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WO1998016293A9 - Oscillating shower for disc filter - Google Patents

Oscillating shower for disc filter

Info

Publication number
WO1998016293A9
WO1998016293A9 PCT/US1997/018751 US9718751W WO9816293A9 WO 1998016293 A9 WO1998016293 A9 WO 1998016293A9 US 9718751 W US9718751 W US 9718751W WO 9816293 A9 WO9816293 A9 WO 9816293A9
Authority
WO
WIPO (PCT)
Prior art keywords
disc
filter
oscillating shower
oscillating
shower
Prior art date
Application number
PCT/US1997/018751
Other languages
French (fr)
Other versions
WO1998016293A1 (en
Filing date
Publication date
Application filed filed Critical
Priority to CA002268781A priority Critical patent/CA2268781A1/en
Priority to AU51466/98A priority patent/AU5146698A/en
Publication of WO1998016293A1 publication Critical patent/WO1998016293A1/en
Publication of WO1998016293A9 publication Critical patent/WO1998016293A9/en
Priority to SE9901346A priority patent/SE518835C2/en
Priority to FI990840A priority patent/FI990840A/en

Links

Definitions

  • the invention relates generally to an agitator used in a disc filter and in particular to an eductor agitator that is driven by the input slurry.
  • Disc filters for separating solid particles from liquid are known in the art.
  • the disc filter includes a plurality of hollow discs 2 having side walls 3 of a filter material.
  • the hollow discs 2 are
  • the discs 2 are positioned within a
  • container 5 which has an inlet 6 (shown in FIGURE 2) for introducing a slurry of
  • a vacuum pump 7 draws the
  • the container 5 is filled approximately half way with the slurry. Sections of the disc 2 rotate counter-clockwise, enter the slurry and
  • a scraper 1 is used to remove solid mate ⁇ al
  • the precoat acts as an
  • the scraper 11 removes a layer of solid material (referred to as
  • the precoat layer becomes
  • FIGURE 2 accomplishes removal of the precoat layer by using an oscillating
  • spray pipe 14 fitted with a spray nozzle 15.
  • the spray nozzle 15 moves between the periphery and center of the disc 2, sprays water on the disc 2, and removes
  • oscillating shower is increased to correspond to the interior region of the disc, then insufficient spray is achieved at the outer region of the disc.
  • the disc filter shown in FIGURES 1 and 2 may also be equipped with an
  • the solid particles must be distributed throughout the liquid. This allows the solid
  • an agitator 24 is placed in the container 5. Air is forced through the agitator 24
  • the liquid in the disc filter is forced towards the discs 2 through pressure in the container 5. As the liquid passes through the disc there is a
  • the disc filter includes oscillating showers
  • Each oscillating shower moves over the surface of the disc at a varying speed so that
  • filter also includes an agitator that forces a portion of the input slurry through a
  • the oscillating shower that oscillates at varying speeds sprays a uniform
  • the eductor agitator receives the input slurry and uses a portion of the
  • the filter capacity is also improved by not introducing air into the slurry.
  • FIGURE 1 is a cross-sectional side view of a conventional disc filter
  • FIGURE 2 is a cross-sectional end view of the conventional disc filter
  • FIGURE 3 is a cross-sectional side view of a conventional disc filter
  • FIGURE 4 is a cross-sectional end view of the disc filter of the present
  • FIGURE 4A is a block diagram of the disc filter control system
  • FIGURE 5 is an enlarged view of the oscillating shower wand
  • FIGURE 6 is a cross-sectional side view of the disc filter of FIGURE 4.
  • FIGURE 7 is an enlarged view of the oscillating shower actuator
  • FIGURES 8A-8C illustrate the path and speed of the oscillating shower
  • FIGURE 9 is an enlarged, exploded view of an eductor agitator.
  • FIGURE 4 is cross-sectional end view of the disc filter of the present
  • the disc filter includes at least one disc 2.
  • the disc 2 is similar to
  • the discs 2 may be a perforated material such as metal and covered with a filter material such as polypropylene.
  • the filter material is referred to
  • Each disc 2 is divided into disc sectors 70 which are used to generally as the filter cloth.
  • Each disc 2 is divided into disc sectors 70 which are used to generally as the filter cloth.
  • the discs 2 are positioned within a container 5
  • the level of the slurry can vary but typically is
  • each sector 70 fully enters the slurry and an amount of solid material is deposited on the surface of
  • each disc sector 70 The solid material is then removed from each sector 70 to
  • An oscillating shower 30 includes an oscillating shower wand 32 having
  • the oscillating shower 30 is used to remove the precoat layer
  • the disc 2 is rotated counter-clockwise (as shown of Fig. 4) at a low speed and the oscillating shower removes the precoat layer formed on the disc 2.
  • a scraper mechanism 40 includes a blade 42 that removes the cake layer
  • a chute shower 44 sprays water into the chute 46 and allows
  • the solid material to slide towards the bottom of the chute 46.
  • the solid material is sluiced down into the lime mud mix tank, using chute sprays and recirculated
  • a wash shower 50 is an optional addition to the disc filter.
  • shower includes a wash pipe 52 and a plurality of wash shower nozzles 54.
  • wash shower nozzles 54 spray water at the solid material formed on the disc
  • Wash shower 50 replaces a portion of the liquid with water thereby preventing the
  • eductor agitator 60 agitates the slurry in the container 5. If the slurry is not
  • the solid material will collect at the bottom of the container 5. This reduces the filter efficiency.
  • the solid material accumulates at the bottom of the
  • the educator agitator 60 receives the input slurry from the disc filter
  • eductor agitator 60 is positioned at each side of each disc. The details of the
  • slurry is fed into the container 5 through an inlet pipe.
  • the container 5 is then
  • wash shower 50 if used, displaces the liquid to
  • the container is
  • the discs 2 are slowly rotated, and the oscillating shower 30 removes the precoat layer. Once the precoat layer is removed, the filtering process is
  • decision to initiate the oscillating shower 30 may be made automatically by control circuitry. When either a high slurry level or a pressure drop is detected by control
  • the oscillating shower is activated.
  • a slurry level sensor 200 positioned within the container 5 detects the level of the slurry.
  • a pressure sensor 210 detects if the pressure in the vacuum system is increasing.
  • control circuitry 220 initiates the precoat removal cycle.
  • FIGURE 5 is an enlarged view of the oscillating shower 30 shown in
  • the oscillating shower wand 32 is made up of an upper section 35
  • the coupler 36 which has threads formed in both ends.
  • the coupler 36 allows the nozzle
  • the nozzles 34 are formed on the nozzle section 33
  • the oscillating shower wand 32 receives water from the high
  • the high pressure pipe 31 is mounted in bearings 39 which are
  • FIGURE 5 shows the oscillating shower wand
  • FIGURE 6 is a side cross-sectional view of the disc filter. As described
  • the oscillating shower wands 32 are coupled to a high pressure pipe 31.
  • the high pressure pipe 31 rotates within bearings 39 (shown in FIGURE 5) which are supported by bearing support brackets 38.
  • Nozzles 34 extend away
  • the oscillating shower wands 32 are driven by a pneumatic actuator 82 which is mounted on an actuator support 80.
  • the pneumatic actuator 82 drives
  • a feed pipe 84 which oscillates the high pressure pipe 31.
  • the feed pipe includes a rotating
  • the bearing/swivel joint 86 is mounted to a
  • the rotating section 89 is connected to the high
  • mounting plate 81 seals the container 5 at the area where the high pressure pipe
  • FIGURE 7 is an enlarged end view of the region including the pneumatic
  • the bearing/swivel joint 86 is not shown in FIGURE 7 for clarity.
  • the pneumatic actuator 82 is mounted to a pivot joint 88 which allows the
  • actuator arm 85 is connected to the rotating section 89 through a connection arm (not shown in the drawings) welded to the rotating section 89 and rotatably
  • FIGURES 8A-8C illustrate the path followed by the oscillating shower
  • FIGURE 8B illustrates a double
  • FIGURE 8C illustrates a triple pass.
  • the path of the oscillating shower nozzles 34 is shown by track 90.
  • the oscillating shower wand 32 travels between
  • the first radial position is at or near the periphery of the
  • the second radial position is near the center of the disc 2.
  • the track 90 is divided into a plurality of track sections 92 that indicate the
  • the track sections 92 near the center of the disc are larger than the track
  • the pneumatic arm 85 is driven faster when the nozzles 34 are near the center of the disc and slower when
  • the nozzles 34 are near the periphery of the disc. There is less surface area near
  • the nozzles 34 slow down in order to achieve
  • FIGURE 8B illustrates the amount of coverage when the oscillating shower makes
  • FIGURE 8C illustrates that the entire
  • FIGURE 9 is an enlarged, exploded view of the eductor agitator 60 shown in FIGURE 4.
  • the eductor agitator 60 includes an eductor inlet pipe 62.
  • eductor inlet pipe 62 is fed from the main inlet pipe that provides the slurry to the
  • the eductor inlet pipe 62 is coupled to an eductor nozzle 64 which
  • the eductor nozzle 64 is mounted on the
  • the eductor inlet pipe 62 has a flange 622 which provides for mounting the inlet pipe 62 and the nozzle 64 to an eductor assembly 66.
  • assembly 66 has a flange 662 which provides an area for mounting the eductor
  • An eductor inlet 664 is a cylindrical opening
  • the feed slurry is fed from the feed pipe into the inlet pipe 62 and through the
  • the nozzle 64 directs the feed through the center of the eductor
  • eductor agitators 60 are placed within the container 5. As shown in FIGURE 6, an
  • eductor agitator 60 is preferably placed at each side of each disc 2. In this way,
  • the eductor agitators 60 may be
  • the oscillating shower uses variable speed to uniformly apply water to the entire surface of the discs in a disc
  • the disc filter In accordance with still another feature of this invention, the disc filter
  • the eductor agitators also prevent the solid material from accumulating at the bottom of the container.

Abstract

An oscillating shower (30) for use with a disc filter. The disc filter includes at least one disc (2) and oscillating showers that periodically remove a precoat layer of solids from the surface of the disc. Each oscillating shower (30) moves over the surface of the disc (2) at a varying speed so that water is uniformly applied to the interior and exterior of the disc. At the interior of the disc, where there is a smaller surface area, the oscillating shower moves faster than at the exterior of the disc where the surface area is greater.

Description

OSCILLATING SHOWER FOR DISC FILTER
Background of the Invention
Field of the Invention
The invention relates generally to an agitator used in a disc filter and in particular to an eductor agitator that is driven by the input slurry.
Prior Art
Disc filters for separating solid particles from liquid are known in the art.
Published International Patent application WO 93/23140 discloses a conventional
rotatable disc filter. As shown in FIGURE 1 , the disc filter includes a plurality of hollow discs 2 having side walls 3 of a filter material. The hollow discs 2 are
coupled to a hollow axle 4 through holes 9. The discs 2 are positioned within a
container 5 which has an inlet 6 (shown in FIGURE 2) for introducing a slurry of
liquid containing solid particles into the container 5. A vacuum pump 7 draws the
liquid through the discs 2. The solid particles accumulate on the surface of the
filter material 3, thereby separating the liquid from the solid particles.
As shown in FIGURE 2, the container 5 is filled approximately half way with the slurry. Sections of the disc 2 rotate counter-clockwise, enter the slurry and
emerge coated with solid material. A scraper 1 is used to remove solid mateπal
formed on the disc 2. It is desirable to leave a certain amount of the solid
material, referred to as the precoat, on the disc 2. The precoat acts as an
additional filter. The scraper 11 removes a layer of solid material (referred to as
the cake layer) formed on top of the precoat layer The cake falls into a chute 12
and is transferred away from the filter using known conveyance mechanisms. After the filter has been running for some time, the precoat layer becomes
less permeable and does not provide adequate filtering. Accordingly, it is
necessary to periodically remove the precoat layer. The disc filter shown in
FIGURE 2 accomplishes removal of the precoat layer by using an oscillating
spray pipe 14 fitted with a spray nozzle 15. The spray nozzle 15 moves between the periphery and center of the disc 2, sprays water on the disc 2, and removes
the precoat layer.
The use of an oscillating shower to remove solid material from a disc filter
is also described in U.S. Patents 3,252,577 and 4,332,680. A problem common to all these devices is that the shower arm moves at a fixed speed. Because there is
much less disc surface area at the interior of the disc, more water than necessary
is applied to the inner portion of the disc which wastes water. If the speed of the
oscillating shower is increased to correspond to the interior region of the disc, then insufficient spray is achieved at the outer region of the disc.
The disc filter shown in FIGURES 1 and 2 may also be equipped with an
agitator as shown in FIGURE 3. In order for the disc filter to operate efficiently,
the solid particles must be distributed throughout the liquid. This allows the solid
particles to contact the entire surface area of the disc 2 and provides for optimal
filtering. In addition, the agitation prevents the solid particles from accumulating
at the bottom of the container 5 and forming a solid mass. As shown in FIGURE
3, an agitator 24 is placed in the container 5. Air is forced through the agitator 24
in order to agitate the slurry. However, using air as the source of the agitation
has drawbacks. The liquid in the disc filter is forced towards the discs 2 through pressure in the container 5. As the liquid passes through the disc there is a
pressure drop. Air bubbles entrained in the liquid will expand at this point and as
a result will partially block the passage of the liquid in the precoat, and thereby
reduce the filter capacity.
Summary of the Invention:
The above-discussed and other drawbacks and deficiencies of the prior art
are overcome or alleviated by the disc filter system of the present invention. In
accordance with the present invention, the disc filter includes oscillating showers
that periodically remove the precoat layer of solids from the filter discs. Each oscillating shower moves over the surface of the disc at a varying speed so that
water is uniformly sprayed on the interior and exterior of the disc. At the interior of
the disc, where there is a smaller surface area, the oscillating shower moves
faster than at the exterior of the disc where the surface area is greater. The disc
filter also includes an agitator that forces a portion of the input slurry through a
nozzle and eductor assembly. The output of the eductor assembly agitates the
slurry in the container and prevents the solid particles from settling in the bottom
of the container.
The oscillating shower that oscillates at varying speeds sprays a uniform
amount of water on the surface of the disc. This reduces the amount of water
used in removing the precoat layer and reduces the number of nozzles. Reducing
the number of nozzles decreases the initial and maintenance costs for the disc
filter. The eductor agitator receives the input slurry and uses a portion of the
slurry inside the filter vessel to agitate the contents of the disc filter. This
eliminates the source of compressed air previously used for agitation and thus
reduces the energy consumption of the disc filter. The filter capacity is also improved by not introducing air into the slurry.
The above-discussed and other features and advantages of the present
invention will be appreciated and understood by those skilled in the art from the following detailed description and drawings.
Brief Description of the Drawings
Referring now to the drawings wherein like elements are numbered alike in
the several FIGURES:
FIGURE 1 is a cross-sectional side view of a conventional disc filter;
FIGURE 2 is a cross-sectional end view of the conventional disc filter;
FIGURE 3 is a cross-sectional side view of a conventional disc filter
including an agitator;
FIGURE 4 is a cross-sectional end view of the disc filter of the present
invention;
FIGURE 4A is a block diagram of the disc filter control system;
FIGURE 5 is an enlarged view of the oscillating shower wand;
FIGURE 6 is a cross-sectional side view of the disc filter of FIGURE 4;
FIGURE 7 is an enlarged view of the oscillating shower actuator;
FIGURES 8A-8C illustrate the path and speed of the oscillating shower
over the filter discs for first and subsequent passes; and FIGURE 9 is an enlarged, exploded view of an eductor agitator.
Detailed Description of the Invention
FIGURE 4 is cross-sectional end view of the disc filter of the present
invention. The disc filter includes at least one disc 2. The disc 2 is similar to
those described in the prior art in that solid material is removed from liquid by forcing the liquid through filtering discs 2. The liquid is forced through the discs 2
by creating a pressure differential between the container or vessel 5 and the
interior of discs 2 (e.g. by pressurizing container 5 or creating a vacuum in the
interior of discs 2). The discs 2 may be a perforated material such as metal and covered with a filter material such as polypropylene. The filter material is referred
to generally as the filter cloth. Each disc 2 is divided into disc sectors 70 which
are covered with the filter cloth. The discs 2 are positioned within a container 5
that holds the solid/liquid slurry. The level of the slurry can vary but typically is
approximately the center of the disc 2. As the discs 2 rotate, each sector 70 fully enters the slurry and an amount of solid material is deposited on the surface of
each disc sector 70. The solid material is then removed from each sector 70 to
separate the solid from the liquid.
An oscillating shower 30 includes an oscillating shower wand 32 having
shower nozzles 34. The oscillating shower 30 is used to remove the precoat layer
of solids formed on the surface of the disc 2. During normal filtering, the
oscillating shower 30 is not used. At the end of a filtering cycle, the precoat layer
has become impervious to effectively filter and must be removed. The container 5
is drained, the disc 2 is rotated counter-clockwise (as shown of Fig. 4) at a low speed and the oscillating shower removes the precoat layer formed on the disc 2.
In accordance with an important feature of the present invention, the oscillating
shower uniformly sprays the surface of the disc 2 at a varying speed and in a
predetermined pattern. The details of the oscillation pattern of the oscillating
shower 30 are described below with reference to FIGURES 8A-8C.
A scraper mechanism 40 includes a blade 42 that removes the cake layer
from the precoat layer. During filtration, the disc 2 rotates counter-clockwise (as shown on Fig. 4). As each disc sector 70 passes through the slurry and emerges
from the slurry, additional solid material is deposited on the surface of the disc sector 70. As the disc sectors 70 pass the scraper blade 42, the cake layer
formed on top of the precoat layer is removed. The removed solid material falls
into the chute 46. A chute shower 44 sprays water into the chute 46 and allows
the solid material to slide towards the bottom of the chute 46. The solid material is sluiced down into the lime mud mix tank, using chute sprays and recirculated
slurry from the mix tank.
A wash shower 50 is an optional addition to the disc filter. The wash
shower includes a wash pipe 52 and a plurality of wash shower nozzles 54. The
wash shower nozzles 54 spray water at the solid material formed on the disc
sectors 70 as each disc sector 70 while it is in the slurry. When each disc sector
70 emerges from the slurry, it contains both the solid and some of the liquid.
Wash shower 50 replaces a portion of the liquid with water thereby preventing the
liquid which contain higher concentration of chemicals from being discarded in
chute 40. This increases the filtering efficiency of the disc filter. In accordance with yet an another important feature of this invention, an
eductor agitator 60 agitates the slurry in the container 5. If the slurry is not
agitated, the solid material will collect at the bottom of the container 5. This reduces the filter efficiency. The solid material accumulates at the bottom of the
container 5 can be extremely difficult to remove and can cause mechanical problems. The educator agitator 60 receives the input slurry from the disc filter
inlet pipe and a portion of the slurry in the vessel and emits a stream of slurry towards the center of the vessel. This sufficiently agitates the slurry to prevent
settling of the solid material but does not require the deleterious use of air which
conventional systems have used as described above. As shown in FIGURE 6, an
eductor agitator 60 is positioned at each side of each disc. The details of the
eductor agitator 60 are described below with reference to FIGURE 9.
The operation of the disc filter will now be summarized. The liquid/solid
slurry is fed into the container 5 through an inlet pipe. The container 5 is then
pressurized and the discs 2 are rotated counter-clockwise (as shown in Fig. 4).
As the disc sectors 70 emerge from the slurry, they are coated with a cake of the
solid material and liquid. The wash shower 50, if used, displaces the liquid to
prevent the liquid from being discarded down chute 40. The cake layer formed on top of the precoat layer is then removed by scraper blade 42. This process
continues for a desired time period until the precoat layer becomes too impervious
and must be removed to sustain filter capacity. At this time, the container is
drained, the discs 2 are slowly rotated, and the oscillating shower 30 removes the precoat layer. Once the precoat layer is removed, the filtering process is
resumed.
Instead of removing the precoat at the end of the filtering cycle, the
decision to initiate the oscillating shower 30 may be made automatically by control circuitry. When either a high slurry level or a pressure drop is detected by control
circuity, the oscillating shower is activated. As shown in FIGURE 4A, a slurry level sensor 200 positioned within the container 5 detects the level of the slurry.
A pressure sensor 210 detects if the pressure in the vacuum system is increasing.
Both these conditions indicate that flow through the filter discs 2 is impeded and
that the filter sectors 70 need cleaning. Upon detection of one or both of these conditions, the control circuitry 220 initiates the precoat removal cycle.
FIGURE 5 is an enlarged view of the oscillating shower 30 shown in
FIGURE 4. The oscillating shower wand 32 is made up of an upper section 35
and a nozzle section 33. These two sections of pipe are joined through coupler
36 which has threads formed in both ends. The coupler 36 allows the nozzle
section 33 to be removed from the upper section 35 for replacement and/or
maintenance of nozzles 34. The nozzles 34 are formed on the nozzle section 33
and direct water away from the nozzle section 33 towards the surface of the discs
2. Gussets 37 are formed on the upper section 35 to strengthen the oscillating
shower wand 32. The oscillating shower wand 32 receives water from the high
pressure pipe 31. The high pressure pipe 31 is mounted in bearings 39 which are
supported by bearing brackets 38. FIGURE 5 shows the oscillating shower wand
32 in three positions. FIGURE 6 is a side cross-sectional view of the disc filter. As described
above, the oscillating shower wands 32 are coupled to a high pressure pipe 31.
The high pressure pipe 31 rotates within bearings 39 (shown in FIGURE 5) which are supported by bearing support brackets 38. The oscillating shower wands 32
are positioned adjacent to each surface of the discs 2. Nozzles 34 extend away
from the oscillating shower wand 32 and direct a spray of water at the surface of
the discs 2. The precoat layer removed by nozzles 34 falls into chutes 40 as
previously described.
The oscillating shower wands 32 are driven by a pneumatic actuator 82 which is mounted on an actuator support 80. The pneumatic actuator 82 drives
an actuator arm 85 which oscillates the high pressure pipe 31. A feed pipe 84
provides water to the high pressure pipe 31. The feed pipe includes a rotating
section 89 which is coupled to the high pressure pipe 31. A bearing/swivel joint
86 couples the rotating section 89 to the feed pipe 84 and allows water to pass
from the feed pipe 84 to the rotating section 89 and allows the rotating section 89
to rotate relative to the feed pipe 84. The bearing/swivel joint 86 is mounted to a
support bearing bracket 87. The rotating section 89 is connected to the high
pressure pipe 31 through a split seal 83 and a seal mounting plate 81. The seal
mounting plate 81 seals the container 5 at the area where the high pressure pipe
31 extends through the container wall. As the actuator arm 85 is driven up and
down, the feed pipe 84 remains stationary while the rotating section 89 and the
high pressure pipe 31 are rotated. FIGURE 7 is an enlarged end view of the region including the pneumatic
actuator 82. The bearing/swivel joint 86 is not shown in FIGURE 7 for clarity.
The pneumatic actuator 82 is mounted to a pivot joint 88 which allows the
pneumatic actuator to move away from the rotating section 89 as needed. The
actuator arm 85 is connected to the rotating section 89 through a connection arm (not shown in the drawings) welded to the rotating section 89 and rotatably
coupled to the actuator arm 85. As previously described, as the actuator arm 85
moves up and down, the rotating section 89 rotates and causes the high pressure
pipe 31 to rotate in an oscillatory manner. The rotation of the high pressure pipe 31 oscillates the oscillating shower wands 32 over the surfaces of discs 2.
FIGURES 8A-8C illustrate the path followed by the oscillating shower
nozzles 34 over the surface of a disc 2 (shown in FIGURE 4). FIGURE 8A
illustrates a single pass by the oscillating shower, FIGURE 8B illustrates a double
pass and FIGURE 8C illustrates a triple pass. The path of the oscillating shower nozzles 34 is shown by track 90. The oscillating shower wand 32 travels between
a first radial position and a second radial position on the surface of the disc 2. As
shown in FIGURE 8A, the first radial position is at or near the periphery of the
disc 2. The second radial position is near the center of the disc 2.
The track 90 is divided into a plurality of track sections 92 that indicate the
distance that the shower nozzles 34 travel per unit time. As shown in FIGURE
8A, the track sections 92 near the center of the disc are larger than the track
sections 92 at the periphery of the disc. The shower nozzles 34 move faster near
the center of the disc than at the periphery of the disc. The pneumatic arm 85 is driven faster when the nozzles 34 are near the center of the disc and slower when
the nozzles 34 are near the periphery of the disc. There is less surface area near
the center of the disc 2 and thus, the nozzles 34 moves faster near the center of
the disc and still effectively spray the disc surface. As the surface area increases
away from the center of the disc, the nozzles 34 slow down in order to achieve
uniform coverage of the disc surface. The speed of the oscillating shower wand 32 is dependent upon the radial position of the oscillating shower wand 32. FIGURE 8B illustrates the amount of coverage when the oscillating shower makes
two passes over the surface of the disc. FIGURE 8C illustrates that the entire
disc surface is covered when the oscillating shower makes three passes over the
surface of the disc.
The variance in the speed of the shower nozzles provides several
advantages. Less nozzles are needed to effectively cover the surface of the disc
as compared to stationary showers. This reduces the costs of manufacturing and
maintaining nozzles. In addition, less water is used by the varying speed
oscillating shower than conventional fixed speed showers. Further, it provides a
more thorough job cleaning the surface, without leaving uncleaned areas.
FIGURE 9 is an enlarged, exploded view of the eductor agitator 60 shown in FIGURE 4. The eductor agitator 60 includes an eductor inlet pipe 62. The
eductor inlet pipe 62 is fed from the main inlet pipe that provides the slurry to the
container 5. This eliminates the source of compressed air used in the prior art
systems and reduces energy consumption. The eductor inlet pipe 62 is coupled to an eductor nozzle 64 which
increases the speed of the slurry. The eductor nozzle 64 is mounted on the
eductor inlet pipe 62. The inlet pipe has a flange 622 which provides for mounting the inlet pipe 62 and the nozzle 64 to an eductor assembly 66. The eductor
assembly 66 has a flange 662 which provides an area for mounting the eductor
assembly 66 to the container wall. An eductor inlet 664 is a cylindrical opening
having an inner diameter slightly larger than the outer diameter of the nozzle 64.
The feed slurry is fed from the feed pipe into the inlet pipe 62 and through the
nozzle 64. The nozzle 64 directs the feed through the center of the eductor
assembly 66. This creates a low pressure zone in the eductor assembly which
draws additional slurry already in the container through the eductor assembly 66.
Hence, the flow out of the eductor assembly 66 is increased multiple times in
relation to the feed slurry flow emitted from the eductor nozzle 64. A plurality of
eductor agitators 60 are placed within the container 5. As shown in FIGURE 6, an
eductor agitator 60 is preferably placed at each side of each disc 2. In this way,
the slurry near each disc 2 surface is agitated. The eductor agitators 60 may be
fed individually or from a common header pipe 668.
In accordance with the present invention, the oscillating shower uses variable speed to uniformly apply water to the entire surface of the discs in a disc
filter. Near the periphery of the disc, the oscillating shower wand moves slower
than near the center of the disc due to the larger amount of surface area per
degree at the periphery of the circular disc. This variation in speed reduces the
amount of water used and reduces the number of nozzles necessary to distribute the water. In accordance with still another feature of this invention, the disc filter
includes eductor agitators that maintain the solid material in suspension so that
filtering efficiency is increased. The eductor agitators also prevent the solid material from accumulating at the bottom of the container.
While preferred embodiments have been shown and described, various
modifications and substitutions may be made thereto without departing from the
spirit and scope of the invention. Accordingly, it is to be understood that the
present invention has been described by way of illustration and not limitation.

Claims

What is claimed is
CLAIM 1 An oscillating shower for use with a disc filter including at least one disc, the improvement comprising said oscillating shower oscillating over a surface of the disc at a varying speed
CLAIM 2 The oscillating shower of claim 1 wherein the oscillating shower travels radially over the surface of the disc
CLAIM 3 The oscillating shower of claim 2 wherein the speed of oscillating shower is dependent on the radial position of the oscillating shower
CLAIM 4 The oscillating shower of claim 3 wherein the speed of the oscillating shower is greater at a second radial location than at a first radial location
CLAIM 5 The oscillating shower of claim 4 wherein the first radial position is near the periphery of the disc and the second radial position is near the center of the
CLAIM 6 The oscillating shower of claim 1 wherein said oscillating shower comprises an oscillating shower wand and at least one nozzle for directing liquid at the surface of the disc
CLAIM 7 The oscillating shower of claim 6 wherein said oscillating shower wand is connected to a high pressure pipe, said high pressure pipe providing said liquid to said oscillating shower wand CLAIM 8 A filter having a filter medium and an oscillating shower for cleaning the filter medium, the disc filter comprising at least one sensor for detecting a predetermined condition, and control circuitry responsive to said at least one sensor for initiating the oscillating shower
CLAIM 9 The filter of claim 7 wherein said filter contains a slurry and said sensor comprises a slurry level detector for detecting the level of the slurry
CLAIM 10 The filter of claim 7 wherein said filter is a pressure filter and said sensor comprises a pressure sensor for detecting the pressure in the filter
CLAIM 11 The filter of claim 7 wherein said filter is a pressure filter containing a slurry and said at least one sensor comprises a slurry level detector for detecting the level of the slurry and a pressure sensor for detecting the pressure in the filter
PCT/US1997/018751 1996-10-15 1997-10-14 Oscillating shower for disc filter WO1998016293A1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
CA002268781A CA2268781A1 (en) 1996-10-15 1997-10-14 Oscillating shower for disc filter
AU51466/98A AU5146698A (en) 1996-10-15 1997-10-14 Oscillating shower for disc filter
SE9901346A SE518835C2 (en) 1996-10-15 1999-04-15 Disk filter oscillating shower
FI990840A FI990840A (en) 1996-10-15 1999-04-15 Distinctive shower for a disc filter

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US72992296A 1996-10-15 1996-10-15
US08/729,922 1996-10-15

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WO1998016293A1 WO1998016293A1 (en) 1998-04-23
WO1998016293A9 true WO1998016293A9 (en) 1998-07-09

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AU (1) AU5146698A (en)
CA (1) CA2268781A1 (en)
FI (1) FI990840A (en)
ID (1) ID27674A (en)
SE (1) SE518835C2 (en)
WO (1) WO1998016293A1 (en)

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Publication number Priority date Publication date Assignee Title
US11291935B2 (en) * 2018-04-13 2022-04-05 Veolia Water Solutions & Technologies Support Rotary disc filter having a backwash system that includes a compact nozzle support structure
CA3132555A1 (en) * 2019-03-08 2020-09-17 Steve C. Benesi Filter apparatus, filter disc sectors, filter elements and uses
WO2024079561A1 (en) * 2022-10-11 2024-04-18 Veolia Water Solutions & Technologies Support Rotary disc filter having a high pressure media cleaning system

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US4975189A (en) * 1988-12-09 1990-12-04 Liszka John A Cleaning sprays for disc filters
SE470227C (en) * 1992-05-15 2001-10-08 Caustec Ab Apparatus for separating solid particles from a liquid mixture
AT398706B (en) * 1992-11-06 1995-01-25 Andritz Patentverwaltung METHOD AND DEVICE FOR FILTRATION
FI96281B (en) * 1993-07-15 1996-02-29 Ahlstroem Oy Method and apparatus for precipitating sludge slurry with a disc filter
US5362401A (en) * 1993-12-14 1994-11-08 Aqua-Aerobic Systems, Inc. Method and apparatus for cleaning a filter apparatus

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