LIBRARY
OF THE
UNIVERSITY OF CALIFORNIA.
Class
Gas-Engines and
Producer-Gas Plants
A PRACTICE TREATISE SETTING FORTH THE PRINCI-
PLES OF GAS-ENGINES AND PRODUCER DESIGN, THE
SELECTION AND INSTALLATION OF AN ENGINE, CON-
DITIONS OF PERFECT OPERATION, PRODUCER-GAS
ENGINES AND THEIR POSSIBILITIES, THF CARE OF GAS-
ENGINES AND PRODUCER-GAS PLANTS, WITH A CHAP-
TER ON VOLATILE HYDROCARBON AND OIL ENGINES
BY
R. E. MATHOT, M.E.
Member of the Socie'te' des Ingenieurs Civils de France, Institution of
Mechanical Engineers, Association des Ingenieurs de
1'Ecole des Mines du Hainaut of Brussels
TRANSLATED FROM ORIGINAL FRENCH MANUSCRIPT BY
WALDEMAR B. KAEMPFFERT
WITH A PREFACE BY
DUGALD CLERK, M. INST. C.E., F.C.S.
ILLUSTRATED
NEW YORK
THE NORMAN W. HENLEY PUBLISHING COMPANY
132 NASSAU STREET
1905
Copyright, 1905, by
THE NORMAN W. HENLEY PUBLISHING COMPANY
Also, Entered at Stationers' Hall Court, London, England
All Rights Reserved
COMPOSITION, ELECTROTYPING AND PRESS-
WORK BY TROW DIRECTORY, PRINTING AND
BOOKBINDING COMPANY, NEW YORK, U. S. A.
PREFACE
TO
"MATHOT'S GAS-ENGINES AND
PRODUCER-GAS" PLANTS "
BY
DUGALD CLERK, M.lNST.C.E., F.C.S.
MR. MATHOT, the author of this interesting work,
is a well-known Belgian engineer, who has devoted
himself to testing and reporting upon gas and oil
engines, gas producers and gas plants generally for
many years past. I have had the pleasure of knowing
Mr. Mathot for many years, and have inspected gas-
engines with him. I have been much struck with the
ability and care which he has devoted to this subject.
I know of no engineer more competent to deal with
the many minute points which occur in the installation
and running of gas and oil engines. I have read this
book with much interest and pleasure, and I consider
that it deals effectively and fully with all the principal
detail points in the installation, operation, and testing
of these engines. I know of no work which has gone
so fully into the details of gas-engine installation and
up-keep. The work clearly points out all the matters
which have to be attended to in getting the best work
V
14 1860
vi Preface
from any gas-engine under the varying circumstances
of different installations and conditions. In my view,
the book is a most useful one, which deserves, and no
doubt will obtain, a wide public recognition.
DUGALD CLERK.
March, 1905.
INTRODUCTION
THE constantly increasing use of gas-engines in the
last decade has led to the invention of a great number
of types, the operation and care of which necessitate
a special practical knowledge that is not exacted by
other motors, such as steam-engines.
Explosion-engines, driven by illuminating-gas, pro-
ducer-gas, oil, benzin, alcohol and the like, exact
much more care in their operation and adjustment
than steam-engines. Indeed, steam-engines are regu-
larly subjected to comparatively low pressures. The
temperature in the cylinders, moreover, is moderate.
On the other hand, the explosion-motor is irregu-
larly subjected to high and low pressures. The tem-
perature of the gases at the moment of explosion is
exceedingly high. It is consequently necessary to re-
sort to artificial means for cooling the cylinder; and
the manner in which this cooling is effected has a very
great influence on the operation of the motor. If the
cooling be effected too rapidly, the quantity of gas
consumed is considerably increased; if the cooling be
effected too slowly, the motor parts will quickly de-
teriorate.
In order to reduce the gas consumption to a mini-
mum, a matter which is particularly important when
vu
viii INTRODUCTION
the motor is driven by street-gas, the explosive mixture
is compressed before ignition. Only if all the parts
are built with joints absolutely gas-tight is it possible
to obtain this compression. The slightest, leakage past
the valves or around the piston will sensibly increase
the consumption.
The mixture should be exploded at the exact mo-
ment the piston starts on its working stroke. If igni-
tion occur too soon or too late, the result will be a
marked diminution in the useful effect produced by
the expansion of the gas. All ignition devices are
composed of delicate parts, which cannot be too well
cared for.
It follows from what has thus far been said that the
causes of perturbation are more numerous in a gas than
in a steam engine; that with a gas-engine, improper
care will lead to a much greater increase in consump-
tion than with a steam-engine, and will cause a waste
in power which would hardly be appreciable in steam-
engines, whether their joints be tight or not.
It is the purpose of this manual to indicate the more
elementary precautions to be taken in the care of an
engine operating under normal conditions, and to ex-
plain how., repairs should be made to remedy the in-
juries caused by accidents. Engines which are of less
than 200 horse-power and which are widely used in a
small way will be primarily considered. In another
work the author will discuss more powerful engines.
Before considering the choice, installation, and oper-
ation of a gas-engine, it will be of interest to ascertain
INTRODUCTION ix
the relative cost of different kinds of motive power.
Disregarding special reasons which may favor the one
or the other method of generating power, the net cost
per horse-power hour will be considered in each case
in order to show which is the least expensive method
of generating power in ordinary circumstances.
R. E. MATHOT.
MARCH, 1905.
TABLE OF CONTENTS
CHAPTER I
PAGE
MOTIVE POWER AND COST OF INSTALLATION . . i
CHAPTER II
SELECTION OF AN ENGINE
The Otto Cycle. The First Period. The Second Period. The
Third Period. The Fourth Period. Valve Mechanism. Ignition.
Incandescent Tubes. Electric Ignition. Electric Ignition by
Battery and Induction-Coil. Ignition by Magnetos. The Piston.
Arrangement of the Cylinder. The Frame. Fly- Wheels. Straight
and Curved Spoke Fly-Wheels. The Crank-Shaft. Cams, Rollers,
etc. Bearings. Steadiness. Governors. Vertical Engines.
Power of an Engine. Automatic Starting . . . . . . 21
CHAPTER III
THE INSTALLATION OF AN ENGINE
Location. Gas-Pipes. Dry Meters. Wet Meters. Anti-Pulsators,
Bags, Pressure-Regulators. Precautions. Air Suction. -Exhaust.
Legal Authorization 69
CHAPTER IV
FOUNDATION AND EXHAUST
The Foundation Materials. Vibration. Air Vibration, etc. Exhaust
Noises 87
xi
xii CONTENTS
CHAPTER V
WATER CIRCULATION
Running Water. Water-Tanks. Coolers .
CHAPTER VI
LUBRICATION
Quality of Oils. Types of Lubricators Ill
CHAPTER VII
CONDITIONS OF PERFECT OPERATION
General Care. Lubrication. Tightness of the Cylinder. Valve-
Regrinding. Bearings. Crosshead. Governor. Joints. Water
Circulation. Adjustment . . . . .'. . . . . . 121
CHAPTER VIII
HOW TO START AN ENGINE. PRELIMINARY PRECAUTIONS
Care during Operation. Stopping the Engine 128
' CHAPTER IX
PERTURBATIONS IN THE OPERATION OF ENGINES AND
THEIR REMEDY
Difficulties in Starting.^-Faulty Compression. Pressure of Water in
the Cylinder. Imperfect Ignition. Electric Ignition, by Battery or
Magneto. Premature Ignition. Untimely Detonations. Retarded
Explosions. Lost Motion in Moving Parts. Overheated Bearings.
Overheating of the Cylinder. Overheating of the Piston. Smoke
arising from the Cylinder. Back Pressure to the Exhaust. Sudden
Stops . . . . . . . . . . ... . . 134
CONTENTS xiii
CHAPTER X
PRODUCER-GAS ENGINES
High Compression. Cooling. Premature Ignition. The Govern-
ing of Engines .... .........
CHAPTER XI
PRODUCER-GAS
Street-Gas. Composition of Producer-Gases. Symptoms of Asphyxi-
ation. Gradual, Rapid Asphyxiation. Slow, Chronic Asphyxiation.
First Aid in Cases of Carbon Monoxide Poisoning. Sylvester
Method. Pacini Method. Impurities of the Gases .... 165
CHAPTER XII
PRESSURE GAS-PRODUCERS
Dowson Producer. Generators. Air-Blast. Blowers. Fans.
Compressors. Exhausters. Washing and Purifying. Gas-
Holder. Lignite and Peat Producers. Distilling-Producers. Pro-
ducers Using Wood Waste, Sawdust, and the like. Combustion-
Generators. Inverted Combustion 174
CHAPTER XIII
SUCTION GAS-PRODUCERS
Advantages. Qualities of Fuel. General Arrangement. Generator.
Cylindrical Body. Refractory Lining. Grate and Support for the
Lining. Ash-pit. Charging- Box. Slide-Valve. Cock. Feed-
Hopper. Connection of Parts. Air Supply. Vaporizer. Pre-
heaters. Internal Vaporizers. External Vaporizers. Tubular Va-
porizers. Partition Vaporizers. Operation of the Vaporizers. Air-
Heaters. Dust-Collectors. Cooler, Washer, Scrubber. Purifying
Apparatus. Gas-Holders. Drier. Pipes. Purifying-Brush.
xiv CONTENTS
Conditions of Perfect Operation of Gas-Producers. Workmanship
and System. Generator. Vaporizer. Scrubber. Assembling the
Plant. Fuel. How to Keep the Plant in Good Condition. Care
of the Apparatus. Starting the Fire for the Gas-Producer. Starting
the Engine. Care of the Generator during Operation. Stoppages
and Cleaning 199
CHAPTER XIV
OIL AND VOLATILE HYDROCARBON ENGINES
Oil-Engines. Volatile Hydrocarbon Engines. Comparative Costs.
Tests of High-Speed Engines. The Manograph. The Continuous
Explosion-Recorder for High-Speed Engines. Records . . . 264
CHAPTER XV
THE SELECTION OF AN ENGINE
The Duty of a Consulting Engineer. Specifications. Testing the
Plant. Explosion-Recorder for Industrial Engines. Analysis of
the Gases. Witz Calorimeter. Maintenance of Plants. Test of
Stockport Gas-Engine with Dowson Pressure Gas-Producer. Test
of a Winterthur Engine. Test of a Winterthur Producer-Gas
Engine. Test of a Deutz Producer-Gas Engine and Suction Gas-
Producer. Test of a aoo-H.P. Deutz Suction Gas-Producer and
Engine 279
CHAPTER I
MOTIVE POWER COST OF INSTALLATION
THE ease with which a gas-engine can be installed,
compared with a steam-engine is self-evident. In
places where illuminating gas can be obtained and
where less than 10 to 15 horse-power is needed, street-
gas is ordinarily employed.* The improvements which
have very recently been made in the construction of
suction gas-generators, however, would seem to augur
well for their general introduction in the near future,
even for very small powers.
The installation of small street-gas-engines involves
simply the making of the necessary connections with
gas main and the mounting of the engine on a small
base.
An economical steam-engine of equal power would
necessitate the installation of a boiler and its setting,
the construction of a smoke-stack, and other acces-
sories, while the engine itself would require a firm
base. Without exaggeration it may be asserted that
the installation of a steam-engine and of its boiler re-
quires five times as much time and trouble as the in-
stallation of a gas-engine of equal power, without
considering even the requirements imposed by storing
the fuel (Fig. i). Small steam-engines mounted on
* Recent improvements made in suction gas-producers will probably lead
to the wide introduction of producer gas engines even for small power.
i8 GAS-ENGINES AND PRODUCERS
sa
COST OF INSTALLATION 19
their own boilers, or portable engines, the consumption
of which is generally not economical, are not here
taken into account.
So far as the question of cost is concerned, we find
that a 15 to 20 horse-power steam-engine working at
a pressure of 90 pounds and having a speed of 60 revo-
lutions per minute would cost about 16^3 per cent,
more than a 15 horse-power gas-engine, with its anti-
pulsators and other accessories. The foundation of
the steam-engine would likewise cost about 16^3 per
cent, more than that of the gas-engine. Furthermore
the installation of the steam-engine would mean the
buying of piping, of a boiler of 100 pounds pressure,
and of firebrick, and the erection of a smoke-stack hav-
ing a height of at least 65 feet. Beyond a little excavat-
ing for the engine-base and the necessary piping, a
gas-engine imposes no additional burdens. It may be
safely accepted that the steam-engine of the power
indicated would cost approximately 45 per cent, more
than the gas-engine of corresponding power.
The cost. of running a 15 to 20 horse-power steam-
engine is likewise considerably greater than that of
running a gas-engine of the same size. Considering
the fuel-consumption, the cost of the lubricating oil
employed, the interest on the capital invested, the cost
of maintenance and repair, and the salary of an engi-
neer, it will be found that the operation of the steam-
engine is more expensive by about 23 per cent.
This economical advantage of the gas over the steam-
engine holds good for higher power as well, and be-
20 GAS-ENGINES AND PRODUCERS
comes even more marked when producer-gas is used
instead of street-gas. Comparing, for example, a 50
horse-power steam-engine having a pressure of 90
pounds and a speed of 60 revolutions per minute, with
a 50 horse-power producer-gas engine, and considering
in the case of the steam-engine the cost of a boiler of
suitable size, foundation, firebrick, smoke-stack, etc.,
and in the case of the gas-engine the cost of the pro-
ducer, foundation, and the like, it will be found that
the installation of a steam-engine entails an expendi-
ture 15 per cent, greater than in the case of the pro-
ducer-gas engine. However, the cost of operating and
maintaining the steam-engine of 50 horse-power will
be 40 per cent, greater than the operation and main-
tenance of the producer-gas engine.
From the foregoing it follows that from 15 to 20
up to 500 horse-power the engine driven by producer-
gas has considerably the advantage over the steam-
engine in first cost and maintenance. For the develop-
ment of horse-powers greater than 500, the employment
of compound condensing-engines and engines driven by
superheated steam considerably reduces the consump-
tion, and the difference in the cost of running a steam-
and gas-engine is not so marked. Still, in the present
state of the art, superheated steam installations entail
considerable expense for their maintenance and repair,
thereby lessening their practical advantages and ren-
dering their use rather burdensome.
CHAPTER II
THE SELECTION OF AN ENGINE
EXPLOSION-ENGINES are of many types. Gas-en-
gines, of the four-cycle type, such as are industrially
employed, will here be principally considered.
The Otto Cycle. The term " four-cycle " motor, or
Otto engine, has its origin in the manner in which the
engine operates. A complete cycle comprises four dis-
tinct periods which are diagrammatically reproduced
in the accompanying drawings.
The First Period. Suction: The piston is driven
forward, creating a vacuum in the cylinder, and simul-
taneously drawing in a. certain quantity of air and gas
(Fig. 2).
FIG. 2. First cycle: Suction.
The Second Period. Compression: The piston re-
turns to its initial position. All admission and exhaust
valves are closed (Fig. 3). The mixture drawn in
during the first period is compressed.
21
22 GAS-ENGINES AND PRODUCERS
The Third Period. Explosion and Expansion: When
the piston has reached the end of its return stroke, the
compressed mixture is ignited. Explosion takes place
at the dead center. The expansion of the gas drives the
piston forward (Fig. 4).
FIG. 3.-^Second cycle: Compression.
FIG. 4. Third cycle: Explosion and expansion.
The Fourth Period. Exhaust: The piston returns
a second time. The exhaust-valve is opened, and the
products of combustion are discharged (Fig. 5).
te
FIG. 5. Fourth cycle: Exhaust.
These various cycles succeed one another, passing
through the same phases in the same order.
. OBJECTIONS TO THE SLIDE-VALVE 23
Valve Mechanism. It is to be noted that in mod-
ern motors valves are used which are better adapted to
the peculiarities of explosion-engines than were the
old slide-valves used when the Otto engine was first
introduced. The slide-valve may now be considered
as an antiquated distributing device with which it is
impossible to obtain a low consumption.
In old-time gas-engines rather low compressions were
used. Consequently a very low explosive power of the
gaseous mixture, and low temperatures were obtained.
The slide-valves were held to their seats by the pres-
sure of external springs, and were generously lubri-
cated. Under these conditions they operated regularly.
Nowadays, the necessity of using gas-engines which are
really economical has led to the use of high compres-
sions with the result that powerful explosions and high
temperatures are obtained. Under these conditions
slide-valves would work poorly. They would not be
sufficiently tight. To lubricate them would be difficult
and ineffective. Furthermore, large engines are widely
used in actual practice, and with these motors the fric-
tional resistance of large slide-valves, moving on exten-
sive surfaces would be considerable and would appre-
ciably reduce the amount of useful work performed.
By reason of its peculiar operation, the slide-valve
is objectionable, the gases being throttled at the time of
their admission and discharge. As a result of these ob-
jections there are losses in the charge; and obnoxious
counter-pressures occur. The necessity of using ele-
ments simple in their operation and free from the ob-
24 GAS-ENGINES AND PRODUCERS
jections which have been mentioned, has naturally led
to the adoption of the present valve. This valve is used
both for the suction of the gas and of the air, as well as
for the exhaust, with the result that either of these two
essential phases in the operation of the motor can be
independently controlled. The valves offer the follow-
ing advantages : Their tightness increases with the pres-
sure, since they always open toward the interior of the
cylinder (Fig. 6). They have no rubbing surfaces,
FIG. 6. Modern valve mechanism.
and need not, therefore, be lubricated. Their opening
is controlled by levers provided with quick-acting
cams; and their closure is effected by coiled springs
almost instantaneous in their action (Fig. 7). Each
valve, depending upon the purpose for which it is used,
can be mounted in that part of the cylinder best suited
for its particular function. The types of valved motors
now used are many and various. In order to attain
REQUISITES OF VALVES 25
I
economy in consumption and regularity in operation
they should meet certain essential requirements which
will here be reviewed.
Apart from proportioning the areas properly and
from providing a suitable means of operation, it is in-
dispensable that the valves should be readily accessible.
Indeed, the valves should be regularly examined,
FIG. 7. Controlling mechanism of valve.
cleaned and ground. It follows that it should be pos-
sible to take them apart easily and quickly.
It is necessary that the exhaust-valve be well cooled;
otherwise the valve, exposed as it is to high tempera-
tures, will suffer derangement and may cause leakage.
The water-jacket should, therefore, surround the seat
of the exhaust-valve, care being taken that the cooling
water be admitted as near to it as possible (Fig. 8).
The motor should control the air-let valve or that of
the gaseous mixture. Hence these valves should not
26 GAS-ENGINES AND PRODUCERS
be actuated simply by springs, because springs are apt
to move under the influence of the vacuum produced
by suction.
FIG. 8. Water-jacketed valve.
The mixture of gas and air should not be admitted
into the cylinder at too low a pressure; otherwise the
weight of the mixture admitted would be lower than it
REQUISITES OF VALVES 27
ought to be, inasmuch as under these conditions the
valve will be opened too tardily and closed prema-
turely. At the beginnings well as at the end of its
stroke the linear velocity of the piston is quite inade-
quate to create a vacuum sufficient to overcome the re-
sistance of the spring. It is, therefore, generally the
practice separately to control the opening or closing of
the one or the other valve (gas-valve or mixture-valve) .
Consequently these valves must be actuated independ-
ently of each other. Nowadays they are mechanically
controlled almost exclusively, a method which is ad-
vocated by well-known designers for industrial motors
in particular. Valves which are not actuated in this
manner (free valves) have only the advantage of sim-
plicity of operation. Nevertheless, this arrangement
is still to be found in certain oil and benzine engines,
notably in automobile-motors. In these motors it is
necessary to atomize the liquid fuel by means of aspired
air, in order to produce an explosive, gaseous mixture.
Ignition. In the development of the gas-engine, the
incandescent tube and the electric spark have taken the
place of the obsolete naked flame. The last-mentioned
mode of exploding the gaseous mixture will not, there-
fore, be discussed.
The hot tube of porcelain or of metal has the in-
disputable merit of regularity of operation. The meth-
ods by which this operation is made as perfect as
possible are many. Since certainty of ignition is ob-
tained by means of the tube, it is important to time the
ignition, so that it shall occur exactly at the moment
28 GAS-ENGINES AND PRODUCERS
when the piston is at the dead center. It has been
previously stated that premature or belated ignition of
the explosive mixture appreciably lessens the amount
of useful work performed by the expansion of the gas.
If ignition occur too soon, the mixture will be exploded
before the piston has reached the dead center on its
return stroke. As a result, the piston must overcome a
considerable resistance due to the premature explosion
and the consequent pressure. Furthermore, by reason
of the high temperature of explosion, the gaseous prod-
ucts are very rapidly cooled. This rapid cooling causes
a sudden drop in the pressure; and since a certain inter-
val elapses between the moment of explosion and the
moment when the piston starts on its forward stroke,
the useful motive effort is the more diminished as the
ignition is more premature.
Incandescent Tubes. In Figs. 9 and 10 two systems
most commonly used are illustrated. In these two ar-
rangements, in which no valve is used, the length or
height to which the tube is heated by the outer flame is
so controlled that the gaseous mixture, which has been
driven into the tube after compression, reaches the
incandescent zone as nearly as possible at the exact
moment when ignition and explosion should take place.
The temperature of the flame of the burner, the rich-
ness of the gaseous mixture, and other circumstances,
however, have a marked influence on the time of igni-
tion, so that the mixture is never fired at the exact
moment mentioned.
These considerations lead to the conclusion that
THE INCANDESCENT TUBE
29
motors in which the mixture is exploded by hot tubes
provided with an ignition-valve are preferable to valve-
less tubes. By the use of a special valve, positively
controlled by the motor itself, the chances of untimely
ignition are lessened, because it is necessary simply to
regulate the temperature and the position of the tube
in order that ignition may be surely effected imme-
FIGS. 9-10. Valveless hot tubes.
diately upon the opening of the valve, at the very mo-
ment the cylinder gases come into contact with the in-
candescent portion of the tube (Fig. 1 1 ) . Many manu-
*
facturers, however, do not employ the ignition-valve on
motors of less than 15 to 20 horse-power, chiefly because
of the cheaper construction. The total consumption
3 o GAS-ENGINES AND PRODUCERS
is of less moment in a motor of small than of great
power, and the loss due to the lack of an ignition-valve
not so marked. In a high-power engine, premature ex-
plosion may be the cause of the breaking of a vital
part, such as the piston-rod or the crank-shaft. For
this reason, a valve is indispensable for engines of more
than 2 oto 25 horse-power. A breakage of this kind is.
less to be feared in a small motor, where the parts are
FIG. ii. Ignition -tube with valve.
comparatively stout. The gas consumption of a well-
designed burner does not exceed from 3.5 to 5 cubic
feet per hour.
Electric Ignition. Electric ignition consists in pro-
ducing a spark in the explosion-chamber of the engine.
The nicety with which it can be controlled gives it an
undeniable advantage over the hot tube. But the ob-
ELECTRIC IGNITION
3 1
jection has been raised, perhaps with some force, that
it entails certain complications in installing the engine.
Its opponents even assert that the power and the rapid-
ity of the deflagration of the explosive mixture are
greater with hot-tube ignition. This reason may have
caused the hot-tube system to prevail in England,
where manufacturers of gas-engines are very numerous
and not lacking in experience.
Electric ignition is effected in gas-engines by means
of a battery and spark-coil, or by means of a small mag-
neto machine which mechanically produces a current-
breaking spark.
Electric Ignition by Battery and Induction-Coil.
The first system is the cheaper; but it exacts the most
FIG. 12. Electric ignition by spark-coil and battery.
painstaking care in maintaining the parts in proper
working condition. It comprises three essential ele-
ments a battery, a coil, and a spark-plug (Fig. 12).
The battery may be a storage-battery, which must, con-
sequently, be recharged from time to time; or it may be
3 2
GAS-ENGINES AND PRODUCERS
a primary battery which must be frequently renewed
and carefully cleaned. The induction-coil is fitted with
a trembler or interrupter, which easily gets out of order
and which must be regulated with considerable accu-
racy. The spark-plug is a particularly delicate part,
subject to many possible accidents. The porcelain of
which it is made is liable to crack. It is hard to obtain
FIG. 13. Spark-plug.
absolutely perfect insulation ; for the terminals deterio-
rate as they become overheated, break, or become foul
(Fig. 13). In oil-engines, especially, soot is rapidly
deposited on the terminals, so that no spark can be pro-
duced. In benzine or naphtha motors, such an accident
is less likely to happen. In automobile-motors, how-
ever, the spark-plug only too often fails to perform its
function. The one remedy for these evils is to be found
IGNITION BY MAGNETO
33
in the most painstaking care of the spark-plug and of
the other elements of the ignition system.
Ignition by Magnetos. Magneto apparatus, on the
other hand, are noteworthy for the regularity of their
operation. They may be used for several years with-
FIG. 14. Magneto ignition apparatus.
out being remagnetized, and require no exceptional
care. Magneto ignition devices are mechanically ac-
tuated, the necessary displacement of the coil being
effected by means of a cam carried on a shaft turning
with half the motor speed (Figs. 14 and 15). At the
moment when it is released by the cam, the coil is sud-
34 GAS-ENGINES AND PRODUCERS
denly returned to its initial position by means of a
spring. This rapid movement generates a current that
passes through terminals, which are arranged within
the cylinder and which are immediately separated by
mechanical means. Thus a much hotter circuit-break-
FIG. 15. General view and details of a magneto ignition apparatus.
ing spark is produced, which is very much more
energetic than that of a battery and induction-coil, and
which surely ignites the gaseous mixture in the cylin-
der. The terminals are generally of steel, sometimes
pointed with nickel or platinum (Fig. 16). The only
precaution to be observed is the. exclusion of moisture
MAGNETO IGNITION
35
and occasional cleaning. For engines driven by pro-
ducer-gas magneto-igniters are preferable to cells and
FIG. 16. Contacts of a magneto-igniter.
batteries. In general, electrical ignition is to be rec-
ommended for high-pressure engines.
In order to explain more clearly modern methods of
ignition a diagram is presented, showing an electric
FIG. 17. Device for regulating the moment of ignition.
magneto-igniter applied to the cylinder-head of a
Winterthur motor, and also a sectional view of the
member varying the make-and-break contacts which
36 GAS-ENGINES AND PRODUCERS
are mounted in the explosion-chamber (Figs. 18 and
19).
i. The magneto A consists of horseshoe-magnets,
between the poles of which the armature rotates. At
its conically turned end, the armature-shaft carries an
arm #, held in place by a nut.
FIG. 1 8. Winterthur electric ignition system.
2. The igniter C is a casting secured to the cylinder-
head by a movable strap and provided with two axes
D and Af, of which the one, Z), made of bronze, is
movable, and is fitted with a small interior contact-
hammer, a percussion-lever, and an exterior recoil-
spring; the other, M, is fixed, insulated, and arranged
A MODERN MAGNETO-IGNITER 37
9
to receive the current from the magneto A, by means
of an insulated copper wire E.
3. The spring F comprises two continuous coils con-
tained in a brass casing, and actuating a steel striking
or percussion-pin.
4. The controlling devices of the magneto include a
stem or rod G, slidable in a guide H, provided with a
FIG. 19. Contacts of the Winterthur system.
safety spring and mounted on an eccentric spindle, the
position of which can be varied by means of a regulat-
ing-lever (/) . The rod is operated from the dis-
tributing-shaft, on the conical end of which a cam J
carrying a spindle is secured.
Regulation of the Magneto. The position assumed
by the armature when at rest is a matter of importance
in obtaining a good spark on breaking the circuit. The
marks on the armature should be noted. The position
38 GAS-ENGINES AND PRODUCERS
of the armature may be experimentally varied, in order
to obtain a spark of maximum intensity, by changing
the position of the arm B on the armature-shaft.
Control of the Magneto. The controlling gear
should enable the armature to oscillate from 20 to 25
degrees. The time at which the breaking of the circuit
is effected can be regulated by shifting the handle (/).
In starting the engine, the circuit can be broken with
a slight retardation, which is lessened as the engine
attains its normal speed.
Igniter. It is advisable that there should be a play
of y<2, mm. (0.0196 in.) between the lever Z when at
rest and the striking-pin. The axis D of the circuit-
breaking device should be easily movable; and the
hammer which it carries at its end toward the interior
of the cylinder should be in perfect contact with the
stationary spindle Af, which is electrically insulated.
This spindle M should be well enclosed, in order to
prevent any leakage that might cause a deterioration of
the insulating material.
The subject of ignition is of such extreme impor-
tance that the author will recur to it from time to time
in the various chapters of this book. Too much stress
cannot be laid upon proper timing; otherwise there
will be a needless waste of power. Cleanliness is a
point that must be observed scrupulously; for spark-
plugs are apt to foul only too readily, with the result
that short-circuits and misfires are apt to occur. In
oil and volatile hydrocarbon engines the tendency to
fouling is particularly noticeable. In the chapter de-
THE PISTON
39
voted to these forms of motors the author has dwelt
upon the precautions that should be taken to forestall a
possible derangement of the ignition apparatus. As a
general rule the ignition apparatus installed by trust-
worthy manufacturers will be found best suited for the
requirements of the engine.
The apparatus should be fitted with a device by
which the ignition can be duly timed by hand during
operation (Fig. 17).
The Piston. Coming, as it does, continually in con-
tact with the ignited gases, the piston is gradually
FIG. 20. Design of the piston.
heated to a high temperature. The rear face of the
piston should preferably be plane. Curved surfaces
are not to be recommended because they cool off
badly. Likewise, faces having either inserted parts
or bolt-heads are to be avoided, since they are liable to
become red-hot and to ignite the mixture prematurely
(Fig. 20).
4 o GAS-ENGINES AND PRODUCERS
Among the parts of the piston which rapidly wear
away because constant lubrication is difficult, is the
connection with the piston-rod (Fig. 21). It is im-
portant that the bearing at the piston-pin be formed of
two parts which can be adjusted to take up the wear.
The pin itself should be of case-hardened steel. For
large engines, some manufacturers have apparently
abandoned the practice of locking the pin, by set-screws,
in flanges cast in one piece with the piston. Indeed,
the piston is often fractured by reason of the expansion
of the pins thus held on two sides. It seems advisable
FIG. 21. Piston with lubricated pin.
to secure the pin by means of a single screw in one of
the flanges, fitting it by pressure against the opposite
boss. The use of wedges or of clamping-screws, in-
troduced from without the piston to hold the pin,
should be avoided. It may happen that the wedges
will be loosened, will move out, and will grind the
cylinder, causing injuries that cannot be detected before
it is too late. The strength of the piston-pin should be
so calculated that the pressure per square inch of pro-
jected surface does not exceed 1,500 to 2,850 pounds
per square inch. It should be borne in mind that the
PISTON-RINGS 41
initial pressure of the explosion is often equal to 400 to
425 pounds per square inch. Some manufacturers
mount the pin as far to the back of the piston as possi-
ble, so as to bring it nearer the point of application of
the motive force of the explosion. Other manufac-
turers, on the other hand, mount the pin toward the
front of the piston. No great objection can be raised
against either method. In the former case the position
of the rings will limit that of the pin.
The number of these rings ought not to be less than
four or five, arranged at the rear of the piston. It is
to be observed that makers of good engines use as many
as 8 to 10 rings in the pistons of fair-sized motors.
Piston-rings of gray pig-iron can be adjusted with
the greatest nicety in such a manner that, by means
of tongues fitting in their grooves, they are held from
turning in the latter, whereby their openings are pre-
vented from registering and allowing the passage of
gas. As a general rule, a large number of rings
may be considered a distinguishing feature of a well-
built engine. In order to prevent a too rapid wear of
the cylinder, several German manufacturers finish off
the front of the piston with bronze or anti-friction
metal in engines of more than 40 to 50 horse-power. It
is to be observed, however, that this expedient is not
applicable to motors the cylinders of which are com-
paratively cold; otherwise the bronze or anti-friction
metal will deteriorate.
Arrangement of the Cylinder. The cylinder shell
or liner, in which the piston travels, and the water-
42 GAS-ENGINES AND PRODUCERS
jacket should preferably be made in separate pieces and
not cast of the same metal, in order to permit a free
expansion (Figs. 22 and 23). If for want of care or
FIG. 22. Head, jacket and liner of cylinder, cast in one piece.
of proper lubrication, which frequently occurs in gas-
engines, the cylinder should be injured by grinding,
it can be easily renewed, without the loss of all the con-
necting parts.
For the same reason, the cylinder and its casing
FIG. 23. Cylinder with independent liner and head.
should be independent of the frame. In many horizon-
tal engines, the cylinders overhang the frame through-
out the entire length, by reason of the joining of their
FAULTS OF SINGLE-ACTING ENGINES 43
front portions with the frames. Although such a con-
struction is attended with no serious consequences in
small engines, nevertheless in large engines it is ex-
ceedingly harmful. Indeed, in most modern single-
acting engines, the pistons are directly connected with
the crank-shaft by the piston-rod, without any inter-
mediate connecting-rod or cross-head. The vertical re-
FIG. 24. Single-acting engines.
action of the motive effort on the piston is, therefore,
taken up entirely by the thrust of the cylinder, which
is also vertical (Fig. 24). This thrust, acting against
an unsupported part, may cause fractures; at any rate,
it entails a rapid deterioration of the cylinder joint.
The Frame. Gas-engines driven as they are, by ex-
plosions, giving rise to shocks and blows, should be
built with frames, heavy, substantial, and broad-based,
44 GAS-ENGINES AND PRODUCERS
so as to rest solidly on the ground. This essential con-
dition is often fulfilled at the cost of the engine's ap-
pearance; but appearance will be willingly sacrificed
to meet one of the requirements of perfect operation.
For engines of more than 8 to 10 horse-power, frames
should be employed which can be secured to the
masonry foundation without a separate pedestal or base.
Some manufacturers, for the purpose of lightening the
frame, attach but little importance to the foundation
FIG. 25. Engine with inclined bearings.
and to strength of construction, and employ the design
illustrated in place of the crank-shaft bearing (Fig.
25) ; others, in order to facilitate the adjusting of the
connecting-rod bearings, prefer the second form (Fig.
26). It is evident that, in the first case, a part of the
effort produced by the explosion reacts on the upper
portion of the connecting-rod bearing, on the cap of
the crank-shaft bearing, and consequently on the fas-
tening-bolts. In the second case, if the adjustment
be not very carefully made, or if the rubbing surfaces
are insufficient, the entire thrust due to the explosion
CRANK-SHAFT BEARINGS
45
will be received by the meeting parts of the two bush-
ings, thus injuring them and causing a more rapid
wear. In the construction of large engines, some manu-
FIG. 26. Engine with straight bearings.
facturers take the precaution of forming the connect-
ing-rod bearings of four parts, adjustable to take up the
wear, so that the effort is exerted against the parts dis-
posed at right angles to each other. A form that seems
rational is that shown in Fig. 27, in which the reaction
FIG. 27. Engine with correctly designed bearings.
of the thrust is taken up by the lower bearing, rigidly
supported by the braced frame, in the direction opp'o-
site to that of the explosive effort.
46 GAS-ENGINES AND PRODUCERS
The sum of the projecting surfaces of the two bear-
ings should be so calculated that a maximum explosive
pressure of 405 to 425 pounds per square inch will not
subject the bearings to a pressure higher than 425 to
550 pounds per square inch.
Fly-Wheels. In gas-engines particularly, the fly-
wheel should be secured to the crank-shaft with the ut-
most care. It should be mounted as near as possible
to the bearings; otherwise the alinement of the shaft
will be destroyed and its strength impaired. If the fly-
wheel be fastened by means of a key or wedge having
a projecting head, it is advisable to cover the end of the
shaft by a movable sleeve. The fly-wheel should run
absolutely true and straight even if the explosion be
premature. In well-built engines the fly-wheels are
lined up and shaped to the rim. The periphery is
slightly rounded in order the better to guide the belt
\vhen applied to the wheel.
Furthermore, fly-wheels should be nicely balanced;
those are to be preferred which have no counter- weights
cast or fastened to the hub, the spokes, or the rim.
The system of balancing the engine by means of two
fly-wheels, mounted on opposite sides, is used chiefly
for the purpose of equalizing the inertia effects. Spe-
cial engines, employed for driving dynamos, and even
industrial engines of high power, are preferably fitted
with but a single fly-wheel, with an outer bearing, since
they more readily counteract the cyclic irregularities or
variations of speed occurring in a single revolution
(Fig. 28). If in this case a pulley be provided, it
FLY-WHEELS
47
J
= S -V^ Z?= ~ - " rC
<U
C
'5b
0)
I
48 GAS-ENGINES AND PRODUCERS
should be mounted between the engine and the outer
bearing. The following advantages may be cited in
favor of the single fly-wheel, particularly in the case of
dynamo-driving engines :
1. The single fly-wheel permits a more ready access
to the parts to be examined.
2. It involves the employment of a third bearing,
thus avoiding the overhang caused by two ordinary fly-
wheels.
3. It avoids the torsional strain to which the two-
wheel crank is subjected when starting, stopping, and
changing the load, the peripheral resistance varying
in one of the fly-wheels, while the other is subjected to
a strain in the opposite direction on account of the
inertia.
4. Two fly-wheels, keyed as they are to projecting
ends of the shaft, will be so affected at the rims by the
explosions that the belts will shake.
The third bearing which characterizes the single-
fly-wheel system, is but an independent support, rest-
ing solidly on the masonry bed of the engine. The
bearing with its independent support is sufficiently
rigid, and is not subjected to any stress from the crank
at the moment of explosion, the reaction of the crank
affecting only the frame bearings. With such fly-
wheels, reputable firms guarantee a cyclic regularity
which compares favorably with that of the best steam-
engines. For a duty varying from a third of the load to
the maximum load, these engines, when driving direct-
current dynamos for directly supplying an electric-
FLY-WHEEL SPOKES
49
light circuit, will insure perfect steadiness of the light;
and the effectually aperiodic measuring instruments
will not indicate fluctuations greater than 2 to 3 per
cent, of the tension or intensity of the current. The
coefficient of the variations in the speed of a single rev-
olution will thus be not far from -^Q.
Straight and Curved Spoke Fly-Wheels. The
FIG. 29. Curved spoke fly-wheel.
spokes of fly-wheels are either straight or curved. In
assembling the motor parts it too often occurs that
curved spoke fly-wheels are mounted with utter dis-
regard of the direction in which they are to turn. It
is important that curved spokes should be subjected to
compression and not to traction. Hence the fly-wheels
5 o GAS-ENGINES AND PRODUCERS
should be so mounted that the concave portions of the
spokes travel in the direction of rotation, as shown in
the accompanying diagram (Fig. 29). If a single fly-
wheel be employed on an engine of the type in which
FIG. 30. Forged crank -shafts.
the speed is governed by the " hit-and-miss " system,
the fly-wheel should be extra heavy to counteract the ir-
regularities of the motive impulses when the engine is
not working at its full load, or in other words, when no
explosion takes place at every cycle.
The Crank-Shaft. The crank-shaft should be made
of the best mild steel. Those shafts are to be preferred
_
o
FIG. 31. Correct design of crank-shaft.
the cranks of which are not forged on (Fig. 30), but
cut out of the mass of metal; furthermore, the brackets
or supports should be planed and shaped so that they
are square in cross-section.
CAMS AND ROLLERS
5 1
Such a design involves fine workmanship and speaks
well for the construction of the whole engine. More-
over, it enables the bearings to be brought nearer each
other, reduces to a minimum that part of the crank-
shaft which may be considered the weakest, and per-
mits a rational and exact counterbalancing of the mov-
ing parts, such as the crank and the end of the connect-
ing-rod. The best manufacturers have adopted the
method of fastening to the cranks balancing weights
secured to the brackets, especially for high-speed en-
IT
FIG. 32. Crank -shaft with balancing weight.
gines or for engines of high power. The projecting
surface of the crank-pin should, as a rule, be calculated
for a pressure of 1,400 pounds per square inch.
Cams, Rollers, etc. The cams, rollers, thrust-bear-
ings, as well as the piston-pin in particular, should be
made of good steel, case-hardened to a depth of at least
.08 of an inch. Their hardness and the degree of
cementation may be tested by means of a file.- This is
the method followed by the best manufacturers.
Bearings. All the bearings and all guides should
be adjustable to take up the wear. They are usually
made of bronze or of the best anti-friction metal.
52 GAS-ENGINES AND PRODUCERS
Steadiness. The steadiness of engines may be con-
sidered from two different standpoints.
I. Variation of the Number of Revolutions at Dif-
ferent Loads. This depends chiefly on the sensitive-
ness of the governor, which should be of the " inertia "
or of the " ball " (or centrifugal) type. The first form
is rarely employed, except in small engines up to 10
horse-power, and is applicable only to engines in which
FIG. 33. Inertia governor.
the " hit and miss " system is employed (Fig. 33) . The
second form is more widely used, and is applicable to
engines having " hit-and-miss " or variable admission
devices. In the first form, the governor simply displaces
a very light member, whatever may be the size of the
engine, for which reason the dimensions are very small.
In the second form, on the other hand, the governor
acts either on a conical sleeve or on some other regulat-
ing member offering resistance. Evidently, in order to
GOVERNORS
53
overcome the reactions to which it is subjected, it must
be as heavy and powerful as a steam-engine governor.
Sufficient allowance is made in a good engine for
variation in the number of revolutions between no load
and full load, not greater than two per cent, if the
admission be of the " hit-and-miss " type, and five per
cent, if it be of the variable type.
2. Cyclic Regularity. This term means simply that
the speed of the engine is constant in a single revolu-
tion. In practice this is never attained. Allowance is
made in engines used for driving direct-current dyna-
mos for a variation of about -^-; while in industrial
engines a variation of -^ is permissible. Cyclic varia-
tion depends only on the weight of the fly-wheel ;
whereas variation in the number of revolutions is deter-
mined chiefly by the governor.
Governors. Diagrams are here presented of the
principal types of governors the inertia governor, the
ball or centrifugal governor controlling an admission-
valve of the " hit-and-miss " type (Fig. 34), and the
ball or centrifugal governor controlling a variable gas-
admission valve (Fig. 35).
In distinguishing between the operation of the two
last-mentioned types, it may be stated that the former
bears the same relation to the hit-and-miss gear as it
does, for example, to the valve gear of a Corliss steam-
engine. In other words, it is an apparatus that indi-
cates without inducing, admission or cut-off. The sec-
ond type, on the other hand, operates by means of slides
and the like, as in the Ridder type of engine, in which
54 GAS-ENGINES AND PRODUCERS
it controls the displacement of the cut-off or distribu-
tion slide-valve and is subjected to variable forces, de-
pending on the pressure, lubrication, the condition of
the stuffing-boxes, and the like.
In gas as well as in steam engines, designs are to be
commended which shield the delicate mechanism from
strains and stresses that are likely to destroy its sensi-
FIG. 34. "Hit-and-miss" governor.
tiveness, as is the case in the automatic cut-off of the
Corliss steam-engine.
Governors should be provided with means to permit
the manual variation of the speed while the engine is in
operation.
For small motors, one of the most widely used ad-
mission devices is that of the " hit-and-miss " type. As
its name indicates, this admission arrangement allows
GOVERNORS 55
r.
a given quantity of gas to enter the cylinder for a num-
ber of consecutive intervals, until the engine is about
to exceed its normal speed. Thereupon the governor
cuts off the gas entirely. The result is that, in this
system, the number of admissions is variable, but that
each admitted charge is composed of a constant pro-
portion of gas and air.
The governors employed for the " hit-and-miss "
type are either " inertia " or " centrifugal " governors.
Inertia governors (Fig. 33) are less sensitive than
those of the centrifugal type. They are generally ap-
plied only to industrial engines of small power, in
which regularity of operation is a secondary considera-
tion.
Centrifugal governors employed for gas-engines
with " hit-and-miss " regulation are, as a general rule,
noteworthy for their small size, which is accounted for
by 'the fact that, in most systems, merely a movable
member is placed between the admission-controlling
means and the valve-stem (Fig. 34). It follows that
this method of operation relieves the governor of the
necessity of overcoming the resistance of the weight of
moving parts, more or less effectually lubricated, and
subjected to the reaction of the parts which they con-
trol.
In engines equipped with variable admission devices
for the gas or the explosive mixture, the governor act-
uates a sleeve on which the admission-cam is fastened
(Fig. 35). Or, the governor may displace a conical
cam, the reaction of which, on contact with the lever,
56 GAS-ENGINES AND PRODUCERS
destroys the stability of the governor. These condi-
tions justify the employment of powerful governors
which, on account of the inertia of their parts, diminish
the reactionary forces encountered.
The centrifugal governor should be sufficiently ef-
fectual to prevent variations in the number of revolu-
tions within the limits of 2 to 3 per cent, between no
load and approximately full load. Under equivalent
FIG. 35. Variable admission governor.
conditions, the inertia governor can hardly be relied
upon for a coefficient of regularity greater than 4 to
5 per cent.
The manner of a governor's operation is necessarily
dependent on the admission system adopted. And the
admission system varies essentially with the size, the
purpose of the engine, and the character of the fuel em-
ployed.
Vertical Engines. For some years past there seems
to have been a tendency in Europe to use horizontal
instead of vertical engines, especially since engines of
VERTICAL ENGINES
57
more than 10 or 15 horse-power have been extensively
used for industrial purposes. The vertical type is used
for i to 8 horse-power engines, with the cylinder in the
lower part of the frame, and the shaft and its fly-wheel
in the upper part (Fig. 36). The only merit to be
attributed to this arrangement is a great saving of space.
It is evident, however, that beyond a certain size and
power, such engines are unstable. In America particu-
FIG. 36. Vertical engine.
larly, many manufacturers of high-power engines (50
to 100 horse-power or more) prefer the vertical or
" steam-hammer " arrangement, which consists in plac-
ing the cylinder in the upper part, and the shaft in the
lower part of the frame as close to the ground as possi-
ble (Figs. 37 and 38). The problem of saving space, as
well as that of insuring stability, is thus solved, so that
it is easily possible to run up the speed of the engine.
There is also the advantage that the shaft of a dynamo
58 GAS-ENGINES AND PRODUCERS
FIG. 37. Section through an engine of the vertical or "steam -hammer" type.
MERITS OF VERTICAL ENGINES
59
can be directly coupled up with the crank-shaft of the
engine, thus dispensing with a belt, which, at the least,
0>
a
absorbs 4 to 6 per cent, of the total power. It should,
nevertheless, be borne in mind that the direct coupling
60 GAS-ENGINES AND PRODUCERS
of electric generators to engine-shafts implies the use
of extremely large and, therefore, of extremely costly
dynamos. Furthermore, by reason of this arrangement,
groups of electro-generators can be disposed in a com-
paratively small amount of space. Some English man-
ufacturers are also beginning to adopt the " steam-
hammer " type of engine for high powers, the result
being a marked saving in material and lowering of the
cost of installation.
Power of the Engine. The first thing to be con-
sidered is that the power of a gas-engine is always given
in " effective " horse-power, and that the power of a.
steam-engine is always given in " indicated " horse-
power in contracts of sale. In England and in the
United States, the expression " nominal " horse-power
is still employed. It may be advisable to define these
various terms exactly, since unscrupulous dealers, to
the buyer's loss, have done much to confuse them.
" Indicated " horse-power is a designation applied to
the theoretical power produced by the action of the
motive agent on the piston. The work performed is
measured on an indicator card, by means of which the
average pressure to be considered in the computation of
the theoretical power is ascertained.
The " effective " or brake horse-power is equal to the
" indicated " horse-power, less the energy absorbed by
passive resistance, friction of the moving parts, etc.
The " effective " work is an experimental term ap-
plied to the power actually developed at the shaft
This work is of interest solely to the engine user.
DEFINITIONS OF " POWER" 61
i 9
In a well-built motor, in which the passive resistance
by reason of the correct adjustment and simplicity of
the parts, is reduced to a minimum, the " effective "
horse-power is about 80 to 87 per cent, of the u indi-
cated " horse-power, when the engine runs under full
load. This reduced output is usually called the
" mechanical efficiency " of the engine.
" Nominal " horse-power is an arbitrary term in the
sense in which it is used in England and America,
where it is quite common. The manufacturers them-
selves do not seem to agree on its absolute value. A
" nominal " horse-power, however, is equal to anything
from 3 to 4 " effective " horse-power. The uncertainty
which ensues from the use of the term should lead to
its abandonment.
In installing a motor, the determination of its horse-
power is a matter of grave importance, which should
not be considered as if the motor were a steam-engine
or an engine of some other type. It must not be for-
gotten that, especially at full load, explosion-engines
are most efficient, and that, under these conditions, it
will generally be advisable to subordinate the utility of
having a reserve power to the economy which follows
from the employment of a motor running at a load
close to its maximum capacity. On the other hand, the
gas-engine user is unwilling to believe that the stipu-
lated horse-power of the motor which is sold -to him is
the greatest that it is capable of developing under in-
dustrial conditions. Business competition has led some
firms to sell their engines to meet these conditions. It
62 GAS-ENGINES AND PRODUCERS
is probably not stretching the truth too far to declare
that 80 per cent, of the engines sold with no exact con-
tract specifications are incapable of maintaining fo-r
more than a half hour the power which is attributed
to them, and which the buyer expects. It follows that
.the power at which the engine is sold should be both
industrially realized and maintained, if need be, for an
entire day, without the engine's showing the slightest
perturbation, or faltering in its silent and regular opera-
tion. To attain this end, it is essential that the energy
developed by the engine in normal or constant opera-
tion should not exceed 90 to 95 per cent, of the maxi-
mum power which it is able to yield, and which may be
termed its u utmost power." As a general rule,
especially for installations in which the power fluctu-
ates from the lowest possible to double this, as much
attention must be paid to the consumption at half load
as at full load; and preference should be given to the
engine which, other things being equal, will operate
most economically at its lowest load. In this case the
consumption per effective horse-power is appreciably
higher. Generally, this consumption is greater by 20
to 30 per cent, than that at full load. This is partic-
ularly true of the single-acting engines so widely used
for horse-powers less than 100 to 150.
In some double or triple-acting engines, according
to certain writers, the diminution in the consumption
will hardly be proportional to the diminution of the
power, or at any rate, the difference between the con-
sumption per B. H. P. at full load and at reduced load
ENGINE POWER 63
will be less than in other engines. It should be ob-
served, however, that this statement is apparently not
borne out by experiments which the author has had
occasion to make. To a slight degree, this economy is
obtained at the cost of simplicity, and consequently, at
the cost of the engine. At all events, the engines have
the merit of great cyclic regularity, rendering them
serviceable for driving electric-light dynamos; but this
regularity can also be attained by the use of the extra
heavy fly-wheels which English firms, in particular,
have introduced.
Automatic Starting. When the gas-engine was first
introduced, starting was effected simply by manually
turning the fly-wheel until steady running was assured.
This procedure, altogether too crude in its way, is
attended with some danger. In a few countries it is
prohibited by laws regulating the employment of in-
dustrial machinery. If the engine be of rather large
size one, moreover, which operates at high pres-
sure such a method of starting is very troublesome.
For these reasons, among others, manufacturers have
devised automatic means of setting a gas-engine in
motion.
Of such automatic devices, the first that shall be
mentioned is a combination of pipes, provided with
cocks, by the manipulation of which, a certain amount
of gas, drawn from the supply pipe, is introduced into
the engine-cylinder. The piston is first placed in a
suitable position, and behind it a mixture is formed
which is ignited by a naked flame situated near a con-
64 GAS-ENGINES AND PRODUCERS
venient orifice. When the explosion takes place the
ignition-orifice is automatically closed, and the .piston
is given its motive impulse. The engine thus started
continues to run in accordance with the regular recur-
rence of the cycles. In this system, starting is effected
by the explosion of a mixture, without previous com-
pression.
Some designers have devised a system of hand-
pumps which compress in the cylinder a mixture of
air and gas, ignited at the proper time by allowing it
to come into contact with the igniter, through the man-
ipulation of cocks (Fig. 39).
These two methods are not absolutely effective.
They require a certain deftness which can be acquired
only after some practice. Furthermore, they are ob-
jectionable because the starting is effected too violently,
and because the instantaneous explosion subjects the
stationary piston, crank, and fly-wheel to a shock so
sudden that they may be severely strained and may even
break. Moreover, the slightest leakage in one of the
valves or checks may cause the entire system to fail,
and, particularly in the case of the pump, may induce
a back explosion exceedingly dangerous to the man in
charge of the engine.
These systems are now almost generally supplanted
by the compressed-air system, which is simpler, less
dangerous, and more certain in its effect.
The elements comprising the system in question in-
clude essentially a reservoir of thick sheet iron, capable
of resisting a pressure of 180 to 225 pounds and suffi-
AUTOMATIC STARTER 65
t .
cient in capacity to start an engine several times. This
reservoir is connected with the engine by piping, which
is disposed in one of two ways, depending upon whether
FIG. 39. Tangye starter.
the reservoir is charged by the engine itself operatively
connected with the compressor, or by an independent
compressor, mechanically operated.
In the first case, the pipe is provided with a stop-
cock, mounted adjacent to the cylinder, and with a
check-valve. When the engine is started and the gas
66 GAS-ENGINES AND PRODUCERS
cut off, the air is drawn in at each cycle and driven
back into the reservoir during the period of compres-
sion. When the engine, running under these conditions
by reason of the inertia of the fly-wheel, begins to slow
down, the check-valve is closed and the gas-admission
valve opened, so as to produce several explosions and to
impart a certain speed to the engine in order to con-
tinue the charging of the reservoir with compressed air.
This done, the valve on the reservoir itself is tightly
closed, as well as the check-valve, so as to avoid any
leakage likely to cause a fall in the reservoir's pressure.
In the second case, which applies particularly to
engines of more than 50 horse-power, the charging pipe
connected with the reservoir is necessarily independent
of the pipe by means of which the motor is started.
The reservoir having been filled and the decompres-
sion cam thrown into gear, starting is accomplished :
1. By placing the piston in starting position, which
corresponds with a crank inclination of 10 to 20 degrees
in the direction of the piston's movement, from the
rear dead center, immediately after the period of com-
pression;
2. By opening the reservoir-valve;
3. By allowing the compressed air to. enter the
cylinder rapidly, through the quick manipulation of
the stop-cock, which is closed again when the impulse
is given and reopened at the corresponding period of
the following cycle, this operation being repeated sev-
eral times in order to impart sufficient speed to the
motor;
AUTOMATIC STARTERS 67
p
4. By opening the gas-valve and finally closing the
two valves of the compressed-air pipe.
The pipes and compressed-air reservoirs should be
perfectly tight. The reservoirs should have a capacity
in inverse ratio to the pressure under which they are
placed, i.e., they increase in size as the pressure de-
creases. If, for example, the reservoirs should be op-
erated normally at a pressure of 105 to 120 pounds per
square inch, their capacity should be at least five or six
times the volume of the engine-cylinder. If these res-
ervoirs are charged by the engine itself, the pressure
will always be less by 15 to 20 per cent, than that
of the compression.
CHAPTER III
THE INSTALLATION OF AN ENGINE
IN the preceding chapter the various structural de-
tails of an engine have been summarized and those ar-
rangements indicated which, from a general stand-
point, seem most commendable. No particular system
has been described in order that this manual might be
kept within proper limits. Moreover, the best-know T n
writers, such as Hutton, Hiscox, Parsell and Weed, in
America; Aime Witz, in France; Dugald Clerk, Fred-
erick Grover, and the late Bryan Donkin, in England;
Giildner, Schottler, Thering, in Germany, have pub-
lished very full descriptive works on the various types
of engines.
We shall now consider the various methods which
seem preferable in installing an engine. The directions
to be given, the author believes, have not been hitherto
published in any work, and are here formulated, after
an experience of fifteen years, acquired in testing over
400 engines of all kinds, and in studying the methods
of the 'leading gas-engine-building firms in the chief
industrial centers of Europe and America.
Location. The engine should be preferably located
in a well-lighted place, accessible for inspection and
maintenance, and should be kept entirely free from
68
GAS-PIPES 60
t y
dust. As a general rule, the engine space should be en-
closed. An engine should not be located in a cellar, on
a damp floor, or in badly illuminated and ventilated
places.
Gas-Pipes. The pipes by which fuel is conducted
to engines, driven by street-gas, and the gas-bags, etc.,
are rarely altogether free from leakage. For this
reason, the engine-room should be as well ventilated as
possible in the interest of safety. Long lines of pipe
between the meter and the engine should be avoided,
for the sake of economy, since the chances for leakage
increase with the length of the pipe. It seldom happens
that the leakage of a pipe 30 to 50 feet long, supplying
a 30 horse-power engine, is much less than 90 cubic feet
per hour. The beneficial effect of short supply pipes
between meter and engine on the running of the engine
is another point to be kept in mind.
An engine should be supplied with gas as cool as
possible, which condition is seldom realized if long
pipe lines be employed, extending through workshops,
the temperature of which is usually higher than that of
underground piping. On the other hand, pipes should
not be exposed to the freezing temperature of winter,
since the frost formed within the pipe, and particularly
the crystalline deposition of naphthaline, reduces, the
cross section and sometimes clogs the passage. Often
it happens that water condenses in the pipes; conse-
quently, the piping should be disposed so as to obviate
inclines, in which the water can collect in pockets. An
accumulation of water is usually manifested by fluctua-
7
GAS-ENGINES AND PRODUCERS
tions in the flame of the burner. In places where water
can collect, a drain-cock should be inserted. In places
exposed to frost, a cock or a plug should be provided,
so that a liquid can be introduced to dissolve the naph-
thaline. To insure the perfect operation of the engine,
as well as to avoid fluctuations in nearby lights, pipes
having a large diameter should preferably be em-
ployed. The cross-section should not be less than that
of the discharge-pipe of the meter, selected in accord-
ance with the prescriptions of the following table:
GAS-METERS.
Capacity.
Normal
hourly flow.
Dimension in inches.
Diameter
of pipe
in inches.
Power of en-
gine to be fed.
Height.
Width.
Depth.
3 burners
I4.726cu.ft.
13
II
9H
0.590
i/ a h.-p.
s ;;
24.710 "
18
i3t
I0t
0.787
3/4 "
10 "
49.420 <(
21*
18*
"A
0.984
1-2 "
20 "
98.840 "
*3A
I9H
'5 A
1.181
3-4 "
30 "
148.260 "
25i
2Mi
'8 T \
1.456
5-6 "
So "
247.100 "
29!
2 4 T V
20 T 7 5
1.592
7-10 <{
60 "
296.520 tl
3A
251
251
1.671
11-14
80 "
395-360 l>
33T 5 ir
30A
27i
1.968
iS-9 "
100 "
494.2OO '
35
33TTT
29H
1.968
20-25 "
150 "
741.300 "
4A
4&
33iJ
30-40
The records made are exact only when the meters
(Fig. 40) are installed and operated under normal con-
ditions. Two chief causes tend to falsify the measure-
ments in wet meters : ( i ) evaporation of the water, (2)
the failure to have the meter level.
Evaporation occurs incessantly,, owing to the flow-
Ing of the gas through the apparatus, and increases with
a rise in the temperature of the atmosphere surrounding
the meter. Consequently this temperature must be kept
METERS
7 1
down, for which reason the meter should be placed as
near the ground as possible. The evaporation also in-
creases with the volume of gas delivered. Hence the
meter should not supply more than the volume for
which it was intended. In order to facilitate the re-
turn of the water of condensation to the meter and to
prevent its accumulation, the pipes should be inclined
as far as possible toward the meter. The lowering of
FIG. 40. Wet gas-meter.
the water-level in the meter benefits the consumer at
the expense of the gas company.
Inclination from the horizontal has an effect that
varies with the direction of inclination. If the meter
be inclined forward, or from left to right, the water
can flow out by the lateral opening at the level, and in-
correct measurements are made to the consumer's cost.
During winter, the meter should be protected from
cold. The simplest way to accomplish this, is to wrap
substances around the meter which are poor conductors
of heat, such as straw, hay, rags, cotton, and the like.
Freezing of the water can also be prevented by the addi-
72 GAS-ENGINES AND PRODUCERS
tion of alcohol in the proportion of 2 pints per burner.
The water is thus enabled to withstand a temperature
of about 5 degrees F. below zero. Instead of alcohol,
glycerine in the same proportions can be employed,
care being taken that the glycerine is neutral, in order
FIG. 41. Dry gas-meter.
that the meter may not be attacked by the acids which
the liquid sometimes contains.
Dry Meters. Dry meters are employed chiefly in
cold climates, where wet meters could be protected only
with difficulty and where the water is likely to freeze.
In the United States the dry meter is the type most
widely employed. In Sweden and in Holland it is also
generally introduced (Fig. 41).
In the matter of accuracy of measurement there is
little, if any, difference between wet and dry meters.
The dry meter has the merit of measuring correctly re-
DRY METERS
73
gardless of the fluctuations in the water level. On the
other hand, it is open to the objection of absorbing
somewhat more pressure than the wet meter, after hav-
ing been in operation for a certain length of time.
FIG. 42. Section through a dry gas-meter.
This is an objection of no great weight; for there is
always enough pressure in the mains and pipes to
operate a meter.
In many cases, where the employment of non-freez-
ing liquids is necessary, the dry meter may be used to
74 GAS-ENGINES AND PRODUCERS
advantage, since all such liquids have more or less cor-
roding effect on sheet lead and even tin, depending
upon the composition of the gas.
The dry meter comprises two bellows, operating in
a casing divided into two compartments by a central
FIG. 43. Section through a dry gas-meter.
partition. The gas is distributed on one or the other
side of the bellows, by slides B. The slides B are pro-
vided with cranks , controlled by levers M, act-
uated by transmission shafts O, driven by the bellows.
The meter is adjusted by a screw which changes the
throw of the cranks E and consequently affects the bel-
CONSTRUCTION OF A DRY METER
75
lows. The movement of the crank-shaft D is trans-
mitted to the indicating apparatus. In order to obvi-
ate any leakage, this shaft passes through a stuffing-box,
FIG. 44. Rubber bag to prevent fluctuations of the ignition flame.
G. The diagrams (Figs. 42-43) show the construction
of a dry meter, the arrows indicating the course taken
by the gas.
Care should be taken to provide the gas-pipe with
a drain-cock, at a point near the engine. By means of
this cock, any air in the pipe can be allowed to
76 GAS-ENGINES AND PRODUCERS
FIG. 45. Rubber bags on gas-pipes.
PRESSURE-REGULATORS 77
escape before starting; otherwise the engine can be set
in motion only with difficulty. If the engine be pro-
vided with an incandescent tube, the gas-supply pipe of
the igniter should be fitted with a small rubber pouch
or bag, in order to obviate fluctuations in the burner
flame, caused by variations in the pressure (Fig. 44).
As a general rule, the supply-pipe should be connected
with the main pipe on the forward side of the bags and
gas-governors. The main pipe and all other piping
near the engine should extend underground, so that
free access to the motor from all sides can be obtained,
without possibility of injury.
Anti-pulsators , Bags , Pressure-Regulators . The
most commonly employed means of preventing fluctua-
tion of nearby lights, due to the sharp strokes of the en-
gine, consists in providing the gas-supply pipe with rub-
ber bags (Fig. 45), which form reservoirs for the gas
and, by reason of their elasticity, counteract the effect
produced by the suction of the engine. Nevertheless, in
order to insure a supply of gas at a constant pressure,
which is necessary for the perfect operation of the en-
gine, there are generally used, in addition to the bags,
devices called gas-governors, or anti-pulsators (Fig.
4 6).
Although these devices are constructed in different
ways, the underlying principle is the same in all. They
comprise a metallic casing, containing a flexible dia-
phragm of rubber or of some fabric impermeable to
gas. Suction of the engine creates a vacuum in the cas-
ing. The diaphragm bends, thereby actuating a valve,
78 GAS-ENGINES AND PRODUCERS
which cuts off the gas supply. During the three fol-
lowing periods (compression, explosion, and exhaust)
the gas, by reason of its pressure on the diaphragm,
opens the valve and fills the casing, ready for the next
suction stroke.
Other devices, which are never sold with the engine,
but are rendered necessary by reason of the conditions
imposed by the gas supply are sold under the name
FIG. 46. An anti-pulsator.
" pressure-regulators " (Fig. 47). They consist of a
bell, floating in a reservoir containing water and gly-
cerine (or mercury), and likewise actuate a valve
which partially controls the flow of gas. This valve
being balanced, its mechanical action is the more cer-
tain. Such devices are very effective in maintaining
the steadiness of lights. On the other hand, they are
often an obstacle to the operation of the engine be-
cause they reduce the flow and pressure of the gas too
much. In order to obviate this difficulty, a pressure-
regulator should be chosen with discrimination, and of
or
PRESSURE-REGULATORS
of
sufficiently large size to insure the maintenance of an
adequate supply of gas to the engine. Frequent ex-
aminations should be made to ascertain if the bell of
the regulator is immersed in the liquid. In the case of
anti-pulsators, care should be taken that they are not
spattered with oil, which has a disastrous effect on rub-
ber. Anti-pulsators are generally mounted about 4
FIG. 47. A pressure-regulator.
inches from a wall, in order that the diaphragm may
be actuated by hand, if need be.
Precautions. In order not to strain the rubber of
the bags or of the anti-pulsators, it is advisable to place
a stop-cock in advance of these devices so that they can
not be filled while the motor is at rest.
The capacity of the rubber bags that can be bought
8o GAS-ENGINES AND PRODUCERS
in the market being limited, it is necessary to place one,
two, or three extra bags in series (Figs. 48 and 49), for
large pipes; but it should be borne in mind that the
FIGS. 48-49. Arrangement of rubber bags.
total section of the branch pipes should be at least equal
to that of the main pipe. It is also advisable to extend
the tube completely through the bag as shown in Figs.
48 and 49.
If there be two branch pipes the minimum diameter
DIAMETER OF PIPES
81
which meets this requirement is ascertained as follows:
Draw to any scale a semicircle having a diameter
equal or proportional to that of the main pipe (Fig.
50) . The sides of the isosceles triangle inscribed with-
in this semicircle give the minimum diameter of each
of the branch pipes.
Sometimes engines are provided with a cock having
an arrangement by means of which the gas feed is per-
manently regulated, according to the quality and pres-
FIG. 51,
sure of the gas and according to the load at which the
engine is to run. This renders it possible to open the
cock always to the same point (Fig. 51).
Air Suction. In a special chapter the precautions to
be taken to counteract the influence of the suction of the
engine in causing vibration will be treated. The man-
ner in which the suction of air is effected necessarily
has as marked an influence on the operation of the en-
gine as the supply of gas, since air and gas constitute
the explosive mixture.
Resistance to the suction of air should be carefully
82 GAS-ENGINES AND PRODUCERS
avoided, for which reason the length of the pipe should
be reduced to a minimum, and its cross-section kept at
least equal to that of the air inlet of the engine. Since
the quality of street-gas varies with each city, the
proper proportions of gas and air are not constant. In
order that these proportions may be regulated, it is a
matter of some importance to fit some suitable device
on the pipe. Good engines are provided with a plug
or flap valve. Generally the air-pipe terminates either
in the hollowed portion of the frame, or in an inde-
pendent pot, or air chest. The first arrangement is not
to be recommended for engines over 20 to 25 horse-
power. Accidents may result, such as the breaking of
the frame by reason of back firing, of which more will
be said later. If an independent chest be employed, its
closeness to the ground renders it possible for dust
easily to pass through the air-holes in the walls at the
moment of suction, and even to enter the cylinder,
where its presence is particularly harmful, leading, as
it does, to the rapid wear of the rubbing surfaces. This
evil can be largely remedied by filling the air-chest
with cocoa fiber or even wood fiber, provided the latter
does not become packed down so as to prevent the air
from passing freely. Such fibers act as air-filters. Reg-
ular cleaning or renewal of the fiber protects the cylin-
der from wear. In a general way, care should be
taken, before fitting both the gas and air pipes, to tap
the pipes, elbows, and joints lightly with a hammer on
the outside in order to loosen whatever rust or sand
may cling to the interior; otherwise this foreign matter
MOUNTING THE AIR-PIPE 83
may enter the cylinder and cause perturbations in the
operation of the engine. Under all circumstances, care
should be taken not to place the end of the air-pipe
under the floor or in an enclosed space, because leakage
may occur, due to the bad seating of the air-valve, there-
by producing a mixture which may explode if the
flame leaps back, as we shall see in the discussion of
suction by pipes terminating in the hollow of the frame.
On the other hand, sand or saw-dust should not be
sprinkled on the floor.
Exhaust. For the exhaust, cast-iron or drawn pipes
as short as possible should be used. Not only the power
of the engine, but also its economic consumption, can be
markedly affected by the employment of long and bent
pipes. Resistance to the exhaust of the products of
combustion not only causes an injurious counter-pres-
sure, but also prevents the clearing of the cylinder of
burnt gases, which contaminate the aspired mixture
and rob it of much of its explosiveness. The necessity
of evacuating the cylinder as completely as possible is,
nevertheless, not always reconcilable with local sur-
roundings. To a certain extent, the objections to long
exhaust-pipes are overcome by rigorously avoiding the
use of elbows. Gradual curves are preferable. In the
case of very long pipes it is advisable to increase their
diameter every 16 feet from the exhaust. The exhaust-
chest should be placed as near as possible to the engine;
it should never be buried ; for the joints of the inlet and
outlet pipes of the exhaust-chest should be easily acces-
sible, so that they may be renewed when necessary. The
84 GAS-ENGINES AND PRODUCERS
author recommends the placing of the exhaust-chest in
a masonry pit, which can be closed with a sheet-metal
cover. For engines of 20 horse-power and upward,
these joints should be entirely of asbestos. Pipes
screwed directly into the casting are liable to rust. EX-
FIG. 52. Method of mounting pipes.
posed as they are to the steam or water of the exhaust,
they cannot be detached.
The water, which results from the combination of
the hydrogen of the gas with the oxygen of the air, is
deposited in most cases at the bottom of the exhaust-
chest. It is advisable to fit a plug or iron cock in the
base of the chest. Alkaline or acid water will always
corrode a bronze cock. In order that the pipes may
not also be attacked, they are not disposed horizontally,
THE EXHAUST-PIPE 85
but are given a slight incline toward the point where
the water is drained off. If pipes of some length be
employed, they should be able to expand freely with-
out straining the joints, as shown in the accompany-
ing diagram (Fig. 52), in which the exhaust-chest
rests on iron rollers which permit a slight displace-
ment.
For the sake of safety, at least that portion of the
piping which is near the engine should be located at a
proper distance from woodwork and other combustible
material. By no means should the exhaust discharge
into a sewer or chimney, even though the sewer or
chimney be not in use; for the unburnt gases may be
trapped, and dangerous explosions may ensue at the
moment of discharge.
The joints or threaded sleeves employed in assem-
bling the exhaust-pipe should be tested for tightness.
The combined action of the moisture and heat causes
the metal to rust and to deteriorate very rapidly at
leaky spots.
When several engines are installed near one another,
each should be provided with a special exhaust-pipe;
otherwise it may happen, when the engines are all
running at once, that the products of combustion dis-
charged by the one may cause a back pressure detri-
mental to the exhaust of the next.
It is possible to employ a pipe common to all the ex-
hausts if the pipe starts from a point beyond the ex-
haust-chests, in which case Y-joints and not T-joints
are to be used.
86 GAS-ENGINES AND PRODUCERS
The manner of securing the pipes to walls by means
of detachable hangers, lined with asbestos, is shown in
a general way in the accompanying Fig. 53. The
object of this arrangement is to render detachment
easy and to prevent the transmission of shocks to the
masonry.
The precautions to be taken for muffling the noise of
the exhaust will be discussed later.
The end of the exhaust-pipe should be slightly
FIG. 53. Method of securing pipes to walls.
curved down in order to prevent the entrance of rain.
Exhaust-pipes are subjected to considerable vibration,
due to the sudden discharge of the gases. To protect
the joints, the pipes should be rigidly fastened in place.
Legal Authorization. In most countries gas-en-
gines may be installed only in accordance with the
provision of general or local laws, which impose cer-
tain conditions. These laws vary with different local-
ities, for which reason they are not discussed here.
CHAPTER IV
FOUNDATION AND EXHAUST
THE reader will remember from what has already
been said that a gas-engine is a motor which, more than
any other, is subjected to forces, suddenly and re-
peatedly exerted, producing violent reactions on the
foundation. It follows that the foundation must be
made particularly resistant by properly determining its
shape and size and by carefully selecting the material
of which it is to be built.
The Foundation Materials. Well-hardened brick
should be used. The top course of bricks should be
laid on edge. It is advisable to increase the stability
of the foundation by longitudinally elongating it to-
ward the base, as shown in the accompanying diagram
( Fi g- 54)-
As a binding material, only mortar composed of
coarse'sand or river sand and of good cement, should
be used. Instead of coarse sand, crushed slag, well-
screened, may be employed. The mortar should con-
sist of 2 /$ slag and ^ cement. Oil should not in any
way come into contact with the mortar; it may perco-
late through the cement and alter its resistant qualities.
As in the construction of all foundations, care should
be taken to excavate down to good soil and to line the
87
88 GAS-ENGINES AND PRODUCERS
bottom with concrete, in order to form a single mass of
artificial stone. A day or two should be allowed for
the masonry to dry out, before filling in around it.
When the engine is installed on the ground floor
above a vaulted cellar, the foundation should not rest
FIG. 54. Method of building the foundation.
directly on the vault below or on the joists, but should
be built upon the very floor of the cellar, so that it
passes through the planking of the ground floor with-
out contact.
When the engine is to be installed on a staging, the
THE FOUNDATION
89
method of securing it in place illustrated in Fig. 55
should be adopted.
Although a foundation, built in the manner de-
scribed, will fulfill the usual conditions of an industrial
installation, it will be inadequate for special cases in
which trepidation is to be expected. Such is the case
when engines are to be installed in places where, ow-
ing to the absence of factories, it is necessary to avoid
FIG. 55. Elevated foundation.
all nuisance, such as noise, trepidations, odors, and
the like.
Vibration. In order to prevent the transmission of
vibration, the foundation should be carefully insulated
from all neighboring walls. For this purpose various
insulating substances called " anti-vibratory " are to be
recommended. Among these may be mentioned horse-
hair, felt packing, cork, and the like. The efficacy
of these substances depends much on the manner in
which they are applied. It is always advisable to inter-
pose a layer of one of these substances, from one to four
inches thick, between the foundation and the surround-
ing soil, the thickness varying with the nature of the
9 o GAS-ENGINES AND PRODUCERS
material used and the effect to be obtained. Between
the bed of concrete, mentioned previously, and the
foundation-masonry and between the foundation and
the engine-frame, a layer of insulating material may
well be placed. Preference is to be given to substances
not likely to rot or at least not likely to lose their in-
sulating property, when acted upon by heat, moisture
or pressure.
Here it may not be amiss to warn against the utiliza-
tion of cork for the bottom of the foundation ; for water
may cause the cork to swell and to dislocate the founda-
tion or destroy its level.
The employment of the various substances men-
tioned does not entail any great expense when the
foundations are not large and the engines are light.
But the cost becomes considerable when insulating ma-
terial is to be employed for the foundation of a 30 to 50
horse-power engine and upwards. For an engine of
such size the author recommends an arrangement as
simple as it is efficient, which consists in placing the
foundation of the engine in a veritable masonry basin,
the bottom of which is a bed of concrete of suitable
thickness. The foundation is so placed that the lateral
surfaces are absolutely independent of the supporting-
walls of the basin thus formed. Care should be taken
to cover the bottom with a layer of dry sand, rammed
down well, varying in thickness with each case. This
layer of sand constitutes the anti-vibratory material and
confines the trepidations of the engine to the founda-
tion.
PREVENTION OF VIBRATION 91
As a result of this arrangement, it should be ob-
served that, being unsupported laterally, the founda-
tion should be all the more resistant, for which reason
the base-area and weight should be increased' by 30 to
40 per cent. The expense entailed will be largely off-
set by saving the cost of special anti-vibratory sub-
stances. In places liable to be flooded by water, the
basin should be cemented or asphalted.
When the engine is of some size and is intended for
the driving of one or more dynamos which may them-
selves give rise to vibrations, the dynamos are secured
directly to the foundation of the engine, which is ex-
tended for that purpose, so that both machines are car-
ried solidly on a single base.
The foregoing outline should not lead the proprie-
tor of a plant to dispense with the services of experts,
whose long experience has brought home to them the
difficulties to be overcome in special cases.
It should here be stated, as a general rule, that the
bricks should be thoroughly moistened before they are
laid in order that they may grip the mortar.
After having been placed on the foundation and
roughly trimmed with respect to the transmission de-
vices, the engine is carefully leveled by means of hard-
wood wedges driven under the base. This done, the
bolts are sealed by very gradually pouring a cement
wash into the holes, and allowing it to set. When the
holes are completely filled and the bolts securely fas-
tened in place, a shallow rim, or edge of clay, or sand
is run around the cast base, so as to form a small box
92 GAS-ENGINES AND PRODUCERS
or trough, in which cement is also poured for the pur-
pose of firmly binding the engine frame and founda-
tion together. When, as in the case of electric-light
engines, single extra-heavy fly-wheels are employed,
provided with bearings held in independent cast sup-
ports, the following rule should be observed to prevent
the overheating due to unlevelness, which usually oc-
curs at the bushings of these bearings : That part of the
foundation which is to receive such a support should
rest directly on the concrete bed and should be rigidly
connected at the bottom with the main foundation.
When the foundation is completely blocked up, the fly-
wheel bearing with its support is hung to the crank-
shaft; and not until this is effected is the masonry at
the base of the support completed and rigidly fixed in
its proper position.
For very large engines, the foundation-bolts should
be particularly well sealed into the foundation. In
order to attain this end the bricks are laid around the
bolt-holes, alternately projected and retracted as show r n
in Fig. 54. Broken stone is then rammed down around
the fixed bolt; in the interstices cement wash is poured.
Air Vibration, etc. Vibration % due chiefly to the
transmission of noises and the displacement of air by
the piston should not be confused with the trepidations
previously mentioned.
The noise of an engine is caused by two dis-
tinct phenomena. The one is due to the transmit-
ting properties of the entire solid mass constituting
the frame, the foundation, and the soil. The other is
AIR VIBRATION
93
due to vibrations transmitted to the air. In both cases,
in order to reduce the noise to a minimum, the moving
parts should be kept nicely adjusted, and above all,
shocks avoided, the more harmful of which are caused
by the play between the joint at the foot of the connect-
ing-rod and the piston-pin, and between the head of the
connecting-rod and the crank-shaft.
Although smooth running of the engine may be as-
sured, there is always an inherent drawback in the
rapid reciprocating movement of the piston. In large,
single-acting gas-engines, a considerable displacement
of air is thus produced. In the case of a forty horse-
power engine having a cylinder diameter and piston-
stroke respectively of 13% inches and 2i3/ 5 inches, it
is evident that at each stroke the piston will displace
about 2 cubic feet of air, the effect of which will be
doubled when it is considered that on the forward
stroke back pressure is created and on the return stroke
suction is produced.
The air motion caused by the engine is the more
readily felt as the engine-room is smaller. If the room,
for example, be 9 feet by 75 feet by 8 feet, the volume
will be i, 080 cubic feet. From this it follows that the
2 cubic feet of air in the case supposed will be alter-
nately displaced six times each second, which means
the. displacement of 12 cubic feet at short intervals
with' an average speed of 550 feet per minute. Such
vibrations transmitted to halls or neighboring rooms
are due entirely. to the displacement of the air.
In installations where the air-intake of the engine is
94 GAS-ENGINES AND PRODUCERS
located in the engine-room, a certain compensation is
secured, at the period of suction, between the quantity
of air expelled on the forward stroke of the piston and
the quantity of air drawn into the cylinder. From this
it follows that the vibration caused by the movement
of the air is felt less and occurs but once for two revolu-
tions of the engine.
This phenomenon is very manifest in narrow rooms
in which the engine happens to be installed near glass
windows. By reason of the elasticity of the glass, the
windows acquire a vibratory movement corresponding
in period with half the number of revolutions of the
engine. It follows from the preceding that, in order to
do away with the air vibration occasioned by the piston
in drawing in and forcing out air in an enclosed space,
openings should be provided for the entrance of large
quantities of air, or a sufficient supply of air should
be forced in by means of a fan.
The author ends this section with the advice that all
*
pipes in general and the exhaust-pipe in particular be
insulated from the foundation and from the walls
through which they pass as well as from the ground,
as metal pipes are good conductors of sound and liable
to carry to some distance from the engine the sounds
of the moving parts.
Exhaust Noises. Among the most difficult noises to
muffle is that of the exhaust. Indeed, it is the exhaust
above all that betrays the gas-engine by its discharge to
the exterior through the exhaust-pipe. The most com-
monly employed means for rendering the exhaust less
THE EXHAUST-MUFFLER
95
perceptible consists in extending the pipe upward as
far as possible, even to the height of the roof. This is
an easy way out of the difficulty; but it has a bad effect
on the operation of the engine. It reduces the power
generated and increases the consumption, as will be ex-
plained in a special paragraph.
Expansion-boxes, more commonly called exhaust-
mufflers, considerably deaden the noise of explosion by
FIG. 56. Exhaust-muffler.
the use of two or three successive receptacles. But this
remedy is attended with the same faults that mark the
use of extremely long pipes. The best plan is to mount
a single exhaust-muffler near the discharge of the en-
gine in the engine-room itself, where it will serve at
least the purpose of localizing the sound.
The employment of pipes of sufficiently large cross-
section to constitute expansion-boxes in themselves will
also muffle the exhaust. A more complete solution of
the problem is obtained by causing the exhaust-pipe,
96 GAS-ENGINES AND PRODUCERS
after leaving the muffler, to discharge into a masonry
trough having a volume equal to twelve times that of
the engine-cylinder (Fig. 56). This trough should
be divided into two parts, separated by a horizontal
iron grating. Into the lower part, which is empty, the
exhaust-pipe discharges; in the upper part, paving-
blocks or hard stones not likely to crumble with the
heat, are placed. Between this layer of stones and the
cover it is advisable to leave a space equal to the first.
Here the gases may expand after having been divided
into many parts in passing through the spaces left be-
tween adjacent stones. The trough should not be
closed by a rigid cover; for, although efficient muffling
may be attained, certain disadvantages are neverthe-
less encountered. It may happen that in a badly regu-
lated engine, unburnt gases may be discharged into this
trough, forming an explosive mixture which will be
ignited by the next explosion, causing considerable
damage. Still, the explosion will be less dangerous
than noisy. It may be mentioned in passing that this
disadvantage occurs rarely.
A second arrangement consists in superposing the
end of the exhaust-pipe upon a casing of suitable size,
which casing is partitioned off by several perforated
baffle-plates. This casing is preferably made of wood,
lined with metal, so that it will not be resonant. The
size of the casing, the number of partitions and their
perforations, and the manner of disposing the parti-
tions have much to do with the result to be obtained.
Here again the experience of the expert is of use.
THE EXHAUST-MUFFLER
97
Various other systems are employed, depending upon
the particular circumstances of each case. Among
these systems may be mentioned those in which the pipe
is forked at its end to form either a yoke (Fig. 57) or
a double curve, each branch of which terminates in a
muffler (Fig. 58).
It should be observed that, under ordinary conditions,
noises heard as hissing sounds are often due to the
Two types of exhaust-mufflers.
presence of projections, or to distortion of the pipes
near the discharge opening. Consequently, in connect-
ing the pipes, care should be taken that the joints or
seams have no interior projections. Occasionally,
water may be injected into the exhaust-muffler in order
to condense the vapors of the exhaust, the result being
a deadening of the noises; but in order to be truly effi-
cient this method should be employed with discretion,
for which reason the advice of an expert is of value.
CHAPTER V
WATER CIRCULATION
CIRCULATION of water in explosion-engines is one of
the essentials of their perfect operation. Two special
cases are encountered. In the one the jacket of the en-
gine is supplied with running water; in the other, reser-
voirs are employed, the circulation being effected
simply by the difference in specific gravity in a thermo-
siphon apparatus. Coolers are also used.
Running Water. A water-jacket fed from a con-
stant source of running water, such as the water mains
of a town, is certainly productive of the best results, the
supply, moreover, being easily regulated; but the sys-
tem is not widely used because the water runs away and,
is entirely lost. If running water be employed, the out-
let of trie jacket is so disposed that the water gushes out
immediately on leaving the cylinder, and that the flow
is visible and accessible, in order that the temperature
may be tested by the hand. Apart from the relatively
great cost of water in towns, the use of running water
is objectionable on account of its chemical composi-
tion. Though it may be clear and limpid, it frequently
contains lime salts, carbonates, sulphates, and silicates
which are precipitated by reason of the sudden change
of temperature to which the water is subjected as .it
9 8
IMPURE WATER 99
comes into contact with the walls of the cylinder. That
part of the water-jacket surrounding the head or explo-
sion-chamber, where the temperature is necessarily the
highest, becomes literally covered with calcareous in-
crustations, which are the more harmful because they
are bad conductors of heat and because they reduce and
even obs.truct the passage exactly at the point where the
water must circulate most freely to do any good. If the
circulating water be pumped into the jacket, it is pref-
erable, wherever possible, to use cistern water, which is
not likely to contain lime salts in suspension. If river
water be used, it should be free from the objections
already mentioned, which are all the more grave if the
water be muddy, as sometimes happens. The water-
jacket can be easily freed from all non-adhering de-
posits by flushing it periodically through the medium
of a conveniently placed cock. It is always preferable
to pass the water through a reservoir where its impuri-
ties can settle, before it flows to the cylinder. In the
case considered, the water usually has an average tem-
perature of 54 to 60 degrees F., under which condition
the hourly flow should be at least $y 2 gallons per horse-
power per hour, the temperature rising at the outlet-
pipe of the cylinder to 140 and 158 degrees F., which
should not be surpassed. However, in engines working
with high compression, 104 to 122 degrees F. should
not be exceeded.
If the water-jacket be fed by a reservoir, it is essen-
tial that the reservoir comply with the following con-
ditions:
ioo GAS-ENGINES AND PRODUCERS
In horizontal engines the water-inlet is always
located in the base of the cylinder, while the outlet is
located at the top. By providing the inlet-pipe extend-
ing to the cylinder with a cock, the circulation of water
can be regulated to correspond with the work per-
formed by the engine. Another cock at the end of the
outlet-pipe near the reservoir serves, in conjunction
FIG. 59. Thermo -syphon cooling system.
with the first, to arrest the circulating water. When the
weather is very cold or when the cylinder must be
repaired, these two cocks may be closed, and the pipe
and water-jacket of the cylinder drained by means of
the drain-cock V (Fig. 59), mounted at the inlet of the
engine's water-jacket. In order that the pressure of
the atmosphere may not prevent the flowing of the
water, the highest part of the pipe is provided with a
small tube, T, communicating with the atmosphere.
On account of the importance of preventing, losses
WATER-TANKS
101
of the charge in the pipes the author recommends the
utilization of sluice-valves of the type shown in Fig.
60, instead of the usual cone or plug type.
FIG. 60. Vanne sluice-cock.
Water-Tanks. The reservoir is mounted in such a
way that its base is flush with the top of the cylinder; it
should be as near as possible to the cylinder in order to
obviate the use of long inlet and return pipes. This
fact, however, does not necessarily render it advisable
to place the reservoir in the engine-room; for such a
disposition is doubly disadvantageous in so far as it
does not permit a sufficiently rapid cooling of the cir-
culating water by reason of the high temperature of the
102 GAS-ENGINES AND PRODUCERS
surrounding air, and in so far as it is liable to cause the
formation of vapors which injuriously affect the en-
gine. Consequently, the reservoir should be placed in
as cool a place as possible, preferably even in the open
air; for the water is not likely to freeze, except when
it has been allowed to stand for a considerable time.
The reservoir should be left uncovered so as to facili-
tate cooling by the liberation of the vapors formed on
the surface of the water.
Circulation being effected solely by the difference
in specific gravity or density between the warmer water
emerging from the cylinder and the cooler water which
flows in from the reservoir, the slightest obstruction
will impede the flow. Hence, the cross-section of the
pipes should not be less than that of the inlet and outlet
openings of the cylinder of the engine. Good circula-
tion cannot be attained if the water must overcome in-
clines or obstacles in the pipes themselves. Instead of
elbows, long curves of great radius, limited to the
smallest possible number, should be employed. This is
particularly true of the return-pipe extending from
the cylinder back to the reservoir. For this pipe a
minimum incline of 10 to 15 per cent, should be al-
lowed, in order that the water may run up into the
reservoir. The height of the water in the reservoir
should be from 2 to 4 inches above the discharge of the
return-pipe. In order to maintain this level it is advis-
able to use some automatic device such as a float-valve,
in which case the reservoir should not be allowed to
become too full.
WATER-TANKS
103
The size of a reservoir is determined by the engine;
it should be large enough to enable the engine to run
FIG. 61. Correct arrangement of tanks and piping.
smoothly at its maximum load for several hours con-
secutively. Under these conditions, the reservoir
104 GAS-ENGINES AND PRODUCERS
should have a capacity of 45 to 55 gallons per horse-
power for engines with " hit-and-miss " admission, and
55 to 65 gallons for engines controlled by variable ad-
mission. It is not advisable to employ reservoirs hav-
FiG. 62. Incorrect arrangement of tanks and piping.
ing a capacity of more than 330 to 440 gallons, the
usual diameter being about 3 feet.
If the power of the engine be such that several
reservoirs are necessary, then the reservoirs should be
connected in such a manner that the top of the first
communicates with the bottom of the next and so on,
CONNECTION OF TANKS 105
the first reservoir receiving the water as it comes from
the cylinder (Fig. 61).
Intercommunication of the reservoirs by means of a
common top tube (a) is objectionable; and simul-
taneous intercommunication at top and bottom (a and
b) is ineffective, so far as one of the reservoirs is con-
cerned (Fig. 62) .
The reservoirs are true thermo-siphons. Conse-
quently the water should be methodically circulated;
in other words, the hottest water, flowing from the en-
FIG. 63. Tanks connected by inclined pipes.
gine into the top of the first reservoir and having, for
example, a temperature of 104 degrees F., is cooled off
to 86 degrees F. and drops to the bottom of the reser-
voir, thence to be driven, at a temperature sensibly
106 GAS-ENGINES AND PRODUCERS
equal to 86 degrees F., to the second reservoir, where a
further cooling of 18 degrees F. takes place. In pass-
ing on to the following reservoirs the temperature is
still further lowered, until the water finally reaches its
minimum temperature, after which it flows back to the
engine-cylinder.
In order to effect this cooling, the reservoirs can be
connected in several ways. The most common method,
as shown in Fig. 63, consists in connecting the reser-
voirs by oblique pipes. This is open to criticism, how-
FiG. 64. Circulating pump with by-pass.
ever, since leakage occurs, caused by the employment
of elbows which retard the circulation. A less cum-
brous and more efficient method of connection consists
in joining the reservoirs by a single pipe at the top, as
shown in Fig. 61 ; but care must be taken to extend this
pipe at the point of its entrance into the adjoining
reservoir by means of a downwardly projecting exten-
sion, or to fit its discharge-end with a box, closed by a
single partition, open at the bottom.
PREVENTION OF INCRUSTATION 107
In order to prevent incrustation of the water-jacket
surrounding the cylinder, a pound of soda per 17 cubic
feet of the reservoir capacity is monthly introduced,
and the jacket flushed weekly by a cock conveniently
mounted near the cylinder (Fig. 59). The jacket is
thus purged of calcareous sediments, which are pre-
vented by the soda from adhering to the metal. The
flushing-cock mentioned also serves to drain the water-
jacket of the cylinder in case of intense or persistent
cold, which would certainly freeze the water in the
jacket, thereby cracking the cylinder or the exposed
pipes.
In order to regulate the circulation of the water in
accordance with the work performed by the engine, a
cock should be fitted to the water supply pipe at a con-
venient place.
In engines of large size, driven at full load for long
periods, cooling by natural circulation is often in-
adequate. In such cases, circulation is quickened by a
small rotary or reciprocating pump, driven from the
engine itself and fitted with a by-pass provided with a
cock. This arrangement permits the renewal of the
natural thermo-siphon circulation in case of accident
to the pump (Fig. 64).
Coolers. The arrangement which is illustrated in
Fig. 65, and which has the merit of simplicity, will be
found of service in cooling the water. It comprises a
tank B surmounted by a set of trays E, formed of frames
to which iron rods are secured, spaced i to 2 feet apart,
so as to form superimposed series separated by ij4 to
io8 GAS-ENGINES AND PRODUCERS
2 1 /; feet. On these trays bundles of tree branches are
placed. The cold water at the bottom of the tank is
forced by the pump P into the water-jacket, from
which it emerges hot, and flows through the pipe T y
FIG. 65. Water-cooler in which tree branches are employed.
which ends in a sprinkler G, formed of communicat-
ing tubes and perforated with a sufficient number of
holes to enable the water to fall upon the trays in many
drops. Thus finely divided, the water falls from one
tray to another, retarded as it descends by the bundles
COOLERS
109
of tree branches. It finally reaches the tank in a very
cold condition and is then ready to be pumped to the
engine. Birch branches are to be preferred on account
of their tenuity.
Great care should be taken to cover the tank with
a sheet-metal closure in order to prevent twigs and
FIG. 66. Fan-cooler.
foreign bodies from entering and from being drawn
into the pump.
In the following table the dimensions of an operative
apparatus of this kind are given, an apparatus, more-
over, that may be constructed of wood or of iron:
T~nlr
Horse-
Volume in
Height of
Pump Capacity
power.
cubic ft.
Case.
Height.
trav-base.
in gals, per min.
30
105
4-9' x 4-9'
4.4'
6.6'
16.71
40
154
5.2' x 5.2'
5.6'
7-4'
18.69
50
190
5.7' x 5.7'
6.4'
8.1'
21.99
75
350
6.6' x 6.6'
8.1'
9.1'
100
490
7.4' x 7.4'
9.1'
9.1'
43-98
no GAS-ENGINES AND PRODUCERS
In order that the water may not drop to one side, the
base of the apparatus should be made 10 to 12 inches
less in width than the tank.
The size of these apparatus may be considerably re-
duced by constructing them in the form of closed chests,
into the bottom of which air may.be injected by means
of fans in order to accelerate cooling (Fig. 66).
CHAPTER VI
LUBRICATION
LUBRICATION is a subject that should be studied by
every gas-engine user. So far as the piston is con-
cerned it is a matter of the utmost importance. The
piston does its work under very peculiar conditions.
It is driven at great linear velocities; and it is, more-
over, subjected to high temperatures which have noth-
ing in common with good lubrication if care be not
exercised.
The piston is the essential, vital element of an en-
gine. Upon its freedom from leakage depends the
maintenance of a proper compression, and, conse-
quently, the production of power and economical con-
sumption. As it travels forward and as it recedes from
the explosion-chamber, it uncovers more and more of
the frictional surface constituting the interior wall of
the cylinder. This surface, as a result, is regularly
brought into contact with the ignited, expanding gases
after each explosion. For this reason the oil which
covers the wall is constantly subjected to high tempera-
tures, by which it is likely to be volatilized and burned.
Therefore, the first condition to be fulfilled in properly
lubricating the piston is a constant and regular sup-
ply of oil.
TIT
ii2 GAS-ENGINES AND PRODUCERS
Quality of Oils. For cylinder lubrication only the
very best oils should be used; perfect lubrication is of
such importance that cost should not be considered.
Besides, the surplus oil which is usually caught in the
drip-pan is by no means lost. After having been fil-
tered it can be used for lubricating the bearings of the
crank, the cam-shaft, and like parts.
Cylinder-oil should be exceedingly pure, free from
acids, and composed of hydrocarbons that leave no resi-
due after combustion. Only mineral oils, therefore,
are suitable for the purpose. Those oils should be
selected which, with a maximum of viscosity, are
capable of withstanding great heat without volatilizing
or burning. The point at which a good cylinder-oil
ignites should not be lower than 535 degrees F.
Whether an oil possesses this essential quality is
easily enough ascertained in practice without resort-
ing to laboratory tests. All that is necessary is to heat
the oil in a metal vessel or a porcelain dish. In order
that the temperature may be uniform the vessel is
shielded from the direct flame by interposing a piece
of sheet metal or a layer of dry sand. As soon as gases
begin to arise a lighted match is held over the oil.
When the gases are ignited the thermometer reading is
taken, the instrument being immersed in the oil. The
temperature recorded is that corresponding with the
point of ignition.
For cylinder lubrication American mineral oil is
preferable to Russian oil. The specific gravity should
lie somewhere between .886 and .889 at 70 degrees F.
CYLINDER-OILS
M-3
Oil of this quality begins to evaporate at about 365
degrees F. Ignition occurs at 535 degrees F. The
point of complete combustibility lies between 625 and
645 degrees F. Oil of this quality solidifies at 39 or
41 degrees F. Its color is a reddish yellow with a
greenish fluorescence. Compared with water its degree
of viscosity lies between 11.5 and 12.5 at a tempera-
ture of 140 degrees F.
Before lubricating other parts of the engine with
oil that has been used for the piston, heavy particles
and foreign matter, such as dust, bearing incrusta-
tions, and the like, should be filtered out. The piston-
pivot and the connecting-rod head are preferably
lubricated with fresh oil, because their constant move-
ment renders inspection difficult and the control of
lubrication irksome. A good, industrial mineral oil
of usual market quality will be found satisfactory.
In order to bring home the importance of employ-
ing good cylinder-oil and of proper lubrication the
author can only state that in his personal experience he
has frequently detected losses varying from 10 to 15
per cent, in the power developed by engines poorly
lubricated.
Types of Lubricators. Among the more common
apparatus employed for automatically lubricating the
cylinder, the author mentions an English oiler of the
type pictured in Fig. 67 which is driven simply by
a belt from the intermediary shaft, and which rotates
the pulley P secured on the shaft a of the apparatus,
at a very slow speed. The shaft a is provided at its
n 4 GAS-ENGINES AND PRODUCERS
end with a small crank, from which a small iron arm
/ is suspended, which arm dips in the oil contained in
the cup G of the oiler. When the shaft a is turned this
arm, as it sweeps through the oil-bath, collects a certain
quantity of oil which it deposits on the collector
b. From this spindle the oil passes through an out-
let-pipe opening into the bottom of the oiler, and
thence to the cylinder. The entire apparatus is closed
FIG. 67. An automatic English oiler.
i
by a cover D which can be easily removed in order to
ascertain the quantity of oil still remaining in the
apparatus. Many other systems are utilized which,
like the one that has been described, enable the feed to
be controlled. Often small force-pumps are employed
as cylinder-lubricators. Whatever may be the type
selected, preference should be given to that in which
the feed is visible (Fig. 68).
If the oil be fed under pressure the cylinder is more
constantly lubricated. Pressure-lubricators are nowa-
days widely used on large engines. It is advisable to
OIL-PUMPS ii r
f j
add a little salt to the water contained in sight-feed
lubricators so that the drop of oil is easily freed.
These oil-pumps are provided with small check-
valves at their outlets as well as at the inlets of cylin-
ders. In order that pressure-lubricators may operate
perfectly they should be regularly inspected and the
check-valves ground from time to time.
The lubrication of the crank-shaft and of the two
connecting-rod heads should receive every attention.
FIG. 68. Sight-feed lubricating-pump.
Lubricating devices should be employed which,
besides being efficient, do not necessitate the stopping
of the engine in order to oil the bearings. The foot of
the connecting-rod at the point where it is pivoted to
the piston is generally lubricated with cylinder-oil
which is supplied by a tube mounted in the proper
place across the piston-wall (Fig. 69). This ar-
rangement may be adequate enough for small engines;
but it is not sufficiently sure for engines of considerable
size. An independent lubricating system should be
employed, lubrication being effected either by a
n6 GAS-ENGINES AND PRODUCERS
splasher mounted in front of the cylinder or by a lubri-
cator secured to the connecting-rod by which the pivot
is lubricated through the medium of a small tube sup-
plying special oil (Fig. 21). The head of the con-
necting-rod where it meets the crank, must also be
carefully lubricated because of the important nature
of the work which it must perform, and because of the
shocks to which it is subjected at each explosion. For
FIG. 69. Method of oiling the. piston and end of the connecting-rod.
motors of high power the system which seems to give
most satisfactory results is that illustrated in Fig. 70.
The arrangement there shown consists of an annular
vessel secured at one side of the crank and turning con-
centrically on its axis ; the vessel being connected with a
long tube extending into a channel formed in the crank
and discharging at the surface of the crank-pin within
the bearing at the head of the connecting-rod. An
adjustable sight-feed lubricator conducts the oil along
a pipe to the vessel. Turning with the shaft, the ves-
CRANK-SHAFT LUBRICATION 117
sel retains the oil in the periphery so that the feed in
the previously mentioned channel in the connecting-
rod head, is constant.
The main crank-shaft bearings are more easily lubri-
cated. Among the systems commonly used with good
results may be mentioned that shown in Fig. 71, in
which the half section represents a small tube starting
FIG. 70. Method of oiling the crank-shaft.
from the bearing and terminating in the interior of an
oil recess or reservoir cast integrally with the bearing-
cap. This reservoir is filled up to the level of the tube
opening. A piece of cotton waste held on a small iron
wire is inserted in the tube, part of the cotton being
allowed to hang down in the reservoir. This cotton
serves as a kind of siphon and feeds the bearing by
capillary attraction with a constant quantity of oil, the
supply being regulated by varying the thickness of the
n8 GAS-ENGINES AND PRODUCERS
cotton. When the motor is stopped, the cotton should
be removed in order that oil-feeding may not use-
lessly continue. Glass, sight-feed lubricators with
stop-cocks, are very often used on crank-shafts. They
are cleaner and much more easily regulated. Of all
shaft-bearing lubricators, those which are most to be
recommended are of the revolving- ring type (Fig.
72). They presuppose, however, bearings of large
FIG. 71. Cotton-waste lubricator.
size and a special arrangement of bushings which ren-
ders their application somewhat expensive. Further-
more, the revolving-ring system can hardly be used in
connection with engines of less than 20 horse-power.
Since the system is applied almost exclusively to
dynamo-shafts, it need not here be described in detail.
As its name indicates, it consists of a metal ring having
a diameter larger than that part of the shaft from
which it is suspended and by which it is rotated. The
lower part of the ring is immersed in an oil bath so
REVOLVING-RING OILERS
119
that a certain quantity of lubricant is continually trans-
ferred to the shaft.
The revolving ring bearing should be fitted with a
drain-cock and a glass tube in order to control the
level of the oil in the bearing.
Many manufacturers have adopted lubricating de-
FIG. 72. Ring type of bearing oiler.
vices for valve-stems, and especially for exhaust-valves.
The system adopted consists of a small tube curved in
any convenient direction and discharging in the stem-
guide. The free end is provided with a plug. A few
drops of petroleum are introduced once or twice a day.
The lubrication of an engine entails certain difficul-
ties which are easily overcome. One of these is the
120 GAS-ENGINES AND PRODUCERS
splashing of oil by the connecting-rod head. In order
that this splashed oil may be collected in the base
of the engine a suitably curved sheet-metal guard is
mounted over the crank. A more serious difficulty
is presented when the oil from a crank-bearing finds
its way to the hub of the fly-wheel, whence it is driven
by the centrifugal force to the rim. The oil is not only
splashed against the walls of the engine-room, but it
also destroys the adhesion of the belt if the fly-wheel
FIG. 73. Shaft with oil-guard.
be employed as a pulley. In order to overcome this
objection the oil is prevented from spreading along the
shaft by means of a circular guard (Fig. 73) mounted
on that portion of the shaft toward the interior of the
bearing.
The problem of lubrication is of particular im-
portance if the engine is driven for several days at
a time without a stop. This happens in the case of
mill and shop engines. Lubricators of large volume
or lubricators which can be readily filled without stop-
ping the engine should be employed.
CHAPTER VII
THE CONDITIONS OF PERFECT OPERATION
General Care. Gas-engines, as well as most ma-
chines in general, should be kept in perfect condition.
Cleanliness, even in the case of parts of secondary im-
portance, is indispensable. Unpainted and polished
surfaces such as the shaft of the engine, the distribut-
ing cam-shafts, the levers, the connecting-rod and the
like, should be kept in a condition equal to that when
they were new. The absence of all traces of rust or
corrosion in these parts affords sufficient evidence of
the care taken of the invisible members such as the
piston, the valves, ignition devices, and the like.
Lubrication. The rubbing surfaces of a gas-engine
should be regularly and perfectly lubricated. The
absence of lost motion and backlash in the bearings,
guides, and joints is of particular importance not only
because of its influence on steady and silent running,
but also on the power developed and on the consump-
tion. As we have already seen in the chapter on lubri-
cation, a special quality of oil should be employed *for
the lubrication of the cylinder. The feed of the lubri-
cator supplying this most vital part of the engine is so
regulated that it meets the actual requirements with
the utmost nicety possible. In a subsequent chapter,
121
122 GAS-ENGINES AND PRODUCERS
in which faulty operation will be discussed, it will be
shown how too much and too little oil may cause seri-
ous trouble.
Tightness of the Cylinder. The amount of power
developed depends principally on the degree of com-
pression to which the explosive mixture is subjected.
The economical operation of the engine depends in
general upon perfect compression. It is, therefore,
necessary to keep those parts in good order upon which
the tightness of the cylinder depends. These parts are
the piston, the valves, and their joints, and the igni-
tion devices whether they be of the hot-tube or elec-
trical variety. In order to prevent leakage at the pis-
ton, the rings should be protected from all wear. It
is of the utmost importance that the surfaces both of
the piston and of the cylinder, be highly polished so
that binding cannot occur. In cleansing the cylinder,
emery paper or abrasive powder should not be em-
ployed; for the slightest particle of abrasive between
the surfaces in contact will surely cause leakage. The
oil and dirt, which is turned black by friction and
which may adhere to the piston rings, should be
washed away with petroleum. Similarly the other
parts of the cylinder should be cleaned to which burnt
oil tends to adhere.
Valve-Regrinding. The valves should be regu-
larly ground. Even in special cases where they may
show no trace of rapid wear they should be removed
at least every month. In order to avoid any accident,
care should be taken in adjusting the valves after the
RA7T
or T M e
UNIVERSITY
VALVE-GRINDING
cap has been unbolted not to introduce a candle or a
lighted match either in the valve-chambers or in the
cylinder, without first closing the gas-cock. Further-
more, a few turns should be given to the engine, in
order to drive out any explosive mixture that may still
remain in the cylinder or the connected passages. The
exhaust-valve, by reason of the high temperature to
which the disk and the seat are subjected, should re-
ceive special attention. The valve should be ground
on its seat every two or three months at least, depend-
ing upon the load of the engine.
Bearings and Crosshead. The bushings of the en-
gine shaft should always be held tightly in place. The
looseness to which they are liable, particularly in gas-
engines on account of the sharp explosions, tends to
unscrew the nuts and to hasten the wear of the brass,
which is the result of frequent tightening. The slight-
est play in the bearings of the engine-shaft as well as
in the bearings of connecting-rods increases the sound
that engines naturally produce.
Governor. The governor should receive careful at-
tention so far as its cleanliness is concerned; for if its
operation is not easy it is apt to become " lazy " and
to lose its sensitiveness. If the governor be of the ball
type, or of the conical pendulum type operated by
centrifugal force, it is well to lubricate each joint with-
out excess of oil. In order to prevent the accumula-
tion and the solidification of oil, the governor should
be lubricated from time to time with petroleum. If
the governor is actuated by inertia, which is the case
124 GAS-ENGINES AND PRODUCERS
in most engines of the hit-and-miss variety, it needs
less care; still, it is advisable to keep the contact at
which the thrust takes place well oiled.
The operation of any of these governors is usually
controlled by the tension of a spring, or by a counter-
weight. In order to increase the speed of the engine,
or in other words, to increase the number of admissions
of gas in a given time, all that is usually necessary is
to tighten up the spring, or to change the position of
the counterweight. It should be possible to effect
this adjustment while the engine is running in such a
manner that the speed can be easily changed.
Joints. In most well-built engines the caps of the
valve-chests and other removable parts are secured
" metal on metal " without interposing special joints.
In other words, the surfaces are themselves sufficiently
cohesive to insure perfect tightness. In engines which
are not of this class, asbestos joints are very frequently
employed, particularly at the exhaust-valve cap and
the suction-valve.
In some engines, where for any reason it is necessary
frequently to detach the caps, certain precautions should
be taken to protect the joints so that they may not be
exposed to deterioration whenever they are removed.
For this purpose, they are first immersed in water in
order to be softened, then dried and washed with olive
or linseed oil on the side upon which they rest in the
engine. On the cap side they are dusted with talcum
or with graphite. Treated in this manner, the joint
will adhere on one side and will be easily released on
TEMPERATURE OF THE WATER 125
the other. Joints that are liable to come in contact
with the gases in the explosion-chamber should be free
from all projections toward the interior of the cylin-
der; for during compression these uncooled projections
may become incandescent and may thus cause prema-
ture ignition. As a general rule when the cap is
placed in position the joint should be retightened after
a certain time, when the surfaces have become suffi-
ciently heated. In order to tighten the joints the bolts
and nuts should not be oiled; otherwise the removal of
the cap becomes difficult.
Water Circulation. In a previous chapter, the im-
portance of the water circulation and the necessity of
keeping the cylinder-jacket hot, have been sufficiently
dwelt upon. As the cylinder tends to become hotter
with an increase in the load, because of the greater fre-
quency of explosions, it is advisable to regulate the
flow of the water in order to prevent its becoming more
than sufficient in quantity when the engine is lightly
loaded; for under these conditions the cylinder will be
cold and the explosive mixture will be badly utilized.
A suitable temperature of 140 to 158 degrees F. is
easily maintained by adjusting the circulation of the
water. This can be accomplished by providing the
water-inlet pipe leading to the cylinder with a cock
which can be opened more or less, as may be necessary.
The temperature of 140 to 158 degrees F. which has
been mentioned may, at first blush, seem rather high,
because it would be impossible to keep the hand on the
outlet-pipe. The cylinder, however, will not become
126 GAS-ENGINES AND PRODUCERS
overheated so long as it is possible to hold the hand
beneath the jacket near the water-inlet. This relates
only to engines having a compression of 50 to 100 Ibs.
per square inch. For engines of higher compression,
a lower running temperature will be safer. On this
matter the instructions of the engine maker should be
carried out.
Adjustment. Gas-engines, at least those which are
built by trustworthy firms, are always put to the brake
test before they are sent from the shops, and are ad-
justed to meet the requirements of maximum efficiency.
But since the nature and quality of gas necessarily
vary with each city, it is evident that an engine
adjusted to develop a certain horse-power with a gas
of a certain richness, may not fulfil all expectations
if it is fed with a gas less rich, less pure, hotter, and
the like. The altitude also has some influence on the
efficiency of the engine. As it increases, the density of
the mixture diminishes; that is to say, for the same vol-
ume the engine is using a smaller amount. From this
it follows that a gas-engine ought to be adjusted as a
general rule on the spot where it is to be used.
The fulfilment of this condition is particularly im-
portant in the case of explosion-engines, because an
advancement or retardation of only one-half a second
in igniting the explosive mixture will cause a consid-
erable loss in useful work. From this it would follow
that gas-engines should be periodically inspected in
order that they may operate with the highest efficiency
and economy. As in the case of steam-engines, it is
TESTING THE ENGINE 127
f
advisable to take indicator records which afford con-
clusive evidence of the perturbations to which every
engine is subject after having run for some time.
Most gas-engine users either have no indicating in-
struments at their disposal or else are not sufficiently
versed in their employment and the interpretation of
their records to study perturbations by their means.
For this reason the advice of experts should be sought,
men who understand the meaning of the diagrams
taken and who are able by their means to effect a con-
siderable saving in gas.
CHAPTER VIII
HOW TO START AN ENGINE PRELIMINARY PRECAU-
TIONS
THE first step which is taken in starting an engine
driven by street-gas is, naturally, the opening of the
meter-cock and the valves between the meter and
the engine. When the gas has reached the engine, the
rubber bags will swell up and the anti-pulsator dia-
phragm will be forced out. The drain-cock of the gas-
pipe is then opened. In order to ascertain whether
the flow of gas is pure, a match is applied to the outlet
of the cock. The flame is allowed to burn until it
changes from its original blue color to a brilliant
yellow.
If the hot-tube system of ignition be employed, the
Bunsen burner is ignited, care being taken that the
flame emerging from the tube is blue in color. If
necessary the admission of air to the burner is regu-
lated by the usual adjusting-sleeve. A white or smoky
flame indicates an insufficient supply of air to the
burner. A characteristic sooty odor is still other evi-
dence of the same fact. Sometimes a white flame may
be produced by the ignition of the gas at the opening
of the adjusting-sleeve. A blue or greenish flame is
that which has the highest temperature and is the one
128
LIGHTING THE HOT TUBE 129
which should, therefore, be obtained. About five or
ten minutes are required to heat up the tube, owing to
the material of which it is made. When the proper
temperature has been attained the tube becomes a daz-
zling cherry red in color. While the tube is being
heated up, it is well to determine whether the engine
is properly lubricated and all the cups and oil reser-
voirs are duly filled up. The cotton waste of the
lubricators should be properly immersed, and the drip
lubricators examined to determine whether they are
supplying their normal quantity of oil.
The regulating-levers of the valves should be oper-
ated in order to ascertain whether the valves drop upon
their seats as they should. The stem of the exhaust-
valve should be lubricated with a few drops of petro-
leum.
If the ignition system employed be of the electric
type, with batteries and coils, tests should be made to
determine whether the current passes at the proper
time on completing the circuit with the contact
mounted on the intermediary shaft. This contact
should produce the characteristic hum caused by the
operation of the coil.
If a magneto be used in connection with the igni-
tion apparatus, its inspection need not be undertaken
whenever the engine is started, because it is not so
likely to be deranged. Still, it is advisable, as in the
case of ignition by induction-coils, to set in position
the device which retards the production of the spark.
This precaution is necessary in order to avoid a prema-
i 3 o GAS-ENGINES AND PRODUCERS
ture explosion, liable to cause a sharp backward revo-
lution of the fly-wheel.
After the ignition apparatus and the lubricators have
been thus inspected, the engine is adjusted with the
piston at the starting position, which is generally indi-
cated by a mark on the cam-shaft. The starting posi-
tion corresponds with the explosion cycle and is gen-
erally at an angle of 40 to 60 degrees formed by the
crank above the horizontal and toward the rear of the
engine. The gas-cock is opened to the proper mark,
usually shown on a small dial. If there be no mark,
the cock is slowly opened in order that no premature
explosion may be caused by an excess of gas.
The steps outlined in the foregoing are those which
must be taken with all motors. Each system, how-
ever, necessitates peculiar precautions, which are
usually given in detailed directions furnished by the
builder.
As a general rule the engines are provided on their
intermediary shafts with a " relief " or " half-com-
pression " cam. By means of this cam the fly-w r heel
can be turned several times without the necessity of
overcoming the resistance due to complete compres-
sion. Care should be taken, however, not to release
the cam until the engine has reached a speed sufficient
to overcome this resistance.
Engines of considerable size are commonly provided
with an automatic starting appliance. In order to
manipulate the parts of which this appliance is com-
posed, the directions furnished by the manufacturer
PRELIMINARY PRECAUTIONS i?i
9
must be followed. Particularly is this true of auto-
matic starters comprising a hand-pump by means of
which an explosive mixture is compressed, true be-
cause in the interests of safety great care must be taken.
The tightness and free operation of the valves or
clacks which are intended to prevent back firing
toward the pump should be made the subject of care-
ful investigation. Otherwise, the piston of the pump
is likely to receive a sudden shock when back firing oc-
curs.
When the engine has been idle for several days, it
is advisable, before starting, to give it several turns
(without gas) in order to be sure that all its parts
operate normally. The same precaution should be
taken in starting an engine, if a first attempt has failed,
in order to evacuate imperfect mixtures that may be
left in the cylinder. Before this test is made, the gas-
cock should, of course, be closed in order to prevent
an untimely explosion. It is advisable in starting an
engine not to bend the body over the ignition-tube,
because the tube is likely to break and to scatter dan-
gerous fragments.
Under no condition whatever should the fly-wheel
be turned by placing the foot upon the spokes. All
that should be done is to set it in motion by applying
the hand to the rim.
Care During Operation. When the engine has ac-
quired its normal speed, the governor should be looked
after in order that its free operation may be assured
and that all possibility of racing may be prevented.
1 32 GAS-ENGINES AND PRODUCERS
After the engine has been running normally for a time,
the cocks of the water circulation system should be
manipulated in order to adjust the supply of water to
the work performed by the engine. In other words
the cylinder should be kept hot, but not burning, as
previously explained in the paragraph in which the
water-jacket is discussed. The maintenance of a suit-
able temperature is extremely important so far as
economy is concerned. All the bearings should be in-
spected in order that hot boxes may be obviated.
Stopping the Engine. The steps to be taken in
stopping the engine are the following:
1. Stopping the various machines driven by the en-
gine, a practice which is followed in the case of all
motors ;
2. Throwing out the driving-pulley of the engine
itself, if there be one;
3. Closing the cock between the meter and the gas-
bags in order to prevent the escape of gas and the use-
less stretching of the rubber of the bags or of the anti-
pulsating devices;
4. Actuating the half-compression or relief cam as
the motor slows down, in order to prevent the recoil
due to the compression;
5. Closing the gas-admission cock;
6. Shutting off the supply of oil of free flowing
lubricators, and lifting out the cotton from the others.
If the engine be used to drive a dynamo, particularly
a dynamo provided with metal brushes, the precaution
should be taken of lifting the brushes before the en-
HOW TO STOP AN ENGINE 133
gine is stopped in order to prevent their injury by a
return movement of the armature-shaft;
7. Shutting off the cooling-water cock if running
water is used.
If the engine is exposed to great cold, the freezing
of the water in the jacket is prevented while the engine
is at rest, either by draining the jacket entirely, or by
arranging a gas jet or a burner beneath the cylinder
for the purpose of causing the water to circulate. If
such a burner be used the cocks of the water supply
pipe should, of course, be left open.
CHAPTER IX
PERTURBATIONS IN THE OPERATION OF ENGINES AND
THEIR REMEDY
IN this chapter will be discussed certain perturba-
tions which affect the operations of gas-engines to a
more marked degree than lack of care in their con-
struction. In previous chapters defects in operation
due to various causes have been dwelt upon, such as
objectionable methods in the construction of an engine,
ill-advised combination of parts, defects of installation,
and the like; and an attempt has been made to deter-
mine in each case the conditions which must be ful-
filled by the engine in order to secure efficiency and
economy at a normal load.
Difficulties in Starting. The preliminary precau-
tions to be taken in starting an engine having been in-
dicated, it is to be assumed that the advice given has
been followed. Nevertheless various causes may pre-
vent the starting of the engine.
Faulty Compression. Defective compression, as a
general rule, prevents the ignition of the explosive
mixture.' Whether or not the compression be imper-
fect can be ascertained by moving the piston back to
the period corresponding with compression, in other
words, that position in which all valves are closed.
134
FAULTY COMPRESSION 135
t
If no resistance be encountered, it is evident that the
air or the gaseous mixture is escaping from the cylin-
der by way of the admission-valve, the exhaust-valve,
or the piston. The valves, ordinarily seated by springs,
may remain open because their stems have become
bound, or because some obstruction has dropped in
between the disk and the seat. In a worn-out or badly
kept engine the valves are likely to leak. If that be
the case grinding is the only remedy. If a valve be
clogged, which becomes sufficiently evident by manip-
ulating the controlling levers, it is necessary simply to
clean the stem and its guides in order to remove the
caked oil which accumulates in time. If the engine be
new, the binding of the valve-stems is often caused by
insufficient play between the stems and their guides.
Should this prove to be the case, the defect is remedied
by rubbing the frictional surface of the stem with fine
emery paper and by lubricating it with cylinder-oil.
The exhaust-valve, however, should be lubricated only
with petroleum.
It is not unlikely that the exhaust-valve may leak
for two other reasons. In the first place, the tension of
the spring which serves to return the valve may have
lessened and may be insufficient to prevent the valve
from being unseated during suction. Again, the screw
or roller serving as a contact between the lever and the
valve-stem, may not have sufficient play, so that the
lengthening of the stem on account of its expansion
may prevent the valve from falling back on its seat.
The first-mentioned defect is remedied by renewing
136 GAS-ENGINES AND PRODUCERS
the spring, or by the provision of an additional spring
or of a counterweight in order to prevent the stoppage
of the motor. The second defect can be remedied by
regulating the contact.
Leakage past the piston may be caused by the break-
ing of one or more rings, by wear or binding of the
rings, or by wear or binding of the cylinder. The
whistling caused by the air or the mixture as it passes
back proves the existence of this fault.
Presence of Water in the Cylinder. It may some-
times happen that water may find its way into the cyl-
inder with the gas by reason of the bad arrangement
of the piping. It may also happen that water may
enter the cylinder through the water-jacket joint
Again, the presence of water in the cylinder may be
due to condensation of the steam formed by the chem-
ical union of the hydrogen of the gas and the oxygen of
the air, which condensation is caused by the cool walls
of the cylinder. The water may sometimes accumulate
in the exhaust pipe and box, when they have been im-
properly drained, and may thus return to the cylinder.
Whatever may be its cause, however, the presence of
water in the cylinder impedes the starting of the en-
gine, because the gases resulting from the explosion are
almost spontaneously chilled, thereby diminishing the
working pressure.
If electric ignition be employed, drops of water may
be deposited between the contacts, thereby causing
short circuits which prevent the passing of the spark.
If there be no drain-cock on the cylinder, the dim*-
IMPERFECT IGNITION 137
'
culty of starting the engine can be overcome only by
ceaseless attempts to set it in motion. The leaky con-
dition of a joint as well as the presence of a particle of
gravel in the cylinder-casting, through which the water
can pass from the jacket, is attested by the bubbling up
of gas in the water-tank at the opening of the supply
tube. These bubbles are caused by the passage of the
gas through the jacket after the explosion. If such
bubbles be detected, the cylinder should be renewed
or the defect remedied. In order to obviate any dan-
ger, the stop-cocks of the water-jacket, which have
already been described in a previous chapter, should be
closed while the engine is idle.
Imperfect Ignition. The difficulties encountered in
starting an engine, and caused by imperfect ignition,
vary in their nature with the character of the .igni-
tion system employed, whether that system, for ex-
ample, be of the electric, or of the incandescent or hot
tube type. Frequently it happens that in starting an
engine a hot tube may break. If the tube be of porce-
lain the accident may usually be traced to improper
fitting or to the presence of water in the cylinder. If
the tube be of metal, its breaking is caused usually by
a weakening of the metal through long use an acci-
dent that occurs more often in starting the engine than
in normal operation, because the explosions at starting
are more violent, owing to the tendency of the supply-
pipes to admit an excess of gas at the beginning.
A misfire arising from a faulty tube in starting may
be caused by an obstruction or by leaks at the joints or
138 GAS-ENGINES AND PRODUCERS
in the body of the tube itself, thereby allowing a certain
quantity of the mixture to escape before ignition. This
defect in the tube is usually disclosed by a characteris-
tic whistling sound.
A tube may leak either at the bottom or at the .top.
In the first case, starting is very difficult, because the
part of the mixture compressed toward the tube will
escape through the opening before it reaches the in-
candescent zone. In the second case, ignition may be
FIG. 74. FIG. 75.
Ignition -tubes provided with needle valves to facilitate starting.
simply retarded to so marked an extent that a sufficient
motive effect cannot be produced. An example of this
retardation, artificially produced to facilitate the start-
ing and to obviate premature explosions, is found in a
system of ignition-tubes provided with a small cock
or variable valve (Figs. 74 and 75).
The mere enumeration of defects caused by leakage
is sufficient to indicate the remedy to be adopted. It
may be well to recall in this connection the important
part played by the ignition-valve. If it be leaky, or if
IGNITION BY BATTERY 139
its free operation be impeded, starting will always be
difficult.
Electric Ignition by Battery or Magneto. If the
electric ignition apparatus, whatever may be the
method by which the spark is produced, be imper-
fect in operation, the first step to be taken is to ascertain
whether the spark is produced at the proper time, in
other words, slightly after the dead center in the par-
ticular position given to the admission device at start-
ing. If a coil and a battery be employed, it is advis-
able to remove the plug and to place it with its arma-
ture upon a well-polished metal surface to produce an
electrical contact, preventing, however, the contact of
the binding post with this metallic surface. The same
method of inspection is adopted with the make-and-
break apparatus of an electric magneto. In both cases
it should be ascertained whether or not there is any
short-circuiting. The contacts should be cleaned w 7 ith
a little benzine if they are covered with oil or caked
grease.
If no spark is produced at the plug or at the make-
and-break device it may be inferred that the wires are
broken or that the generating apparatus is out of order.
A careful examination will indicate what measures are
to be taken to cure the defects.
Premature Ignition. It has several times been
stated that the moment of ignition of the gaseous mix-
ture has a pronounced influence on the operation of
gas-engines and upon their economy.
Premature ignition takes place when there is a vio-
140 GAS-ENGINES AND PRODUCERS
lent shock at the moment when the piston leaps from
the rear dead center to the end of the compression
stroke. The violent effects produced are all the more
harmful because they tend to overheat the interior of
the engine and thereby to increase in intensity.
Premature ignition may be due to several causes.
If a valveless hot tube be employed it may happen
that the incandescent zone is too near the base. If
the tube be provided with a valve, it very frequently
happens that the valve leaks or that it opens too soon.
In the case of electric ignition, the circuit may be
completed before the proper time, because of faulty
regulation. The suggestions made in the preceding
chapters indicate the method of remedying these
defects.
Faulty ignition may have its origin not only in the
method of ignition employed, but also in excessive heat-
ing of the internal parts of the engine, caused by con-
tinual overloading or by inadequate circulation of
water.
Passing to those cases of premature ignition of a
special nature which are not due to any functional de-
fect in the engine, but which are purely accidental in
origin, such as the uncleanliness of the parts within the
cylinder or the presence of some projecting part which
becomes heated to incandescence during compression,
it should first be stated that these ignitions, usually
termed spontaneous, often occur well in advance of the
end of the compression stroke. They are characterized
by a more marked shock than that caused by ordinary
UNTIMELY DETONATIONS 141
premature ignition and usually result in bringing the
engine to a complete stop in a very short time. These
spontaneous explosions counteract to such an extent
the impulse of the compression period, during which
the piston is moving back, that they have a tendency
to reverse the direction in which the engine is running.
In such cases a careful inspection and a scrupulous
cleaning of the cylinder and of the piston should be
undertaken.
The bottom of the piston is particularly likely to re-
tain grease which has become caked, and which is
likely to become heated to incandescence and sponta-
neously to ignite the explosive mixture.
Untimely Detonations. The sound produced by
the explosions of a normally operating engine can
hardly be heard in the engine-room. Untimely detona-
tions are produced either at the exhaust, or in the suc-
tion apparatus, near the engine itself. These detona-
tions are noisier than they are dangerous; still, they
afford evidence of some fault in the operation which
should be remedied.
Detonations produced at the exhaust are caused by
the burning of a charge of the explosive mixture in the
exhaust-pipe, which charge, for some reason, has not
been ignited in the cylinder, and has been driven into
the exhaust-pipe, where it catches fire on coming into
contact with the incandescent gases discharged from
the cylinder after the following explosion.
Detonations produced in the suction apparatus of
the engine, which apparatus is either arranged in the
142 GAS-ENGINES AND PRODUCERS
base itself or in a separate chest, are often noisier than
the foregoing. They are caused by the accidental back-
ward flowing of the explosive mixture, and by its igni-
tion outside of the cylinder. The accident may be
traced to three causes :
1. The suction-valve of the mixture may not be tight
and may leak during the period of compression, allow-
ing a certain quantity of the mixture to pass into the
suction-chest or into the frame. When the explosion
takes place in the cylinder that part of the mixture
which has passed back is ignited, as we have just seen,
thereby producing a very loud deflagration. The ob-
vious remedy consists in making the suction-valve tight
by carefully grinding it.
2. It may happen that at the end of the exhaust
stroke incandescent particles may /remain in the cylin-
der, which particles may consist of caked oil or may
be retained by poorly cooled projections. The result is
that the mixture is prematurely ignited during the suc-
tion period.
3. The engine is so regulated, particularly in the
case of English-built engines, as to effect what is tech-
nically called " scavenging " the products of combus-
tion. In order to obtain this result, the mixture-valve
is opened before the end of the exhaust stroke of the
piston and the closing of the exhaust-valve. Owing to
the inertia and the speed acquired by the products of
combustion shot into the exhaust-pipe after explosion,
a lowering of the pressure is produced in the cylinder
toward the end of the stroke, causing the entrance of
RETARDED EXPLOSIONS
'43
air by the open admission-valve and consequently
effecting the scavenging of the burnt gases, part of
which would otherwise remain in the cylinder. It is
evident that if a charge of the mixture has not been
normally exploded, either because its constituents have
not been mingled in the proper proportion, or because
the ignition apparatus has missed fire, this charge at the
moment of exhausting will pass out of the cylinder
without any acquired speed, and will flow back in part
at the end of the exhaust stroke past the prematurely
opened admission-valve, thereby lodging in the air suc-
tion apparatus. Despite the suction which takes place
immediately following the re-entrance of the gas int.o
the cylinder, a certain quantity of the mixture is still
confined in the suction-pipe and its branches, where it
will catch fire at the end of the exhaust stroke after the
opening of the mixture-valve.
In order to avoid these detonations it is necessary
simply to see to it that the mixture is regularly ignited.
This is accomplished by mixing the gas and air in
proper proportions or by correcting the ignition time.
Retarded Explosions. Retarded explosions consid-
erably reduce the power which an engine should nor-
mally yield, and sensibly increase the consumption.
They are due to three chief causes: (i), faulty igni-
tion; (2), the poor quality of the mixture; (3), com-
pression losses. The existence of the defect cannot be
ascertained with any certainty without the use of an
indicator or of some registering device which gives
graphic records. Nevertheless, it is possible in some
144 GAS-ENGINES AND PRODUCERS
degree to detect retarded explosions, simply by ob-
serving whether there is a diminution in the power or
an excessive consumption, despite the perfect operation
and good condition of all the engine parts.
In order to remedy the defect it should be ascer-
tained if the compression is good, if the supply of gas
is normal, and if the conditions under which the mix-
ture of air and gas is produced have not been changed.
Lastly, the ignition apparatus is gradually adjusted to
accelerate its operation until a point is reached when,
after explosion, shocks are produced which indicate an
excessive advance. The ignition apparatus is then ad-
justed to a point slightly ahead of the corresponding
position. Recalling the descriptions already given of
the various systems of ignition, the manner of regulat-
ing the moment of ignition in each case may be sum-
marized as follows :
1. For the valveless incandescent tube, provided
with a burner the position of which can be varied,
ignition can be accelerated by bringing the burner
nearer to the base. Retardation is effected by moving
the burner away from the base.
2. In the case of the incandescent tube of the fixed
burner type, the moment of ignition will depend upon
the length of the tube. The retardation will be greater
as the tube is shorter, and vice versa.
3. If the tube be provided with an ignition-valve,
the time of ignition having been regulated by the
maker, regulation need not be undertaken except if the
valve-stem be worn or the controlling-cam be distorted.
RETARDED EXPLOSIONS 145
If these defects should be noted, the imperfect parts
should be repaired or renewed.
4. In electric igniters the controlling apparatus
is generally provided with a regulating device which
may be manipulated during the operation of the motor.
If the manual adjustment of the regulating apparatus
be unproductive of satisfactory results, it is advisable
to ascertain whether the spark is being produced nor-
mally. Before the engine has come to a stop, one of
the valve-casings is raised, and through the opening
thus produced it is easily seen whether the spark is of
sufficient strength, the engine in the meanwhile being
turned by hand. Care should always be taken to purge
the cylinder of the gas that it may contain, in order to
prevent dangerous explosions. If the spark should
prove to be too feeble, or if there be no spark at all, de-
spite the fact that every part of the mechanism is prop-
erly adjusted, it may be inferred that the fault lies with
the current and is caused by
1. Imperfect contact with the binding-posts, with
the conducting wire, or with the contact-breaking
members;
2. A short circuit in one of the dismembered pieces;
3. The presence of a layer of oil or of caked grease
forming an insulator, injurious to induction, between
the armature and the magnets;
4. A deposit of oil or moisture on the contact-break-
ing parts;
5. The exhaustion of the magnets, which, however,
occurs only after several years of use, except when the
146 GAS-ENGINES AND PRODUCERS
magneto has been subjected for a long time to a high
temperature.
The mere discovery of any of these defects suffi-
ciently indicates the means to be adopted in remedying
them.
Lost Motion in Moving Parts. Lost motion of
the moving parts is due to structural errors. Its cause
is to be found in the insufficient size of the frictional
bearing surfaces, and improper proportioning of shafts,
pins, and the like. The result is a premature wear
which cannot be remedied. Imperfect adjustment,
lack of care, and bad lubrication, may also hasten the
wear of certain parts. This wear is manifested in
shocks, occurring during the operation of the engine,
shocks which are particularly noticeable at the moment
of explosion.
Besides the inconveniences mentioned, wearing of the
gears and of the moving parts leads to derangement of
the power-transmitting members.
So far as the admission and exhaust valves are con-
cerned, the wearing of the cams, rollers, and lever-
pivots is evidenced by a retardation in the opening of
these valves and an acceleration in their closing.
The ignition, whatever may be the system employed,
is affected by lost motion and is retarded. The engine
appreciably loses in power, and its consumption be-
comes excessive.
Overheated Bearings. Apart from the imperfect
adjustment of a member, it may happen that the bush-
ings of the main bearings of the ends of the connecting-
OVERHEATED BEARINGS 147
rod, and of the piston-pivot, may become heated be-
cause of excessive play, or of too much tightening, or of
a lack of oil, or of the employment of oil of bad quality.
The overheating may lead to the binding of frictional
surfaces and even to the fusion of bushings if they be
lined with anti-friction metal. In order to avoid the
overheating of parts, it is advisable, while the engine
is running, to touch them from time to time with the
back of the hand. As soon as the slightest overheating
is felt, the temperature may be lowered often by liberal
oiling. If this be inadequate and if for special reasons
it is impossible to stop the engine, the overheated part
may be cooled by spraying it with soapy water.
If the overheating has not been detected or reduced
in time, a characteristic odor of burnt oil will -be per-
ceived, accompanied by smoke. The part overheated
will then have attained a temperature so high that it
cannot be touched with the hand. Should this occur,
it is inadvisable to employ oil, because it would im-
mediately burn up and would Only aggravate the con-
ditions. Cotton waste should be carefully applied to
the overheated member, and gradual spraying with
soapy water begun.
In special cases where the lubricating openings or
channels are not likely to be obstructed, a little flowers
of sulphur may be added to the- oil, if this be very fluid.
Castor oil may also be successfully employed.
If the binding of the rubbing surfaces should pre-
vent the reduction of the overheated member's tempera-
ture, the engine must necessarily be stopped, and the
148 GAS-ENGINES AND PRODUCERS
parts affected detached. All causes of binding are re-
moved by means of a steel scraper. The surfaces of the
bushings and of the shaft which they receive are
smoothed with a soft file and then polished with fine
emery paper. Before the parts are replaced, the pre-
caution of ascertaining whether they touch at all points
should be taken. Careful inspection and copious lubri-
cation should, of course, be undertaken when the en-
gine is again started.
Overheating of the Cylinder. The overheating of
the cylinder may be due to a complete lack of water
in the jacket or to an accidental diminution in the quan-
tity of water supplied. If this discovery is made too
late, and if the cylinder has reached a very high tem-
perature, the circulation of the water should not be
suddenly re-established, because of the liability of
breaking the casting. It is best to stop the engine and
to restore the parts to their normal condition.
It is well to recall at this point that if the calcareous
incrustation of the water-jacket or the branch pipes
should hinder the free circulation of water, cleaning is,
of course, necessary. The jacket may be washed sev-
eral times with a twenty per cent, solution of hydro-
chloric acid. After this treatment the jacket should, of
course, be rinsed with fresh water before the piping of
the water-circulating apparatus is again connected.
Overheating of the Piston. If the overheating of
the piston is not due to faulty adjustment, it may be
caused by lack of oil or to the employment of a lubri-
cant not suitable for the purpose. In a previous chap-
OVERHEATED PISTON
149
ter the importance of using a special oil for cylinder
lubrication has been insisted upon. The overheating
of the piston can also result from that of the piston-pin.
Should this be the case it is advisable to stop the engine,
to ascertain the condition and the degree of lubrica-
tion of this member and its bearing. Overheating of
the piston is manifested by an increase of the tempera-
ture of the cylinder at the forward end. If this over-
heating be not checked, binding of the piston in the
cylinder is likely to result.
Smoke Arising from the Cylinder. This is gen-
erally a sign either of overheating, which causes the
oil to evaporate, or of an abnormal passage of gas,
caused by the explosion. Abnormal passage of gas
may result from wear or from distortion of the cylin-
der, or from wear or breakage of the piston-rings. The
result is always the overheating of the cylinder and a
reduction in compression and power.
If the engine is well kept and shows no sign of wear,
leakage may be caused simply by the fouling of the
piston-rings, which then adhere in their grooves and
have but insufficient play. This defect is obviated by
cleaning the rings in the manner explained in Chapter
VII.
Lubrication is faulty when the quantity of lubricant
supplied is either insufficient or too abundant, or when
the oils employed are of bad quality. It has already
been shown that insufficient lubrication and the utiliza-
tion of bad oils leads to the overheating of the moving
parts.
150 GAS-ENGINES AND PRODUCERS
Insufficient lubrication may be caused by imperfect
operation of the lubricators, or, particularly during
cold weather, by too great a viscosity or congelation of
the oil. If a lubricator be imperfect in its operation,
the condition of its regulating mechanism should be as-
certained, if it has any, and an examination made to dis-
cover any obstruction in the oil-ducts. Such obstruc-
tions are very likely to occur in new devices which have
been packed in cotton waste or excelsior, with the re-
sult that the particles of the packing material often find
their way into openings.
An oil may be bad in quality because of its very
nature, or because of the presence of foreign bodies.
In either case an oil of better quality should be sub-
stituted.
The freezing of oil by intense cold may be retarded
by the addition of ordinary petroleum to the amount of
10 to 20 per cent.
An excess of oil in the bearings results simply in
an unnecessary waste of lubricant, and the splashing
of oil on the engine and about the room. If too much
011 be used in the cylinder, grave consequences may be
the result; for a certain quantity of the oil is likely to
accumulate within the cylinder, where it burns and
forms a caky mass that may be heated to incandescence
and prematurely ignite the explosive mixture. Es-
pecially in producer-gas engines is an excess of cylin-
der-lubricant likely to cause such accidents. Indeed,
the temperature of explosion not being as high as in
street-gas engines, the excess oil cannot be so readily
SUDDEN STOPS ici
removed with certainty by evaporation or combustion.
On the other hand, the compression of the mixture
being generally higher, premature ignition is very
likely to occur.
Back Pressure to the Exhaust. How the pipes and
chests for the exhaust should be arranged in order not
to exert a harmful influence on the motor has already
been explained. Even if the directions given have been
followed, however, the exhaust may not operate prop-
erly from accidental causes. Among these causes may
be mentioned obstructions in the form of foreign bod-
ies, such as particles of rust, which drop from the in-
terior of the pipes after the engine has been running
for some time and which, accumulating at any place in
the pipe, are likely to clog the passage. Furthermore,
the products of combustion may contain atomized cyl-
inder oil which finds its way into the exhaust-pipe.
This oil condenses on the walls of the elbows and bends
of the pipe in a deposit which, as it carbonizes, is con-
verted into a hard cake and which reduces the cross-
section of the passage, thereby constituting a true ob-
stacle to the free exhaust of the gases.
These various defects are manifested in a loss in
engine power as well as in an abnormal elevation of
the temperature of the parts surrounding the exhaust
opening.
Sudden Stops. Sudden stops are occasioned by
faulty operation of the engine, and by imperfect fuel
supply. Among the first class the chief causes to be
mentioned are the following:
152 GAS-ENGINES AND PRODUCERS
1. Overheating, which has already been discussed
and which may block a moving part.
2. Defective" ignition.
3. Binding of the admission-valve or of the exhaust-
valve, preventing respectively suction or compression.
4. The breaking or derangement of a member of the
distributing mechanism.
5. A weakening of the exhaust-valve spring, so that
the valve is opened by the suction of fresh quantities of
mixture.
These faults are due to carelessness and improper in-
spection of the engine.
So far as the fuel supply of the engine is concerned,
the causes of stoppage will vary if street-gas or pro-
ducer-gas be employed. In the former case the diffi-
culty may be occasioned by the improper operation of
the meter, by the formation of a water-pocket in the
piping, by the binding of an anti-pulsator valve, by the
derangement of a pressure-regulator, or by a sudden
change in the gas pressure when no pressure-regulator
is employed. If producer-gas be used, stoppages may
be occasioned by a sudden change in the quality, quan-
tity, or temperature of the gas. These defects will be
examined in detail in the chapter on Gas-Producers.
CHAPTER X
PRODUCER-GAS ENGINES
THUS far only street-gas or illuminating-gas engines
have been discussed. If the engine employed be small
10 to 15 horse-power, for instance street-gas is a
fuel, the richness, purity and facility of employment
of which offsets its comparatively high cost. But
the constantly increasing necessity of generating
power cheaply has led to the employment of special
gases which are easily and cheaply generated. Such
are the following:
Blast-furnace gases,
Coke-oven gases,
Fuel-gas proper,
Mond gas,
Mixed gas,
Water-gas,
Wood-gas.
The practical advantages resulting from the utiliza-
tion of these gases in generating power were hardly
known until within the last few years. The many uses
to which these gases have been applied in Europe since
1900 have definitely proved the industrial value of pro-
ducer-gas engines in general.
The steps which have led to this gradually increasing
use of producer-gas have been learnedly discussed and
commented upon in the instructive works and publica-
153
154 GAS-ENGINES AND PRODUCERS
tions of Aime Witz, Professor in the Faculty of
Sciences of Lille, in those of Dugald Clerk, of Lon-
don, F. Grover, of Leeds, and Otto Giildner, of Mu-
nich, and in those of the American authors, Golding-
ham, Hiscox, Hutton, Parsell and Weed, etc. The
new tendencies in the construction of large engines may
be regarded as an interesting verification of the fore-
casts of these men forecasts which coincide with the
opinion long held by the author. Aime Witz has
always been an advocate of high pressures and of in-
creased piston speed. English builders who made ex-
periments in this direction conceded the beneficial re-
sults obtained; but while they increased the original
pressure of 28 to 43 pounds per square inch employed
five or six years ago to the pressure of 85 to 100 pounds
per square inch nowadays advocated, the Germans, for
the most part, have adopted, at least in producer-gas
engines, pressures of 114 to 170 pounds per square
inch and more.
High Compression. In actual practice, the problem
of high pressures is apparently very difficult of solu-
tion, and many of the best firms still seem to cling to
old ideas. The reason for their course is, perhaps, to
be found in the fact that certain experiments which they
made in raising the pressures resulted in discouraging
accidents. The explosion-chambers became over-
heated; valves were distorted; and premature ignition
occurred. Because the principle underlying high pres-
sures was improperly applied, the results obtained were
poor.
HIGH COMPRESSION
.
High pressures cannot be used with impunity in cyl-
inders not especially designed for their employment;
and this is the case with most engines of the older type,
among which may be included most engines of English,
French, and particularly of American construction.
In American engines notably, the explosion-chamber,
the cylinder and its jacket, are generally cast in one
piece, so that it is very difficult to allow for the free ex-
pansion of certain members with the high and unequal
temperatures to which they are subjected (Fig. 22).
Some builders have attempted to use high pressures
without concerning themselves in the least with a modi-
fication of the explosive mixture. The result has been
that, owing to the richness of the mixture, the explosive
pressure was increased to a point far beyond that for
which the parts were designed. Sudden starts and stops
in operation, overheating of the parts, and even break-
ing of crank-shafts, were the results. The engines had
gained somewhat in power, but no progress had been
made in economy of consumption, although this was
the very purpose of increasing the compression.
High pressures render it possible to employ poor
mixtures and still insure ignition. A quality of street-
gas, for example, which yields one horse-power per
hour with 17.5 cubic feet and a mixture of i part gas
and 8 of air compressed to 78 pounds per square inch,
will give the same power as 14 cubic feet of the same
gas mixed with 12 parts of air and compressed to 171
pounds per square inch.
" Scavenging" of the cylinder, a practice which en-
156 GAS-ENGINES AND PRODUCERS
gineers of modern ideas seem to consider of much im-
portance, is better effected with high pressures, for the
simple reason that the explosion-chamber, at the end
of the return stroke, contains considerably less burnt
gases when its volume is smaller in proportion to that
of the cylinder.
In impoverishing the mixture to meet the needs of
high pressures, the explosive power is not increased and
in practice hardly exceeds 365 to 427 pounds per square
FIG. 76. Method of cooling the cylinder-head.
inch. With the higher pressures thus obtained there
is consequently no reason for subjecting the moving
parts to greater forces.
Cooling. The increase in temperature of the cylin-
der-head and of the valves, due wholly to high com-
pression, is, perfectly counteracted by an arrangement
which most designers seem to prefer, and which, as
shown in the accompanying diagram (Fig. 76), con-*
sists in placing the mixture and exhaust-valves in a
passage forming a kind of antechamber completely
COOLING 157
. f
surrounded by water. The immediate vicinity of this
water assures the perfect and equal cooling of the valve-
seats. This arrangement, while it renders it possible to
reduce the size of the explosion-chamber to a mini-
mum, has the additional mechanical advantage of en-
abling the builder to bore the seats and 'valve-guides
with the same tool, since they are all mounted on the
same line. From the standpoint of efficiency, the de-
sign has the advantage of permitting the introduction
of the explosive mixture without overheating it as it
passes through the admission-valve, which obtains all
the benefit of the cooling of the cylinder-head, literally
surrounded as it is by water.
In large engines the cooling effect is even heightened
by separately supplying the jackets of the cylinder-
head and of the cylinder. In engines of less power the
top of the cylinder-head jacket is placed in communica-
tion with that of the cylinder, so that the coldest water
enters at the base of the head and, after having there
been heated, passes around the cylinder in order finally
to emerge at the top toward the center. The water hav-
ing been thus methodically circulated, the useful effect
and regularity of the cooling process is increased.
Notwithstanding the care which is devoted to water
circulation, it is advisable to run the producer-gas en-
gine " colder " than the older street-gas types, in which
the more economic speed is that at which the water
emerges from the jacket at about a temperature of 104
degrees F. It would seem advisable to meet the re-
quirements of piston lubrication by reducing to a mini-
158 GAS-ENGINES AND PRODUCERS
mum the quantity of heat withdrawn by the circulating
water. Indeed, the personal experiments of the author
bear out this principle.
For street-gas engines, however, the cylinders should
be worked at the highest possible temperature consistent
with the recfuirements of lubrication. It should not be
forgotten that, in large engines fed with producer-gas,
economy of consumption is a secondary consideration,
because of the low quantity of fuel required. The cost,
moreover, may well be sacrificed to that steadiness of
operation which is of such great importance in large en-
gines furnishing the power of factories; for in such
engines sudden stops seriously affect the work to be
performed. For this reason engine builders have been
led to the construction of motors provided with very
effective cooling apparatus. Since the circulation
of the water around the explosion-chamber and the
cylinder is not sufficient to counteract the rise of tem-
perature, it has become the practice to cool separately
each part likely to be subjected to heat. The seats of
the exhaust-valves, the valves themselves, the piston,
and sometimes the piston-rod, have been provided with
water-jackets.
Premature Ignition. Returning to the causes of the
discouragements encountered 'by some designers who
endeavored to use high pressures, it has already been
mentioned that premature ignition of the explosive
mixture in cylinders not suited for high pressures is one
reason for the bad results obtained. An explanation of
these results is to be found in the high theoretical tern-
PREMATURE IGNITION 159
f
perature corresponding with great pressures and in the
quantity of heat which must be absorbed by the walls
of the explosion-chamber. These two circumstances
are in themselves sufficient to produce spontaneous igni-
tion of excessively rich mixtures, compressed in an oyer-
heated chamber unprovided with a sufficient circulation
of water. A third cause of premature ignition may also
be found in the old system of ignition which, in most
English engines, consists of a metallic or porcelain tube,
,the interior of which communicates with the explosion-
chamber, an exterior flame being employed to heat the
tube to incandescence. In tubes of this type which are
not provided with a special ignition-valve, the time of
ignition is dependent only on the moment when the ex-
plosive mixture, driven into the tube, comes into con-
tact, at the end of the compression stroke, with the in-
candescent zone, thereby causing the ignition. This
very empirical method leads either to an acceleration
or retardation of the ignition, depending upon the
temperature of the tube, the position of the red-hot zone,
its dimensions, and the temperature of the mixture,
which is determined by the load of the engine. Al-
though this system, the only merit of which is its sim-
plicity, may meet the requirements of small engines,
there is not the slightest doubt that it is quite inapplica-
ble to those of more than 20 to 25 horse -power, for
in such engines greater certainty in operation is de-
manded. Even if only the more improved of the two
types of hot-tube ignition be considered, with or with-
out valves, it must still be held that they are inapplica-
160 GAS-ENGINES AND PRODUCERS
ble to high compression engines. The ignition-valve
is the part which suffers most from the high tem-
perature to which it is subjected. Its immediate
proximity to the incandescent tube, and its contact
with the burning gas when it flares up, render
it almost impossible to employ any cooling arrange-
ment. Although w r ith the exercise of great care it may
work satisfactorily in engines of normal pressure, it is
evident that it cannot meet the requirements of high-
pressure engines, because the temperature of the com-
pressed mixture is such that the charge is certain to
catch fire by mere contact with the overheated valve.
In industrial engines of small size, premature ignition
has little, if any, effect except upon silent operation and
economic consumption. This does not hold true, how-
ever, of large engines. Besides the inconveniences men-
tioned, there is also the danger of breaking the cranks
or other moving parts. The inertia of these members is
a matter of some concern, because of their weight and
of the linear speed which they attain in large engines.
Some idea of this may be obtained when it is considered
that in a producer-gas or blast-furnace-gas engine hav-
ing a piston diameter of 24 inches and an explosive
pressure of 299 pounds per square inch, the force ex-
erted at the moment of explosion is about 132,000
pounds. Naturally, engine builders have adopted the
most certain means of avoiding premature ignition and
its grave consequences.
The method of ignition which at present seems to be
preferred to any other for producer-gas is that employ-
PRODUCER-GAS ENGINES 161
ing a break-spark obtained with the magneto apparatus
previously described. Some builders of large engines,
particularly desirous of assuring steadiness of running,
have provided the explosion-chamber with two inde-
pendent igniters. It may be that they have adopted
this arrangement largely for the purpose of avoiding
the inconveniences resulting from a failure of one of the
igniters, rather than for the purpose of igniting the
mixture in several places so as to obtain a more uniform
ignition and one better suited for the propagation of
the flame.
The Governing of Engines. Various methods have
been adopted for the purpose of varying the mo-
tive power of an engine between no load and full load,
still preserving, however, a constant speed of rotation.
These methods consist in changing either the quantity
or the quality of the mixture admitted into the cylinder.
Thus it may happen that an engine may be supplied:
1. With a mixture constant in quality and in quan-
tity;
2. With a mixture variable in quality and constant
in quantity;
3. With a mixture constant in quality and variable
in quantity.
I. Mixture Constant in Quality and Quantity. This
method implies the use of the hit-and-miss system of
admission, in which the number of admissions and ex-
plosions varies, while the value or the composition of
each admitted charge remains as constant as the com-
pression itself (Fig. 34) . This system has already been
1 62 GAS-ENGINES AND PRODUCERS
referred to and its simplicity fully set forth. By its
use a comparatively low consumption is obtained, even
when the engine is not running at full load. On the
other hand, it has the disadvantage of necessitating the
employment of heavy fly-wheel to preserve cyclic reg-
ularity.
2. Mixture Variable in Quality and Constant in
Quantity. The governing system most commonly em-
ployed to obtain a mixture variable in quality and con-
stant quantity is based upon the control of the gas-
admission valve by means of a cam having a conical
longitudinal section, as shown in Fig. 35. This cam,
commonly called a " conical cam," is connected with a
lever actuated from the governor. As the lever swings
under the action of the governor, the cam is shifted
along the half-speed shaft of the engine. The result is
that the gas-admission valve is opened for a longer or
shorter period.
In another system a cylindrical valve is mounted
between the chamber in which the mixture is formed
and the gas-supply pipe, the valve being carried on the
same stem as the mixture-valve itself. The cylindrical
valve is displaced by the governor so as to vary the
quantity of gas drawn in with relation to the quantity
of air.
When the engines are fed with producer-gas the
parts which have just been described should be fre-
quently inspected and cleaned ; for they are only too
easily fouled.
Engines thus governed should be run at high pres-
PRODUCER-GAS ENGINES 163
sure so as to insure the ignition of the producer-gas
mixtures formed when the position of the cam cor-
responds with the minimum opening of the gas-valve.
Powerful governors should be employed, capable of
overcoming the resistance offered by the cylindrical
valve or the cam.
It may often happen that variations in the load of the
engine render it necessary to actuate the air valve, so
as to obtain a mixture which will be ignited and ex-
ploded under the best possible conditions.
3. Mixture Constant in Quality and Variable in
Quantity. In supplying an engine with a mixture con-
stant in quality and variable in quantity, the compres-
sion does not remain constant. The quantity of mixture
drawn in by the cylinder may even be so far reduced
that the pressure drops below the point at which igni-
tion takes place. For that reason engines of this type
should be run at high pressures.
The variation of the quantity of mixture may be
effected in various ways. The simplest arrangement
consists in mounting a butterfly-valve in the mixture-
pipe, which valve is controlled by the governor and
throttles the passage to a greater or lesser degree.
A very striking solution of the problem consists in vary-
ing the opening of the mixture-valve itself. To attain
this end the valve is moved by levers. The point of
application of one of these levers is displaced under
the action of the governor so as to vary the travel of
the valve within predetermined limits. Under these
conditions a mixture of constant homogeneity is intro-
1 64 GAS-ENGINES AND PRODUCERS
duced into the cylinder, so proportioned as to insure
ignition even at low pressures.
In recent experiments conducted by the author it was
proved that with this governing system ignition still
takes place even though the pressure has dropped to
FIG. 760. Governing system for producer-gas engines.
43 pounds per square inch. This system has the merit
of rendering it possible to employ ordinary governors
of moderate size, since the resistance to be overcome
at the point of application of the lever is comparatively
small. In the accompanying illustration the Otto
Deutz system is illustrated.
CHAPTER XI
PRODUCER-GAS
IT may here be not amiss to point out the differences
between illuminating gas and those gases which are
called in English " producer " gases, and in French
" poor " gases, because of their low calorific value.
Street -Gas. This gas, the composition of which
varies with different localities, has a calorific value,
which is a function of its composition, and which varies
from 5,000 to 5,600 calories per cubic meter (19,841 to
24,896 B. T. U. per 35.31 cubic feet) measured at con-
stant pressure and corrected to o degrees C. (32 degrees
F.) at a pressure of 760 millimeters (29.9 inches of
mercury, or .atmospheric pressure), not including the
latent heat of the water of condensation. The follow-
ing table gives the average volumetric composition of
illuminating gas in various cities:
CITIES.
/
London.
Manches-
ter.
New
York.
Paris.
Berlin.
Hydrogen
48
4.6
4O
C2
co
Carbon monoxide
4
T"
7
4
6
q
Methane
38
3 C
T.J
32
T. T.
Various hydrocarbons
4
6
7
6
C
Carbon dioxide
4
T.
2
Nitrogen
-
2
8
4
I
Oxygen
j
. I
100
100
IOO
IOO
IOO
165
166 GAS-ENGINES AND PRODUCERS
Furthermore, these constituents vary within certain
limits. This is also true of the calorific value. Experi-
ments made by the author have demonstrated that in
the same place at an interval of a few hours, variations
of approximately ten per cent, occur.
Composition of Producer-Gases. - The average
chemical composition of producer-gases varies with the
conditions under which they are generated and the na-
ture of the fuel. The following are the proportions of
its constituents expressed volumetrically :
G
AS.
Blast
Furnace.
Producer.
Mond.
Mixed
(Fichet) .
Water
(Strache).
Wood
(Riche).
Nitrogen and oxygen. . . .
Carbon monoxide
Carbon dioxide .
60
2 4
I 2
59
25
c
4 2
I I
16
5
20
7
5
40
I
29
I i
Hydrocarbons
2
2
2
3
I
I r
Hydrogen . . ....
2
q
2Q
j
2O
CQ
1 )
A A
100
100
100
100
100
100
Calorific value in calories.
Average weight of a cubic
meter in kilos .
950
I. 3O
1,100
I. IO
1,400
I .02
1,300^
I.OC
2,400
o 680
2,960
o 824
Or of a cubic foot in
pounds
O.OO8
O.OO7
O.OO6
w J
0.0068
0.0042
O OO C I
Blast-furnace gas has been used for generating power
by means of gas-engines for about ten years. At the
present time it is used in engines of very high power,
a discussion of which engines more properly belongs
to a work on metallurgy, and has no place, therefore,
in a manual such as this.
Producer-gas, in the true sense of the term, is gen-
crated in special apparatus either under pressure or by
PRODUCER-GAS 167
.
suction in a manner to be described in the following
chapters.
Mond gas is produced in generators of the blowing
or pressure type from bituminous coal, necessitating the
employment of special purifiers and permitting the col-
lection of the by-products of the fractional distillation
of the coal. Mond gas plants are, therefore, rather
complicated and can be advantageously utilized only
for large engines. More exhaustive information can
be obtained from the descriptions published by the
builders of Mond gas generators.
Mixed gas is generated in apparatus arranged so that
the retort is kept at a high temperature, thereby produc-
ing a gas richer in hydrogen than that made by pro-
ducers. It should be observed that in practice the gen-
erators at present used yield a producer-gas, the calo-
rific value of which fluctuates between 1,000 and 1,400
calories per cubic meter (3,968 to 5,158 B. T. U. per
35.31 cubic feet) ; and the composition varies accord-
ingly, in the manner that has already been indicated
in the tables for producer-gas and mixed gas. There
is no necessity, therefore, for drawing a distinction be-
tween these two qualities of gas.
Water-gas should theoretically be composed of 50
per cent, carbon monoxide and 50 per cent, hydrogen,
resulting from the decomposition of steam by in-
candescent coal. In practice, however, it contains a
little nitrogen and carbon. dioxide. The gas is obtained
from generators in which air is alternately blown in to
fan the fire and then steam to produce gas. Water-gas
1 68 GAS-ENGINES AND PRODUCERS
is employed in soldering on account of its reducing
properties and of the high temperature of its flame.
The great quantity of carbon monoxide which it con-
tains renders it very poisonous and exceedingly danger-
ous, because it is generated -under pressure. From the
economical standpoint, its generation is more expen-
sive than that of producer-gas, for which reason its
employment in gas-engines is hardly of much value.
Wood-gas, the composition of which has already been
given, is generated in apparatus of the Riche type, the
principle of which consists in heating a cast retort
charged with any kind of fuel, namely wood, and ver-
tically mounted on a masonry base.
This apparatus should be of .particular interest to
the proprietors of sawmills, furniture factories, and the
like, since it offers a means of using the waste products
of their plants.
The relatively high proportion of carbon monoxide
in producer-gas is objectionable from a hygienic stand-
point, so much so, indeed, that it has attracted the atten-
tion of manufacturers. Carbon monoxide, the specific
gravity of which is 0.967, is a gas peculiarly poisonous
and dangerous. It cannot be breathed without baneful
effects, and is even more dangerous than carbonic-acid
gas, which eventually causes asphyxiation by reducing
the quantity of oxygen in the air. For this reason, it is
necessary to take the utmost precaution in efficiently and
continuously ventilating the rooms in which the gas-
generators and their accessories are installed. This
suggestion should be followed, above all, when the ap-
ASPHYXIATION 160
f '
paratus in question are installed in cellars and base-
ments. As a further precaution, where the plant is
rather large a workman should not be allowed to enter
the generator room alone.
Blowing-generators, or those in which the gas is pro-
duced under pressure, are more dangerous than suc-
tion-generators. In the former a leaky joint may cause
the vitiation of the surrounding air as the producer-gas
escapes; in the suction apparatus the same fault simply
causes more air to be drawn in.
Dr. Melotte recommends the following procedure
in cases of carbon monoxide asphyxiation:
CARBON MONOXIDE ASPHYXIATION
Cases of poisoning by carbon monoxide are both fre-
quent and dangerous. The gas is extremely poisonous,
and all the more dangerous because it is odorless, color-
less and tasteless. When it comes into contact with the
blood, it forms a combination so stable that it is reacted
upon by the oxygen of the air only with difficulty. It
follows, therefore, that with each respiration of air
charged with carbon monoxide, a certain quantity of
blood is poisoned. In consequence of this, there is a
possibility of poisoning in open air.
Symptoms. The symptoms observed will vary with
the manner in which the blood has been poisoned.
There are two ways in which this poisoning can occur.
The one depends upon whether the atmosphere contains
an excess of carbon monoxide; the other whether the
air breathed contains only traces of the gas.
170 GAS-ENGINES AND PRODUCERS
Gradual, Rapid Asphyxiation. At first a vague
sickness is felt, rapidly followed by violent headaches,
vertigo, anxiety, oppression, dimness of vision, beating
of the pulse at the temples, hallucinations, and an irre-
sistible desire to sleep. If at this stage the patient has a
sufficient idea of danger to prompt him to open a
window or door, he will escape death.
In the second stage, the victim's legs are paralyzed,
but he can still move his arms and his head. The mind
still preserves its clearness, and in a measure assists the
further process of asphyxiation because of its impo-
tency. Then follow coma and death.
Slow, Chronic Asphyxiation. Slow, chronic as-
phyxiation is not infrequent. Its symptoms are often
difficult to detect. Poisoning is manifested by weak-
ness, cephalalgia, vomiting, pallor, general anemia, las-
situde, and local paralysis. If any of these symptoms
appear in the men who work in the vicinity of the pro-
ducers, immediate steps should be taken to prevent the
possibility of carbon monoxide asphyxiation.
FIRST AID IN CASES OF CARBON MONOXIDE POISONING
It has already been stated that the oxygen of the air
has no oxidizing effect upon blood contaminated by
carbon monoxide. Only a liberal current of pure
oxygen can oxidize the combination formed and render
hematosis possible. This liberal current can be ob-
tained from an oxygen tank of the portable variety, pro-
vided with a tube carrying at its free end a mask which
METHODS OF RESUSCITATION 171
is held over the mouth and the nostrils. The absorption
of gas takes place by artificial respiration, which is
effected in several ways. The most practical of these
are the Sylvester and Pacini methods.
Sylvester Method. The patient is laid on his back.
His arms are raised over his head and then brought
back on each side of the body. This operation is re-
peated fifteen times per minute approximately. The
method is very frequently employed and is excellent in
its results.
The Pacini Method. Four fingers are placed in
the pit of the arm, with the thumb on the shoulder.
The shoulder is then alternately raised and lowered,
producing a marked expansion of the chest. This
method is the more effective of the two. The move-
ments described are repeated fifteen to twenty times
each minute very rhythmically.
One or the other of these two methods of treatment
should be .immediately applied in serious cases. Cer-
tain preliminary precautions should be taken in all
cases, however. The patient should be carried to a well-
ventilated and moderately heated room, stripped of his
clothes, and warmed by water-bottles and heated linen.
Reflex action should be excited, the peripheral nervous
system stimulated in order to contract the heart and the
respiratory muscles, and the precordial region cauter-
ized. In addition to this treatment, the region of the dia-
phragm should be rubbed and pinched, the skin rubbed,
cold showers given, flagellations administered, urtica-
tions (whipping with nettles) undertaken, the skin and
172 GAS-ENGINES AND PRODUCERS
the mucous membranes excited, the mucous membrane
of the nose and of the pharynx titillated with a feather
dipped in ammonia, alcohol, vinegar, or lemon juice.
Rhythmic traction of the tongue is effective when car-
ried out as follows : The tongue is seized with a forceps
and kept extended by means of a coarse thread. It is
then pulled out from the mouth sharply and allowed to
reenter after each traction. These movements should
be rhythmic and should be repeated fifteen to twenty
times a minute.
All these efforts should be continued for several
hours. When the patient has finally been revived, he
should be placed in a warm bed. Stimulants such as
wine, coffee, and the like should be administered. If
the head should be congested, local blood-letting should
be resorted to and four or six leeches applied behind
the ears. It should be borne in mind that the various
steps enumerated are to be taken pending the arrival
of a physician.
IMPURITIES OF THE GASES
Most of the coal used in generating producer-gas
contains sulphur. Sulphuretted hydrogen is thus pro-
duced, which mixes with the gas and imparts to it its
characteristic odor. In some gas-generators, purifiers
are employed in which sawdust mixed with iron salts
is utilized, with the result that a combination is formed
with the sulphuretted hydrogen, thereby removing it
from the producer-gas. In other forms of generators
SULPHURETTED HYDROGEN i
73
a more summary method of purification is adopted, so
that traces of sulphuretted hydrogen still remain.
Since this gas attacks copper, the employment of this
metal is not advisable for the following apparatus:
Generator (openings, cock for testing the gas) ; piping
(gas-pressure cocks, drain and pet cocks) ; engine (gas-
admission cock, lubricating joint in the cylinder, valves
and cocks of the compressed-air starting-pipe).
The distillation of coal in generators results in the
formation of ammonia gas. This also has a corrosive
action on copper and its alloys ; but owing to its great
solubility, it is eliminated by the waters of the " scrub-
ber " and does not reach the engine.
PRODUCTION AND CONSUMPTION
The quantity of gas produced in most generators
varies from 6.4 to 8.2 pounds per cubic foot of raw coal
burnt in the generator. The engine consumes per
horse-power per hour 70 to 115 cubic feet of gas, de-
pending upon its richness.
CHAPTER XII
PRESSURE GAS-PRODUCERS
As we have already seen, producer-gas as a fuel for
engines may be generated in two kinds of apparatus, the
one operating under pressure, and the other by suction.
Dowson Gas-Producers. The first pressure-gen-
erators were introduced by Dowson of London and
necessitated installations of quite a complicated nature.
Later improvements made by the designers contrib-
uted much to the general employment of their system.
Many installations varying from 50 to 100 horse-
power and more may be found in the United Kingdom,
all of them made by Dowson. Indeed, for a long time
the name of Dowson was coupled with producer-gas
itself. The Dowson system necessitates the utilization
of anthracite or of comparatively hard coal, such as
that mined in Wales and Pennsylvania. Owing to the
necessity of employing this special quality of coal the
Dowson system and the systems that sprang from it
were burdened with cooling, washing, and purifying
apparatus, which complicated the installations to such
an extent that they resembled gas works. The genera-
tor that took the place of the retort was fed with air
and steam, blown in under pressure, necessitating the
employment of a boiler. Furthermore, the production
174
DOWSON GAS-PRODUCERS
'75
of the gas under pressure necessitated the use of a gas-
ometer for its collection before it was supplied to the
engine-cylinder. Such installations were evidently
costly, and were, moreover, difficult to maintain in
proper working order. Nevertheless, there are many
cases in which they must be industrially employed.
THE GENERATOR
177
Among these may be cited works in which producer-
gas is employed as a furnace fuel or as a soldering or
roasting medium. Still other cases are those in which
the producer-gas must be piped to some distance from
a central generating installation to various engines,
in the manner rendered familiar in gas-lighting prac-
tice.
Most pressure gas-generators have been copied from
the original type invented by Dowson. These include
a generator in which the gas is produced; an injector
fed by a boiler; a fan or a compressor by means of
which a mixture of steam and air is blown under the
generator-furnace; washing apparatus termed " scrub-
bers"; gas-purifying apparatus; and a gas-holder
(Fig. 77).
Generators. The generator consists of a retort made
of refractory clay, vertically mounted, and cylindrical
or conical in form. This retort is protected on its ex-
terior by a metal jacket with an intermediate layer of
sand which serves to reduce the heat lost by radiation.
The fuel is charged through the top of the retort, which
is provided with a double closure in order to prevent
the entrance of air during the charging operation. The
generator rests on a grid arranged at the base of the
retort, upon which grid the ashes fall. The outlet of
the injector-pipe opens into the ash-pit, and this injector
constantly supplies a mixture of steam and air. The
mixture is generally superheated by passing it through
a coil arranged in the fire-box of the boiler, in the gen-
erator, or in the outlet for burnt gases. Sometimes the
178 GAS-ENGINES AND PRODUCERS
air is subjected to a preliminary heating by recuperat-
ing in some way the waste heat of the apparatus.
The chief features in the arrangement of generators
which have received the attention of manufacturers are
the following: Good distribution of the fuel in charg-
ing; easy descent of the fuel; reduction of the destruc-
tive action of the clinkers on the walls ; means for clean-
ing the grate without interfering with the generation of
gas; prevention of leakage. Many devices have been
employed to fulfil these requisites.
A perfect distribution of the fuel during charging is
attained chiefly by the form of the hopper, and of its
gate, which is generally conical. In most apparatus
the gate opens toward the interior of the generator, and
the inclination of its walls causes a uniform scattering
of the fuel in the retort. It is all the more necessary to
disperse the fuel in this manner when the cross-section
of the retort is small compared with its height.
The facility of the fuel's descent is dependent largely
upon the nature and the size of the coal employed.
Porous coal gives better results than dense and compact
coal. It is therefore preferable to employ screened
coal free from dust in pieces each the size of a hazel-
nut. The various sections given to the interior, includ-
ing as they do cylindrical forms, truncated at the sum-
mit or the base, partially truncated toward the base
and the like, would lead to the conclusion that this
question is not of the importance \vhich some writers
would have us believe. Still, it must be considered that
if the fuel drops slowly, its prolonged detention within
CLEANLINESS
179
the walls of the hopper and its transformation into
fusible slag may result in a disintegration of the re-
fractory lining of the furnace.
The quantity of steam injected, greater or less, ac-
cording to the nature of the fuel, renders it possible to
obtain friable slags and consequently to prevent grave
injury to the retort. Red-ash coal is in general fusible,
containing as it does some iron. Its temperature of
fusion varies between 1,832 to 2,732 degrees F.
Cleanliness is most important so far as the opera-
tion of the generator is concerned. It should be pos-
sible to scrape the generator during operation without
changing the composition of the gas, when the incan-
descent zone is chilled, or an excess of air is introduced,
or the steam-injector be momentarily thrown out of
operation. Mechanical cleaners with movable grates
or revolving beds have the merit of causing the ashes
to drop without interfering with the operation of the
apparatus. The same meritorious feature is character-
istic of ash-pits having water-sealed joints.
Pressure gas-generators need not be as perfectly gas-
tight as suction apparatus. Leakage of gas, which is
usually manifested by a characteristic odor, results in a
loss of consumption and renders the air unfit to breathe.
A generator should be provided in its upper part
with openings through which a poker can easily be in-
troduced in order to shake up the fuel and to dislodge
the clinkers which tend to form and which cause the
principal defects in operation, particularly with fuels
that tend to swell, cake, and adhere to the furnace walls
i8o GAS-ENGINES AND PRODUCERS
when heated. Many apparatus, moreover, are pro-
vided with lateral openings having mica panes through
which the progress of combustion can be observed
(Fig. 79).
Air-Blast. The system by which air and steam are
FIG. 79. Fichet-Heurtey producer with rotating bed-plate.
injected necessitates the employment of a steam-boiler
of 75 pounds pressure. This method of blowing, which
is rather complicated, has the disadvantage of varying
BLOWERS: THEIR NECESSITY 181
in feed with the pressure of the steam in the boiler,
which pressure is not easily maintained at a given num-
ber of pounds per square inch. Moreover, when more
or less resistance is offered by the fuel in the generator
the quantity of air which is injected is likely to be
diminished in quantity while the quantity of steam re-
mains the same. The result is a change in speed which
follows from the modification of the proportions of the
two elements. For these reasons some manufacturers
FIG. 80. Koerting blower.
have resorted of late years to the employment of fans
.and blowers.
Blowers. The fans or blowers employed vary con-
siderably in arrangement. Most of them are based on
the Koerting system (Fig. 80), and comprise essentially
(i) a tube through which the steam is supplied under
pressure, and (2) a cylindro-conical blast-pipe. The
tube is placed in the axis of the blast-pipe at its outer
opening. As it escapes under pressure the steam is
caught in the blast-pipe and draws with it a certain
quantity of air, which can be regulated. It is important
that these injection blowers should operate in such a
manner that the pressure and the feed of air and steam
can be controlled.
Fans. Mechanical blowers have the advantage of
1 82 GAS-ENGINES AND PRODUCERS
dispensing with the employment of steam under pres-
sure and the consequent installation of a boiler (Fig.
78) . Driven by the engine itself or from some separate
source of power, these apparatus are easily placed in
position, require no great amount of attention, and util-
ize but little energy. They are either of the centrif-
ugal type or of the rotary type, exemplified in the Root
blower (Fig. 81). The latter system has the advantage
FIG. 81. Root blower.
of high efficiency, and of enabling comparatively high
pressures 19 to 27 inches of water to be attained,
which, however, are used only for special fuels, such
as lignite, peat, and the like. The air supplied by the
blower, before reaching the fire-box, is superheated,
either before or after it is charged with steam.
Compressors. In some installations air is supplied
by compressor under the high pressure of 70 to 90
pounds per square inch, and seem well adapted to the
production of a gas of good quality. Moreover, neither
EXHAUSTERS
'83
tar nor ammoniacal waters are produced. The Gardie
producer may be considered typical of this class of ap-
paratus (Fig. 82). The chief feature of this producer
is to be found in simple washing and purifying appara-
tus. It may be well to state here that the compression
of air at high pressure occasions some complications,
and a considerable expenditure of power.
FIG. 82. Gardie producer.
Exhausters. Some designers have invented devices
which draw gas into the generator whence it is sup-
plied to the engines, these suction apparatus being
connected with the blowers or used separately. But
with the exception of a few special instances, such ar-
rangements are not widely used at least not for the
production of motive power alone.
Whatever may be the arrangement employed for the
1 84 GAS-ENGINES AND PRODUCERS
introduction of a mixture of air and steam under the
grate of the generator, the blast-pipe as a general rule
discharges toward the center of the apparatus. Still, in
large producers it becomes desirable to provide a means
for varying the quantity of air and steam within wide
limits so as to regulate the heat of the fire. For that
reason several outlets are symmetrically arranged be-
low the fuel.
Washing and Purifying. In pressure producers
FIG. 83. Sawdust purifier.
the gas is generally washed and purified with much
more care than in suction apparatus. Given a sufficient
pressure, the gas can be driven through the different
apparatus and the spaces between the material which
they contain without any difficulty. The gases emerge
from the generator highly heated, and this heat is used
either to warm the injection water or to generate the
steam fed to the furnace. The gases then enter the
WASHING AND PURIFYING 185
* 9
washing apparatus, which most frequently consists of
a succession of contrivances in which the gas is washed
either by causing it to bubble up through the water, or
by subjecting it to superficial friction against a sheet of
water, or by systematically circulating it in a mass of
continuously besprinkled inert material. The object of
washing is to remove the dust contained in the gas and
FIG. 84. Moss or fiber purifier.
to precipitate it in the form of a slime which can be re-
moved by flushing.
Physical purification thus begun is completed by
passing the gas through a filtering bed consisting of
fiber, sawdust, or moss ( Figs. 83 and 84) . Chemical puri-
fication, if it is necessary, is effected by means of cal-
cium hydrate, iron oxide, or, still better, by a mixture
of lime and iron sulphate. This filtering material must
necessarily be renewed after it is exhausted.
1 86 GAS-ENGINES AND PRODUCERS
Gas -Holder. The gas-holder is composed essen-
tially of a tank and a bell. Sometimes, for the purpose,
of simplifying the apparatus, the tank is so arranged as
FIG. 85. Combined gas-holder and washer.
to take the place of a washer or scrubber (Fig. 85).
The bell should be provided with mechanism which,
when the bell is full, automatically diminishes or stops
the generation of gas. It is advisable to provide the
GAS-HOLDER DESIGN 187
bell with a blow or flap valve opening toward the inte-
rior. If, therefore, it should happen that the gas sup-
ply is cut off while the engine still continues to run,
the suction of the engine will not draw the water from
the tank of the gas-holder.
When engines are employed the horse-power of which
does not exceed 50, it is sometimes customary to use
the water of the tank (placed at a higher elevation than
the engine) to cool the cylinder. In this manner the
cost of installing special reservoirs is saved. If such
an arrangement be employed, however, the quantity of
water contained in the tank should be at least double
that ordinarily contained in reservoirs. If this precau-
tion be not observed, the water may become excessively
heated and expand the gas in the bell.
The volume of the bell of the gas-holder should
preferably be not less than about 3 cubic feet per effec-
tive horse-power of the engine to be supplied. Under
these circumstances the bell acts as a pressure-regulator,
assures a sufficient homogeneity of the remaining gas,
and renders it possible to supply the engine during the
short intervals in which it is necessary to stop the blast
to poke the fire. But if the engine consumes 60 to
80 cubic feet of producer-gas per horse-power per
hour, the bell must be very much larger in size if the
generation of gas is to be checked for some time
It may be well to recall here that coal is not the only
fuel which lends itself to the generation of gas suitable
for driving engines, but that some generators are able to
utilize lignite, peat, and the like. In others, straw,
1 88 GAS-ENGINES AND PRODUCERS
wood, shavings and sawdust, tannery waste, and other
organic matter is burnt with an efficiency very much
higher than that which they would give in the fire-
boxes of steam-boilers.
Lignite and Peat Producers. Lignite and peat
generators (Fig. 86) cannot operate on the suction
principle because of the resistance offered to the pas-
sage of gas by the layer of fuel. This resistance is con-
siderable and extremely variable. Consequently, lig-
FIG. 86. Otto Deutz lignite-producer.
nite and peat generators must operate on the pressure
principle by utilizing a blast of air or a steam injector,
depending upon the amount of water contained in the
lignite. As a general rule a Root blower operating at
a pressure of 8 to 27 inches of water, depending upon
the quality of the lignite, is employed. These genera-
tors are not to be recommended for powers less than
50 horse-power, for the cost of the apparatus becomes
too great.
LIGNITE AND PEAT PRODUCERS 189
, 9
The best lignite is that which, after combustion,
leaves a fine ash and no agglomerated clinker. Lig-
nite has the peculiarity of forming dust which ignites
very easily when air is admitted into the generator.
For this reason the generator should not be scraped
during operation, in order to avoid the production of
a flame which may escape from the apparatus.
The scrubber is simply a column without coke,
and is provided with an interior sprinkler. The
coke is too rapidly clogged with tar. Much of
this tar is deposited in a chamber which precedes the
gas-holder. Several quarts of tar may be tapped from
the chamber daily.
The gas-holder serves merely to regulate the pro-
duction of gas. The pipes leading to the engine should
be cleaned several times each month, in order to re-
move the thin layer of tar which is deposited within
them.
There are many kinds of lignite, and the gas-genera-
tor should be constructed to meet the peculiar require-
ments of the variety employed. The layer of fuel
should be such in thickness that the gas as it emerges
from the generator has a temperature of about 77
degrees F. This is the temperature of the gas which
leaves the scrubber in the case of anthracite-generators.
If the lignite contains much water, the greater part is
retained in the washer by the gas in the form of drops.
Sometimes the water drips through the grate of the
generator. Lignite-generators may also be operated
with peat, and even with town refuse, with slight modi-
1 9 o GAS-ENGINES AND PRODUCERS
fications. The consumption per horse-power per hour
is 3.3 pounds of lignite containing 2,400 calories
(9,424.9 B. T. U.). In order to generate the same
power with a boiler and steam-engine, 8.8 pounds would
be required. An engine driven unloaded with fuel
furnished by a lignite-generator will consume 50 per
cent, of the weight of the fuel required at full load.
This depends upon the proportion of water contained
in the lignite and on losses of heat by radiation from the
generator. In street-gas engines running without load,
the absorption is 20 per cent., in anthracite-generators
40 per cent, of the consumption at full load.
Passing now to the utilization of wood, of which
something has already been said in Chapter XI, two
entirely distinct processes are successfully employed in
apparatus of the Riche type, these processes depending
upon the form of the wood used whether, in other
words, the wood be consumed in the form of sticks or
blocks or in the form of chips, sawdust, bark, and the
like, all of them the wastes of factories in which wood
is used.
Distilling -Producers. If the wood consists of logs,
it is burnt in a generator comprising a fire-box and a
distilling retort. The fire-box is charged with ordinary
coal which serves to heat the retort to redness. The
wood is discharged through the top of the retort, and
the gas, produced by the distillation, escapes through
the bottom and passes to the washing apparatus. The
base of the retort is heated to about 1,652 degrees F.,
while at the top this temperature is reduced to 752 de-
or THE
UNIVERSITY
OF
DISTILLING-PRODUCERS
grees F. The wood thus treated is transformed into
charcoal, which is a by-product of some value.
The lower part of this cast retort (Fig. 87) is lined
with charcoal, the residue of previous distillations.
FIG. 87. Rich distilling-producer.
The wood which is introduced in the upper part of
the retort is distilled in the chamber. The retort is
held by its own weight in a socket on the foot, which
socket is lined with a special refractory cement, made
of silicate, asbestos forming the joint. The products
1 92 GAS-ENGINES AND PRODUCERS
of combustion, issuing from the furnace, pass by way
of the flue to the lower part of the casing, and raise
the temperature of the retort and the charcoal it con-
tains to that of a cherry red (1,652 degrees F.). These
products of combustion then float to the upper part of
the casing and heat the top of the retort to a temperature
of about 752 degrees F., in which part the wood or the
wooden waste to be distilled is enclosed. Thence the
products of combustion pass through a horizontal flue,
provided with a damper, into a collecting flue by which
they are led to the smoke-stack. The products of distil-
lation formed in the chamber, having no outlet at the
top of the retort, must traverse the zone filled with in-
candescent carbon. The condensible products are con-
ducted as permanent gases (carbonic-acid gas in the
state of carbon monoxide) and are collected in the re-
ceptacle, after having passed the funnel and the bell of
the purifying apparatus.
A gas-furnace is formed by grouping in a single mass
of masonry a certain number of elements of the kind
just described. It is essential that the retorts should be
vertically placed, that they be made only of cast metal
and not of refractory clay, and, finally, that their diam-
eter be not much more -than 10 inches, which size
has been found most expedient in practice. The gas
collected in the bell or in one or more of the receptacles
passes into the gasometer and then into the service pipes.
If 2.2 pounds of wood be distilled by burning in the
furnace f of a pound of coal of average quality or 2.2
pounds of wood (either sawdust or waste), 24.5 to 28
WOOD-PRODUCERS 193
cubic feet of gas will be generated having a thermal
value of 3,000 to 3,300 calories per cubic meter (11,904
to 13,094 B. T. U. per 35.31 cubic feet), and a residue
44 pounds of charcoal will be left.
In practice only the wood of commerce containing in
the green state 20 to 40 per cent, of water, depending
upon the variety, is used. Hornbeam contains the least
water (18 per cent), while elmwood and spruce con-
tain the most (44 to 45 per cent).
The blast apparatus of the generator being started,
the gas is supplied under pressure. By reason of its
permanent composition and its richness, it is an excel-
lent substitute for street-gas in incandescent lighting,
a good furnace fuel reducing agent.
Producers Using Wood Waste, Sawdust, and the
Like. If waste wood in the form of shavings, sawdust,
straw, bark, and the like, should be employed, a still
higher efficiency is obtained with self-reducing genera-
tors of the Riche type.
Combustion-Generators. In combustion-generators
(Fig. 88) the fuel is burnt and not distilled. The gen-
erator comprises two distinct elements. The first is the
generator proper, in which the combustion takes place.
Upon it is placed a hopper or fuel supply box. The
second element is the reducer, in which by an independ-
ent process the reduction of the carbonic-acid gas, the
dissociation of the steam, and the transformation of the
hydrocarbons takes place. The generator is provided
at its base with a grate having oblique bars in tiers,
which grate is furnished with a channel in which the
194 GAS-ENGINES AND PRODUCERS
water for the generation of hydrogen flows. On a level
with this grate, at the opposite side, is a flue com-
municating with the reduction column of coke. The
incandescent zone of the generator should not extend
above the level of the grate. Instead of passing through
the layers of fresh fuel and out by way of the top, the
gas generated flows directly into the reduction column
where it heats the coke to incandescence. The high
temperature to which the coke is subjected, coupled
with the injection of air, effects useful reactions. This
FIG. 88. Riche combustion-producer.
additional air, however, is not used if the fuel is free
from all products of distillation.
Experience has shown that gas of 1,000 to 1,100 cal-
ories per cubic meter (3,968 to 4,365 B. T. U. per 35.31
cubic feet), which heat content is necessary to develop
one horse-power per hour, can be obtained with 3.96
pounds of wood in the form of shavings and sawdust
containing 30 per cent, of water. The corresponding
quantity of coke consumed in the reduction column is
INVERTED COMBUSTION
insignificant, and may be placed at about 0.112 pounds
per horse-power per hour.
It has been proven in actual practice that, both in
the distilling and combustion types of apparatus, the
wood, either in the green state or in the form of saw-
mill waste, may contain as much as 60 per cent, of
water. Either of the two systems can be operated under
pressure with an air-blast, in which case a gas-holder
and bell must be employed. The gas as it passes from
the generator to the gas-holder is conducted through a
cooler and washer and through a moss filter, which
removes traces of the products that may have escaped
the distillation.
Inverted Combustion. With a few exceptions the
pressure-generators which have been described, as well
as suction gas-producers which will be later discussed,
are fed with anthracite coal or with coke. They cannot
be operated with moderately soft or bituminous coal.
For this reason they limit the employment of producer-
gas engines. Manufacturers have long sought genera-
tors in which any fuel whatever can be consumed.
Among the producers which seem to overcome the
objections cited to a certain degree, are those which are
based on the principle of inverted combustion. These
apparatus embody the ideas of Ebelmen, the products
of distillation being decomposed by passing them over
layers of incandescent fuel.
Many writers place in the class of inverted combus-
tion producers, apparatus of the Riche, Thwaite, and
Duff type, in which this idea is also carried out. Riche
FIG. 89. Deschamps inverted-combustion producer.
196
INVERTED-COMBUSTION
197
employs an independent incandescent mass to reduce
the products of distillation of another mass. Thwaite
employs two vessels which serve alternately as distilling
FIG. 90. Fange-Chavanon inverted-combustion producer.
retorts and reducing columns. Duff draws in the prod-
ucts of distillation for the purpose of blowing them
under the fire. All these generators can hardly be said
to be of the inverted combustion type.
198 GAS-ENGINES AND PRODUCERS
The generators of Deschamps (Fig. 89) and of
Fange and Chavanon (Fig. 90), on the other hand, are
producers in which the combustion is really inverted,
and which are worked continuously. The air enters at
the upper part of the retort, passes through the entire
mass of fuel, carrying with it the distilled volatile prod-
ucts, and when the mixture reaches the incandescent
zone, chemical reactions occur that result in the pro-
duction of a gas entirely free from tar and other im-
purities.
CHAPTER XIII
SUCTION GAS-PRODUCERS
THE high cost and the complicated nature of the
pressure gas-generators which have just been discussed
have led manufacturers to attempt in some other way
the generation .of producer-gas intended for operating
motors.
Several inventors, among whom we will mention
Benier and A. Taylor (in France), made some praise-
worthy although not immediately very successful at-
tempts to simplify the manufacture of producer-gas.
Advantages. In these systems the suction occa-
sioned by the motor itself has taken the place of a forced
draft, produced in the generator by an air-injector or a
fan, so that the gas, instead of being stored under pres-
sure in a gas-holder, is kept in the apparatus under a
pressure below that of the atmosphere.
As the device for producing a draft by means of
boiler pressure or of a fan, and the gas-holder, are dis-
pensed with, the result is a saving, first in the cost of
installation, consumption, and floor space. Further-
more, the cooler and washer are supplanted by a single
scrubber.
Manufacturers have succeeded in devising apparatus
remarkable for the simplicity of the processes employed
199
200 GAS-ENGINES AND PRODUCERS
and yielding economical results which would never be
obtained with pressure-generators employing gas-hold-
ers and boilers, considering that the boiler alone calls
for a consumption of from 15 to 30 per cent, of the total
amount of coal used for making the gas.
The best results obtained by the author with pressure
gas-producers have indicated a consumption of not
much less than i to 1% pounds of anthracite per horse-
power per hour at the motor, while with suction-gen-
erators, under similar conditions and with the same
grade of fuel, he has repeatedly found a consumption
of from T 9 Q- pounds per effective horse-power per hour.
In either case, the gas obtained developed between
1,100 and 1,300 calories (4,365 and 5,158 B. T. U.
per 35.31 cubic feet) if produced from anthracite yield-
ing from 7,500 to 8,000 calories (29,763 to 31,746-
B. T. U.) per 2.2 pounds.
The suction apparatus will also work very well with
inferior coal containing up to 6 to 8 per cent, of volatile
matter and from 8 to 10 per cent, of ash. This great
advantage added to all the others explains the favorable
reception which European manufacturers at once gave
to suction-producers. The petroleum engine itself will
find a serious competitor in the new system.
As regards the possibility of employing suction gas-
generators with respect to the somewhat peculiar prop-
erties of the fuel, it may be said at the outset that coke
from gas works yielding from 6,000 to 6,500 calories
(22,911 to 24,995 B. T. U.) and also charcoal are per-
fectly available.
QUALITIES OF FUEL 201
,
One horse-power per hour is obtained with a con-
sumption of i.i to 1.3 pounds of coke.
Blast-furnace coke may be used in case of need, but
its employment is not to be recommended on account of
the sulphides it contains, which sulphides, being car-
ried along by the gas, are liable to form sulphuric acid
with the steam, the corrosive action of which would
soon destroy the cylinder and other important parts of
the engine.
Qualities of Fuel. Anthracite coal is, upon the
whole, so far the best available fuel for generators.
However, it should possess certain qualities which will
now be briefly indicated.
In suction gas-generators, above all, it is important
that no harmful resistance should be opposed to the
passage of the air and of the gas produced. It is there-
fore necessary to employ coal of a size that will an-
swer the foregoing condition, without being too expen-
sive.
The size of the pieces, to a certain extent, determines
the price; and with coal of the same properties, pieces
i.i to 2 inches may cost 1.4 of the price for the ordinary
size of 0.59 to 0.98 inches, which is very well adapted
for gas-generators. This is the size of a hazel-nut.
Moreover, it will be advisable to select the dryest
coals, containing a minimum of volatile matter and hav-
ing no tendency to coke or to cohere, in order that the
volatilized products may not by distillation obstruct the
interstices through which the gases must pass. For the
same reason coal which breaks up and becomes pulver-
202 GAS-ENGINES AND PRODUCERS
ized under the action of the fire is not to be recom-
mended. The coal should also be such as to avoid the
formation of arches which would interfere with the
proper settling of the fuel during its combustion. It
may be stated as a rule that, with coal that does not co-
here, the content of volatile matter should not exceed
5 to 8 per cent.
Coal which contains more than 10 to 15 per cent,
of ash should not be used, for the reason that it chokes
up and obstructs generators in which the dropping and
discharge of the ashes is done automatically, a fact
which should not pass unnoticed. The furnace cannot
be cleaned safely with a fire of this kind, where com-
bustion takes place in an enclosed space, without hin-
dering the production of gas. Here again a point may
be raised very much in favor of suction gas-producers.
In a good generator, the ash-pit can be cleaned and the
fire stoked without interrupting the liberation of the
gas drawn in and without appreciably impairing the
quality of the gas. These considerations are of im-
portance so far as the gas-generator itself is concerned.
Other conditions which should be noticed affect the
engine fed by the generator, the grade of coal used, and
the purification of the gas obtained from it.
Unless special chemical cleaners and purifiers are
employed, thereby complicating the. plant, the coal
utilized should yield as little tar as possible during dis-
tillation; for the tendency of the tar to choke up the
pipes and to clog the valves is one of the chief causes of
defective operation of producer-gas engines.
QUALITIES OF FUEL 203
Tar changes the proper composition of the explosive
mixture. When it catches fire in the cylinder it causes
premature ignition, which is so dangerous in large en-
gines.
From what has been said in the foregoing, it follows
that, in the present state of the art, the satisfactory
operation of gas-generators depends no longer on the
use of pure anthracite, such as Pennsylvania coal in
America and Welsh coal in England, containing an
amount of carbon as high as 90 to 94 per cent, and hav-
ing a thermal value of 33,529 B..T. U. On the con-
trary, good dry coal yielding from 29,763 to 31,746
B. T. U. is quite suitable for the generation of pro-
ducer-gas.
A final, practical advantage which speaks in favor of
a generator and motor plant as compared with a steam-
engine, is the small amount of water required. Apart
from the water used for cooling the engine, which may
be used over and over again if cooled, any water,
whether it forms scale or deposits, may be employed for
cooling and washing the gas in the scrubber.
According to the author's personal experience, an
average of 3.3 gallons of water per effective horse-
power per hour is sufficient for this purpose. This is
about one-half of the amount required by a non-con-
densing slide-valve engine of from 15 to 30 horse-
power. The difference in the consumption of water is
quite important in city plants, where water is rather
expensive as a rule.
General Arrangement. A suction gas-generator
204 GAS-ENGINES AND PRODUCERS '
plant of the character we have been discussing is shown
in Fig. 91.
The apparatus A is the generator proper, in which
combustion takes place. The gas produced passes into
the apparatus B through a series of tubes, to be con-
veyed to the washer C. In the apparatus JB, which is
the vaporizer, the water admitted at the top under at-
mospheric pressure is vaporized by contact with a series
of tubes, heated by the gas coming from the generator.
FIG. 91. Engine and suction gas-producer.
The steam, together with air, is drawn into the lower
part of the generator to support combustion. This vapor-
izer is provided with an overflow for the outlet of, the
water which has not been vaporized. The producer-
gas pipe which leads from the vaporizer to the washer
has a branch Z), for the temporary escape to the atmos-
phere of the gas produced before and after the opera-
tion of the engine. In the washer, as the drawing
shows, the gas enters at the bottom and leaves at the top
to pass to the gas expansion-chamber E and thence to
the motor. The gas thus passes through the body of
GENERAL ARRANGEMENT 205
t
coke in the opposite direction to the wash water, which
then flows to the waste-pipe. The coke and the water
free the gas not only from the dust carried along, but
from the ammonia and other impurities contained in
the gas.
When firing the generator, a small hand ventilator
G is used for blowing in air to fan the fire. The gas
obtained at first, being unsuitable for combustion, is
allowed to escape through the branch D. After in-
jecting air for about 10 to 15 minutes, the engine can
be started after closing the branch D. The suction of
the engine itself will then gradually bring about the
proper conditions for its regular running, and after a
quarter of an hour or half an hour the gas is rich
enough to run the engine under a full load.
The apparatus just described is the original type,
upon which many improvements have been made for
the purpose of securing a uniform gas production and
of diminishing the interval of time elapsing between
the firing of the generator and the running of the en-
gine under a full load.
Each of the elements of this apparatus to wit, the
generator, vaporizer, superheater, and washer 4iave
been modified and improved more or less successfully
by the manufacturers; and in order that the reader may
perceive the merits and the drawbacks of the various
arrangements adopted, the most important ones will be
separately discussed.
Generator. With respect to the general arrangement
of parts, generators may be divided into two classes :
206 GAS-ENGINES AND PRODUCERS
First. Generators with internal vaporizers, such as.
the Otto Deutz and Wiedenfeld generators.
FIG. 92. Old type of Winterthur producer.
Second. Generators with external vaporizers, such
as the Taylor, Bollinckx, Pintsch, Kinderlen, Benz,
Wiedenfeld, Hille, and Goebels generators.
CONSTRUCTION OF GENERATOR 207
,
Cylindrical Body. The generator consists essen-
tially of a mantle made of sheet-iron or cast-iron and
containing a refractory lining which forms a retort, a
grate, and an ash-pit. In the small size apparatus the
cast-iron mantle is often used, whereas in large sizes
the mantle is made of riveted sheet-iron so as to reduce
its weight and its cost. In the latter case the linings
are securely riveted or bolted.
The Winterthur generator (Figs. 92 and 93), the
Taylor generator (Fig. 94), and the Benz generator
(Fig. 97), are made of cast-iron; the Wiedenfeld gen-
erator (Fig. 95), the Pintsch generator (Fig. 96), are
made of sheet-iron; the Bollinckx (Fig. 98) is made
partly of sheet-iron and partly of cast-iron.
The different parts of a generator, if made of sheet-
iron, are held together by means of angle-irons form-
ing yokes, and a sheet of asbestos is interposed. If the
parts are made of cast-iron, they are connected after the
manner of pipe-joints and packed with compressed as-
bestos. This latter way of assembling the parts pre-
sents the advantage of allowing them to be dismem-
bered readily. Therefore, it allows the several parts to
expand freely and facilitates the securing of tight joints.
This last consideration is exceedingly important, par-
ticularly for the joints which are beyond the zone in
which the distillation of the fuel takes place. Any en-
trance of air through these joints would necessarily im-
pair the quality of the gas, either by mingling there-
with, or by combustion. The air so admitted would
also be liable to form an explosive mixture which might
FIG. 93. New type of Winterthur producer.
208
!
OH
1
PQ
o^
o
210
SUCTION GAS-PRODUCERS
211
become ignited in case of a premature ignition of the
cylinder charge during suction or through some other
cause.
Refractory Lining. The interior lining of the gen-
erator should be made of refractory clay of the best
FIG. 99. Lencauchez producer.
quality. It would seem advisable, in order to facilitate
repairs, to employ retorts made of pieces held together
instead of retorts made of a single piece. In the first
case the assembling should preferably be made by
means of refractory cement, and the inner surface
212 GAS-ENGINES AND PRODUCERS
should be covered with a coating so as to form a prac-
tically continuous stone surface.
Some manufacturers, in order to allow for the re-
FIG. 100. Goebels producer.
newal of the part most liable to be burnt, employ at the
bottom of the tank a refractory moulded ring (Len-
cauchez, Fig. 99).
It is always advisable to place between the shell or
GENERATOR DESIGN
213
mantle of the generator and the refractory lining a
layer of a material which is a bad conductor of heat as,
FIG. 1 01. Pierson producer.
for instance, asbestos or sand, in order to avoid as much
as possible loss of heat due to external radiation (Fig.
100).
214 GAS-ENGINES AND PRODUCERS
Grate and Support for the Lining. These parts,
owing to their contact with the ashes and the hot em-
bers, are liable to deteriorate rapidly. It is therefore
indispensable that they should be removable and easily
accessible, so that they may be renewed in case of need.
From this point of view, grates composed of inde-
pendent bars would appear to be preferable. The
clearance between the bars depends, of course, on the
kind of ashes resulting from the different grades of
fuel. It is advisable to design the grate so that the free
passage for the air is about 60 to 70 per cent, of the
total surface.
In generators having a cup-shaped ash-pit, contain-
ing water (Fig. 95), the grate and the base of the re-
tort are less liable to burn than in apparatus having dry
ash-pits. Certain apparatus, such as those of Lencau-
chez (Fig. 99), Pierson (Fig. 101), and Taylor (Fig.
94) , have no grates ; the fuel is held in the retort by the
ashes, which form a cone resting on a sheet-iron base,
easy of access for cleaning and from which the fuel
slides down gradually.
The Pierson generator (Fig. 101) is provided with
a poker comprising a central fork, which is worked
with a lever, in order to stir the fire from below with-
out entirely extinguishing the cone of ashes.
In some apparatus in which a grate is used (Fig. 92),
a space is left between the grate and the support of the
retort. This arrangement has the merit of allowing
only finely divided and completely burnt ashes to pass
to the ash-pit. Moreover, a large surface grate can be
GRATES
2I 5
employed, thus facilitating the passage of the mixture
of air and steam.
The space above mentioned is provided with a clean-
FIG. 102. Kiderlen producer.
ing-door through which cinder and slag may be re-
moved.
In other apparatus the grate rests either on the sup-
port of the refractory lining, as in the old type invented
2i 6 GAS-ENGINES AND PRODUCERS
by Wiedenfeld (Fig. 95), or upon a projection em-
bedded in the lining, as, for instance, in the Kiderlen
(Fig. 102) and Pintsch generators (Fig. 96).
In the Riche apparatus (Fig. 103) there is, besides
the ordinary grate, a grate with tiers on which the fuel
FIG. 103. Riche combustion -producer.
spreads. This grate consists of wide, hollow bars con-
taining water. It should be noted that the apparatus is
of the blower type.
An interesting arrangement is found in Benier's gen-
erator (Fig. 104). This consists of a grate formed of
projections cast around a cylinder which can be turned
about its axis. The finely divided ashes which are re-
BENIER'S GRATE
217
tained in the spaces between these projections are thus
carried into the ash-pit, and those which adhere to the
metal are scraped away by a metallic comb fastened to
x>$$^^S^^
FIG. 104. Benier producer.
the lower part of the apparatus. The " Phoenix " gen-
erator (Fig. 105) is fitted with a grate having a
mechanical cleaning device, worked by a lever from the
outside.
Ash-Pit. The ash-pits are exposed to the destructive
FIG. 105. Phoenix producer.
218
ASH-PITS
219
effects of heat and moisture, and should preferably be
constructed of cast-iron, since sheet-steel is liable to
corrode quickly.
FIG. 106. Otto Deutz producer.
In most apparatus the ash-pit is hermetically sealed,
and the air for supporting combustion enters below the
220 GAS-ENGINES AND PRODUCERS
grate through a pipe leading from the heater or the
vaporizer. This arrangement seems best adapted to
prevent the leakage of gas which tends to take place by
reaction after each suction stroke of the engine.
Ash-pits formed as water-cups, such as the Deutz
(Fig. 1 06), the Wiedenfeld (Fig. 95), and the Bol-
linckx (Fig. 98), are fed by the overflow from the
vaporizer. These ash-pits are themselves provided
with an overflow consisting of a siphon-tube forming a
water-seal.
Besides providing protection to the grate and other
parts by this sheet of water, a larger proportion of the
heat radiated from the furnace is utilized for the pro-
duction of steam which contributes to enrich the gas.
The doors of the ash-pits and their fittings are likewise
exposed to a rapid deterioration.
For this reason these parts should be very strongly
made, either of cast-iron or cast-steel. Furthermore,
they should, at joint surfaces, be connected in an air-
tight manner, which may be attained by carefully fin-
ishing the engaging surfaces of the frame and the door
proper, or by cutting a dovetail groove in one of the
sides of the frame which is packed with asbestos and
adapted to receive a sharp edged rib on the other part.
The pintles of the hinges should also be carefully
adjusted so that the joint members of the door shall re-
main true. Hinges with horizontal axes seem to be
preferable in this respect to those having vertical axes.
As a means of closing the door, the arrangement here
shown (Fig. 107) seems to assure a proper engagement
FIRE-BOX DOORS
221
of the joint surfaces. It consists of a yoke which strad-
dles the door, and which, on the one hand, swings about
the hinge, and on the other hand engages a movable
hoop. A screw, fastened to the yoke, serves to tighten
the door by pressure on its center. This screw can also
be fastened to the end of the yoke (Fig. 108).
It is very advantageous to provide in each door a
hole closed by an air-tight plug, so that in case of
FIGS. 107-108. Fire-box doors.
need a tool may be introduced for cleaning the grate.
In this manner the grate may be cleaned without
opening doors and without causing a harmful entrance
of air.
The door of the furnace, particularly, should be pro-
vided with an iron counter-plate held by hinged bolts
(Fig. 109) ; or, better still, this door^should be so con-
structed that it can be lined with refractory material to
protect it against the radiated heat of the fire.
Charging-Box. Like the other parts of the genera-
tor the construction of which has been discussed above,
the charging-box should be absolutely air-tight.
222 GAS-ENGINES AND PRODUCERS
On account of their greater security, preference
should be given to double closure devices, which form
a sort of preliminary chamber, owing to which the fill-
ing of the generator is made in two operations. The
first operation consists in filling the preliminary cham-
ber after opening the outer door. Upon closing this
outer door, the second operation is performed, which
consists in moving the inner door so as to cause the fuel
in the preliminary chamber to drop into the generator.
FIG. 109. Door with refractory lining.
Stress has been laid on the greater safety of this type of
charging-box for the reason that, with devices having a
single charging-door, a sudden gust of air may rush
in at the time of charging the furnace, and bring about
an explosion very dangerous to the workman entrusted
with stoking the furnace.
The closure is generally simply a removable cover,
or may be a lid swinging about a hinge having a hori-
zontal or vertical axis.
As regards the inner door, which is of great im-
portance, in order to insure an air-tight joint, there are
three chief types of closure:
TYPES OF CLOSURE 223
1. The Lift-Valve.
2. The Slide-Valve.
3. The Cock.
The Lift-Valve. The lift-valve is formed by a disk
of conical or spherical shape moved up and down by
means of a lever having a counter-weight for adjust-
ment. The valve is used in the Winterthur (Fig. 92)
and Bollinckx (Fig. 98) generators.
This device serves as an automatic closure and insures
a tight joint irrespective of wear. Moreover, it presents
the advantage that, at the moment of opening, it dis-
tributes the fuel evenly in the generator; but on .the
other hand, it has the drawback of not allowing the
fuel to be examined or shaken through the charging-
box. In apparatus provided with this kind of valve, it
is therefore advisable to furnish the upper part of the
generator with agitating holes closed by an air-tight
slide.
Slide-Valve. The slide-valve closure consists of a
smooth-finished metallic plate movable below the
charging-box proper. Operated as it is from the out-
side, it is evident that the slightest play, the wearing of
the pivot, or the weight of the charge, will form spaces
between the plate and its seat through which air may
rush in.
Furthermore, the manipulation of the slide-valve
may be interfered with if too much fuel is put in the
generator.
The valve or damper may move parallel to itself or
swing about the operating axis. The Taylor apparatus
224 GAS-ENGINES AND PRODUCERS.
(Fig. 94) and the Benier apparatus (Fig. 104) are
provided with such valves.
The Pintsch generator (Fig. 96) is provided with a
device which, properly speaking, is not a damper, but
which consists of two boxes movable about a vertical
axis and arranged to be displaced alternately above the
shaft to effect the charging. This system effects only
a single closure, but explosions are scarcely to be feared
with an apparatus of this kind, owing to the consider-
able height of fuel contained between the charging
opening and the gas-producing zone.
Cock. The cock is applied particularly in the mod-
ern apparatus of the Otto Deutz Co. (Fig. 106) and
the Pierson generator (Fig. 101). It consists of a large
cast-iron cone, having an operating handle and an
opening. The cone moves in a sleeve formed by the
charging-box.
This arrangement appears to be preferable to the
others on account of its simplicity and of the ease with
which it can be taken apart for cleaning. Moreover,
the fuel can be poked directly through the feed-hopper.
In apparatus provided with a cock, it is advisable to
place on the outside cover a mica pane through which
the condition of the fuel may be examined without
danger.
Feed-Hopper. Below the charging-box is arranged,
as a rule, a hopper tapered conically downward. This
part of the generator should serve only as a storage
chamber for fuel. It can therefore be made of cast-
iron, and has the advantage of being removable, easily
CONNECTION OF PARTS 225
9
replaced, and of allowing ready access to the retort for
the purposes of examination and repair.
The annular space surrounding this feed-hopper gen-
erally forms a chamber for receiving the gas produced,
as in the Winterthur (Fig. 92), the Bollinckx (Fig.
98), and the Taylor apparatus (Fig. 99).
In generators having an internal vaporizing-tank,
this tank itself serves as a feed-hopper, which is the
case in the Deutz apparatus (Fig. 106) and Wieden-
feld generator (Fig. 95).
Connection of Parts. In order to facilitate the
thorough cleaning of the retort, preference is given to
removable charging-boxes and feed-hoppers. These
are features of apparatus of the Bollinckx type (Fig.
98), in which the charging-box is secured to the gen-
erator by means of its yoke and by catches provided
with knobs, and also of apparatus of the Winterthur
kind (Fig. 92), having a charging-box pivoted about
a vertical axis, or apparatus of the Duplex type (Fig.
no), in which the charging-box can swing about a
horizontal hinge.
Air Supply. We have seen that, when starting the
generator, the gas is produced with the aid of a fan.
This fan may be operated mechanically, but is generally
operated by hand.
It is customary to convey the air-blast through a pipe
leading to the ash-pit, as in the Winterthur apparatus
(Fig. 92). Often, however, the air supply pipe is di-
rectly branched on that which leads from the vapor-
izer to the ash-pit, as in the Deutz apparatus (Fig.
226 GAS-ENGINES AND PRODUCERS
106). In this case a set of valves or dampers permits
the disconnection of the fan or its connection with the
ash-pit.
In some apparatus an air inlet is provided imme-
diately adjacent to the ash-pit. This arrangement is
faulty for the reason that it gives rise to gaseous emana-
tions which take place by reaction after each suction
FIG. no. Duplex charging-hopper.
stroke of the engine. Furthermore, it is advisable that
the air supplied below the ash-pit be as hot as possible.
For this reason the employment of preheaters is desir-
able. The dry air forced in by the fan stimulates com-
bustion, and the hot gas produced and mixed with
smoke escapes through a separate flue, generally ar-
ranged beyond the vaporizer and serving as a chimney.
This chimney should in all cases be extended to the
outside of the building, and should never terminate in
AIR SUPPLY
227
a brick chimney or similar smoke-flue. The direct
escape of such gas and smoke through a telescopic
FIG. in. Bollinckx flue
and scrubber.
FIG. 112. Winterthur flue
and air-reheater.
chimney above the charging-box has been generally
abandoned in modern structures.
228 GAS-ENGINES AND PRODUCERS
The escape-pipe mentioned, being branched on the
gas-pipe leading to the engine, should be capable of
disconnection when desired, by a thoroughly tight sys-
tem of closure. For this purpose, some employ a simple
FIG. 113. Otto Deutz flue.
FIG. 114. Benz flue.
cock (Bollinckx, Fig. in), a three-way cock, a set of
cocks, or, still better, a double valve, as in the Winter-
thur apparatus (Fig. 112) and the Deutz apparatus
(Fig. 113). A double seated valve is also used, as is
the case in the Benz generator (Fig. 114).
VAPORIZERS 229
Vaporizer-Preheaters. As has been stated before,
there are vaporizers internal or external, relatively to
the generator.
Internal Vaporizers. The Deutz apparatus (Fig.
1 06), for example, consists of an annular cast-iron tank
mounted above the retort of the generator.
The hot gases given off by the burning fuel travel
around this tank and vaporize the water which it con-
tains. The air drawn in by the suction of the engine
enters through an opening located above the tank,
travels over the surface of the water which is being
vaporized, and thus laden with steam passes to the
ash-pit.
The tank in question is supplied with water by means
of a cock having a sight feed, located on the outside,
and the level is kept constant by means of an overflow
tube leading to the ash-pit. It is well to bend this tube
and to place a funnel on its lower member. The
amount of overflow may thus be regulated.
These vaporizers are simple and take up little room;
but they are open to the apparently well-founded objec-
tion that they heat up slowly and require a considerable
time to produce the steam necessary to enrich the gas,
this being due to the relatively large mass of cast-iron
and the amount of water contained therein.
The Pierson vaporizer (Fig. 101) and the Chavanon
vaporizer (Fig. 115) both consist of an annular tank
forming the base of the generator. Steam is formed
near the outlet of the ashes, which, as has been described
above, leads to the outer air. The development of
2 3 o GAS-ENGINES AND PRODUCERS
steam is regulated by mechanical means controlled by
the suction of the engine.
External Vaporizers. External vaporizers are gen-
FIG. 115. Chavanon producer.
erally formed by a cylinder with partitions constituting
two series of chambers. In one of these the hot gases
VAPORIZERS
231
from the generator travel, and in the others the water to
be vaporized is contained.
Tubular Vaporizers. Different types of tubular
vaporizers are manufactured. The vaporizer with a
series of tubes, as in Taylor's apparatus (Fig. 116),
FIG. 116. Taylor vaporizer.
FIG. 117. Deutz vaporizer.
Deutz's old model (Fig. 117), or with single tube like
Pintsch's generator (Fig. 118), is formed by three com-
partments separated by two tube sheets or by plates
which are connected by tubes.
In some cases the gases pass within the tubes, while
the water to be vaporized surrounds them; as in the
232 GAS-ENGINES AND PRODUCERS
Pintsch apparatus (Fig. 118), and Taylor apparatus
(Fig. 116), Benz (Fig. 119), and Koerting genera-
tors (Fig. 120).
In other cases, the water lies inside and the gas out-
FIG. 118. Pintsch vaporizer and scrubber.
side. In this latter case, a longitudinal baffle is em-
plpyed to compel the gases to heat the tubes in their
whole length, as in the Deutz producer (Fig. 1 17) . In
a general way it may be said that such a series of tubes
VAPORIZERS
2 33
presents the disadvantage of becoming clogged up
rapidly by the deposit of lime salts contained in water.
If the set of tubes consists of fire-tubes, the deposit
will form on the outer surface, that is, on a portion not
accessible for cleaning. From this point of view,
FIG. 119. Benz vaporizer.
FIG. 120. Koerting vaporizer.
water-tubes are preferable, as they allow the deposit or
scale to be removed through the tubular heads or plates.
On the other hand, such water-tubes have the draw-
back that their exterior surfaces are readily covered
with pitch and soot. The tubular vaporizers of the
234 GAS-ENGINES AND PRODUCERS
Field type (Bollinckx, Fig. 98) are composed of a
single sheet-iron tube or shell, in which the tubes are
arranged, dipping into a chamber through which the
hot gases pass. This arrangement insures a rapid pro-
duction of steam, but the Field tubes are even more
liable than the others to become covered with deposits.
It will be seen that these types of vaporizers should
all present the following features: easy access, small
quantity of the body of water undergoing vaporization,
and large heating surface with small volume.
The use of copper or brass tubes should be strictly
avoided, as they would be quickly corroded by the
action of the ammonia and hydrogen sulphide con-
tained in the gas.
Partition Vaporizers. Partition vaporizers com-
prise a cylindrical shell, generally made of cast-iron
and having a double wall in which the water to be
vaporized circulates. The gas coming from the gen-
erator passes into the central portion, where it comes in
contact with a hollow baffle, also containing water
(Wiedenfeld, Fig. 121). Vaporizers of this kind are
strong, simple, and easily cleaned.
Operation of the Vaporizers. The general pur-
pose of vaporizers, whatever their construction may be,
is to produce steam under atmospheric pressure, by
utilizing the heat of the generator gases immediately
after their production, or, as in the Chavanon system,
by utilizing the heat radiated from the furnace.
The air drawn by the engine through the generator
generally passes through the vaporizers and becomes
VAPORIZERS
235
laden with a certain amount of steam which it carries
along. The amount thus taken up depends chiefly upon
the temperature and the amount of gases coming from
the generator, so that the greater the amount drawn into
FIG. 121. Wiedenfeld vaporizer.
the engine, the more energetic will the vaporization be,
and the richer the gas will become. It will be under-
stood that when a generator is working at its maximum
production, the interior temperature is highest and
most favorable to the decomposition of the largest
amount of steam.
236 GAS-ENGINES AND PRODUCERS
It follows that with the very simple vaporizers which
have been reviewed, a practically automatic regulation
is obtained. However, some manufacturers have
deemed it advisable to regulate the amount of steam
more accurately, and to make it exactly proportionate
to the power developed by the motor. Thus in the
Winterthur gas-producer (Figs. 92 and 1 12) the manu-
facturers have omitted the vaporizer proper, and use
instead an air-heater and a super-heater for air and
steam.
The heater is formed by a cast-iron box having two
compartments, through one of which the hot gases from
the generator pass, while in the other the air intended
to support combustion travels. At the inlet of the
super-heater a pipe terminates, which feeds, drop by
drop, water supplied by a feed device to be described
presently. This water is vaporized immediately upon
contact with the wall of the super-heater and is carried
along with the air contained in it.
The super-heater comprises a hollow ring-shaped
cast-iron piece arranged in the chamber of the genera-
tor, in which the gases are developed, and is thus heated
to a high temperature. The mixture of air and steam
circulates in this super-heater before traveling to the
ash-pit.
The feeder of the Winterthur gas-generator (Fig.
122) is composed of a receptacle having the shape of a
tank or basin containing water and located below a
closed cylindrical box. In this box a piston moves,
which is provided at its lower end with a needle-valve.
FEEDERS
237
The upper portion of the box communicates with the
gas-suction pipe through a small tube. At each suction
stroke of the engine, according to the force of the suc-
tion, the needle-valve piston rises more or less and thus
allows a variable amount of water to pass.
FIG. 122. Winterthur feeders.
This apparatus and all those based on the same
principle presents the advantage of proportioning the
amount of water to the work of the engine; but in view
of its rather sensitive operation it must be kept in per-
fect repair and carefully watched. Obviously, should
the water contain impurities, the needle-valve will bind
238 GAS-ENGINES AND PRODUCERS
or the orifices will be obstructed, and thus the feeding
of the water will be interrupted. This \vill not only re-
sult in the production of a poorer gas, but will lead to
greater wear of the grates, which in this case are not
sufficiently cooled by the introduction of steam.
FIG. 123. Hille producer.
Air-Heaters. The preliminary heating of the air
appears to be of great utility for keeping up a good fire.
This heating is very easily accomplished, and is gen-
erally effected by utilizing a portion of the waste heat
of the gases, a procedure which also has the advantage
of cooling the gases before they pass through the wash-
ing apparatus.
DUST-COLLECTORS
2 39
The heating of the air for supporting combustion
takes place either before the addition of steam (Hille's
generator, Fig. 123), or after the mixture as in Wieden-
feld's apparatus (Fig. 95). In the first case, the air
passes through a sheet-iron shell concentric with the
basin of the generator, is there heated by the radiated
heat, and is conveyed to the ash-pit by a tube into which
leads the steam-supply pipe extended from the vapor-
izer. In the second type of heater, the mixture of air
and steam is super-heated during its passage through an
annular piece arranged in the ash-pit of the generator.
FIG. 124. Benz dust -collector.
Dust-Collectors. Dust-collectors are generally
placed between the generator and the scrubber or
washer. They may be formed of baffle-board arrange-
ments against which the gases laden with dust impinge,
causing the dust to be thrown down into a box provided
with a cleaning opening (Benz, Fig. 124, and Pintsch,
Fig. 118).
Some collectors are formed either by the vaporizer
itself, terminating at its base in a tube which dips into
water and forms a water-seal, as in the Wiedenfeld gen-
erator (Fig. 121), or by a water-chamber into which
the gas-supply tube slightly dips (Bollinckx, Fig. in).
240 GAS-ENGINES AND PRODUCERS
With this arrangement, the gas will bubble through the
water and will be partly freed of the dust suspended in
it. These water-chambers are generally fed by the
overflow from the spray of the scrubber. There is thus
produced a continuous circulation by which the dust,
in the form of slime, is carried toward the waste-pipe or
sewer.
Cooler, Washer, Scrubber. Some manufacturers
cool the gas in a tower with water circulation. Most
manufacturers, however, simply cool the gas in the
washer or scrubber. This apparatus comprises a cy-
lindrical body of sheet-iron or cast-iron formed of two
compartments separated by a wooden or iron grate or
perforated partition. The upper compartment up to
a certain level contains either coke, glass balls, stones,
pieces of wood, and the like. The top of the compart-
ment is provided with a water supply in the nature of
a sprinkler or spray nozzle. The lower compartment
of the scrubber serves to collect the wash-water which
has passed through the substance filling the tower. An
overflow in the shape of a siphon, provided with a water
seal, carries the water to the waste-pipe either directly
or after it has first passed through the dust collector.
The gas drawn in enters the washer in the lower com-
partment either above the water level (Deutz, Fig.
125; Winterthur, Fig. 126), or through an' elbow
which dips slightly into the water (Benz, Fig. 127;
Fichet and Heurtey producer, Fig. 128).
The gas passes through the grate or partition which
supports the material filling the tower, and travels
COOLER, WASHER, SCRUBBER 241
through the interstices in a direction opposite to that of
the water falling from the top. Under these conditions,
the gas is cooled, gives up the ammonia and the dust
FIG. 126. Winterthur scrubber.
FIG. 125. Otto Deutz scrubber.
which it may still contain in suspension, and is conveyed
to the engine either directly or after passing through
certain purifiers. Care should be taken to place the
242 GAS-ENGINES AND PRODUCERS
pieces of most regular shape along the walls, so that
the unevenness of their surfaces may not form upward
FIG. 127. Benz scrubber.
channels along the shell, through which channels the
gas could pass without meeting the wash-water.
The material most commonly employed in washers is
coke in pieces of from 2^ to 3^ inches in size. This
material is cheap and is very well suited for retaining
WASHERS
243
the impurities of the gas. The largest pieces of coke
should be placed at the bottom of the washer, and
smaller pieces should form at the top a layer from 6 to
FIG. 128. Fichet-Heurtey scrubber. FIG. 129. Scrubber-doors.
8 inches deep. In this manner the water is distributed
more evenly and the gas is more thoroughly washed.
Blast-furnace coke is best suited for this washing, as it
is more porous and less brittle than gas-works coke. It
244 GAS-ENGINES AND PRODUCERS
is advisable to put a baffle-board in front of the gas out-
let to reduce the carrying along of water in the con-
duits.
The tower of the washer should be provided with
three openings having air-tight closures, easily fastened
by screws (Fig. 129). One of the openings is located
in the lower compartment, slightly above the water
level, to allow the deposits to be removed and to per-
mit the cleaning of the orifice of the gas-supply tube,
which is particularly liable to be obstructed. The sec-
ond opening is placed above the grating which sup-
ports the filtering material. The third opening is pro-
vided on the top of the apparatus to permit the exam-
ination and cleaning of the water feed device and the
gas outlet without the necessity of taking the lid of the
washer apart, the joint of which is kept tight with diffi-
culty. The two openings last mentioned also serve for
introducing and removing the filtering material.
Purifying Apparatus. In some cases, w r here it is
necessary to have very clean gas or where coal is em-
ployed which is softer than anthracite coal, and which
therefore produces an appreciable amount of tar, sup-
plementary purifying means must be employed. The
apparatus for this purpose may, like the washers, be
based upon a physical action or upon a chemical action.
The physical action has for its purpose chiefly to re-
tain the pitch and the dust which may have passed
through the washer.
This is accomplished by means of sawdust or wood
shavings arranged in a thin layer and capable of filter-
PURIFIERS
245
ing the gas without opposing too great a resistance to
its passage. These materials are spread on one or more
shelves superposed to form successive compartments in
a box closed in an air-tight manner by an ordinary lid
or a water seal cover (Pintsch, Fig. 130; Fichet and
Heurtey, Fig. 131). It may be well to point out that
the presence of the water carried along will, in the end,
destroy the efficiency of the precipitated materials,
FIG. 130. Pintsch purifier.
because they swell up and cease to be permeable to
the gas. These materials must therefore be renewed
rather frequently. To obviate this drawback, vegetable
moss may be employed, which is much less affected by
moisture than most filters and keeps its spongy condi-
tion for a long time.
The chemical action has for its chief object to rid
the gas of the carbonic acid and the hydrogen sulphide
which certain fuels give off in appreciable amounts.
246 GAS-ENGINES AND PRODUCERS
The purifying material, in this case, is formed either
by a mixture of hydrate of lime and natural iron oxide,
or by the so-called Laming mass, which consists of iron
sulphide, slaked lime, and sawdust, which last serves
FIG. 131. Fichet-Heurtey purifier.
the purpose of rendering the material looser and more
permeable to the gas. The Laming mass as well as
other purifying materials will become exhausted in the
course of chemical reactions. It can be regenerated
merely by exposure to the air.
STORAGE OF GAS
247
Gas-Holders. The purifiers by themselves consti-
tute, to a certain extent, storage chambers for the gas
before it is supplied to the engine; but in plants for the
generation of gas without purifiers it is advisable to
provide a gas-holder on the suction conduit near the
engine.
In order to save floor space the gas-holder may be
FIG. 132. Pintsch regulating-bell.
placed in the basement. Preferably the capacity of
the holder should be at least from 3 to 4 times the vol-
ume of the engine-cylinder. The holder should also
be provided with a drain-cock and with a hand-hole
located at some accessible point, so that the slimes and
pitch which tend to accumulate in the holder can be
removed. In some cases the gas-holder is formed by a
248 GAS-ENGINES AND PRODUCERS
small regulating bell, the function of which is to in-
sure a uniform pressure. This bell is emptied during
the suction period and is filled during the three suc-
FIG. 133. Types of gas-driers.
ceeding periods of compression, explosion, and exhaust
(Pintsch, Fig. 132).
Drier. Sometimes, toward the end of a producer-
gas pipe, a drier is located for the purpose of keeping
back the water carried along, the drier being similar to
that employed in steam conduits. It will, of course, be
m
FIG. 134. Elbow with closure.
understood that such driers are useful only in plants
having no purifiers (Fig. 133). The employment of
the drier is advisable to prevent the entrance of moist
gas into the cylinder and the condensation of moisture
on the electric igniter.
Pipes. The pipes connecting the several parts of
PIPE CONNECTIONS 249
f *
a gas-producing plant should be disposed with partic-
ular care to insure tightness and cleanliness. It should
be borne in mind that the gas is under a pressure below
that of the atmosphere, and that the least leakage will
cause the entrance of air, which will impair the qual-
ity of the gas. The greatest care should therefore be
taken in fitting the joints. These joints are numerous,
because there are joints wherever tubes are connected
with each other and with the apparatus. Further-
more, all elbows should be provided with covers held
in place by a yoke and compression screw, this being
done for the purpose of providing for the introduction
of a brush or other implement to remove the dust and
pitch (Fig. 134).
For conduits of small diameter the elbows with cov-
ers may be replaced with T connections, or connections
provided with plugs.
Gas piping in the immediate neighborhood of the
cock for admitting gas to the motor should be provided
with a conduit of proper diameter leading to the open
air and serving to clean the apparatus and to fill them,
during the operation of the fan, with gas suitable for
combustion. This conduit should be provided with a
stop-cock. Test-cocks for the gas should be placed on
the piping immediately beyond the vaporizers, the
scrubber, and near the engine.
It will also be well to provide water-pressure gages
before and after the scrubber to enable the attendant
to ascertain the vacuum in the conduits and to adjust
the running of the apparatus.
GAS-ENGINES AND PRODUCERS
Purifying-Brush. As an additional precaution
against the carrying of tar to the engine, metallic
brushes are often employed, these brushes being spiral
in form and enclosed in a cast-iron box interposed in
the gas-supply pipe immediately after the engine. The
FIG. 135. Metal purifying-brush.
gas will be broken up into streams by the obstacles
formed by these brushes and will be freed of the sus-
pended tar (Fig. 135). These brushes should be care-
fully cleaned at regular intervals. The best way of
doing this is to drop them into kerosene or some other
suitable solvent.
SUCTION GAS-PRODUCERS 251
CONDITIONS OF PERFECT OPERATION
OF GAS-PRODUCERS
These conditions depend upon the workmanship or
upon the system of the plant, on the care with which
it has been erected, on the nature of the fuel, on
the condition of preservation of the apparatus, and
upon the manner in which the .producers have been
working.
Workmanship and System. The workmanship
itself, which term is meant to include the choice of
materials and the way they have been worked, presents
no difficulty. The producers which we have discussed
are very simple and offer absolutely no difficulties in
their mechanical execution. As regards the system,
however, especially with respect to the relative dimen-
sions of the elements, it does not seem so far that it is
possible to indicate any principle or rule capable of
a rigid general application. It must be taken into
account that the use of suction gas-generators has
become general only in the last three or four years;
the problem has therefore scarcely been adequately
solved. However, some hints may be given on this
subject.
Generator. In regard to the generator, it is pos-
sible to deduce from the best existing plants the dimen-
sions to be given to the generator relatively to those of
the engine to be supplied, upon the assumption that the
engine is single-acting and runs at a normal speed of
252 GAS-ENGINES AND PRODUCERS
from 1 60 to 230 revolutions per minute. The essential
portion of the generator which contributes to the pro-
duction of a proper gas is that which corresponds with
the combustion zone. To this portion a cross-section is
given varying in size between one-half and one-quarter
of the surface of the engine-piston, sometimes between
one-half and nine-tenths of this surface, according to
the nature and the size of the fuel that is used. With
small apparatus, however, ranging from 5 to 15 horse-
power, the size of the base cannot be reduced below a
certain limit, since otherwise the sinking of the fuel
will be prevented. This danger always exists in small
generators and renders their operation rather uncertain,
such uncertainty being also due to the influence of the
walls. It is to be noted that most modern generators are
rather too large than otherwise.
Many manufacturers of no wide experience have
been led to make their apparatus rather large so as to
insure a more plentiful production of gas. As a matter
of fact, the fire in such apparatus is liable to be extin-
guished when the combustion is not very active. If the
principles of the formation of gas in suction-generators
be kept in mind, it is evident that the gas developed is
the richer the " hotter " the operation of the apparatus.
Such operation also permits the decomposition of the
hydrogen and carbon monoxide.
The " hot " operation of a generator is accomplished
best with active combustion; and since this is a function
of the rapidity with which the air is fed, it obviously is
advantageous to reduce the area of the air-passage to a
VAPORIZER AND SCRUBBER
253
minimum as far as allowed by the amount of fuel to be
treated. As to the height of the fuel in use in the ap-
paratus, this varies as a rule between 4 and 5 times the
diameter at the base.
Vaporizer. The size of the vaporizer varies ma-
terially according to its type. No hard-and-fast rule
can therefore be adopted for determining its heating
surface; but this surface should in all cases be sufficient
to vaporize under atmospheric pressure from .66 to .83
pounds of water per pound of anthracite coal consumed
in the generator.
Scrubber. For the scrubbers, the following dimen-
sions may be deduced from constructions now used by
standard manufacturers.
The volume of a scrubber is generally from six to
eight times the anthracite capacity of the generator. A
height of from three to four times the diameter is con-
sidered sufficient in most cases. It should be under-
stood that in this height is included the water-pan
chamber located below the partition or grate, and the
upper chamber through which the gas escapes. The
height of these two chambers depends necessarily upon
the arrangement used for leading the gas to the lower
portion of the washer and for the distribution of wash-
water at the top.
Assembling the Plant. The author has insisted
strongly on the necessity of having all the apparatus
and pipe connections perfectly tight. In order to as-
certain if there is any leakage, the following procedure
may be adopted:
254 GAS-ENGINES AND PRODUCERS
When starting the fire by means of wood, straw, or
other fuel producing smoke, instead of allowing this
smoke to escape through the flue during the operation
of the fan, it may be caused to escape through the cock
which generally admits the gas to the motor, the cock
being opened for this purpose. The damper in the out-
let flue is closed. In this manner the smoke will fill all
the apparatus and connecting pipes under a certain
pressure and will escape through any cracks, the pres-
ence of w T hich will thus be revealed.
Another test, which is made during the ordinary op-
eration of the generator, consists in passing a lighted
candle along the joints ; if there is any leakage, this will
be shown by a deviation of the flame from a vertical
position.
Fuel. We have discussed the subject of fuel in a
preceding chapter (Chapter XIII) and have indicated
the conditions to be fulfilled by low grade or anthracite
coal best adapted for use in suction gas-generators. It
may here be added that the coal used in the generator
should be as dry as possible and in pieces of from
y 2 inch to i inch. Very small pieces, and particularly
coal dust, are injurious and should be removed by pre-
liminary screening as far as possible. Screened coal
is thrown in with an ordinary grate shovel.
How to Keep the Plant in Good Condition. In
regard to the generator, apart from the cleaning of the
grate and of the ash-pit, which may be done during
operation, it is necessary to empty the apparatus en-
tirely once a week, if possible, in order to break off the
MAINTENANCE OF PLANT
2 55
clinkers adhering to the retort. These clinkers destroy
the refractory lining, form rough projections interfer-
ing with the downward movement of the fuel, bring
about the formation of arches, and reduce the effective
area of the retort. At the time of this cleaning, tests
are also made as to the tightness of the doors of the
combustion-chamber, of the charging-boxes, etc.
The vaporizer should be cleaned every week or every
other week, according to the more or less bituminous
character of the fuel and the greater or smaller content
of lime in the water used. Lime deposits may be
eliminated, or the salts may be precipitated in the form
of non-adhering slimes, by introducing regularly a
small amount of caustic postash or soda into the feed-
water. If the deposits or incrustations are very tena-
cious, the use of a dilute solution of hydrochloric acid
may be resorted to. Tar which may adhere to the
conduits, pipes or gas passages, is best removed while
the apparatus is still hot, or a solvent may be employed,
such as kerosene, turpentine, etc. The connections be-
tween the vaporizer and the scrubber are particularly
liable to become obstructed by the accumulation of tar
or dust carried along by the gas.
It is advisable to examine the several parts of the
plant once or twice a week by opening the covers or the
cleaning-plugs.
The lower compartment of the washer keeps back
the greater part of the dust which has not been retained
in collectors or boxes provided especially for this pur-
pose. The dust takes the form of slime, and, in some
256 GAS-ENGINES AND PRODUCERS
arrangements of apparatus, tends to clog up the over-
flow pipe, thus arresting the passage of *gas and causing
the engine to stop. This portion of the washer should
be thoroughly cleaned once or twice a month.
If very hard blast-furnace coke is used in the washer,
it may be kept in use for over a year without requiring
removal. In order to free the purifying materials from
dust and lime sediments carried along by the wash-
water, it is well to let the wash-water flow as abundantly
as possible for about a half-hour at least once a month.
At the time of renewing the purifying material the
precautions indicated in the section dealing with these
matters should be observed, and care should be taken
to have shelves or gratings on which the material is
supported in layers not too thick, so as to avoid any
resistance to the passage of the gas.
In a general way it is advisable to test the drain-
cocks on the several apparatus daily, and to keep them
in perfect condition. If, when open, one of these cocks
does not discharge any gas, water, or steam, a wire
should be introduced into the bore to make sure it is
not clogged up.
Care of the Apparatus. Each producer-gas plant
will require special instructions for running it, accord-
ing to the system, the construction, and the size of the
plant. Such instructions are generally furnished by
the manufacturer. However, there are some general
rules which are common to the majority of suction gas-
producers, and these will here be enumerated.
Starting the Fire for the Gas Generator. This
CARE OF THE APPARATUS 257
operation calls for the presence of the engineer of the
plant and an assistant. The proper procedure is as fol-
lows :
First: Open the doors of the furnace and of the ash-
pit. Then open the outlet flue and make sure that the
grate of the generator is clear of ashes and clinkers. It
should also be seen to that the parts of the charging-box
work well and that the joints are tight.
Second: Ascertain whether there is the proper
amount of water in the vaporizer, in the scrubber, etc.,
and that the feed works properly.
Third: Through the door of the combustion-cham-
ber introduce straw, wood .shavings, cotton waste, etc. ;
light them and fill the generator with dry wood up to
one-quarter or one-half of its height; then add a few
pailfuls of coal.
Fourth: Close the doors of the ash-pit and of the
combustion-chamber and start the draft by means of the
fan. As soon as the draft is started, it must be kept up
without interruption until the engine begins to run,
which may be ten or twenty minutes after lighting
the fire.
Fifth: After the draft has been continued for a few
minutes, the coal becomes sufficiently incandescent to
start the production of gas, which may be ascertained
by trying to light the gas at the, test-cock near the gen-
erator. Then the opening in the outlet flue is half
closed for the purpose of producing pressure in the
apparatus.
Sixth : Open the outlet flue adjacent to the engine for
258 GAS-ENGINES AND PRODUCERS
the purpose of purging the apparatus and the conduits
of the air which they contain until the gas may be
lighted at the test-cock placed near the motor.
Seventh: Adjust the normal outflow of wash-water
for the scrubber.
Eighth: As soon as the gas burns continuously at the
test-cock with an orange-colored flame the engine may
be started.
The gas at first burns with a blue flame; this color
indicates that it contains a certain amount of air. The
opening of the test-cock should be so regulated as to
reduce the outlet pressure of the gas sufficiently to pre-
vent the flame from going out. During the production
of the draft, as well as during the ordinary running of
the plant, the filling of the apparatus with fuel should
be done with care to prevent explosions of gas due to the
entrance of air. Particular care should be taken never
to open at the same time the lid of the charging-box and
the device, be it a cock, valve, or damper, which con-
trols the connection of the charging-box with the gen-
erator. All the operations which have been mentioned
above should be carried out as quickly as possible.
STARTING THE ENGINE
The manner of starting the engine depends on the
type of the engine and on the starting device with
which it is provided, as we have already explained in
connection with engines working with gas from city
mains.
STARTING THE ENGINE
259
It is, however, important for the production of a
good explosive mixture to regulate the amount of air
supplied to the engine according to the quality of the
gas employed. It is advisable to continue the operation
of the fan until several explosions have taken place in
the cylinder and the engine has acquired a certain
speed so as to be able to draw in the normal amount
of gas.
Naturally the gas-outlet tube near the admission-
cock should be closed after starting the engine, as
well as the opening in the outlet flue of the generator.
When the motor is running properly, the amount of
water fed to the vaporizer and overflowing to the ash-
pit is properly adjusted. The generator is then filled
up to the level indicated by the manufacturer.
Care of the Generator during Operation. As
soon as the apparatus is running under normal con-
ditions, it presents the advantage of requiring only very
slight supervision and very little manual tending. The
supervision consists:
First: In regulating and keeping up a proper feed
of water to the vaporizer.
Second: In seeing to it that in apparatus provided
with an overflow leading to the ash-pit, the water
should flow constantly but without exceeding the
proper amount.
Third: In keeping down temperature in the scrub-
ber by properly regulating the feed of the wash-water.
This apparatus may be slightly warm at its lower part,
but must be quite cold at the top.
2 6o GAS-ENGINES AND PRODUCERS
The manual tending to be done is limited to the reg-
ular filling up of the generator with fuel and to the
removal of ashes and clinkers. The charging is effected
at regular intervals, which, according to the various
types of anthracite-generators, vary from one to six
hours. Charging the apparatus at short intervals en-
tails unnecessary labor, while charging at too long
intervals will often interfere with the uniform produc-
tion of the gas.
It will be obvious that the amount of fuel introduced
will be the larger, the greater the intervals between two
fillings. This fuel is cold and contains between its
particles a certain amount of air; furthermore, the layer
of coal which covers the incandescent zone has become
relatively thin. The excess of air impoverishes the gas,
and the fresh fuel lowers the temperature of the mass
undergoing combustion, so that again the gas in process
of formation is weakened. Experience seems to show
that as a rule it is best to fill up the generator at inter-
vals of from two to three hours, according to the work
done by the engine. It should be noted that the level
of the fuel in the generator should not sink below the
bottom of the feed-hopper.
The author wishes again to emphasize that in order
to prevent the harmful entrance of air, the charging
operations should be carried out as quickly as possible;
and for this reason the fuel should be introduced not by
means of the shovel, but by means of a pail, scuttle, or
other appropriate receptacle.
Care should be taken to fill the charging box to its
STOPPAGES AND CLEANI
i
upper edge and to adjust its cover accurately before
operating the device which closes the feed-hopper
(valve, cock).
The removal of the ashes and clinkers should be ac-
complished as infrequently as possible, since opening
the doors of the ash-pit and of the combustion-chamber
necessarily causes an inward suction of cold air which
is harmful.
As a rule with generators employing anthracite coal,
it is sufficient to empty the ash-pit twice daily; this
should be preferably done during stoppages. How-
ever, the cleaning of the grate by means of a poker
passed between the grate-bars or over them in order
to bring about the falling of the ashes, should be at 1
tended to every two to four hours, according to the type
of the generator and the nature of the fuel. In order
that this cleaning may be done without opening the
doors, the latter should be provided with apertures hav-
ing closing devices.
This cleaning has for its chief object to allow the free
passage of the air for supporting combustion and to
keep the incandescent zone in the apparatus at the
proper height. The accumulation of ashes and clinkers
at the bottom of the retort will shift this zone upward
and impair the quality of gas.
Stoppages and Cleaning. After closing the gas-
' inlet to the engine, the damper in the gas-outlet flue
of the generator should be opened and the cocks con-
trolling the feed of water to the scrubber and to the
vaporizer should be closed.
262 GAS-ENGINES AND PRODUCERS
If it is desired to keep up the fire of the generator
during the stoppage so as to be able to start again
quickly, the ash-pit door should be opened so as to pro-
duce a natural draft which will maintain combus-
tion. While the door is open, the clinkers which have
accumulated above the grate may be removed, as they
are much more easily taken off the grate when they
are hot.
At least once a week the fire in the generator should
be put out and the generator completely cleaned that
is, when ordinary fuel is employed. For this purpose,
as soon as the apparatus is stopped, a portion of the in-
candescent fuel is withdrawn through the doors of the
combustion-chamber, and the retort is allowed to cool
before it is emptied entirely. Too sudden a cooling of
the retort may injure its refractory lining. In order
to prevent explosions caused by the entrance of air, the
feed-hopper should remain hermetically closed during
the removal of the incandescent fuel through the doors
of the combustion-chamber.
If the apparatus is placed in a room poorly venti-
lated, the cleaning should be attended to by two men,
so that one may assist the other in case he is overcome
by the gas. In all cases there should be a strict prohibi-
tion against the use of any light having an exposed
flame liable to set on fire the explosive mixtures which
may be formed.
When the generator, after cooling, is completely
open, the charging-box is taken apart, and, if necessary,
the feed-hopper also; the grates are taken out, if neces-
STOPPAGES AND CLEANING 263
sary; and, by means of a poker inserted from above, the
clinkers and slag adhering to the retort are broken
off.
In the foregoing paragraphs the author has indicated
how the several apparatus, such as the vaporizer, the
washer, the conduits, etc., should be attended to and
maintained in good working order.
CHAPTER XIV
OIL AND VOLATILE HYDROCARBON ENGINES
ALTHOUGH this book is devoted primarily to a dis-
cussion of street-gas and producer-gas engines em-
ployed in various industries, a few words on oil and
volatile hydrocarbon engines may not be out of place.
Oil-engines are those which use ordinary petroleum
as a fuel or illuminating oil of yellowish color, having
a specific gravity varying from 0.800 to o.-Sao at a tem-
perature of 15 degrees C. (490 degrees F.), and boiling
between 140 and 145 degrees C. (284 to 297 degrees
F.). Volatile hydrocarbon engines are those which
employ light oils obtained by distilling petroleum.
These oils are colorless, have a specific gravity that
varies from 0.680 to 0.720, and boil between 80 degrees
and 115 degrees C. (176 to 257 degrees F.). Among
these " essences," as they are called in Europe, may be
mentioned benzine and alcohol.
In general appearance, and the way in which they
are controlled, oil-engines differ but little from gas-
engines. Their usual speed, however, is 20 to 30 per
cent, greater than that of gas-engines. Except in some
engines of the Diesel and Banki types, the compression
does not exceed 43 to 71 pounds per square inch. In
volatile hydrocarbon engines, on the other hand, the
speed is very high, often running from 500 to 2,000
264
OIL-ENGINES 265
revolutions per minute, while the speed of gas or oil
engines rarely exceeds 250 or 300 revolutions per
minute.
Oil - Engines. Oil-engines are employed chiefly in
Russia and in America. Because of the high price of
oil in other countries they are to be found only in small
installations in country regions and are used mainly
for driving locomobiles and launches. The improve-
ments which have been made of late years in the con-
struction of gas-engines supplied by suction gas-pro-
ducers for small as well as for large powers, have hin-
dered the general introduction of oil-engines.
The characteristic feature in the design of many of
the oil-engines of the four-cycle type now in use (to
which type we shall confine this discussion) is to be
found in the controlling mechanism employed. The
underlying principle of this mechanism lies not in acting
upon the admission-valve, but in causing the governor
to operate the exhaust-valve in such a manner that it
is held open whenever the engine tends to exceed its
normal speed. Some engines, however, are built on the
principle of the gas-engine, with an admission-valve so
controlled by the governor that it is open during nor-
mal operation and closed whenever the speed becomes
excessive.
The necessity of producing a mixture of air and oil
capable of being ignited in the engine-cylinder has
led to the invention of various contrivances, which
cannot be used if illuminating-gas or producer-gas be
employed. These contrivances are the atomizer, the
266 GAS-ENGINES AND PRODUCERS
carbureter, the oil-pump, the air-pump, the oil-tank,
and the oil-lamp. In some oil-engines all of the ele-
ments may be found, but for the purpose of simplifying
the construction and of avoiding unnecessary complica-
tions, manufacturers devised arrangements which ren-
dered it possible to discard some of them, particularly
those of delicate construction and operation. It is
not the intention of the author to enter into a detailed
description of these various devices, since the limita-
tions of this book would be considerably surpassed. The
reader is referred to books on the oil-engine, published
in the United States, England, and France.*
Most of the observations which have been made on
the construction and installation of gas-engines, as well
as the precautions which have been advised in the con-
duct of an engine, apply with equal force to oil-engines.
It will therefore be unnecessary to recur to this phase
of the subject so far as oil-engines are concerned. One
point only should be insisted upon the necessity of
very frequently cleaning the valves and moving parts
of the engine.
Illuminating-oil when burnt produces sooty deposits,
particularly if combustion be incomplete, which de-
posits foul the various parts and cause premature igni-
tions and faulty operation.
* Hiscox, Gas and Oil Engines, Norman W. Henley Pub. Co., New
York. Parsell and Weed, Gas and Oil Engines, 1900, Norman W.
Henley Pub. Co., New York. Goldingham, 1900, Spon & Chamberlain,
London. Dugald Clerk, 1897, Longmans, London. Grover, 1902, Hey-
wood, Manchester. Aime Witz, 1904, Barnard, Paris. H. Giildner, 1903,
Springer, Berlin.
HYDROCARBON ENGINES 267
t .
The use of oil in atomizers, carbureters, and lamps
is accompanied with the employment of pipes and open-
ings so small in cross-section that the slightest negligence
is attended with the formation of partial obstructions
that inevitably affect the operation of the engine.
Volatile Hydrocarbon Engines. Only those en-
gines will here be treated which have become of im-
portance in the development of the automobile.
Some designers have attempted to employ the vola-
tile hydrocarbon engine for industrial and agricultural
purposes, and have devised electro-generator groups,
hydraulic groups, and so-called " industrial combina-
tions " in which belt and pulley transmission is em-
ployed. These applications in particular will here be
rapidly reviewed.
The high speed at which engines of this class are
driven renders it possible to operate a centrifugal pump
directly and to mount both the engine and machine
which it actuates on the same base. The hydrocarbon
engine has the merit of being very light and of taking
up but little room. Its cost is considerably less than
that of an oil or producer-gas engine of corresponding
power. On the other hand, its maintenance is much
more expensive, and the hydrocarbons upon which it
depends for fuel anything but cheap. Furthermore,
the engines wear away rapidly, on account of their high
speed. For this reason it is advisable to base calcula-
tions on a life of three to four years, while oil and gas
engines may generally be considered to be still of ser-
vice at the end of thirteen years. On the following
268 GAS-ENGINES AND PRODUCERS
page a comparison of costs for installation and main-
tenance is drawn between the oil and hydrocarbon
engine on the basis of ten horse-power.
Comparative Costs. A 10 horse-power oil-engine,
in the matter of first cost of installation, is about 35
per cent, more expensive than a volatile hydrocarbon
engine of equal power. On the other hand, the operat-
ing expenses of the oil-engine are less by 25 per cent,
than they are for the volatile hydrocarbon engine.
The engines which are here discussed usually have
their cylinders vertically arranged, as in steam-engines
of the overhead cylinder type. The crank-shaft and
the connecting-rods are enclosed in a hermetically
sealed box filled with oil, so that the movement of the
parts themselves ensures the liberal lubrication of the
piston. The suction-valve is generally free, although
latterly designers have shown a tendency to connect
it with the cam-shaft, with the result that it has become
possible to reduce the speed appreciably without stop-
ping the engine. The carbureter is operated by the
suction of the engine. If the fuel employed is alcohol,
it must be heated.
Tests of High-speed Engines. High-speed engines
present various difficulties which must be contended
with in controlling their operation. Their high speed
renders it impossible to take indicator records as in the
case of most industrial engines. Indicator cards, more-
over, at best give but very crude data, which relate to
each explosion cycle only, and which are therefore in-
adequate in determining the exact conditions of an en-
EXPLOSION RECORDS 269
9
gine's operation. Oil, benzine, and other so-called car-
bureted-air engines are particularly difficult to control
because of many phenomena which cannot be recorded.
In order to test the operation of high-speed engines,
two different types of instruments are at present em-
ployed: the manograph and the continuous explosion
recorder.
The Manograph. The manograph, which is the
invention of Hospitalier, is an optical instrument in
which a series of closed diagrams are superimposed
upon a polished mirror similar in form to Watt
diagrams. Because the images persist in affecting the
retina of the eye an absolutely continuous, but tem-
porary, gleam is seen. Still, it is possible to obtain a
photograph or a tracing of these diagrams.
The Continuous Explosion Recorder for High-
speed Engines. The author has devised an explo-
sion and pressure recorder, which is mounted upon the
explosion chamber to be tested and which communi-
cates with the chamber through the medium of a
cock r (Fig. 136) . The instrument is somewhat similar
in form to the ordinary indicator. Its record, however,
is made on a paper tape which is continuously un-
wound. The cylinder c is provided with a piston />,
about the stem of which a spring s is coiled. A clock
train contained in the chamber b unwinds the strip of
paper from the roll p' and draws it over the drum />',
where the pencil t leaves its mark. The tape is then
rewound on the spindle p'". A small stylus or pencil f
traces " the atmospheric line " on the paper as it passes
270 GAS-ENGINES AND PRODUCERS
over the drum p". In order to obviate the binding of
the piston p when subjected to the high temperature of
FIG. 136. R. Mathot's continuous explosion recorder.
the explosions, the cylinder c is provided with a casing
e in which wat^r is circulated by means of a small rub-
ber tube which fits over the nipple e '. This recorder
THE EXPLOSION RECORDER 271
9
analyzes with absolute precision the work of all en-
gines, whatever may be their speed. It gives a con-
tinuous graphic record from which the number of ex-
plosions, together with the initial pressure of each, can
be determined, and the order of their succession. Con-
sequently the regularity or irregularity of the variations
can be observed and traced to the secondary influences
producing them, such as the section of the inlet and out-
let valves and the sensitiveness of the governor. It
renders it possible to estimate the resistance to suction
and the back pressure due to expelling the burnt gases,
the chief causes of loss in efficiency in high-speed en-
gines. Furthermore, the influence of compression is
markedly shown from the diagram obtained.
The recorder is mounted on the engine; its piston is
driven back by each of the explosions to a height cor-
responding with their force; and the stylus or pencil
controlled by the lever t records them side by side on
the moving strip of paper. The speed with which this
strip is unwound conforms with the number of revolu-
tions of the engine to be tested, so that the records
of the explosions are placed side by side clearly and
legibly. Their succession indicates not only the num-
ber of explosions and of revolutions which occur in
a given time, but also their regularity, the number
of misfires. The atmospheric pressure of the explo-
sions is measured by a scale connected with the re-
corder-spring. By employing a very weak spring
which flexes at the bottom simply by the effect of
the compression in the engine-cylinder, it is possible
272 GAS-ENGINES AND PRODUCERS
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AMOUNT OF COMPRESSION
273
to ascertain the'amount of the resistance to suction and
to the exhaust. It is simply sufficient to compare the
explosion record with the atmospheric line, traced by
the stylus /. By means of this apparatus, and of the
records which it furnishes, it is possible analytically to
regulate the work of an engine, to ascertain the propor-
tion of air, gas, or hydrocarbon, which produces the
most powerful explosion, to regulate the compression,
the speed, the time of ignition, the temperature, and the
like (Figs. 137, 138 and 139).
In order to explain the manner of using this recorder
several specimen diagrams are here given.
I. Determination of the Amount of Compression.
A spring of average power is employed, the total flexion
of which corresponds almost with the maximum com-
pression so as to obtain a curve of considerable ampli-
tude. The engine is first revolved without producing
explosions, driving it from the dynamo usually em-
ployed in shops, at the different speeds to be studied.
The compression of the mixture varies in inverse ratio
to the number of revolutions of the shaft, owing to the
resistances which are set up in the pipes and the valves
and which increase with the speed. The accompany-
ing cut (Fig. 140) shows two distinct records taken in
two different cases, namely:
A. Speed of engine, 950 revolutions per minute;
amount of compression, 68.9 pounds per square inch.
B. Speed of engine, 1,500 revolutions per minute;
amount of compression, 61 pounds per square inch, or
1 1.5 per cent. less.
274 GAS-ENGINES AND PRODUCERS
II. Determination of the Resistance to Suction and
Exhaust. Influence of the tension of the spring of the
suction valve and of the section of the pipe. Effect of
14 r
ATMOSPHERIC L
LINE |
1
FIG. 140.
the section of the exhaust-valve and of the length and
shape of the exhaust-pipe:
A very light spring is utilized, the travel of which is
limited by a stop so as to obtain on a comparatively
large scale the depressions and resistance respectively
represented by the position of the corresponding curve,
above or below the atmospheric line (Fig. 141).
170.6 Ibs.per sq.in.
~
ATMOSPHERIC LINE f- \^
o
FIG. 141.
C. Tension of the suction-valve: 2.9 pounds. Re-
sistance to suction: \ of an atmosphere (2.7 pounds).
D. Tension of the suction-valve: 2.17 pounds. Re-
sistance to suction: -f- of an atmosphere (5.4 pounds).
E.--A chest is used for the exhaust. Resistance to
exhaust: f of an atmosphere (^.4 pounds).
F. The exhausted gases are discharged into the air,
EXPLOSION RECORDS
275
the pipe and the chest being discarded. Resistance to
the exhaust is zero (Fig. 142).
The depression graphically recorded is partly due
to the inertia of the spring of the explosion-recorder.
28,44 !bs.per sq.in.
14,22 Ibs.per sq.in.
ATMOSPHERIC I
FIG. 142.
which spring expands suddenly when the exhaust is
opened.
III. Comparison of the Average Force of the Ex-
plosions by Means of Ordinates. A powerful spring is
employed. The paper band or tape of the recorder
is moved with a small velocity of translation so as to
approximate as closely as possible the corresponding
ordinates representing the explosions (Fig. 143).
498 Ibs.per sq,in.
427 it
284
142 --
ATMOSPHERIC CINE
The Norman W. Senlty Pub. Co,\
FIG. 143.
G. Pure alcohol. Explosive force, 369.72 to 426.6
pounds per square inch.
H. Carbureted alcohol. Explosive force, 397.6 to
510.8 pounds per square inch.
I. Volatile hydrocarbon. Explosive force, 483.48
to 531.92 pounds per square inch.
276 GAS-ENGINES AND PRODUCERS
IV. Analysis of a Cycle by Means of Open Diagrams
Representing the Four Periods. A powerful spring is
employed, and the paper is moved with its maximum
speed of translation. The four phases of the cycle are
easily distinguished as they succeed one another graph-
ically from right to left in other words, in a direction
opposite to that in which the paper is unwound. A
diagram is made which reproduces exactly the values
of the corresponding pressures at different points in the
travel of the piston (Fig. 144). The periods of the
I
I
ATMOSPHERIC LINE L -
Th* Xorman W. Henley Pub. Co.
FIG. 144.
cycle are reproduced as faithfully a$ if the ordinary in-
dicator which gives a closed curved diagram had been
employed. There is no difficulty in reading the record,
since the paper is not in any way connected with the
engine-piston. Some attempts have been made to secure
open diagrams in which the motion of translation given
to the paper is controlled by the engine itself; but these
apparatus as well as the ordinary indicators cannot be
used when the speed of the engine exceeds 400 to 500
revolutions per minute.
J. Speed, 1,200 revolutions; carbureted alcohol;
average force of the explosions, 426.6 pounds per
square inch. Average compression, 92.43 pounds per
square inch. Pressure at the end of the expansion,
21.33 pounds per square inch.
ANALYSIS OF RECORDS
277
V. Analysis of the Inertia of the Recorder. Selection
of the Spring to be Employed. Given the rapidity
with which the explosions succeed one another in auto-
mobile engines, it is readily understood that the inertia
of the moving parts of the recorder will be graphically
reproduced (Fig. 144). The effect of this inertia is a
function of the weight of the moving parts and of the
extent of their travel.
The moving masses are represented by the piston and
its rod, the spring and the levers of the parallelogram
stylus. The effects due to inertia have been consider-
ably lessened by reducing the weight of the various
parts to a minimum. A hollowed piston, a hollowed
rod and short and light levers have been adopted. The
traditional pencil has been displaced by a silver point
which traces its mark upon a metallically coated paper.
For the heavy springs with their long travel, light but
powerful springs with small amplitudes have been sub-
stituted. Since the perfect lubrication of the recorder-
cylinder is of great importance, a simple oiling device
certain in its action has been adopted. The recess of the
piston forms a cup that can be filled with oil whenever
the spring is changed.
At each explosion the violent return of the piston
splashes oil against the cylinder walls and thus insures
perfect lubrication. It should be observed that if the
directions given are not followed, particularly in the
choice of a spring suitable for each experiment, inertia
effects will be produced. These can easily be detected
on the record and cannot be confused with the curves
278 GAS-ENGINES AND PRODUCERS
which interpret the phenomena occurring in the cyl-
inder of the engine. At a height equal to the end
of the piston's stroke, the cylinder of the recorder is
provided with a water-jacket which keeps the tempera-
ture down to a proper point and prevents the binding of
the piston.
The explosion-chamber of automobile engines being
rather small in volume, should not be sensibly increased
in order that the record obtained may conform as nearly
as possible with actual working conditions on the road.
In order to attain this end the cylinder of the recorder
is so disposed that the piston travels to the height of the
connecting-cock. As a result of this arrangement the
field of action of the gases is reduced to a minimum.
Since these gases have no winding path to follow, they
are subjected neither to loss of quantity nor to cold.
CHAPTER XV
THE SELECTION OF AN ENGINE
THE conditions which must be fulfilled both by en-
gines and gas-producers in order that they may in-
dustrially operate with regularity and economy have
been dwelt upon at some length. Unfortunately it often
happens that engines are not installed as they should be,
with the result that they run badly and that the reputa-
tion of gas-engines suffers unjustly. The use of suction
gas-producers in particular caused considerable trouble
at first owing to inexperience, so that even now many
hesitate to adopt them despite their great economical
advantages. The reason assigned for this hesitation is
the supposed danger attending their operation.
The factory proprietor who intends to install a gas-
engine in his plant is not usually able to appreciate the
intrinsic value of one engine when compared with an-
other, or to determine whether the plans -for an installa-
tion conform with the best practice. The innumerable
types of engines offered to him by manufacturers and
their agents, each of whom claims to have a better en-
gine than his rivals, plunges the purchaser into hesita-
tion and doubt. Not knowing which engine to select, he
usually buys the cheapest. Very often he learns, as time
goes by, that his installation is far from being perfect.
279
280 GAS-ENGINES AND PRODUCERS
Finally he begins to believe that he ought to consult an
expert. The author's personal experience has con-
vinced him that eight times out of ten the factory owner
who has picked out an engine for himself has not ob-
tained an installation which meets the requirements
which the manufacturers of gas-engines should fulfil.
Many of these requirements could be complied with
were it not for the ,fact that the manufacturer has
dropped certain details which appeared superfluous,
but which were in reality very important in obtaining
perfect operation. The author therefore suggests that
the services of a competent expert be retained by those
who intend to install a gas-engine in their plants.
The Duty of a Consulting Engineer. An expert
fills the same office as an architect, and impartially
selects the engine best suited to his client's peculiar
needs. His examination of the engines offered to him
will proceed somewhat according to the following pro-
gramme :
1. He will first study the installation from the
mechanical point of view, and also the local conditions
under which that installation is to operate, in order that
he may not order an engine too large or too small, or
a type incompatible with the foundations at his dis-
posal, or unable to fulfil all the requirements of his
client.
2. He will examine the precautions which have been
taken to avoid or reduce to a minimum certain incon-
veniences which attend the operation of explosion-
engines.
SPECIFICATIONS 281
;-0l'
3. He will draw up specifications, with the terms
of which gas-engine makers must comply, so that he can
compare on the basis of these specifications the merits
of the engines submitted to him.
4. He will prepare an estimate of cost and also a
contract which is not couched in terms altogether in the
gas-engine maker's favor, and which gives the pur-
chaser important warranties.
5. He will supervise the technical installation of the
engine or plant.
6. He will make tests after the engine is installed and
see to it that the maker has fulfilled his warranties.
Specifications. Since engines and gas-producers are
constructed for commercial ends, it naturally follows
that their manufacturers seek to make the utmost possi-
ble profit in selling their installations. Prices charged
will necessarily vary with the quality of material em-
ployed, the care taken in constructing the engine and
generator, the number of apparatus of the same type
which are manufactured, the arrangement of the parts
and that of the installations. Since there is considerable
rivalry among gas-engine builders, selling prices are
often cut down so far that little or no profit is left. It
is very difficult indeed impossible to convince a pur-
chaser that it is to his interest to pay a fair price in order
to obtain a good installation, especially when other
manufacturers are offering the same installation at a less
price with the same warranties. As a result of this state
of affairs, engine builders, in order that they may not
lose an order, are willing to reduce their prices, hoping
282 GAS-ENGINES AND PRODUCERS
to make up in the quality of the workmanship and the
material what they would otherwise lose. Often they
will deliver an engine too small in size but operating at
a higher speed than that ordered; or they will select an
old type, or carry out certain details with no great care.
, This, to be sure, is not always the case; for there are
a few builders of engines who place their reputation
above everything else and who would rather lose an
order than execute it badly. Others, unfortunately,
prefer to have the order at all costs.
By retaining a consulting engineer, all these diffi-
culties are overcome. In the first place, the engineer
draws up a scale of prices and specifications which must
be complied with in their entirety as well as in all de-
tails. Rival engine builders are thus compelled to
make their estimates according to the same standard,
so that one engine can readily be compared with an-
other with the utmost fairness. In these specifications,
penalties will be provided for by the engineer which
will be levied if the warranties of the maker are not ful-
filled. Otherwise the warranties are worth nothing.
The first consequence of engaging a consulting en-
gineer is to render the matter of cost a secondary one.
A factory owner who employs a consulting engineer
and pays him for his services, is impelled chiefly by the
desire to obtain a good installation which will perform
what he expects of it. For that reason necessary sacri-
fices will be made to comply with the client's wishes.
If the purchaser considers the question of cost most
important to him, he need not engage an expert to
NECESSITY OF AN EXPERT 283
supervise the installation of his engines. He has simply
to pick out the cheapest engine. Unfortunately, how-
ever, the money which he will save by such a procedure
will be more than compensated for by the trouble which
he will later experience when his motor stops or when
it breaks down, because it has been cheaply built in the
first place.
The advice of a consulting engineer is therefore of
importance to the purchaser, because an engine. will be
installed which will in every way meet his require-
ments. The gas-engine builder will also prefer to deal
with an engineer, because the engineer can appreciate
at their true worth good material and good workman-
ship and place a fair valuation upon them. The specifi-
cations of a gas-engine and gas-producer expert are ac-
cepted by most engine builders, because an expert will
not introduce conditions which cannot be fulfilled.
Some manufacturers refuse to consider the conditions
imposed by specifications seriously, or else they fix dif-
ferent prices and make tenders on the basis of these
with or without specifications. In either case the pur-
chaser may be sure that he is not receiving what he has
a right to exact.
Testing the Plant. When the engine has been
selected the consulting engineer supervises its installa-
tion, and, after this is completed, carries out tests in
order to determine whether or not the guaranteed
power and consumption are attained. The methods
employed in testing a gas-engine are both complex and
delicate. The quality of the gas, the proportions of the
284 GAS-ENGINES AND PRODUCERS
elements forming the mixture, the time and the method
of ignition, the temperature of the cylinder-walls, the
temperature and the pressure of the gas drawn into the
cylinder, all these are factors which have a decided
bearing upon the results of a test. If these factors be
not carefully considered the conclusions to be drawn
from the test may be absolutely wrong.
Indicators of any type should not be indiscriminately
employed; only those specially designed for gas-engine
purposes should be used. Indicator cards are in them-
selves inadequate, and should be supplemented by the
records of explosion-recorders.
The calorific value of the gas should be measured
either by the Witz apparatus or by means of any other
calorimeter.
In interpreting the diagrams and records some dif-
ficulty will be encountered. Sometimes it happens that
a particular form of curve is attributed to a cause en-
tirely different from the real one. It happens not infre-
quently that engineers, whose experience is confined to
engines of one make and who have not had the oppor-
tunity to make sufficient comparisons, draw such erro-
neous conclusions from cards.
To recapitulate what has already been said, the test-
ing of gas-engines requires considerable experience and
cannot be lightly undertaken. Special instruments of
precision are necessary. The author has very often been
called upon to contradict the results obtained by ex-
perts whose tests have consisted simply in ascertaining
the engine power either by means of a Prony brake, or
TESTING THE ENGINE 285
9
by means of a brake-strap on the fly-wheel. The brake
gives but crude results at best; it is a means of control,
and not an instrument of scientific investigation.
Something more than the mere power produced by
an engine should be ascertained. The tests made should
throw some light upon the reasons why that power can-
not be exceeded, and show that the necessary changes
can be made to cause the engine to operate more eco-
nomically and to yield energy of an amount which its
owner has a right to expect. The indicator and the
recorder are testing instruments which clearly indicate
discrepancies in operation and the means by which they
may be corrected. The tests made should determine
whether the power developed is not obtained largely by
means of controlling devices which cause premature
wearing away of the engine parts.
It is not the intention of the author to describe indica-
tors of the well-known Watt type. It is simply his pur-
pose to call attention to the explosion-recorder which
he has devised to supplement the data obtained by
means of the indicator.
Explosion-Recorder for Industrial Engines. The
explosion-recorder illustrated in Fig. 145 can be
adapted to any ordinary indicator. It is composed of
a supporting bracket B upon which a drum T is
mounted. This drum is rotated by a clock-train, the
speed of which is controlled by means of a special com-
pensating governor. The entire system is pivotally
mounted upon the supporting screw O, so that the drum
T f about which a band of paper is wound, may be
286 GAS-ENGINES AND PRODUCERS
FIG. 145. Mathot explosion-recorder.
THE EXPLOSION-RECORDER 287
swung against a stylus C, which records upon* the paper
the number and power of the explosions. These explo-
sions are measured according to scale by a spring con-
nected with an indicator. The records obtained dis-
close for any given cycle the amount of compression as
w r ell as the force of the explosion, and render it possible
to study the phenomena of expansion, exhaust, and suc-
tion. They are, however, inadequate in showing ex-
actly how an engine runs in general. Indeed, in most
gas-engines, as well as oil and volatile hydrocarbon en-
gines, each explosion differs from that which follows in
character and in power; and it is absolutely essential to
provide some means of avoiding these variations. The
explosion-recorder gives a graphic record from which
the number of explosions can be read, and also the ini-
tial pressure of each explosion, the number of corre-
sponding revolutions, the order in which the explosions
succeed one another, and consequently the regularity of
certain phenomena caused by secondary influences, such
as the section of the distributing members, the sensitive-
ness of the governor, and the like.
The explosion-records can be taken simultaneously
with ordinary diagrams. In order to attain this end,
the recorder is allowed to swing around the pivot O, so
that the drum carrying the paper band is brought into
engagement, or swung out of engagement with the
stylus, as it is influenced by each explosion, thereby
leaving its record on the paper. The, ordinary diagram
may be traced oh the drum of the indicator, as it con-
tinues to operate in its usual way. Thus the explosion-
288 GAS-ENGINES AND PRODUCERS
recorder renders it possible to control the operation of
engines, to obtain some idea of the cause of defects and
to attribute them to the proper force. Improvements
can then be made which will ensure a greater efficiency.
A number of records herewith reproduced illustrate the
defects in the controlling apparatus and in the construc-
tion of certain engines, and also the result of improve-
ments which have been made on the basis of the records
obtained. The smaller lines indicate the compression,
which is usually constant in engines in which the " hit-
and-miss " system of governing is employed, while the
larger lines indicate the explosions. These records are
only part of the complete data normally drawn on the
i
284.4 Ibs.
EXPLOSIONS
BY THE ENGINE
ENGIHE .RUNNING
WITH NO LOAD
FIG. 146. Record with automatic starter.
paper in the period of 120 seconds corresponding with
an entire revolution of the recorder-drum.
The first record was taken while starting up an en-
gine provided with an automatic starting device and
supplied with explosive mixture without previous com-
pression (Fig. 146). The gradual lessening of the dis-
tances of the ordinates or lines representing the explo-
sions shows that the speed of the motor was slowly
increasing, and also indicates the time which elapsed
before the engine was running smoothly. The records
that follow (Figs. 147, 148 and 149) show the results
SELECTION OF AN ENGINE 289
m
which can be obtained with the recorder by correcting
the errors due to faults in installing the engine and its
1
WITH TOO LONG AN EXHAUST-PIPE,
BY WHICH THE PRODUCTS OF
COMBUSTION WERE RETAINED
AFTER CHANGING THE EXHAUST
FIG. 147. Gas-engine 'running at one-half load.
accessories. The fifth record is particularly interesting
because it shows the influence of the ignition-tube on
355.5 Ibs.
21_3 1 3
99.5
I
WITH INADEQUATE GAS-PIPE AFTER INSERTING A LARGER GAS-PIPE
The Xorman W. Henley Pub. Co.
FIG. 148. Record made after correcting faults.
the power of the deflagration of the explosive mixture
(Fig. 150). This record was obtained with an engine
BECAUSE OF THE SMALL CROSS SECTION OF THE PIPES
THE EXPLOSIONS ATTAIN THEIR MAXIMUM EE ^ ECT
FIG. 149. Record made after correcting faults.
provided with two contiguous tubes. The communica-
tion of each of these tubes with the explosion-chamber
290 GAS-ENGINES AND PRODUCERS
could be cut off at will at any moment. The last record
(Fig. 151) was obtained at a time when the effective
load of the engine was changed at two different inter-
vals. This record shows how regularly the engine was
running and how constant were the initial pressures.
These pressures, however, which is the case in most
engines, manifestly diminish when the explosions suc-
ceed one another without idle strokes of the piston.
This shows, also, the influence of " scavenging " the
products of combustion and the effect it has on the
efficiency of explosion-engines.
Analysis of the Gases. It has already been stated
that one of the tests which should be made consists in
measuring the calorific value of the gas. Just what the
calorific value of the gas may be it is necessary to know
in order to obtain some idea of the thermal efficiency of
the installation. If a suction gas-producer be employed
(an apparatus in which the nature of the gas generated
changes at each instant), calorimetrical analyses are in-
dispensable in appreciating the conditions under which
a generator operates.
These analyses are made by means of calorimeters
which give the calorific value either at a constant
pressure or at a constant volume.
Constant-volume instruments give a somewhat
w r eaker record than constant-pressure instruments; but
according to Professor Aime Witz, the inventor of an
excellent calorimeter, the constant-volume type is al-
most indispensable in gaging the efficiency of explo-
sion-engines.
EXPLOSION-RECORDS
291
! i
I
a
1
H
J I
K ^
Q *'
1
292 GAS-ENGINES AND PRODUCERS
The Witz Calorimeter. The accompanying dia-
gram (Fig. 152) illustrates Professor Witz's instru-
ment. Its elements are a steel cylinder having an inte-
rior diameter of 2.36 inches, about a thickness of 0.078
inch and a height of about 3.54 inches, so that its capac-
ity is about 15.1 cubic inches, and two covers screwed
on the cylinder to seal it hermetically, oiled paper be-
ing used as a washer. The upper cover carries a spark-
FIG. 152. The Witz calorimeter.
exciter; the lower cover is provided with a valve which
discharges into a cylindrical member 1.06 inches in
diameter. This second cover is downwardly inclined
at its circumference toward the center to insure com-
plete drainage of the mercury used for charging the
calorimeter. All surfaces are nickel plated. The
proportions of nickel and of steel are fixed by the
manufacturer so as to render it possible to calculate the
displacement of the apparatus in water. The calo-
rimeter having been completely filled with mercury is
inverted in this liquid in the manner of a test tube. The
THE WITZ CALORIMETER 293
; '0
explosive mixture is then introduced, being fed from
a bell in which it has previously been prepared. A
rubber tube connects the bell with the instrument.
The gas is forced from the bell to the calorimeter by
the pressure in the bell. The conical form of the bot-
tom causes the calorimeter to be emptied rapidly and
to be refilled completely with explosive gas at a pres-
sure slightly above that of the atmosphere. Equi-
librium is re-established by manipulating the valve,
during a very short interval, so as to permit the excess
gas to escape. During this operation the calorimeter
must be maintained in the vertical position shown in the
diagram. The atmospheric pressure is read off to one-
tenth of a millimeter (0.003936 inches) on a barometer.
The temperature of the gas may be taken to be that of
the mercury-vessel.
The explosive mixture is prepared in the water res-
ervoir, the glass bulb shown in the accompanying illus-
tration being employed. This bulb is closed at its
upper end by means of a cock and is tapered at its lower
end. The gas or air enters at the top by means of a
rubber tube and gradually displaces the water through
the lower end. The bulbs have a volume varying from
200 to 500 cubic centimeters (12 to 30 cubic inches),
and the error resulting from each filling of a bulb is
certainly less than 15 cubic millimeters (0.0009 cubic
inches) . The contents are emptied into a bell by lower-
ing the bulb into the water and opening the cock. If
seven bulbfuls of air be mixed with one bulbful of gas,
an explosive mixture of i to 7 is produced, this being
294 GAS-ENGINES AND PRODUCERS
the proportion commonly employed for street-gas. For
producer-gases the preferred proportion is i to i, oxy-
gen being often added to the air in order to insure com-
plete combustion.
The calorimeter, after having been filled, is placed
in a vessel containing a liter (1.7598 pints) of water
so that it is completely immersed. A spark is then
allowed to pass. The explosion is not accompanied by
any noise; the temperature rises a fixed- number of
degrees, so that the quantity of heat liberated can
easily be computed. Each division of the thermometer
is equal to 0.01502 C. The scale reading is minute,
each interval being divided by ten, so that readings to
the i, ^ooth part of a degree can be taken.
It should be observed that the mixture generated in
the reservoir is saturated with water vapor at the tem-
perature of the reservoir. Consequently, the vapor
generated by the explosion must condense in the calo-
rimeter if the final temperature of the calorimeter is the
same as that of the water reservoir. If, on the other
hand, the temperature be slightly different, a correction
must be made ; but the error is negligible for differences
in temperature of from 2 to 3 degrees C. (3.6 to
5.4 degrees F.). This, however, is never likely to
occur if the operation is conducted under favorable
conditions.
This apparatus is exceedingly simple and practical.
It does not require the manipulation of a pump. The
pressure of the mixture is read off on the barometer; the
calorimeter is entirely immersed in the water of the
or THE
UNIVERSITY*
OF
MAINTENANCE OF PLANTS
i
outer vessel, so that all corrections of doubtful accuracy
are obviated. The method requires but a very slight
correction for temperature. Air, alone or mingled with
oxygen, or a mixture of air and oxygen, can be easily
tested with.
Maintenance of Plants. If it should be necessary
to retain a consulting engineer to install an engine
capable of filling all requirements, it is also necessary
to select a careful attendant in order that the engine
may be kept in good condition. It is a rather wide-
spread belief that a gas-engine can be operated without
any care or inspection. This belief is all the more
prevalent because of the employment of street-gas en-
gines, which, by reason of their simplicity of construc-
tion and regularity of fuel supply, often run for several
hours, and even for an entire day, without any attention
whatever. But this negligence, particularly in the case
of engines driven from producers, is likely to produce
disastrous results. Although engines of this type do not
require constant inspection during operation, still they
require some attention in order that the speed may be
kept at a fixed number of revolutions. Moreover,
the care of the engine, the cleaning of the valves and of
the various parts which are likely to become dirty, and
the examination and cleaning of pipes, should be ac-
complished with great care and at regular intervals.
This task should be entrusted only to a man of intelli-
gence. A common workman who knows nothing of
the care with which the parts of an engine should be
handled is likely to do more harm than good.
296 GAS-ENGINES AND PRODUCERS
The factory owner who follows the instructions
which have been given in this book will avoid most of
the stoppages and the trouble incurred in engine and
generator installations, and may count upon a steadiness
of operation comparable with that of a steam-engine.
TEST OF A "STOCKPORT" GAS-ENGINE WITH
DOWSON PRESSURE GAS PLANT
Made by R. Mathot at the Works of the "Union Electrique*
C ie , Brussels, June 27, 1901
Piston Diameter : i$%". Piston stroke, 22".
Normal number of revolutions, 210.
1. Calorific value of the coal ^750 B.T.U.
2. Nature and origin of fuel: Anthracite coal
of Charleroi (Belgium).
3. Cost of fuel per ton -at the mine .... $5.50
4. Cost of fuel per ton at the plant .... $6.39
5. Fuel consumption per hour in the generator . 46.3 Ibs.
6. Fuel consumpton per hour in the boiler . 7 Ibs.
7. Proportion of ash in the coal .... 6 per cent.
8. Weight of steam at 66 Ibs. generated per
hour 42.7 Ibs.
9. Average brake horse-power 53 B.H.P.
10. Fuel consumption for gas per B.H.P. per
hour "... 0.875 Ibs.
11. Fuel consumption for steam per B.H.P. per
hour - J 33 Ibs.
12. Total fuel consumption 1.008 Ibs.
13. Steam consumption at 66 Ibs. pressure . 0.8 1 Ibs.
14. Gas pressure at the engine i|4 inches
15. Weight of water per B.H.P. per hour for
cooling the cylinder entering at 68 F.
and leaving at 105 F 51.5 Ibs.
TEST OF A STOCKPORT ENGINE 297
t
16. Corresponding heat absorbed in cooling . T 97O B.T.U.
17. Average initial explosive pressure on piston 324 Ibs.
18. Average pressure on piston per square inch 72 Ibs.
19. Average indicated horse-power with 85 per
cent, misses . . 92.5 I.H.P.
20. Corresponding mechan cal efficiency . . 84 per cent.
21. Corresponding electric load 31.950 K.W.
22. Cost of B.H.P. per hour in anthracite . . $0.0029
23. Cost of kilowatt per hour in anthracite . . $0.0048
24. Electric power generated per B.H.P. . . 602.8 W.
25. Thermal efficiency at 53 B.H.P. with 85
per cent, explosions 18.5 per cent.
TEST OF A 20 H.P. WINTERTHUR ENGINE
With Winterthur Suction-Producer made by R. Mathot at Winter-
thur, June 4 and 5, 1902
DATA OF TESTS WITH ILLUMINATING GAS AND WITH FUEL GAS
Dimensions of Winterthur Engine Piston diameter: 10^/6". Stroke:
i6fa". Compression: 177 pounds per square inch. Regulation:
hit and miss. Ignition: electro-magnetic. Fly-wheel: normal,
with external bearing. Lubrication of piston: with oil-pump.
Of main bearings, with rings (as in dynamos).
FULL LOAD WITH STREET-GAS
1. Number of revolutions per minute . . . 200
2. Corresponding number of explosions . . 96 per cent.
3. Net load on brake 120 Ibs.
4. Corresponding effective power .... 22 B.H.P,,
5. Mean initial explosive pressure on piston
per square inch 455 Ibs.
6. Average pressure on piston per square inch 78 Ibs.
7. Gas consumption per B.H.P. at 24 C. and
721 mm. mean pressure 15*5 cubic feet
8. Gas consumption per B.H.P. reduced to
o C. and 760 mm. mean pressure . . 13.5 cubic feet
298 GAS-ENGINES AND PRODUCERS
HALF LOAD WITH STREET-GAS
9. Number of revolutions per minute . . . 204
10. Corresponding number of explosions . . 60 percent.
11. Net load on brake 60 Ibs.
12. Corresponding effective power .... n.6 B.H.P.
13. Gas consumption per B.H.P. per hour at
24 C. and 721 mm. mean pressure . . 21 cubic feet
14. Gas consumption per B.H.P. per hour at
o C. and 760 mm. mean pressure . . 18.3 cubic feet
RUNNING WITH NO LOAD WITH STREET-GAS
15. Number of revolutions per minute . . . 206
16. Corresponding number of explosions . . 22 per cent.
17. Total gas consumption per hour at 24 C.
and 721 mm. mean pressure .... 106 cubic feet
1 8. Maximum calorific power of gas per cubic
foot 598 B.T.U.
19. Thermal efficiency with 96 per cent, explo-
sions 31 percent.
20. Mechanical efficiency with 96 per cent, ex-
plosions 82 per cent.
21. Temperature of water at the jacket-inlet . 75 degs. F.
22. Temperature of water at the jacket-outlet 130 degs. F.
23. Compression per square inch on piston sur-
face 178 Ibs.
24. Pressure after expansion 37 Ibs.
TEST OF WINTERTHUR PLANT WITH PRODUCER-GAS
1. Nature of fuel. Belgian an- hracite, "Bonne
Esperance et Batterie"; size, ^ inch.
2. Chemical composit on : Carbon, 86.5 per
cent.; hydrogen, 3.5 per cent.; oxygen
and nitrogen, 4.65 percent.; ash, 5.35 per
cent.
3. Calorific value per pound of coal . . . 14200 B.T.U.
TEST OF A WINTERTKUR PLANT 299
4. Net calorific value per pound of fuel . . 15050 B.T.U.
5. Price of anthracite delivered at the plant . $3-5O per ton
6. Number of revolutions of engine per minute 200
7. Corresponding number of explosions . 91 percent.
8. Load on brake . . . . :.;. . . . 106 Ibs.
9. Corresponding effective horse-power . . 20.2 B.H.P.
10. Fuel consumption at the generator per hour 16.4 Ibs.
11. Fuel consumed per B.H.P. per hour . . 0.81 Ibs.
12. Proportion of ash resulting from the tests . 6 per Cent.
13. Mean initial explosive pressure per square
inch . . , . 4 T 9-5 Ibs.
14. Average pressure on piston per square inch 72.5 Ibs.
15. Indicated horse-power with 91 per cent, ex-
plosions . . . . 25.4 I.H.P.
16. Mechanical efficiency . . ... . . 79 percent.
17. Thermal'efficiency at the producer ... 22 percent.
1 8. Water consumption per hour in the scrubber 66 gals.
19. Cost per B.H.P. per hour in anthracite . 62 gals.
TEST OF A 60 B.H.P. GAS-ENGINE, TYPE G 9, WITH
A SUCTION-GAS PLANT OF THE GASMOTOREN
FABRIK DEUTZ
(Made at Cologne, March 15, 1904, by R. Mathot.)
DATA OF THE TESTS
Diameter of Piston = 16.5". Piston Stroke = 18.9"
FULL LOAD
1. Average number of revolutions per minute 188.66
2. Corre ponding effective work . . . . 65.11 B.H.P.
3. Average compression per square inch . 176 Ibs.
4. Average ;n tial explosive pressure per square
inch . 397 Ibs.
5. Average final expansion pressure ... 25 Ibs.
6. Vacuum at suction . . . . . . . 4 .4 Ibs.
7. Average pressure on piston 81 Ibs.
^8. Corresponding indicated horse-power . . 77 I.H.P.
300 GAS-ENGINES AND PRODUCERS
FUEL
9. Nature of fuel : Anthracite coal 0.4" to 0.8"
10. Origin: Coalpit of Ze he, Morsbach at Aix-
la-Chape le.
11. Chemical composition of coal :
Carbon . . . . 83 .22 % Sulphur . . . o .44 %
Hydrogen . . 3 .31 % Ash .... 7 .33 %
Nitrogen and Oxygen 3 .01 % Water ... 2.69 %
12. Calorific value. . . ..... , .'".'" 13650 B.T.U.
GAS
13. Chemical composition of gas:
Carbonic acid . 6.60 % Methane. . . 0.57 %
Oxygen . . \ o .30 % Carbon monoxide 24 .30 %
Hydrogen . . 18 .90 % Nitrogen ... 49 .33 %
14. Calorific value of gas, combination water,
at 59 F. constant vo ume reduced to
32 F. and atmospheric pressure . ' . . 140 B.T.U.
TEMPERATURES
Engine
15. Cooling water at the inlet of the cylinder-
head . . .'. . . . . < 554 deg. F.
Temperature at the outlet . . -. . 109 .5 deg. F.
16. Temperature at outlet of cylinder . . . 127.5
Gas-Generator
17. Temperature of water in the vaporizer . . 158.3 deg. F
EFFICIENCIES AND CONSUMPTION
18. Mechanical efficiency . . . . .i < . 84.6 %
19. Gross consumption of coal per B. H. P. per
hour ...... . ., . . . 0.86 Ibs.
20. Thermal efficiency in proportion to the ef-
fective work and the gross consumption
of coal in the gas-generator . * . . 24 .3 %
TEST OF A DEUTZ PLANT 301
HALF LOAD
WORK
1. Average number of revolutions per minute 195 .5
2. Corresponding effective work .... 33 .85 B.H.P.
3. Corresponding average compression . .125 Ibs.
4. Average initial explosive pressure . . . 258 Ibs.
5. Average final expansion ... . . . 18 Ibs.
6. Vacuum at suction . . . ! .. . . . 6.8 Ibs.
7. Average mean pressur on piston . . . 46 .2 Ibs.
8. Corresponding indicated power .... 45 . I.H.P.
9. Speed variation between full and half load 3 .5 %
CONSUMPTION
jo. Gross consumption of coal per B.H.P. per
hour .. . . . . . . . . . . 1-155 Ibs.
RUNNING WITH NO LOAD
1. Average number of revolutions per minute 199
2. Minimum corresponding compression . . 95 .55 Ibs.
3. Average initial explosive pressure . . . 220 Ibs.
4. Average final expansion . ... . ..*.' o Ibs.
5. Vacuum at auction . . . . . . . 8.8 Ibs.
6. Average pressure on piston . . . . . u .2 Ibs.
7. Corresponding indicated horse-power . n I.H.P.
8. Speed variation between full load and no
load .. . . . .' / . " . . . -. 5.2 %
TEST OF A GAS PLANT OF A FOUR-CYCLE DOUBLE-
ACTING ENGINE OF 200 H.P. AND A SUCTION-PRO-
. DUCER IN THE WORKS OF THE GASMOTOREN
FABRIK DEUTZ, COLOGNE
March 14 and 15, 1904, by Me rs. A. Witz, R. Mathot, and de
Herbais
DATA OF THE TESTS
Piston Diameter: 21 ^". Stroke: 27^". Diameter of Piston-Rods:
front, 424"; rear, 4 T 5 /
3 02 GAS-ENGINES AND PRODUCERS
ENGINE
Full Load Tests
1. Average number of revolutions per minute 151.29 and 150.20
2. Corresponding effective load . 214.22 B.H. P. and 222.83 B.H. P.
3. Duration of the tests . .... . . 3 hours and 10 hours
4. Average temperature of water after cooling
the piston ....". . . ... 117.5 deg. F.
5. Average temperature of water after cool-
ing the cylinder and valve-seats . . % 135 deg. F.
6. Water consumption per hour for cooling the
piston J - v- ' . 39g al -
PRODUCER
7. Nature and Origin of Fuel: Anthracite
coal " Bonne-Esperance et Batterie"
Herstal, Belgium.
8. Calorific value of fuel 14650 B.T.U.
9. Consumption of fuel per hour (plus 53 Ibs.
on the night of the I4th for keeping the
generator fired during 14 hours, the en-
gine being stopped) 199 Ibs. 160 Ibs.
10. Water consumption per hour in the vapor-
iser . r . . . . 14.2 gals.
11. Water consumption per hour in the scrub-
bers . . 318 gals.
12. Average temperature of gas at the outlet
of the generator 55^ ^eg. F.
13. Average temperature of gas at the outlet
of the scrubbers ' . . 62.5 deg. F.
EFFICIENCIES
14. Gross consumption of coal per B.H. P. per
hour 0.927 Ibs. 0.720 Ibs.
15. Consumption of coal per B.H. P. after de-
duction of the water ... . . . 0.907 Ibs. 0.705 Ibs.
TEST OF A 200 H.P. DEUTZ PLANT 303
1 6. Thermal efficiency relating to the effective
H.P. and to the dry coal consumed in
the generator ........ 19 % 244 %
17. Water consumption per B.H.P. hour:
For the cylinder, stuffing-boxes and valve-
seat jackets ........ 4.65 gals.
For the piston and piston-rods . . 1.75 gals.
For the vaporizer 0.0655 g a ^ s -
For washing the gas in the scrubbers . 1.42 gals.
1 8. Water converted in steam per Ib. consumed
in the generator - l 93 g a ^ s -
INDEX
Adjustment of gas-engine, 126
Adjustment of moving parts, imper-
fect, 146
Admission -valve, binding of, 152
Admission, variable, 55, 56
Air-blast, 180
Air-chest, 82
Air, displacement of, 92
Air, exclusion of, in producers, 207
Air, filtration of, 82
Air-heater, Winterthur, 236
Air-heaters, 238
Air-pipe, 82
Air-pipe, location of, 83
Air-pump, 266
Air, regulation of supply, 82
Air suction, 81
Air suction, resistance to, 82
Air supply of producer, 225
Air-valve, control by engine, 25
Air vibration, 92
Alcohol as engine fuel, 264
Anthracite, consumption of, in pro-
ducers, 200
Anthracite in producers, 190, 201
Anti-pulsators, 77
Anti-pulsators, disconnection of, in
stopping engine, 132
Anti-pulsators, precautions to be
taken with, 79
Anti-vibratory substances, 89
Ash-pit, 214, 217
Ash-pit, Bollinckx, 220
Ash-pit, cleaning of, 261
Ash-pit, Deutz, 220
Ash-pit, door of, 220
Ash-pit, Wiedenfeld, 220
Asphyxiation, 169
Atomizer of oil-engines, 265
B
Back firing, 82, 131
Back pressure to exhaust, 151
Bags, arrangement of, 80
Bags, capacity of, 79
Bags, precautions to be taken with, 79
Bags, rubber, 77
Bark as producer fuel, 193
Batteries for ignition, 31
Bearings, adjustability of, 5
Bearings, adjustment of, 44
Bearings, care of, 123
Bearings, lubrication of, 117
Bearings, material of, 51
Bearings of fly-wheels, 92
Bearings, overheated, 146
Bearings, over-lubricated, 150
Bearings, position of, 44
Bell, gas-holder, 187
Bell, Pintsch, 248
Bell, volume of, 187
Belts, prevention of adhesion by oil,
120
Benier, E., 199
Benzin as engine fuel, 264
Binding, 147
Blast in producers, 180, 193, 225
Blower, Koerting, 181
Blower, Root, 182, 188
Blowers for producers, 181
Blowing-generators, 169
Bolts of foundation, 91
Bomb, Witz, 284, 292
Boughs for coolers, 108
Box, charging, 221
Box, double closure for charging, 222
Box, removable charging, 225
Brake tests, 284
Branch pipes, minimum diameter of,
81
Bricks for foundation, 91
Brushes, lifting of, when dynamo-
engine is stopped, 132
Brush, purifying, 250
Burner of hot tube, how ignited, 128
Burner, regulation of fixed, 144
Bushings, care of, 123
Bushings, fusion of, 147
Bushings (see also Bearings)
305
3 6
INDEX
Calorimeter, Witz, 292
Calorimeters, 284, 290
Cam, half-compression, 130, 132
Cam, relief, 130
Cams, 51
Caps of valve-chests, 124
Carbureter, 266
Care during operation of engine, 131
Casing, independence of frame, 42
Charging a producer, 221
Charging the generator, 259
Chest for exhaust, 83
Circulation of water, 98, 125
Circulation of water, how effected,
102
Circulation of water in tanks, 105
Circulation of water, regulation of,
107
Cleaning of producer, 261
Cleanliness, necessity of, 121
Cleanliness of producers, 1 79
Closures for charging-boxes, 223
Coal in producers, 201
Coal in producers, bituminous, 195
Coal, Pennsylvania, 203
Coal (see also Anthracite)
Coal, Welsh, 203
Cock, Deutz, 224
Cock, Pierson, 224
Cock for charging-box, 223, 224
Coke in producers, 201
Coke in washers, 242
Combustion -generators, 193
Combustion, inverted, 195
Compression, determination of, 273
Compression, faulty, 134
Compression, high, 154
Compression in Banki engine, 264
Compression in Diesel engine, 264
Compression, losses in, 143
Compression period, 21
Compression, relation to power de-
veloped, 122
Compressors for producers, 182
Connecting-rod bearings, 45
Connecting-rod bearings, rational de-
sign of, 45
Connecting-rod, lubrication of, 113,
TI 5
Consulting engineer, advisability of
retaining, 282
Consumption at half load and full
load, 62
Consumption at various loads, 62
Consumption in double or triple act-
ing engines, 62
Consumption of gas, 173
Consumption of gas in burner, 30
Consumption of suction -producers,
200
Consumption per effective horse-
power, 62
Cooler for gas, 199
Cooler, for producer, 240
Coolers, 107
Coolers, size of, 109
Cooling of cylinder, 98, 100, 156
Cooling of producer-gas engines, 203
Cooling, thermo-siphon, 100
Cost of oil and volatile hydrocarbon
engines, 268
Crank-pin, tensile strength of, 51
Crank -shaft, 50, 51
Crank -shaft bearings, 44
Crank -shaft bearings, design of, 46
Crank -shaft, effect of premature ex-
plosion on, 30
Crank-shaft lubrication, 117
Crank-shaft, material of, 50
Crosshead, care of, 123
Cycle, analysis of, 276
Cylinder, arrangement of, 41 .
Cylinder, cleaning of, 122
Cylinder, cooling of, 156
Cylinder, evacuation of, 83, 131
Cylinder, gravel in, 137
Cylinder, grinding of, 42
Cylinder, incandescent particles in,
142
Cylinder, independence of casing,
42
Cylinder-jacket (see Water-jacket)
Cylinder lubrication, 112
Cylinder-oil, 112, 149
Cylinder, overhang in horizontal en-
gines, 42
Cylinder, overheating of, 148
Cylinder, presence of water in, 136
Cylinder-sheir, 41
Cylinder, smoke from, 149
Cylinder, temperature during opera-
tion of engine, 132
Cylinder, thrust of, 43
Cylinder, tightness -of, 122
INDEX
37
Damper, Pintsch, 224
Dampers, 223
Detonations, untimely, 141
Distributing mechanism, derange-
ment of, 152
Drain-cock in gas-pipes, 70, 75
Drain-cocks, testing of, 256
Drier for producer-gas, 248
Dust-collector, 239
Dust-collector, Benz, 239
Dust-collector, Bollinckx, 239
Dust-collector, Pintsch, 239
Dust-collector, Wiedenfeld, 239
Dynamo, lifting brushes from, in stop-
ping engine, 132
Ebelmen principle, 195
Engine, Banki, 264
Engine, Diesel, 264
Engine, producer-gas and steam, com-
pared, 203
Engine, selection of, 279
Engine, starting a producer-gas, 258
Engineer, duty of a consulting, 281
Engines, governing oil, 265
Engines, oil, 264, 265
Engines, producer-gas, 153
Engines, producer-gas, temperature
of, J 57
Engines, specifications of, 281
Engines, speed of oil, 264
Engines, tests of, 268
Engines, volatile hydrocarbon, 264,
267
Engines, writers on oil, 266
Escape-pipes, 228
Essences, 264
Exhaust, 83
Exhaust, back pressure to, 151
Exhaust, determination of resistance
to, 274
Exhaust into sewer or chimney, 85
Exhaust, noises of, 94, 141
Exhaust period, 22
Exhaust, water in, 136
Exhausters, 183
Exhaust-chest, 83
Exhaust-muffler, 86, 94
Exhaust -pipe, 83, 85
Exhaust-pipe, design of, 96, 97
Exhaust-pipe, joints for, 85
Exhaust-pipe, oil in, 151
Exhaust -valve, binding of, 152
Exhaust-valve, cooling of, 25
Expansion -boxes, 95
Expansion period, 22
Expert, necessity of an, 282, 283
Explosion, spontaneous, 140
Explosion -engines (see Gas-engines)
Explosion period, 22
Explosion -recorder, analysis of inertia
of, 277
Explosion -recorder for industrial en-
gines, 285
Explosion -recorder, the continuous,
269
Explosions, comparison of average
force of, 275
Explosion-records, 288
Explosions, retarded, 143
Fans for producers, 181
Feeder, Winterthur, 236
Feed-hopper, 224
Firebox, door of, 221
Flues, escape, 228
Fly-wheel, oil on, 120
Fly-wheel, starting the, 131
Fly-wheels, 46
Fly-wheels as pulleys, 46
Fly-wheels, balancing of, 46
Fly-wheels, curved spoke, how
mounted, 49
Fly-wheels, fastening of, 46
Fly-wheels, proper mounting of, 46
Fly-wheels, rim of, 46
Fly-wheels, single, 48, 92
Fly-wheels, single, for dynamo-en-
gines, 46
Fly-wheels, straight and curved
spoke, 49
Fly-wheels with hit- and- miss system,
5
Foundation, 44, 87
Foundation, design of, 88, 89
Foundation, excavation for, 88
Foundation, insulation of, 89, 90
Foundation of dynamo-engine, 91
3 8
INDEX
Frame, 43
Frame, method of securing, to foun-
dation, 44
Fuel of producers, 178, 187, 254
Fuel, qualities of, 201
Fuel (see also Lignite, Peat, Sawdust,
Wood, Coal, etc.)
Fuel, size of, 201
Fuel, smoke-producing, 254
Gas, ascertaining purity of, 128
Gas, blast-furnace, 153
Gas, calorific value of, 284
Gas, calorific value of producer,
200
Gas, coke-oven, 153
Gas consumption, 173
Gas consumption of burner, 30
Gas, effect of quality, 152
Gas-engine, balancing of, 46
Gas-engine, care during operation,
I 3 I
Gas-engine, cost of installation, 19
Gas-engine, cost of operation, 19
Gas-engine, difficulties in starting,
i34
Gas-engine, how to start a, 128
Gas-engine, how to stop a, 132
Gas-engine, installation of a, 68
Gas-engine, location of a, 68
Gas-engine, selection of a, 21
Gas-engine, simplicity of installation,
J 7
Gas-engine, the four-cycle, 21
Gas-engines, adjustment of, 126
Gas-engines, care of, 121
Gas-engines, " Steam -Hammer," 57
Gas-engines, temperature of, 158
Gas-engines, tests of, 283
Gas-engines, vertical, 56
Gas-engines, writers on, 68
Gas, fuel, 153
Gas-holder, 186, 189
Gas-holders, 247
Gas-holder, combined with washer or
scrubber, 186
Gas, illuminating (see Street-gas)
Gas, impurities of, 172
Gas, Mond, 153, 167
Gasometer (see Gas-holder)
Gas, producer (see Producer-gas)
Gas production, 1 73
Gas, purification of wood, 195
Gas supply, necessity of coolness,
69
Gas-valve, necessity of independent
operation of, 27
Gas, water, 153, 169
Gas, wood, 153, 168
Gases, analysis of, 290
Generator (see also Producer)
Generator, Benz, 207
Generator, Bollinckx, 207
Generator, care of, 259
Generator, charging the, 259
Generator, construction of, 177, 207
Generator, dimensions of, 252
Generator, Dowson, 177
Generator, firing the, 205, 256
Generator, hot operation of, 252
Generator of suction producer, 205
Generator, operation of, 251
Generator, Pierson, 215
Generator, Pintsch, 207
Generator, Taylor, 207
Generator, Wiedenfeld, 207
Generator, Winterthur, 207
Generator with internal vaporizer,
206
Generators, blowing, 169
Generators, pressure, 169, 177
Governor, ball, 52, 53
Governor, care during operation,
I 3 I
Governor, hit-and-miss, 52, 54
Governor, inertia, 53
Governor, sensitiveness of, 52
Governors, 53
Governors, adjustment of, 124
Governors, care of, 123
Governors, centrifugal, 56
Governors, centrifugal, with hit-and
miss regulation, 55
Governors for oil-engines, 265
Governors for producer-gas engines,
161
Governors, hit-and-miss, 54
Governors, variable admission, 56
Grate, Benier's, 216
Grate of generator-lining, 214
Grate, Kiderlen, 216
Grate, Pintsch, 216
Grate, Wiedenfeld, 216
INDEX
39
H
Heater, air, 238
Hit-and-miss regulation (see Gov-
ernors)
Holders, gas, 247
Hopper, Bollinckx, 225
Hopper, Deutz, 225
Hopper for generator, 224
Hopper, removable feed, 225
Hopper, Taylor, 225
Hopper, Wiedenfeld, 225
Hopper, Winterthur, 225
Horse-power, definition of, 60
Horse-power, determination of, 61
Horse-power (see also Power)
Hot tubes (see Tubes)
Hydrocarbons, volatile, for engine
fuel, 264
Ignition, 27, 122
Ignition, adjustment of, 144
Ignition by battery and coil, 31
Ignition by magneto, 33
Ignition, curing defects of electric,
J 45
Ignition, defective, 152
Ignition, disadvantages of belated,
28
Ignition, disadvantages of prema-
ture, 28
Ignition, effect of lost motion, 146
Ignition, effect of mixture composi-
tion on, 28
Ignition, effect of temperature of
flame on, 28
Ignition, effect of water on, 136
Ignition, electric, 30, 139
Ignition, electric, regulation of, 145
Ignition, faulty, 143
Ignition for high -pressure engines, 35
Ignition, hot-tube, 159
Ignition, imperfect, 137
Ignition, objections to electric, 31
Ignition of producer-gas, 160
Ignition, premature, 139, 142
Ignition, premature, in high-pressure
engines, 158
Ignition, prevention of, by faulty com-
pression, 134
Ignition, proper timing of, 27
Ignition, spontaneous, 140, 159
Ignition, tests prior to starting en-
gine, 129
Ignition -tubes (see Tubes)
Incrustation of water-jacket, 98, 148
Incrustation, prevention of, 107
Incrustations, 255
Indicators, 285
Indicator-records, 127
Induction-coil, 32
Installation, laws governing gas-
engine, 86
Joints, 125
Joints, care of, 124
Laming mass, 246
Laws governing gas-engines, 86
Leakage of pipes, 69
Lift -valve for charging-box, 223
Lignite in producers, 188
Lining, refractory, 211
Lining, support for generator, 214
Loads, consumption at half and full,
62
Location of engine, 68
Lubricate (see Oils)
Lubricating-pumps, 115
Lubrication, in, 121
Lubrication, difficulties entailed by,
119
Lubrication, faulty, 149
Lubrication of crank-shaft, 117
Lubrication of high -power engine,
116
Lubrication of valve-stem, 119
Lubricator, cotton-waste, 117
Lubricators, automatic, 113
Lubricators, disconnection of, when
stopping engine, 132
Lubricators, examination of, before
starting, 129
Lubricators, feed of, 121
Lubricators, revolving-ring, 118
Lubricators, sight-feed, 118
Lubricators, types of, 113
3-ro
INDEX
M
Magneto, adaptability for producer-
gas, 35
Magneto, control of, 38
Magneto, efficiency of, 34
Magneto -igniter, construction of, 35
Magneto ignition, 33
Magneto ignition, precautions to be
taken, 34
Magneto, inspection of, before start-
ing engine, 129
Magneto, mechanical control of, 33
Magneto, operation of, 33
Magneto, regulation of, 37
Maintenance of plants, 295
Manograph, 269
Mass, Laming, 246
Meters, capacity of, 70
Meters, dry, 72
Meters, evaporation in wet, 70
Meters, falsification of records, 70
Meters, inclination of, 71
Meters, size of, 71
Misfire, 137
Mixture, effect of high compression
in > 155
Mixture, effect of high pressure on,
156
Mixture, governing by varying the,
161-164
Mixture, poorness of, 143
Mixture, pressure of, 26
Mixture-valve, necessity of independ-
ence of operation of, 27
Mortar for foundation, 87
Motion, lost, 146
Muffler for exhaust, 86, 94
N
Naphthalene in gas-pipes, 70
Noises, cause of, 92
Noises of exhaust, 94
Oilers (see Lubricators)
Oiling (see Lubrication)
Oil, addition of sulphur to, 147
Oil, cylinder, 149
Oil-engines, 264, 265
Oil-engines, governing, 265
Oil-engines, speed of, 264
Oil-engines, writers on, 266
Oil for engine fuel, 264
Oil, freezing of, 150
Oil-guard for fly-wheel, 120
Oil-lamp, 266
Oil, prevention of spreading on fly-
wheel, 1 20
Oil-pumps, 115, 226
Oil, quality of, 150
Oil, splashing of, 119
Oil-tank, 266
Oils, how tested, 112
Oils, mineral for lubrication, 112
Oils, purification of, 113
Oils, quality of, 112
Oils, requisites of, 112
Operation, steadiness of, 52
Otto cycle, 21
Overheating, 152
Overheating, prevention of, 147
Pacini treatment, 171
Peat in producers, 188
Perturbations, 134
Petrol (see Oil)
Pipe-hangers, 86
Pipes, 69
Pipes, cross-section of, 70
Pipes, disposition of, 77
Pipes, escape, 228
Pipes, exposure to cold, 69
Pipes for exhaust, 83
Pipes for producer-gas, 249
Pipes for water-tanks, 102, 103, 105
Pipes, hanging of, 86
Pipes, insulation from foundations
and walls, 94
Pipes, leakage of, 69
Pipes, minimum diameter of branch,
81
Pipes, proper size of, 70
Piston, 39, 122
Piston, avoidance of insertions or
projections, 39
Piston, cleaning of, 141
Piston, curved faces inadvisable, 39
Piston, direct connection with crank-
shaft, 43
INDEX
Piston, finish of, 41
Piston, importance of, in
Piston, leakage of, 136
Piston, overheating of, 148
Piston, position of, in starting, 130
Piston, rear face of, 39
Piston-pin, construction of bearing
at, 40
Piston-pin, location of, 41
Piston-pin, locking of, 40
Piston-pin, lubrication of, 113
Piston-pin, material of, 40, 51
Piston-pin, strength of, 40
Piston-rings, fouling of, 149
Piston-rings, material of, 41
Piston-rings, number of, 41
Piston-rod, effect of premature ex-
plosion on, 30
Piston-wear, 40
Poisoning, carbon monoxide, 170
Porcelain of spark-plug, 32
Power, definition of, 60
Power, measuring engine, 285
Power, " Nominal," 61
Precautions to be taken in starting,
128
Pressure, back, to exhaust, 151
Pressure-generators, 169, 177
Pressure in producer-gas engines, 160
Pressure-lubricators, 114
Pressure-producers, 1 74
Pressure-regulator, bell as, 187
Pressure-regulators, 77
Pressure-regulators, their construc-
tion, 78
Pressures, high, in producer-gas en-
gines, 154
Preheaters, 229
Producer, assembling, 253
Producer, Benier, 216
Producer, Benz, 228, 239, 240
Producer, Bollinckx, 206, 220, 225,
228, 234, 239
Producer, Chavanon, 229
Producer, cleaning of, 261
Producer, Dawson, 174
Producer, Deschamps, 198
Producer, Deutz, 206, 220, 224, 225,
228, 229, 240
Producer, Deutz, 231, 232
Producer, Deutz lignite, 188
Producer, Duff, 195
Producer, Fange-Chavanon, 198
Producer, Fichet-Heurty, 240, 245
Producer, Gardie, 183
Producer-gas, 153
Producer-gas, 165
Producer-gas as a furnace fuel, 177
Producer-gas, calorific value of, 200
Producer-gas, composition of, 166
Producer-gas plants, tests of, 297
Producer-gas, writers on, 154
Producer, general arfangement of
suction, 204
Producer, Goebels, 206
Producer, Hille, 206, 239
Producer, Kiderlen, 206
Producer, Kiderlen, 216
Producer, Koerting, 232
Producer, Lencauchez, 212, 214
Producer, Phoenix, 217
Producer, Pierson, 224, 229
Producer, Pintsch, 206, 216, 224, 231,
232, 239, 245, 248
Producer, Riche, 168, 190, 193, 195,
216
Producer (see also Generator)
Producer, stoppage of, 261
Producer, Taylor, 206, 214, 225, 231,
232
Producer, test by smoke, 254
Producer, test of Deutz, 298
Producer, test of Dowson, 296
Producer, tests of Winterthur, 297
Producer, Thwaite, 195
Producer, Wiedenfeld, 206, 216, 220,
225, 234, 239
Producer, Winterthur, 225, 228, 236
Producers, advantages of suction,
199
Producers, combustion, 193
Producers, conditions of perfect oper-
ation, 251
Producers, consumption of suction,
200
Producers, distilling, 190
Producers, efficiency of, 201
Producers, efficiency of lignite, 190
Producers, efficiency of wood, 194
Producers, lignite, 188
Producers, maintenaace of, 254
Producers, peat, i8S
Producers, pressure, 174
Producers, self-reducing, 193
Producers, specifications of, 281
Producers, suction, 199
3 12
INDEX
Producers, suction (see also Suction-
producers)
Producers, tests of, 297
Producers with external vaporizers,
206
Production' of gas, 173
Pulley, disconnection of, in stopping
engine, 132
Pump, circulating with by-pass, 106
Purifier, fiber, 185
Purifier, Fichet-Heurtey, 245
Purifier, material for, 245
Purifier, moss, 185
Purifier, Pintsch, 245
Purifier, sawdust, 185
Purifiers for gas, 184
Purifiers for producer-gas, 244
Recorder, analysis of inertia of ex-
plosion, 277
Recorder, explosion, for industrial en-
gines, 285
Recorder, the continuous explosion,
269
Records of engines, 284
Records of explosions, 288
Records, indicator, 127
Regrinding of valves, 122
Regularity, cyclic, 48, 53
Remagnetization of magnetos, 33
Resuscitation after asphyxiation, 171
Retort, cleaning of, 225
Retort of producer, 190
Retort, support, 214
Revolutions, variations in number of,
52
Rollers, 51
Running, steadiness of, 52
Sand for foundation, 87
Sawdust in producers, 193
Scavenging, 142, 155
Scrubber, 189, 199
Scrubber, combined with gas-holder,
186
Scrubber for producer-gas, 240
Scrubber, size of, 253
Selection of gas-engine, 21
Shavings in producers, 193
Slide-valve for charging-box, 223
Slide-valve, its disadvantages, 23
Sluice-valves, 101
Smoke from cylinder, 149
Spark-plug, 32
Specifications -of engines, 281
Specifications of producers, 281
Speed, how to increase, 124
Speed of oil-engines, 264
Speed of volatile hydrocarbon en-
gines, 264
Speed, variation of, with load, 52
Spokes of fly-wheels, 49
Spring for valves (see Valves)
Springs, selection of, for explosion-
recorder, 277
Starter, Tangye, 65
Starting an engine, 128
Starting, automatic, 63, 130
Starting by compressed air, 64
Starting by hand, 63
Starting by hand-pumps, 64
Starting, difficulties in, 134
Starting, how accomplished, 66
Starting of producer-gas engine, 258
Steadiness, 52
Steam-engine, cost of installation, 19
Steam-engine, cost of operation, 19
Stoppage of producer, 261
Stopping the engine, 132
Stops, sudden, 151
Straw in producers, 193, 254
Street-gas, 165
Suction, determination of resistance
to, 274
Suction, noises caused by, 141
Suction of air, 81
Suction period, 21
Suction-producer, general arrange-
ment of, 204
Suction-producers, 199
Suction-producers, advantages of, 199
Suction-producers, efficiency of, 201
Suction-valve, leakage of, 142
Superheater, Winterthur, 236
Sylvester treatment, 171
Tanks, connection of, 105
Tanks, design of, 103
INDEX
Tanks, location of, 102
Tanks for water-jacket, how mounted,
101
Tar in producer-plants, 200
Tar, removal of, 250
Tar (see also Scrubber, Purifier, etc.)
Taylor, A., 199
Terminals of magneto apparatus, 34
Tests of gas-engine plants, 283
Tests of high-speed engines, 268
Tests of producer-gas engines, 297
Thrust-bearings, 51
Tongue, traction of, in asphyxiation
cases, 172
Tower, washer, 244
Town-gas (see Street-gas)
Tree branches for coolers, 107
Trepidations, 92
Tube, gas-supply pipe of incandes-
cent, 77
Tube, incandescent, 27
Tube, incandescent, adjustment of,
144
Tube, incandescent, breakage of, 137
Tube, incandescent, danger of break-
ing, 131
Tube, incandescent, how started,
128
Tube, incandescent, leakage of, 138
Tubes as vaporizers, 231
Tubes, incandescent, 28, 159
Tubes, incandescent, valved, 29
Tubes, use of special valves with in-
candescent, 29
Tubes, valveless ignition, 28
Valve-chests, 124
Valve mechanism, slide, 23
Valve-regrinding, 122, 135
Valve-stem lubrication, 119
Valves, 122
Valves, accessibility of, 25
Valves, cooling of, 25
Valves, cooling of, in high-pressure
engines, 156
Valves, defective operation of, 135
Valves, free, 27
Valves, mechanical control of, 27
Valves, modern, 24
Valves, necessity of cleanliness, 25
Valves, regulation of, before starting,
129
Valves, requisites of, 25
Valves, retardation in action of, 146
Vaporizer, Bollinckx, 234
Vaporizer, Chavanon, 229, 234
Vaporizer, Deutz, 231, 232, 229, 225
Vaporizer, Field, 233
Vaporizer, internal, 206
Vaporizer, Koerting, 232
Vaporizer, maintenance of, 255
Vaporizer, operation of, 234
Vaporizer, Pierson, -229
Vaporizer, Pintsch, 231, 232
Vaporizer-preheaters, 229
Vaporizer, size of, 253
Vaporizer, Taylor, 231, 232
Vaporizer, Wiedenfeld, 225, 234
Vaporizers, external, 206, 230
Vaporizers, internal, 229
Vaporizers, partition, 234
Vaporizers, regulation of, 236
Vaporizers, tubular, 231
Ventilation in engine-room, 69
Vibration, 89
Vibration of air, 92
Vibration, prevention of, 89, 90
W
Water circulation, 98, 107, 125
Water circulation by pump, 107
Water circulation, care during opera-
tion, 132
Water circulation, bow effected, 102
Water circulation, prevention of
freezing, 133
Water-coolers, 106
Water-coolers, size of, 109
Water for circulation, 99
Water for producer-gas engines, 203
Water-gas, 153, 167
Water in cylinder, 136
Water in exhaust, 136
Water-jacket, 41, 98, 125, 157
Water-jacket, incrustation of, 148
Water-jacket, outlet of, 98
Water-jacket, prevention of incrus-
tation, 107
Water-pipe, 102
Water, purification of, for circulation^
98
3H
INDEX
Water, running, for jacket, 98
Water-tanks, 101
Water-tanks, connection of, 103, 105
Water-tanks, design of, 103
Water-tanks, location of, 102
Washer, Benz, 240
Washer, combined with gas-holder,
186
Washer, Deutz, 240
Washer, Fichet-Heurtey, 240
Washer for gas, 199
Washer for producer-gas, 240
Washer, maintenance of, 256
Washer, material employed in, 242
Washer, Winterthur, 240
Washers, 184
Wear, premature, 146
Witz apparatus, 284
Wood as fuel, 254
Wood, calorific value, 194
Wood-gas, 153, 168
Wood-gas, purification of, 195
Wood in producers, 190, 192, 193
Work, definition of effective, 60
THE MIETZ & WEISS
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