Improvements in and relating to Filter Presses and similar Filtering Apparatus
Year: 1896

page_text: Date of Application, 3rd Oct., 1896
Complete Specification Left, 3rd July, 1897-Accepted, 3rd Dec., 1897
PROVISIONAL SPECIFICATION.
"Improvements in and relating to Filter Presses and similar
Filtering Apparatus."
I, JOHN WILLIAMSON, of 65 West Regent Street, Glasgow, in the County of
Lanark, Chemical Engineer, do hereby declare the nature of this invention to be
as follows:-
This Invention which relates to filter presses and similar filtering apparatus has
for its object the provision of means for preventing clogging or choking of the
interstices of the filter cloth in filtering impure water, liquors or juices such as river
or canal waters, turbid chemicals or other liquors, and sugar juices containing
flocculent albuminous gummy or like matters which do not readily form cakes in a
filter press.
To that end either I mount a shaft to pass through the series of plates in the
press (which may be of the ordinary form) so that it is capable of rotation or
oscillation and in each filtering chamber between said plates I fit a brush or series of
brushes upon arms or spokes of a wheel secured upon a central shaft;
or in each filtering chamber I insert a shaft or spindle capable of a reciprocating
motion, to which I fit cross arms having brushes attached.
These brushes may or may not be maintained out of contact with the surface of
the filter cloth during filtration and they may or may not be kept in motion during
filtration according to the character of the material being filtered.
The liquor to be filtered is maintained under a head or pressure and the filtered
liquor after passing through the filter cloth may be drawn off at either the top or
bottom of each chamber according to the particular manner in which I brush the
face of the filter cloth.
When the discharge of filtered liquor decreases owing to the partial clogging of
the filter cloth the admission of liquor is stopped and that remaining in the filter
chambers is run off, air being freely admitted, when the filtered liquor is drawn
from the top of the plates. The shaft or shafts with the brushes attached is or are
then rotated, oscillated or reciprocated and owing to the relief of pressure on
filter chamber sides of the filter cloth combined with the pressure of filtered liquor
retained on the other side, the filter cloths sag and come into sufficiently close
contact with the brushes to enable the brushes to detach the material adhering to the
cloth. The filtered liquor in the clear liquor spaces oozes through the cloth and serves
to wash away the obstructing material.
When I draw the filtered liquor from the bottom of the plates the admission of air
to the filter chambers is manipulated so as to ensure the necessary pressure of the
cloths on the brushes.
The filtering operation is then recommenced by turning on cocks or valves to
admit the liquor under pressure into the filter chambers as previously described.
The operations of alternately passing the liquor through the filtering cloth and of
stopping filtration and cleaning the surfaces of the filter cloths may be effected
automatically at predetermined intervals to suit the nature of the liquor to be filtered

page_text: by periodically throwing into and out of gear the driving belt or other mechanism
which operates the rotating, oscillating or reciprocating shaft or shafts and by the
same movements opening or closing the cocks or valves controlling the admission of
the liquor and discharge of the sludge, such movements being capable of varying
the several operations I have described.
WALLACE FAIRWEATHER,
of the Firm of Cruikshank and Fairweather, Chartered Patent Agents,
62 Saint Vincent Street, Glasgow. Agent for the Applicant.
"Improvements in and relating to Filter Presses and similar
Filtering Apparatus."
I, JOHN WILLIAMSON, of 65 West Regent Street, Glasgow, in the County of Lanark,
Chemical Engineer, do hereby declare the nature of this invention and in what
imanner the same is to be performed, to be particularly described and ascertained in
and by the following statement:—
This Invention which relates to filter pressure and similar filtering apparatus has
for its object the provision of means for preventing clogging or choking of the
interstices of the filter cloth in filtering impure water such as river or canal waters,
liquors or juices, turbid chemical or other liquors and sugar juices containing
flocculent albuminous gummy or like matters which do not readily form cakes in a
filter press.
To that end either I mount a shaft to pass through the series of plates in the press
(which may be of ordinary form) so that it is capable of rotation or oscillation and in
each filtering chamber between said plates I fit a brush or series of brushes upon
arms or spokes of a wheel secured upon the central shaft; or in each filtering chamber
I insert a shaft or spindle capable of a reciprocating motion, to which I fit cross arms
having brushes attached.
These brushes may or may not be maintained out of contact with the surface of
the filter cloth during filtration and they may or may not be kept in motion during
filtration according to the character of the material being filtered.
The liquor to be filtered is maintained under a head or pressure and the filtered
liquor after passing through the filter cloth may be drawn off at either the top or
bottom of each chamber according to the particular manner in which I brush the
face of the filter cloth.
When the discharge of filtered liquor decreases owing to the partial clogging of
the filter cloth the admission of liquor is stopped and that remaining in the filter
chamber is run off, air being freely admitted, when the filtered liquor is drawn from
the top of the plates. The shaft or shafts with the brushes attached is or are then
rotated, oscillated or reciprocated and owing to the relief of pressure on filter chamber
sides of the filter cloth combined with the pressure of filtered liquor retained on the
other side, the filter cloths sag and come into sufficiently close contact with the
brushes to enable the brushes to detach the material adhering to the cloth. The
filtered liquor in the clear liquor spaces oozes through the cloth and serves to wash
away the obstructing material.
The filtering operation is then recommenced by turning on cocks or valves to
admit the liquor under pressure into the filter chambers as previously described.
In the accompanying drawings which illustrate the invention,
Figures 1 and 2 are respectively a longitudinal section and end elevation of my
improved press, where provision is made for the brushes to rotate.

page_text: Figure 3 is an elevation showing the general arrangement for causing the brushes
to oscillate.
Figure 4 is an elevation and part section of one of the frames and also of one of
the wheels which carry or hold the brushes.
Figure 5 is an elevation and part section of one of the plates upon which the
filtering cloth or other medium is stretched.
Figures 6 and 7 are enlarged cross section and elevation of one form of perforation
or grating which is beneficially applied in the construction of iny apparatus.
Figures 8 and 9 are a cross section and elevation of plate, grating and centre
flanges, showing the method of fitting on the cloth watertight and of securing the
flanges free from liability to rotate.
Figure 10 is a section of the spokes of the wheel, showing the method of holding
the brush and allowing of the adjustment of the same.
Figure 11 is an end view of the rack and pinion gearing which is fixed on or forms
the outer rim of the circular gratings.
Figure 12 is a section of the shaft attached to the pinion showing how it is fixed
to the edge of rim of the plate.
Figure 13 is a longitudinal section and part elevation of my form of apparatus
when the plates are square and the brushes are manipulated in a reciprocating
manner.
Figures 14 and 15 are the respective end elevations of this form of apparatus.
Figure 16 is an elevation and part section of the frames thereof shewing also the
method of holding and adjusting the brushes.
Figure 17 is a horizontal section of the same.
Figure 18 is an elevation and part section of the plates of this form of apparatus.
Figure 19 is an enlarged section of the arrangement for regulating the admission
of water or other liquid while the brushes are at work.
Figure 20 is a section of the plates, and the gratings, shewing in this form of
apparatus how the position of the grating is altered.
Figures 21 and 22 are respectively end and side elevation of an apparatus with re-
volving brushes, showing attached thereto one form of arrangement for automatically
performing the movements or operations necessary when it is desired to stop
filtration and brush the cloth.
The apparatus resembles in general contour an ordinary filter press and comprises
the usual framing, zl, with plates Y and gratings Z upon which latter the filter
cloth or other filtering mediuin is stretched.
Through the centre of the press I insert the shaft a which varies in form through-
out its length as follows:-From the outer end to the part marked a¹, it is round.
Between a and a² it assumes a square shape with rounded edges as shewn in section
in figure 9. Between a² and a' it is of a similar square shape but reduced in size.
The centre holes in the wheels b which carry the brushes, are shaped to suit this
shaft so that the wheels while rotated by the shaft possess a free lateral motion.
When the plates Y and frames X, X', are screwed up tight and the shaft a inserted
till the point firmly rests upon the end of the journal at provided for it, the shaft
is then prevented from working out by the roller as, which is fixed on by the screwed
pin . The brass flanges o are made large enough to allow the square part of the
shaft to revolve freely without coming in contact with them. On the shaft emerging
from the press, a gland a' is provided to prevent any leakage of the liquids from the
inside. On the outside end are fixed two pulleys as and a", one loose and the other
firmly secured. An arin a attached to the bracket a" holds a rod a for shifting
the belt by means of an ordinary fork a", actuated by the handle a¹.
The liquid to be filtered is admitted by means of the valve d and channels di and
d into the filtering chambers, in which are the wheels b, holding the brushes, the
clear liquid passing in the usual way through the filter cloth which is supported by
the frames X, X, or plates Y. When the deposit upon the cloth becomes so great as
to render it necessary to be removed, the valve d is shut, and the valve f opened.
This allows the liquid inside the chambers to be run off by the channels and the..

page_text: valve. When this is done, the valve ƒ is shut, the wheels with the brushes set in
motion and the cock g opened by means of the rod g¹. The cloths at this stage sag
against the brushes with sufficient pressure for those latter to remove the deposit
therefrom which is run off by the channel and the cock g.
If necessary a supply of pure water, or of the unfiltered material, can be admitted
by the cock h, and channels A', h, for the purpose of assisting the brushes, such
liquid escaping by the cock g.
In exhausting the chambers of their contents prior to the brushes being set in
motion, it is necessary to admit air and this is done automatically by means of a
rubber and gridiron valve l, such valve being fitted with an upturned tube P, for the
conservation of any liquid which may pass the valve during iltration. The filtered
liquid, contrary to usual practice, ascends by the petty channels, as shewn in
figures 5 and 18, and escapes by the flat pipes n,' into the gutters m, said gutters
being supported by brackets attached to the fixed head X and the loose head X.
These gutters are preferably made light in weight, as in opening out the press, they
must of necessity be first removed. Each plate Y and the fixed and loose head X,
X, are provided with a cock K', which by means of the channel K, enables all the
filtered liquid behind the cloth to be removed when desired. It is not absolutely
necessary that the filtered liquid be removed from the top of the plates, but in
general practice it has been found that such method is the preferable one.
The emptying of the filter chamber causes the cloths or other filtering material to
press against the brushes, for the purposes of being cleaned, but if the cloths sag so
much as to press with too great a force against the brushes, the cloths must be
stretched over the plates with greater tightness and the method I adopt to effect that
is illustrated in Figures 6 and 7. At certain distances in the rim of the plate 1 drill
small holes, which I fill up again with tightly fitting wooden pins k as shewn at
figures 6 and 7, preferably of a hard reedy nature. I then pull the cloths tightly
towards these pins and fix them there with suitable nails or tacks.
For the purpose of fixing the brushes to the revalving wheel or wheels b, I make
the spokes of said wheels in the form shewn in section in Figures 4 and 10, that is to
say U-shaped, small bolts 6 being entered through slots in the U-shaped sides in
order to clamp the brushes. When the nuts on the bolts 6s are slackened, the brush
can be removed, set in the proper position and retained there firmly by again
screwing up the nuts 63. The rim of the wheel is made with as many openings as
possible consistent with strength, to enable the water or unfiltered liquid used in
brushing the cloths to freely escape to the effluent channels.
The brushes employed may be any ordinary form of brush suitable to the
particular form of spoke adopted. The hair or bristles of the brushes may be of any
description provided it is firm enough for the purpose of brushing the cloths and .it
may be constructed of metal, according to the nature of the liquid to be filtered.
In fixing the brushes in the spokes it is necessary to allow the bristles to project a
sufficient distance beyond the spoke and the spoke must have sufficient clearance
within the frame to allow of this projection as it is desirable that the cloths should
not come in contact with the spoke but with the brush contained therein.
In securing the cloths to the centre of the plates and rendering them water-tight
use is made of the general form of flanged nuts for this purpose, but as provision
must be made for preventing them from being unscrewed and thereby slackened by
the revolving of the internal brush wheels, I furnish the female nut with a slot c' as
shown in Figure 8 the length of which may be double its width. The male screw is
provided with four or eight similar slotted holes c² any one of which will correspond
with the slot in the female screw when they are tightened up. The jointing at
is preferably effected by thin india-rubber washers c, so that in tightening up
sufficient play is allowed to bring one of the holes in the male screw exactly above
the slot in the female screw, while the joint is kept perfectly tight. When this is
done a pin e' is dropped into the hole in the plate specially bored to receive it and
as it passes through the two slots they become locked and the male screw is unable
then. to work out.

page_text: In the usual design of filter presses the surface of the plates upon which the cloth
rests, is generally grooved in one or a combination of directions, this being performed
upon the surface of the plate itself. In my improved apparatus I make the plates
Y with a recess on both sides and into this recess I place a framework or grating Z
such as illustrated in Figures 5, 6, 7 and 8. The inetal against which the cloth rests
during filtration and which has the effect of retarding filtration at that spot, is
reduced to as small a size as possible, in doing which it assumes any of the forms
shown in Fig. 5 or cf the two forms shown in Fig. 18. I also construct these
gratings so as to allow of a free open space between the back of such and the surface
of the plate this being done by providing the back of the gratings with several small
projections p' which serve to support the grating without interfering materially with
this clear space. The object of this arrangement is to ensure perfect freedom for the
filtered liquid to escape from the apparatus and to enable filtration to be conducted
at a correspondingly low pressure.
I also take provision for shifting the position of the projecting parts of these
frames by slightly rotating then while the brushes are being revolved and the cloth
is in contact therewith or simultaneously with the starting of the brushes to revolve
or oscillate. For this purpose I provide the outside rim of the grating with teeth p,
as shown in figures 6 and 11, so as to form a circular rack in which works the
pinion 7. This pinion is actuated by means of the outside wheel r¹, which is either
a toothed wheel gearing into a similar wheel on the next plate, or is provided with
snugs to accomodate a chain as at fig. 12: Motion is imparted to the toothed wheels
by means of the handle r, the shaft attached to which is supported by the bracket r°,
which is bolted to the fixed head, all as shown in fig. 2. The toothed wheel 10 may
be replaced by a wheel with sougs if a chain is used, the mode of affixing the latter
being shown in fig. 22. The chain after going round the last wheel r', passes round
an idle wheel 11 which is capable of adjustinent within or on the slotted bracket 12
attached to the fixed head. If it is desired to open out the filter the wheel 11 is
shifted along the slot as far as possible by which means the chain can be freed from
the wheels and replaced when the filter is closed up again. In the case of toothed
wheels being employed, these can be provided with a square eye corresponding to a
square end on the spindle so that they can be simply removed before opening out
the filter.
The arrangements for shifting the position of the filter cloths relatively to the
plates or frames is the subject of a pending Application for Patent and is not herein
claimed.
The channels for the admission of the unfiltered liquid to the 6ltering chambers
are usually made round, but in my apparatus where the plates are circular in form, I
make these channels di,, circular also, but wide and shallow; and in the two end
frames this rectangular channel is formed into the circle where the inlet valve and
air valve are respectively attached. The advantage gained is that the petty
channels d2 and 2, can be made larger and more numerous, as shown in Fig. 4,
affording in the case of slightly impure water, where the flow is great, quick access to
and egress from the filtering chambers.
The channel A, Fig. 1, for the admission of the water or unfiltered liquid used in
washing the surface of the cloths while brushing is formed below the main inlet
channel d', in the centre as shown in Figs. 4 and 5. For the purpose of causing this
water or unfiltered liquid to impinge upon the top of the cloth, or in whatever
direction it is found that this water or unfiltered liquid serves best to scour the face
of the cloths, I incline the petty channels h², in such a way as to effect this purpose.
In squeezing the plates and. frames together I adopt the usual plan, namely, I apply
the compressing power by means of a strong screw X2 working in the standard X
which supports one end of the side bars, as shown in Fig. 13, or at regular intervals.
I provide the fixed end fraine X of the press with snugs s, to which are adapted the
bolts 8. These bolts fit into corresponding snugs 82, on the loose end or frame
enabling the plates and frames to lie tightly screwed close together.
As the time occupied in emptying the chambers of their liquid contents and

page_text: thereater removing the deposit from the face of the cloths by the rotation or
oscillation of the brushes inust be reduced to a minimum, for the admission
of the unfiltered liquid I employ a valve constructed as shown at d, in Fig. 1,
and for the removal of the contents of the filtering chambers prior to brushing
the cloths, I employ a valve constructed as shown at f, Fig. 1. In both cases
the valves are of the circular gridiron type, but in the case of the valve d, the
movable plate d is on the exterior side of the fixed plate d', while in the case of
the valve f the movable plate is on the interior side of the fixed plate . The
object of this arrangement is that when the valve d is required to be kept tightly
closed, the pressure of the liquid itself tends towards that purpose, and similarly in
the case of the valve f. Springs d and fo are employed to ensure the valves working
tightly, but the removable spindles are of necessity different in construction, as shown,
as the springs exert their power in opposite directions. Handles d' and are used
for opening and closing these valves, and projecting pins d' and serving to regulate
the extent of movement.
Instead of revolving the brushes, they may be oscillated or rotated backwards and
forwards to such an extent that every part of the surface of the cloth may be
thoroughly brushed. To effect that object I adopt the arrangement shown in Fig. 3.
The bar for supporting the franes and plates on one side is extended beyond the
screwing-up nut on the fixed head of the press and this extension forms a shaft for
two pulleys 2 the former of which rides idly and the crank is connected to the centre
shaft a, by the crank and the connecting rod t. The revolution of the wheel or
pulley imparts the necessary motion to the brushes, the manipulation of which
otherwise, and the general construction throughout being all as herein before.
described.
In order to brush the face of the cloths in a reciprocating manner I adopt the form
of press shown in Figs. 13, 14, 15. The plates Y and gratings Z are made square,
the inlet channel DI being formed in snug pieces at the top corner and the outlet for
the unfiltered liquid prior to brushing of the cloths, and for the brushing from the
cloth. being formed in snug pieces at the opposite bottom corner, as shown at F¹,
Fig. 16.
The frame B for holding the brushes is of square or rectangular form and provision
is made on the top for hooking it on the rod B2 by means of the tongue B, attached
to the end of the rod which is inserted in an opening at the top of the frame. The
brushes are fixed in this frame horizontally, back to back, and are kept firmly in their
place by a loose plate B³, tightened up by the small bolts and nuts B. The rod B²
passes through a gland and stuffing box B7 at the top of the frame and terminates in
a square head B³ with a rectangular slot running through it parallel to the line of the
inlet channel. Into this slot is inserted a rectangular bar A, the reciprocating motion
of which is imparted to the brushes for cleaning the cloths. The brushes are kept
moving in a straight line equally into the sides of the press frame, the heads or points.
of these pins fitting into corresponding grooves in the sides of the brush frame. The
centre of the fixed cross bars and the loose plates are perforated with longitudinal
holes as at Be fig. 17 to enable the washings from the cloths to escape freely to the
channel F. The reciprocating motion is imparted to the rectangular bar A from a
pulley A² which revolves on a shaft A", which is an extension of one of the side bars
for supporting the plates. The pulley A is connected with a lever A by the
connecting rod A³ and to the other end of the lever A is attached another connecting
rod A5 whose upper end is connected with the bar A. The lever A is supported by
a shaft A which extends beyond the back standard. At this end of the shaft is
attached a crank A7, which by means of a connecting rod AB, actuates the corres-
ponding end of the rectangular bar A. A standard guide A10 on the fixed head, and
another guide A on the back standard serve to impart a thoroughly vertical motion
to the rectangular bar A.
The manipulation of the different valves and the starting and stopping of the
brushes for the purpose of cleaning the cloths is effected in a manner similar to
that adopted when the brushes revolve or oscillate. An air valve L is provided for

page_text: the automatic admission of air to the filtering chambers.
A handle bar A1, moving on a pivot attached to the fixed head, controls a fork A
which throws the driving belt on or off the fast and loose pulleys A¹ and A¹
The filtered liquid is caused to ascend passing throngh the petty channels
(Fig. 18)
and the pipes a into suitable gutters such as previously described. A cock is
provided for emptying the chambers formed behind the cloths,
For the purpose of stretching the cloths over the face of the plates, small holes
are provided and used as previously described.
The same form of perforated framework or grating may be inserted into the recesses
in the plates as previously described in the case of an apparatus with revolving
brushes and as illustrated in Fig. 18.
In order however to shift the position of the projections pl of the gratings Z they
must be moved horizontally and the method I adopt to effect this is illustrated
in Figs. 13, 14, 18 and 20. The gratings Z are made with recesses for the reception
of a corresponding square nut R¹. This nut is screwed on the end of a spindle R
after the spindle has been passed through the stuffing box R2 and gland R³, the
former being bolted to the edge of the plate which is bored to receive the rod R.
The outer end of this rod is provided with a square slotted head R, through, which is
inserted the rectangular bar R. This bar passes through slotted heads on each plate"
and is provided at hoth ends with slippers K. The slipper at the fixed end of the
press moves horizontally between two brackets R, attached to the fixed head X while
the slipper at the loose end X¹ of the press moves between two bars R³ which project
from one of the legs of the back standard. The lateral motion. is imparted to the
bar R5 by means of the handle R which slightly rotates the shaft R10. To this shaft
is attached two arms or levers R", the ends of which move in corresponding slots in
the slipper R at the front end and in a slot in the bar R at the back end. The
gratings Z are made at the bottom so that they rest upon the plate at as few points
as possible so as to reduce friction to a minimum and minimise the power required to
rotate the shaft R 10.
The channel H, Figs. 16 and 19, for the admission of water or the unfiltered liquid"
used in washing the surface of the cloths while brushing it formed in snugs H² at
the top corner opposite to the channel which forms the inlet channel for the
unfiltered liquid. "The water or unfiltered liquid may enter the filtering chamber by
the duct H³, or to this duct or ducts may be attached a small copper pipe H*
perforated with numerous small holes which tend to distribute the washing liquid
over every part of the cloth. In order to regulate the admission of the washing.
liquid, the duct H is conically drilled at the mouth as at Hs and opposite this duct
there is bored a screwed hole H into which is screwed the screw H5, the end of which
is made to fit tightly at the mouth of the duct H. The screw H5 is actuated by the
milled handle H and the hole H is kept water-tight by the jam nut H.
The plates Y and frames X, X, of this forin of apparatus may be squeezed
together in either of the ways previously described.
The valve d, Fig. 14, for the admission of the unfiltered liquid and the valve f for
emptying the chambers of their contents prior to brushing are both made as herein-
before described.
The filtering medium employed in my improved apparatus may be made of any
material according to the degree of purity of the filtrate desired and according to
the nature of the liquid to be filtered provided it possesses sufficient flexibility
to sag towards the brushes when the filtering chambers are emptied of their contents.
Cotton cloth has been found to be most snitable, but any other textile material can
be used, including that woven from any kinds of wire provided it fulfils the conditions
already named.
The opening and shutting of the valves d, f, g, h, the shifting on and off the belt
by means of the forks a, A, and the rotation of the gratings behind the cloths,
being operations occuring in the same regular order and at certain defined intervals
of time, it is possible and desirable that such operations be performed by mechanical
neans, working automatically and with the least possible manual attention. A.

page_text: convenient means for attaining this purpose is shown at figures 21 and 22. To the
fixed end or plate X of the press is attached a cylinder v, in which works a piston 4
rendered watertight by any of the usual methods. The piston rod is pressed down
by the weights and extends beyond the weights far enough to enable it to work
always within the bracket 3 attached to the upper flange of the cylinder. From the
bottom of the cylinder there runs a small channel 4, to the valve box v. In this
valve box there works a slide valve , the position of which allows either the
admission of the water entering the valve box by the pipe v into the cylinder, or the
free escape of the water in the cylinder by means of the channel v and the screw-down
valve v. To the hottom of the weights are attached several strong knuckle jointed
catches, vo, vl. When the valve is at its lowest position and the entrance of the
water forces up the piston the catch 10 on its way up raises the end of the lever vlt
thereby depressing the cam via until the toe of the cam falls below the projection 14
on the rod v15, this rod being attached to the valve v. When the catch reaches the
end of the upward stroke of the piston, the lever 1 is released and drawn back by
the springs thereby raising the rod us and the valve to such a position that
communication is made between the inside of the cylinder and the valve v. The toe
of the cam 13 is simultaneously thrown out of contact with the projection 14 by the
pin which being fixed pushes out the toe of the cam, on the ascent of the latter.
The rod is prevented from falling too far down by the catch u" which falls under
a corresponding projection on the rod. There being a free escape for the water below
the piston the weights press the piston down, until the bottom of the catches come in
contact with and press down the arm vo which is attached to the catch v18. The
latter is slightly rotated and releases the rod which by its own weight depresses the
valve v. The piston is then forced up again and the like operations repeated. The
valve v can be so regulated as to determine the time in which the downward stroke
of the piston is effected, the upward stroke being quickly performed. The regulation
of this valve will depend upon the nature of the liquid being filtered. The sooner the
pores of the filtering material are clogged up, so much the quicker must the piston
be allowed to descend. The pressure of the water or oil admitted by the pipe must
be great enough to raise the weights and perform the other work entailed upon it as
hereinafter described.
Upon the opposite side of the bracket are fixed two brackets 20, one to the
frame and the other to the upper flange of the cylinder. Through these brackets
pass two square rods 21 and 2 both loaded by weights such as 23. From the
rod projects a pin at 24 in contact with the rod which opens and closes the
valve d. The lower end of this rod presses upon the bar or rod 25 on the valve f
and by means of the rod v2 which is jointed at 7, and notched at 3, where it has
free contact with the rod, opens and closes the bottom valve f. When the piston
descends to a predetermined point the weights 2 depress the arm 20 thereby
rotating the catch and allowing the rod v to descend by its weight a sufficient
distance to shut the valve d and open the valve f. The rod is released and
allowed to drop to a predetermined position by the weights depressing an arm
similar to but fixed at a wider angle to the catch attached thereto. The effect
of the weight 2 acting on the arm which holds the rod 2 causes the rod 22 to
descend in a predetermined space of time after the descent of the rod t, such space
of time being sufficient to empty the contents of the filtering chambers. The
descent of the rod u depresses the arm and in doing this pushes out the rod
which allows the rod vs on the spindle of the valve f to return to its former position
being counter-weighted at . In addition to actuating the spindle of the valve f
the descent of the rod v depresses the bar as thereby opening the valve g, so that
the brushings of the cloths escape by that valve. The descent of the rod 2 also
depresses the bar which by the means shown, shifts the position of the belt
fork thereby throwing the fast pulley a into play. It also depresses the bar
which by the means shown opens the cock h to admit water, or unfiltered liquid.
The shaft which is rotated slightly on the depression of the. bar is also
provided with a short, bar us from which hangs loosely the pawl working into the

page_text: ratchet wheel 40. The partial rotation of this ratchet wheel is transmitted to the
chain wheel 0 by means of two shafts and a universal joint as shown in Fig. 22, the
rotation of the wheel 10 by the means already described causing the gratings behind
the cloths to rotate slightly. After a predetermined interval of time the piston v
descends to the point at which the valve is allowed to drop and the piston then
ascends as described. On the ascent of the weights, the catch v raises the inner end
of the lever in doing which by the means shown the rod v is raised to its former
position and secured there by the catch behind 30. On the weights ascending
further the catch raises the inside end of the lever 43 and by the arrangement
of levers and devices shown restores the rod v to its original position where it is
retained by the catch, and the weight on the rod v25 is thus enabled to open
the valve d for the inlet of the unfiltered liquid and filtration then proceeds as
before.
A cylinder and piston such as v, v', may also be attached to an apparatus having
the form shown in Fig. 3 and may also be attached to an apparatus having the form
shown in Figs. 13, 14, 15, and by similar arrangement of levers, catches, &c. perform
all the operations necessary in each particular form of apparatus for brushing the
cloths all as herein before described.
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. A filter press constructed and arranged to operate substantially as described
under several modifications with reference to the accompanying drawings.
2. In a filter press or like filtering apparatus the provision of movable brushes
or like means operating as described for periodically cleaning the surfaces of the
filter cloths or other filtering modia, whilst admission of the unfiltered liquid is
stopped and the filtering chambers are emptied or partially emptied.
3. In a filter press or like filtering apparatus the arrangement within the
filtering chambers of brushes or brush wheels carried by a central shaft and adapted
to be thereby rotated or oscillated in contact with the surfaces of the filter cloths
substantially as and for the purpose set forth.
4. In a filter press or like filtering apparatus the arrangement within the
filtering chambers of brushes or brush frames carried by a reciprocating shaft and
adapted to be reciprocated in contact with the surfaces of the filter cloths substan-
tially as and for the purpose set forth.
5. A filter press or filtering apparatus furnished with brushes or like means for
cleaning the surfaces of the filtering medium and provided with means for
intermittently and automatically bringing into operation the brushing devices
whilst suspending filtration substantially as described.
JT.... 1907
WALLACE FAIRWEATHER,
Of the Firm of Cruikshank & Fairweather,
Chartered Patent Agents,
62 Saint Vincent Street, Glasgow. Agent for the Applicant.