IMPROVEMENTS IN PAPER PULP ENGINES
Year: 1873

page_text: LETTERS PATENT to Frederick Curtis, of Boston, in the County of
Suffolk, and State of Massachusetts, of the United States of
America, for the Invention of "IMPROVEMENTS IN PAPER PULP ENGINES."
-A communication by Simeon Latham Gould,- resident of Skow-
hegan, in the County of Somerset, and State of Maine, United States
of America.
COMPLETE SPECIFICATION filed by the said Frederick Curtis at
the Office of the Commissioners of Patents, with his Petition
and Declaration, on the 3rd March 1873, pursuant to the 9t
Section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK
CURTIS, of Boston, in the County of Suffolk, and State of Massachusetts,
of the United States of America, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
PAPER PULP ENGINES," and have petitioned Her most Excellent Majesty
Queen Victoria, to grant unto me, my executors, administrators, and

page_text: assigns, Her Royal Letters Patent for the same, and have made solemn
Declaration that the same has been communicated to me by Simeon
Latham Gould, of Skowhegan, in the County of Somerset, and State of
Maine, of the United States of America.
NOW KNOW YE, that I, the said Frederick Curtis, do hereby
declare the nature of the said Invention to be as follows, referenco being
had to the Drawings accompanying this explanation, and in which the
Invention is shown in a vertical central section through the machine in
Figure 1, while Figure 2 is a horizental section through the same.
This Invention relates to machinery for making paper pulp. It
principally consists in a mode of maintaining the circulation of the stock
within the case or tub, or curb, and between the grinding surfaces by
centrifugal action induced by a rotary grinding disk, through the center
of which or thereabout the stock passes to and between the grinding
surface. It further consists in an improvement in the construction of
the caso, whereby the stock when thrown outward from between the
grinding surfaces by the centrifugal action of the rotary grinding disk,
will be effectually caused to return and be delivered into the central
opening or openings in said disk, whence it will again be circulated
between the grinding surfaces by the centrifugal action.
Within a case, tub, or curb A, provided at or near its bottom with a
suitable horizontal grinding bed C armed with blades a, is a disk or
wheel B fixed to a vertical shaft D supported on a step e, and having its
upper bearing in an arch G fast to the top of the curb or case; the
under surface of the disk, or that surface contiguous to the grinding
bed C, is armed with blades a thickly set and arranged, so as to operate
with a shear cut on the blades of bed O for reducing, disintegrating,
and separating the fibers of straw, wood, rags, and other substances for
making paper pulp, the object being to obtain two disintegrating or
grinding surfaces, between which the substance to be pulped must pass.
The Drawing does not show means for rotating the shaft D or for
adjusting this shaft up and down, as such means are well known to those
skilled in the art to which these improvements pertain, and need not
therefore be here particularized.
In the rotary disk B at or near its center I form one or more
openings 6 through which the stock will pass down to the bed C, where

page_text: it will be carried through between the grinding surfaces, and finally
thrown out from them by the centrifugal action induced by the rotary
grinding disk; I thus provide for circulation of the stock within the
curb or case and between the grinding surfaces; the stock after passing
from the center to the circumference of the disk between the grinding
surfaces, being then thrown off and gradually carried back over the top
of the disk until it falls again through the opening or openings 6, to be
again carried between the grinding surfaces and discharge at the
circumference from under the disk.
In order to better direct the stock back to the center of the disk B
after it has been throw off from between the grinding surfaces by
centrifugal action, I in some instances prefer to shape the case or curb
▲ as shown in the Drawing. It will be seen that its sides are bulging
and they terminate above in a curved overhanging contracted portion g,
the form of which is such as to turn and direct downward toward the
center of the case the substances which rise in contact with its bulging
sides; the general shape of the case below the concave contracted
portion is preferably that of a hyperboloid, which I believe to, be the
best adapted for directing upwardly the substances which are thrown
against its interior surface by the centrifugal action of the disintegrating
disk B; I do not however confine myself to the hyperboloidal shape,
as other forms approaching thereto may be adopted. At suitable
intervals inside of the case A. I arrange vertically four or more or less
partitions p, which will resist the tendency of the substances to be
carried around with the wheel B after they are thrown off therefrom.
I order that I may effect the working of the stock previous to
beating, and thus adapt my engine to both washing and beating or
grinding, I combine with the tub A a circular screen H composed of
woven wire, cloth, or other suitable material, and I dispose this screen
over the mouth of the tub and surrounding the shaft D, as shown in
Figure 1 of the Drawings, the center of the screen being formed with
a trumpet or tunnel mouth I, of a diameter considerably larger than
that of the shaft, and through which the water used in washing is to be
introduced from a suitable source to the tub below.
The "washer" or screen H is to be raised and lowered by upright
screws J, J, attached to it and screwing through the arch G, or operated
in any suitable manner, and when "washing" of the stock is to be done