Chicago eagle. [volume] (Chicago, Ill.) 1889-19??, 1904-02-20

MANUFACTURE OF PAPER.
Modern Devices Have Com pictciy
kevo1utioniz cd the Work.

Modern Devices Have Com picteiy
kevoiutionizcd the Work.
. Improved methods In machinery and
the great change in the character OF
materials used has had an Important
bearing upon the printing art. iays the
Scientific American. In the earliest
mills established in this country, the
raw fiber, after being prepared In the
beating machine, was formed Into a
sheet In mold or wire sieve which
was dipped from the pulp vat by hQnd,
the water drained of and the pulp
left in a wet sheet in the mold. The
sheets so made were turned out upon,
felt press and then dried by exposing
to the air in single sheets. Such mills
were small and their output limited.
Strictly hand made paper today Is q
rarity, although 1t exists.
BY the aid Of the Fourdrlnier ma.
chine the transformation Of the fluid
to stock or finished paper Is made mi
automatic operation. The pulp IL
screened from the vat over an apron
to a moving endless wire cloth made Of
closely woven fine brass wire and sup
ported 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 main.
tanned and by preserving an unvarylng
flow of the pulp and constant for
ward motion of the wire cloth, the
thickness Of the layer Of pulp deposited
Is 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, leaving the fiber on the mesh
es. This first drying Is usually hasten
cd by various devices and the moist
web Is carried between rolls which are
covered with wooden felt and then
taken from the wire cloth on endless
WOODEN felts which pass 1t between
rolls and then to driers. These are
large metal cylinders heated by steam.
The paper has now acquired consider.
able strength. The water has been
evaporated and the heated cylinders
complete the drying process. The pa
per Is then given smooth surface by
the calender rolls. which are smooth
faced, heavy metal rollers. Finally the
finished paper Is reeled of In rolls and
cut into sheets Of the desired size. A
large paper mill will make $50 tons
Of finished paper day. The most
modern machinery turns out contin.
uous web Of finished paper ut the rate
Of 500 feet a minute. The raw ma.
terial Of wood pulp Is spruce, poplar
and In smaller quantities various other
woods arc employed. Wood pulp has
to q great extent superseded the use
Of rags and entirely 30 In the manufac.
ture Of news paper. Tho blocks Of
wood are pressed ALPHABETICALLY against
the edge Of a rapidly revolving grind.
stone and by attrltion reduced to q
mushy consistency.
There Is also chemical process OF
making wood pulp which Ia largely
used. The merchantable shape Of the
fiber differs somewhat. Ground wood
pulp Is ordinarily sold In folded sheets
only partially dry. and IN, therefore
under common conditions, only suitable
for use near the locality Of Its manu-
facture, its weight being 30 increased
by the water rs to preclude the profit
able transportation Of such lOw-pricet
product There are 703 paper making
plants in the United States and thu
total capital Is $187 .5O7, 7l3, giving EN-
ployment to "a, 1888 persons. The tota
cost Of the materials used was SO,
$780, 38 in 1900. The total value of tn,
products was 1927 1920, 1872 and the tota
power required for running the plants
was 764, S47-horse power.