no MODERN PAPER-MAKING
In fact, the action is about the nearest that can be obtained by mechanical
means to the pestle and mortar of the primitive paper-maker.
Although the power consumed is rather high compared to that of the
pulper for its output, it must not be forgotten that the pulp is not only defibred
but fibrillated, which is power saved in the beating engine. Therefore it is still
popular among paper-makers who are wise enough to recognise its value in
this respect. For some qualities of broke and waste paper it is a necessity,
such as imitation parchments, krafts, or other specially treated papers, which
it is nearly impossible to defibre by any other means. As against this, it has
the disadvantage of reducing to fine particles any foreign materials in the pulp.
These cannot then be got rid of very easily, as the fibres carry them round
the sand traps and through the strainers.
Also, the edge runner requires a very heavy and secure foundation and
constant and close attention from the engineer to ensure safety for the workers.
In dealing with miscellaneous waste paper, the edge runner produces results
which more than compensate for all its faults. A very important matter in
connectioij with the kollergang is its proper lubrication; it must be carefully
and regularly lubricated and the bearings kept cool, otherwise the stones may
crack and become useless.
In order to get the full value of broke from various qualities of paper, a
great deal of space is necessary.. It is obvious that the broke from an all-rag
paper is of much more value than that from an esparto printing, and to take
full advantage of that value, the former must be utilised in a similar paper.
This necessitates the broke being kept in separate lots until that, or a similar
variety, is again being made. This applies especially to coloured broke, which
may have to be kept separate for quite a long time.
Very few mills have space for this purpose, and a great deal of good quality
broke is sacrificed by being put into cheaper grades of paper.
All broke that is being kept for future use should be packed in good clean
bags or press packed into bales and stored in a dry place, well away from dust
and oily machinery. Before going into the boiler or pulper, all broke should
be passed over a sorting table with coarse wire mesh top, and well shaken
to get rid of dust and foreign material.
Bought waste paper requires to be sorted by skilled sorters in the same
way as rags, if it is to be used in good papers, even when bought from waste-
paper merchants who grade their paper into special qualities.
The Effect of adding Broke to the Furnish.—A great diversity of opinion is
observable among paper-makers as to the effects of adding repulped paper
to the furnish. No general statement can* in our opinion, be made. The
circumstances of each particular case may differ so much that quite opposite