U.S. patent number 3,825,382 [Application Number 05/256,248] was granted by the patent office on 1974-07-23 for filter press.
This patent grant is currently assigned to Maxwell Davidson Limited. Invention is credited to Maxwell Wingate Davidson.
United States Patent |
3,825,382 |
Davidson |
July 23, 1974 |
FILTER PRESS
Abstract
A press for expressing liquids from solids or for forming
moulded blocks comprises a frame including a facing pair of upper
and lower platens, a filter cloth extending across the lower
platen, and a fluid expansible bellows device located between the
platens and serving to press material against the filter cloth. The
bellows device is comprised by the novel arrangement of a first
flexible diaphragm connected to the upper platen and forming a
fluid chamber with the upper platen, and an inflatable bag member
between said first flexible diaphragm and the lower platen. The
inflatable bag has an upper diaphragm wall back-to-back with said
first diaphragm and a lower diaphragm wall for pressing material on
the filter cloth, the inflatable bag and the fluid chamber being in
fluid communication; and the bellows device includes an inlet for
pressure fluid.
Inventors: |
Davidson; Maxwell Wingate
(Edinburgh, EN) |
Assignee: |
Maxwell Davidson Limited
(Edinburgh, GB)
|
Family
ID: |
27506900 |
Appl.
No.: |
05/256,248 |
Filed: |
May 24, 1972 |
Current U.S.
Class: |
425/84; 100/118;
425/389; 100/211 |
Current CPC
Class: |
B28B
3/003 (20130101); B28B 7/46 (20130101); B01D
29/684 (20130101); B01D 29/09 (20130101); B30B
9/22 (20130101); B01D 29/822 (20130101); B01D
29/6415 (20130101); B01D 29/52 (20130101); B01D
29/6423 (20130101); B30B 9/24 (20130101) |
Current International
Class: |
B30B
9/02 (20060101); B30B 9/22 (20060101); B30B
9/24 (20060101); B28B 3/00 (20060101); B01D
29/09 (20060101); B28B 7/46 (20060101); B28B
7/40 (20060101); B29c 003/00 () |
Field of
Search: |
;425/406,389,408,84
;100/151,116,118,211 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Spicer, Jr.; Robert L.
Attorney, Agent or Firm: Young & Thompson
Claims
We claim:
1. A press comprising a frame structure including a facing pair of
spaced platens having facing surfaces; a receiving medium for
material to be pressed extending across the facing surface of one
of the platens, a fluid expansible device located between the
platens and including a first flexible diaphragm connected to the
other of the platens and forming a fluid chamber with said other
platen, and an inflatable member between the first diaphragm and
said one platen and comprising a second flexible diaphragm
back-to-back with said first diaphragm and a third flexible
diaphragm for pressing material on the receiving medium, the
inflatable member and fluid chamber being in fluid communication; a
peripheral wall structure located on the receiving medium below the
inflatable member so that a pressing chamber is provided by the
peripheral wall structure, the third diaphragm and the receiving
medium; and inlet means to the expansible device for pressure
fluid.
2. A press as claimed in claim 1, wherein means are provided to
move said inflatable member towards and away from the said one
platen.
3. A press as claimed in claim 2, wherein an intermediate ring
structure is provided between the platens and said inflatable
member is secured to the ring, and means are provided for moving
the ring structure towards or away from said one platen, the
peripheral wall structure being located between the ring structure
and said one platen.
4. A press as claimed in claim 3, wherein the ring structure
includes a shoulder for engagement by the inflatable member whereby
a force is exerted on the shoulder by the inflatable member to
assist in sealing engagement of the peripheral wall structure with
the receiving medium when the wall structure is held against the
receiving medium.
5. A press as claimed in claim 1, wherein the receiving medium is a
filter medium and the third diaphragm has a filter medium thereon,
the filter medium forming an envelope between said third diaphragm
and said one platen.
6. A press as claimed in claim 5, wherein the filter mediums are
endless bands trained around rollers outwith the press and provided
with means for progressing it around the rollers.
7. A press as claimed in claim 6, wherein the progressing means
include a releasable clamp mounted for reciprocal motion and
adapted to grip the cloth on a forward movement to progress the
cloth around the rollers.
8. A press as claimed in claim 7, wherein the progressing means
comprises a pulley system including a reciprocal guide having a
roller system for withdrawal of cloth on an advance movement of the
guide, drive means for reciprocation of the guide, said clamp being
mounted on the guide.
9. A press as claimed in claim 1, wherein the facing surface of
said one platen and the side of the third diaphragm facing said one
platen are grooved for drainage of expressed liquid.
10. A press as claimed in claim 3, wherein the means for moving the
ring relative to said one platen comprise a plurality of
piston-and-cylinder devices which when the press is in operation
press a peripheral wall structure linked with the ring against the
receiving medium.
11. A press as claimed in claim 3, wherein the periphery bounding
the area of contact of the back-to-back diaphragms defines a
greater area than that defined by the outer perimeter of contact of
the ring structure with said one platen.
12. A press as claimed in claim 11, wherein the inner platen
engaging surface of the peripheral wall structure includes a
sealing ring and said periphery bounding the contact area of the
back-to-back diaphragms defines a greater area than that defined by
said sealing ring.
13. A press as claimed in claim 3, wherein an inlet for material to
be pressed is provided through the peripheral wall structure to
permit the pressing chamber to be filled with material to be
pressed when the peripheral wall structure is in position below the
inflatable member, the peripheral wall structure including shifting
means to separate the peripheral wall structure from the receiving
medium upon deflation of the expansible device and retraction of
the ring upon completion of the pressing operation.
14. A press as claimed in claim 13, wherein the shifting means
include apertured lugs attached to the outer periphery of the
peripheral wall structure and engageable by the ring moving
means.
15. A press as claimed in claim 1, wherein the peripheral wall
structure is in the form of a block mould including an inner wall
profiled to produce a block of desired peripheral shape, and the
receiving medium is in the form of a drainage bed including a
moulding station whereat the block mould is located.
16. A press as claimed in claim 15, wherein means are provided to
move the mould to and from the moulding station.
17. A press as claimed in claim 16, wherein means are provided to
fill the mould when the mould is outside the moulding station.
18. A press as claimed in claim 16, wherein the space between the
said platens drainage provides an open-ended passage through the
press and a conveyor belt in the form of a length of open mesh
metal strip is positioned on the drainage bed for support of the
mould, the conveyor belt extending beyond the open-ended passage of
the press and means being provided to move this belt into and out
of the passage.
19. A press as claimed in claim 18, wherein lift means are provided
outside the passage adapted to engage and separate the mould from
the conveyor belt and the pressmoulded material.
20. A press as claimed in claim 19, wherein the lift means comprise
a number of extensible rams which can raise or lower the mould
relative to the conveyor belt.
21. A press comprising a frame structure including a facing pair of
spaced platens having facing surfaces; a receiving medium for
material to be pressed extending across the facing surface of one
of the platens; an intermediate ring between the platens; means for
moving the ring towards or away from the said one platen; a fluid
expansible device partly located between the other of the platens
and the intermediate ring and including a pressing diaphragm
projecting into the aperture of the ring for pressing of material;
inlet means for pressure fluid to the expansible device; the
arrangement of the expansible device and ring being such that a
peripheral shoulder is provided by the ring for the expansible
device whereby on inflation of the expansible device a force is
exerted on the shoulder; a peripheral wall structure arranged such
that a pressing chamber is defined between the said pressing
diaphragm of the expansible device, the receiving medium and the
peripheral wall structure; the introduction of pressure fluid to
the expansible device through the inlet means causing inflation of
the expansible device to press material in the pressing chamber and
to assist in sealing engagement of the peripheral wall structure
with the receiving medium by means of the said force on the ring
shoulder when the wall structure is held against the receiving
medium.
Description
This invention relates to a press and particularly a filter press
for expressing liquids from materials.
According to the present invention there is provided a press
comprising a frame structure including a facing pair of spaced
platens having facing surfaces; a receiving medium for material to
be pressed extending across the facing surface of one of the
platens, a fluid expansible device located between the platens and
including a first flexible diaphragm connected to the other of the
platens and forming a fluid chamber with said other platen, and an
inflatable member between the first diaphragm and said one platen
and comprising a second flexible diaphragm back-to-back with said
first diaphragm and a third flexible diaphragm for pressing
material on the receiving medium, the inflatable member and fluid
chamber being in fluid communication; and inlet means to the
expansible device for pressure fluid.
Embodiments of the present invention will now be described by way
of example with reference to the accompanying drawings in
which:
FIG. 1 shows a side view of a press for forming concrete wall
panels;
FIG. 2 shows a plan view of the press of FIG. 1 together with a
conveyor band passing through the press;
FIG. 3 shows a cross-sectional view of the diaphragm and ring
arrangement between the sections of the press of FIG. 1; and
FIG. 4 shows filter press apparatus including a press of the type
shown in FIG. 1.
Referring to FIGS. 1-3, in one embodiment of the present invention,
a filter press is provided for the press moulding of concrete or
other cementitious blocks for use in construction work, for
example, the erection of buildings.
The press 1 comprises generally a frame which is formed with top 2
and bottom 3 sections, each of which is a hollow metal box
fabrication of girders 4 and plates 5. The two sections 2, 3 are
spaced vertically one above the other, and are supported along two
parallel sides by upstanding columns 6, bolted to the sections 2,
3. Thus an open-ended through passage 7 is defined between the two
spaced sections 2, 3 and the columns 6.
The facing portions 8, 9 of the two sections 2, 3 each comprise a
metal plate. An intermediate metal ring 10 (FIG. 3) is positioned
within the passage 7 and attached to the upper section 2 by means
of a number of pressure fluid operated ram devices 11, whereby the
ring 10 can be moved towards or away from the upper plate 8.
Interposed between the ring 10 and the upper plate 8 are two
back-to-back flexible inflatable diaphragms 12, 13, clamped to the
plate 8 and the ring 10 respectively, by clamping rings 14, the
diaphragms 12, 13 abutting one another but having a centrally
located connection port 15 to provide fluid communication
therebetween. The diaphragm 13 is clamped to the ring 10 around the
outer periphery thereof, so that an inwardly projecting shoulder 18
is provided on the ring 10. The space defined between the upper
plate 8 and the diaphragm 12 attached to that plate 8 is provided
with an inlet pipe 16 leading through the top section 2 for the
supply and discharge of pressure fluid. The connection port 15
between the two diaphragms 12, 13, has a peripheral metal flange 17
on each diaphragm, the two flanges 17 being bolted together.
A third flexible inflatable diaphragm 19 is provided, this one
being clamped to the ring 10 by clamp 14, and arranged, when
inflated, to protrude through the ring gap 20 (FIG. 3) towards the
lower plate 9. A peripheral wall member 21, or mould, having an
appropriately profiled inner peripheral wall 22 is positioned
beneath the ring 10 and is located at a moulding station on a
drainage bed formed by a perforated metal conveyor belt 23 which
rests on the lower metal plate 9. The top surface of the lower
plate 9 is grooved for drainage of any liquids expressed during the
pressing operation which occurs upon inflation of the diaphragms
12, 13, 19, by the admission of pressure fluid.
A pressure chamber 24 is defined by the profiled inside wall 22 of
the mould 21, the perforated belt 23 and the lower surface of the
third diaphragm 19.
The conveyor belt 23 extends out beyond the press passage 7 on both
sides of the press 1 (see FIG. 3), and is in the form of an endless
band entrained around end drums 25, 26, with a drive motor unit 27
provided for progressing the belt 23, so as to move the belt 23
into, through and out of the press chamber 24 in the desired
direction and to the desired extent.
The mould member 21 has a rubber insert sealing member 28 on its
underside, and is held in contact with the conveyor belt 23 and the
bottom section 3 by the action of the rams 11, which space the ring
from the upper metal plate and by the effect of the pressure fluid
inflating the three diaphragms and acting on the shoulder 18. The
grooves (not shown) on the upper surface of the lower metal plate 9
communicate with drainage channels (not shown) running along the
sides of the press 1. Additionally, the ring member 10 has itself a
resilient rubber insert 29 on its underface to facilitate a sealing
engagement within the wall member 21 during the pressing
operation.
Outwith the press passage 7 on either side of the conveyor belt a
plurality of pressure fluid operated rams (not shown) are provided,
these being intended to engage the wall or mould member 21 after it
has been moved out of the press chamber 1 after the press operation
has been effected, to separate the wall or mould member 21 from the
press moulded block which can then be conveyed away to futher
treatment, e.g. storage for curing. Retraction of the rams will
then return the wall or mould member 21 on to the conveyor belt 23,
and a fresh charge of the cementitious material to be pressed can
be filled into the area bounded by the member 21, and the wall
member 21 with cementitious charge material conveyed back into the
press passage 7.
The press can operate alternately to discharge a press formed block
at either side so that whilst one formed block is discharged
another one is being formed within the press.
Also, a pair of filter cloths may be provided between the third
diaphragm 19 and the conveyor belt 23, and forms an envelope, the
wall member 21 being positioned between the filter cloths. The
filter cloths are preferably in the form of endless belts and more
appropriately with the conveyor belt 23.
Referring to FIG. 4, in a second embodiment of the present
invention, apparatus is provided for the expression of liquids from
materials such as slurries so that either the material or the
liquid can be reclaimed. The apparatus includes a press similar to
that of the first embodiment, similar parts being referred to by
the same numerals; however in this case it may be desired to pass
the material to be treated into the pressing chamber 24 (FIG. 3)
within the press itself rather than filling the charge outwith the
press passage 7. Thus in this case suitable inlets 30 are provided
through the wall member 21. These inlets 30 are connected to a
slurry supply pipe 31 by flexible conduits 32. Also, the lower
plate 9 which is plane carries a ribbed rubber block 33 for
drainage of the filtrate; and a pair of endless filter cloth bands
34, 35 form an envelope between the third diaphragm 19 and the
rubber block 33, the pressure chamber 23 being defined by the
inside wall 22 and the two filter cloths 34, 35. The undersurface
of the third diaphragm 19 is grooved for drainage of liquids
expressed during the pressing operation. The wall member 21 which
is positioned between the filter cloths 34, 35 is provided with
side apertured lugs 36, through which respective rams 37 of the
devices 11 project, the heads of each of these rams 37 being in the
form of a stirrup 38 for engagement with the lugs 36, whereby,
after the pressing operation has been effected, and upon deflation
of the diaphragms 12, 13, 19, and retraction of the ring towards
the upper plate 7, the wall member 21 will automatically be lifted
out of contact with the lower filter cloth 35 to permit this cloth
with the caked solids on it to be conveyed away out of the press
passage 7. Also, the retraction of the ring 10 causes sufficient
relative displacement between the ring and the wall member 21 to
enable the upper filter cloth 34 to move out of the press passage
7.
Each of the endless filter cloth bands 34, 35, which are trained
around a plurality of rollers 39, has ancillary equipment
associated therewith, this ancillary equipment and rollers 39 being
mounted on an upstanding support structure 40 together with the
press 1. The ancillary equipment includes a pulley drive for the
bands 34, 35 comprising a vertically reciprocal guide member 41
having a pair of opposed rollers 39 around which are trained
oppositely extending lengths of filter cloth, a piston-and-cylinder
actuator 41A for the member 41 and a clamp 46 for the cloth to
permit progressive movements of the cloth; a brushing device 42 for
removal of excess slurry from the band and a discharge chute 43
located below the device 42; an additional cloth washing assembly
44; and a controller 45 for regulating each advance of the endless
cloth position. Pipelines 47, 48 are located to receive filtrate
passing from the diaphragm 19, the ring 10 including apertures in
its peripheral wall for fluid communication between the grooves in
the bottom surface of the diaphragm 19 and the pipelines 47, and
from the ribbed block 33 respectively, and may discharge the
filtrate to a suitable receiver (not shown).
In operation of the filter press apparatus, the ram devices 11 are
actuated to move the ring 10 downwards, and the diaphragm assembly
12, 13, 19 is given a preliminary pressurisation, this pressure
being determined by the capacity of the pump delivering slurry to
the press 1 and by the required filtration pressure. A charge of
slurry is delivered through the inlets 30 from pipe 31 and between
the filter cloths 34, 35. The diaphragm assembly 12, 13, 19 is
fully pressurised, and filtration occurs through the filter cloths
34, 35; the wall member 21 is maintained in sealing engagement with
the lower cloth 35 by the downward action of the ram devices 11 and
by the pressure of fluid acting on the shoulder 18 of the ring 10.
The filtrate passes via the grooves in the diaphragm 19 and block
33 to the pipelines 47, 48, whence it is discharged. After
filtration, the diaphragm assembly is deflated, and the ram devices
11 operate to move the wall member 21 clear of the bottom cloth 35
and so that the cloths 34, 35 can be moved through the passage 7.
The cloth bands 34, 35 are advanced to bring clean portions of
cloth into the passage 7, the pressed cake being simultaneously
removed from the press by the lower moving bank 35. Prior to moving
of the bands 34, 35, the grooves may be cleaned by the passage of
air or cleaning fluid thereto through the pipelines 47, 48.
It may be desirable to surround the wall member 21 in a stretch
nylon material sock to facilitate separation of it from the pressed
material, particularly in the case of the press for moulding
cementitious blocks. Conveniently this sock material could be a
suitable length of material which is doubled over the wall member
and has its edges tied together outside the wall member.
In a typical example, the diaphragms can be inflated by water
pressurised up to approximately 450 p.s.i., or if pressure air is
to be used, then this would be of up to a pressure of about 150
p.s.i.
The above press has the following advantages:
i. The top and bottom sections 2, 3 are fixed: in previous presses
these sections were movable to permit removal of the pressed
material and additional guiding and lifting apparatus was
consequently required.
ii. The diaphragm assembly 12, 13, 19 occupies the space between
the sections 2 and 3, and is arranged, i.e. by the provision of the
shoulder 18, to assist in maintaining a seal between the ring 10
and the wall member 21, and between the wall member 21 and the
lower section 3.
iii. The diaphragms 12, 13 by their back-to-back arrangement are
"free standing" and can contain the internal pressure on their own;
the lower diaphragm 19 is supported by the material to be pressed
and consequently does not require to be "free standing". Rupture in
the diaphragm is consequently mitigated. Also, the present
diaphragm arrangement dispenses with a peripheral connection
between the diaphragms, which connection was subject to
failure.
iv. There is no friction between the diaphragms 12, 13 and the
plates 7, 8.
* * * * *