Improvements in Apparatus, for Straining Pulp for Paper Making
Year: 1897

page_text: Date of Application, 20th July, 1897--Accepted, 11th Dec., 1897
COMPLETE SPECIFICATION.
"Improvements in Apparatus, for Straining Pulp for Paper Making.”
I, SILVIO DE PRETTO, of Schio, Prov. of Vicenza, Italy, Engineer, do hereby declare
the nature of this invention, and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
This invention relates to improvements in apparatus for straining pulp for paper
making and has for its object to effect the same automatically in a more perfect
manner than heretofore has been the case, to facilitate the cleaning of the said
apparatus and obviate the frequent stoppages which can not be avoided by other
systems.
And in order that my invention may be more fully understood I have caused to be
appended hereunto one sheet of drawings marked with letters of reference indicating
like parts in the various figures.
Fig. 1 is a plan partly in section showing the zig-zag or return screw and some of
the plates removed. Fig. 2 is a longitudinal section, Fig. 3 an end view partly in
section and Fig. 4 a cross section of my improved apparatus for straining pulp.
To this end my invention' consists principally in having a series of rectangular vats A,
B, C, D, each one being supplied independently through the passage a made in
the wall S¹ of the reservoir. Each vat has a false bottom or partition, which is formed
by means of a plate b, usually made of bronze, having slits, the size of which varies
according to the quality of paper required to be made. In the bottom of each vat is
an opening which may be elliptical, circular or of any other shape, the said opening
being formed with an inner flange and is partly closed by a disc c in size smaller than
the corresponding opening and hermetically closed by placing an annular membrane
of rubber or of any other suitable material on top of the disc c and the inner_edge
being secured to the disc c whilst the outer edge is secured to the face of the flange
of the opening, the space between the periphery of the disc c and the periphery of the
said opening allows the membrane to bend.
The discs c receive a rapid vibratory movement from an eccentric shaft e, or
eccentric, and connecting rods d, the connection being made without joints by means
of a rod made of wood or of thin steel or of any other suitable flexible material which
allows for the oscillating movement. The discs c are guided vertically on each side
of the rods d by means of studs sliding in brackets attached to the frame of the
apparatus, which keep the discs c in a horizontal position during its vertical
movement. These guiding studs are provided with spiral springs.
The automatic removal of the waste material is effected by the following
arrangement-
A cylinder f reaching from end to end of the apparatus is furnished with brushes f¹
all round and having a to and fro and rotary movement, by this double movement
the removal of the waste material from the plates b is effected.

page_text: The ends g. g of the cylinder f are mounted in bearings h, h, the latter being
arranged to slide on tubes k, k. In the interior of the latter are the zig-zag or
return screws having their bearing at each of the said tubes and are rotated
simultaneously by bevel wheels, fixed on the shaft m and pulleys n, n¹, or by any
other suitable mechanism.
Each tube has a longitudinal slot in which slides a steel fork, the stem of which
is pivoted to the under side of the bearing h whilst the two members of the said fork
pass through the slot of the tube and fit into the threads of the said zig-zag or
return screw. The brushes are moved to and fro by means of the said fork
establishing communication between the said zig-zag or return screws and the
bearings h carrying the ends g of the cylinder f. The said brushes are arranged in
oblique fashion around the cylinder and may be formed of bristles. or rubber strips f¹,
there being four to. each vat.
The brushes f¹ are a fourth of the width of the plates b, the latter being cleaned
their whole width when the cylinder f has completed one revolution.
The brushes during their return do not revolve but at the end of each course they
turn of their circumference which may be effected by any well known mechanism.
Consequently during the forward traverse one of the brushes f¹ is in its normal
position in each vat (see Fig. 4), and in contact with the plates b thus removing the
waste material deposited on the said plates..
In returning the cylinder is turned which presents the brushes in oblique
fashion, see Fig. 3, and therefore do not come in contact with the plates.
At the end of the return traverse of the brushes the cylinder is again turned which
causes another brush to be placed in contact with the plate, the same action is
repeated on the next traverse.
The pulp is distributed into each vat by means of the passages a and drawn through
the slits of the plates by suction produced by the displacement of the discs c and
passes into the conduit p and receiver channel ready to be received by the
machine.
The waste material removed by the brushes is received by the channels from where
it can be discharged from time to time.
The mechanism shown in Figs. 3 & 4 consists of a ratchet wheel u fixed to the
axis of one end of the cylinder f. This wheel rotates with the cylinder and moves
with it backwards and forwards, the pawl u¹ acting upon the teeth of the ratchet
wheel always in one direction. There are also two projections v, v employed, v of
which meets with the stud u² on the disc w at the other end of the cylinder axis g at
the end of the travel of the cylinder f from the right to the left thus turning the
disc w and the cylinder f round until the stud u² free's itself from the projection v.
This partial rotation corresponds to of the circumference of the cylinder f. The
latter then runs from left to right and at the end of its travel the stud 8 which also
rotates of the circumference meets the projection which causes the disc w and
cylinder to revolve another of its circumference always in the same direction,
which movement is repeated.
Having now particularly described and ascertained the nature of my said Invention
and in what manner the same is to be performed, I declare that what I claim, is―
1st. In an apparatus for straining pulp for paper making, a. series of
vats A, B, C, D, each having a false bottom or partition b by means of which an
independent compartment is formed each having its own outlet for the purpose of
facilitating the cleaning or repairing without stopping the apparatus, substantially as
set forth.
2nd. In an apparatus as specified in the preceding claim, the employment of an
eccentric shaft e, or. eccentrics, and flexible connecting rods d by means of which
motion is imparted to the suction discs c, substantially as and for the purpose set
forth.
3rd. In an apparatus as specified in the preceding claims, the employment of

page_text: traversing and intermittently rotating brushes adapted to remove the waste
material from the plates b, substantially as set forth.
Dated this 19th. day of July, 1897.
F. BOSSHARDT & Co.
4, Corporation Street, Manchester. Agents to Applicant.