The Manufacture of Paper: With Illustrations, and a Bibliography of Works Relating to Cellulose and Paper-MakingSindall, R. W. (Robert Walter)
History
The Manufacture of Paper: With Illustrations, and a Bibliography of Works Relating to Cellulose and Paper-Making
Sindall, R. W. (Robert Walter)
Papermaking
Some idea of the enormous quantity of material used for the daily
press may be judged from one or two examples. A certain popular weekly
newspaper having a circulation of one and a quarter million copies per
week requires every week 137 tons of paper produced from 170 tons of
wood. A popular halfpenny newspaper boasting a circulation of about
one-half million copies per day consumes 185 tons of paper manufactured
from 230 tons of wood, every week.
It is easy also from these facts to estimate the amount of timber
which must be cut down to supply the demand for newspapers and cheap
printings.
The manufacture of news calls for considerable skill and able
management, owing to the keen competition amongst the paper mills
devoted to this class of paper. The process as carried on in England is
as follows:--
The mechanical pulp, reaching the mill in the form of thick sheets
suitably packed up into bales, is first broken up again into moist
pulp. Various machines are used for this, such as Wurster's kneading
engine, Cornett's breaker, or some similar contrivance. An old potcher,
such as is used for the breaking and washing of rags, makes a good pulp
disintegrator. The broken pulp is discharged into beating engines in
any suitable or convenient manner and the right proportion of chemical
wood pulp added in the form of dry sheets. The beating process only
occupies thirty to forty minutes in the case of the common news, a
marked contrast to the eight or nine hours required by rags. China clay
is added to the contents of the beater, ten to twelve per cent. being
the general practice. This is followed by a measured quantity of rosin
size, and after thorough incorporation the size is precipitated upon
the fibres by means of alum.
In the commoner qualities of these papers the materials are added in
the dry state, but for finer grades of newspaper the china clay is
mixed with water, and carefully drained through a fine sieve before
use. The alum cake is also dissolved and treated in a similar manner in
order to keep out dirt and coarse particles likely to produce holes in
the paper.
The paper machine used for the manufacture of cheap printings is
constructed to produce as much as 100 to 180 tons of finished paper per
week, every detail being arranged for a large output at a very high
speed. In the modern machine it is possible to produce paper at the
rate of 450 to 550 feet per minute, the width of the sheet being from
120 to 160 inches.
Careful attention is paid to economy of every kind with regard to the
power required for driving the machine, the amount of steam consumed
in drying the paper, recovery of excess of fibre and china clay which
escapes from the machine wire, and similar details of a mechanical
order.
[Illustration: FIG. 37.--The Screens for removing Coarse Fibres from
Beaten Pulp.]
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