Improvements in or relating to Apparatus for Filtering Sewage Sludge and other Substances.
Year: 1892

page_text: Date of Application, 8th Nov., 1892
Complete Specification Left, 5th Aug., 1893-Accepted, 9th Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements in or relating to Apparatus for Filtering Sewage
Sludge and other Substances.
We, JAMES BINGHAM ALLIOTT Engineer of Bloomsgrove Works, and JOHN
MCCLURE CALDWELL PATON, Mechanical Engineer also of Bloomsgrove Works,
Nottingham, do hereby declare the nature of this invention to be as follows:-
This invention has reference to improvements in or relating to apparatus in which
sewage sludge and other substances as for example the scum and settlings produced
in the manufacture of sugar, are treated in a filter press provided with a heavy loose
or following head that is operated and the filter press kept firmly closed by fluid
pressure usually by a hydraulic ram in connection with a hydraulic main provided
with an accumulator.
In the arrangements of such apparatus as heretofore devised, if for any reason,
such for instance as the bursting of a leather of the said hydraulic ram, or the
bursting of a pipe connected with the hydraulic main, the pressure of the hydraulic
ram on the said head should materially fall while the press was full of material
under pressure undergoing treatment, the ram would no longer keep the plates of
the press efficiently closed and the material contained in it would be squirted out in
all directions.
Now an object of this invention is to obviate this disadvantage. For this purpose
there is placed upon the.main supply pipe conveying sludge or other material under
pressure (hereinafter referred to as sludge) into the filter press or presses, a cock
or valve so arranged in relation to the accumulator that as the accumulator falls
and some little distance before it reaches the bottom of its stroke, it will close this
cock or valve and so cut off the further supply of sludge under pressure to the filter
press or presses. Another valve or cock is or may be also placed upon a branch
of the said supply pipe between the first mentioned cock or valve and the said press
or presses, this second valve or cock being so arranged that the accumulator as it
continues falling and after it has closed the first mentioned valve or cock but before
it reaches the bottom of its stroke, will open the second valve or cock and so free
the sludge within the pipes and filter press or presses from all pressure due to the
tension of such material.
According to another arrangement the sludge under pressure is admitted to the
filter press through a valve so constructed & arranged that the pressure of
the sludge will tend to close it while hydraulic or other fluid pressure will open it
and hold it open so long as this pressure is sufficient or more than sufficient to keep
the press firmly closed but upon the said fluid pressure falling to such a point that
it can no longer keep the press efficiently closed, the pressure of the sludge will
act to close such valve and shut of further supply of sludge to the press. An
arrangement of valve suitable for this purpose comprises two pistons of unequal
area between which the sludge passes and the greater of which is provided with a
stem subject to hydraulic or other fluid pressure.
Dated this 8th day of November 1892.
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicants.

page_text: COMPLETE SPECIFICATION.
Improvements in or relating to Apparatus for Filtering Sewage
Sludge and other Substances.
We, JAMES BINGHAM ALLIOTT, Engineer, of Bloomsgrove Works, and JOHN
MCCLURE CALDWELL PATON, Mechanical Engineer also of Bloomsgrove Works,
Nottingham, 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 has reference to improvements in or relating to apparatus in which
sewage sludge and other substances, as for example the scum and settlings produced
in the manufacture of sugar, are treated in a filter press provided with a heavy
loose or following head that is operated and the filter press kept firmly closed by
fluid pressure, usually by a hydraulic ram in connection with a hydraulic main
provided with an accumulator.
In the arrangements of such apparatus as heretofore devised, if for any reason,
such for instance as the bursting of a leather of the said hydraulic ram, or the
bursting of a pipe connected with the hydraulic main, the pressure of the hydraulic
ram on the said head should materially fall while the press was full of material
under pressure undergoing treatment, the ram would no longer keep the plates of
the press efficiently closed and the material contained in it would be squirted out in
all directions.
.
Now this invention has for object to obviate this disadvantage. For this
purpose there is placed upon the main supply pipe conveying sludge or other
material (hereinafter referred to as sludge) under pressure into the filter press or
presses, a cock or valve so arranged in relation to the accumulator that as the
accumulator falls and some little distance before it reaches the bottom of its stroke,
it will close this cock or valve and so cut off the further supply of sludge under
pressure to the filter press or presses. Another cock or valve is or may be also
placed upon a branch of the said supply pipe between the first mentioned cock or
valve and the said press or presses, this second cock or valve being so arranged that
the accumulator, as it continues falling, and after it has closed the first mentioned
cock or valve but before it reaches the bottom of its stroke, will open the second
cock or valve and so free the sludge within the pipes and filter press or presses from
all pressure due to the elasticity of the said pipes and press or presses.
In the accompanying drawings,
Fig. 1 is a side elevation; and
Fig. 2 a plan showing a sludge supply pipe with an arrangement of cocks of the
kind referred to and the accumulator by which such valves are successively
operated under the circumstances hereinbefore mentioned.
1 is a main supply pipe by which sewage sludge under pressure is conveyed to
a filter press (not shown) the head of which is held closed by hydraulic pressure
produced by an accumulator 2 as well understood. 3 is a cock for controlling the
How of sludge through the said pipe. This cock is normally open. 4 is a branch
pipe connected at one end to the pipe 1, open to the atmosphere at the other end,
and provided with a cock 5 that is normally closed. The cocks 3 and 5 are
respectively provided with lever arms or handles 3 and 5ª so arranged that when
the cocks are in their normal positions, they will be in the path of two arms or
tappets 6 and 7 respectively fixed to the accumulator 2. These arms or tappets
are so arranged, as shown, that should the fluid under pressure for any reason, such
as either of those herein before mentioned, be withrawn from the supply pipe

page_text: feeding the hydraulic ram used for closing the press, quicker than a further supply
of fluid can be supplied by the combined action of the accumulator and pump or
other means employed for feeding the accumulator, then, as the accumulator falls,
and some little distance before it reaches the bottom of its stroke, the arm or
tappet 6 will move the arm or handle 3* into the position shown and close the
cock 3 so as to shut off further supply of sludge to the filter press, after which the
arm or tappet 7 will come into contact with and move the arm or handle 5ª and
open the cock 5 so as to relieve the sludge within the filter press and connected
pipes of pressure due to the elasticity of the parts within which it was confined.
The arrangement is shown in its simplest form with the main supply pipe 1
running close to the accumulator 2 so that the arms or handles 3" and 5ª of the
valves 3 and 5 can be directly acted upon by the arms or tappets 6 and 7 on the
accumulator, but it will be obvious that in cases where it is more convenient to
place the accumulator at some distance from the range of piping 1, and cocks 3
and 5, the necessary motion for operating the said valves can be readily transmitted
from the accumulator by a simple arrangement of levers and rods or other equivalent
mechanism.
According to another arrangement the sludge under pressure is admitted to the
filter press through a valve so constructed and arranged that the pressure of the
sludge will tend to close it, while hydraulic or other fluid pressure will open it and
hold it open so long as this pressure is sufficient or more than sufficient to keep the
press firmly closed, but upon the said fluid pressure falling to such a point that it
can no longer keep the press efficiently closed, the pressure of the sludge will act
to close such valve and shut off further supply of sludge to the press. An
arrangement of valve suitable for this purpose is shown in Fig. 3 which shows the
valve in vertical section and one end of the filter press in side elevation.
8 represents the one end of the filter press and 9 the valve for controlling the flow
thereto of sludge under pressure. This valve is in the form of a hollow plug or
plunger closed at the top and arranged to move end ways in a cylinder 10 formed
with a branch 10ª that is placed in communication with the interior of the filter
press and with a branch 10° that is in communication with the external atmosphere.
The hollow plug or plunger is open at its lower end so that it is at all times in free
communication with the sludge supply pipe 1 and is formed with a lateral discharge
opening 9 through which the sludge can pass through the branch 10% of the
cylinder 10 into the press when the valve is in its lowermost position. The plug
or plunger is also formed with an external annular recess 9 by which the branch 10°
can be placed in communication with the branch 10b for the purpose of freeing the
sludge in the press of pressure after the valve has been automatically raised to cut
off the supply of sludge through the opening 9ª. The hollow valve 9 is connected
by a rod 11 with a smaller piston. 12 arranged to work endways in a cylinder 13 the
outer end of which is placed, by means of a pipe 14, in communication with the
hydraulic or fluid pressure cylinder the pressure in which normally serves to keep
the press closed.
With the arrangement described, when the pressure in the said hydraulic cylinder
is sufficiently great to keep the press firmly closed, the said pressure also acts with
sufficient power upon the piston 12 to cause it, through the rod 11, to keep the
hollow valve 9 pressed down to the bottom of its cylinder 10 and maintain the
opening 9 in the valve opposite the branch 10% of the cylinder 10 so that the sludge
can pass freely into the filter press 8. Should however the pressure in the
hydraulic main or in the hydraulic cylinder used for keeping the press closed fall,
the pressure of the sludge upon the hollow valve 9 will force this valve upwards to
such an extent as to move the opening 9" above the branch 10% and bring the
recess 9° opposite such branch thereby first cutting off the supply of sludge to the
press and then relieving the sludge that is in the press of pressure due to
the elasticity of the press and pipe connections.
Fig. 4 is a similar view to Fig. 3 illustrating a modified arrangement comprising

page_text: two pistons 9 and 9* of unequal area connected by a rod 9° and arranged to work
in the corresponding cylinders 10 and 10* the outer ends of which are in
communication with the atmosphere by the openings 10 and 10 respectively.
The larger piston 9* is provided with a stem 12" arranged to work in a
cylinder 13 the outer end of which is connected by a pipe 14, as in the previous
arrangement, with the hydraulic cylinder the pressure in which normally serves to
keep the filter press closed. The smaller piston 9 serves as a valve to control the
outlet 10 by which the sludge entering the cylinders between the pistons 9 9* by
the inlet 10, passes to the filter press.
The action of this arrangement is as follows:--
When the filter press is in action, the pistons 9 9* are held in the positions shown,
against a stop such as 15, by hydraulic pressure acting upon the stem 12ª but upon
such pressure falling below that necessary to keep the said press efficiently closed,
the pressure of the sludge upon the upper side of the larger piston 9* will cause
this piston to automatically descend and move the piston into a position in which
it will close the communication between the passages 10 and 10° and open
communication between the passage 10" and the top of the cylinder 10 having
outlets 10, thereby first cutting off the supply of sludge to the press and then
relieving the sludge in the press of pressure as before.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. In apparatus for filtering sewage sludge and other substances, the combination
with a filter press or presses kept closed against the pressure of the sewage sludge
or other substances by means of fluid pressure applied externally and produced by
an accumulator of a sludge supply pipe provided with a cock or valve so arranged
in relation to the accumulator that should the fluid under pressure be for any
reason withdrawn from the supply pipes quicker than a further quantity of fluid
can be supplied by the combined action of the accumulator and pump or other means
employed for feeding the accumulator, then the accumulator will, as it falls close
the said cock or valve and so cut off the further supply of sludge or other substance
under pressure to the filter press or presses substantially as hereinbefore described
for the purpose specified.
2. The combination with filtering apparatus constructed as specified in the
preceding claim, of a second cock or valve placed upon a branch of the said supply
pipe between the first mentioned cock or valve and the filter press or presses, this
second cock or valve being so arranged that the accumulator as it continues falling
and after it has closed the first mentioned cock or valve, but before it reaches-the
bottom of its stroke, will open the second cock or valve, and so free the sludge or
other substance within the pipes and filter press or presses from all pressure due to
the elasticity of the said pipes and press or presses substantially as herein described
for the purpose specified.
3. In apparatus for filtering sewage sludge and other substances, the combination
with a filter press kept closed against the pressure of the sludge or other substance
by means of fluid pressure applied externally in the manner described, of a valve
so constructed and arranged that the pressure of the sludge or other substance
passing through the valve case on its way to the press will tend to close the said
valve while hydraulic or other fluid pressure will tend to open the said valve and
will hold it open so long as this pressure is sufficient or more than sufficient to keep
the press efficiently closed, but upon the said fluid pressure falling to such a point
that it can no longer keep the press efficiently closed, and before that point is
reached, the pressure of the sludge or other substance will act to close the said
valve and shut off further supply of sludge or other substance to the press,
substantially as hereinbefore described for the purpose specified.
4. In apparatus for filtering sewage sludge and other substances, valves

page_text: constructed arranged and operating substantially as herein before described with
reference respectively to and shown in Figs. and 2; in Fig. 3; and in Fig. 4 of
the drawings annexed for the purpose specified.
Dated this 5th day of August 1893.
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicants.