Improvements in and relating to Strainers for Treating Paper Pulp, Separating Fibrous Materials from Starch, and like Purposes.
Year: 1896

page_text: Date of Application, 29th Feb., 1890
Complete Specification Left, 28th Nov., 1896-Accepted, 9th Jan., 1997.
Date of Application, 29th ed., 10
Complete Specification Left, 28th Nov., 1896-Accepted, 9th Jan., 1897.
PROVISIONAL SPECIFICATION.
Improvements in and relating to Strainers for Treating Paper
Pulp, Separating Fibrous Materials from Starch, and like
Purposes.
I, DAVID NOBLE BERTRAM, of St. Katherines Works, Sciennes in the City and
County of Edinburgh, Engineer, do hereby declare the nature of my invention to
be as follows:-
This invention relates to improvements in strainers for treating pulp for paper
making or like purposes, or separating fibrous materials from starch and the like,
and consists of a cast iron vat, circular in form, oval, oblong, or square, but pre-
ferably circular, with shelf formed therein, to which the strainer plates are fixed at
their outer edges, and supported by, and fixed to in centre, the Hange of the pipe
which admits the pulp into the strainer. The means adopted for fixing the plates
may be of the usual style, but preferably by a dovetailed ring, fixed to the shelf
cast in vnt referred to above. The edge which comes in contact with the plates
will be dovetailed, and the back will be square, thus the ring forms a wedge, and
is drawn down by bolts, or pressed down from the top by hinge bolts or other
means. This ring may be fixed to an extent of less than half its diameter, so as
to cause less trouble in removing the strainer plate or plates.
The refuse channel round the entire diameter immediately inside of the vat
from its outer diameter is formed, into which the refuse matter is discharged as
explained hereafter.
Strainer plate or plates may be cast in one or more pieces, or made of rolled
brass, with strengthening ribs, but preferably cast in one piece, and whether in one
or more pieces, it or they may be flat, or made to form a concave or convex cone,
the pulp flowing on to the plates in either form as may be found more suitable.
These plates will be finished with drilled slots and slits formed as usual, and may
be resurfaced and reclosed in the ordinary manner. Periphery of this plate or
plates will be bevelled to suit the dovetail formed on the ring already referred to
as fixing in the plates. In centre a hole of sufficient diameter will be formed,
through which the pulp will flow on to the top of strainer plates.
The diaphragm plate will be circular in form, the plate being of cast iron, brass
or other material, jointed to the vat at outside by a circular strip of rubber, and
the usual brass or iron strips for connecting the rubber to the edge of vat and
diaphragm plate, and in like manner in the centre, which will connect the
diaphragm plate to the flange cast on pipe which admits the pulp into strainer.
This diaphragm will be placed immediately below, the strainer plates, and at a
proper distance therefrom.
The pulsating action will be conveyed to the diaphragm by the usual rotating
shaft, mounted with variable cranks, and placed below the diaphragm and fixed to
sole plate, or fixed to supports which carry the vat; or in place of variable cranks
the end of diaphragm shaft may be turned to give a fixed stroke to diaphragm, or
elliptical sleeves may be fixed on the end, and arranged so as, to give more or less
stroke, or the diaphragm may be actuated by cams, eccentrics, or in any convenient
way for giving the necessary pulsating motion to diaphragın.
The pulu is conveyed by a bine from the sand traps, passing along below the

page_text: diaphragm, and delivering the pulp on to the top side of strainer plate or plates.
With the pressure accruing from the usual head of pulp, between the level of
strainer plates and pulp in eand traps, such pulp will rise above the mouth of the
orifice, and thereby cause a current towards the periphery of the strainer plates,
which will tend to carry the refuse matter with it to the auxiliary channel. Such
inlet of pulp may be arranged so that the pulp will be delivered directly on the
top of the strainer plates by shute or pipe, and if preferred it can be conveyed
in a shute the full width of the diameter of plates. Instead of the pulp however
being so delivered on to the strainer plates, it may be allowed to flow on to the
plates from a channel formed round the vat immediately inside of periphery, which
would be practically the same shape and in the same position as refuse channel
already referred to, in which case the refuse matter would be discharged through
a hole in centre of plates, or any other convenient part.
The combined plate washing movement and refuse discharging apparatus would
consist of an upright shaft, driven from the rotating diaphragm shaft by pulley,
worm, and worm wheel, the worm gear revolving in a case which may be filled
with oil and covered on top. This shaft will pass through pipe which convoys
the pulp to the strainer, with stuffing box at lower end, and on the top will be
mounted a crosshend to which one or more arms will be fixed, which will revolve
among the pulp, and so arranged that they can be set at a greater or lesser distance
from the face of the strainer plates.
These arms can be made of any light material, such as copper, brass, zinc or the
like and in form straight, tangential, radiating, or of a scroll shape, whichever will
best prevent the pulp from settling on the plates, and induce the travel of the rofuse
from the centre to the periphery of strainer plates, whence it is discharged into
the refuse channel. These arms will be made to revolve constantly at a suitable
speed, or intermittently. If intermittently, the motion preferably employed would
consist of two shafts instead of one for the constant revolving motion, and these
two shafts coupled up by spar or friction sector and pinion, the proportions being
suitable for the speed at which the arms require to revolve. The ends would be
made of a scoop shape, so as to slightly raise the pulp or refuse over a sunil ledge,
and in place of such arms being fixed to the crosshead, they may be made of other
shape to revolve among the pulp driven by spur or other gear.
The ledge for preventing too much pulp flowing into the refuse channel will be
formed on the top of ring which fixes strainer plates, the height of the ledge being
rather higher than the depth of the pulp, working on the strainer plates; the point
of arm which is fixed to crosshead already referred to heing of such a shape as to
discharge the refuse along with the usual amount of clean pulp over this ledge
into the refuse channel. Instead of the arm discharging the pulp over this ledge,
openings can be formed in it of suitable size, and number, to allow the refuse to
Bow into channel. These may be cut straight through, or slot formed on top of
ring. Further the ledge may be made deeper, and balance face valves arranged
to cover the openings formed in it, with an angled face, which will come in contact
with the revolving arm, and thus open the valve, the valve having a weight or
spring at back to close it immediately the contact has ceased.
A circular stop hoard may be employed to work automatically and at intervals.
This stop hoard would be of copper, zinc, or other like material, lying on the outer
edge of plates or on the ring which keeps the plates in position, and arranged with
a crosshend and arms, the intermittent motion being caused by cam or eccentric
below, the connection between such cam and eccentric being arranged by the shaft
which drives the revolving arms being made hollow, and a rod passing down
connected to the cam or eccentric, and fixed in the crosshead, from which stop
board is suspended.
Instead of any of the above arrangements, a circular ring may be used revolving
slowly round the edge of the plate. In this ring a small opening would be made,
which opening as it travels round the edge of the plate would allow the refuse
matter to be discharged all round the plates.

page_text: The discharge orifice for the clean pulp would be formed at any part of the vat,
passing below the refuse channel, and to the mouth of which the usual regulating
pulp box with valve would be applied.
The discharge cock for refuse from channel would be of the usual type, either
with key or sluice.
The driving gear will be of the usual type, fitted to rotating pulsating shaft, or
diaphragm, with fly wheel, bearings and other fittings; and the vat will be carried
on the usual supports and sole plate.
Dated 28th Februan 1906
W. R. M. THOMSON & Co.,
96 Buchanan Street, Glasgow, Agents.
Improvements in and relating to Strainers for Treating Paper
Pulp, Separating Fibrous Materials from Starch, and like
Purposes.
I, DAVID NOBLE BERTRAM of St. Katherines Works, Sciennes, in the City
and County of Edinburgh, Engineer, do hereby declare the nature of my invention,
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement in writing :-
This invention relates to improvements in strainers for treating pulp for
paper making or like purposes, or separating fibrous materials from starch and the
like.
And in order that my said invention and the manner of carrying same into
practice may be properly understood, I have hereunto appended a sheet of
explanatory drawings in which the same reference letters are used to indicate like
parts in the several figures where shown.
Figure 1 is a sectional elevation and Figure 2 a plan view of a circular shaped
strainer as constructed in accordance with my improvements, and Figure 3 is an
elevation at right angles to Figure 1.
Figure 4 is a sectional elevation to an enlarged scale of a detached portion of
the strainer vat.
Figures 5 and 6 are a detached sectional elevation and corresponding plan of
one of the strainer plates.
Figure 7 shows a detached elevation and plan of the crosshead to which the
revolving arms over strainer plates are attached and
Figure 8 is a detached view of a ring and valve which may be fitted beyond ring
at outer edge of strainer plates.
Referring to these drawings:-
The improvements consist of a cast iron vat A circular in form, oval, oblong,
or square but preferably circular, with shelf A formed therein, to which the
strainer plates B are supported and fixed at their outer edges, and supported by
and fixed to in centre the flange C of the pipe C which admits the pulp into the
strainer. The means adopted for fixing the plates B may be of the usual style,
but preferably by a dovetailed ring A' fixed to the shelf A¹ cast in vat A referred
to above. The edge which comes in contact with the plates B will be dovetailed,
and the back will be square thus the ring forms a wedge, and is drawn down by
bolts, or pressed down from the top by hinge bolts or other means. This ring A
may be fixed to an extent of less than half its diameter, so as to cause less trouble
in removing the strainer plate or plates B.
The refuse channel A round the entire diameter immediately inside of the vat A

page_text: from its outer diameter is formed, into which the refuse matter is discharged as
explained hereafter.
Strainer plate or plates B may be cast in one or more pieces, or made of rolled
brass, with strengthening ribs, but preferably cast in one piece, and whether in one
nr more pieces, it or they may be flat, or made to form a convex cone, the pulp
flowing on to the plates in either form as may be found more suitable. These
plates B will be finished with drilled slots and slits formed as usual, and may be
resurfaced and reclosed in the ordinary manner. The periphery B of this plate
or plates B will be bevelled to suit the dovetailed formed on the ring A
already referred to as fixing in the plates. In centre a hole of sufficient diameter
will be formed, through which the pulp will flow on to the top of strainer plates B.
The diaphragm plate D will be circular in form, the plate being of cast iron,
brass or other material, jointed to the underlung flange As of the vat A at outside
by a circular strip of rubber, and the usual brass or iron strips for connecting the
rubber to the edge of vat and diaphragm plate at D', and in like manner at D
in the centre, which will connect the diaphragm plate D to the flange C³ cast on
pipe C which admits the pulp into strainer B. This diaphragm D will be placed
immediately below the strainer plates B and at a proper distance therefrom,
The pulsating action will be conveyed to the diaphragm D by the usual rotating
shaft E mounted with variable cranks at E, and placed below the diaphragm and
fixed to sole plate or fixed to supports which carry the vat, or in place of variable
cranks the end of diaphragm shaft may be turned to give a fixed stroke to
diaphragm, or elliptical sleeves may be fixed on the end, and arranged so as to
give more or less stroke, or the diaphragm may be actunted by cams, eccentrics,
or in any convenient way for giving the necessary pulsating motion to diaphragm.
The pulp is conveyed by a pipe C from the usual sand traps, passing along
below the diaphragm D and delivering the pulp on to the top side of strainer plate
or plates B. With the pressure accruing from the usual head of pulp, between
the level of strainer plates 13 and pulp in sand traps such pulp will rise above the
mouth of the orifice, and thereby cause a current towards the periphery of the
strainer plates B which will tend to carry the refuse matter with it to the auxiliary
channel. Such inlet of pulp may be arranged so that the pulp will be delivered
directly on the top of the strainer plates B by shute or pipe, and if preferred
it can he conveyed in a shute the full width of the diameter of plates.
The combined plate washing movement and refuse discharging apparatus would
consist of an upright shaft driven from the rotating diaphragm shaft E by
pulley E and ordinary worm, and worm wheel, revolving in a case which inay
be filled with oil and covered on top. This shaft F will pass through pipe C
which conveys the pulp to the strainer, with stuffing box F at lower end, and on
the top will be mounted a crosshead F to which one or more arms will be
fixed, which will revolve among the pulp, and so arranged that they can be set at
a greater or lesser distance from the face of the strainer plates B. These arms F
can be made of any light material, such as copper, brass, zinc or the like, and in
form, straight, tangential, radiating, or of a scroll shape, whichever will best
prevent the pulp from settling on the plates B and induce the travel of the refuse
from the centre to the periphery of strainer plates, from whence it is discharged
into the refuse channel. These arms will be made to revolve constantly at a
suitable speed. The ends would be made of a scoop shape, so us to slightly raise
the pulp or refuse over a small ledge, and in place of such arins being fixed to
the crosshead F they may be made of other shape to revolve among the pulp,
driven by spur or other gear.
The ledge for preventing too much pulp flowing into the refuse channel A
will be formed over the top of ring A which fixes strainer plates B the height
of the ledge being rather higher than the depth of the pulp working on the strainer
plates; the point of arm which is fixed to crosshead F already referred to
being of such a shape as to discharge the refuse along with the usual amount of
clean pulp over this ledge into the refuse channel A.

page_text: Further as shown in Figure 8 a ring f may be placed outside of ring A and
balance face valves arranged to cover the openings formed in it, with a
projecting angled face f', which will come in contact with the revolving arin F.
and thus open the valve, the valve having a weight or spring at back to close it
immediately the contact has ceased.
A circular ring or stop board may be employed to work automatically and at
intervals. This ring would be of copper, zinc, or other like material, lying on the
outer edge of plates B, or on the ring A which keeps the plates in position, and
arranged with a crosshead and arms, and lifted at intervals like a valve to allow pulp.
to flow into channel A, the intermittent motion being caused by cam or eccentrie
below, the connection between such cam and eccentric being arranged by the shaft
which drives the revolving arms being made hollow, and a rod passing down
connected to the cam or eccentric, and fixed in the crosshead, from which the ring
is suspended.
The discharge orifice for the clean pulp would be formed at any part of the vat,
passing below the refuse channel, and to the mouth of which the usual regulating
pulp box with valve would be applied.
The discharge cock for refuse from channel would be of the usual type, either
with key or sluice.
The driving gear will be of the usual type, fitted to rotating pulsating shaft, or
diaphragin with fly wheel, bearings and other fittings; and the vat will be carried
in the usual supports and sole plate.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
First. In circular strainers the method of introducing the pulp from below by
a pipe in centre of strainer plate, substantially as herein described in reference to
and shown in the accompanying drawings.
Second. In circular strainers the combination of central inlet pipe with refuse
channel formed in vat, substantially as herein described in reference to and shown
in the accompanying drawings.
Third. In circular strainers the method of securing the plates consisting in
bevelling the inner and outer edges of same and having a bevelled recess in central
pipe and a bevelled ring at outer edge bearing against a square edge formed in
vat, the outer bevelled ring being screwed down to secure the plates, substantially
as herein described in reference to and shown in the accompanying drawings.
Fourth. The combination of a circular strainer with the scroll shaped arms for
assisting the flow of pulp and refuse to outer edge and the gearing for actuating
same substantially as herein described in reference to and shown in the accompanying
drawings.
Fifth. The combination of a circular strainer with the ring at outer edge of
plate fitted with valves which are actuated by the scroll arms, substantially as
berein described in reference to and shown in the accompanying drawings.
Sixth. The general arrangement of parts of strainer and gearing for the
purposes described and illustrated in the accompanying drawings.
Dated the 27th day of November 1896.
W. R. M. THOMSON & Co.,
96 Buchanan Street, Glasgow, Agents..