Scientific American Supplement, No. 363, December 16, 1882Various
Science
Scientific American Supplement, No. 363, December 16, 1882
Various
Science -- Periodicals
After the final beating, the mixture descends into a large reservoir
called the "stuff chest," whence it is pumped to the paper machine. The
pulp is of the consistency of milk when it pours from the spout of
the pumps on the paper machine. The latter is a complicated series of
rollers, belts, sieves, blankets, pumps, and gears, one hundred feet
long. To describe it or to understand a description of it would require
the vocabulary and the knowledge of a scientist. The milky pulp first
passes over a belt of fine wire cloth, through which the water partly
drains. It is ingeniously made to glide over two perforated iron plates,
under which pumps are constantly sucking. You can plainly see the broad
sheet of pulp lose its water and gain thickness as it goes over these
plates. Broad, blanket-like belts of felt take it and carry it over and
between large rolling cylinders filled with hot steam. These dry and
harden it into a sheet which will support itself; and without the aid of
blankets it winds among iron rolls, called calenders, which squeeze it
and give it surface. It is wound upon revolving reels at the end of the
machine.
If a better surface or gloss is required, it is carried to the super
calendering mill, where it is steamed and subjected to a long and
circuitous journey up and down tall stands of calenders upon calenders.
The paper is cut by machines having long, winding knives which revolve
slowly and cut, on the scissors principle--no two points of the blade
bearing on the paper with equal pressure at once. Girls pack the sheets
on the tables as they fall from the cutters, and throw out the damaged
or dirtied sheets. A small black spot or hole or imperfection of any
sort is sufficient to reject a sheet. In some orders fifty per cent. of
the sheets are thrown out. There is no waste, as the damaged paper is
ground into pulp again. Having been cut, the paper must be counted and
folded. Then it is packed into bundles for shipment. The young lady who
does the counting and folding is the wonder of the mill. Giving the
sheets a twist with one hand so as to spread open the edges, she gallops
the fingers of the other hand among them; and as quickly as you or I
could count three, she counts twenty-four and folds the quire. She takes
four sheets with a finger and goes her whole hand and one finger more;
thus she gets twenty-four sheets. Long practice is required to do the
counting rapidly and accurately. Twenty-four sheets, no more and no
less, are always found in her quires.
Papers of different grades are made of different stock, but by the same
process. Some paper stock is used. This must be bleached in lime and
soda ash. There are powerful steam engines in the mills for use when
the water is low. There are large furnaces and boilers which supply the
steam used in the processes.
Public-domain text, read in full here on John Shaqi.
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