Year: 1886

page_text: Date of Application, 8th Nov., 1886.
Complete Left, 8th Aug., 1887.
Complete Accepted, 20th Sept., 1887.
1, EDWARD ALFRED COWPER of No. 6 Great George Street, Westminster, in the
County of Middlesex, Consulting Engineer, do hereby declare the nature of this
invention to be as follows:-
The great expense attending disposal of deposited sludge from sewage has in many
cases prevented the adoption of satisfactory arrangements and when filter presses, such
as were introduced in 1853 or modifications of these, are used to produce compressed
cakes of sludge the labour and manipulation attending their use seriously interfere
with the disposal of the product.
The object of my invention is, to accelerate the process of pressing, to save the
expense of lime which is now sometimes added before pressing and to enable the filter
presses to be worked with comparatively little manual labour, thereby reducing the
cost of the cakes of solid sewage produced, and thus enabling the system of filter
prosses for sludge to be largely adopted for the disposal of sewage.
I introduce into the sludge passing into a sewage filter press a small quantity of
compressed air, and thus the process of filtration is greatly accelerated. The air. may
be admitted intermittently or in a small continuous stream during the whole or a part
of the time of admission of sludge.
I detach or assist in detaching the cakes from the cloths by introducing air or
water under pressure, behind the cloths so as to push off the cakes after the press has
been slightly opened, and this I accomplish by arranging through all the plates and
rings a passage connected to the draining grooves in the plates and then forcing air
or water under pressure into this passage which has the effect of pushing the cakes off
the cloths and thus saves manual labour. The air and more particularly water if it
is used, tends to clean the cloths, and displace any small solid particles that tend to
choke them, thus increasing their filtering power.
To assist in the discharge of the cakes upon the opening of the press, and to avoid
or reduce the amount of work to be done by the attendants now employed in detaching
the cakes from the cloths to which they more or less adhere, I use springs upon, or
recessed into, the faces of the plates, which, upon the opening of the press, push the
cloth forward at places, and thus cause the cakes to detach themselves from the cloths.

page_text: For opening and closing the plates of the filter press by power in order to dispense
with the manual labour which is now commonly required in this operation, I construct
the frame of considerably greater length than is usual, and I attach to the lugs on the
"follower" two endless chains one on each side of the inachine, these chains passing
over pulleys. On each side of the machine I attach another chain to the lugs of all
the plates, allowing sufficient length for the chains to hang down with a slack of
several inches between the successive plates when they are closed. When the
"follower" is is withdrawn by the pair of endless chains, the slack chains are pulled
tight and the plates are drawn apart with spaces between them sufficient for the
discharge of the cakes.
Or, I employ for opening and closing the plates, pawls carried on reciprocating
bars, the said pawls engaging seriatum lugs on the plates and moving them one at a
time a distance equal to the amount of space required for the discharge of a cake.
I put sufficient pressure on the plates to make a joint with the cloth or filtering
medium between them, by employing at one end a hydraulic or pneumatic cylinder of
a larger area than the working area of the plates themselves and applying the same
pressure of air or water, as is used in the press, to act in this cylinder, thus obtaining
the force required to resist the pressure in the press and to keep the joints tight.
To prevent any undue strain upon the chains, I employ stops, keys or cotters to hold
the "follower in its place on the long bars.
Although in the foregoing description I have referred chiefly to filter-presses for
treatment of sewage, I wish it to be understood that my invention may be used in
filter-presses applied for treatment of other materials.
Dated this 8th day of November 1886.
ABEL & IMRAY,
Agents for the Applicant.
Improvements in Filter Presses.
1, EDWARD ALFRED COWPER of No. 6 Great George Street, Westminster in the
County of Middlesex, Consulting Engineer do hereby declare the nature of this 30
invention and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement :—
The great expense attending the disposal of deposited sludge from sewage has in
many cases prevented the adoption of satisfactory arrangements and when filter
presses such as were introduced in 1853 or modifications of these are used to produce 3
compressed cakes of sludge the labour and manipulation attending their use seriously
interferes with the disposal of the products.

page_text: The object of my invention is to accelerate the process of pressing and to enable
the filter presses to be worked with comparatively little manual labour, thereby
reducing the cost of the cakes of solid sewage produced, and thus enabling the
system of filter presses for sludge to be largely adopted for the disposal of sewage.
With the sludge supplied to the filter press I introduce a small quantity of
compressed air admitting it by preference intermittently especially during the latter
part of the feed, this having the effect of clearing the cloths and accelerating the
filtration.
I detach or assist in detaching the cakes of sludge from the cloths by introducing
air or water under pressure, behind the cloths so as to push off the cakes after the
press has been slightly opened, and this I accomplish by arranging through all the
plates and rings a passage connected to the draining grooves in the plates and then
forcing air or water under pressure into this passage which has the effect of pushing
the cakes off the cloths and thus saves manual labour.
The air and more particularly water if it is used, tends to clean the cloths and
displaces any small solid particles that tend to choke them, thus increasing their
filtering power.
To assist in the discharge of the cakes upon the opening of the press, and to avoid
or reduce the amount of work to be done by the attendants now employed in detaching
the cakes from the cloths to which they more or less adhere, I use springs upon, or
recessed into, the faces of the plates, which upon the opening of the press, push the
cloth forward at places, and thus cause the cakes to detach themselves from the
cloths.
For opening and closing the plates of the filter press by power in order to dispense
with manual labour which is now commonly required in this operation, I construct
the frame of considerably greater length than is usual, and I attach to the lugs on the
"follower" two endless chains, one on each side of the machine, these chains passing
over pulleys. On each side of the machine, I attach another chain to the lugs of all
the plates allowing sufficient length for the chains to hang down with a slack of
several inches between the successive plates when they are closed. When the
"follower" is withdrawn by the pair of endless chains, the slack chains are pulled tight
and the plates are drawn apart with spaces between them sufficient for the discharge
of the cakes.
Or I employ for opening and closing the platos, pawls carried on reciprocating bars,
the said pawls engaging seriatim lugs on the plates and moving them one at a time a
distance equal to the amount of space required for the discharge of a cake.
I put sufficient pressure on the plates to make a joint with the cloth or filtering
medium between them, by employing at one end a hydraulic or pneumatic cylinder of
a larger area than the working area of the plates themselves and applying the same
pressure of air or water, as is used in the press, to act in the cylinder, thus obtaining
the force required to resist the pressure in the press and to keep the joints tight. To
prevent any undue strain upon the chains, I employ stops, keys or cotters to hold
the "follower" in its place on the long bars.
Although in the foregoing description I have referred chiefly to filter presses for
treatment of sewage, I wish it to be understood, that my invention may be used in
filter presses applied for treatment of other materials.
Such being generally the nature of my invention I will describe means of carrying
it out in practice referring to the accompanying drawings, which illustrate the
application of my invention to filter presses for sewage sludge.
Fig. 1 is an elevation, Fig. 2 is a plan, Fig. 3 is a front end elevation, and Fig. 4 is
a back end elevation of the filter press. Fig. is a section to an enlarged scale of
one end of the press. a, a, are the grooved plates which are covered with filter.
cloths, and b, b, are the rings interposed between the plates, maintaining between
them the spaces in which the cakes of sludge are formed. c, c are the horizontal bars
or guides upon which slide lugs projecting from the plates and rings. d is the
"follower" or strong plate at the back end of the row of plates, to resist the pressure
when the press is at work,

page_text: ,e are two tight endless chains or ropes passing over two pulleys, keyed on a
driving shaft h at the front end of the press, and over two similar pulleys on a shaft
at the back end of the press.
These endless chains are attached to pins; in the lugs projecting from the sides of
the "follower" d, so that when the shaft his driven in one or other direction the
"follower" d is caused to advance or retire. k k are two slack chains or ropes
attached to the lugs of the "follower" and also to the lugs of all the plates. The
chains are shewn in the drawings as consisting of flat links jointed together but
ordinary chains may be used, sufficient length being allowed for the chains or links
to hang down with a slack of several inches between the successive plates when they
are closed up together. When the "follower" is drawn back by the action of the
endless chains; the slack chains are pulled tight and the plates are drawn apart with
spaces between them sufficient for the discharge of the cakes.
When the "follower" is drawn forward by the endless chains, in the act of closing
the
press, it pushes all the plates before it, thus closing the whole press.
The shaft h is driven by spur wheel reversing gear with a sliding conical or other
friction clutch on a shaft driven by steam or other convenient power as shewn in
Fig. 2, so that it can be driven in either direction and stopped at the will of the
attendant by moving a hand lever. I make the friction clutch of relatively small
diameter capable of communicating sufficient power to slide the plates but little more
so that in case it be not released by the attendant, when the plates are closed together,
it shall then slip and so prevent breakage.
When the plates are closed, the "follower" is secured in its place by two strong
sliding bolts 7 actuated by the hand lever m, the said bolts shooting into slotted
holes in the tie bars n n. At the front end of the press is a hydraulic or pnenmatic
cylinder g, having a ram of large diameter and short stroke, the flat head of which
presses against the front plate of the row. This rain is actuated by the admission
into the cylinder through the cock 9', of compressed air of the same pressure as that
employed to force the sewage sludge into the press, or preferably by the admission of
water at the same pressure driven in by the compressed air or by pumps. The ram
is driven inwards by the pressure of the plates and "follower" when they are drawn
forward by the endless chains; and then when the "follower" has been secured by
its bolts, the pressure of air or water is admitted into the hydraulic cylinder, by the
cock g', forcing the ram outwards and pressing the plates tightly together, ready for
the admission of sludge. The diameter of the hydraulic cylinder is larger than the
diameter of the plates, so that it exerts a force superior to the internal pressure
produced when the sludge is forced into the press, and so keeps the joints tight while
the filtering is in progress. The two tie-bars n n which take the strain when the
pressure is on, are securely riveited to two short bars o o passing through lugs cast on
the hydraulic cylinder and secured with cotters. The said bars n n are also rivetted
to the slide bars c c.
The admission of sludge takes place through the cock p the pipe p¹ connected to
the cylinder, the pipe p² which is connected to the ram and works in a stuffing box,
and through a passage leading to a hole through the centro of the face of the ram as
shewn in Fig. 5. Each plate except the last one is provided with a hole through its
centre, so that a central passage for the admission of sludge is formed from end to
end, communicating with all the spaces between the plates.
For the discharge of the filtered water draining grooves are provided in the faces
of each plate leading to a hole q, through a lug at the bottom of the plate. The
rings interposed between the plates having similar lugs and holes, a complete channel
or passage is formed from end to end, except through the last plate which is solid.
Through the passages so formed the liquid squeezed out by the filter passes to a
corresponding passage q', through the head of the ram, with a pipe q³ working in a
stuffing box, through the pipe 9 and the cock q.
For the intermittent admission of air through the sludge inlet a double beat or other
suitable valve (Fig. 1) is connected to the air piper and compressed air reservoir,
and also to the pipe p' leading to the press; and the valve is caused to open

page_text: automatically at the desired intervals by the operation of a cam S caused to slowly
rotate by a worm and worm-wheel, driven by a separate strap from the engine. To
detach or assist in detaching the cakes from the cloths, arrangements are made for
the admission of air in a contrary direction through the water outlet passage q' by
means of a cock t, connected to the pipe 7 and to the compressed air reservoir.
method of using this portion of my invention is as follows:-
The
When the operation of filtering is at an end, and the press is to be opened for
discharging the cakes, the sludge inlet cock p is closed, the cam motion to valve r² is
stopped, the water outlet cock q* is closed, and the air cock is opened admitting
compressed air through the pipes 9' and , and the passages q¹, and to the grooves
behind the cloths.
The pressure is then let off from the hydraulic cylinder, through the cock g', and
the pressure of the air behind the cloths immediately forces the plates slightly apart
and so forces the ram home into its cylinder, at the same time pushing the sludge
cakes off the cloths. This action is only momentary, as the compressed air escapes at
the circumference of the plates as soon as the pressure of the hydraulic cylinder is
relieved and the rain forced in; the air cock t is then closed the bolts holding the
"follower" d are withdrawn, and the friction clutch is thrown in, causing the endless
chains to draw back the follower and separate seriatim all the plates and rings in the
manner hereinbefore described, by power without the intervention of manual labour.
Instead of air, water under pressure may be admitted behind the cloths for the same
purpose.
As a further means of automatically loosening the sludge cakes from the cloths, I
connect each ring b to the plate a next behind it, by means of two slack bolts u, or by
slack chains, links, or other equivalent device, so that when the plate is pulled back
in the process of opening the press, the plate starts before the ring, and the latter then
follows a short distance behind the former.
Another appliance for assisting in the automatic discharge of the cakes consists of
tapered brackets or fingers » Fig. 5 cast on the inside of the rings and projecting
inwards touching the cloth when the press is closed. On the separation of the plate
and ring when opening, these fingers being between the cake and the cloth, have the
effect of pulling the cake away from the cloth.
Another appliance for the same purpose consists of one or more flat springs w w
Fig. 5 let into recesses in the faces of each plate behind the cloths. These springs are
pressed back in their recesses by the pressure of the sludge against the cloths during
the process of filtering; but when the pressure is relieved, and the separation
commences, the said springs exert their force in pushing the cloths a short distance
away from the plates, and so assist in loosening the cakes."
Instead of straight springs on each face an annular plate with radial spring arms
projecting from it may be used, the whole being let into a recess in the face of the
plate, and the spring arms being so arranged that the ring and arms lie flat in
their recesses in the plate when the pressure is on, these springs heave the plate away
from the face when the pressure is let off.
Figs. 6 and 7, and Figs. 8 and 9, shew an alternate arrangement for opening and
closing the plates by means of pawls carried on reciprocating bars. Fig. 6 is an
elevation, Fig. 7 is a plan, Fig. 8 is an elevation shewing the position of the "follower"
when the plates are all closed, and Fig. 9 is a back end elevation. AA are two
pawls for pulling the plates back in opening the press, B B are two pawls for pushing
the plates forward in closing the press. The said pawls are mounted on the blocks C
which are carried by the reciprocating bars D D one on each side of the press. The
blocks CC having slots in them through which the bars D D pass, are capable of
sliding along the bars but this sliding is opposed by an adjustable amount of friction
between each block and its bar produced by means of the spring E and two set screws,
or other equivalent appliances.
The bars D D receive by means of cranks and connecting rods driven by power, a
uniform reciprocating end motion, greater than the required motion of the plates.
The friction arrangement. being adjusted so as to give, just sufficient power to the

page_text: pawls to pull or push one plate and the adjoining ring, which slide in the usual
manner supported by lugs on guide bars, the pawls move one plate and ring through
the open space, and pull or push them against the row of plates.
The motion of the pawls and blocks being thus arrested, the bars continuing their
motion, slide through the blocks for the remainder of their stroke, then in the return
stroke of the bars the blocks, are carried with them but. occupying new positions, so
that on the completion of the return stroke the pawls engage with the next plate. In
this manner the whole of the plates are opened seriatim and closed in the same
manner.
"
When all the plates and the "follower are closed, the latter is locked in position
ready to resist the pressure, by means of a butting piece or eccentric cam F mounted
upon a short rock shaft provided with a hand lever.
The rings may be connected to the plates by the loose bolts herein before described
and shewn in Figs. 1 and 2, or they may be unattached, in which case each plate
would push a ring in front of it, instead of pulling a ring behind it.
The hydraulic cylinder for giving the necessary pressure for making the joints is
equally applicable to this arrangement as to that first described.
Having now particularly described and ascertained the nature of this invention and
in what manner the same is to be performed, I declare that what I claim is :-
1. In combination with a filter press a pair of endless chains or ropes connected to
each of its plates and capable of being moved by power in either direction for
separating and closing up the plates as herein described.
2. In combination with a filter press for the purpose of separating and closing its
plates, pawls mounted with adjustable friction on bars moved to and fro by power as
herein described.
3. In a filter press the use of springs or other moveable pieces, on, or recessed into
the faces of the plates, to assist in the automatic discharge of the cakes of compressed
material, substantially as herein described.
4. In a filter press in order to facilitate the detachment of the pressed cakes from
the filtering cloths admitting behind the cloths air or water under pressure exceeding
that in the filter substantially as described.
5. In combination with a filter press a hydraulic or pneumatic cylinder and ram
arranged to apply the necessary force for pressing the plates together, such ram being
of larger area than the working area of the platos, and subjected to the same pressure
as the material operated on by the filter press, substantially as described.
6. In combination with a filter press, apparatus substantially as herein described,
for the intermittent introduction of air.
DL: OL 1
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