IMPROVEMENTS IN FILTER PRESSES
Year: 1878

page_text: LETTERS PATENT to William Freakley, of Longton, in the County of Stafford,
Engineer, for the Invention of "IMPROVEMENTS IN FILTER PRESSES."
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Sealed the 30th July 1878, and dated the 22nd May 1878.
PROVISIONAL SPECIFICATION left by the said William Freakley at the Office
of the Commissioners of Patents on the 22nd May 1878.
William FreakLEY, of Longton, in the County of Stafford, Engineer. “IMPROVE-
MENTS IN FILTER PRESSES."
According to this Invention I filter potter's clay, Portland cement, paraffin, oil-
cake, hops, yeast, sewage, and other fluid or fluid-containing materials by a kind
of continuous process by means of an apparatus constructed and operating as
follows:-
On a suitable foundation plate I fix a hollow cylinder or tube open at the ends,
and formed in the middle on its outside with a piston which can work in an outer
cylinder about half the length of the inner cylinder; this outer cylinder when in
extreme position at either end of the inner cylinder makes joint with a flange on
each end of the said inner cylinder; these flanges may form part of brackets for
fastening the inner cylinder to the bed plate; the short outer cylinder can by rack
and pinion or other suitable means be made to move from one end of the inner
cylinder to the other.
The inner cylinder is, except as regards the space occupied by the piston, formed
with screw, or spiral, or other grooves all over its outer circumferential surface, and
holes are formed from the bottom of these grooves to the interior of the cylinder.
Over these grooved surfaces I place filtering cloths or other filtering appliances.
Supposing the outer cylinder is in its extreme position at one end of the apparatus
then the "slip" or other material can be forced into the annular enclosed space
between the inner and the outer cylinder, and when sufficient force is applied the
water or other fluid will be expelled through the filtering cloth and the grooves in the

page_text: surface of the inner cylinder, and will by the small holes through the cylinder
penetrate into the interior of it, and escape at the end.
When the matter has been filtered to the desired extent the short outer cylinder
is by the rack and pinion (or other gear) moved to the other end of the apparatus,
forming joint against the flange on the inner cylinder at that end, when the same
process may be gone through. I thus obtain a practically continuous supply of
filtered matter.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Freakley in the Great Seal Patent Office on the 22nd
November 1878.
WILLIAM FREAKLEY, of Longton, in the County of Stafford, Engineer. "IMPROVE-
MENTS IN FILTER PRESSES."
According to this Invention I filter potter's clay, Portland cement, paraffin, oil-
cake, hops, yeast, sewage, and other fluid or fluids containing materials by a kind
of continuous process by means of an apparatus constructed and operating as
follows:-
On a suitable foundation plate I fix a hollow cylinder or tube, open at the ends,
and formed in the middle on its outside with a piston which can work in an outer
cylinder about half the length of the inner cylinder; this outer cylinder when in
the extreme position at either end of the inner cylinder makes joint with a flange
on each end of the said inner cylinder; these flanges may form part of brackets for
fastening the inner cylinder to the bed plate; the short outer cylinder can by rack
and pinion or other suitable means be made to move from one end of the inner
cylinder to the other.
The inner cylinder is, except as regards the space occupied by the piston, formed
with screw, or spiral, or other grooves all over its outer circumferential surface, and
holes are formed from the bottom of these grooves to the interior of the cylinder.
Over these grooved surfaces I place filtering cloths or other filtering appliances.
Figure 1 of the accompanying Drawing is a vertical longitudinal section of an
apparatus constructed according to this Invention.
A is a cast-iron foundation plate, and B a hollow metallic cylinder bolted thereto
by means of feet or brackets B¹ at each end; C is a hollow metallic cylinder about
half the length of the cylinder B, and bored out to receive the piston D fitted or
*formed on the outside of the cylinder B in the middle of its length; E is a rack
fixed on the outside of the short cylinder C, and F is a pinion fixed on a shaft F¹,
carried in suitable bearings ou the bed plate A immediately under the piston D.
By turning the pinion F in one direction or the other the cylinder C can be moved
towards one end of the apparatus or the other; or instead of rack and pinion I
may employ worm and worm wheel, or screws working in nuts attached to outer
cylinder, or in centre of inner cylinder; or I may employ other gear, or the
--

page_text: direct action of steam, hydraulic, or other pressure on one or two pistons working
in cylinders underneath the bed plate A, or on each side, or inside the inner cylinder
centrally, such piston or pistons being connected to the short cylinder .C in any
suitable manner.
The outside of the inner cylinder B is (except as regards the piston D) formed or
provided with one or more spiral, or straight, or other grooves or recesses, which by
holes communicate with the interior of the cylinder B; these grooves are in this
case intended to represent one or more screw threads cut or cast in the metal, but
the grooves might also be formed in gutta percha sheeting wrapped round the
cylinder B, or in or between wood lagging staves secured to the outside of the
cylinder by means of metal hoops or otherwise, or in or between segments of brass,
copper, plaster of Paris, or other material, all according to the material to be filtered
and the pressure used. Over the grooved surface so formed I place filtering cloths G,
or other filtering appliances; and in order to protect the cloths from injury from
the edges of the grooves, especially when a high filtering pressure is employed, brass
or copper wire gauze may be placed underneath the filtering cloths; the wire gauze
is also beneficial in increasing the filtering surface, because the liquid will pass
through the gauze when it rests on the parts between the grooves.
In the Drawing the ends of the cylinder C are made to form joint with india-
rubber or other packing rings inserted in grooves b in the brackets B'. It is
however obvious that the brackets B¹ may be formed with projecting round bosses,
which enter the ends of the cylinder C as pistons, and when of the same diameter
as the middle piston D there will be equilibrium when the cylinder C is at one end
of the apparatus or the other, so that there will be no tendency for it to move
back.
Figure 2 is a part view of such an arrangement. b' is a projecting boss on a
bracket B, and fitting like a piston in the cylinder C.
The liquid to be filtered may enter from the supply pipe c (Figure 1), which by
swivel joint is connected to the pipe c, which latter again by swivel joint is con-
nected to the pipe e, which latter is connected by swivel joint to the cock f; or
the supply pipe c may be connected with the cock f by means of a flexible hose
pipe.
In Figure 2 the liquid is made to enter by the interior of the cylinder B through
the pipe cand cock f
Supposing the outer cylinder C' is in its extreme position at one end of the
apparatus, as shewn, then the "slip" or other material can be forced into the
annular enclosed space between the inner cylinder B and the outer cylinder C, and
when sufficient force is applied the water or other fluid will be expelled through
the filtering cloth and the grooves in the surface of the inner cylinder B, and will
by the small holes through the cylinder penetrate into the interior of it, and escape
at the open end.
When the matter has been filtered to the desired extent the short outer cylinder
C is by the rack E and pinion F (or other gear) moved to the other end of the
apparatus, forming joint against the flange B' on the inner cylinder at that end,
when the same process may be gone through. I thus obtain a practically continuous
supply of filtered matter, as the clay or other sedimentary matter may be removed
from the filtering cloth at one end of the apparatus while filtration is going on at
the other end.
By this construction of press I am also enabled to use pressures altogether beyond
the reach of filter presses of ordinary construction.
The apparatus for forcing the liquid into the apparatus may conveniently consist
of one or more force pumps, and of a horizontal or vertical accumulator or barrel
having a ram or piston working it, the ram or piston being weighted to the required
pressure, and the accumulator being so connected to the pump gear that it shall
control the stroke or working of the pumps, as is well known and understood; the
liquid pumped into the accumulator enters thence into the filtering machine.

page_text: T
And, having thus described and ascertained the nature of this Invention, I declare
that I claim,
Firstly. The construction of filtering apparatus, wherein the filtering takes place
alternately at the two ends in an annular space between a hollow inner cylinder,
having a piston on the middle of its length, and a hollow outer cylinder fitting on
said piston, substantially as set forth.
Secondly. Alternate or continuous filtration by means of apparatus consisting of
a stationary inner hollow cylinder having a piston fitting in an outer movable
cylinder, the liquid being forced from the annular space between the two cylinders
into the interior of the inner cylinder, substantially as set forth.
Thirdly. The construction of the inner cylinder, and the mode of application of
filtering appliances thereto, as set forth.
In witness whereof, I, the said William Freakley, have hereunto set my hand
and seal, this Twentieth day of November, in the year of our Lord One
thousand eight hundred and seventy-eight.