Improvements in Paper Pulp Screens.
Year: 1887

page_text: Date of Application, 15th Mar., 1887.
Specification Accepted, 15th Apr., 1887.
COMPLETE SPECIFICATION.
Improvements in Paper Pulp Screens.
We, CALVIN RUSSELL and PATRICK HENRY CRAGIN, of Penn Yan, in the County
of Yates and State of New York, United States of America, Manufacturers, do hereby
declare the nature of our invention for IMPROVEMENTS IN PAPER PULP SCREENS and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
The invention consists in an improved construction and combination of parts
whereby the apparatus is rendered more efficient in its operation, and other important
advantages are attained for the same as hereinafter more fully explained.
In the annexed drawing, Fig. 1 is a side elevation of our improved paper pulp
screen with a portion of the internal arrangement thereof: Fig. is a longitudinal
vertical section of the same; Fig. 3 is a partial view of the opposite side of the pulp
vai; Fig. 4 is a top plan view of a paper pulp screen embodying that portion of our
invention relating to the pumping apparatus in the pulp vat underneath the screen;
Fig. 5 is a vertical longitudinal section of the same, and Fig. 6 is a vertical transverse
section through the side portion of the vat and screen.
V represents the pulp vat in which the impurities are eliminated from the paper
pulp, said vat being provided at its discharge end with a dam D which retains a body
of the liquid in the vat reaching nearly to the screen C, but at such a point
underneath it as to form an air space between the top of the pulp and underside of the
screen.
The screen has heretofore been firmly attached to the interior of the vat, and it was
therefore exceedingly difficult to obtain access to the pumping apparatus underneath
the screen when necessary for cleaning or repairs. To obviate this defect we now
make the screen removable from the vat by hinging to the top of the vai a frame F
which is closely fitted to the interior of the vat and adapted to be swung on its hinges
and raised out of the vat as represented by dotted lines in Fig. 1 and to said frame we
attach the screen C.
A A represent the oscillatory or rocking pumping bars which are submerged in the
diluted pulp underneath the screen. By securing to the top of the pumping bars one
or more longitudinal ribs, rr the bars are rendered more effective in their operation.

page_text: BB represent the stationary bars or partitions between the pumping bars A A.
These partitions we provide with longitudinal indentations or channels c in their tops,
and secure to the underside of the screen C strips d of wood metal or other suitable
material coinciding with the channels of the partitions, and fitted closely thereto so as
to form a tight joint and support the central portion of the screen, and they form a
separate and distinct compartment for each pumping bar.
To dispense with the stuffing boxes in the sides of the vat for the reception of the
journals of the pumping bars, we provide one side of the vat with openings o o
respectively at the ends of the pumping bars and detachably secure to the vat covering
plate which close said openings, and on their inner sides with suitable bearings for
the trunnions of the shafts of the pumping bars as shown in Fig. 2 of the drawing.
The opposite side of the vat we provide with port p and secure to the exterior of the
vat below said ports an apron L which rises to an elevation above the water line of the
vat.
The shafts a of the pumping bars we extend through the ports and terminate them
in crank arms which extend over the top of the apron and down on the exterior
thereof and are pivoted thereon at points respectively in lines with the shafts a.
A reciprocating rod R connected to the respective crank-arms, imparts the requisite
oscillatory motion to the pumping bars.
The pumping bars A A agitate the pulp and the air between the pulp and screen in
such a manner as to alternately force air upward through the screen and a suction
down through the same and thereby facilitates the operation of screening the pulp.
By practical tests we have found the efficiency of the pumping apparatus is
increased and the operation of the same facilitated by forming the pumping bars
wider than they have heretofore been made and by pivoting them at the center of
the top as shown on the second sheet of drawings.
The top of the pumping bar is inclined from the pivoted or longitudinal central line
toward opposite sides as shown at bb in Fig. 5, and the longitudinal side edges ee of
the top of the bar we curve upward as shown in the same figure.
Between the underside of the screen and top of the pumping bar we interpose a
barrier or strap d as shown in Fig. 5 extending along the longitudinal central line
of the bar and preferably secured to the underside of the screen said barrier serving
to arrest the flow of pulp across the top of the bar alternately toward opposite sides
during the rocking motion of the bar. We have discovered that without the barrier
the pulp is apt to flow across the top of the bar without producing the desired
At opposite
pumping action along the longitudinal central line of the rocking bar.
sides of the center of the pumping bar we secure to the top thereof the upward
projecting ribs heretofore referred to which, in conjunction with the upwardly curved
side edges of the bar and with the barrier d interposed between said ribs materially
increase the efficiency of the pumping bar. In this construction the inclination of the
central portion of the top of the bar toward opposite sides compensates for the reduction
of the motion of said portion of the pumping bar. By widening the pumping bars
we employ a smaller number of cranks and less motion of the cranks than is required
for the same size of screen by the pumping apparatus heretofore constructed.
Having now particularly described and ascertained the nature of our said invention
and in what manner the same is to be performed we declare that what we claim is :-
1. In combination with the paper pulp screen, a series of pulp compartments
separated from each other by intervening partitions extending to the underside of
the screen, and a series of pumping bars or plungers arranged respectively in the
said compartments, substantially as set forth.
2. In combination with the vat and screen, the oscillatory pumping bars A A
provided with the longitudinal rib or ribs substantially as described and shown.
3. In combination with the screen, subjacent pulp-vat and rocking pumping bars
in said vat, a barrier projecting from the underside of the screen toward the top of the
pumping bar to check the flow of pulp across the top of the pumping bar as se
forth.

page_text: 4. In combination with the screen and subjacent pulp-vat the pumping bar having
its top inclining from the longitudinal central line toward opposite sides, substantially
as described and shown.
5. In combination with the screen and subjacent pulp-vat, the pumping bar having
its top inclining from the longitudinal central line toward opposite sides, and the
longitudinal side edges of the top curved upward, substantially described and shown.
6. In combination with the screen and subjacent pulp-vat the pumping bar having
its top inclining from the longitudinal central line toward opposite sides, and the
longitudinal side edges of the top curved upward, and ribs projecting from the top of
the pumping bar substantially as described and shown.
7. In combination with the screen and subjacent pulp-vat, the pumping bar pivoted
at the center of its top and having the top inclining from the longitudinal central line
toward opposite sides of the bar, and the longitudinal side edges of the top of the
pumping bar curved upward, a barrier interposed between the screen and pumping
bar along the longitudinal central line of the top of the latter, and ribs projecting
from the top of the bar all constructed and combined, substantially as described and
shown.
8. The combination with the vat, screen and plungers in the vat, of partitions
arranged between said plungers and provided with indentations on their tops, and
strips secured to the underside of the screen and adapted to rest in the said
indentation and support the central portion of the screen in the vat substantially as
set forth and shown.
9. In combination with the screen C and pumping bars A A the vat N provided with
poris p, the apron L secured to the exterior of the vat below the ports thereof and
extending above the water line of the vat, and the crank arms bb extending through
the ports and up over the top of the apron and pivoted to the exterior thereof,
substantially as described and shown.
10. The combination with the vat V, of the pulp screen hinged on said vat as
set forth.
11. The pumping bars provided with a trunnion on one end in combination
with the vat provided with openings at said ends of the bars, and covering plates
detachably secured in said openings and provided with bearings for the trunnions of
the pumping bars, substantially as described and shown.
Dubad Tanya 15tLL. 1007