Evening star. [volume] (Washington, D.C.) 1854-1972, 1903-12-09
PAPER AND PAPER PULP.
Change in Character Of Materials and
Machinery.

From the Scientific American.
Improved methods in machinery and the
great change in the character of materials
used has had an important bearing upon
the printing art. In the earliest mills es-
tablished in this country, the raw fiber
after being prepared in the beating ma
chine, was formed into sheet in a mold
or wire sieve which was dipped from the
pulp vat by hand, the water drained Off
and the pulp left in a wet sheet in the
mold. The sheets so made were turned out
upon a felt press and then dried by expos
ing to the air in single sheets. Such mills
We're small and the output was limited.
Strictly handmade paper today is a rarity
although it exists. By the aid of the Four
drinier machine the transformation of the
fluid to stock or finished paper Is made an
automatic operation. The pulp is screened
from the vat over an apron to a moving
endless wire cloth made of closely woven
fine brass wire, and supported by series
of small metal rolls set close together, yet
without touching each other.
In this way an even surface of the wire
cloth Is maintained and by preserving an
unvarying flow of the pulp and constant
forward motion of the wire cloth, the
thickness of the layer of pulp deposited was
kept uniform. BY lateral motion of the
supporting rolls the fibers are caused to
interlace in various directions and give
greater transverse strength to the texture
AS the pulp is carried along on the wire
cloth, much of the water drains through,
drying Is usually FASTENED by various de-
vices, and the moist web is carried between
rolls which are covered with wooden felt,
and then taken from the wire cloth on end
less wooden felts which pass it between
rolls and then to dryers. These are large
metal cylinders heated by steam. The pa
per has now acquired considerable strength
The water has been evaporated and the
heated cylinders complete the drying pro-
cess. The paper is then given a smooth
surface by the calender rolls, which are
smooth-faced, heavy metal rollers. Finally
cut into sheets of the desired size. large
paper mill will make $50 tons of finished
paper a day. The most modern machinery
turns out continuous web of finished pa
per at the rate of 500 feet a minute The
raw material of wood pulp is spruce. pop
lar, and In smaller quantities various other
woods are employed Wood pulp has to a
great extent superseded the use of rags
and entirely so in the manufacture Of news
paper. The blocks of wood are pressed
automatically against the edge of rapidly
revolving grindstone, and by attrition re-
duced to mushy consistency.
There is also a chemical process of max
ing wood pulp which is largely used. The
merchantable shape of the fiber differs
somewhat. Ground wood pulp is ordinarily
sold in folded sheets only partially dry and
is, therefore. under common conditions
only suitable for use near the locality of its
manufacture. its weight being so increased
by the water as to preclude the profitable
transportation of such a low-priced prod
uct. There are 763 paper-maling plants in
the United States. and the total capital is
$167 .507 .713. giving employment to 81 1856
persons The total cost of the materials
used was S70530, 2s6, in 1900. The total
value of the products was $127, 326, 182, and
the total power required for running the
plants was 764. 847 horsepower.