Improvements in Pulp Strainers of Paper Making and like Machines.
Year: 1894

page_text: Date of Application, 7th Mar., 1894
Complete Specification Left, 7th Dec., 1894-Accepted, 12th Jan., 1895
PROVISIONAL SPECIFICATION.
Improvements in Pulp Strainers of Paper Making and like
Machines.
I, DAVID NOBLE BERTRAM, of St. Katherine's Works, Sciennes, Edinburgh, in
the County of Midlothian, North Britain, Engineer, do hereby declare the nature
of this invention to be as follows:-
This invention relates to improvements in pulp strainers of paper making and like
machines, and has for its object to provide means whereby the refuse matter is
washed off the face of the strainer plates and is prevented from again coming in
contact with the face of the said plates as is the case with strainers having an
oscillating motion imparted to them.
In accordance with my said invention the pulp flows into a cast iron vat in which
is 'fitted, as usual, the strainer plates; the said plates being preferably formed with
their slits running parallel to the apex of the plates but at an angle to the flow of
the pulp therefrom.
The vat with the said strainer plates is arranged to work either level or at an angle,
which angle can be arranged more or less as desired so as correspond to the
quantity of water used in the pulp, and to other circumstances which affect the flow
of the pulp over the face of the said strainer plates.
To effectually wash any refuse matter off the face of the strainer plates which
may catch on the slits thereof, I impart an intermittent motion to the vat, which
motion lowers one side of the vat, so as to cause a wash into the refuse channel, the
said motion returning the vat to the position from which it started.
To obtain the said intermittent motion for the vat and plates, 1 so mount the
strainer as to enable it to be moved from a centre which may consist of a shaft or
of two pins or trunnions mounted in line with each other. The motion may be
derived from the diaphragm actuating shaft by means of suitable gearing, preferably
worm gearing, so as to reduce speed and so give a suitable number of washes
per minute, and on one of the worm wheel spindles I employ a regulating connecting
rod arrangement which gives more or less incline to the strainer plates, so as to
cause more or less of a wash over the said plates.
One arrangement of actuating mechanism may be as follows:-I mount a pulley
on the diaphragm shaft and cause it to drive another pulley mounted on a spindle
having a worm fixed thereon. This worm is in gear with a worm wheel mounted on
a cross spindle having another worm mounted on it and which worm gears into another
worm wheel mounted on a spindle, placed parallel to the diaphragm shaft; the said
spindle has also niounted on it a disc crank having a crank pin fixed in it. The said
crank pin works in a slot formed in the lower end of an adjustable connecting rod, the
upper end of which is suitably connected to the vat, in such a manner, as to enable
the revolving crank pin to lift up or tilt the vat while describing the top part of
its revolution, and thereafter to run free in the slot for a certain time when the
strainer is level. The vat after being tilted or lifted up is brought back to its
normal position by means of an adjustable spring actuated connecting rod or lever
mounted and connected to the opposite side of the vat, that is to say to the side of
the vat which is lowered every time the vat is tilted.
The adjusting of the connecting rods may be effected by any suitable means, such
as a right and left handed nut and screw arrangement or otherwise, and the returning.

page_text: spring may also if desired be provided with an adjusting arrangement, so as to enable
the strainer to be worked from the level or from any desired angle and so enable
the strainer to be altered so as to fit the quality of pulp and the quantity of water
used in the straining process.
Dated this 6th day of March 1894.
JOHNSONS,
115, St. Vincent Street, Glasgow, Petitioner's Agents.
Improvements in Pulp Strainers of Paper Making and like
Machines.
I, DAVID NOBLE BERTRAM, of St. Katherine's Works, Sciennes, Edinburgh, in
the County of Midlothian, North Britain, 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 pulp strainers of paper making
machines and has for its object the construction of a strainer which will overcome
the objections hitherto attached, more or less to the various classes of strainers at
present in use, that is to say, that in accordance with my said invention no hanks,
knots, or unboiled fibres will remain on the surface of the plates, nor come in
contact with the strainer plates, after they have been separated from the clean
pulp.
The revolving strainer and other strainers having an oscillating motion, hitherto
used, cause the pulp around them, and on their surface, to be kept in a state of
agitation and in contact with the plate surfaces, and thus permit of the liability of
the deleterious matter being sucked through the strainer plates and passed on to
the wire of paper making machines,
This invention has also for its object to provide means whereby the refuse matter
is washed off the face of the strainer plates and is prevented from again coming in
contact with the face of the said plates as is the case with strainers having an
oscillating motion imparted to them.
In accordance with my said invention the pulp flows into a cast iron vat in
which is fitted, as usual, the strainer plates; the said plates being preferably formed
with their slits running parallel to the apex of the plates but at an angle to the flow
of the pulp therefrom.
The vat with the said strainer is arranged to work either level or at angle,
which angle can be arranged more or less as desired so as to correspond to the
quantity of water used in the pulp, and to other circumstances which affect the flow
of the pulp over the face of the said strainer plates.
To effectually wash any refuse matter off the face of the strainer plates which
may catch on the slits thereof, I impart an intermittent motion to the vat, which
motion lowers one side of the vat so as to cause a wash into the refuse channel, the
said motion returning the vat to the position from which it started.
But in order that, my said invention may be more readily understood and easily
carried into effect I will proceed, to describe the same with reference to the
accompanying drawings:-
:―
Figure 1 is a back elevation, Figure 2 a plan, Figure 3 is an end elevation and
Figure 4 a front elevation of a pulp strainer constructed in accordance with my said
invention.
Referring to the said drawings, I employ a cast-iron or other vat A in which the
plates B are fixed and which is carried by a bracket C at either end, the lower
ends of which are mounted on circular bushes and pins D so that it will move freely,
the centre of the bushes and pins D being.exactly that of the shaft E which actuates

page_text: b
the diaphragm, so that whatever position the vat A may take, the diaphragm
remains in the same relative position to the plates B and shaft E. The strainer
plates B are formed with their slits 6 running lengthwise of the plates and arranged
in angular rows as shown in Figure 2 so as to give a more effective strainer or the
slits may be formed in an equivalent manner.
To the said vat A are connected two rods G, H, the rod G being actuated by the
crank pin J. In the box K there is an arrangement of two sets of worm and worm
wheels k driven by belt and pullies from the shaft E so as to reduce the speed of
the crank disc J to the necessary number of revolutions required for causing an
intermittent raising and lowering of the vat A, plates B'and diaphragın.
The crank pin J in the disc as it approaches the perpendicular line, comes
in contact with the connecting rod G, and tilts the vat A up at the back, thus
lowering the front, and causing a wash of pulp over the plates B the one way
only, thereby dislodging any refuse matter which may have settled on the plates B
into the channel L, from which the refuse matter is allowed to flow to auxiliary
through a regulating flat valve and pipe fixed to front of vat A, the pipe
discharging it into a square box or other vessel.
When the vat A is lowered at the front it is brought back to its normal position
by the connecting rod H and spiral spring H', which is compressed as the back of the
vat A is raised, by the connecting rod G, thus when the crank pin J passes over the
top centre and begins to descend, the connecting rod G is still in contact with the
crank pin J as the compression of the spiral spring H' thus begins to take effect,
and the vat A comes gradually back to its original position without any shock, and
from the point of release, the connecting rod G describes the revolution of the
crank pin J until it comes again in contact with the top of the slot y formed
in the lower end of the connecting rod G this causing the raising motion again,
and so on repeating the former movements. In some cases I may employ two
connecting rods H and springs H' with one raising or lifting rod G.
The strainer can be set to work with the plates B at any desired angle or level,
such being arranged by the right and left hand nuts and screws N formed on the
connecting rods G and H, and by the use of these nuts and screws more or less incline
can be given to the plates B while the strainer is at work.
While I have thus described in this particular instance the movement adopted in
causing the raising and lowering of the vat, it can be performed in various ways, for
instance by hanging the front side of the sole plate which carries the entire strainer,
and at the front side raising and lowering the whole strainer from the sole plate by
cam, crank or other means.
•
The spreading of the pulp is effected by a sluice R fixed in the channel R¹ and
the pulp is run in over the edge of the vat A and through below the sluice R which
regulates the flow equally all over the length of the apex of the plates.
The arrangement is such that the clean pulp is passed through the plates B before
the objectionable or deleterious matter rests thereon, such matter being carried
away by impetus of the stuff into the channel L which is effected by the quantity
of pulp passing into the channel which is usually employed when the strainers are
working in connection with an auxiliary, and in which I mount zine plates having
longitudinal or cross slits through which the heavy dirt passes into the under channel
and remains there until it is cleaned out, when washing up, or it may be run off by
a cock. The flow from the upper channel is conducted to the auxiliary strainer
which cleans the pulp in the usual manner as hitherto. It will thus be seen that
the dirt or deleterious matter when once clear of the plates B does not again come
in contact with the straining surfaces as is the case with oscillating and revolving
strainers.
The whole arrangement thus provides a strainer in which there is not the
objection in causing the pulp to wash backwards and forwards over the surface of
the plates, bringing with it the refuse matter, and thereby subjecting such refuse
matter necessarily to the straining action of the strainer, and allowing it to pass on
to the paper machine with the clean pulp, as when the front of the vat is lowered

page_text: and does not rise above the level from which it began to descend, the refuse matter
is not carried over the surface of the plates, as is the case with an oscillating motion
lowering both sides of the vat alternately.
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
1st. In pulp strainers for paper making machines, the means whereby the back
of vat is intermittently lifted and lowered, so as to prevent the refuse matter from
being carried back over the strainer plates, as described and shown.
2nd. In pulp strainers for paper making machines in which the vat A is mounted
on pivots D, connecting the vat at the back to the top ends of the adjustable
connecting rods G, H; the rod G being driven through the medium of the crank
pin J and slot g, and the other rod or rods H provided with a spiral spring H',
whereby the back of the vat is intermittently lifted and lowered, as described and
shown.
3rd. In pulp strainers for paper making machines, the right and left hand screws
and nuts N, whereby a greater or lesser lifting and lowering of the vat may be
effected, as described and shown.
Dated this 6th day of December 1894.
JOHNSONS,
115, St. Vincent Street, Glasgow, Applicant's Agents.