of the machine tender, such as crushing, 
pitch spots, wire marking, pick-ups, and accidents to wires. The 
avoidance of these troubles means greater production. 

The suction-couch roll does not displace the regular flat suction 
boxes on the wire; but the suction can usually be kept less, thus 
putting a smaller strain on the wire and giving it a longer life. 
Damp streaks are avoided, since the atmospheric pressure is 
uniform; the wires glide easily and run longer; and clearer water- 
marks are possible, when no top-couch roll is used. 

Suction rolls are in operation in machines running at speeds 
up to and above 1000 ft. per min., and the variation in the weight 
of papers being made is from 8 to 300 pounds. 

109. Manner in Which Paper Should Be Taken off the Wire.— 

When starting the machine and taking the paper off the wire, 
it is very important that the sheet be picked off the wire below 
the suction area. The paper will leave the wire more freely 
when using the suction couch roll than with the old couch rolls, 
provided it be taken off low enough to avoid the effect of suction. 
The wire must not be struck hard when picking up the ribbon 
(Art. 52). In several cases, wires have been ruined in this way, 
or when trying to pick the sheet off the suction area. 

On light-weight sheets and on machines operating at high 
speeds, it is convenient to make use of a patented compressed-air 
nozzle, to blow the ribbon from the wire onto the first felt. If 


unusual difficulty be experienced with the draw, it can usually 
be traced to the felt suction box; for which reason, this box should 
be equipped with a vacuum regulator that can be weighted to 
change the degree of vacuum carried. As the vacuum increases, 
the paper will run down where it leaves the wire; and as the 
vacuum decreases, the draw tightens; because the felt runs slower 
or faster, respectively. In some installations, the regulation of 
the felt suction box is so close that the additional removal of an 
ordinary f-inch washer, used as a weight on the vacuum regulator 
valve, will change the draw of the paper perceptibly. If no 
draw roll, as R in Fig. 45(d), is used, and the sheet is drawn too 
tight between the wire and the felt, the sheet will be spotted; 
and if it be allowed to run too slow, it Avill give trouble on 
the felt. 

The pistons D, Fig. 45, should be carefully adjusted to the 
width of the wet sheet. If the pistons are not out far enough, 
the edges of the sheet will run wet, and the sheet is apt to wrinkle 
on the felt. Sometimes the edges will give a little trouble, if the 
deckle straps are worn and leakj^; in such cases, either re-grind 
the deckle strap or make use of a squirt on either side of the 
sheet, to cut away the fringed edges. If the pistons are put too 
far out, there will, of course, be an unnecessary reduction in the 
vacuum, because of the extra air being admitted. 

110. Efifect of, and Prevention of, Lumps. — When the suction 
couch roll is used without a suction roll on the first press, lumps 
(if they occur on the sheet) may cause a breakdown at the first 
press roll. The proper remedy is to get rid of the lumps, which 
are usually caused by dirty screens that are in need of repair. 
If the cause of the lumps cannot be determined, a rubber dandy 
roll may be run on top of the sheet, over the suction couch roll. 
This is a soft rubber-covered roll, of small diameter, and only 
heavy enough to squeeze the surplus water out of such lumps; it 
also has the tendency to close up the sheet and produce a higher 
vacuum. Some kinds of paper will not stand for its use, however; 
and it is not recommended, except in special cases. 

If the machine is not already so equipped, the addition of a 
flat suction box on the first felt will help to lay the paper flat on 
the first felt, and it will help to regulate the draw, as previously 



111. Varying the Tension of the Wire.— Fig. 27 shows a 
stretch roll 12 on the inside of the wire, which is provided with 
a hand-operated screw, so the stretch roll can be moved up or 
down, in a vertical direction, according to whether the wire 
tension is to be decreased or increased. It is not necessary that 
a Fourdrinier wire be very tight ; the pull of the couch roll on the 
wire, which drives all the table rolls and the breast roll, will 
keep the forming-table part of the wire tight, even if the return 
of the wire be loose. When using the stretch roll, the machine 
tender can actually pull a wire apart, if he is not careful, and 
he may easilj' put an undue strain on it. It is best to order the 
wire long enough to permit the stretch roll to rest in a loop. 

112. Stretching of the Wire.^ — If the wire runs nearly straight 
across the stretch roll from the neighboring rolls, it is much more 
likely to be overstretched, without realizing it, than when the 
stretch roll hes in more of a loop. The tension of the wire due 
to the stretch roll only should not exceed 3 pounds per inch of 
face of the wire, and this tension should not be increased or 
decreased as the wire grows older. If, because of wear and tear 
due to being in service, the tension of a wire be altered, the joints 
of the mesh will loosen and begin to work ; and the wire will then 
shear itself into cracks much more quickly than if the original 
tension had been maintained. The wire of the Fourdrinier 
will naturally get a little longer as it gets older, largely because 
of the pull and the friction of the suction boxes. The increase 
in length of a wire may be taken care of by a proper use of the 
stretch roll, without increasing the tension of the wire. The 
stretch roll should be used very carefully, in order not to put 
excessive tension on the wire. 


113. Elevating Device. — Fig. 27 shows an elevating device 
that is often used on high-speed news machines; different makers 
use different devices. The object sought is to give the wire such 
a pitch that the stock emerging from the slice or flow box will 
travel down grade, and at about the same speed as the wire is 
traveling; this results in far better formation and more uniform 
quality. It will be seen that the beams K, hung on either side 


of the machine, carry the table bars 13, table rolls 5, and breast 
roll 4, and also the deckle parts. The save-all boxes are also 
supported on the beams K. The hand wheel W shown at the 
flow box is on a shaft that carries two worms, which actuate a 
big worm wheel on either side of the machine. These worm 
wheels are keyed to vertical shafts, which have screws cut on the 
bottom ends, the screw threads being above the end bearings in 
which these vertical shafts turn. These screws turn in nuts, 
which are a part of the flow-box ends of the supporting beams K. 
As the vertical shafts are turned bj' the operator at the hand 
wheel, the nuts on the ends of the beams K travel up or down, 
lifting or lowering the flow box, the breast roll, and the wet end 
of the Fourdrinier. 

In wide machines, the elevating devices, which are similar to 
that just described, are operated by a small motor instead of by 
a hand wheel. The majority of paper machines are so designed 
that the breast roll can be raised or lowered 2 or 3 inches above 
or below the level of the couch roll. High-speed news machines 
are now often built with a permanent pitch of 18 inches or more 
to the wire. 



114. Removing the Old Wire. — One of the most important 
tasks of the machine crew is that of putting on a new wire. 
When changing wires, first see that there is no danger of any roll 
falling out of its bearings; then make two short cuts in the old 
wire, about an inch apart and close to the couch roll; put in the 
clutch, and run the cut part onto the lower couch roll, past the 
nip; after which, stop the wire. Take the inch-wide strip that 
has been started by the two cuts, and tear it off right across 
the machine; put in the clutch, and roll the wire onto a wood 
core until the roll is large enough to lie between the lower couch 
roll and the first press-felt roll; then start up the wet felt, and 
roll the old wire up between the first press-felt roll and the 
coucher (couch roll). The roll is started with the core lying on the 
top of the wire. The old wire should be preserved ; it is valuable. 

The machine tender then takes off the slices and folds back 
the apron; when possible, lift the deckle frames and sHces com- 




pletely off the machine. The crew should now take out the 
suction boxes and table rolls, laying them on the tending floor, 
in such order, that each part will be returned to the same place 
or to its own bearings, when the new wire is put in. All these 
parts should be well cleaned and scrubbed, to remove any clay or 

Next remove the save-all boxes and the wire-carrying rolls; 
the latter are usually lifted out, they may be slid out on planks, 
in the case of wide machines and heavy rolls. Lastly, remove the 

Fig. 46. 

breast roll, by means of the rails and light trucks, upon which the 
roll is lifted with the chain hoist. Now send for the new wire, and 
have the millwright plane the suction-box covers. The upper 
couch roll is lifted by means of the bell cranks and gear, and the 
cap of the lower roll bearing is removed. 

The porter bar is placed in the wire by putting it on the end of 
the wood spar A, Fig. 46(a), which is in the wire when purchased 
and received. As this spar is pushed out, carefully follow it 
with the porter bar. When the spar has thus been replaced with 
the porter bar, one end of the bar, Fig. 35, is placed securely over 
the extension of the lower couch journal, and the other end is 
lifted by a chain fall (block and tackle) and held in position, so 
that the end of the couch roll is carried at the right height to allow 


the new wire to be slipped over it. The lower bearing is removed, 
and all parts that might touch the wire are wiped clean. The 
new wire is then carefully slid over the lower couch roll, great 
care being taken not to kink it. Kinks form very quickly and 
easily, and they practically ruin a wire. 

115. Putting on the New Wire. — The roll of new wire is now 
placed on top of the lower couch roll, Fig. 46(6), spar A is 
replaced in the wire roll, and the wire is unrolled, as indicated 
by the arrows; the wire is, of course, far longer than is indicated in 
the figure. Spar A , together with the wire on it, is carried toward 
the flow box sufficiently far to permit the breast roll to be placed 
inside of the wire, a few table rolls being replaced to prevent much 
sagging; the breast roll is slid on a plank (or rails), laid inside the 
wire, until it can be placed in its bearings, after which, the plank 
is removed, care being taken not to injure the wire. Only the 
rolls under the wire (except the upper couch roll) may be left in 
the machine. The new wire should be carefully examined for 
defects; if any are found, roll up the wire carefully and put it 
back in its box for return to the manufacturers; but don't 
blame the wire man for the result of carelessness in the mill. 

Next put the supports and save-alls in their proper places, and 
then the table rolls, one by one; the suction boxes follow, then the 
carrying rolls, the guide roll, and, lastly, the stretcher roll. The 
greatest of care should be taken to see that there are no loose parts 
or rolls that can possibly fall on the new wire; that top brasses, 
pins, screws, bolts, etc. are all in place; that the shower pipes are 
up, the doctors replaced, and that the guide mechanism is in 
place. The palm or palms on the guide bar must clear the edge 
of the wire by about /g inch. See that all pipe connections are 

The end of the save-alls should not be close enough to the 
breast roll to allow any stock to become lodged between them. 
Since the back of the breast roll passes down from the save-alls 
to the breast-roll doctor, it retains stock; therefore, a strong shower 
pipe should play on it just above the doctor, to wash accumula- 
tions off this doctor and through the wire or to one side, by a 
trough. The doctor should have a felt or a rubber edge, to keep 
the breast-roll surface clean and to keep any stock from travehng 
up between the wire and the breast roll, which would cause ridges 
in the wire. The pressure of the doctor against the breast roll 
should be as light as possible and still permit it to clean the roll. 


Any extra pressure will act like a brake, which will increase the 
work that the wire must do in turning the roll. The pulp thus 
scraped off by the doctor may be made to fall into the save-all 

116. Care of the Wire. — Proper care of the Fourdrinier part of 
the machine, either when idle or when being prepared for service, 
is extremely important; both for the sake of the machine itself 
and for the resulting saving in the expensive wire. Under care- 
less management, the wire may last only a few days, when several 
weeks of service may be obtained from it, if properly attended to. 
Generally speaking, the life of the wire largely depends on the 
machine tender. 

When putting on a wire, the little patches of hard pulp that 
stick to the rolls are sure to cause trouble, unless they are 
thoroughly removed. Again, when putting the wire on, kinks 
are very liable to be forced in it, and the bends so produced 
always develop into cracks. It is necessary that the seam on the 
wire be kept straight, and this cannot be effected unless the 
guide roll and stretch roll are square with the machine, and both 
are level. 

117. Testing Squareness of Table Rolls. — The proper way to 
test the squareness of the table rolls across the machine is to 
measure with a tape line or a pair of trams (two sharp pointers, 
at right angles to and adjustable along, a long stick or bar), to 
ascertain whether the distance between the ends of the several 
rolls is the same on either side of the machine. Care should be 
taken to select the points at easy places where the measurement 
begins, and center-punch marks should be made to locate these 
measuring points. The punch marks should be made directly 
over the center of the journals of, say, the first press roll or the 
couch roll. 

When satisfied that the measurements are the same on both 
sides of the machine, measure diagonally to see if the rolls are 
square with the machine; for instance, see if the measurements 
between the centers of the journals of the couch rolls and the 
breast roll are equal on either side. It is also quite as important 
to see that the measurement from the center of the front journal 
of the couch roll to the center of the back journal of the breast 
roll is the same as from the center of the back journal of couch roll 
to the center of the front journal of the breast roll. 


These distances may be too great to be measured easily; but 
they can be checked by measuring diagonally from the couch-roll 
journals to the first table-roll journals, or to the suction boxes, 
making continual diagonal measurements until the breast roll 
is reached. The measuring should be done with a steel tape. 

118. Leveling and Lining-Up the Table Rolls. — When the rolls 
have been squared, carefully level them across the machine. 
Line up the rolls by placing a tight wire from the top of the breast 
roll, and see that light just shows between the wire and the top of 
each roll; this wire should be drawn tight, from the top of the 
l)reast roll to the top of the guide roll. If the breast roll has been 
raised or lowered, the wire should be straight from the top of the 
breast roll to the top of the last table roll next the hinge or break 
in the table bars; see Fig. 27. If adjustments are required, they 
should be made by the millwright or master mechanic. 

119. Squaring the Other Rolls. — The couch roll and all other 
rolls must be kept square with the machine; periodical checking 
of the squareness of the rolls will often prevent undue strains on 
the wire. The upper couch roll should be so placed that a plumb 
line dropped through the center of the journal will be nearer to the 
wet end of the machine than a line similarly dropped through the 
center of the lower couch roll. Great care must be taken in 
couching (off-setting) the top roll. First see that the distance 
between these plumb lines is the same at the front, or tending, 
side of the machine as at the back, or driving, side of the machine; 
second, that the amount of couch is as much as possible, without 
taking the weight of the upper couch roll off the lower couch roll 
and placing it on the wire. An average amount for the couch is 
about 4 inches, but will vary with the size of the rolls. Sighting 
over two straight edges placed on the faces of both rolls front and 
back is a good method of checking your work. 

120. Amount of Stretch in the Wire. — The amount of stretch 
of the wire should not be tested by hand ; it is much better to use a 
mechanical tension indicator at the stretch roll, and an ordinary 
spring balance may be used for this purpose. Records of wire 
tensions so obtained and recorded will give valuable information 
as to the effect of various tensions on the duration of a wire. 
Take care not to stretch the wire too much. 

121. Starting a New Wire. — When starting a new wire, start 
slowly, have all the shower pijpes working and the hose going, so 


no stock can get between the rolls and the wire. Note whether 
the wire seam is raised up ; if so, pass it over the lower couch roll 
and flatten it lightly with a wooden mallet. If the seam is raised 
up, it will cause bubbles aci'oss the sheet, because of the air it 
traps as the raised part passes over the breast roll. This trapped 
air is forced through, and it makes its escape under the apron, 
carrying with it the frothy sizing compounds left by the waste 
water in the meshes of the wire. 

122. Lubrication. — Lubricant of a good grade, preferabl}' a 
clean mineral grease, should be used on the table journal bearings, 
and a mineral oil of approved brand, about 28° Be., on the other 
roll bearings. The wire, which acts as a continuous driving belt 
with the lower couch roll as the driving pulley, has a great load 
to carry, and this can be largely decreased by proper attention to 
the lubrication of the bearings. 


123. Souring the Wire. — If it can be avoided, do not clean the 
wire with acid; but if this appears to be the onh- effective method, 
dilute the acid with water — 5 parts of water to 1 part of sulphuiic 
acid. The solution can be apphed to the wire through the 
shower pipes on the inside of the wire. This process is called 
souring the wire. The weak acid solution may be applied on the 
wire as it comes over first wire roll. Alwaj's pour the acid 
into the water. 

A good way to clean a wire with an acid solution (sometimes a 
caustic solution is used for this purpose) is to make a water-tight 
box, in which the lowest outside wire roll can run. The roll, 
turning in the solution, will then sour the wire evenly all over, 
and the wire will, in its turn, carry around enough solution to 
sour and clean the whole wire. Be sure not to have the suction 
boxes in action while the cleaning process is going on; otherwise, 
the acid (or caustic) will then be lost before it reaches the dandy 
roll. When the wire and dandy stop frothing freely from the acid 
bath, they are practically clean; then wash off all the acid with 
a hose, and clean out the water-tight box. Keep this box clean 
or remove it. Remember that acid acts chemically on the wire, 
and that it must therefore be well diluted and afterwards 
thoroughly washed off. 


124. Pitch Troubles. — Pitch or grease spots in the wire may 
be removed by putting a strip of felt, about 36 inches wide, 
extending across the machine, on the inside of the wire; by 
means of a small jet or steam hose, about j inch in diameter, the 
pitch can then be blown from the wire into this felt. This 
arrangement gives a sharp, direct blow of hot steam at the 
pitch spots on the wire, which removes them so quickly that it 
does not heat the wire. Care should be taken not to hold the 
steam jet too long in one place, since this would weaken the 
weave on account of the resulting unequal expansion of the wire. 
It may be mentioned that alcohol and ether are solvents for 

While the stock is on the machine, pitch will sometimes accumu- 
late in the meshes of the wire or on the suction boxes. If on 
the suction boxes, the boxes may be removed while the wire is 
running; then remove the pitch and replace the boxes. 

125. Washing the Wire. — Wash the wire plentifully with a 
hose whenever a chance is offered; this keeps the meshes open, 
washes off the acid, prolongs the life of the wire, improves the 
appearance of the paper, and reduces the work on the suction 
boxes. Be careful, also, to play the hose well and carefully on 
the back side of the machine. Sometimes the dirt gets washed 
only from the front to the back side. Many of the troubles on 
paper machines are caused by the fact that the back side of 
the machine is not as easily taken care of as the front side; 
the machine tender should remember this when working on his 
machine, and should give special attention to the back side. 
The front side is not so liable to be neglected. When washing 
down with a hose, lift the dandy roll off the wire, so as to keep old 
froth spots from getting washed onto the dandy. Keep water 
off belts and motors, and remember that it costs money to pump 
water; don't waste it. 



126. Action of the Wire Guide. — ^The wire guide can prolong the 
life of a wire or it may shorten its life, according to its mechanical 
condition. If the guide mechanism is kept in good, sensitive 


working order, it will guide the wire without undue wear; but 
if it works stiffly, it ceases to be a protection and becomes a 
source of injury, by creasing and cracking the edges. 

127. Kinks in the Wire. — A kink in the wire, caused by 
dropping a wire brush or by any other means, can be removed as 
follows: First grease the kink, or buckle, bring the part of the 
wire where the buckle appears over the stretch roll, then sour or 
wash the wire with acid (a 4 to 1 solution of sulphuric acid) right 
across the portion of the wire where the buckle appears. The 
stretch roll can then be set up until the buckle, or kink, disappears; 
then wash off the acid solution with a hose. A kink can also be 
removed by the stretch roll, in a similar manner, b}^ heating the 
buckle or kink red hot, using a torch made of a handful of waste 
that has been dipped in kerosene and attached to a broomstick. 
The result of this is that the wire is softened and the kink is 
removed, instead of the wire being weakened by acid; and the 
strength of the wire is not impaired. 

128. Care of Apron. — If the apron cloth, frequently called 
the apron, will not lie flat, but tends to buckle or roll up on the 
edge, drench it with hot water until it lies flat on the wire. If 
the machine is idle for a long time, put a strip of wet felt on the 
edge of the apron; then fasten the brass or metal angles or side 
pieces to the apron, as far under the deckle pulley as is possible 
without touching the strap. See Art. 57. 

129. Necessity for Uniform Flow of Stock. — When starting 
the stock onto the machine, the slices should be so adjusted as to 
keep the level of the stock higher on the side next the apron 
than on the machine side; in this way, the speed of the stock is 
kept approximately as high as the speed of the wire for high- 
grade paper. If the stock is flowing onto the wire at a slower 
speed than the wire is moving, ripples and waves, the so-called 
fish tails, will appear on the stream of stock up to the point 
where the speeds are equal. If equality of speed be not attained 
before the paper is nearly formed, the increasing viscosity of the 
stock, as it gets drier, prevents the smoothing out of the surface, 
and these ripples or waves become permanent; the paper then 
lacks uniformity of strength, finish, and thickness, and it will, in 
such case, often break before it reaches the calenders. 

130. Regulating the Slices.— The sHces are regulated to suit 
the kind of stock and the speed of the wire. When the stock is 


fijie (or slow) and carries water well, the slices should be kept 
down, especially when making wove papery no more water should 
be used than is necessary to close the sheet, and as little shake as 
possible should be allowed. The suction box, or boxes, before 
the dandy roll should not draw too hard. 

When making laid paper, the slices are raised a little higher 
above the wire than when making wove paper; more water is 
required, more suction is necessary on the first boxes, and the 
stock is generally more free. The stock being more dilute, the 
head back of the slice (if the slice be not raised enough) will force 
the stock to move more quickly than the wire, and some of the 
effects of the shake will then be lost. 

When making light-weight papers, the tendency is to let the 
stock flow more slowly than the wire is moving. When this 
occurs, keep the stock back of the slices at a higher level, so as to 
create more head and get the necessary volume of stock for the 
same slice opening. 

When the stock is flowing too quickly under the slices, which 
is often the case when making the heavier papers, reduce the 
head back of the slices until the speed of flow is the same as the 
speed of the wire, by increasing the slice opening or by shutting 
off some white water. If the dandy roll tends to rise, there is 
too much water in the sheet; when this happens, increase the 
suction on the first boxes and give more shake. The thicker the 
sheet the more shake that is required. 


131. Manner of Running Stock. — When making envelope, 
cartridge, or any paper for which stock may have been kept too 
long, and is therefore soft, it is necessary to use plenty of water, 
raise the slices, and give a vigorous shake. Be careful not to 
give too much shake, or the edges of the paper will be thin, on 
account of the back washing from the deckle straps. 

It is sometimes necessary, due to the poor design of the flow 
box and apron board, to check the flow of stock at certain points 
across the slices, with pieces of paper, etc., so as to get an even 
stream across the machine. Weights are often placed on the 
apron, in the stream of stock, to correct such uneveness of flow. 
At the places where these obstacles occur, trouble may be expected 
at the dandy. It is better to correct for these faults by raising 


the slices a little, using more water, and increasing the flow from 
the box, 

132. If the stock is long, and is also soft from long storage, 
run slowly; but, even then, do not expect a good sheet of paper. 
When the stock is soft and fine, it will look crushed, and it will 
stick to the first press roll; use as little shake as possible and as 
much suction as possible. 

With soft, fine stock, weight the couchers well, and set the 
guard board close to the jacket, but keep the jacket wet enough 
to prevent rubbing off dust from jacket or board. Then use 
but little weight on the first press, and keep the wet felt fairly 
tight. If sticking still continues, use turpentine on the press roll, 
after the paper is down on the felt, and keep turpentine on the 
press roll until the tendency to stick and climb up the roll is 
sufficiently reduced, 

133. To Keep Water in the Stock. — In making a high grade of 
paper on a long wire, the paper may have a dull, crushed look, 
more especially if it be a wove paper, on account of too much 
water leaving the stock at the table rolls before proper formation 
is accomplished. To remedy this, prepare the stock fine, allow 
the water to stay in the sheet, and allow the shake to get in its 
work, by lowering a sufficient number of table rolls to keep them 
from touching the wire. It may here be remarked that some 
paper makers do not believe in the possibilities of judiciously 
varying the number of table rolls in action. 

It is to be noted that if the number of table rolls are reduced 
to the right number and the quantity of water is reduced to the 
right quantity, then the paper will reach the couch roll with a 
larger proportion of the sizing and loading originally placed in the 
beater than when more water is used and more table rolls are in 
action. It is common practice on high-speed news machines 
to remove several table rolls in the summer time, when the stock 
is freer, so as to prevent too much damage at the forming table. 

By raising the breast roll, saj^ 18 inches higher than the couch 
roll, a long wire can be used; this will carry the water well down 
to the suction boxes, and the machine can run at a speed of over 
800 ft. per min. on such papers as news. An even greater incli- 
nation of the wire is used at high speeds, up to 1200 ft, per min. 
If it be desired to use plenty of water to carry the stock well 
down the wire, and it is desired to close the paper well by using 


plenty of shake, the breast roll may be lowered, say 2 or 3 inches 
below the couch, and the amount of water may be used that is 
necessary when using a short wire ; fine papers can then be made 
at 100 to 300 ft. per min. 

134. Increasing Capacity of Machine. — By clear thinking 
and reasoning from the observed results of certain manipulations, 
the paper maker can largely increase the capacity of his machine, 
not only with respect to output and speed but also with respect 
to quality of finish and formation. He has control of the quan- 
tity of water and the amount of shake; he can, on the same 
machine, control the finish and felting by getting exactly the 
right amount of water out of the stock at the dandy roll; at the 
same time, he can have plenty of water in the stock at the slices, 
to allow the shake to get high speed and good felting. He can 
raise the breast roll and then correct the poor felting that may 
result therefrom, bj^ removing some table rolls; he can again get 
good felting by lowering the breast roll, and may still maintain 
his speed by increasing the head back of the slice and also increas- 
ing the number of table rolls. The amount of the suction on the 
first boxes gives him another instrument for increasing the 
efficiency of operation, and this is also under his control. How- 
ever, it is not practical or sensible to make experiments that 
would cut down production; unless the paper maker can estimate 
quite accurately what the result will be, it would be foolish to 

135. When starting the paper machine on a new order, examine 
the stock; if it is free, increase the water supply. If this be 
not done, the screens will fill up and the wire will be flooded with 
excess stock. On news, kraft, wrapping, and cheap book, start 
with plenty of water, say 300 parts of water to 1 of stock, and let 
the excess return to the regulating box, through the save-alls 
and white-water pump. 

On slow stock, — rag paper, fine writings, ledgers, bonds, etc., — 
it is best to start with about 50 parts of water to 1 of stock, and 
then gradually increase the water supply, if found necessary. 

136. Regulating the Suction. — If the stroke of the shake be too 
long, the stock will wash back from the deckle straps, thinning 
the edges and causing a mark about 2 or 3 inches from the edge 
of either side. Search between the slices and deckle straps for 
causes of feathery edges; these may result from striking of the 


deckle straps against the slices. See that deckle straps have 
clean, square edges, and that they rest flat on the wire. 

There should be a sufficient number of suction boxes on the 
machine to keep too much water from getting over to the couch 
rolls. It is well to use only about 7 inches of vacuum on all the 
boxes; but if there are not enough boxes, a greater vacuum must 
be used, in order to do the work. Bear in mind, however, that 
when 10 inches or more of vacuum is used, the life of the wire will 
be shortened. There should be at least 4 suction boxes. Too 
much suction on the boxes will sometimes prove to be an excessive 
load, and cause the lower couch roll to slip on the wire. If the 
box covers are of wood, see that the}' are planed smooth, so the 
wire will not be forced to follow the ridges it makes in the covers ; 
also see that the box covers are thick enough to keep them from 
vibrating when a strong suction is carried. 

137. Froth. — When making soft-sized paper, froth is liable 
to cause trouble; in such case, lower the slices and use more 
water, so the froth is kept back of the slices. Small bubbles 
sometimes escape down the edge along the deckle straps; this 
may be prevented by using a piece of paper, folded where the 
straps and slices meet. The bubbles that gather on the edge 
of a laid dandy roll can be kept away by rubbing a little oil on the 
dand}', just off from the edge of the paper, or by oil ng the wiper 
cloth, just over the edge. Do not spend money on patented 
froth-killing mixtures. A good formula is a mixture of lin- 
seed oil and bleach, half and half (1 to 1), with about a pint of 
turpentine added to every 5 gallons of the mixture. 

138, Kerosene is also a good froth killer. Either kerosene 
or the mixture just mentioned can be advantageously used by 
suspending it in a o-gallon can over the suction of the white- 
water pump. The drip of the froth killer should be at the rate 
of about 5 or 6 drops per minute. This can be controlled either 
by soldering a small radiator valve to the bottom of the can or 
simply by punching a small hole in the can and passing some lamp 
wick through it, so the hole can be plugged entirely by the lamp 
wick, if desired, or as nearly plugged as is necessary. Some- 
times this froth-killing mixture is dumped into the beaers before 
emptying them ; about | pint of the mixture to a 1 200-pound beater 
is sufficient. A good spray, preferably rotating or oscillating, over 
the pond or over the flow box is usually very helpful. 


To keep the dandy roll free from froth when making laid 
papers at high speed, place a perforated pipe in front of it, so a 
little steam may be blown across the surface; this will keep it 

139. Enlarging the Watermark. — Sometimes it is necessary to 
have the watermark in the paper slightly larger than the size of 
the marks, or the distance between them in the paper must be 
slightly greater than the spaces on the dandy roll; in such cases, 
either the mark must be stretched or the paper must be stretched. 
First let the wiper cloth bear sufficiently hard on the dandy to 
slow it up; not so hard as to cloud the mark, but just enough 
to gain a little. Then speed up the first press somewhat, to get 
a little more stretch, and do the same at the second press. In 
this manner, a dandy mark may be stretched a full eighth of an 

Lack of uniformity in the dandy marks across the machine, if 
the dandy is straight, is probably due to improper crowning of 
the press rolls, which makes the paper either wetter at the ends 
than in the middle or the reverse of this. When the paper is not 
uniformly pressed, the wetter parts are stretched more on the 
dryers than the drier parts. When setting a dandy, be careful 
that the deckles and markings are right ; that is, set it so that the 
edges of the paper come the proper distance from the marks. 
Count the circumferential bars on the dandy, from the edge of 
the paper to the mark, and make the number equal on both 


140. The Couch Roll. — Be certain that the upper couch roll 
is not couched too much; in other words, be sure that the weight 
of the upper couch roll is carried entirely by the lower couch roll, 
and that no part of its weight is carried by the wire. 

In a perforated roll, the holes keep water and wool balls from 
collecting under the jacket, and thus causing the jacket to creep 
and move around the roll. These holes may convey quite a Httle 
water into the inside of the upper couch roll, the water being 
squeezed out by the nip between the rolls or by the squeeze 
action of the guard board. This water is drained out of holes 
in the head of the roll, and is led away. An old upper couch 
roll M'ill, in time, accumulate enough slime and refuse on its 


inside, from these holes, to cause trouble by getting the jacket 
spotted, and so dirtying the paper. Although this rarely 
happens, it is sometimes a cause of trouble, one that a paper 
maker might not think of, unless it had occurred in his previous 

141. Putting on a New Jacket. — ^When putting a new jacket 
on the couch roll, have a jacket of the right size for the machine 
and of the right character for the kind of paper to be made. The 
felt maker should be given full information as to the requirements 
to be met, and he should also be fully informed regarding any 
defects in the jacket and of any difficulties encountered while 
the jacket is in use. 


Fig. 47. 

The old jacket is cut lengthwise, and the wire is driven forward 
until the jacket is clear. The new jacket is opened on the clean 
machine floor and carefully measured. Should it appear a trifle 
small, it can be stretched a little on a stretcher, such as is shown 
in Fig. 47. The hard-maple beams A, rounded on the outside, 
over which the jacket is stretched, are supported clear of the 
floor, and they are pushed apart by the toggle joints T, by turning 
the nut N against the yoke Y. This can be done while the upper 
couch roll is being prepared. There are several designs of jacket 

When the ends of the jacket are held tight by clamping rings, 
screwed or bolted against the end of the roll, or if the jacket is 
sewed fast, each end is punched, about 3 inches from the edge, 
with a row of j-inch holes, about 6 inches apart, and threaded 
with stout twine. 

Take off the shower pipe and guard board, or lift it clear; 
also, the guard rail, if there be one. Remove weights and levers, 
and lift the upper couch roll well clear of the lower roll and the 
wire. Be very careful not to walk on the wire or drop anything 
on it. Clean the roll thoroughly, inside and out. To prevent 


sweating of the roll, pour a few pailfuls of hot water on it, and 
wipe it dry just before putting on the new jacket. 

SHp the new jacket over the lifting or porter bar used for 
putting on the wire, making sure that the nap shall be smoothed 
down as the jacket runs under the guard board; fit the open end 
of the bar over the extension of the upper couch-roll journal, 
on the front side, and hft the free end with the chain hoist. 
When the weight on the bearing is relieved, remove the bearing 
cap, and swing the bell-crank lever out of the way. 

142. Couch-Roll Jackets. — The couch roll on a Fourdrinier 
serves two main purposes: the first is to transfer the paper from 
the Fourdrinier wire to the felt ; the second is to squeeze out as 
much water as possible in the process. Consequently, in order 
to withstand this great pressure, the jacket must be very strong 
and firm; if it does not have the proper strength, this pressure 
causes it to become loose and to get baggy on the roll. 

The older practice was to use a jacket on both top and bottom 
rolls, and this practice is still carried out in a few mills making 
very high-grade paper at slow speeds. At the present time, 
however, in most mills where jackets are used, only the top roll 
is jacketed. 

Couch-roll jackets are woven in tubular form; this necessarily 
makes the production slow, since a great many threads must be 
woven to a single inch in a loom. These tubes are in lengths 
sufiicient to allow several jackets of the same diameter to be cut 
from one tube, when finished. 

When finishing jackets, all sizes are pulled to a diameter some- 
what smaller than the diameter of the roll on which they are to 
be used. They are stretched while wet to a size that allows 
them to be slipped over the roll; and after they have been dried 
on the stretchers, this size is held until they are again wet up on 
the paper machine. When the water strikes the jacket, it 
tends to shrink back to its former size, thereby hugging the 
couch roll tightly. 

The guard board has more to do with the length of service 
received from a jacket than any other one thing, since undue 
pressure on the guard board causes the jacket to wear very 
rapidly, and it has a tendency to make the jacket become loose 
and get lumpy on the roll. Guard boards should have a beveled 
edge and should be kept in good condition. If the jacket be 
shrunk on evenly and firmly at the start, and if proper care be 


exercised regarding the pressure applied to the guard board, 
good results can usually be obtained. In late years, many of the 
news mills have been obliged to use a considerable percentage 
of jack pine in the manufacture of their paper, the pitch from 
which often accumulates on the jacket. If this pitch is not 
washed off with proper care, the life of the jacket is often very 
materially reduced. 

Now with everything clean and clear, carefully draw the jacket 
over the roll until it overlaps the same distance on either side. 
Replace front bearings and remove lifting bar; draw up quickly 
and strongly on the twine threaded into either end, avoiding 
wrinkles, and tie in a knot that will not slip. Another method 
of fastening the ends is described in Art. 143. Lower the roll 
until it makes firm contact with the lower roll; and if a clamp be 
used to hold the jacket, screw or bolt it firmly in place. 

143. Couch-roll jackets get worn more quickly at the edges 
when the ends are so fastened to the head of the roll that the 
jacket is held at these points, although it may slip at the center. 

Couch-roll jackets are often fastened __^ j 

by sewing crisscross, across the heads, 
with stout packing thread, A better 
method of fastening the ends is to 

make a wood disk, Fig. 48, shaped ' 

on its edge like a frustum of a cone, ^^°" ^^' 

to which the ends of the jacket are fastened with copper nails. 
This ring is not fast at the roll; so if the jacket slips a bit, the 
ring turns with it, and the jacket is not strained. Couch-roll 
jackets that are clamped to the couch-roll heads with bolted 
metal plates do not last long. 

Having fastened the jacket, replace shower pipe, guard roll, 
and guard board, the edge of the latter having been planed to a 
true straight edge by the millwright. 

144. Shrinking the Jacket. — The jacket must now be shrunk, 
to grip the roll tightl}^; this is accomplished by pouring several 
pails of very hot water across the roll ver}^ quickh^; then start 
the wire, to turn the roll and enable any dry places on it to be 
wetted. When the jacket is firmly set, check further shrinking 
by starting the cold-water shower. Lower the guard board 
carefully, and set its edge so the jacket will be uniformly dry for 
its full length; use as little pressure as possible. 


145. Starting a New Jacket. — AVhen starting a new jacket on 
fine stock that is liable to stick to the nap. use as little weight on 
the roll as possible, and put the guard board down fairlj^ tight. 
Before starting, pour a few handfulls of white clay or filler on the 
jacket, while dry, so the nap may be flattened and the jacket 
made harder by closing the pores with the clay or filler; or use a 
solution of soda ash in boiling water for the same purpose. 
When starting the roll, no water should be run on the roll, but 
a little clay may be put on it. When the shower on the working 
edge of the guard board is turned on, the pipe should be so turned 
that the jets will play on the front of the guard board, the water 
running down the front onto the jacket. If the jets play on the 
new jacket, the nap will rise, and the liabihty of -picking up the 
paper will be much greater. But if the paper should pick up, a 
little turpentine or rosin size poured on the jacket will stop this. 

146. Jacket Troubles. — A new jacket often causes trouble 
when colored papers are being made, since the picking up of 
fibers causes marks on the surface of the paper. If the guard 
board allows water to pass, the jacket will pick up stock as it 
runs onto the wire. Brushes that have been weighted with lead 
and placed on the jacket in front of the guard board, will keep 
the jacket clean; or the trouble may often be obviated b}^ a 
vigorous rubbing by hand. For brushing jackets and felts, a 
brush of fine brass wire, or a piece of woolen-mill card, may be 
used. Turpentine is good for cleaning the edges of the couch 
roll; here the picking up is w'orst, which may be due to the dams 
in the suction boxes being too far from the edge of the paper. 

147. If the jacket seam is not straight, that is, if it tends to lie 
diagonally across the wire, it may be straightened by increasing 
the couch-roll weights on the side where the seam is traveling 
ahead; this will produce a drag on this side of the wire, which will 
straighten the seam. Adding weight in this manner may, how- 
ever, cause lumps of wool to gather inside of the jacket, and it 
may also make the paper thinner on one side; it is not the best 
practice to have the weights uneven to any extent. 

The machine tender should be careful not to allow the upper 
couch-roll jacket to slip or twist. Should this occur, reduce the 
pressure of the guard board as much as possible and adjust 
weights on the upper couch roll, by easing up on the side that 
begins to lag behind. If the jacket gets so loose at the center that 


it wrinkles because of a crown on the lower roll, take off the guard 
board and end clamp, and stretch the jacket into place. 

When using a pressure roll, watch the lower couch roll; if 
there is too much suction on the boxes, the lower couch roll will 
slip in the wire. 

148. A Patented Jacket. — Most jackets are woven endless 
tubes of high-grade wool, usually hard but fine. An English 
jacket that finds considerable favor is felted instead of being 
woven; it therefore has no warp, and it is the same all through and 
in all directions. Special care must be taken not to pull or 
wrinkle these jackets, with the guard board or otherwise. 


149. Amount of Suction.^ — As previously stated, some machines 
have pressure couch rolls, while others have suction rolls. In the 
case of a suction roll, the operator must be careful not to get 
too much suction in the suction boxes; for, if this occur, it will 
cause the wire to be slack after leaving the suction roll, and the 
wire will wrinkle. The best way to determine how much suction 
to use is to watch the wire after it passes the suction roll; if the 
wire gets slack, reduce the suction on the boxes until the slack 
wire below draws tight enough to run safely without wi'inkling. 
On free stock, such as news, cheap tablet, catalog, wrapping, 
etc., it is practically impossible to get too much suction, because 
air penetrates the sheet easily. 

150. Braking Efifects. — The action of the suction boxes in 
drawing the wire down to the surface of the box, results in a 
brake effect on the wire. The greater the suction the greater 
this brake effect, which must be overcome by an added pull by 
the surface of the lower couch or suction roll, to drag the wire 
away from the suction boxes. The couch roll will sometimes slip 
under the wire, if the load it pulls is too great; this may break the 
paper on the machine, because of a momentary variation in the 
speed of the wire, unless the machine be driven by a sectional 
electric drive. The doctors on the breast roll and other rolls can 
also act as brakes. Anything that the machine tender can do to 
reduce the amount of pull on the wire by the couch roll, without 
spoiling the paper-making function, will increase the life of the 


151. Making the Wire Run True. — If. the machine tender find 
that the wire guide will not keep the wire true, and the wire 
tends to travel to one side, then, provided the rolls of the machine 
are square, the trouble may be in the suction boxes. The wire 
will wear grooves in the suction-box covers, and sometimes the 
wire jumps the grooves, which causes it to be led to one side. 
When this occurs, the guides cannot help matters; the only 
remedy is to cut off the vacuum, by shoving in the rods, slacking 
the supporting bolts, and moving the box so the wire will not enter 
the same grooves. However, it is better, if possible, to take out 
the boxes and plane the covers. 


152. The Showers. — The patented shower pipes use less water 
per minute and, at the same time, throw a stronger stream; that 
is, a shower pipe that has had some thought expended on its 
design is not only more economical of water but it also does its 
work better. A rough figure that is approximately correct for the 
old-fashioned shower pipes, operating under 35 pounds water 
pressure, is 1| gallons of water per minute per inch of width of 
machine; the modern, patented shower pipes will save about one- 
third of this water. 

If the shower pipes are not doing good cleaning work, increase 
the water pressure, if possible, and keep the holes clear. Use 
filtered water. The effect of an increase of water pressure on the 
shower pipes is to increase the force of the showers, it also 
increases the consumption of water. For instance, a 48-hole, old- 
fashioned shower pipe, 1| inches in diameter, with iV,-inch holes, 
spaced | inch between centers, showed the following water 
consumption : 

At 10 pounds pressure, 13.3 gallons per minute 
At 20 pounds pressure, 15.5 gallons per minute 
At 30 pounds pressure, 18.2 gallons per minute 
At 40 pounds pressure, 21.6 gallons per minute 
At 50 pounds pressure, 25.0 gallons per minute 

In selecting the spray pipe, the nozzles that give the finest 
spray, and which throw the spray so it falls over a large area of 
froth, should be selected. These pipes are generally located 
over the flow box, over the apron, and just back of the slices, 
their sole duty is to reduce the accumulation of froth. 




153. White Water. — The water that drains through the 
Fourdrinier wire, and which is often increased in volume by 

S^ock in Stuff Chesi) 
, (37% -96 7o Wafer 3% -B 7o Fiber) 



A-t Re,gu/ah'n/j Box. V/'aShffR/mp 

Ai' Screens 


(Same as Above) 

Wblh Water Added 

(39 7o-9S.S7o Water) 
l7o-0S7o Fiber 

At Flow Box 

(Same as Screens) 


A-f- Forming Table 

(Same as Flow Box, Loses White Wafer 
to Save- Alls Boxes, Leaving Sheet 
ofFbper on Wire) 


Y White Wafer to Fan Pump 


At Suction Boxes 
( About 937o -967o Wafer) 


Y White Wafer to ^ 

Fan Pump or Fiber Recovery 

Besh Wafer to Fan Pum p- 

When Needed 

At- Couch Rolls 
(About 907o-927o Wafer) 

Y White Water to Fiber Recover,ij or to Waste 


At Wet Press 

(About 857o -907o Wafer) 

Fig. 49. 

water from showers, is called white water, back water, or 
re-water; it may also be water from the suction boxes and couch 
rolls. This water contains considerable fine fiber and mineral 


matter. Most of it is lifted by a suction pump, and is used to 
dilute stock passing to the screens. What happens to the water 
in stock at the wet end of the machine is shown in the chart, 
Fig. 49. It is to be observed that about 50% of the water 
removed at the Fourdrinier part leaves the paper at the table 
rolls, with about 25% taken out at the suction boxes and 25% 
at the couch rolls; this leaves still 90% of water in the sheet 
going to the presses. Reference should be made to the diagram 
in Art. 21. 

154. Mesh of the Wire. — By mesh is meant the number of 
wires or openings to the inch. The wire used for coarse papers, as 
news or wrapping, is ordinarily 60- or 65-mesh; for writing or 
book papers, it is generally 70-, 75- or 80-mesh ; while for special 
papers, as cigarette, a much finer mesh is required. 

The alloy used for weaving Fourdrinier wires must be strong, 
tough, and flexible enough to weave into a flat cloth, and must be 
fairly resistant to acids. Extra wires are used at the edges, to 
give greater strength and wearing qualities. An alloy commonly 
used is 80% copper and 20% zinc. Phosphor-bronze wires are 
now used almost exclusively on newsprint machines. 

155. Starting the Wire. — The following directions for starting a 
new wire have been condensed from Witham's "Modern Pulp 
and Paper Making:" 

Great care must be exercised in starting a new wire, first being 
assured that everything is in proper condition before striking in 
the clutch, which operation should be performed very gently. 
A clutch should never grip so hard that the wire is started with a 
jerk. It is found to be a very good plan to turn the wire around 
slowly, at least once or twice, before the couch is set down, thus 
getting the wire in proper alinement before setting up. The 
stretch roll must not be tightened down until after the top couch 
roll is lowered into place. 

The seam of the wire should be watched closely, so that neither 
end will run ahead of the other, but shall line up with the suction 
box or a parallel roll. All particles of hard material must be 
brushed and rinsed off before the wire is started up. 

If for anj' reason the wire is stopped and the stock is shut off, 
the shake should also be stopped, since there is danger of shaking 
the wire into a wrinkle when it is not loaded with a sheet of paper 
and held down by the suction boxes. If anything happens that 


makes it necessary to strike the wire out immediately, without 
first having a chance to shut off the stock, such stock should be 
thoroughly rinsed from the wire before attempting to start again. 
The weights should be removed from the couch levers, and, by all 
means, the suction should be broken where the stock has sealed 
the wire over the top of the suction boxes; this can be done by 
rinsing, or by rubbing the fingers across the top, to break the 
suction by letting air in. 

Care should be taken to let up on the guard-board screws before 
striking the wire in, since the couch-roll jacket is frequently torn 
off by neglecting to do this. The guard board should never be 
let down onto the jacket until after the weights have been applied 
to the couch rolls; there is always enough slack in the couch-roll 
boxes, so that if the guard board is let down before the weights 
are apphed, this slack is taken up in the boxes, and the guard 
board will necessarily have to carry the weight of the weights on 
the levers. In setting the guard board, great care should be 
taken to lower it horizontally, never allowing one end to go down 
before the other; otherwise, the jackets would be torn from the 
couch roll. 

Stock should never be allowed to pile up high enough in the 
save-all to touch the wire. 


(PART 1) 


(1) Name some advantages to a student in keeping a notebook. 
What might be put in it? 

(2) Name the principal parts of a Fourdrinier paper machine 
and mention briefly the function of each. 

(3) Explain fully what happens to the stuff in the stufT chest 
until it reaches the paper machine. 

(4) What is the other function of the water used to carry the 
paper fiber onto the wire? 

(5) What happens to the paper if the excess water is not 
removed before the paper reaches the couch rolls? 

(6) Explain a cause, and mention a remedy for (a) slime spots, 
(h) "fish tails," (c) thin edges, (d) crushed paper, (e) dandy 

(7) Describe the course of the water used at the wet end of a 
paper machine. 

(8) Name some points 3'ou would insist on in ordering a stuff 
chest, and tell why. 

(9) Explain the purpose of the regulating box. 

(10) What is the characteristic of paper pulp on which the auto- 
matic regulation of stuff is based? 

(11) (a) If you were building a mill would 3'ou install a save- 
all? Why? \h) What kind would you select? Why? 

(12) Explain the operation and advantage of (a) a flat screen; 
(6) a rotary screen. 

(13) Tell briefly the story of the invention and development of 
the Fourdi'inier machine. 

(14) Where are the following parts and what are they for: 
(a) flow box? (6) shake? (c) dandy roll? (d) guard board? 
§6 97 


(e) apron? (J) deckle straps? {h) guide roll? (z) suction box? 
(j) stretch roll? (k) slice? 

(15) (a) What is the function of the couch press? (6) How 
is this accomplished in the case of a suction couch roll as com- 
pared with the ordinary couch press? 

(16) Explain the action of table rolls in the removal of water 
from the paper. 

(17) (a) What effects are produced on the stock by raising or 
lowering the breast roll? (6) using more or fewer table rolls? 

(18) (a) Why is it necessary to have rolls square with the 
machine? (6) how are they tested? 

(19) What is the difference between a left-hand and a right- 
hand machine? 

(20) How is the paper taken from the wire to the first press 



(PART 2) 



156. Passing to the Press Part. — At this point, the reader is 
requested to turn back to Art. 52, where the cut squirt is described 
and also the method of passing the paper by hand from the couch 
roll to the wet felt. It is well to note here that the paper can be 
picked off the wire by a rough felt and automatically placed on 
the first wet felt. This small auxiliary felt need be only a little 
wider than the strip of paper cut by the cut squirt; it may be 
carried on two or three rolls in a frame that can be moved to 
place the felt in contact with the wire and the first press felt. 
The onl}^ necessary condition is that such an arrangement be 
adjustable and removable; also that the small felt be rougher and 
more porous than the wet felt. The paper may be blown from 
the couch roll to the wet felt, that is, the narrow, squirt-cut strip 
can be so blown. A successful method of accomplishing this is 
to have the blowing pipe from which the air jets strike the wire 
at or near the edges of the narrow strip cut by the squirt. The 
paper is thus lifted down from the wire, and its momentum, 
aided by the air current, carries the strip across to the first felt. 
With a suction couch roll, the jet of compressed air may be 
directed from within the roll. 

157. De-watering Devices. — Up to this point, the paper has 
been de-watered as follows: the Fourdrinier part of the paper 
§6 99 



machine partly de-waters the paper by the action of the table 
rolls, which causes the water to drain out through the wire; 
when this process has gone as far as possible, the next step is the 
use of suction boxes, which suck out the water; the dandy roll 
smooths the surface a little, and when the paper has passed over 
the suction boxes, it has become strong enough to be squeezed 
in the couch rolls. After having passed through the couch 
rolls or over the suction roll, the next de-watering device is 
through the use of pressure; and as the paper passes from the 
wire to the wet felt, as much water as possible is squeezed out 
in the presses. 

158. Per Cent of Stock and Water at Different Stages.— The 
following table shows the per cent of stock and water at various 
stages, from beaters to dryers: 



All sulphite 

(600 ft. per 

(300 ft. per 

(400 ft. per 










Mixture from beater. 







Mixture goipg on wire 






Entering couch rolls . . 







Leaving couch rolls . . . 







Leaving last press .... 







Leaving dryers 







1 It is claimed that, with a suction roll, the solids here will be 15%. 

Water does not leave book paper as readily as it leaves news; 
hence, book paper leaves the Fourdrinier and enters the dryer 
part carrying a greater per cent of water than news does. The 
per cent of stock on book paper will be approximately the same as 
on papers where bleached sulphite stock is used. Water leaves 
paper made of unbleached sulphite more readily than from any 
other that has had the same preparatory treatment; therefore, 
more water can be pressed out by the couch action and also by the 
presses, the felts do not fill so easily, and a greater pressure can 
be applied on rolls. This grade of sulphite paper leaves the 
presses dryer than either news or book papers. 




159. Referring to the sulphite part of the table, it is apparent 
that if the ratio of solids to water at the breast-roll end of the wire 
is 1 to 99, then it will take 9900 pounds of water to make 100 
pounds of paper. In practice, somewhat less water is required, 
because the paper leaving the 
machine is not bone dry; it still 
contains about 7% of water. In 
calculating the amount of water 
necessary for the machine, there 
should be added the amount of 
water required for showers and 
washing; and there should be sub- 
tracted from the total initial supply 
of pure water estimated as necessary 
the amount of white water returned 
through the save-alls, fan pump, and 


160. Purpose and Limitations.— 
The press part consists of a series 
of press rolls, through which the 
paper passes. The object of these 
presses is to squeeze out of the paper 
as much water as possible, without 
injur}'- to the paper. While it is 
cheaper to remove the water by 
pressure rather than b}' evapora- 
tion, up to a certain limit, it is 
practically impossible to dry paper 
or pulp by mechanical pressure be- 
yond the point where it has less 
than 60% of contained water; in 
fact, it is very unusual to find a 
press part on a paper machine 
that deHvers paper at the dryer 
end containing less than 66% water, the remaining 34% being 
paper stock. 

161. Course of the Paper. — The paper in the press part is 
convej-ed on felts through the nip of the presses. The lower rolls. 


unless suction rolls, of the presses are rubber covered, and the 
upper rolls are made of hardwood or stone, cast iron or have a 
bronze outside casing. Fig. 50 shows a press part for high-speed 
news, which consists of three presses, the paper being reversed 
on the third press. Where only two presses are used, the paper 
is reversed at the second press. 

The machine tender passes the paper from the couch roll V 
onto the felt of the first press at roll U; the felt carries the paper 
over the suction box Bi; from thence, it travels over a felt roll 
that is so placed that the felt and paper run down toward the 
nip of the first pair of press rolls Ki and Ko. This arrangement 
keeps the water that is squeezed out Ijy the press rolls from 
running onto the incoming felt and paper, since it is thereby 
forced to run down the near side of the lower press roll. This 
position of the felt roll also keeps air from being pocketed between 
the paper and the felt. The platforms P and Pi allow the 
machine tenders to cross the machine. 

162. As the paper passes through the first press, it leaves the 
felt and clings to the first upper press roll until it reaches the 
doctor Di, by which it is scraped off and where it accumulates as 
wet broke in an inchned V-shaped trough, which is formed by the 
doctor blade and the back retainer wall that is built onto the doctor. 
This broke, or waste paper, is sent back to the beater room. 

The bottom roll of the first press is covered with rubber; the 
upper press roll is of wood (maple), cast iron, cast iron with a brass 
sleeve, or stone (polished granite), the brass sleeve and stone rolls 
giving the best surfaces for enabling the paper maker to skin the 
paper off the upper press roll before lajdng it on the felt. The 
felt carries it forward, and it is passed bj^ the machine tender 
from roll Ei to roll E2, on its way to the second press. 

When the machine is provided with a cut squirt, this is set to 
give a strip from 3 to 6 inches wide. This is peeled off the upper 
press roll bj^ picking the edge with thumb or finger nails, or 
blowing it off b}^ compressed air; sometimes it is laid over a small 
roll, and placed on the felt, against which it is held until the 
drag of the felt is sufficient to pull the paper from the roll. It 
is fed into the nip of the second press and the cut squirt pushed 
across the wire. Sometimes this strip, widened to 8 to 10 inches, 
is carried well over the dryers before the full tail is cut. 

If a cut squirt is not used, the machine tender gets as much 
as he can pull away from the front edge, then the back tender 


peels the remainder gradually away until the paper is all on the 
felt. A prolific cause of profanity! 

After leaving roll Ei, the felt passes around felt rolls Fi, F2, 
Fz to stretch roll C\', then over guide roll G\, to felt roll Fa, under 
shower pipe J\, past whipper Ti, to roll U. The course of the 
other felts may be ti-aced similarly. In Fig. 50, the felts are 
indicated by full lines, and the paper is indicated by dotted 

The doctor Di, etc. is liable to scrape grooves into the upper 
roll; for this reason, it is supplied in many cases with a vibrating 
mechanism, which will be described later. 

163. Course of Press Felts. — Before leaving the first press 
and following the course of the paper, observe how the first-press 
felt gets back to the first receiving roll. The first-press felt is a 
long one, and the extra length is sometimes carried to a roll in 
the basement. The first felt must be of rather open weave, to 
allow the large quantity of water that is squeezed out at the first 
press to pass through it. The second felt is generally finer than 
the first felt, that is, it is softer and has more nap, so as to produce 
a smoother finish on the paper as it passes through the nip of 
the press roll. According to the kind of paper being made and the 
treatment that the felt receives, the first felt becomes hard in the 
course of a few weeks, or even sooner. The pores are filled with 
filler that will not wash out, or the pores are forced to assume 
diamond shapes by the irregular stretch of the felt; as a con- 
sequence, it is usually necessary to remove the felt before it is 
worn out. But such a first felt is still good enough to use on the 
second press. For this reason, it is the general practice on news 
machines so to design the first-press part that the felts used on it 
are of the same length as those on the second press. In the 
design shown in Fig. 50, the felt on the second press is long, 
because the paper is reversed at the third press, and this necessi- 
tates that the second-press felt travel the full distance under the 
third press. The felt stretcher Ci is actuated by the hand wheel 
Hi, by means of a sprocket chain and two sprocket wheels, in a 
manner to be described later. 

It should be noted that some felt rolls have the felt lapped 
around them, so they may have two portions of felts pulling on 
them in the same direction; it is evident that such rolls have a 
greater pull exerted on them by the felt than those which the 
felt simply passes over. The latter rolls do not need to be as 















2 A 





large or as strong as those having the felt wrapped half way 
around them. 

164. Size of Felt Rolls. — The usual sizes of felt rolls and their 
journals for different widths of machines are given in the following 
table, all dimensions being in inches: 

Width of machine 100 

Sizes of rolls 6^-7 

Sizes of j ournals 1 1's 

165. Course of Paper (Continued). — The machine tender, or 
the back tender, passes the paper from the first-press felt, as the 
felt turns down on felt roll Ei, to the second-press felt, as it 
turns up on felt roll E2. The paper is carried by the second-press 
felt over the felt suction box B2 (not always used), and over the 
felt roll, which is raised above the nip of the second press, in 
exactly the same manner as it passes to the first press. The 
doctor, the press housing and arm, the weights and levers, the 
stretcher roll C2, and the guide roll G2, are the same in all respects 
as those of the first press; the course of the felt, however, is 
different, as will be seen from the illustration. 

The paper is to be reversed at the third press, in order to 
bring the wire side against the upper third-press roll, so the 
impressions of the wire may be removed by the smooth surface 
of the upper third-press roll. To carry the paper far enough 
forward in the machine to allow of its return in the reverse 
direction through the third press, it is necessary to make the 
second -press felt carry the paper to roll E3. The machine tender 
takes the paper from the second-press felt at roll E3, passes it 
over paper rolls Mi and M2, and places it on the third-press felt 
at roll N. If the paper were to pass direct to roll N, it would 
break. The paper rolls Mi and M2 give the paper plenty of 
slack and allow enough give and take in the pull of the third- 
press felt to permit the paper to be laid on this felt without 
undue strain, with its consequent breaks, since the narrow tail of 
wet paper is very weak. 

At the third press, the paper enters the nip of the press rolls 
from a felt roll whose top is higher than the nip. The paper is 
carried around by the face of the upper press roll in the third press 
in exactly the same manner as in the other two presses, because 
it sticks to the surface of the roll until it is scraped off by the 


doctor D3, where it forms wet broke. The tail is skinned off the 
press roll by the machine tender, who passes it over the paper 
roll M3, which is so supported by brackets that it is higher than 
the top of the upper press roll. From this point, the paper is 
passed over to the dryers. Skinning the narrow strip of paper 
from the roll requires skill and practice. Unless the machine 
is provided with compressed air nozzles, the edge is broken by 
the finger nail, quickly torn across, then pulled away, and the 
strip carried forward, over the paper-carrying rolls, and passed 
to the smoothing press or the first dryer. 

If the machine has no cut squirt to cut the narrow lead strip, 
or tail, this is torn by the back tender or third hand as the 
paper passes from roll Mi to roll M2. He pushes his fingers 
through the sheet about 6 inches from the front edge and gently 
pulls away a narrow strip, skillfully keeping the tear vertical 
till the paper is safely on the dryers, when he gradually works 
the tear across the paper, finally breaking through the back 

166. The third-press felts pass around the stretch rolls C3, the 
guide rolls G3, and the felt rolls Fj, etc. On some machines, 
there is a very light belt from the felt rolls to the paper rolls; 
and the pulleys may be heavy enough to act as flywheels. It is 
decidedly advantageous to use ball bearings. An English patent 
provides for driving the bearing, which, in turn, imparts motion 
to the paper roll. When not so provided, it is usually necessary 
to start the rolls turning by hand. 

Fig. 50 shows the characteristic features of a press part of a 
paper machine, including the reversal of the paper, which is 
generally done at the last press, regardless of whether there are 
two presses or more than two. The reader should study this 
drawing carefully, making himself so familiar with the run of the 
felts that he can see them in his mind, as it were; he should make a 
practice of sketching from memory the run of felts on paper 
machines; unless he is perfectly familiar with this detail, he 
cannot expect to understand press-part problems, which are 
frequently coming up for discussion and solution. 

There is a slight increase in surface speed at each successive 
press, from presses to drj^ers, and from dryers to calenders; this 
increment is called the draw, a term also applied to the unsup- 
ported paper passing from one part to another. 





167. Types of Press Housings. — Fig. 51 shows typical sketches 
of four different designs of press hovisings; designs (a) and (6) 
are for use on light, narrow machines, while designs (c) and (d) 

Fig. 51. 

are for use on heavier, wider machines. These designs will now 
be considered in the order named. 

The housing (a) has a swinging arm B, pivoted at P on frame 
F, which carries the journals J of the upper press roll K. The 
lower press roll Ki is supported by journals in separate bearings 
on the press frame, as indicated at Ai, A 2, A-.^, Fig. 50. Arm B 
is raised or lowered by turning hand wheel W, which turns screw 
S through the pivoted nut A'^. The reader will note that this is 
a lever of the third class. 

In the case of the housing shown at (6), the operator raises or 
lowers the arm L carrying journal J of the upper press roll iC by 

§6 THI^] PRESS PART 107 

turning the hand wheel here indicated by the circle W. The 
shaft of this hand wheel carries a worm G, which meshes with the 
worm gear N; the latter acts as a stationary nut, and raises or 
lowers the hfting link S, thereby moving the swinging arm L 
about the pin P. F isa felt roll, and H isa hook for attaching the 
levers to put extra pressure on the upper roll. (See Wi, W^, and 
Ws, Fig. 50.) 

In the case of the housing shown at (c), the swinging arm L is 
raised or lowered by means of the hand wheel W; this housing is 
the reverse of that shown in (6). The bevel gear G on the hand- 
wheel shaft meshes with a larger bevel gear N, which acts as a nut 
and screws the lifting screw S up or down, thus raising or lowering 
the upper press-roll arms. 

In the housing shown at (d), the swinging arm L (a bell crank) 
carries the upper press roll K, and is raised or lowered by means 
of a hand wheel, which is here indicated by the dotted circle 
W. A worm wheel G is keyed to the hand- wheel shaft and meshes 
with a worm gear N. The latter turns as a stationary nut for 
screw S, which causes screw S to push against the lower corner of 
the bell-crank lever L. 


168. A Typical Arrangement. — Fig. 52 shows a typical arrange- 
ment of weights and levers for controlling the pressure of an 
upper couch roll, or an upper press roll, on the paper and on the 
lower roll. The hanger is made in four parts, the top part hook- 
ing into the swinging arm at H, Fig. 51(6), that carries the top roll; 
in Fig. 52, this part is simplj^ an eye bolt B. The second part is 
the turn buckle T, which is used to adjust the length of the 
hanger. The third part H completes the turn buckle. The 
fourth part £' is a long eye bolt that carries lever L, which presses 
with its short end under the flange of the press frame, as shown 
in view (6) ; it is hung, and pulls down on the center of the hanger 
E at P, holding hanger F on its long end. Hanger F is a tee-(T) 
headed bolt, the tee head resting on the long end of lever L. 
The nut on the bottom end of F holds in place a wedge-shaped 
washer casting C, on which rests the lever G, the hanger F passing 
through the lever. The short end of lever G turns on pin M as a 
fulcrum, and on the long end, the necessary weights are placed, 
as shown at W. 




169. Pressure Produced by the Weight.— If the weight W, 
Fig. 52, be so placed that the distance di from the center of 
gravity of the weight to the center of the pin Af is 8 times the 
distance di between the center of the wedge-shaped casting C 
and the center of the pin M, then the resultant pull downwards 
on hanger F is 8 times the weight W. If W weighs 50 pounds, 
the downward pull (pi) on /^ is 8 X 50 = 400 pounds; this is 
























Ca) Cb) 

Fig. 52. 

exerted on the end of lever L, the length of whose power arm is 
indicated by di, and the length of whose weight arm is indicated 
by di. Suppose these lengths are carefully measured, and it is 
found that d^ =3 X ^4; then the resultant pull (7)2) on E is 3 
times the pull on F, or 400 X 3 = 1200 pounds, which is exerted 
downwards on the swinging arm that holds the upper roll. The 
arrangement is evidently a compound lever, in which the power 
arms are represented by di and di, and the weight arms by di and 
di. Since di -r- d^ = 8, and di ^ di = ^, the velocity ratio of 
the combination (its mechanical advantage) is 8 X 3 = 24. 
Therefore, the pull on E is 50 X 24 = 1200 pounds, the same 
result as before. 


In the housing shown in Fig. 51(6), the ratio of the lengths of 
power arm d^ and the weight (pressure) arm d^ is dr,: de = 13:9, 
Therefore, the total theoretical pressure exerted at the line of 
contact of rolls K and Ki by the weight TT is 50 X 8 X 3 X V- 
= 1733^ pounds. The velocity ratio of the entire combina- 
tion is 8 X 3 X '/ = 34f . Since there is a similar combination 
on either end of this roll, a pressure of at least 1700 X 2 = 3400 
pounds will be obtained on the nip between the rolls by hanging 
a weight of 50 pounds on the levers G, Fig. 52, in the position 
shown; and to this must be added the weight of the top roll. 
It is, however, the weight per inch width of press roll that counts 
in pressing the paper. 

170. Press-Roll Details. — When a machine is exceptionally 
wide, the top press roll is exceptionally heavy; and it is well to 
remember that it is not good practice to subject the rubber 
covering of the press roll to a pressure of more than 50 pounds per 
lineal inch of face, more especially, if the rubber covering be 
soft. This pressure is often largely exceeded to the detriment of 
the rubber covering. The machine tender should add only 
weight enough to cause the top and bottom rolls to meet at 
every point across the line of contact. 

Rubber covers on lower press rolls were used at first, instead of 
wood and brass coverings, for two reasons: one reason was to 
save the felt; the other reason was to obtain a compressible roll, 
to compensate for insufficient crowning. The weights (W, Fig. 
52) are used for obtaining the necessary compression of the roll 
surface, to close all gaps between the press rolls. On narrow 
machines, a softer rubber covering can be used than on wide 
machines; and the use of levers and weights on the press arms 
is more practical for the correction of the small errors in crowning 
that may occur on machines up to, say, 120-inch face of rolls. 
On wide machines, a closer approximation to the correct crown, 
when the bottom roll is first crowned, permits the use of a 
stiff er rubber covering and a less extensive use of levers and 
weights. Wide machines have very heavy upper press rolls; 
indeed, it is hard to design them so they will not exceed 50 pounds 
weight per inch of face. 

Many machine tenders, when coming on their shift, alter the 
position of the weights on either the couch roll or the press roll, 
because every man has his own ideas regarding this; but the 
pressure should always be as light as possible on a wide machine. 


If a press roll be not ground accuratelj-, and is larger in diameter 
at one end than at the other, the paper will be dryer at the larger 
end, if the same weights are used. 

Sometimes the steam in the dryers is not properly controlled, 
and one side, sometimes the side on the front of the machine, 
may be colder than the other side; so the machine tender tries to 
correct the lack of uniformity of drying by changing the weights 
on the upper press rolls; but this is poor practice. 

Press rolls should be carefully calipered with micrometer 
calipers, the diameters being taken for every 6 inches of their 
length. A record should be kept of these measurements; and if 
the record be plotted, it will show the shape of the roll and be a 
useful guide to re-grinding. The plot is made by making an 
outline of the roll and indicating the diameters at the proper 
distances across it. The plot shows the diameter as measured at 
the distance indicated from the end of the roll. 


171. Why the Doctor Is not Stationary. — As previously 
mentioned, the doctor is used to scrape off and collect the wet 
broke from the top press roll and to collect particles adhering to 
the roll. If the doctor were to remain fixed in position while 
scraping, it would soon reproduce its own inequalities on the shell 
of the press roll, its edge scratching and scarring the surface. To 
prevent this, doctors are provided with an auxiliary mechanism 
that causes them to vibrate to and fro, and this motion results in 
a smoothing action between the edge of a doctor and the surface 
of the roll. The period of alternation (vibration) should not be 
an exact divisor of the time of one revolution of the roll; for 
instance, let a = number of vibrations per minute, and h = revo- 
lutions per minute of roll, then the quotient obtained by dividing 
6 by a must not be an integer (whole number) ; otherwise, the 
same inequalities will come together at regular intervals. By 
giving proper attention to this detail, the roll surface and the 
doctor edge will remain smooth. 

172. Description of Vibrating Mechanism.- — The mechanism 
for vibrating the doctor is shown in Fig. 53. A worm casting W 
is fastened to the press-roll journal by set screws; it meshes with 
the worm wheel IFi, which is keyed to shaft S. As the top 
press roll turns, worm 11^ turns with it, and this causes worm wheel 




Wi and shaft S to turn also, but very slowl}- compared with the 
speed of the roll. One end of lever L is fastened to the top of 
shaft S bj' a tap bolt Ti, the center line of which is eccentric to 
the center line of the shaft S; hence, the center line of Ti revolves 
around the axis of the shaft when the shaft S turns, and this 
causes the end of lever L to turn around the same axis. This 

Fig. 53. 

movement compels the other end of the lever, which is fastened 
by tap bolt T2 to doctor D, to move to and fro a short distance in 
a direction that is across the machine, and thus gives the doctor a 
vibrating motion. The position of the doctor blade with refer- 
ence to the top of the roll is adjusted by means of screw V; there 
are two such screws, one at either end of the doctor. The 
doctor blade may be made of steel, brass, hard rubber, or vulcan- 
ite; the latter two substances have less wearing action on the roll, 
and they do not rust or corrode. 



173. Lining Up the Suction Rolls. — Mention may here be made 
of the suction press rolls, which are now often used on the first 
press and sometimes on the second press. The mechanical 
operation of the suction press roll is much the same as that of the 
suction couch roll, and the same degree of care must be exercised, 
when installing one, to get the suction roll lined up with the rest 
of the machine. In this case, however, the upper roll is not 

The position of the suction box inside of the suction roll requires 
very careful adjustment. On account of varying conditions, it 
may be necessary to try the suction box in several positions 
before the correct one is definitely determined. Some experi- 
menting may also be required in connection with the kind of 
felts used, it having been found that what works well in one mill 
is not always best suited to conditions in another mill. It is 
recommended that the felts used on a suction press roll never be 
turned over; hence, such felts need be napped on one side onl}^ 
When running on a suction press roll, felts should last very much 
longer than when running over the old-style press rolls. 

174. Construction and Operation. — The top roll may be of 
wood or it may be rubber covered or of granite, depending on the 
character of the paper being made. When given the proper 
crown, a wood roll works very well in most cases. The face of 
the suction press roll is straight, and all crowning that is necessary 
must be given to the top roll, the function of which is to smooth the 
surface of the paper. If wet streaks appear in the sheet as it 
leaves the suction press, it is certain that the top press roll is either 
unevenly weighted or is incorrectly crowned. The top roll should 
not be weighted any more than is absolutely necessary, since the 
suction of the bottom roll does most of the de-watering. This 
latter feature accounts for the ability to make a bulkier sheet over 
suction rolls. As it leaves the suction press roll, the sheet should 
be carried up over a draw roll of small diameter; if left on the felt, 
the sheet will have a tendency to absorb moisture from the felt. 

175. As fast as any water is pressed out by the top roll, it is 
immediately carried away by the bottom suction roll; this 
eliminates the usual pond of water that collects at the nip of 
plain press rolls, which is caused by the up-coming surface of the 
plain bottom roll constantly carrying the pressed-out water back 






into the nip of the rolls. This action further eliminates blowing, 

crushing, felt marking, and such 

kindred troubles as are caused by the 

objectionable pond of water that is 

always seen at the nip of plain press 


Large volumes of air are constanth^ 
being drawn through the felt and into 
the suction roll; this action tends to 
keep the felt open and clean, so that 
less frequent washing is required. On 
machines making krafts and manilas, 
for instance, no felt washing is done, 
except at the time of the regular 
weekly shut down. 

The suction press largely prevents 
first-press breaks, irrespective of the 
condition of the stock and of the speed 
of the machine. The atmospheric 
pressure holds the sheet down on the 
felt, while it passes over the suction 
area, with a force sufficient to over- 
come its natural tendency to stick and 
follow up on the top roll. 


176. Description of Felt Suction 
Box. — Felt suction boxes are similar 
in design to the wire suction boxes, 
except that no arrangement is made 
for reducing the suction area when a 
box without cover is used; that is, the 
rubber piston and the adjustments for 
it are omitted. The felt suction box 
shown in Fig, 54 is made from a pipe 
P, on top of which is a trough A for 
the purpose of keeping the felt F from 
actual contact with the pipe and 
closing the holes H, which are 2 
inches in diameter. As the felt passes 

-i d 



over the trough, the suction tends to draw the felt down into 
the trough, up to the holes H. Since the felt is being stretched 
tight as it moves, the force of the suction simply draws 
the felt down, as indicated bj^ the dotted hne in the end view, 
just enough to make the contact between the felt and the edges 
of the trough sufficiently air-tight and water-tight to allow the 
strip between the edges of the trough to have a part of its con- 
tained water sucked out and drawn into the pipe P. The suction 
box is drained at >S. A perforated wood top similar to the type 
used on the wire is preferred b}- many, who claim this type is less 
wearing on the felt. 

177. Operation. — There is no particular need for altering the 
width of the suction area of a felt suction box; because the felt is 
always wet, whatever the width of the paper being made, and a 
felt suction box is used to dry the felt. However, the limiting of 
the length of the active suction area to the width of the paper will 
give a better vacuum. 

Felt suction boxes are generally placed below the felts, just 
before they enter the nip of the first and the second presses. If 
the felt be kept as dry as possible, the presses are helped in their 
work of pressing the water out of the paper into the felt that 
carries the paper between the presses. The edges and tops of 
felt suction boxes must be kept as smooth as possible, to guard 
against damaging the felt as it passes over the box and is dragged 
into it by the suction. 

Felt suction boxes are built in many ways; a pipe suction box is 
here described, not because it is superior to other designs, but 
because it illustrates better the principal features of a good suction 
box. The use of a perforated cover, similar to that on a wire 
suction box, is allowable, provided there is a smooth surface 
and no sharp edges that will wear the nap off the felt. Such a 
cover is made of wood, with diagonal slots, which overlap enough 
to provide a drj-ing action over the whole width of the felt. 

It must not be forgotten that the suction box acts also like a 
brake on the felt, and that a heavy suction must necessarily 
shorten the life of the felt. 


178. A Typical Design. — In Fig. 55 is shown a typical design 
of a hand-operated stretcher for a press felt. The press-felt 
roll R, which carries the half lap of felt, is supported by journals 




that turn in the brackets F; and a screw thread T, Fig. 56, in 
each portion of the brackets fits inside the brass pipes P and Pi. 



n 1 

■/ir": 1 if 









Brass Pipe 


Fig 55. 

In both pipes, there is a slot throughout nearly its whole length, 

to allow the brackets to slide along the outside of the pipes and 

also to project inside, so as to 

engage the threaded shaft T\ that 

runs inside of the pipe. Fig. 56, 

which is an enlarged sectional view, 

shows this detail more clearly. The 

screw T\ can turn, but cannot move 

otherwise. The screws have bevel 

(miter) gears G at one end, the gears 

meshing with them being on shaft <S. 

By turning hand wheel IF, shaft S 

and the miter gears revolve; this 

causes the screws in the pipes on 

either side of the machine to turn 

equally until the brackets carrying 

the felt roll are in the correct 

position to keep the felt in the state of tension required. Fig. 55 

shows the stretcher furnished with a bracket B on one end of 


Section on X-X Fig. oj (Enlargerl) 
Fig. 56. 







each pipe, to bolt to the side of a housing 
or upright casting, and a bracket C on the 
other end, to bolt to the press frame. 

179. Velocity Ratio of Stretcher.— This 
stretcher gives the machine tender a 
velocity ratio of several hundred to one, 
according to the pitch of the screw and the 
other dimensions. Fortunately, the efl&- 
ciency of such a piece of machinery is not 
over 25%; otherwise the felts would be 
overstretched, more than they are now on 
many a machine. 

It is customary to have a cam arrange- 
ment that will throw out the gears on the 
front side, so the back end of the stretch 
roll can be operated forward or backward 
of the position of the front end, in order 
to make up for inequalities in the length 
of the felt. 


180. Felt Whippers.— The felt whipper, 
see Fig. 57, is designed with 2, 3, or 4 
blades A, which are bolted to spiders B. 
The blades are made almost always of 
wood, and the outer extremities are rounded 
to an arc of a circle, as shown. Brass pipes 
may be used instead of blades. The spiders 
B are mounted on a shaft S, which carries 
the driving pulley P. The whippers are 
placed on the outside of the felt; they 
revolve at about 125 r.p.m., and in a direc- 
tion such that the edge of the blades will 
not knock the nap off the felt. The rapid 
motion of the whipper causes the felt to 
vibrate forcibly against its blades, which 
beat out the dirt from the felt. A strong 
shower (Ji and J2, Fig. 50) is directed 
against the inside of the felt, to wash out 
the loosened dirt. The shower is generally 
placed after the whipper (in the direction 




in which the felt is traveUng), though some designers prefer to 
place it before the whipper, as shown in Fig. 50. The pulley P 
is belt driven from the nearest conv^enient driving shaft of the 
machine. Care should be taken so to adjust the position of the 
whipper that the blades will not scrub against the felt, thus 
wearing out the felt; it should beat the felt with quick, sharp 
blows, which do not tend to scrape off the nap. P'elt whippers 
are almost always omitted on fast machines. 

181. Showers. — There are several patented attachments for 
washing felts without stopping the machine; for the most part, 
these consist of a shower to distribute warm water, soap, or a 
chemical solution, and a suction box to draw out the dirty water 
and loosened dirt. On some machines, a pair of squeeze rolls are 
used to remove the water used for washing the felt. 

Some experiments have been made in connection with the use 
of a steam jet instead of a shower; but the higher temperature is 
apt to shorten the life of the felt. 


182. Auto-Swing Guide Rolls. — Fig. 58 shows the guide roll 
G\, Fig. 50, in greater detail. The bearing of one journal of the 

SMng or 
Strip oFFelf 

Fig. 58. 

guide roll R is hung at P from a pivot on the tending side of the 
machine. The bearing of the other journal is carried in a 
bracket B, which is moved by an adjustable hand screw S. 
When the hand wheel W on the end of this screw is turned, the 
bracket carrying the guide roll is caused to move by means of 
the screw thread that is tapped in the bracket, and in which the 
band screw turns. The position of the roll is so adjusted by this 


means that the felt has a slight tendency to come to the front 
(tending) side of the machine. 

The front journal, whose bearing is in the swinging arm A, is 
connected by a string or strip of felt to a cylindrical wooden block 
that fits loosely on the end of an adjacent felt roll (as F5, Fa, Fig. 
50). When the felt travels to the front side of the machine, it 
climbs onto this wooden block and turns it; this causes the 
string to wind up on the block and pulls the guide roll toward 
the block, thus correcting the travel of the felt. The principle 
is the same as that explained in connection with the wire guide 
roll. Fig. 58 shows the arrangement in perspective. It is 
customary so to hang the front end of the guide roll that the felt 
will be guided forwards again when the felt has left the block 
after the travel has been corrected. When the felt has left the 
block, a counterweight draws the string back to its former 

183. Paper Rolls. — Since the paper is weak when wet, it is 
important that the rolls over which the paper travels shall turn 
very easily; for this purpose, the bearings must be well lubri- 
cated. Ball bearings are a distinct advantage here. An English 
invention provides for driving the bearing, the friction driving the 
roll, when idle, a little faster than the paper speed. 



184. Taking Off the Old Felt— The method of putting on a 
new felt will now be described. The old felt is cut across the 
machine and rolled up by hand, the press part being run slowly. 
If the old felt is to be used again, as is sometimes the case with 
a wet or first-press felt that is considered good enough to use 
as a second-press felt, or if it is to be washed, the old felt is 
taken out as follows: Clean the ends of press rolls, bearings, etc., 
thoroughly; slack up on stretch roll; raise upper press roll by 
means of the housing (lever), and pull out the old felt from 
between the rolls; lay the felt over the upper-roll bearing; lower 
front end of upper roll, and slip 5'oke or loop over the journals 
of the upper and lower rolls; raise again on the lever, which will 
lift lower journal from its bearing and permit the removal of the 




Top Press 
She/ Link 

'Boffom PreS'S. 

pedestal; take out lower side of old felt; the pedestal is now 
replaced and the rolls lowered. The felt is now outside the press 
rolls, and it may be removed by lifting the ends of the felt rolls 
and slipping the felt over them. 

185. Putting On a New Felt. — All grease and dirt must now be 
thoroughly removed from the frame and from the front ends of 
the rolls, and from any place the felt may touch; the trough under 
the roll is removed. The new felt should be laid out full length, 
preferably on the foot bridge across the machine or on the clean 
tending floor, with the nap of the felt lying down with the run 
of the paper. The felt is not laid 
out full width, but is doubled on 
itself in folds until its width is 
reduced as much as possible. It 
is a good plan to lay out and 
arrange the felt on the clean floor 
of the felt room. Don't walk on 
it. The top press roll is then 
raised by the housing, and the 
felt is placed between the journals 
of the two press rolls, with the 
nap so it will lie down when the 
felt is running, the cap on the 
lower roll being removed, and the 
journal and bearing wiped clean, 
until the steel hnk is in place over the two press journals. The 
hnk is inside of the felt, as shown in Fig. 59. When the link is in 
position, the top press is again raised by means of the mechanism 
already described; this raises the lower roll also. The bracket 
and bearings under the lower roll are then removed, and the 
frame and journal are wiped clean. 

The felt is then passed over the end of the lower roll, and the 
bearing is carefully replaced. The rolls are lowered, the journal 
of the link is removed, and the top roll is raised until the felt 
can be spread out between the rolls. The felt is then pulled out 
lengthwise, so that it extends, while still as narrow in width as 
possible, along the inside of the machine in the path in which it is 
to travel. When a machine tender reaches a felt roll, as he is 
pulling out the felt along the machine, he lifts the roll out of its 
bearing and puts the felt over the end of the roll; and this is 
done with all the felt rolls that run inside the felt, if the felt is 

The top press is then lowered 


long enough. If necessary, the stretch (or hitch) roll is taken 
out and put in last. 

The felt is now in its proper place, but it is all rumpled up. 
It can be edged across the machine gradually by running the 
press part slowly, with the top roll down just enough to catch 
the felt and pulling the felt across, using the guide roll to help in 
doing this. While it may take longer, the felt will last longer 
than when it is pulled and hauled across the width of the machine 
by main force. Give the felt time to adjust itself, without 
trying to increase production by gaining a few minutes at the 
expense of the felt. 

186. Wetting the Felt. — When the felt is across the machine 
and the stretch roll is in place at its shortest stretch, the upper 
roll is lowered and the felt is wetted. The wetting should not 
be done with a hose, because it is very easy to spoil a new felt 
by getting too much water in one place; a buckle caused by such 
action cannot be removed. A shower pipe across the machine 
should be used to wet the new felt gradually, care being taken 
that the felt is not moving until a steady, even stream of water is 
flowing over one roll across the full width of the felt. 

The foregoing description of the method of replacing a felt is 
applicable to all felts on press parts. On a cylinder or Harper 
machine, there is more than one pair of presses, but the method of 
placing the felt over the press rolls is practically the same in all cases. 

187. Felt Marks. — Felt marks are the principal cause of 
many troubles that develop at the press part of the paper 
machine. The phrase "felt mark on the paper" is usually a 
misnomer; it is the impression made by the threads of the felt 
only in the case of old or too coarse felts, but is generally applied 
to the defects in the paper caused by the gradual filling in of spots 
in the felts meshes, which make the felt harder; the final result 
is the accumulation of stock and filler, which destroys the ability 
of the felt to press water from the paper, and a blotch is formed. 
The water can escape when pressed out from the paper only by 
passing through the felt meshes at the side of these spots. The 
only remedy for this trouble is to clean the felt. When the 
felt is new, and if the lower rubber-covered roll be not too hard, 
a new felt should run satisfactorily for 48 hours without washing; 
but, as the felt ages, the time between washings is reduced, and 
felt^ finally have to be cleaned every 24 hours. 


188. Washing the Felt. — The felts are washed on the machine 
as follows: 

Remove all weights and levers; then slack the felt by moving 
the stretch roll back as far as it will go. Turn a strong stream of 
clean water on the felt, and push the felt on itself, toward the 
center, until there is a clear space, about 2 feet wide, from both 
ends of the rolls. Allow the felt to run in the water this way 
until clean, or for about 45 minutes in the worst cases. When 
it is observed that the water that is being washed through the 
felt is coming away clear and clean, it indicates that the felt has 
been washed sufficiently. It may then be pulled flat by gradually 
drawing the edges to the front and back sides of the machine; 
keep the hands away from rolls, avoid danger. Before pulling 
out the felt, clear it of wrinkles; if it be a double-napped felt, 
turn it over, so the outside will be on the inside; this will insure 
that the felt wear uniformly on both sides; it will also give a 
longer running time between wash-ups, because the newly- 
washed, dirty side of the felt is now on the inside, and the water 
pressed from the paper that leaves the felt from this side will carry 
off all the fine particles in the felt that may have remained after the 
felt washing. A weak solution of soap or soda ash is sometimes 
poured on the felt to assist in the cleaning. (See also Art. 181.) 

189. Care and Life of Felts. — A felt that is properly cared for 
should give 3 or 4 weeks of service on a fast news machine, which 
is very hard on felts, because of its high speed and the quality 
of the stock. On the slower running book machines, there is no 
reason why a felt should not last much longer. The elimination 
of rolls running on the outside of the felt lengthens the life of the 
felt. Such rolls gather particles of^fiber, forming lumps that 
dirty the felt. 

With good, smooth, brass-covered felt rolls of proper stiffness, 
with the upper press roll kept in good, smooth order, with the 
rubber-covered roll not too hard, and with the right amount of 
crown, the machine tender who exercises common sense regarding 
the amount of tension he puts on the felt at the stretch roll, may 
solve all the mysteries of how to get the longest wear, the longest 
run between wash-ups, together with a minimum of breaks and 
felt marks. 

190. General Rules for Washing Felts. — At this point, it is 
advisable to give some instructions regarding the proper washing 


of felts. Cases are known where a felt has been run in the washer 
for nearly a full day; such treatment, of course, practically ruins 
the felt. The following are general instructions for the proper 
washing of felts when the washing is done off the machine: 

The temperature of the water should not exceed 120°F.; 
that is, it should not be hotter than one can comfortably bear 
when placing his hand in it, since a higher temperature injures 
the wool fibers. 

The quantity of soap to be used varies with the amount of dirt 
to be removed from the felt, and with the amount of size that 
has been used on the paper; however, enough soap should be 
used to give a good lather. 

Use a good neutral soap that rinses out readily, and do not use 
strong alkalis, because alkalis containing caustic will dissolve 
wool fibers. There are brands of soap that have been specially 
prepared for this purpose, and one of these should be employed; 
the ordinary soap used about the mill is not satisfactory for 
felt-washing purposes. 

If felts are washed in warm water, it is much better to reduce 
the temperature of the water gradually, while the felts are being 
rinsed, until the natural temperature of the water is reached; sud- 
den changes in temperature change the original texture of the felt. 

The felt should not be run in soap more than 20 minutes, and it 
should be rinsed only long enough to wash out the soap, say 
another 20 minutes. If a new soap is bought, try it out on a test 
strip of felt. Never use free acid on a felt. 

191. Preservation of Felts and Jackets. — During the Great 
War, the United States Government studied the question of 
conservation of essential industrial materials. The following 
recommendations made with regard to felts are worthy of careful 
study : 

Watch the stock carefully, and keep it in a cool, absolutely dry 
place — moisture causes mildew and destruction of wool fibers. 
Felts and jackets should, if possible, be kept in their original 
papers, tied tightly; and see that there are no holes in the papers. 
Keep the felts clean; dirt injures them and attracts moths. 
Keep the whole felt room clean and in good order. 

Use moth preventives freely and frequently; strong tar paper 
is good for this purpose, and the shelves should be covered with 
it. Flake naphthalene is the best preventive, but it evaporates 
and must be renewed. Sprinkle the felts thoroughly with the 


naphthalene and scatter it around the felt room. Examine 
the stock at least once a month for traces of moths or for other 
injury. Use the oldest felts first. 

Handle the felts with care when taking them to the machine. 
Felts are bulky and heavy, and they may be torn by catching 
on a nail or anything sharp; put them down only in clean places. 
Clean all journals and bearings before putting on felts, to keep 
the felts free from grease. 

Above ever3^thing else, the life of a felt depends on the con- 
dition of the machine. See that all press rolls are turned with 
the proper crown to assure the very best running conditions; 
press or felt rolls that are in bad condition, rough suction-box 
covers and whippers, and badly made spread rolls, often reduce 
length of service 50%, or even 75%. 

See that every roll turns freely; cylinder bearings should be 
carefully w^atched. All felts are subjected to great strains 
lengthwise, cylinder felts especially. Don't stretch the felts too 
tight. A large percentage of felts are ruined by running under 
unnecessary strain. 

Felts on idle machines deteriorate almost as fast as when 
running. When shutting down, raise the top press roll; see that 
the felt does not come into contact with iron, as rust quickly fills 
the pores; see that the air can reach it at every point, so it can dry 
quickly and thus prevent mildewing. 

Use care in handling jackets; they are tough and strong, but 
that is no reason for rough treatment. Be careful in stretching, 
shrinking, and tying down (lacing); watch the condition of the 
guard boards; above all, don't set guard boards down tighter 
than is necessary. Don't take off felts before they are worn out; 
get all possible wear out of them, even at some risk of a shut- 
down during the week. Superintendents and foremen should 
examine felts on machines before allowing them to be taken off 
and new ones given out. Don't make blankets from felts that 
can be run longer; by observing this one precaution alone, some 
mills have increased the life of their felts by weeks. 

Carefully wash and dry all used felts, and keep them as clean 
as possible; their value depends on their condition. Don't 
destroy even small pieces of worn-out felts; every pound can be 
used for some purpose. 

For reasons of economy and good business management, 
superintendents, foremen, and machine tenders will observe 




all the foregoing precautions and many more that will occur to 
them in practice. In the long run, greater production will be 
obtained by not being careless about the condition of machines 
or in the use of felts and jackets. Take time to put everything 
in first-class condition; the time thus spent will soon be made up. 

192. Tension of Felts. — While it is very important to consider 
the tension of the felt, it is equally important that the seam be 
kept straight across the felt. The seam will run ahead on the 
ends or at the center, according to the condition of the rolls and 

Square Openings 
in Mesh 

Dicumond Shape 
Openings in Mesh 

Fig. 60. 

the amount of crown used. When the crown is excessive, the 
seam will run ahead at the center. When the felt is unequally 
stressed in this manner, the meshes are partially closed, due to 
the diamond shape that they are thereby forced to assume; 
this effect is illustrated in Fig. 60. The left-hand part of the 
figure shows the meshes (greatly exaggerated) when the felt is 
running properly, while right-hand part shows the meshes 
when distorted by excessive crowning, or by having one side 
run ahead of the other. 

When first put on, a felt can run under much less tension than 
later, and distortion of the weave has less effect, because the felt 
has enough nap to offset the extra pressure of the rolls. Further, 
under these conditions, the tension is not severe on the felt, and 
it would not then be absolutely necessary to correct for a crooked 
seam; in fact, the remedy might be worse than the disease, the felt 
being caused to widen excessively and to run against th« frames. 




193. Influence of Tension on "Width of Felts. — The extra 
width on new felts must not be trimmed off when they are new; 
it will be needed later, when the felts become thin with wear. 
They should be ordered of correct width. When it has become 
worn, it is obligatory to increase the tension on a felt, in order 
to open the meshes and thus more readily release the water. 
The width of a felt is controlled to a certain extent by its tension : 
when the tension is great, the felt naturally narrows, and it 
spreads when the tension is relieved. 

194. Widening Felts.— When a felt has been narrowed by being 
stretched under the tension, it can be widened again by slacking 
the stretch roll and making one of the inside rolls (around which 

Fig. 61. 

the felt wraps more than a quarter of a circle) into a worm. 
This latter operation is effected as shown in Fig. 61, by tacking a 
strip of felt to a wooden roll, or by fastening a brass strip to the 
roll either by means of countersunk screws or by solderng it to 
a brass roll. Examination of Fig. 61 shows that the worm is 
double threaded and that it has right- and left-hand threads, 
the part to the right of A being left-handed and the part to the 
left of A being right-handed. As the felt moves in the direction 
of the arrow, the friction between it and the roll causes the roll to 
turn also, and the threads tend to push the fibers away from the 
center A, which widens the felt. 

A simple felt spreader may be constructed of two light wood 
rolls, which are a little more than one-half the length of the felt 
rolls; these are supported under the felt, with their axes making 
a large angle with each other (say 160°), like a shallow V, the 
apex of which points to and meets the center line of the 
oncoming felt. These rolls, of course, are dropped or otherwise 
taken out of contact with the felt, when it has been widened 

195. Guiding the Felt. — To guide a felt, the end of the guide 
roll must be moved in the direction in which the felt is running, 
if it be desired to make it travel away from that end; but if the 


end of the roll be moved against the run of the felt, the felt will 
travel toward the end that was moved. 

If the seam, or blue line, of a felt be not parallel with the axis 
of a felt roll, i.e., if one end be ahead of the other, the end ahead 
can be brought back by increasing the stretch on whichever end 
of the hne is ahead. The felt should be watched carefully when- 
ever a roll is shifted, to see that its position is not altered. In 
cases where both ends of the seam are even (parallel with the axis 
of a felt roll) and the center is drawn back, add extra worming 
in the center of the roll, or at any place where the felt lags back. 
Another remedy is to wind cotton twine (or a strip of paper 
having a little paste on the ends) around the roll, in line with the 
lag places ; but care must be taken not to wind too much on the roll, 
since it is much easier to add a little more than it is to take some 
off. This winding is removed, of course, when the fault has 
been corrected. 

196. Wrinkles and Slack Places. — In cases where a straight 
wrinkle or lap appears in a new felt, and this often happens on 
wide machines (where the rolls are inclined to spring), run the 
felt slack and keep the wrinkle from running through the press 
by constantly pulling on the felt. But take care not to get 
caught in the rolls! Slack up the tail and tighten up the head 
of the wrinkle, by moving the guide roll or stretch roll. Hot 
sizing poured on the wrinkle will make it disappear almost 
instantly, if the sizing be not allowed to go through the press 

Another trouble is the result of slack places and thin streaks or 
spots, which are due to excessive wear at certain points; these 
are frequently caused by accumulations of paper stock on a felt 
roll, which stretch the felt in spots the length of the felt, and the 
felt whipper wears these places thin. 

197. Analogy between Felts and Belts. — It is readily perceived 
that the felt acts like a belt, and it drives many rolls that would 
be undriven otherwise; these rolls all act as brakes, and to their 
action must be added the braking action of suction boxes. It 
is also evident that the place of greatest stress and strain is close 
to the driver, where the sum of all the hold-backs is concentrated. 
This naturally brings up for consideration the matter of type 
of bearings and the kind of lubrication used on journals of main 
press rolls and of the felt rolls driven by the felt. 


198. Lubricating and Cooling Journals. — The journals of press 
and couch rolls (unless ball bearing) are water cooled. The cast- 
ings that hold the bearing metal are hollow, and cold water is 
circulated through them. 

Many methods of lubricating paper-machine bearings are in 
use, ranging from the open-top bearing, with a piece of ham fat 
resting on the revolving journal, to the more pretentious bearings, 
which have a continuous supply of oil from a pump that may get 
out of order or from a reservoir that needs filling. Capillary bear- 
ings, which depend on a lamp wick to draw oil from a reservoir 
and w^ipe it on the journal, are also used with good results. 

Paper-machine journals run at comparatively slow speeds; 
they should be amply large for the weights they support, and 
should have a cover over them, to keep out dirt and water and 
to keep in the oil or grease. A good millwright can often cure a 
bearing that gives trouble by cutting two helical grooves, say ^V 
inch deep, on the journal, so as to compel the oil or grease to run 
around the journals until it reaches the place where the weight is 
carried. If the millwright is sufficiently experienced, he can tell 
where these grooves ought to be by examining the journals after 
they have begun to give trouble. Felt-roll bearings should 
have self-alining bronze bushings to line up with journals which 
are frequently bent. 

199. While on the subject of bearings, it may be remarked 
that unless the paper machine is kept running all the time, and is 
making paper all the time, it is not making money. The cost of 
power to run it is but a drop in the bucket w'hen compared with 
the value of the production lost through the shut-down of the 
machine for an hour or so a day; therefore, keep the bearings 
cool. A water-cooled bearing is simple and practicable. 

200. Length of Felts and Number of Rolls. — Many mill men 
think a long felt is better than a short one; but, in most cases, 
this is far from being true. If additional rolls accompany the 
longer felt, there is no gain. For instance, a 45-foot felt running 
around 9 rolls is no better than a 35-foot felt running around 7 
rolls; in fact, it is much worse, on account of the extra hold 
back of the two additional rolls, which evidently increases the 
total stress very near the driver. The life of a felt is materially 
increased by reducing the number of rolls that come in contact 
with the outside of the felt. 


201. Pick-Up Felts. — If it is desired to have a felt pick up and 
carry away paper from another felt or from a wire, a smooth- 
surfaced felt that is air- and water-tight is needed. Such a felt 
must be woven of fine wool, and it should be napless; otherwise, 
it must be singed or sheared. A pick-up felt must be air-tight; 
therefore, it may be well filled with sizing. Trouble may often 
be experienced with a new pick-up felt; when this occurs, fill up 
the felt with sizing, which is poured on until the pores are filled, 
and the pick-up felt will then do its duty. 

Owing to the attention now giv^en by felt manufacturers to the 
requirements of paper manufacturers, and their mutual coopera- 
tion, the paper maker need onlj^ give the size of his felt and the 
quality of the product he is making. 

202. Weight of Felts.— As to the weight of felts for different 
qualities of paper, there is very little information that can be 
accepted as a standard, because of the different ideas of various 
manufacturers of felts and paper. For instance, the weight of 
felts made by one manufacturer for a certain purpose might be 
quite different from the weight of felt made by another manu- 
facturer for identically the same purpose. One manufacturer 
of felts for news gets the best results from felts weighing 2 ounces 
per square foot; another manufacturer could not make a felt of 
this weight do the work satisfactorily, and had to make the 
weight of his felts 2.25 to 2.50 ounces per square foot. Similarly, 
for third-press felts for news, some manufacturers get the best 
results from felts that weigh 2.5 to 2.6 ounces per square foot, 
while others make their third-press felts weight 3 ounces or 
more per square foot. It is a question of durability and openness; 
given the same strength and durability, the lighter felt is more 
open and will give better results. 

203. Qualities of Felts. — The first, second, and third felts for 
news and wrapping papers should have qualities about as follows, 
to obtain the best results: 

First Felt. — The first felt should be of plain weave, made 
open, well napped, weight about 2 ounces per square foot, and 
should be wo^'en endless — not made endless by hand, as has been 
common practice. 

Second Felt. — The second felt should be the same as the 
first felt, except it should be somewhat heavier; weave like the 
first felt, but weight should be 2.25 ounces per square foot; this 


felt should also be woven endless. After use on the first press, 
the first felt is sometimes used as a second felt; but if the nap is 
well worn, the paper may be marked. 

Third Felt. — For the third felt, a fine twill-weave press felt 
should be used; weight should be 2.75 ounces per square foot; it 
should be well napped. 

204. The Function of the Felt. '— When a felt and sheet of 
paper pass between rolls, the following conditions exist as shown 
in this diagram. Felt A and the wet sheet of paper B pass 
between the rolls M and N. As particular points, a and a' 
adjoining on sheet and felt, move into the nip of the rolls, a 
position b and h' is reached where water will begin to be squeezed 

out of the paper and felt. From this point on, the pressure 
becomes more and more concentrated, felt and sheet are com- 
pressed closer together and water is released from both until 
c and c' is reached where the two rolls approach the closest to 
each other and the greatest concentration of pressure is obtained. 
It will be noted, then, that felt and sheet pass progressively- 
through rapidly changing pressure, and that the condition of 
equilibrium of this system under a gradient of pressure dis- 
tribution will be determined b}'^ the relations of many different 
factors such as — 

I. The pressure apphed. 

II. Hardness of rolls. 
III. Radii of rolls. 

IV. The speed of the sheet and felt. 
'■ [Y. The time of contact. 
j^VI. The resistance of the felt to the flow of water. 

It will be seen in this diagram that the water passes from the 

sheet into the felt and through the felts throughout a gradient 

of pressure change. The ease with which water will flow through 

the felt at these different pressures is a very important factor in 

determining its efficiency as a water-remover. The openness or 

1 From an article, illustrated by charts, by E. A. Rees, in Pulp and Paper 
Magazine of Canada, Feb. 1, 1923. 


porosity of the felt has always been recognized as a desirable 
property of the felt. And the resistance of the felt to the flow 
of water is important in determining not only the dryness of 
the sheet but also other effects that have to do with ease of 
operation, such as crushing and blowing. 

It will be noted, however, that there are some discrepancies, 
as illustrated by several points that do not fall exactly on the 
line. The softness of the fabric also affects the concentration of 
the pressure upon the sheet of paper. Large variations in this 
property may so materially affect the concentration of pressure 
as to over-balance the porosity effect in different directions. 
For example, a hard, close felt might give a drj'^er sheet of paper 
than a soft, open felt, if the concentration of pressure is large 
enough to off-set the difference in porosity. 

It is also quite interesting to note that as the sheet and felt 
approach closer to points c and c', where the rolls are in closer 
contact, there is more and more resistance to the flow of water, 
because of the impervious roll beneath; and there is also the 
tendency for the revolving roll to carry the water back into the 
nip. As the water is released farther back in the nip, then, there, 
is more and more necessity for water to permeate through the 
felt in the direction contrary to its motion. This lateral or 
backward porosity through a gradient of pressure change is also 
a factor in determining the efficiency of the felt as a water- 

205. Felts for Particular Papers. — When manufacturing fine 
writings and bonds, the character of the stock is such that it is 
difficult to free it from water. Here finish is the goal; hence, 
the felts are of decidedly closer texture and are made of finer 
yarns than the common wet felts used for newsprint or wrapping 
papers. While a newsprint felt is of a plain weave, the felts for 
fine papers are generally of a complex weave, the nature of 
which is to cause it to act as a compact carrier and as a perfect 
filler. A fair estimate of the weights per square foot for this 
grade is 1.46 to 1.64 ounces. The second felt will be heavier 
and much closer, weighing from 1.56 to 2.68 ounces per square 
foot. The felt for the last press, if three are used, is very thick 
and it has a very heavy nap. It must be borne in mind that the 
felt must permit a perfect filtering of the water from the sheet; 
otherwise, the cost of production will be high on account of the 
excessive steam consumption for drying. 


The felt used on a machine making the general type of tissue 
papers is a plain-woven, rather close-mesh fabric, with little or no 
nap on the top side.- In fact, many mills prefer that a felt for 
making tissue paper be singed on both sides, to keep the fibers 
in the sheet from adhering to the felt surface (picking up). 
Singeing keeps the nap that is formed by the felting process from 
being drawn over the mesh of the felt by the suction box or roll. 
If the under side of the mesh is clogged by wool, the felt will soon 
fill up and get dirty, causing broke and many other difficulties. 

It is needless to state that the quality of the wool used in 
all these felts is a matter for the closest attention of the felt 


206. Construction of Press Rolls. — In the days when paper 
machines were so narrow that the attendant could almost reach 
across them, the lower press rolls were brass cased and the upper 
press rolls were made of wood. The nip, that is, the area of 
contact between the rolls, was very narrow, not only because 
of the absence of the resiliency and softness of the rubber cover- 
ing but also because of the small diameter of the rolls. A little 
thought will make it obvious that the area of contact between 
two rolls of large diameter will be greater than when the rolls 
are of small diameter. Now the quantity of water pressed out 
of the paper is directly proportional to the pressure per square 
inch of area of contact between the rolls; in other words, the 
efficient working of a press is measured by the specific pressure 
of the rolls (total pressure divided by the area of contact) and 
not by the total pressure. Pressure is frequently expressed as 
so many pounds per inch of width of the machine. 

The custom of covering the lower press rolls with rubber results 
from, first, the necessity for an automatic adjustment of the line of 
contact by an elastic medium, to correct for faulty crowning under 
differing conditions; also, second, to prolong the fife of the felt. 

207. Crowning the Roll. — Any beam will deflect (bend) more 
or less between its supports, because of its own weight; and the 
deflection will be increased by any other load that the beam may 
support. The amount of this deflection will depend upon the 
material of which the beam is made, the diameter of the beam 
(if round), and its length between supports. But there will be 
a certain amount of deflection always; and if the beam is straight 


and horizontal, it will sag in the middle under its own weight 
and under a uniform load across the beam. A roll in a paper 
machine acts like a beam, and its own weight plus the pull 
exerted uniformly across it by the felt cause it to sag in the 
middle. It follows, then, when two rolls are ground to true 
cj'lindrical surfaces and are placed one on top of the other, both 
being horizontal (or nearly so) and supported at their ends (their 
journals), they will not touch at their middle points. This 
condition is proved by the fact that light passes between the 
rolls; and it can be corrected by crowning the lower roll (which 
naturally sags the most) just enough to insure perfect contact 
from end to end. A roll is said to be crowned when it is larger 
in diameter at the middle than at the ends and gradually tapers 
from the middle to the ends. The greater the diameter of the 
roll in proportion to its length the stiffer it is, and the smaller is 
the amount of sag (deflection) ; therefore there is but little need 
of crowning, if the roll be large enough. 

But there are other considerations to be taken into account 
when choosing press rolls of large or small diameter for a paper 
machine. If the observer stand alongside a paper machine and 
note the escape of water at the nip of the press rolls, he will soon 
be impressed with the fact that the faster the machine runs the 
less chance the water has to escape, because the up-coming 
surface of the lower press roll continually tries to carry the water 
back into the nip; and the larger the diameter of the lower press 
roll the worse this condition becomes. Attempts have been 
made to place water deflectors close to the nip, to lead this 
water awaj^, and in this service they have been invariably suc- 
cessful. In practice, unfortunately, many accidents have 
occurred through their use, such as the deflectors getting into the 
nip, etc., with the consequence that these deflectors are seldom, 
if ever used. If a press roll is made too small in diameter and is 
running at high speed, it is almost impossible for the machine 
tender to pick off the paper. 

'. 208. Effects of Rubber-Covered Rolls. — When the papers 
being made on the machine differ in weight and quality, the 
amount of pressure on the top roll is varied by shifting the weight 
on the levers that operate on the journals of the top roll. Since 
the amount of deflection of the roll varies directly as this pres- 
sure varies, the initial crowning of the rolls is not suited to every 
condition of working. The maximum efficient action of the 



crown is possible only between comparatively narrow limits of 
variation in position of the weights. The use of rubber covering 
largely increases the limits of effective working pressure of a 
particular crown, as compared with the same crown on a similar 
roll that is not rubber covered. Unfortunately, the rubber, in 
adjusting itself to working conditions, largely increases the width 
of contact between the two rolls; this increases the area of contact 
and decreases the specific pressure, which lessens the de-watering 
action of the press. In brief, the rubber covering of a press 
roll corrects for faultj^ crown and preserves the felts; but it lets 
the paper go to the dryers containing a larger proportion of 
moisture than if a plain roll were used; and the softer the rubber 
the more pronounced is this last effect. 

Although having greater de-watering power, hard rubber or 
metal rolls possess the following disadvantages: felt meshes fill 
and become hard much more quickly; this causes breaks at the 
press due to felt marks and to small lumps becoming crushed 
while passing through the press; causes loss of time, due to 
frequent washing of felts; and it shortens the life of the felt, 
because of frequent washing and the lack of cushion in hard- 
rubber covered rolls. 

210. Felts taken from a press whose rolls are covered with 
hard rubber are seldom really worn out; rather, they have lost 
just enough of the nap to make them thinner and too hard to 
give good results with hard rolls; since thin, napless felts fre- 
quently mark the paper. Two weeks, or 12 running days of 24 
hours each, is about the Umit of running time for felts on hard 
rolls. Further, when hard rolls are used, it is necessary to wash 
felts at least once every 24 hours. 

If rubber of the proper hardness (density) be used, the running 
time of felts between washings will be largely increased, and the 
life of the felts will therefore be greatly lengthened; in fact, 
felts may then be used for four or five weeks, or even longer. 

If there is a disadvantage in using soft rolls, it is because they 
need more frequent grinding; a soft roll should be ground about 
once in every two months. However, a roll covered as stated 
will easily give 3 to 4 years' run, if properly used and not allowed 
to corrugate. 

211. Troubles Peculiar to Rubber Coverings. — A rubber 
covering corrugates or gets uneven in lines parallel to the axis 


of the roll, if the rubber is subjected to too much pressure. This 
effect is generally caused by the roll being crowned either too 
much or too little, and because the machine tender is obliged 
to carry too much weight on his levers in order to get an even 
pressure between the rolls across the machine. The longer Hfe 
of a soft-rubber covered roll will more than counterbalance the 
expense of grinding the roll, when this is compared with the loss 
of felts and paper production that are inevitable consequences 
of the use of hard rolls. Hard rolls have also a further dis- 
advantage, in that they have a decided tendency to check, 
and these check marks, or small cracks, must be ground out as 
often, nearly, as the soft roll requires grinding to remove its 

The density (hardness) of rubber-covered rolls that give satis- 
factory service should be measured with a plastometer, sclero- 
meter, or a similar instrument; the results thus obtained should 
be noted and should be insisted upon when drawing up specifica- 
tions for use in ordering new rolls. 

Each maker indicates the density of his rubber covering differ- 
ently; thus, one maker indicates the density for the first and 
second press rolls by 4f and for the third press by 5; another 
uses A. 11 and A.3 for the same purpose; etc. The proper 
designations must be obtained from the makers' catalogs. 

212. Crown of Rolls. — In general, it is probable that too much 
crown is given the lower roll, the elastic quality of the rubber 
covering being depended upon to counterbalance any irregu- 
larities in dressing the roll. 

The following table gives, approximately, the proper crown for 
lower press rolls when they are being ground; and the values 
here specified are sufficiently exact for all practical purposes, 
unless the design of the roll itself varies extremely from general 
shop practice. The table gives the crowning for rubber-covered 
rolls for the first and second press; for the third press, reduce the 
values 5%. Thus, for a 20-inch roll for a first or second press 
having 180 inches length of face, the crowning is (see table) .104 
inches; for a third press, this should be .104 X (1 — .05) = .104 
X .95 = .0988, say .099 inches. The figures here given for the 
crowning indicate how much larger the diameter of the roll should 
be at the middle than at the ends. It is assumed that the rolls 
are made with cast-iron bodies and that they are of standard 








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213. Construction and Sizes.-^The shells of the felt rolls should 
be of such quality and thickness that, for any specified diameter, 
thej^ may have sufficient strength to withstand the strains 
induced by the continuous reversal of stress, which is due to the 
turning of the roll in the grip of the pulling felt. Consider, for 
instance, a felt roll 8 inches in diameter, to be used on a high- 
speed news machine. Such a roll may revolve on its own axis 
sa}^ 300 times in a minute, giving 600 reversals of stress in that 
time. Some day, this action must crystallize the metal at the 
point of greatest bending moment, just as a wire can be broken by 
continually bending it back and forth. The life of these rolls 
depends on the selection of good material, proper thickness and 
diameter of shell, and they should be in dynamic balance. Use 
as few rolls as possible on the outside of the felt ; each is a dirt 
catcher, and eacli deposits dirt on the paper side of the felt. 

214. Proper Balancing of Rolls. — A roll is in static balance 
(neutral equilibrium) when it can be placed with its axis hori- 
zontal, its journals resting on knife edges, and have no tendency 
to roll or turn. A roll is in dynamic balance when it turns 

Fig. 62. 

steadily in its bearings at high speed, A roll may be in static 
balance and not in djmamic balance, as will now be explained. 
Referring to Fig. 62, suppose A, B, C, and D are weights placed 
inside the shell. If A and B are equal in weight and shape, are 
situated equally distant from the axis of the roll, are placed on 
opposite sides, but at opposite ends, the roll will be in static 
balance. If C and D are of different weights and shapes, C 
being lighter than D and farther from the axis, D may be so 
placed that the roll will still be in static balance. If the roll is 
turning swiftly in its bearings, weights A and B not being directly 
opposite each other will impart to the roll a wobbly motion. 
Since C and D are not of equal weight and are situated at unequal 
distances from the axis ^f re volution, the centrifugal force exerted 
by D and the section of the shell adjacent to D is not quite the 
same as that exerted by C and the section of the shell adjacent to 
C. At very high speeds, the difference between these two values 


for centrifugal force becomes considerable, and it puts additional 
stresses and strains on the roll and on the bearings. This matter 
of dj'namic balance becomes especially important in connection 
with Fourdrinier table rolls. 


215. Definition of Draw. — At this point, it is advisable to 
consider the effect of faulty draws of paper between the presses. 
The draw is the pulling the paper receives as it passes from one pair 
of rolls to another; for example, between couch rolls and the first 
press rolls, between the rolls of the first and second presses, the 
second and third presses, last press and dryers, drj^ers and cal- 
ender, and calender and reels. The term is especially applicable 
to the gaps at the wet end, where the paper gets about all of 
its longitudinal stretching, which is caused by each press running 
faster than the one that precedes it. 

216. Correcting Faulty Draws. — If the paper is too tight be- 
tween the couch rolls and the first press, and between the presses, 
it may get narrow, even though the deckles have not been 
moved, and the trim at the slitters may be getting dangerously 
narrow. In such cases, bring the various presses more nearly to a 
uniform speed by speeding up the slow ones or slowing down the 
fast ones. The trouble may have arisen through changing the 
weights on one press, or because of a change in character of stock. 
Many paper makers are too afraid of a slack draw between 
presses; a slack draw is a good thing, provided it is not loose 
enough to crease the paper. Always remember that the less 
a paper is stretched on the machine the stronger it is. The 
control of the draw has been improved by the development of the 
electric drive, described in Vol. V. 

Sometimes a paper machine is not quite in alinement, and the 
paper may show a tendency to travel to one side, even arriving 
at the calenders 4 inches or more to one side. This fault can be 
corrected by putting a leading roll with the proper "cant," 
obliqueness, between the last press and the dryers, thus guiding 
the paper back again to the center of the dryer rolls. 

217. A Cause of Winder Trouble. — A great deal of the trouble 
experienced with calenders and winders on high-speed machines 
is due to faults at the press part. Failure to press the paper to a 
uniform thickness is especially liable to cause trouble on the uni- 
form speed reels and winders. 


(PART 2) 


(1) Explain how the paper is transferred from the wire to the 

(2) What factors affect the percentage of solids in the paper as 
it comes to the press part? 

(3) What factors affect the percentage of solids in paper going 
from the press part? 

(4) About what is the limiting percentage of solids obtainable 
in paper by pressing in the press part of the paper machine? 

(5) (a) What is the nature and purpose of the press-rol) doctor ? 
Why should it be oscillated? 

(6) (a) How is the paper transferred from the first press to the 
second? (6) from the last press to the dryers? 

(7) Why is the paper reversed at the last press? 

(8) Explain the purpose and operation of the felt guide roll? 

(9) (a) Describe a felt suction box? (6) What is the advan- 
tage of using it? 

(10) A press has the following lever system? 

(11) Name some advantages of a suction press roll. 

(12) Describe the method of putting on a new felt. 

(13) What precautions should be taken when putting on a felt? 

(14) (a) What is usually meant by "felt mark"? (6) how is 
it remedied? 

(15) Mention some points on the care of felts. 

(16) What is the effect of tension on felts? 

(17) What is meant by crowning a roll? Why is it necessary? 
How much crown is required for a roll 160 inches wide and 24 
inches in diameter. ? 

§6 139 


(18) What is the effect of incorrect crown of the press roll on the 

(19) Compare the effects of small hard- and soft-rubber rolls. 

(20) Explain (a) the term "draw;" (6) the danger in a slack 
draw; (c) in a tight draw. 



(PART 3) 



218. Passing from Last Press to Dryers. — The paper has now 
been followed from the breast roll of the Fourdrinier part until 
it has passed, with its direction reversed, through the nip of 
the last press of the press part. The paper has been picked off 
by the machine tender and passed over the paper roll, which is 
carried by brackets on top of the last part of the press rolls. This 
part, like all other paper rolls, unless driven, must be set in motion 
before the paper is passed over it. From this point, the paper is 
put through the smoothing press; or, if there is no smoothing 
press, the paper is passed directly into the dryer section, dryer 
part or dryer nest, as it is variously termed. But if the last press 
be not reversed, the paper comes straight through with the felt, 
and it can be passed directly to the smoothing press or dryers. 

The paper at this point will contain 60% to 70% of water. 
In this condition, it requires less pressure to smooth out the 
inequalities in the surface that are due to impressions of the wire 
mesh and the weave of the felts than when the paper is dry and 
hard. It is also possible to print what is practically a water- 
mark by impressing steel type on the soft paper. Other designs 
may be produced in a similar manner. In some papers, the 
impressions of the felt and the bulk of the sheet are to be retained 
for special effects; but this can be secured and the paper flattened 
to a uniform thickness, by means of a properly adjusted pair of 
§6 141 




smoothing rolls, no felt being used between these rolls. When 
the paper is finished at the calenders, there is a greater likelihood 
of injuring the fibers. Calender finishing depends more on 
friction for its results, and the weight on the paper is enormously 
greater. The smoothing press is most applicable to the making 
of book papers. 

219. The Smoothing Rolls. — Fig. 63 shows a pair of smoothing 
rolls, A and B, which are mounted on the dryer frame at the end 
nearest the last press rolls K of the press part. The top press 
roll A is rubber covered, while the lower press roll B has a gun- 

FiG. 6.3. 

metal or bronze shell. These rolls may' be so made that they 
can be reversed; that is, the rubber-covered roll can be placed 
on the bottom and the metal-covered roll on the top. Some 
paper makers prefer to have the rolls interchangeable with the 
brass and rubber rolls, respectively, of the wet press. It should 
be noted that wood (maple) and stone rolls may also be used. 
The required difference in hardness may also be obtained by 
using two rubber rolls of different degrees of hardness. The 
paper P is shown as passing over the top of the upper roll, back 
through the nip between the two rolls, and from there to the 
first lower dryer D, against which it is held by the dryer felt F. 
Attention is called to the ductor X, which guides the paper into 
the nip of the smoothing press; also, to the doctor Y, which 
scrapes the paper off the lower smoothing roll, so it will drop 


between the dryer felt and the first lower dryer D. If desired, 
the paper can be passed directly from the last press K through 
the nip between the two smoothing rolls. 

Each succeeding unit of the paper machine runs a little faster 
than the preceding one, to prevent the paper from running back 
on a roll and catching on a doctor. This causes a draw (see Art. 
215, Part 2) between successive units, which requires careful 
attention and is a frequent cause of breaks. Adjustment is 
made by shifting a belt on a cone gear of a mechanical drive, 
etc., or by means to be described later in connection with an 
electrical drive. 

220. Crowning the Roll. — The rubber roll is compressible 
and resilient, thus assuring a perfect contact across the machine, 
if accurately crowned and covered with rubber of the proper 
density. The correct crowns to be used as a guide in grinding 
these rolls have been given in Part 2 of this Section. Since the 
design of a press roll varies in accordance with the ideas of differ- 
ent paper-machine manufacturers, the crowns there specified 
may not quite suit all makes of rolls; but, for the first grinding, 
they are accurate enough to work satisfactorily within the 
range of control given by the weights and levers. 

By carefully studying the smoothing press and its functions as 
here described, the machine tender can form his own opinion, 
in any particular case, as to whether it is better to pass the paper 
over the top roll or directly through the nip, and whether to have 
the rubber or the bronze roll on top; either change reverses the side 
of the sheet in contact with the rubber roll. In deciding such 
matters, always take into account the matter of risk of injury to 
the man that passes the paper, and use that arrangement which 
will be the safer for him. 

221. Finish of Paper. — The whole question of finish of paper 
can be solved by straight thinking. First find out what finish is 
required, whether it is to be rough, smooth, or glazed. A 
glazed finish is obtained by crushing the surface of dry paper after 
a superficial dampening or sweating; a smooth finish, by the use 
of pressure rolls or breaker calenders in the drj^er nest. M. G. 
or machine glazed paper is made on a Yankee machine, which 
is fully described in Vol. V. 

222. Adjusting the Pressure. — A method of adjusting the 
pressure between the rolls, one that is used quite generally on 


smoothing-press installations, is shown in Fig. 63. At R, a 
stationary revolving nut, which is usually turned by means of a 
ratchet handle, is used to bring the two rolls together. One 
of the rolls is covered with chalk and is brought into contact with 
the other roll by means of the two ratchets, one on either side of 
the machine, until no light can be seen between them; the rolls are 
then separated, and the width of the chalk mark that is impressed 
on the unchalked roll, preferably the rubber roll, will show by 
its character, whether even or uneven, the degree of pressure 
between the rolls with respect to uniformity. If the position of 
the weights and the position of the screws with respect to the 
ratchets be plainly marked by center-punch or chisel marks when 
the transferred chalk mark is even all the way across the machine, 
then this machine can be easily adjusted when running to give 
uniform pressure when doing its work as a smoothing press. 

223. Definition. — There is sometimes a misunderstanding as 
to the meaning of the words "ductor" and "doctor," as used in the 
industry. In this textbook, the term ductor refers to any device 
for leading (conducting) the paper into a nip. The word 
doctor, on the other hand, refers to a scraper that is used to keep 
the surface of a roll clean. 


224. Purpose of the Dryers. — The dryer section of a paper 
machine consists of a set of cast-iron cylinders, connected and 
driven by a train of gears, and heated by steam, the steam so used 
being exhaust or low-pressure steam. Most machines have a 
dryer felt or canvas, to support and carrj'^ the paper and hold 
it in contact with the cylinders, which are usually called the 
dryers. Heat from the steam is conducted through the dryer 
shells to the paper and evaporates the moisture (water) in the 
paper; the resulting vapor is absorbed by an air current, and is 
carried outside the building. In passing over the dryers, the 
moisture content of the paper will be reduced from an original 
state of 60%-70% to 6%-8% on leaving the dryers; this means the 
removal of about 2 pounds of water per pound of finished paper. 

It is necessary to provide means for removing the moisture- 
laden air from the room and, also, for removing from the dryers 
the,water that results from the condensation of the steam ; methods 
for accomplishing this will be described later. 




225. The Two Parts of the Dryer Section. — ^Fig. 64 shows a 
typical dryer part. It consists of a 
smoothing press A, 30 48-inch (diam- 
eter) dryers D, and 2 36-inch felt 
dryers B. In this case, the paper passes 
through the smoothing press, and the 
dryers are driven by gears at the back. 
There are two upper felts and two 
lower felts. The first upper felt and 
the first lower felt partially enwrap the 
first 8 (left-hand) upper dryers and the 
first 8 lower dryers, respectively. The 
first upper felt and first lower felt have 
each a felt dryer B, an automatic guide 
roll C (see also Fig. 66), and an auto- 
matic stretch roll E (see also Fig. 67). 
The second upper felt and the second 
lower felt partially enwrap the 7 upper 
dryers and the 7 lower dryers, respect- 
ively, at the right end of the nest (sec- 
tion); they both have an automatic 
guide roll G and an automatic stretcher 
F, but no felt drj'^er. The felt on the 
first-felt dryer is more efficiently placed 
as shown, because the dryer felts are 
damper at this point than at any other 
place in the dryer nest, and the dried 
felt immediately takes up paper again. 
The reader is advised to take a pointer 
that will not mark the diagram, Fig. 64, 
(a knitting needle will do), and follow, 
first, the run of the felts throughout the 
nest; then follow, second, the run of the 
paper. Follow the run of the felts first, 
beginning with the lower felt, because 
it first receives the paper. The circles 
in solid lines represent dryers, the larger 
ones in dotted lines are the gears. 

226. Course of the Felts. — Beginning 
with the felt roll H, below the smooth- 
ing press, follow the lower felt throughout [its entire length 


until the starting point is again reached. This felt (canvas 
wraps around approximately one-third of the circumference 
of the first (left-hand) dryer D. The felt touches about one-half 
of the surface of each dryer after the first; it passes under the 
first four dryers and over the first four felt rolls (not counting the 
first roll H), reaching at this point the two rolls Ri and Ro, over 
the pinion P. As the felt comes up from under the eighth lower 
dryer, over the felt roll, and down on its return journey, it first 
passes around a hand guide roll Ki. This last is simply a felt 
roll, one journal of which rests in bearings on a bracket, which can 
be moved by means of a hand screw; the hand screw itself is 
fixed, and it works in a bracket base, as in a nut, to move the 
bracket in the desired direction. The hand guide roll may be 
located elsewhere; in fact, it is a principle that the lead of a felt 
to a guide roll should be as long as possible. 

The dryer felt then travels back until it comes to the automatic 
stretcher E, which is more fully described later. This stretcher 
automatically takes in the slack of the dryer felt by means of 
weights, which are suspended on a carriage, the chain holding the 
weights passing over a pulley that is between the stretcher and 
the weights. The position in which the stretcher is here shown is 
probably due to some local condition or some personal idea of 
the designer; it were better to place it nearer the hand guide roll 
or nearer the first return of the felt, like the stretchers shown at 
El and Fi in the two upper felts, and at F in the second lower felt. 

From the automatic stretcher, the felt passes over an auto- 
matic guide roll C, which is more fully described later. This 
guide roll has bearings on brackets that swing on pivoted levers. 
When the felt travels too much to one side, it pushes against a 
finger on the lever at that side, which pushes the bearing forward 
and forces the felt to travel toward the other side. To obtain 
sensitive automatic action of the guide, the distance between the 
nearest roll back of the guide roll and the guide roll itself should 
be at least 6 feet, and preferably much greater, the best distance 
being determined by local conditions. 

After leaving the automatic guide roll, the felt comes to the 
felt dryer B. Concerning the value of a felt dryer, there is a 
difference of opinion. Insofar as dr\'ing the paper goes, a felt 
dryer is probably not the equal of an extra dryer in the dryer 
section; but dr3Mng the felt is supposed to keep the felt from 
rotting, and it thus makes the felt last longer. 


In the manner just outlined, the reader is advised to follow the 
course of the other three felts. Some machines have only one 
lower and one upper felt; some have no upper felt, but if the 
dryer nest be driven as two parts, the felt must be divided. 

227. Prevention of Accidents. — The felt roll H under the 
smoothing press is so placed that the paper from the smoothing 
press can be easily dropped between the felt and the first lower 
dryer without any danger of crippling the back tender's hands. 
A pony dryer or lead roll is often used, and occupies the position 
of the smoothing press. Too much stress cannot be laid on the 
necessity for extreme care, not only in passing the paper through the 
dryers but also in considering and selecting the best position for 
the dryer-felt rolls between the dryers. The danger points are 
where the back tender is required to pass the paper in between the 
felt and dryer, when both felt and dryer surfaces are moving so as 
to draw the hand in ; the points where the paper is to be taken out 
are obviously less dangerous. It is a good thing to move all the 
felt rolls over as far as practicable, to make the receiving angle as 
wide as possible. No point of machine efiiciency should be con- 
sidered important enough to warrant the increase of any risk to 
the operator, beyond the absolute minimum obtainable. 

228. Some Troubles and Their Remedies. — Troubles on a 
machine can sometimes be remedied by increasing the lead 
between the felt roll and the guide roll in the direction in which 
the felt is travehng. If the felt is getting wet after passing the 
automatic stretcher, and there is a felt dryer on that felt, take 
some weights off the automatic stretcher, thus avoiding the 
strain due to any subsequent shrinking. 

A felt drj^er that is situated as in Fig. 64, will tend to cause the 
felt to pull very strongly on the nearest felt rolls. If the felt 
gets wetted by vapors after it leaves the automatic stretcher, 
and before it reaches the felt drj^er, the pull may be so great as to 
bend the rolls slightly. 

The reader is advised to follow the course of the other three 
felts shown in Fig. 64 in a manner similar to that just described 
for the first lower felt. 

229. Course of the Paper. — The course of the paper will now be 
followed from the smoothing press to the spring roll N, around 
which it passes before entering the calenders. As the paper 
leaves the smoothing press, it is dropped between the felt and 


the first lower dryer D, Fig. 64, passes under the dryer, comes 
up on the other side, and a httle wad is tucked between the felt 
and the first upper dryer. After passing the first upper dryer, 
it is taken by the back tender and passed to the entering side of 
the second lower dryer; it is thus passed under each lower dryer 
and up over the next succeeding upper dryer until it leaves the 
last upper dryer and is thrown up into the top nip of the calen- 
ders; sometimes it is thrown over the top roll, depending on which 
side of the stack the first nip is. The spring roll A^ automatically 
takes care of variations in tension. The reader should follow the 
course of the paper on Fig. 64, from one end of the dryer nest to 
the other. 

A very helpful device for taking the tail over the dryers is the 
Sheahan rope carrier. This consists of a pair of endless ropes 
that are carried in grooves on the front ends of the dryer surface. 
They travel close together, except where they are made to 
approach each other at the first dryer so as to grip the end of the 
tail placed between them. The back tender follows the paper 
along, so as to pass it b}'^ hand in case of a break. In another 
patented device, compressed air is used to pass the paper from 
dryer to dryer, and from the last dryer to the calenders. 

Doctors are sometimes used on dryers to prevent the paper 
from winding round them. 

230. Steam Joints and Driving Gear. — Fig. 65 is a cross- 
sectional view of the dryer nest shown in Fig. 64. The felt rolls 
R, the felt dryers B, the top and bottom dryers D, D, all have 
the same reference letters as the corresponding parts in Fig. 64. 
The steam joints M, shown connected to the back hollow journals 
J of the dryers, are piped to two pipe headers *S and E. The 
larger pipe S supplies steam to the dr3'er, while the smaller pipe 
E is Si drain that carries away the water of condensation. The 
steam joints are described later. 

The gears that drive the dryers are shown at G, and a platform 
or walkway for the operators is shown at K. In this case, the 
felt dryers B are driven by the felt, and they have no gears; this is 
good practice, but the bearings must be kept in first-class 

231. Dryers to Be Kept Free from Water, Air and Grease. — It 

is essential, in order to dry paper well and evenly all over, that 
the dryers be kept free from water, air, and grease. An air valve 




on the front head of the dryer, which may be a small pet cock, 
will prevent accumulation of air, if opened at intervals. The 
air acts as a blanket, to prevent heat getting to the dryer shell. 
The water that collects in the dryer, because of the condensation 
of the steam, is emptied by either a siphon or a dipper, as will be 

Fig. 65. 

described later. Some heating systems are designed to sweep 
the air out of the dryers by circulation of steam. 

The dryer part should be started turning over before any 
steam is admitted into the dryers, in order to prevent the unequal 
strains that are produced when hot steam enters a cold dryer 
that contains a body of cold water in its bottom ; in such a case, 


the top of the diyer heats and expands more than the bottom, 
and thus tends to get out of shape. 

Oil acts as a coating, on the inside of the dryer, preventing 
transfer of heat; it may get into the steam from the lubrication 
of the engine piston and should be caught in an oil separator. 
If it gets into the dr3'er, it nia}' be nnnovcd by treatment with a 
hot solution of soda ash. 



232. General Principle.— On all carrying rolls, the felt will 
come to the side that, the felt touches first, regardless of whether 
the roll be inside or outside of the felt. If one end of any roll be 
moved toward the direction of travel of the felt, the felt will 
come toward the end so moved; except, that if the moving of the 
end of the roll causes the roll to stop or causes its speed to slacken 
until the speed of the roll is slower than that of the felt, the felt 
will then slide the other way. All guide rolls should be provided 
with a swivel box on the end opposite the end of the roll 
moved. Ordinary carrying rolls should not be moved very far 
out of alinement. 

233. Automatic Guide for Dryer Felts. — A typical design for 
an automatic guide for dryer felts is shown in Fig. 66. The felt 
on its way from the felt roll R passes under the rod S and over 
and between the two fingers F, F. These fingers are attached 
to the rod S by small clamps and bolts, as shown, and can be 
moved along this rod in order to adjust the distance between 
them to suit different widths of felts. When the felt is running 
straight and the fingers are properly spaced, about ^ inch farther 
apart than the width of the felt, the outside edges of the felt will 
not touch the inside of the fingers, but will pass through freely. 
The fingers hang downwards, as shown in view (6), and they are 
of sufficient length to partly support the felt as it passes over 
them. When the felt begins to travel out of line, it will touch 
and push against one of the fingers, say at a, view (6), and this 
will cause one end of the bell-crank lever KL to move. This 
lever turns easily on the pointed pivots P, which are supported 
by the brackets B, The arms L carry the bearings E for the 




ends of the felt roll on which the felt travels. The arms K are 
connected by the cross shaft *S; hence, in the case of the felt 
traveling toward either side, the felt roll is moved by this action, 
one journal of the I'oll being advanced and the other being pulled 
back, in proportion to the effort made bj^ the felt to get out of 
line. A roll always tends to move any body touching it in a line 
perpendicular to its axis; consequently, the automatic stretch 
roll here described acts to force the felt to correct its own errors 
of travel and keep it in line. It will be noticed that the journal 

Fig. 66. 

of the guide roll that is on the side toward which the felt is 
traveling is always advanced, while the journal on the other side 
of the machine is simultaneously pulled back. As the result of 
this action, the guide roll is quickly shifted by the felt when it 
runs out of line, and in such a manner that the axis of the roll is 
thereby made perpendicular to the direction the felt must 
travel to correct its own error. 


234. Automatic Stretcher for Dryer Felts. — An automatic 
dryer-felt stretcher is shown in Fig. 67. The felt F is wrapped 
half way around a felt roll R, whose journal runs in a bearing 
that is carried by trolley wheels C, a similar journal, bearing, etc. 




being on the other end of the roll. The trollej's C on either side 
of the machine are caused to move simultaneously by the shaft S, 
which extends across the machine. Therefore, when pulleys A 
and B on one side turn, the corresponding pulleys on the other 
side turn also; and they turn the same distance at the same time, 
because all these pulleys are keyed to the shaft S. This device 
keeps one end of the stretcher roll from being pulled ahead of the 
other, and thus shifting the felt. 

The weights W, which are hung on chains D that grip the chain 
slots on pulleys A on both sides of the machine, tend to turn 
shaft S with a force that is proportional to the number of weights 
hung on these chains; and they are generally so calculated as to 

A-B B A 


Fig. 67. 

give a pull of about 2 pounds per inch of width of felt. The pull 
of the weights on pullej^s A tends to turn shaft S, and also pulleys 
B, which are at the ends of the shaft in line with the trolleys C. 
The chains on the trolleys are furnished with turn buckles K, to 
permit of accurate adjustment. The chains are also attached 
to the rims of pulleys B; so that, as these pulleys tend to turn, 
the chains pull on trolleys C and, therefore, on the felt that is 
wrapped around the felt roll carried by trolleys C. The trolleys 
move easily on the guide rails T\ and when the pull of the felt 
slackens, the weights automatically pull on the trolleys until the 
proper tension is obtained. 

235, Felts Should not be too Tight or too Loose. — The machine 
tender should form the habit of watching the automatic felt 
tightener, to observe its condition; if in good condition, this will 
be indicated by a constant movement in one direction or the 
other. If the tightener always remain still, it should be examined ; 
it is then probably out of order and may require lubricating, or it 
may be gripped between the rails, or the chains may have shpped 
off the pulleys. If the automatic stretch roll does not work 
properly, report it to the millwright. A felt that is too tight or 
too loose will spoil paper very quickly, causing uneven drying and 


cockling; since the felt rolls may be pulled out of line, if the felt 
is too tight, or the felt may be hanging loose because the slack 
is not being taken up. 

The old-fashioned felt tightener did not have sufficient capacity 
to take up all the slack in a long felt. This type of stretcher is 
still used on dryer felts, and it will take up a certain amount of 
slack; but it is necessary to install also a hand-stretching device 
that is similar in design to the hand felt stretcher. 

236. The Dancing Roll.— A very sensitive and direct-acting 
stretcher for a dryer felt is a dancing roll ; this rests in a loop of the 
felt, the entire weight being carried by the felt. Brackets are 
bolted to the dryer frames, and the bearings of the roll are free 
to move up and down the vertical slots in the brackets. The 
"return" felt rolls, over which the felt runs to make the loop, are 
supported in brackets bolted to the slotted brackets. This is a 
good type of dryer-felt stretcher; its principal failing is that it is 
limited in its range of action by the height of the vertical slots in 
the brackets. Another drawback is that one end may get into a 
higher position than the other, which w^ould cause the roll to act 
like a guide roll and shift the felt to one side of the machine. 

237. Amount of Stretching and Shrinking. — The purpose of the 
automatic stretcher is to take up the slack of the felt when the 
paper leaves the machine for any cause, as a break at the wet end 
or a shut down. A 60-yard felt will shrink 3 feet at the very 
least when it is wet, and it lengthens a like amount in a few minutes, 
when the paper is off the dryers. On the average, a brand new 
felt will shrink and stretch considerably more than this, some 
felts as much as 6 feet. The old-stjde swing stretcher did not 
give enough leeway to take care of this shrinkage; and if the felt 
were tightened up sufficiently to run straight and guide properly, 
it was too tight when it became wet. 

After putting on a new felt, it should be weighted down until 
it is fairly tight; and it should be run around a few minutes 
before passing the paper over it, to let the felt straighten. After 
the felt is perfects straight and the paper is passed over the 
machine, the machine tender should watch the automatic stretcher, 
to see that it is easing up as the felt gets shorter. If the felt is 
getting crooked, it is a sign that there are not enough weights, for 
a slack felt will almost always run crooked. When a good auto- 
matic stretcher is in proper workingorder and is well adjusted, the 




stretch roll should tremble — move back and forth slightly — 
every time the dr3^er-felt seam passes over it. 

238. Guiding Felts by the Stretch Roll. — Some stretchers 
stretch with the felt, i.e., move in the direction of travel of the 
felt; others move in the opposite direction. 

To show how the stretch roll may be used to guide the felt, 
consider Fig. 68, in which either A ov B maj^ be the stretch roll ; if 
A be the stretch roll, then B is the reef, or fixed, roll, and vice 

Fig. 68. 

versa. Suppose the felt to be travehng in the direction indicated 
by the arrows, that T is the tight side, and that S is the slack side. 
If, now, the roll A be shifted toward the tight side, so its axis 
EF makes an angle FEF' with its former position, the felt will 
go to the slack side, in the direction of the arrow H; but if B be 
shifted toward the tight side, so its axis CD makes an angle DCD' 
with its former position, the felt will go to the tight side in the 
direction of the arrow K. The roll A acts just like the carrying 
rolls mentioned in Art. 232, while B checks in the opposite 
direction. The felt traveling from the under side of A to 5 
does not count in this connection. 

The dryer-felt stretcher is one of the most important parts of 
the machine to know how to handle. If, for any reason, the felt 
gets beyond control and gets partly off the machine, moving 


the stretcher 2 inches out of hne will guide the felt more quickly 
and surely than all the carrying rolls together. 

The wet felts or woolen felts will always go to the slack side of 
the stretcher, except, very rarely, in the case of a new felt, which 
may go to the tight side for a few hours. 

Dryer canvas felts are not made endless. Wool dryer felts, 
sometimes used on ver\^ fine paper, are made endless. Many 
European machines use endless, wool dryer felts. 


239. Necessity for Removing Water. — It was stated in Arts. 
224 and 231 that the steam in the dryers is continually condensing 
into water as the paper passes over the dryers. The water that 
collects in the dryers must be removed, since the presence of even 
a small quantitj^ of water prevents the quick and uniform drying 
of the paper. Two methods are employed for getting rid of this 
water: in one, dippers or scoops are attached to the dryer and 
turn over and around with it, scooping up the water to the center, 
from whence it flows out of the hollow journal; in the other, a 
siphon, which remains stationary and dips down to the bottom of 
the dryer, is used. 

240. Dippers. — Both dippers and siphons require some form 
of stuffing box or steam joint on the end of the journal, to admit 
steam into the dryer and let out water without loss of steam or 
leakage of water. 

Fig. 69 shows a dryer fitted with a steam joint, a double dipper, 
and an interior steam distributing pipe P, which is so perforated 
that the entering steam is distributed to all parts of the dryer. 
The two dippers D are formed of open channel irons, of such a 
shape and bolted to the dryer head H in such a manner, that they 
scoop up the contained water, when the dryer revolves in the 
direction indicated by the arrow. The water enters the open end 
of the scoops; and, as they are raised by the turning of the dryer, 
the water that is scooped up flows along the channel and is 
dumped into the receiving chamber C. This chamber is a cast- 
iron receptacle, so equipped with baffles and guides inside as to 
guide the in-coming water in such a way that it is forced out 
between the inside of the rear journal J and the outside of the 
steam pipe P. When the water reaches the steam joint, it flows 




out through passages E into the pipe W, and from thence on to the 
main drain pipe below. In the front head is a manhole M; T is 

a pet cock, which allows the escape 
of air when starting up, and breaks 
the vacuum when shutting down over 
Sunday. Air is a good non-conductor 
of heat; and if it be not removed, it 
will make a blanket next the inside 
of the shell and prevent efficient 
transfer of heat and drying of the 
paper. The air vent is sometimes put 
in the cap of the front journal K, 
which is then drilled through. 

241. Another type of dipper extends 
in sections across the dryer, and is 
attached to the dryer shell. Its oper- 
ation can be compared with the action 
of scooping up water in a dustpan and 
raising it until the water runs down 

= the handle and into one's sleeve, the 
'i sleeve corresponding to a pipe that 
carries the water off. The pipe that 
receives the water from the scoop is 
horizontal; it extends through the 
center of the dryer, and it conducts the 
water to the steam joint. It is obvious 
that a dipper cannot work when the 
dryer is stationary; but the steam 
continues to condense, whether the 
dryer is stationary or not. 

242. Siphons. — One end of a dryer 
F is shown in Fig. 70; it is equipped 
with a siphon Ki. The steam inlet 
is shown at H; K is the water (con- 
densed steam) outlet, and G is the 
stuffing box and steam joint. As be- 
fore stated, the siphon remains station- 
ary while the dryer revolves. The 

lower end of the siphon pipe must clear the bottom of the dryer 
at least half an inch, in order to make certain that the dryer clear 




the pipe as it turns; this keeps foreign substances from collecting 
and catching the siphon pipe, thus forcing it to turn with the 
dryer. Sometimes the pipe is carried around and left sticking 
up instead of down. The siphon pipe here shown is not of good 
design, because the sharp bend in it does not allow of the pipe 
being put in or pulled out through the journal. A longer pipe, 
one that reaches nearly to the other end of the drj^er in a long, 
gentle curve, could be inserted and withdrawn readil}^, and with- 
out removing the head. 

Fig. 70. 

When the bottom end of the siphon is covered with water, the 
higher pressure in the dr^-er is exerted on the surface of the water, 
forcing it up through the siphon and out through the hollow 

243. Comparison of Dippers and Siphons. — There is a great 
diversity of opinion as to the relative merits of siphons and 
dippers. It is a matter of fact, however, that both low-speed 
and high-speed machines are running satisfactorily when 
equipped with either siphons or dippers. In any comparison of the 
two, it should be kept in mind that the essentials of any good 
drying system are to keep the dryers free of air and of condensate, 
and to prevent the escape from the machine of uncondensed 
steam. The dippers fill the last two requirements perfectly, 


because they will pick up water and discharge it from the dryers 
to a trap; but some other means must be provided for getting 
the air out of the dryers. In many cases, air cocks are placed 
on the face of the dryers or are tapped into the ends of the 
journals, which are drilled for this purpose. Siphons, on the 
other hand, require a steady, continuous pressure drop between 
the inside of the dryer and the water header in order to lift the 
condensate from the dryer; therefore, a more complicated 
arrangement is needed to prevent the loss of uncondensed steam, 
as, for example, special, individual air-vented traps or a circu- 
lating system, both of which arrangements are described later. 
The siphon is the ideal method of removing air from the dryer. 

The modern open-trough, double dipper is probably as satis- 
factory as any design of dipper for removing water. But, since 
a dipper is a revolving part of the machine, it must be balanced ; 
also, great care must be taken that neither a dipper nor a siphon 
become loose, and thus be a noisy, useless nuisance, rattling 
around inside the dryer. 

It should be noted that there is a critical speed of dryer, at 
which the water is kept thrown against the inside of the dryer 
shell by centrifugal force, lying in a comparatively uniform 
layer over the whole inside of the cylindrical surface. 

Dippers will operate successfully in 48-inch dryers up to a 
paper speed of 600 feet per minute, and siphons to nearly this 
speed. For higher speeds of paper, dryers of larger diameter 
should be used. 

244. The Steam Joint. — The rubbing surfaces of the moving 
and stationary parts of the steam joint are shaped like a ball 
fitting into a socket. The ball is ground into the socket until 
only a slight pressure on the ball will make the joint both water 
tight and steam tight. The shape of this joint, see Fig. 70, 
allows the part of the joint that is bolted to the hollow journal 
of the dryer to turn with the dryer, and its ball-like end fits 
snugly while turning in the cup-hke socket of the part of the 
joint that is attached to the piping. These joints should be 
tight when the side bolts joining the two parts are only a little 
more than hand tight. If the joint is not steam tight when given, 
say, a quarter of a turn of the wrench over hand tightness, it 
should be taken off at the end of the week, when shutting down, 
and re-ground. These joints can be tightened so hard as to stop 
the paper-machine engine. 


If the surfaces of the ball-and-socket joint are scored by grit or 
other foreign matter, the joint must evidently be re-ground 
before it can again give good service. When first installed, 
steam joints are sometimes equipped with springs, which are so 
proportioned as to take care of a maximum of, say, 20 pounds 
per square inch; but new springs must be furnished that are 
suitable for higher pressures, when a higher pressure will ulti- 
mately be used on the dryers. The springs should never come 
coil on coil, as such a condition, when cold, would induce a very 
powerful drag or brake on the dryer when the spring became 

245. Lubricating the Joint. — The lubricant best suited to a 
steam joint should have sufficient body to keep the rubbing 
surfaces free from contact with each other under the maximum 
pressure; but it should possess the greatest fluidity possible under 
these conditions. It should also have a high temperature of 
decomposition, and should be free from all tendenc}^ to corrode 
the surface of the metal. The writer has found a good grade of 
cylinder oil to be most satisfactory. 

Never put waste in the oil pans, because it is then impossible 
to tell whether the oil hole is open and the joint being lubricated 
or whether the waste is merely being oiled. If the pressure on 
the moving surfaces of a steam joint is too great, i.e., if the 
joint is too tight, the joint acts as a brake of considerable power; 
and if the machine tender allows the steam joints to be tightened 
every time they leak, instead of re-packing or repairing them, 
he is not only wearing out the joints but he is also putting an 
unnecessarj' load on the driving-shaft belts and the engine, thus 
wearing out equipment and wasting power. 



246. Conditions for EflBlcient Operation of Dryer Part. — The 

dryer part depends on three principal factors for its efficient 
operation: first, on the arrangement of the piping that supplies 
steam and removes condensation from each dryer; second, and 
this is almost as important, on the proper control of the felt 
tension; third, on the proper supply of dry air in the right place to 




carry away the water. Probably most of the moisture (water) 
leaves the paper between the dryers, not while covered with the 
felt. The slight pressure of the moist air next the paper when 
so covered is relieved on contact with the air, and opportunity 
is given for the evaporating moisture to be absorbed. 

247. Necessity for Having Free Circulation of Steam. — The 

main object to be aimed at in piping up the drj-ers is to keep up a 
free circulation of the steam. Steam is a non-conductor of 
heat; and since a stationary body of steam transmits heat 
slowly, by convection, the outside of such a body of steam may 
lose a large part of its heat, while the inside remains at nearly 
its original temperature. To maintain a constant supply of 
heat, which will give a uniform temperature across the face of the 
dryer and thus insure uniform drying across the sheet of paper, 
it is necessary to keep the steam on the move inside the dryer 
shell. To accomplish this, there must be a difference in pressure, 
which should be about half a pound per square inch between 
the steam header and the dryer and another half pound between 
the drj'er and the water or drain header. 

248. A Steam-Pressure Controlling System. — One method of 
obtaining approximately these conditions and forcing circulation 


of steam is indicated in Fig. 71. The steam header, or supply 
pipe, is shown divided into two sections by distributing valve 3, 
both sections being again divided by two other distributing 
valves 3, so the proportion of steam to each section can be 
controlled. The exhaust steam from the engine passes through 
the diaphragm-operated valves 2, which are automatically 
controlled, so that the total quantity of steam to the dryer nest is 
varied in accordance with the pressure in the dryers. If, in 
drying the paper, more steam than usual is condensed, thus 


causing the pressure in the dryers to drop, this causes the dia- 
phragm to open valve 2 and let more steam into the system. 
If the steam pressure in the dryers gets too high, this diaphragm, 
which is controlled by air pressure, shuts valve 2, and the steam 
pressure is brought back to normal. The steam that is admitted 
through valve 2 is distributed to the two ends of the dryer part, 
in the proportion desired, by valves 3, which are adjusted by the 

The water header is divided into four parts, the three flanges 
13 being blanks; this is done to keep the pressure in the water- 
header sections from getting so high as to exceed the steam 
pressure in any dryer. With a piping arrangement of this kind, 
by changing the pressure in the water header, the paper maker 
can have more pressure in any one of the four sections of the 
dryer part than in any of the others ; at the same time, the steam 
in the higher pressure part cannot escape through the water 
header and, by thus communicating with the others, raise the 
pressure in any dryer in those sections in which the paper maker 
wants a low pressure. 

249. Other Steam-Circulating Systems. — Various means of 
circulating the steam in the dryer part have been patented and 
installed. Some cause the high-pressure steam to enter one 
section, pass through the dryers and the water header into a 
second section of dryers, and so on, if desired, into a third section; 
this method maintains a rapid circulation of steam and gives 
good results. The idea is to dry the paper gradually, by having 
the hotter, high-pressure steam affect the hot, nearly dry paper 
first. Heating the paper gradually is less likely to produce 
blisters and cockling. 

250. Special Considerations. — The paper maker must re- 
member that special drying systems are expensive and often 
troublesome, if not carefully installed and operated. A few iron 
filings, a piece of a washer, or a piece of putty, which may happen 
to get into the piping or into a valve, will cause a great deal of 
trouble, and will be hard to find after the system is closed. It 
should be a rule never to alter a dryer-pipe installation when the 
machine is doing well; if there be something wrong, try to ascer- 
tain^what it is and endeavor to devise a remedy. If the dippers 
and^siphons are in good condition, get the air out of the dryers 
by means of pet cocks in the heads. Put a steam gauge on the 


steam header and on the water header ; then, if the water-header 
reading is equal to or greater than the steam-header reading, 
change the gauges. If the water-header reading still shows 
high, blank off the part that is getting the most steam, thus 
preventing high pressures elsewhere in the pipe. 

The temperature of the dryers must be accurately controlled 
and maintained uniform; otherwise, some rolls of paper will be 
too wet and some too dr3^ The thinner the layer of air between 
the dryer and the paper the better is the dr3dng. Excessive 
drying is also a source of breaks on the dryers, the paper winding 
around a dryer and often necessitating the stopping of the 
machine to get it off. 

251. Automatically Controlling the Steam Supply. — Nearly 
every paper machine is driven by a steam engine or a steam 
turbine, and their exhaust steam should furnish all the heat 
required for drying the paper under normal conditions. But 
papers differing in quality and weight require different amounts 
of steam in drying. There are three general methods of obtain- 
ing automatic control of the steam supply; they are based 
on (a) condition of the paper, (6) pressure in the dryer, and (c) 
temperature in the dr3'er. 

By method (a), a light roll, on free arms, rides on the paper as it 
passes from one drj'er to the next; it is situated near the middle 
of the dryer part, and one of the arms is connected to an appa- 
ratus for operating a steam valve, so as to admit more or less live 
steam to the dryers. If the paper is too damp, it slackens, the 
roll fall^, and the steam valve opens; but if the sheet is too dry, 
this operation is reversed. When once adjusted to the speed 
and weight of the paper, this device works well. 

Methods (6) and (c) are similar in principle, the reason for 
classifying them separately being that a pressure gauge does not 
take account of the small amount of superheat that the steam 
sometimes possesses. The steam in the dryer is generally in a 
saturated condition, in which case, the pressure gauge gives an 
accurate measure of the temperature as well as of the pressure. 
In either case, the result is, practically speaking, thermostatic 
control, and the dryer temperature is maintained constant when 
the apparatus is set for particular paper conditions. 

252. Steam Traps. — Steam is one of the most valuable com- 
modities used in the mill; and, next to water, it is the most easily 


wasted. A large amount of steam is required for drying paper, 
and the profits of the mill may depend on how efficiently it is 
used. To prevent steam from blowing through the siphon or 
dipper and still permit the escape of the condensation, steam 
traps are used. There may be one trap to each dryer; more 
frequentl}', however, there is one trap for several dryers, or even 
a single trap for all the dryers. 

The purpose of the steam trap is to hold the steam in the 
drj-ers until it has condensed and given up all its latent heat. 
In changing from a pressure of, say, 10 pounds per square inch, 
gauge, to pound per square inch, gauge (atmospheric pressure), 
a pound of steam gives up only 9.8 B.t.u.; but when the steam at 
atmospheric pressure condenses to water of the same temperature 
and pressure, it gives up 970.4 B.t.u., or nearly 100 times as much. 
Steam at 10 pounds pressure is, of course, hotter, i.e., has a higher 
temperature, than at atmospheric pressure; consequently, in 
some systems, the hot steam is carried as steam through a section 
of the diyer part, to be condensed in another section, that next 
the presses. This permits the passage of more heat at a lower 
temperature, which is the best way to dry paper. 

254. Types of Steam Traps. — There are two general types of 
steam traps — the bell type and the tilting type. The former 
consists essentially of a chamber, in which hangs a bell that is 
constrained to move vertically. The steam and the condensate 
enter under the bell. Steam escapes under the bell, which rises 
as the water gathers, until, at a certain point, a water discharge 
is opened and the steam-exhaust supply is temporarily^ closed. 
The water is forced out, and the bell falls until it operates to 
close the water discharge opening, the steam outlet being again 
opened. An air vent over the bell lets out the non-condensible 
gases. The hot water goes back to the boiler, and the separated 
steam is generally sent to one or more dryers at the wet end, 
usually through a common header, which connects all the traps. 

The second (tilting) tj'pe of steam trap is essentially^ a two- 
pocket cylinder, mounted at the middle of the long axis. Steam 
and water enter at one end, the steam passing baffles and escap- 
ing; the water accumulates until that end is heavier than the 
other, when it falls. This movement shuts off the steam inlet 
and outlet, and it opens the water outlet; at the same time, the 
water outlet from the other end is closed, while the steam inlet 
from the dryers and the outlet from the trap are opened. In 


some traps, a tilting bucket is enclosed in the vapor chamber; 
it is operated by the weight of water condensed in the bucket. 

In some systems, a vacuum pump removes water and air from 
the traps. The pressure in the trap is, of course, always lower 
than in the dryer. 

When it is decided to use valves on each drj^er, on both the 
steam supply and the water discharge, and a trap is used on each 
dryer, then the valve on the water discharge is closed only 
when it is necessarj'^ to repair the trap. The valve on the steam 
supply will control the quantity of steam to the drj^er. Under 
these circumstances, a good siphon performs uniformly as long 
as the steam pressure is uniform and the paper machine is 
running uniformly. 

Traps are always liable to get out of order; and if there are too 
many, some are always out of commission. It pays to use good 

255. Air Pumps. — Methods involving forced steam circula- 
tion by means of air pumps are unexcelled, when they receive 
constant attention. But the human factor in the problem is a 
large one, and few paper mills can thus afford to complicate their 
paper-making facilities. 

256. Control at the Press End of Dryer Part. — The steam 
supply to the press end of the dryer part should be capable of 
easy control by the paper maker. A valve on each of the first 
few dryers will enable him to cut the supply, if the surfaces of 
the dryers become hot enough to spoil the paper; and such a 
condition will soon be manifested by the surfaces of the dryers 
becoming covered with fluff or filler. 

The paper at the calender end should still contain 8 % or 9 % 
of moisture, because paper that is over-dried is spoiled. In all 
finer grades of paper, the use of a smoothing press before the 
first dryer, when the paper still contains at least 60% of water, 
will compress the fiber into the surface and, at the same time, 
compact the body of the paper, so that a better finish can be 


257. Importance of Controlling Felt Tension. — The control 
of the tension of the felts is a most important feature of the 
management of dryers. Efficient and uniform drying action 


of the drj'cr surfaces can be obtained only by securing a close 
and uniform contact between the paper and the dryers. A careful 
inspection of the felt tension throughout the nest will often 
indicate adverse conditions, either because the felt tightener is 
badly placed or because it does not have sufficient range and 
promptness of action as a felt loosener. A dryer felt, if made of 
cotton, will shrink violenth' when it is locally wet, and it will 
slacken promptly as it dries. If the tighteners, or as they may 
trulj' be called, loosening devices, are not so placed as to nullify 
the evil effects of this shortening and lengthening of the felt, the 
life of the felt and the quantity and quality of the output will 

258. Putting on a New Felt. — The proper method for putting 
on a new felt will now be described. First, slack up on the 
tighteners, and then cut the old felt right across the machine. If 
there is no old felt on the machine, a length of good stout twine, 
of hemp or sisal, must be threaded through the dryers, in the 
middle, following exactly the path of the felt around the dryers, 
felt rolls, tighteners, etc. The new felt, which comes in a roll, 
is then laid down across the machine, between the last dryer and 
the calenders, or the size press, if there be one. The end is cut 
square; if necessary, ravellings from the cut part are used for 
sewing the ends together later on. The end of the new felt is then 
sewed to the end of the old felt ; or, if there is no old felt, the end of 
the new felt is attached to the end of the threaded twine. The 
drj-ers are then started up. If the lower felt is being replaced, 
the new felt goes down under the dryers; the other loose end of 
the old felt is taken, as it comes out, and is passed over the top of 
the calenders, to be wrapped around a reel drum and wound up. 
When the last of the old felt comes out, the end of the new felt 
is detached from it, and is sewed tightly to the other end of the 
new felt. The two ends of the felt are placed together, the edges 
pointed in, and the seam is sewed about 1 inch in. 

The seam is conveniently made b\' tacking the loose ends, 
joined squarely, to a board, with about H to 2 inches extending. 
Following a thread, a straight line is drawn across the felt. A 
long ravelling, as long as can be handled without snarling, is 
threaded into a sailmaker's needle, and the two ends are sewed 
together on the mark. A good stitch is to put the needle down 
about I inch from the edge, up about 2 inches along the line, down 
again through the first hole, up through a new hole 4 inches from 


the first, down again through the second hole, and so on. A 
quicker method is to pass up and down alternately, every 2 inches 
or so. For a nice job, the ends should be inside the felt, so as not 
to mark the paper; but they are often left outside, since it is 
then much easier to sew. 

A top felt is replaced in the same manner as that just described, 
except that the old felt cannot then be passed so conveniently^ 
over the calenders and wound on a reel drum. In this case, the 
old felt is either rolled on a core by hand, or it is wound up on the 
last lower drj^er roll, the sweat roll, or in any way that is con- 
venient; frequently, a roll is started on a core, and then wound 
by resting it on, or between, dryers. 

259. Strength of Felts. — Dryer felts, unlike press felts, are 
usually made of cotton instead of wool, and are sometimes j inch 
thick. They are much stronger than press felts, having a break- 
ing strength of 300 pounds per inch of width; the breaking strength 
of the average press felt is about 60 to 70 pounds per inch of 
width, though a fine- writing, third-press felt of a tissue machine 
ma}' have a breaking strength sometimes of 125 pounds per inch 
of width. 

260. Starting the Felts. — The great strength of a cotton dryer 
felt, in conjunction with its decided shrinkage when wet, cause 
tremendous strains on the dryer felts and rolls. In starting up a 
dryer part with a new felt or, for that matter, with an old felt, 
start the dryers free of paper; run slowly, with the felt stretchers 
slack at first, watching the tighteners and guides, to see that all 
the rolls turn and that the felt does not catch anywhere. 

Turn steam into the dryers for about 20 minutes before starting 
up and look to see that the dryers are empty of water. If a 
dryer be practically half full of cold water, it will act as a sweat 
roll, and the drj^er edge next the back side will get wet from the 
vapors there ; this will not only spoil the paper but may also result 
in the loss of a dryer felt. When run cold, dryers are Ukely torust 
and mark fine papers. 

261. When putting on a dryer felt, it may tend to run to the 
front side or back side of the machine, notwithstanding that every 
precaution has been taken to keep the run of felt straight and to 
sew the seam square across. In correcting this, the machine 
tender should bear in mind the simple rule : A dryer felt will run 
to the tight side when tightened at the side at which it leaves the dryer 


cylinder; and it will run to the slack side when tightened on the side 
that is going to the cylinder. 

The seam should always be squared up on starting, and any 
tendencj^ to run ahead on either side can be corrected by making 
the travel of that side longer; if this be not done, the felt will be 
unevenly stretched, and it will give plenty of trouble before it has 
been in service very long. 

When shrinking, a dryer felt can exert a pull of 30 pounds or 
more per inch of face of felt rolls, unless the stretch roll automatic- 
ally compensates for the shrinkage. This puts a bending moment 
on a felt roll, which will cause it to sag in the middle until the felt 
becomes too loose at the middle and too tight at the edges. The 
result is that the paper is not held tightly against the drj^ers and 
remains wet in the middle; and when the local felt-tension con- 
ditions change, a break is almost inevitable. In any case, a good 
roll at the winder is practically impossible. Cockling troubles 
also result from these conditions, because minute bubbles of 
steam make small blisters in the paper, and lack of pressure 
imparts a sort of puckering to the paper as it dries. 

262. Flapping. — Often when following the course of the paper 
through the dryer nest, the observer will perceive a continuous 
flapping of the dryer felts at certain points. This flapping is 
almost invariably caused by inaccurate spacing of the dryer 
gears, or in some imperfection of the drive. Many old machines 
have been speeded up in order to increase production, and the 
result aimed at has been lost because of continual breaks of paper 
in the dryer nest, due to the use of the old-fashioned cast gears. 
The remedy is always to order cut gears when the paper speed is 
over 250 feet per minute. By watching a flapping felt and count- 
ing the flaps per revolution of a dryer, the relationship between 
the drive and the flap will be perceived. 

Flapping of drj'-er felts may also be caused by an eccentric dryer, 
one that does not rotate about its axis; it may likewise be caused 
by a warped dryer. To ascertain whether or not a dryer is 
eccentric or is warped, hold a stationary pointer close to the 
revolving dryer surface; if the revolving surface is always the 
same distance from the pointer, the dryer is turning true, but if 
not, it is eccentric or warped, and the degree of eccentricity can be 
readily noted. 

A lack of symmetry of a drying cylinder, due either to eccen- 
tricity of its bearings or to its not being a true cylinder, will 


produce a circumferentially imperfect movement about the axis 
of revolution, which causes a flapping movement of the paper as 
it journeys from one dryer to another; and this occurs if either or 
both of two successive dryers are imperfect. Flapping is some- 
times due to a lack of proper balance between the speed of the 
paper, the diameter of the dryers, and the relative position of the 

263. Cause of Breaks. — It is well to note here that a dryer that 
is not properly machined, so that the foundry skin is removed, is 
liable, if not well "seasoned" before being machined, to become 
misshapen when subjected to the strains caused by the changes 
of temperature that are a part of the operation of paper drying. 
Man}^ a break may be caused by the stress of the paper resulting 
from a misshapen dryer or an eccentric dryer movement. The 
distortion of the dryer movement may be inherent in the dryer 
itself, or it may be due to unevenly worn bearings or to imperfect 
gears. Broke may be the result, however slight the non-uni- 
formity of the dryer travel. The reason that the paper does not 
break oftener when flapping occurs is because of the natural 
elasticity of a fabric composed of cellulose fibers. 

The driving side of a nest of dryers will sometimes exhibit this 
phenomenon when it is not evident on the tending side, because 
the bearings on the driving side are not as easily lubricated ; they 
may, for that reason, wear more rapidly, thus producing a rela- 
tively imperfect mechanical movement. 

264. It requires time to evaporate the water in the paper and 
change it into steam on the dryer, and time to remove the vapor 
from the paper as it travels from dryer to dryer. Paper shrinks 
as it dries, and it stretches as it becomes damp, and if the air it 
meets is moisture laden, the paper becomes cooled and dampened 
between dryers, if the length of lead is too great for the speed of 
the paper; such a condition is another cause for flapping. 

265. The Spear and Its Use. — When paper breaks and winds 
around a dryer, it must be cut off with a spear. The spear is a 
long, light pole, with a sharp steel head that is sometimes slightly 
curved. It is jabbed under the edge of the paper, as low as 
possible on the up-coming side of the dryer, and is pushed as far 
as possible; but it is withdrawn when the cut is at the highest 
point, as the dryer turns. A new jab is made as the cut again 
comes up, until the paper is cut clear across. It is a good plan 



to run the cut part over to the next dryer and along the lower 
tier. On a fast machine, the paper is immediately broken at the 
press or wire, and the dryers are slowed down or stopped; this is 
quicker in the end, and is less dangerous. It is not safe to stay 
near the man who is using the spear. 


266. Conditions for Maximum Drying Effects. — In a dryer 
nest, the diameter of the dryers being as large as possible, the 
maximum drying or evaporating effect per dryer should be 
imparted to (i.e., as much water should be evaporated from) 
the paper as can be taken care of by the air that meets the paper 
between the dryers. 

Between certain limits, it is evident that it is possible to obtain 
the same actual and relative amounts of dryer contact and air 
contact for the paper as it travels on its way through the dryers, 
whatever be the diameter of the dryers, whether 48 inches or 60 
inches; these limits are determined by the width of the machine, 
because the diameter of the felt rolls must increase with the width, 
which influences the spacing of the drj^ers. 

267. It is important that the dryer nest be so designed that the 
paper will come in contact with a dryer before the felt binds it to 
the dryer; and it is important that the felt should leave the paper 
before the paper is constrained to leave the dryer. 

In considering the relative position of dryers and the distance 
between the paper and dryer contacts, it must be remembered 
that the gears are all of the same diameter, and that the alternate 
upper and lower gears are in mesh; there must be clearance 
between gears on contiguous lower dryers and contiguous upper 
dryers, and this rule can be altered only by the use of idler gears. 

268. To recapitulate : in order to obtain the maximum output 
from a given nest of dryers under normal working conditions, 
the following practical conditions must be met. 

(a) The drj-ers must be perfect cylinders, revolving on true 
mechanical journals, whose axes should coincide with the theo- 
retical axes; the gears must be accurately cut and accurately 
connected with the dryers. 

(6) The length of contact of the paper with each dryer and 
with the air between the dryers must be adjusted to prevent 


(c) The paper must meet each dryer before the felt, and must 
leave the dryer after the felt, every time. 

269. Ventilation. — Good results cannot be obtained from the 
dryer nest unless the ventilation conditions are such that an 
ample supply of moderately dry air is constantly rising around 
the dryer nest. From 2 to 3 tons of water must be carried away 
by the air for each ton of paper made; and if the air supply is not 
ample, good drying conditions are not possible. A homely 
comparison that may serve to impress the idea on the reader's 
mind is : a washerwoman prefers a windy day to dry the clothes, 
even when the sun is not shining, to a sunshiny day when there 
is no air stirring; but the best day is when there is a warm, dry 

270. Amount of Water Evapo