IMPROVEMENTS IN FILTER PRESSES
Year: 1876

page_text: LETTERS PATENT to Samuel Henry Johnson, F.C.S., of Lea Bank Works
Stratford, in the County of Essex, for the Invention of "IMPROVEMENTS IN
FILTER PRESSES."
Sealed the 1st September 1876, and dated the 4th July 1876.
PROVISIONAL SPECIFICATION left by the said Samuel Henry Johnson at
the Office of the Commissioners of Patents on the 4th July 1876.
SAMUEL HENRY JOHNSON, F.C.S., of Lea Bank Works, Stratford, in the County
of Essex. "IMPROVEMENTS IN FILTER PRESSES."
0
This Invention has for its object improvements in filter presses.
For this purpose I form a filtering chamber or closed tank by means of a series
of frames when filtration under high pressure is desirable. I.employ frames by
preference of an annular form. The frames are prepared with fair surfaces on both
sides, and when in use are pressed together between two end plates. Thus a
chamber is built up, and in the case of annular frames being used the chamber is
cylindrical. The frames are arranged to slide upon guide bars, and a screw is
employed to press them together.
In each of the frames aforesaid is fixed a filter, such filter consists of a corrugated
or ribbed plate, or a porous wirework mat, or of some other suitable core or form
covered with a filtering fabric or medium, which is so supported by the core or
form that the pressure employed in the process of filtration shall not injure the
filtering medium. This core or form I call a filter mat. On the lower part of each
of the filter mats is fixed an outlet pipe or nozzle for the purpose of conducting
away the liquid which passes through the filtering medium, care being taken that
the filtering medium is so securely closed round the outlet pipe which passes
through it that none of the unfiltered liquid can pass away with the filtrate.
This outlet nozzle passes liquid tight through the frame. The filter such as
above described should not completely fill the frame, but one or more spaces should
be left, the function of which is to admit the free passage of the liquid to be filtered
from the inlet to the whole of the interior of the filtering chamber and thus
establish communication with each of the filters, by this means I avoid the com-
plication of pipes and unions which are necessary when pressure filters are formed
on the multicellular type. At the same time by making the filtering chamber
sectionally in frames, each frame provided with a filter, I am enabled after filtering
to remove the cakes of solid matter filtered from the liquid, which then fill the
[Price Sdl

page_text: spaces between the filters, without removing the filters from their respective frames,
this being effected by simply separating the frames from one another by sliding
them along the guide bars, when the cakes will drop out, or are easily removed; all
that is necessary then to reinstate the filter in working order is to push the frames
together with the screw or other suitable mechanism for that purpose.
To facilitate the formation of the joints between the frames and the end plates,
and between the frames themselves, so that the joints may be made by simply
pressing the plates together, I form one of the joint surfaces as a bead projecting
from the frame or end plate, the other surface being formed in a bed of softer metal
embedded in a groove or channel provided in the frame for that purpose.
To ensure uniform pressure, instead of pumping into the filter chamber direct,
I interpose an accumulator between the pump and the press, this may consist of a
cylinder provided with a loaded piston or of a reservoir placed at a superior level
so that the column of liquid shall be sufficient to give the maximum pressure at
which it is deemed desirable to work the press.
In most cases of filtration if the full pressure were employed at the commence-
ment of the operation some of the solid matter would pass through the filter. To
avoid this inconvenience I employ a valve for the admission of the liquid into the
filter chamber capable of fine adjustment, and I also provide the filter chamber
with a pressure gauge so that the admission of the liquid into the filter chamber
may be regulated to the required pressure. It is also well, as has been practised
with other pressure filters, to provide the filter chamber with a valve adjustably
loaded, so that if the pressure in the chamber becomes too great the liquid will
overflow at the valve.
In one of the frames is screwed an air cock for the purpose of permitting the
escape of the air when the filter chamber is being filled with the liquid at the com-
mencement of the filtration.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Samuel Henry Johnson in the Great Seal Patent Office on the 4th
January 1877.
SAMUEL HENRY JOHNSON, F.C.S., of Lea Bank Works, Stratford, in the County
of Essex. "IMPROVEMENTS IN FILTER PRESSES."
This Invention has for its object improvements in filter presses.
For this purpose I form a filtering chamber or closed tank by means of a series
of frames when filtration under high pressure is desirable. I employ frames by
preference of an annular form. The frames are prepared with fair surfaces on both
sides, and when in use are pressed together between two end plates; thus a cham-
ber is built up, and in the case of annular frames being used the chamber is cylin-
drical. The frames are arranged to slide upon guide bars, and a screw is employed
to press them together.
In each of the frames aforesaid is fixed a filter, such filter consists of a corrugated
or ribbed plate, or a porous wirework mat, or of some other suitable core or form
covered with a filtering fabric or medium, which is so supported by the core or
form that the pressure employed in the process of filtration shall not injure the
filtering medium. This core or form I call a filter mat. On the lower part of each
or the filter mats is fixed an outlet pipe or nozzle for the purpose of conducting
away the liquid which passes through the filtering medium, care being taken that
the filtering medium is so securely closed round the outlet pipe which passes
through it that none of the unfiltered liquid can pass away with the filtrate.
This outlet nozzle passes liquid tight through the frame. The filter such as
above described should not completely fill the frame, but one or more spaces should
be left, the function of which is to admit the free passage of the liquid to be filtered
from the inlet to the whole of the interior of the filtering chamber and thus establish

page_text: communication with each of the filters, by this means I avoid the complication of
pipes and unions which are necessary when pressure filters are formed on the multi-
cellular type. At the same time by making the filtering chamber sectionally in
frames, each frame provided with a filter, I am enabled after filtering to remove
the cakes of solid matter filtered from the liquid, which then fills the spaces between
the filters, without removing the filters from their respective frames, this being
effected by simply separating the frames from one another by sliding them along
the guide bars, when the cakes will drop out, or are easily removed, all that is
necessary then to reinstate the filter in working order is to push the frames together
with the screw or other suitable mechanism for that purpose.
To facilitate the formation of the joints between the frames and the end plates, and
between the frames themselves, so that the joints may be made by simply pressing
the plates together, I form one of the joint surfaces as a bead projecting from
the frame or end plate, the other surface being formed in a bed of softer metal
embedded in a groove or channel provided in the frame for that purpose.
To ensure uniform pressure, instead of pumping into the filter chamber direct,
I interpose an accumulator between the pump and the press, this may consist of
a cylinder provided with a loaded piston or of a reservoir placed at a superior
level so that the column of liquid shall be sufficient to give the maximum pres-
sure at which it is deemed desirable to work the press.
In most cases of filtration if the full pressure were employed at the commence-
ment of the operation some of the solid matter would pass through the filter, to
avoid this inconvenience I employ a valve for the admission of the liquid into the
filter chamber capable of fine adjustment, and I also provide the filter chamber
with a pressure gauge so that the admission of the liquid into the filter chamber
may be regulated to the required pressure. It is also well, as has been practised
with other pressure filters, to provide the filter chamber with a valve adjustably
loaded, so that if the pressure in the chamber becomes too great the liquid will
overflow at the valve.
In one of the frames is screwed an air cock for the purpose of permitting the
escape of the air when the filter chamber is being filled with the liquid at the com-
mencement of the filtration.
Figure 1 is a side elevation, and Figure 2 is a plan, both partly in section, of a
filter press constructed according to my Invention.
a and bare end frames bolted to foundations, and also secured the one to
the other by the bars c, c. The frame a is also represented in Figure 3, and the
frame b in Figure 4. Two of the tie bars c, c, also serve as guides, upon which
the rings d, d, and also the disc or platten D are able to slide; e is a powerful
screw working in the end frame a, and by it the rings & and the disc or platten D
can be forced together towards the end frame b.
Figure 5 shows to a larger scale a section of parts of three of the rings d, viz.,
the parts at the side of the rings where they are supported upon the tie bar c, and
the parts at the bottom where the outlet is formed. Each ring has a raised rib (¹
on one side of it, and on the other side there is a groove d³ filled with soft metal,
so that when the rings are pressed together a fluid tight joint is made; d, ds, are
lugs with which the rings are provided in order to support filter mats f. A front
view of one of the rings d with its filter mat f in place is seen at Figure 3,
some of the lugs are attached with screws which can be readily taken out, so
that the filter mats can easily be separated from the rings wben required. The
filter mats consist of wire woven or twisted together into a mat sufficiently open
to allow liquid to percolate very freely through it and yet sufficiently close to
prevent the filter cloth penetrating the interstices. Each of these mats is sown
up in a filter cloth so as to be completely enclosed except that a nozzle f¹ rivetted
on to the bottom of the filter mat is allowed to project through the cloth, and the
edges of the cloth are clipped around the nozzle by a nut f. The lower end of
the nozzle is coned and it fits into a hole formed to receive it in the substance of
the ring & where it is secured by a lock nut f³. Thus a free passage is provided

page_text: from each filter mat to the exterior of the filter by which the liquid passing
through the filter cloths can flow out. The nozzles f¹ and parts in connection
therewith are shown in section in Figure 5. The ends of the press are closed by
end plates g, g, one of which rests against the frame b, and the other against the
disc or platten D. A front view of one of these plates is shewn at Figure 6, and a
section at Figure 7, a portion of it is also shewn to a larger scale in section at
Figure S.
The end plates g are so formed around the edge that the rings & may fit against
them fluid tight. The surface of the plate is covered in each case with a filter cloth
which is secured by means of a divided hoop g³:
When the cloth is in its place resting on the corrugations of the plate, the hoop
is expanded by means of the right and left handed screw at g*, and is so made to
nip the edges of the cloth all round. The liquid which passes through the cloth
can escape to the exterior of the press by the passage 92. The matter to be
filtered is forced into the press past a stop valve h. The casing or shell of this
valve is fitted into the end frame b, it passes through the end plate g and the
filter cloth upon it, and the edges of the cloth around the hole are clipped by a
nut /¹.
Figure is a longitudinal section of this valve with its casing or shell, and
Figure 10 is an end view of the latter. The valve as will be seen is a cone actuated
by a fine screw so that the flow of the matter to be filtered into the filter can be
very accurately adjusted; he is a socket to receive a pressure gauge to indicate the
pressure in the filtering chamber. The matter to be filtered is forced by pumps
into a cylinder similar to that of an hydraulic press and having a ram loaded up to
the highest pressure to be employed in filtering.
When the filter press is ready the matter is let into it by gradually opening the
valve, and the valve is adjusted so that the pressure within the filter press may rise
but very slowly; the full pressure is not allowed to come on to the filter press until
the end of the operation. When liquid ceases to pass away from the filter press
the valve at h is closed, the filter is taken apart, and the solid cakes which will be
found between the rings d, d, are removed, after which the filter press is closed and
locked together again, and is ready for another operation.
A modification in the way of constructing the rings d and the parts in connection
therewith is shown by the Figures 11, 12, 13, and 14.
Figure 11 is a front view, and Figure 12 is a back view of one of the rings,
Figure 13 is a vertical section, and Figure 14 is an horizontal section of several rings
and other parts in connection therewith.
The rings are here formed with internal flanges d', against which in each case a
corrugated metal plate f" rests; this plate is or takes the place of the filter mat; it
is slightly attached to the flange d by two screws, easily removed for cleaning.
The other side of the flange d is grooved with radial grooves; is a rail formed
at the top of each ring. When the filter press is being set up for work a filter
cloth is hung on this rail; it is sufficiently long to cover the ring on both sides, and
its width is just such that it can hang between the guides c, c.
When the press
is closed and locked up by the pressure screw e the edges of the filter cloths become
nipped all round between the rings d,, and so fluid-tight joints are made; dare
grooves in the rings d to let the liquid pass freely away; they communicate with
the outlet orifices (7.
In the centre of each plate f* there is a bolt with a circular hole in it, and there
are corresponding holes in the filter cloths; f*, fx, are flanged ferrules, which are
inserted into the holes in the plates f; there are nuts on the ferrules, which when
screwed up nip the cloths against the bosses of the plates f, and so make fluid-
tight joints. The holes through the ferrules are sufficiently large to give free pas-
sage to the matter to be filtered from one end to the other of the press. The tubular
ferrules in this arrangement serve the same purpose as the spaces left around
the filter mats shewn in Figure 3, and in each case a single connection serves for
the admission to the filter press of the matter to be filtered.

page_text: Having thus described the nature of my said Invention, and the manner of per-
forming the same, I would have it understood that I do not confine myself to the
exact details, but I claim-
First. The construction of filter presses formed of a filtering chamber or close
tank built up with a series of open frames pressed together as described, each frame
being provided with a separate filter mat or core, substantially as described.
Second. The construction of filter presses, substantially as described.
In witness whereof, I, the said Samuel Henry Johnson, have hereunto set my
hand and seal, this Third day of January, in the year of our Lord One
thousand eight hundred and seventy-seven.
SAM². H. JOHNSON. (L.S.)