Improvements in Pulp Strainers.
Year: 1896

page_text: Improvements in Pulp Strainers.
I, JOHN WHITE, of the Firm of James Bertram and Son, (Limited), Leith
Walk Foundry, in the City of Edinburgh, Engineer, do hereby declare the nature
of this invention to he as follows:-
This invention which relates to apparatus for straining paper pulp comprises an
improved strainer of the type in which the vat wherein the straining operation
takes place is caused to rock or oscillate, but of novel arrangement and design, as
also several improvements in details applicable both to that and to other types of
strainers.
In the improved strainer the vat or trough is mounted to rock or oscillate on
trunnion or other bearings on a sole plate below and the usual pulsating disc or
diaphragm is operated either directly from a crank shaft whose axis is coincident
with the axis of oscillation or through connecting rods jointed in the line of said
axis.
The strainer plates are preferably divided into two equal portious in the cross
section of the strainer by means of a longitudinal bar either cast with the vat or
made as a separate piece and secured to the ends of the vat this bar being adapted
to support the plates; but the plates may be cast in one length in the cross section
of the strainer and be similarly supported by a bar running the full length of the
strainer.
The disc or diaphragm is formed with a recess or recesses inclining preferably
towards one end or towards the centre and terminating in a pocket for catching
the fine dirt which passes through the plates with the pulp, a valve being provided
for periodically drawing off the deposit. The weight of the disc and of the
connecting rod by means of which it is operated from the crank shaft is carried by
a helical or other spring interposed between the disc and an adjustable cross bar -
which latter may form a guide for the vertical movement of the disc. The
pulsating disc may be operated in the usual way by two cranks and connecting
rods, but it is preferably operated by a single connecting rod forked at its upper
end to engage the disc at two points and having its lower end connected to a single
adjustable crank pin at the end of the crank shaft.
The crank pin and main bearing of this shaft are enclosed within an oil box over
the sole plate to ensure that the bearings will have constant lubrication and to
exclude water. The connecting rod passes up through an opening in the .top of
the oil box, a domed or umbrella piece being attached to the rod and extending
over the opening to prevent water getting in. The crank shaft is carried through
a stuffing box in the side of the oil box. The main bearing bushes are held in
position by means of a screw bolt whose end bears on the cover of the bearing.
block and which is screwed through a stirrup or clip adapted to engage snugs on
the block. The bolt passes down through a clearing hole in the top of the oil box
a nut being provided and screwed down to close the hole. The head of the bolt
being outside the oil box it is always accessible for tightening the bearing bushes
without running off the oil and opening up the oil box. For the like reason the
nuts of the main bolts of the crank pin bearings are made to project through the
opening in the top of the oil box through which the connecting rod passes so that
they may be tightened or adjusted by removing the umbrella piece.

page_text: The outer end of the crank shaft may be supported by a bush in one of the
trunnion bearings on which the strainer vat oscillates, but an outside bearing is by
preference provided and is made self lubricating by forming within it an oil cavity
and providing means for carrying the lubricant to the journal bearings. A cover
plate is also provided to prevent access of water to the bearing. The trunnion is
placed outside or beyond the rat to leave space for the main driving pulley and for
a helt pulley from which movement is transmitted to the mechanism which imparts
the oscillating or rocking motion to the vat.
This movement is communicated to a crank shaft or cam or eccentric shaft and
connecting rod coupled thereto and to a stationary bracket by means of gearing
carried on the end of the oscillating vat and moving with it. This gearing
comprises a pulley driven from the belt pulley on the main crank shaft and carried
on a shaft extending through a stuffing box into an oil box encasing the gearing
and bearings of the shafts and bolted on the end of the vat. On this shaft is a
bevel wheel meshing with a similar wheel on a worm shaft having on it a worm in
gear with a worm wheel on the crank shaft which passes out through the oil box.
The crank shaft is furnished with an adjustable crank pin or in lieu thereof au
eccentric or cam may be provided to act on the end of the connecting rod whose
opposite end is coupled to the stationary bracket. The bracket also serves as a
support for a buffer spring or springs coupled to the vat by a rod having on it an
adjustable cap or caps by means of which the degree of compression on the spring
or springs may be regulated.
The delivery box, into which the pulp is discharged from the strainer in line
with the trunnion bearing on the side removed from the driving gear, is connected
to the strainer by a flanged rubber tube. secured at both ends by brass flanges or
like means. To provide for the discharge of any fine sand or other heavy matter
which may pass through the strainer plates, the delivery box is made with a false
or double bottom the upper one being provided with a valve which normally
remains open to permit of the passage and deposit of sedimentary matter into the
lower part, the valve being closed when it is desired to run off any sediment from
the bottom part while the strainer is at work.
To permit of altering the throw of the crank pin, which operates the pulsating
diaphragm, without removing the oil box, the shaft is made hollow and bored out
eccentrically at each end the intervening space being simply recessed. The dise
is bored with a taper the bore being concentric with that of the shaft. The crank
pin is on a dise fitted in the bore of the dise on the shaft, and on it is forged a
shank which is turned to fit the bored parts of the shaft and passes through the
latter, being screw threaded near its outer end and held in place by lock nuts.
The extreme end of the shank is made 'square or otherwise formed so that it may
be turned with a key and by turning it the crank pin may be brought to a position
in which it is concentric with the periphery of the shaft or more or less eccentric
to it, the amount of throw of the pin being indicated and regulated if desired by a
graduated scale marked on the end of the shaft and on a collar or washer fitted on
the shank inside the lock nuts.
When two crank pins are used, and it is desired to provide for altering the throw
of both, the shaft which may be of any length has two discs or plates forged or
keyed on it. The end crank pin is fixed in any of the usual ways, and may be
hollow or solid. The other crank pin which is in the length of the shaft is fixed to
a plate or disc on the shaft, but it is bored out to a larger diameter than the
diameter of the shaft. The difference between the diameter of the shaft and the
bore of the crank pin allows a sufficient amount of "throw" being given to
the crank pin without breaking the continuity of the shaft. This arrangement
allows two cranks to drive the pulsating diaphragin and one stuffing box is only
necessary for the shaft passing through the side of the oil box which encloses pins
and bearings as well as the length of shafting between the crank pins. One
bearing only may be provided in the length of the shaft between the crank pins, or
by boring out both crank pins the shaft may be extended out to provide for a

page_text: second bearing beyond the end pin. Or again the shaft may be extended beyond
the crank pin by putting another stuffing box and gland on the oil box.
The stuff led on to the strainer is fed into a central space or spaces between
sluice boards extending longitudinally the entire length or part of the length of the
vat, the sluices being fitted one on each side of the longitudinal bar which supports
the strainer plates and inclined thereto. They are fitted adjustably so that the
flow of the stuff may be regulated and distributed equally over the plates.. In this
arrangement a channel for the waste is provided on each side of the vat, and the
strainer is caused to rock or oscillate to an equal extent on each side of the axis.
When the strainer is designed to rock or oscillate only to one side of the axis so
that one side dips below and rises to the horizontal line the longitudinal bar which
supports the strainer plates is made to form a central waste channel dividing the
plates longitudinally and a waste channel is also formed along the dipping side of
the vat. In this case the stuff is fed in between adjustable sluices placed one in
proximity to the higher side of the vat and the other close to the longitudinal
dividing bar so that the pulp is suitably distributed over the plates of both
divisions of the strainer.
Instead of supporting the plates upon a longitudinal bar they may be carried
by a number of cross bridges dividing the vat transversely in which case the
stuff is fed on to the plates from a longitudinal channel on one side of the vat
and the waste is carried off by a channel on the opposite side. This form of
strainer may be oscillated or rocked equally to either side of its axis or only to
one side.
The strainer plates in any of the arrangements described may be held in place
on either side of the supporting bar by means of clips which bridge the bar or by
an inverted channel bar secured to the supporting bar by screw studs thereon and
outs or other fastenings above the clips or channel bar.
Overflow openings may be cast in the end of the vat nearest the delivery box
so that should the strainer get too full the stuff may run through the openings to
the spout leading to the auxiliary strainer.
Dated this 5th day of January 1896
WALLACE FAIRWEATHER,
Chartered Patent Agent,
62 St. Vincent Street, Glasgow, Agent for the Applicant.
1, JOHN WHITE, of the Firm of James Bertram and Son, (Limited), Leith
Walk Foundry, in the City of Edinburgh, 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 which relates to apparatus for straining paper pulp comprises an
improved strainer of the type in which the vat wherein the straining operation
takes place is caused to rock or oscillate, but of novel arrangement and design, as
also several improvements in details applicable both to that and to other types of
strainers.
The invention is illustrated by the accompanying drawings in which
Figure 1 is a longitudinal sectional elevation of one modification of the improved
pulp strainer, Figure 2 a sectional plan Figure 3 a transverse vertical section of
the same and Figure 1 a detail hereinafter referred to.
Figure 4 is a longitudinal sectional elevation, Figure a plan and Figure 6 a

page_text: transverse vertical section of a modihcation in construction of part of the
strainer.
Figure 7 is a transverse vertical section of a further modification, and
Figures 8, 9 and 10 are views of details hereinafter referred to.
In the improved strainer represented at Figures 1, 2 and 3, the vat or trough A
is mounted to rock or oscillate on trunnion or other bearings B, B' on a sole
plate C below and the usual pulsating disc or diaphragm Dis operated either
directly from a crank shaft E whose axis is coincident with the axis of oscillation
or through connecting rods jointed in the line of said axis; or the diaphragm may
be operated by a cam or tappet keyed on a shaft whose axis is coincident with the
axis of oscillation.
The strainer plates F are preferably divided into two equal portions in the cross
section of the strainer by means of a longitudinal bar G either cast with the vat
or made as a separate piece and secured to the ends of the rat, this bar G being
adapted to support the plates F; but the plates may be cast in one length in the
cross section of the strainer and be similarly supported by a bar running the full
length of the strainer.
The disc or diaphragm D is formed with a recess d or recesses inclining
preferably towards one end or towards the centre and terminating in a pocket for
catebing the fine dirt which passes through the plates F with the pulp, a valve
being provided for periodically drawing off the deposit. The weight of the disc
and of the connecting rod J by means of which it is operated from the crank
shaft E is carried by a helical or other spring H interposed between the disc and
an adjustable cross bar I which latter may have a pin i projecting from it and
entering a recess in the under side of the diaphragm D to form a guide for the
vertical movement of the disc the spring H being also surrounded by an oil cup
when desired. The pulsating dise may be operated in the usual way by two
cranks and connecting rods or by two cams or tappets but it is proferably operated
by a single connecting rod J forked at its upper end J' to engage the disc at two
points and having its lower end connected to a single adjustable crank pine at the
end of the crank shaft E.
The crank pine or cam or tappet and maiu bearing E¹ of this shaft E are
enclosed within an oil box K over the sole plate C to ensure that the bearings will
have constant lubrication and to exclude water. The connecting rod J passes up
through an opening k in the top of the oil box K, a domed or umbrella piece k
being attached to the rod and extending over the opening to prevent water getting
in. The crank shaft E is carried through a stuffing box K' in the side of the oil
box K. The main bearing bushes e' are held in position by means of a screw
bolt whose end bears on the cover of the bearing block E' and which is
screwed through a stirrup or clip adapted to engage snugs e on the block E'.
The bolt passes down through a clearing hole in the top of the oil box Ka
nut being provided and screwed down to close the hole. The head of the bolt k
being outside the oil box K it is always accessible for tightening the bearing
bushes without running off the oil and opening up the oil box. For the like
reason the nuts e of the main bolts of the crank pin bearings e are made to
project through the opening k in the top of the oil box K through which the
connecting rod J passes so that they may be tightened or adjusted by removing
the umbrella piece.
The outer end of the crank shaft E may be supported by a bush in one of the
trunnion bearings L on which the strainer vat oscillates, but an outside bearing E
is by preference provided as shown by Figure 14 and it is made self lubricating by
forming within it an oil cavity y and providing means for carrying the lubricant to
the journal bearings. A cover plate E may also be provided to prevent access of
water to the bearing. The trunnion B is placed outside or beyond the vat to
leave space for the main driving pulley M aud for a belt pulley N from which
movement is transmitted to the mechanism which imparts the oscillating or rocking
motion to the vat. This movement is communicated to a crank shaft or cam or

page_text: eccentric shaft and connecting rod P coupled thereto and to a stationary bracket Q
by means of gearing carried on the end of the oscillating vat and moving with it.
This gearing comprises a pulley N' driven from the belt pulley N on the main
crank shaft E and carried on a shaft N' extending through a stuffing box N into
an oil box N encasing the gearing and bearings of the shafts O, Pi and N' and
bolted on the end of the vat A. On this shaft N' is a bevel wheel p meshing with
a similar wheel pl on the worm shaft P.having on it a worm p' in gear with a
worin wheel on the crank shaft O which passes out through the oil box N.
The crank shaft O is furnished with an adjustable crank pin or in lieu thereof an
eccentric or cam may be provided to act on the end of the connecting rod whose
opposite end is coupled to the stationary bracket Q. The bracket also serves as a
support for a buffer spring Q' or springs coupled to the vat A by a rod R having
on it an adjustable cap R or caps by means of which the degree of compression
on the spring or springs may be regulated.
The delivery box S into which the pulp is discharged from the strainer in line
with the trunnion bearing L' on the side removed from the driving gear, is
connected to the strainer by a flanged rubber tube S secured at both ends by
brass flanges S or like means. To provide for the discharge of any fine sand or
other heavy matter which may pass through the strainer plates, the delivery box S
is made with a false or double bottom the upper one being provided with a valve S
which normally remains open to permit of the passage and deposit of sedimentary
matter into the lower part, the valve being closed when it is desired to run off any
sediment from the bottom part while the strainer is at work.
To permit of altering the throw of the crank pin e, which operates the pulsating
diaphragm, without removing the oil box K, the shaft E is made hollow as shown
at Figure 8 and bored out eccentrically at each end at the intervening space
being simply recessed. The disc is bored with a taper the bore being concentric
with that of the shaft E. The crank pine is on a disc e fitted in the bore of the
disc on the shaft E, and on it is forged a shank eo which is turned to fit the
bored part of the hollow shaft E and passes through the latter, being screw
threaded near its outer end at e" and held in place by lock nuts e". The extreme
end of the shauk is made square or otherwise formed so that it may be turned
with a key and by turning it the crank pin e may be brought to a position in which
it is concentric with the periphery of the shaft E or more or less eccentric to it,
the amount of throw of the pin e being indicated and regulated if desired by a
graduated scale marked on the end of the shaft and on a collar or washer fitted on.
the shank inside the lock nuts.
When, as indicated at Figure 9, two crank pins are used, and it is desired to
provide for altering the throw of both, the shait E which may be of any length
has two discs or plates e", es, forged or keyed on it. The end crank pine is
fixed in any of the usual ways, and may be hollow or solid. The other crank
pin which is in the length of the shaft is fixed to the plate or dise on the
shaft E, but it is bored out to a larger diameter than the diameter of the shaft E.
The difference between the diameter of the shaft and the bore of the crank
pin e allows a sufficient amount of "throw" being given to the crank pin
without breaking the continuity of the shaft. This arrangement allows two
cranks 'to drive the pulsating diaphragm D and one stuffing box is only necessary
for the shaft passing through the side of the oil box K which encloses pins and
bearings as well as the length of shafting between the crank pins e, el. One
bearing only may be provided as shown in the length of the shaft between the
crank pins, or by boring out both crank pins the shaft E may be extended
out to provide for a second bearing beyond the end pin e. Or again the shaft may
be extended beyond the crank pin by putting another stuffing box and gland on
the oil box K.
The stuff led on to the strainer is fed into a central space or spaces between
sluice-boards T extending longitudinally the entire length or part of the length
of the vat A, the sluices being fitted one on each side of the longitudinal bar G

page_text: which supports the strainer plates F and inclined thereto. They are fitted
adjustably so that the flow of the stuff may be regulated and distributed equally
over the plates. In this arrangement a channel A¹ for the waste is provided on
each side of the vat, and the strainer is caused to rock or oscillate to an equal
extent on each side of the axis L. When the strainer is designed to rock or
oscillate only to one side of the axis so that one side dips below and rises to the
horizontal line the longitudinal bar G which supports the strainer plates F is
made to form a central waste channel A dividing the plates longitudinally as
indicated at Figure 7, and a waste channel A is also formed along the dipping
side of the vat A. In this case the stuff is led in between adjustable sluices T, T₁,
placed one T in proximity to the higher side of the vat and the other T' close
to the longitudinal dividing bar so that the pulp is suitably distributed over the
plates of both divisions of the strainer.
Instead of supporting the plates upon the longitudinal bar they may be carried
by a number of cross bridges G dividing the vat transversely as shown by
Figures 4, 5 and 6 in which case the stuff is fed on to the plates from a longi
tudinal channel A' on one side of the vat and the waste is carried off by a
channel A on the opposite side. This form of strainer may be oscillated or
rocked equally to either side of its axis or only to one side.
The strainer plates in any of the arrangements described may be held in place
on either side of the supporting bar G by means of clips which bridge the bar or
by an inverted channel bar g' secured to the supporting bar G by screw studs g
thereon and nuts or other fastenings above the clips or channel bar g' as indicated.
at Figure 10.
Overflow openings may be cast in the end of the vat nearest the delivery box
so that should the strainer get too full the stuff may run through the openings to
the spout leading to the auxiliary strainer.
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:-
1. The combination of parts constituting the improved pulp strainer herein-
before described with reference to Figures 1, 2 and 3 of the accompanying
drawings.
2. In a pulp strainer a disc or diaphragm. formed as described with a depressed
recess and pocket and valve for catching and periodically removing the fine dirt
passing through the strainer plates.
3. In a pulp strainer the combination with the pulsating disc or diaphragm of
& spring interposed between it and an adjustable cross bar and adapted to support
the disc and connecting rod substantially as described.
4. In a pulp strainer the combination with the pulsating disc or diaphragm of
a connecting rod forked at its upper end to engage the disc and having its lower
end connected to and operated by a single crank pin or its equivalent substantially
as described.
5. In combination with a pulp strainer an oil box constructed and arranged
substantially as described to encase the crank shaft main bearing and crank pin
or pins or equivalent device for operating the pulsating disc or diaphragm.
6. In a pulp strainer the combination with an oil box adapted to encase the
crank shaft main bearings of a screw bolt and stirrup or equivalent devices operated
from without the oil box for adjusting the bearing bushes substantially as
described.
7. In a pulp strainer having a rocking or oscillating vat the arrangement in
combination with gearing for transmitting the rocking motion from the crank
shaft of an oil box secured to the end of the vat so as to move with the vat and
wherein the shaft bearings and gearing are encased substantially as described.
8. In a pulp strainer the combination with a crank shaft situated below the
vat, and having a crank pin or pins for operating the pulsating disc or diaphragm

page_text: of a second crank shaft and fixed connecting rod carried by the vat and operated
by gearing from the first mentioned crank shaft to impart rocking or oscillating
movement to the vat substantially as described.
9. In a pulp strainer a delivery box provided with a false or double bottom
furnished with a valve for periodically removing sedimentary matter substantially
as described.
10. In a pulp strainer a crank shaft constructed substantially as described with
reference to Figure 8 to provide for adjustment of the throw of the crank pin.
11. In a pulp strainer a crank shaft constructed substantially as described with
reference to Figure 9 to provide for adjustment of the throw of the crank pins.
12. In a pulp strainer the combination with a vat having a longitudinal
central supporting bar dividing the strainer plates and waste channels extending
along each side, of inclined adjustable sluice boards adapted to distribute the
pulp over the plates substantially as described.
13. In a pulp strainer a vat constructed as described with reference to Figure 7
with a side channel and a central waste channel extending lengthwise between
the strainer plates.
14. In a pulp strainer a vat constructed as described with reference to
Figures 4, 5 and 6 and in which the strainer plates are carried by cross bars or
bridges dividing the vat transversely and feeding and waste channels are formed
along the opposite sides.
1
1000
WALLACE FAIRWEATHER,
Of the Firm of Cruikshank & Fairweather,
Chartered Patent Agents,
62, St. Vincent Street, Glasgow, Agent for the Applicant.