Abstrict
A method is provided for fixedly joining a cloth, a cloth-like
fabric or a synthetic mesh to a filter plate using a flanged cloth
connector ring. The flanged cloth connector ring is attached to
the filter cloth around the feed port of the cloth and inserted
into a receiving channel in the filter plate. A locking ring or
a distribution ring may be inserted into the channel adjacent to
the connector ring to retain the connector ring and attached filter
cloth in place. Filter cloths may be individually and independently
attached to each side of a filter plate using a cloth connector
ring.
Claims
I claim:
1. A connector for attaching a filter cloth to a filter plate in
a filter press, comprising: collar portion configured to couple
to the perimeter of a central opening on the filter cloth, said
collar portion having a substantially flat surface configured to
abut a first side of the filter plate; and a tab portion extending
at an angle relative to the collar portion configured to engage
a recess in the filter plate, wherein the tab portion includes a
radially outer surface that is inclined at an obtuse angle relative
to the flat surface of said collar portion and wherein the radially
outer surface is configured to abut an inclined surface of the filter
plate, and a tab clip extending radially outwardly from the radially
outer surface of said tab portion for engaging a bore of the filter
plate.
2. The connector of claim 1, further comprising serrations on a
radially inner surface of the tab portion.
3. The connector of claim 1, further comprising a lock ring for
securing the tab portion in the recess.
4. The connector of claim 1, wherein the tab portion extends substantially
perpendicular to the collar portion.
5. The connector of claim 1, wherein the collar portion and tab
portion are formed of a material selected from the group consisting
of rubber, plastic and mixtures thereof.
6. The connector of claim 1, wherein the collar portion forms an
annular ring having a hole corresponding to a hole of the filter
cloth.
7. The connector of claim 1, wherein the tab clip includes a first
surface extending perpendicular to the tab portion, a second surface
extending parallel to a longitudinal axis of the connector and a
third and forth surface extending at an angle relative to the longitudinal
axis, wherein the third and fourth surface intersect at to form
a point at an end of the connector.
8. The connector of claim 1, wherein the collar portion is attached
to a central opening of a filter cloth.
9. The connector of claim 1, wherein the collar portion forms an
annular opening that is larger than an opening of a filter plate
to which the connector is attached.
10. A connector for attaching a filter cloth to a filter plate
in a filter press, comprising: a collar portion configured to couple
to the perimeter of a central opening on the filter cloth; a tab
portion extending at an angle relative to the collar portion configured
to engage a recess in the filter plate; and a tab clip extending
from the tab portion for engaging a bore of the filter plate, wherein
the tab clip includes a first surface extending perpendicular to
the tab portion, a second surface extending parallel to a longitudinal
axis of the connector and a third and fourth surface extending at
an angle relative to the longitudinal axis, wherein the third and
fourth surface intersect at to form a point at an end of the connector.
11. The connector of claim 10, further comprising serrations on
a radially inner surface of the tab portion.
12. The connector of claim 10, further comprising a lock ring for
securing the tab portion in the recess.
13. The connector of claim 10, wherein the tab portion extends
substantially perpendicular to the collar portion.
14. The connector of claim 10, wherein the collar portion and tab
portion are formed of a material selected from the group consisting
of rubber, plastic and mixtures thereof.
15. The connector of claim 10, wherein the collar portion forms
an annular ring having a hole corresponding to a hole of the filter
cloth.
16. The connector of claim 10, wherein the tab portion includes
a radially outer surface that is inclined relative to a longitudinal
axis of the connector and wherein the outer surface is configured
to abut an inclined surface of the filter plate.
17. The connector of claim 10, wherein the collar portion has a
substantially flat surface extending perpendicular to a longitudinal
axis, which is configured to abut a first side of filter plate.
18. The connector of claim 10, wherein the collar portion is attached
to a central opening of a filter cloth.
Description FIELD OF THE INVENTION
The present invention relates to a filter plate in a filter press
for separating solids and liquids. More particularly, the present
invention relates to a system and method for attaching a filter
media to a filter plate.
BACKGROUND OF THE INVENTION
A filter press is an economic and efficient liquid/solid separation
device commonly utilized in the clay, chemical, or mining industries.
Filter presses generally employ a plurality of filter plates, each
filter plate having large areas of a textile material to form a
filtering screen. The textile material is typically attached to
a cloth, rubber or plastic tubular hub. The tubular hub allows the
material to be filtered to pass through successive filtering chambers
in the press. The tubular hub must be securely attached to the filtering
material to prevent leakage, and is usually constructed of a textile
tube or a thermoplastic or rubber material.
In the current state of the art, filter cloth is generally installed
on the filter plates by rolling up one side of a duplex filter cloth,
which is joined at a feed hole with the tubular hub, and then pushing
the rolled up filter cloth through the feed hole of the filter plate.
After passing the rolled cloth through the feed hole, the filter
cloth is then unrolled. The filter plate thus has a layer of filter
cloth on either side thereof, and the two filter cloth layers are
fastened together on the filter plate. Slurry is pumped into the
filter press and fills each cavity within the stack of filter plates.
Solids remain in the chambers and filtrate passes through the cloth,
exiting the filter plate.
Conventional methods for joining the filtering material to the
tubular hub include sewing the two filter cloth layers together.
This approach is labor intensive and thus expensive. Moreover, the
sewing tends to create weaknesses in the joint due to the stitch
holes. Stitching can also be difficult due to the thickness of the
filter cloth and the tubular hub. Other methods include adhesive
and bonding agents to secure the filtering cloth to the tubular
hub, but these techniques are time consuming since the adhesive
must set to form the bond, and is not consistently reliable. Welding
requires a split clamping collar positioned between the flanges
of the feed neck to transmit force to the weld from a clamping cylinder.
U.S. Pat. No. 4,765,859 describes a method of joining filter cloth
to a rubber tubular hub for use as a filter screen, which is installed
on a filtering plate in a filtering press. The hub consists of a
cylindrical tube that includes two annular flanges protruding radially
outward from the circumference of the tube at each end. The tubular
hub is fabricated from a rubber material that is collapsible. A
filtering screen is then constructed by joining two filter cloths
to the hub at each end of the tube. One filter cloth is joined to
the hub at the inside surface of one flange, while the other filter
cloth is joined to the inside surface of the other flange. The filter
cloth and hub are bonded together by induction heating to form a
seal to prevent leakage of the filtered material.
U.S. Pat. No. 5,958,173, the contents of which are herein incorporated
by reference, describes a method of fabricating a filter screen
for a filter press by attaching a filter cloth to a tubular hub
using induction heating.
The methods in the prior art of attaching a filter cloth to a filter
plate pose a number of disadvantages. The prior methods of installing
filter cloth are difficult and time consuming, particularly for
larger filters (up to 2 meters by 2 meters square). The large cloth
requires a person on each side of the filter plate: one person to
push the filter cloth through the hole, and the other person to
receive the filter cloth. Large presses are usually re-clothed without
removing plates, requiring operators to get between the plates physically,
sometimes on platforms above conveyors or high above the ground
level, a procedure that can be dangerous. The removal of filter
plates in order to replace the filter cloths causes significant
losses in productivity, as the filter press cannot be used during
the replacement process.
Furthermore, the duplex-type of filter cloths used in the prior
art can be expensive, as both layers of a duplex filter cloth must
be removed and replaced when a hole forms in only one of the layers.
The process of assembling the duplex filter cloths on a flanged
tube for attachment to a filter plate is also complex and unwieldy.
It is thus desirable to find a new method for securely joining
a filtering material such as a cloth fabric or synthetic material,
as commonly used in filtering applications, to a filter plate.
SUMMARY OF THE INVENTION
The present invention addresses the need for an efficient and effective
method for attaching a filter cloth to a filter plate installed
in a filter press. In an illustrative embodiment of the present
invention, a flanged cloth connector ring is fastened about the
inner edge of a central feed port in a filter cloth to attach the
filter cloth to a filter plate. The connector ring may include a
collar portion and a flanged tab portion extending substantially
perpendicular to the collar portion. The filter cloth is attached
to the connector ring at the collar portion. The flanged tab portion
includes a tab clip on an outer surface thereof configured to interface
with a slot or bore in the filter plate body, thereby connecting
the filter cloth to a first side of the filter plate. A locking
ring or a distribution ring may be used to retain the connector
ring and lock the tab clip into the filter plate body. Serrations
may be provided on an inner surface of the tab portion of the connector
ring to hold the lock ring or distribution ring in place by friction
fit.
An assembled filter plate may comprise a pair of filter cloths,
which are individually attached to each side of the plate using
the cloth connector ring and a locking or distribution ring.
According to one aspect of the invention, a connector for attaching
a filter cloth to a filter plate in a filter press is provided.
The connector comprises a collar portion configured to couple to
the perimeter of a central opening on the filter cloth and a tab
portion extending at an angle relative to the collar portion configured
to engage a recess in the filter plate.
According to another aspect of the invention, a method of assembling
a filter plate is provided. The method comprises attaching a first
filter cloth comprising a filter media and a central opening to
a connector ring. The connector ring comprises a collar portion
and a tab portion extending perpendicular to the collar portion.
The first filter cloth is connected to the connector ring at the
collar portion. The method also comprises the step of engaging the
tab portion of the connector ring with a recess in the filter plate.
The filter plate includes a feed port for providing a slurry to
be filtered.
According to another aspect of the invention a filter plate comprising
a frame having a feed port and a first annular bore, a first filter
cloth secured to a first side of the frame and a first flanged connector
ring for securing the first filter cloth to the frame is provided.
The first annular bore is configured to receive a portion of the
first flanged connector ring to secure the first filter cloth to
the frame.
According to yet another aspect of the invention a filter plate
for supporting a filter cloth is provided. The filter plate comprises
a frame and a feed port formed in the frame having an inner surface
configured to receive a flanged connector ring for securing a filter
cloth to the frame at the central feed port.
According to still another aspect of the invention a filter plate
comprising a frame for supporting a filter cloth, a feed port formed
in the frame and an undercut bore in the frame is provided. The
undercut bore extends in a radial direction for receiving a flange
of a connector ring to secure a filter cloth to the filter plate.
In another aspect of the invention, filter cloth is provided. The
filter cloth comprises a liquid permeable filtering media for separating
solids from the liquids in a slurry and a connector ring. The filtering
media has a feed hole formed therein for allowing passage of the
slurry through the filter cloth. The connector ring is attached
to an edge of the feed hole for connecting the filtering media to
a filter plate.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other objects, features and advantages of the
invention will be apparent from the following description and from
the accompanying drawings, in which like reference characters refer
to the same parts throughout the different views. The drawings illustrate
principles of the invention and, although not to scale, show relative
dimensions.
FIG. 1 illustrates a filter press suitable for implementing an
illustrative embodiment of the invention.
FIG. 2 is a cross sectional view of a filter plate stack of the
filter press of FIG. 1.
FIG. 3 shows a filter plate in the filter press of FIG. 1, in accordance
with an illustrative embodiment of the present invention.
FIG. 4 is a cross sectional view of a central portion of an assembled
filter plate according to an illustrative embodiment of the invention.
FIG. 5 is a top view of the portion of the filter plate shown in
FIG. 4.
FIG. 6 is an exploded cross-sectional view of the portion of the
filter plate of FIG. 4.
FIG. 7 is a detailed cross-sectional view of the cloth seal connector
ring of FIG. 4.
FIG. 8 is a cross sectional view of a central portion of an assembled
filter plate according to another embodiment of the invention.
FIG. 9 is a top view of the portion of the filter plate shown in
FIG. 8.
FIG. 10 is an exploded cross-sectional view of the portion of the
filter plate of FIG. 8.
FIG. 11 is a cross-sectional view of a central portion of an assembled
filter plate stack according to another embodiment of the invention,
including a plurality of distribution rings.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
In the illustrative embodiments, the present invention provides
an improved system and method for attaching one or more filter cloths
to a filter plate in a filter press. The illustrative system includes
a cloth connector ring, which connects a filter cloth with a filter
plate. The cloth connector ring facilitates assembly of a filter
plate, is designed for manufacturability, is low in cost and provides
improved efficiency and productivity of a filter press implementing
the cloth connector ring to attach a filter cloth to a filter plate.
The present invention will be described below relative to illustrative
embodiments. Those skilled in the art will appreciate that the present
invention may be implemented in a number of different applications
and embodiments and is not specifically limited in its application
to the particular embodiments depicted herein.
FIG. 1 illustrates a filter press 10 suitable for implementing
an illustrative embodiment of the invention. The illustrative filter
press 10 is a batch filtering machine comprising plurality of filter
plates 20 clamped together and sealed against each other on the
wedge sides to form a filter plate stack 12. The filter plates form
filter chambers 21 between each other. The filter plates support
and are covered by filter cloths to form multiple cavities between
the plates for collecting solids. The filter press 10 includes a
feed head 18 at a first end of the machine containing piping for
delivering a slurry to be filtered. As used herein, "slurry"
refers to a mixture of liquid and solids that is introduced to a
filter press for separation. At a second end of the filter press
10 is a crosshead 14 containing a clamping mechanism. A moving plate
16, known in the art as a "tail plate", clamps the filter
plate pack. During a filtering operation, slurry is pumped into
filter chambers formed by the stacked filter plates and filter cloths,
and is pushed against a filter cloth on a proximate filter plate.
Liquid (filtrate) from the slurry passes through the filter cloth
and exits through filtrate ports in a filter plate. Solids from
the slurry collect on the surface of the filter cloth within the
chamber until the chamber is full, which forms a filter cake. The
filter cake may be washed or blown dry, if necessary. The collected
filter cakes are discharged, completing the filtration cycle.
FIG. 2 is a cross-sectional view of a filter plate stack 12 of
the filter press of FIG. 1, which comprises a plurality of filter
plates 20 stacked together. An embodiment of an individual filter
plate 20 is shown in FIG. 3. As shown, each filter plate 20 may
comprise a frame 23 with a first layer or sheet of filtering cloth
22 and a second layer or sheet of filtering cloth 24 sealably joined
to opposite sides of the frame 23. The filtering cloths 22, 24 form
cavities or chambers 21 between the filter plates 20 for retaining
solids between the filtering cloths 22, 24 when two or more filter
plates 20 are stacked together. A slurry feed port 40 is formed
in the center of the filter plate 20 for delivering a slurry to
be filtered. Filtrate ports 25 may be provided at the edges of the
frame 23 for receiving and transferring filtrate from the filter
plate 20. In the illustrative embodiment, stay bosses 26, or other
suitable stabilization devices, may be provided around the central
feed port 40 to help stabilize the filtrate plate 20. One skilled
in the art will recognize that the invention is not limited to the
illustrated filter plate stack or filter plate configuration, and
that the filter plate stack and filter plate may have any suitable
configuration for filtering a slurry.
The filter cloths 22 and 24 may be fabricated from a natural or
man-made material or any combination thereof, which is acceptable
for filtering applications. Suitable fabrics for forming the filter
cloths 22, 24 include, but are not limited to natural fibers, such
as cotton, or plastic fibers, such as polypropylene or nylon, for
retaining cake solids. One skilled in the art will recognize that
any suitable material for filtering a slurry may be used.
During a filtering process, a filter cloth 22 or 24 covers each
side of the filter plate 20. As the slurry is pumped into the plate
stack 12, the filter cloths retain the solids and allow the filtrate
to pass through, completing the separation process. The filter cloths
22, 24 are fastened together and attached at an outside edge 27
formed in the perimeter of the plate 20. Any suitable means known
in the art may be used to form the peripheral seal, including, but
not limited to Velcro, ties, o-rings, a rope hammered into a groove
extending along the perimeter, and so on. The filter cloths 22,
24 are sealingly connected to each side of the filter plate 20 at
the feed position 40, which receives a pumped slurry under pressure
to fill the filter chamber 21.
According to an illustrative embodiment of the invention, each
filter cloths 22 or 24 is connected to a side of a filter plate
using a cloth connector ring. According to the illustrative embodiment,
the filter plate includes a surface having a recess or other feature
configured to receive and retain a cloth connector ring for attaching
a filter cloth to the filter plate. For example, as described with
respect to FIGS. 4-11, a flanged connector ring 42, 44, 92, 94,
212 or 214 may be used to sealingly connect a filter cloth to a
filter plate at a feed position 40 of the filter plate. According
to the illustrative embodiment, the feed position 40 is located
in the center of the plate. One skilled in the art will recognize
that the feed position, and thus the attachment point of the filter
cloths 22, 24 may alternatively be located in a corner or location
offset from the center of the filter plate 20.
FIG. 4 is a cross sectional side view of an assembled filter plate
20 at the point of attachment of the filter cloths 22, 24 according
to an illustrative embodiment of the invention. FIG. 5 is a detailed
top view of the region of the filter plate 20 where a filter cloth
22 is attached to the filter plate. FIG. 6 is an exploded cross-sectional
view of the components of the filter plate shown in FIG. 4. In the
illustrative embodiment, each filter cloth 22, 24 includes a feed
hole 52, 54, respectively, corresponding to the slurry feed port
40 of the filter plate. In the illustrative embodiment, a feed hole
is located in the central portion of the filter cloth, though one
skilled in the art will recognize that the feed hole and feed ports
may be located in any suitable position. A first cloth connector
ring 42 is connected to the first filter cloth 22 around the perimeter
of the feed hole 52 for attaching to first filter cloth 22 to a
first side of the filter plate 20. A second cloth connector ring
44 is connected to the second filter cloth 24 around the perimeter
of the feed hole 54 for attaching the second filter cloth 24 to
a second side of the filter plate 20. According to the illustrative
embodiment, the cloth connector rings 42, 44 may be connected to
the corresponding filter cloth by sewing, welding or mechanically
coupling an inner edge of the filter cloth, defined by the central
hole 52 or 54, to the corresponding connector ring 42 or 44 through
means known in the art. One skilled in the art will recognize that
any suitable means for connecting a connector ring to a filter cloth
may be used in accordance with the teachings of the invention.
According to an illustrative embodiment, as shown in FIGS. 4-7,
the slurry feed port 40 of the filter plate 20 is configured to
receive and retain a cloth connector ring 42 or 44. As shown, a
filter cloth 22 or 24 may be attached to a side of the filter plate
20 by inserting an associated cloth connector ring 42 or 44 in the
feed port 40, such that the inner surface of the feed port 40 receives
and retains the cloth connector ring, thereby attaching a filter
cloth associated with the cloth connector ring to the filter plate.
According to the illustrative embodiment, the cloth connector rings
are configured to be received and retained by the inner surface
of the central slurry feed port. For example, the cloth connector
rings may have an outer surface that is complementary to the inner
surface of the central slurry feed port. One skilled in the art
will recognize that the filter plate 20 and the cloth connector
rings may have any suitable configuration for coupling the cloth
connector ring to the filter plate, and that the invention is not
limited to the illustrated configuration.
In the embodiment shown in FIGS. 4 and 6, the slurry feed port
40 of the illustrative filter plate 20 includes recesses or grooves,
illustrated as first and second undercut counter bores 46, 47 or
slots cut into the filter plate on the inner surface of the port
40. In the illustrative embodiment, the bores 46, 47 extend in a
radial direction, perpendicular to the longitudinal axis -A- of
the filter plate 20. The first undercut counter bore 46 receives
the first cloth connector ring 42 attached to the first filter cloth
22 and the second undercut counter bore 47 receives the second cloth
connector ring 44 attached to the second filter cloth 24. The inner
surface of the central feed port 40 also includes a first inclined
surface 466 extending from the first side of the filter plate inward
to the first bore 46 at an incline relative to the longitudinal
axis -A- and a second inclined surface 467 extending from the second
side of the filter plate 20 inward toward the second bore 47. One
skilled in the art will recognize that the surfaces 466 and 467
may alternatively extend parallel to the axis -A-. An annular central
protrusion 468 extends around the inner surface of the feed port
40 between the bores 46, 47. The annular central protrusion 468
is defined by walls 46c and 47c of the bores 46 and 47, respectively,
and an axially extending surface 468a having a reduced diameter
relative to the bores 46 and 47 and the surfaces 466 and 467.
Locking rings 62, 64 may also be provided for locking the cloth
seal ring connector rings 42, 44, respectively in place after insertion,
thereby locking the filter cloths 22, 24 to the filter plate 20.
FIG. 7 illustrates an embodiment of a cloth connector ring 42 in
detail, though one skilled in the art will recognize that the cloth
connector ring 42 may have any suitable configuration for coupling
to the filter plate 20 to attach a filter cloth to thereto. As shown
in FIG. 7, the illustrative cloth connector ring has a configuration
that is complementary in shape to the feed port inner surface, comprised
of surfaces 466, 467, 468a and bores 46 and 47. As shown, the cloth
connector ring 42 comprise a flat, preferably annular, collar portion
421 attaching the cloth connector ring to a filter cloth. The collar
portion 421 is configured to abut a first side of the filter plate
in the vicinity of the feed port 40, as shown in FIG. 4.
The cloth connector ring 42 further includes a flanged tab clip
portion 422 extending inward and substantially perpendicular to
the collar portion 421. The flanged tab portion 422 is configured
to abut the inner surface of the central feed port 40 to secure
the cloth seal connector ring 42, and thus a connected filter cloth,
to the filter plate. The tab portion 422 terminates in an axially
outward extending tab clip 424, which is received by the bore 46
of the filter plate to secure the connector ring 42 to the filter
plate. The illustrative tab clip flange 424 includes a first surface
424a configured to abut a radially extending wall 46a of the bore
and a second surface 424b configured to abut a longitudinally extending
wall 46b of the bore. A third wall 424c and a fourth wall 424d of
the flange 424 extend at inclines relative to the longitudinal axis
and converge at an end, illustrated as a point 424e forming the
end of the connector ring 42. The point 424e abuts a second axially
extending wall 46c, which terminates in the protrusion 468. Alternatively,
the third wall 424c and fourth wall 424d may form a flat end configured
to abut, and lie flat against, the central protrusion 468. One skilled
in the art will recognize that the tab portion 422 may have any
suitable configuration for cooperating with a surface of the filter
plate to attach the connector ring to the filter plate.
The illustrative tab portion 422 may further include serrations
423 on an inner face 425 of the tab portion 422, opposite the surfaces
that interact with the feed port inner surface. The serrations 423
enhance the friction fit between the connector ring and a corresponding
locking ring 62 or a distribution ring (described below). As shown,
the tab portion outer surface 426 matches the inclined surface 466
of the slurry feed port 40 of the filter plate and is configured
to abut against the inclined surface 466. As shown, the tab portion
outer surface at an obtuse angle relative to a substantially flat
surface of the collar abutting the side of the filter plate and
is also inclined surface 466. The tab portion outer surface 426
abuts the inclined surface 466 of the slurry feed port 40 when the
filter plate is assembled to securely and sealingly connect the
filter cloth 22 to the filter plate 20. One skilled in the art will
recognize that the tab portion outer surface 426 and the inner surface
466 of the slurry feed port may have any suitable configuration.
According to a preferred embodiment, the tab portion outer surface
426 and the inner surface 466 of the slurry feed port have complementary
shapes to facilitate attachment of the cloth connector ring to the
filter plate.
According to the illustrative embodiment, the second cloth connector
ring 44 of FIGS. 4-6 is configured similar to the first cloth connector
ring 42, though one skilled in the art will recognize that the cloth
connector rings 42 and 44 may have different configurations. One
skilled in the art will recognize that the tab portions and cloth
connector rings are not limited to the illustrative configuration
and that any suitable configuration for sealingly connecting the
filter cloth to the filter plate may be used in accordance with
the invention.
The cloth connector ring 42, 44 may be manufactured from rubber,
thermoplastic rubber, plastic, cloth or any other suitable material
and may be formed by machining, molding or any other suitable process.
To assemble the filter plate 20 of FIGS. 4-6 using a cloth connector
ring having a configuration shown in FIG. 7, a first filter cloth
22 is connected to a first cloth connector ring 42 and aligned with
the filter plate, such that the feed port 52 of the filter cloth
22 aligns with the feed port 40 of the filter plate 20. The tab
portion 422 of the connector ring is pushed into the feed port 40,
such that the tab clip 424 engages the bore 46 and the inclined
outer surface 426 abuts the inclined inner surface 466 of the filter
plate. Next, the locking ring 62 is pushed into position in the
central feed port 40 to lock the tab clip flange 424 into the bore
46 on the filter plate body. The locking ring is pushed until the
end of the locking ring abuts the protrusion 468 and the outer surface
of the locking ring abuts the inner surface of the tab portion.
The locking ring 62 is stopped by the protrusion ring 468 and held
in place by friction fit with the serrations 423 and the protrusion
ring 468. The outer edges of the filter cloth are then attached
to the outer edges of the filter plate frame through means known
in the art, as described above. The second filter cloth 24 is attached
to the second side of the filter plate 20 in a similar manner, using
the second cloth connector ring 44 and second locking ring 64.
According to another embodiment of the invention, the recesses
receiving the connector rings for attaching a filter cloth to a
filter plate comprise slots. For example, as shown in FIGS. 8-10,
a filter plate 70 includes a first slot 86 for attaching a first
filter cloth 72 to a first side of the filter plate 70 using a first
cloth connector ring 92 and a second slot 88 for attaching a second
filter cloth 74 to a second side of the filter plate 70 using a
second cloth connector ring 94. As shown, in the second embodiment,
the central feed port 90 has a straight inner surface 91. The first
slot 86, which preferably comprises an annular undercut groove,
is spaced axially outwardly from and surrounding the central feed
port 90 and is cut into the first side of the filter plate for receiving
the first connector ring 92 and first lock ring 96 in order to fasten
the first filter cloth 72 to the filter plate 70. A second slot
88, preferably an annular undercut groove aligned with the first
circular undercut slot and spaced axially outwardly from and surrounding
the central feed port 90, is cut into the second side of the filter
plate for receiving the second connector ring 94 and second lock
ring 98 in order to fasten the second filter cloth 74 to the filter
plate 70.
According to the illustrative embodiment, the filter cloths 72,
74 and connector rings 92, 94 of FIGS. 8-10 are substantially identical
to the filter cloths 22, 24 and connector rings 42, 44 of FIGS.
4-7. However, in the embodiment of FIGS. 8-10, the diameters of
the feed holes 82, 84 of the filter cloths and connector rings is
larger than the diameter of the central feed port 90, rather than
the same as the diameter of the central feed hole, as shown in the
embodiment of FIGS. 4-7. In the embodiment of FIGS. 8-10, the diameter
of the connector rings and filter cloths are configured to allow
insertion of the tab portions 922, 942 of the connector rings 92,
94 in the slots 86, 88 of the filter plate.
As shown, each slot 86, 88 is spaced from the feed port 90 and
includes a main portion 861, 881, respectively, extending substantially
parallel to the longitudinal axis. The main portions 861, 881 have
an inclined wall 861a, 881a, respectively, configured to abut the
inclined wall 866, 868 of the corresponding tab portion 922, 942,
respectively and a longitudinally extending wall 861b, 881b. Each
slot further includes a radially extending recess 926, 928, respectively
for receiving the flange 924, 925 of the tab portion on the connector
ring.
To assemble the filter plate 70 of FIGS. 8-10, the first filter
cloth 72 is connected to the associated cloth connector ring 92
and aligned with the filter plate such that the feed port of the
filter cloth aligns with the feed port of the filter plate. The
tab portion 922 of the connector ring is pushed into the circular
slot 86, such that the flange 924 engages the radially extending
recess 926 and the inclined inner surface 866 abuts the inclined
inner surface 861a of the filter plate. Next, the locking ring 62
is inserted into the slot 86 between the tab portion 922 and the
longitudinally extending wall 861b and pushed into position to lock
the tab clip flange 924 into the bore 46 on the filter plate body.
The locking ring 96 is pushed until the end of the locking ring
abuts the radially extending wall of the recess 926. The serrations
on the surface of the connector ring hold the locking ring in place
by friction fit. The second filter cloth 74 is attached to the second
side of the filter plate 70 in a similar manner, using the second
cloth connector ring 94 and second locking ring 98.
According to yet another embodiment of the invention, shown in
FIG. 11, a filter plate pack 100 includes one or more distribution
rings 110 in place of the lock ring to secure the cloth connector
rings and filter cloths to the filter plate frame. Distribution
rings are known in the art and are used in filter presses to support
the filter plate at the feed port to prevent overflexing the plate
during the feed cycle, caused by pressure differentials. The distribution
rings 110 ensure that the plates are stacked evenly to enhance the
filtering process. Each distribution ring contacts a distribution
ring on an adjoining plate to form a continuous support along the
length of a filter plate pack. Slurry enters a filter chamber 120
between the filter plates via peripheral slots formed or machined
into the circumference of the distribution rings faces.
As shown in FIG. 11, each filter plate 200 has a pair of filter
cloths 202, 204 attached to either side of the filter plate via
connector rings 212, 214. The connector rings are attached to the
filter cloths at the central opening of each feed cloth, though
one skilled in the art will recognize that the connector rings may
be attached to any suitable location on the filter plate using any
suitable connection means. In the illustrative embodiment, the connector
rings 212, 214 engage counter bores 146, 147 in the inner surface
of the central feed port 190 of the filter plate, as described above
with respect to the embodiments shown in FIGS. 4-7, though one skilled
in the art will recognize that the invention is not limited to the
illustrated embodiment. A distribution ring 110 is pushed into position
and held by a press fit and friction of the tab serrations on the
tab portion of the connector rings 212, 214. By the action of clamping
the filter press, the distribution rings 110 are correctly seated
without contacting the bottom of the counter bores 146, 147 of the
filter plate. When the filter is clamped, a positive seal is created
between the distribution ring and the cloth connector ring. The
filter plate 200 of FIG. 11 is substantially identical to filter
plate of FIGS. 4-7, however, the counter bores 146, 147 of the plate
200 may be wider than the bores 46, 47 of the plate 20 to prevent
the distribution rings 110 from contacting the wall of the protrusion
1468 in filter plate 200.
In addition to facilitating installation of the filter cloths 202,
204 on a filter plate 200, the embodiment of FIG. 11 facilitates
installation of the distribution rings 110 in the filter stack 100.
Prior distribution rings are generally awkward to install and are
required to be screwed together. The present invention allows manual
installing without difficulty. The distribution rings can be inserted
into the feed ports by hand and are held in place by friction fit.
The illustrative systems and methods for attaching filter cloths
to a filter plate using a flanged cloth connector ring provides
significant advantages over the prior art. The present invention
allows a pair of filter cloths to be individually and independently
installed on opposite side of a filter without requiring the filter
cloths to be attached to each other. In this manner, one filter
cloth can be removed and replaced without having to remove and replace
the associated filter cloth, resulting in significant cost savings.
The illustrative system is simple to manufacture and provides easy
and fast installation of a filter cloth on a filter plate. Furthermore,
the illustrative filter plate assembly allows for a central feed
design, which has enhanced feed delivery over a corner feed design.
It is thus seen that the invention efficiently attains the objects
set forth above, among those made apparent from the preceding description.
Since certain changes may be made in the above constructions without
departing from the scope of the invention, it is intended that all
matter contained in the above description or shown in the accompanying
drawings be interpreted as illustrative and not in a limiting sense.
It is also to be understood that the following claims are to cover
all generic and specific features of the invention described herein,
and all statements of the scope of the invention which, as a matter
of language, might be said to fall therebetween. |