Note: Descriptions are shown in the official language in which they were submitted.
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SELF-CLEANING WATER FILTER
SPECIFICATION
BACKGROUND OF THE INVENTION
This invention relates generally to filter devices and, more particularly, to
water system filters for small particulate contaminants.
It is well-known that the mechanical cleaning of a filter surface can be
accomplished by having a brush or scraper drag along the filter surface where
deposits
have accumulated. In certain configurations, the brush or scraper is mounted
at one
end between two walls but with a significant portion of the brush or scraper
projecting
beyond the walls. Such configurations are shown in U.S. Patent Nos. 148,557
(Gillespie et al.); 556,725 (Farwell); 740,574 (Kohlmeyer) and 793,720
(Godbe). In
conventional filter systems, the particulate contaminants are driven off the
filter surface
and are deposited in a hopper or tank along with the fluid being filtered,
thus discarding
large amounts of the fluid being filtered.
The use of a brush, or high speed cleaning spray, disposed between a
pair of walls for cleaning a cylindrical filter is known in the art, as is
disclosed in U.S.
Patent Nos. 5,423,977 (Aoki et al.) and 5,595,655 (Steiner et al.) and Swiss
Patent No.
22,863 (Zingg). Another variation employs a backwash that drives the
particulate
contaminants off of the cylindrical filter, as is disclosed in U.S. Patent No.
3,338,416
(Barry).
An exemplary use of such filters is in a water desalination system that is
available on ships. Shipboard water/salt water straining is a specialized
straining
process. In particular, the water/salt water flow is initially pre-strained
for gross
particulate contaminants, such that any particulate contaminants remaining in
the
water/salt water flow are extremely small (e.g., < 100 microns, with a large
percentage
being less than 25 microns). As a result, where these small particulate
contaminants
are captured by a downstream strainer (e.g., a wedge wire screen strainer),
both on
and within the strainer surface, and then later dislodged during the strainer
cleaning
process, these extremely small particulate contaminants do not fall by gravity
toward
a drain but remain suspended in the water/salt water and will re-attach to the
strainer
surface. Therefore, there remains a need for a cleaning device that can
dislodge such
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extremely small particulate contaminants off of the downstream strainer
surface, as
well as from within the strainer surface, and then ensure that these
particulate
contaminants flow out through the drain rather than re-attaching to the
strainer surface.
Thus, there is a need for an improved system for removing undesired
particulate contaminants from a water/salt water flow and without interrupting
that
water/salt water flow to the engines, while minimizing the amount of fluid
removed
therewith. It is to just such a system that the present invention is directed.
SUMMARY OF THE INVENTION
A water cleaning system is disposed within a water flow having
particulate contaminants therein. As mentioned earlier, the particulate
contaminants
that need to be removed from the water flow are extremely small, less than 100
microns, and a large percentage of these less than 25 microns, therefore do
not settle
out by gravity. The invention of the present application is well-suited to
removing these
small particulate contaminants from the water flow and into a drain.
In particular, a water filter is disposed within a water flow having
particulate contaminants therein. The water filter comprises: a porous member
in fluid
communication with the water flow such that the water flow enters the porous
member
through a first porous member surface and exits through a second porous member
surface and wherein the water flow deposits the particulate contaminants on
the first
porous member surface; particulate-removing means disposed to be in close
proximity
with the porous member for removing particulate contaminants from the first
porous
member surface along substantially the entirety of the length of the first
porous
member surface; a pair of flow confining walls are disposed to be in close
proximity
with the first porous member surface along substantially the entirety of the
length of the
first porous member surface for defining a chamber; a partition divides the
chamber
into a first subchamber and a second subchamber along the length of the
chamber; a
drive mechanism is provided for displacing the porous member for continuously
directing particulate contaminants deposited on the first porous surface past
the
particulate removing means for continuously dislodging the particulate
contaminants
from the first porous member surface into the first subchamber; the partition
includes
first and second portions on opposite sides of the particulate removing means
and
each portion has a plurality of apertures for passing the dislodged
particulate
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contaminants from the first subchamber into the second subchamber; anda drain
is in
communication with the second subchamber and through which the dislodged
particulate contaminants are removed when the drain is opened.
A method is provided for cleaning a water flow having particulate
contaminants therein. The method comprises the steps of: disposing a porous
member
in fluid communication with the water flow such that the water flow enters the
porous
member through a first porous member surface and exits through a second porous
member surface so that the water flow deposits the particulate contaminants on
the
first porous member surface; positioning a pair of flow confining walls
adjacent the first
porous member surface to define a chamber and positioning a respective
flexible
member between a respective flow confining wall and the first porous surface
member,
and wherein the respective flexible members are in contact with the first
porous
surface; positioning a particulate-removing means closely-adjacent the porous
member; dividing the chamber into first and second subchambers with a
partition
having first and second portions on opposite sides of the particulate removing
means
and each portion having a plurality of apertures to provide fluid
communication
between the first and second subchambers and wherein the second subchamber is
in
fluid communication with a drain when the drain is opened; displacing the
porous
member to permit the particulate-removing means to dislodge particuiate
contaminants
trapped on the first porous member surface into the first subchamber; and
opening the drain to cause the dislodged particulate contaminants to pass
through the
plurality of apertures into the second subchamber and out into the drain.
A water cleaning system is provided for use with a water flow having
particulate contaminants therein. The cleaning system comprises: an inlet
valve for
controlling the water flow having particulate contaminants therein forming a
contaminated water flow and wherein the contaminated water flow flows through
a first
output port of the inlet valve; a stationary porous member positioned in the
contaminated water flow that passes through the first output port and wherein
the
contaminated water flow enters the stationary porous member through a first
porous
member surface and exits through a second porous member surface towards a
second
output port, and wherein the contaminated water flow deposits the particulate
contaminants on the first porous member surface to form a clean water flow
that flows
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toward the second output port; an outlet valve coupled to the second output
port for
controlling the clean water flow; a flow control means, operated during a
porous
member cleaning process, having a flow control means input coupled to a source
of
water and a flow control means output coupled to the second output port and
wherein
the flow control means controls a reverse flow of the clean water that flows
from the
second porous member surface through the first porous member surface for
dislodging
the particulate contaminants from the first porous member surface to form a
contaminated reverse flow of water; a drain valve coupled to the first output
port for
directing the contaminated reverse flow of water towards a drain during the
cleaning
process; and the inlet valve and outlet valve are closed during the cleaning
process.
A method is provided for cleaning a contaminated water flow having
particuiate contaminants therein. The method comprises the steps of:
positioning a
stationary porous member in the contaminated water flow such that the
contaminated
water flow enters the stationary porous member through a first porous member
surface
and exits through a second porous member surface toward an output port, and
wherein
the contaminated water flow deposits the particulate contaminants on the first
porous
member surface; isolating the stationary porous member from the contaminated
water
flow during a cleaning process; passing a reverse flow of clean water from the
output
port and through the stationary porous member from the second porous surface
member surface to the first porous member surface for dislodging the
particulate
contaminants from the first porous member surface to form a contaminated
reverse
flow of water; opening a drain to receive the contaminated reverse flow of
water;
discontinuing the reverse flow of clean water while closing the drain to
complete the
cleaning process; and recoupling the stationary porous member to the
contaminated
water flow.
A water filter system for use with a water flow having particulate
contaminants therein. The water filter system comprises: an inlet valve for
controlling
the water flow having particulate contaminants therein forming a contaminated
water
flow and wherein the contaminated water flows through a first output port of
the inlet
valve; a stationary porous member positioned in the contaminated water flow
that
passes through the first output port, and wherein the contaminated water flow
enters
the stationary porous member through a first porous member surface and exiting
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through a second porous member surface towards a second output port, and
wherein
the water flow deposits the particulate contaminants on the first porous
member
surface to form a clean water flow that flows towards the second output port;
a third
output port coupled to a drain through a drain valve; the iet valve being
closed while
the drain valve is opened during a cleaning process for generating a reverse
flow of the
water that flows from the second output port towards the third output port,
wherein the
reverse flow of the clean water flows through the stationary porous member
from the
second porous member surface through the first porous member surface for
dislodging
the particulate contaminants from the first porous member surface to form a
contaminated reverse flow of water that flows into the drain; and the drain
valve being
closed and the inlet valve being opened after the cleaning process is
completed.
DESCRIPTION OF THE DRAWINGS
Many of the intended advantages of this invention will be readily
appreciated when the same becomes better understood by reference to the
following
detailed description when considered in connection with the accompanying
drawings
wherein:
Fig. 1 is a block diagram of the water-desalination system in which the
present invention is located;
Fig. 2 is a top view of the present invention;
Fig. 3 is a partial side view of the present invention;
Fig. 4 is a bottom view of the present invention;
Fig. 5 is a cross-sectional view of the present invention taken along line
5-5 of Fig. 2;
Fig. 6 is partial sectional view taken along line 6-6 of Fig. 5;
Fig. 7 is a partial sectional view taken along line 7-7 of Fig. 5;
Fig. 8 is a cross-sectional view of the present invention using a reverse
flow of clean water/salt water as part of the particulate-removing means;
Fig. 9 is a partial sectional view taken along line 9-9 of Fig. 8;
Fig. 10 is similar to Fig. 9 except that a different reverse flow direction is
depicted;
Fig. 11 is an enlarged, cross-sectional view of a portion of Fig. 5,
depicting different portions of the partition and one of the associated
wipers;
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Fig. 12 is an enlarged, cross-sectional view of a portion of Fig. 5,
depicting the passageways in the particulate-removing means support for use
with the
alternative drain configuration;
Fig. 13 is a partial isometric view of the internal particulate chamber
depicting the partition and one of the wipers comprising the shoes;
Fig. 14 is a schematic of a water/salt water cleaning system using a
stationary water/salt water strainer;
Fig. 15 is a variation of the water/salt water cleaning system of Fig. 14
wherein the downline water/salt water flow is used as the source of the
reverse clean
water/salt water flow;
Fig. 16 is another variation of the invention of Fig. 15;
Fig. 17 is a cross-sectional view of a stationary filter, that can be used in
the systems shown in Figs. 14-16, and having an ultrasonic generator disposed
therein;
Fig. 18 is an enlarged view of the circled portion shown in Fig. 17; and
Fig. 19 is a sectional view of the stationary filter taken along line 19-19
of Fig. 17.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following is a detailed description of the present invention. The
present invention has wide application where straining very small particulate
contaminants, less than 100 microns and large percentage of these are less
than 25
microns, from a water/salt water flow is required, and is not limited to the
environment
shown in Fig. 1, as will be discussed in detail below. The present invention
is
characterized as a non-disposable cleaning device, i.e., having a porous
member that
can be cleaned rather than being thrown away. The term non-disposable is
defined
as an item that does not require periodic replacement, e.g., once a day, week
or
month. Thus, such a non-disposable item has obvious advantages in environments
where storage is limited and cleaning device replenishment facilities are
unavailable,
e.g., ocean-going vessels. Other example systems include power plants,
cogeneration
facilities, etc.
As an exemplary environment, Applicants have depicted a water
desalination system 1 for disclosing the preferred embodiment; such a water
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desalination system 1 may be used on watercraft, e.g., ships and boats.
However, it
should be understood that it is within the broadest scope of the present
invention that
it can be used in any water cleaning system and it is not limited to a water
desalination
system.
Referring now in greater detail to the various figures of the drawing,
wherein like reference characters refer to like parts, there is shown in Fig.
1 at 520 a
self-cleaning water filter of the present invention which forms a part of the
system
1.The water filter system 1 comprises five stages of straining/filtration
followed by a
reverse osmosis stage 6. A pump 2 pumps sea water into a 1/8" perforation self
cleaning strainer 3 which discharges to a cyclone separator 4 (also referred
to in the
art as a "centrifugal separator"), which discharges to a 50 micron self
cleaning wedge
wire filter 5. The wedge wire filter 5 discharges to the self-cleaning wire
cloth (e.g., 10-
20 micron) water filter 520 which, in turn, discharges to a 3 micron cartridge
filter 6 and
finally through the reverse osmosis membrane 7 to a fresh water user/storage
stage
8.
As shown more clearly in Fig. 2, the water filter 520 comprises two
canisters 26 and 28 that are fed the main water flow with particulates, e.g.,
the sea
water, from the wedge wire filter 5 via a common input manifold 30 (e.g., 2'/2
inch class
150 ANSI flanged input) at the top portion of the filter 520. Each canister 26
and 28
has two inputs from the common manifold 30, as indicated by inputs 32A and 32B
for
canister 26 and by inputs 34A and 34B for canister 28. Each canister 26 and 28
comprises a cylindrical-shaped porous member 36 and 38, respectively, through
which
the sea water flows, as will be discussed in detail later. The porous members
36 and
38 comprise a screen selected from the group consisting of wedge wire, wire
cloth and
perforated metal. In the preferred embodiment, the porous members 36 and 38
comprise wedge wire screens, such as those manufactured by Leem Filtration
Products, Inc. of Mahwah, New Jersey. It is also within the broadest scope of
the
present invention that the porous members 36 and 38 may comprise wire cloth or
perforated metal, as opposed to wedge wire screens. One of the main features
of the
water filter 520 is its ability to filter out fine particulate matter, e.g.,
particulates less
than 100 microns, where a large percentage of these are less than 25 microns.
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Drive mechanisms 40 and 42 (Fig. 3) are provided to rotate the
respective porous members 36 and 38 during the cleaning process about their
respective center axes, only one (44) of which is clearly shown in Fig. 5.
Otherwise,
during normal operation, the porous members 36 and 38 remain stationary.
As can be seen in Fig. 2, sea water enters each canister through its
respective inputs and then flows around the periphery of each porous member 36
and
38; in particular, sea water flow from inputs 32A and 32B are shown by arrows
46A and
46B, respectively, and sea water flow from inputs 34A and 34B are shown by
arrows
48A and 48B, respectively. The inputs 32A and 32B are located on both sides of
an
internal particulate chamber 50 (Fig. 7, which comprises two dislodge
subchambers
50A/50B and a drain subchamber 50C, all of which are discussed later) in
canister 26;
similarly, although not shown, the inputs 34A and 34B in canister 28 are also
located
on both sides of a internal particulate chamber, also comprising two dislodge
subchambers and a drain subchamber. Thus, water/salt water input flow moves
away
from the chamber 50 and around the periphery of the porous members 36 and 38
and
then through them, as is discussed next.
Sea water flow through the porous member is more easily depicted in Fig.
5, which is a cross-sectional view of the canister 26, although it should be
understood
that the following discussion is applicable to the other canister 28. The main
sea water
flow is through the porous member 36, from an outside surface 37 to an inside
surface
39, as indicated by the arrows 52, and down through the hollow interior 41 of
the
porous member 36. As the sea water then flows through the porous member 36,
particulate contaminants are then trapped against the outer surface 37 of the
porous
member 36. The filtered sea water exits into a main output 54 of the canister,
as
shown by the arrow 56. Fig. 4 is a bottom view of both canisters 26 and 28 and
it
shows the main output 54 of canister 26 and a main output 58 of canister 28
feeding
into a common output manifold 60. Thus, sea water flow through the filter 520
is
basically continuous.
When cleaning of the porous member 36 and 38 is required, as indicated
by pressure drop across the filter 520 (as measured by a pressure transducer,
not
shown), the drive mechanisms 40 and 42 are activated to rotate the respective
porous
members. In addition, solenoid valves 72 and 74 (Fig. 3) are activated to open
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respective drains (only one 76 of which is shown in Fig. 5), located directly
below the
drain subchamber 50C, for diverting the particulate debris and a limited
amount sea
water down through a respective drain, rather than through the main outlets 54
and 58.
Furthermore, it is within the broadest scope of this invention to include
other
alternative locations for the drain, e.g., along the chamber, rather than
under it, as will
be discussed in detail later. Opening of the drain 76 (or the alternative
drain) is kept to
a minimum to discard as little sea water as possible while flushing the
particulate
contaminants from the chamber. Thus, for example, the drain 76 can be open all
or
any part of the time that the porous members 36 and 38 are rotating.
Cleaning of the porous members 36 and 38 is accomplished by the
particulate-removing means, only one of which is shown most clearly in Figs.
5, 7, 8
and 9; as such, the following discussion applies to the particulate-removal
means in the
canister 28 also. In the preferred embodiment, the particulate-removing means
comprises an elongated wire brush 62 that spans the length of the porous
member 36.
The brush fibers are in contact with the outside surface 37 of the porous
screen 36 and
thus bear on the outside surface 37 of the porous member 36 along its entire
length.
The brush 62 forms the separation between the two dislodge subchambers 50A and
50B, while the majority of a brush support 63 is disposed inside the drain
subchamber
50C, as shown in Fig. 7.
As mentioned previously, the chamber 50 comprises the two dislodge
subchambers 50A/50B and a drain subchamber 50C. The chamber 50 comprises a
pair of confining walls 64A and 64B, also running the length of the porous
member 36,
that enclose the brush 62/brush support 63. The purpose of these walls 64A and
64B
is to contain the dislodged particulate debris within the chamber 50 so that
substantially
only sea water within this chamber 50 will be discharged through the drain 76
(or
alternative drain 300, to be discussed later) during cleaning. A partition
200, also
running the length of the porous member 36, forms the separation between the
two
dislodge subchambers 50A/50B and the drain subchamber 50C. The partition 200
itself comprises a pair of outer flanges 202A/202B, a base wall 204 and
sidewalls
206A/206B. The base wall 204 is secured between a particulate-removing means
(e.g., brush 62 or scraper) head 61 and the particulate-removing means support
63.
At the bend between the sidewalls 206A/206B and the outer fianges 202A/202B,
the
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partition 200 comprises a plurality of apertures 212 (Figs. 7, 9, 11 and 12)
that permit
the passage of dislodged particulate contaminants from the two dislodge
subchambers
50A/50B to the drain subchamber 50C. Because of the size of the apertures 212
(e.g.,
0.094" diameter), once any particulate contaminants from the two dislodge
subchambers 50A/50B make their way through the partition 200, there is very
little
chance that such particulate contaminants can find their way back through the
apertures 212 and ultimately return to the outer surface 37.
A drain passageway 75, through a strainer support housing 77, is also
shown in Figs. 5. Figs. 7 and 9 also show the passageway 75 in phantom.
At the extreme ends of the confining walls 64A and 64B, respective
wipers 65A and 65B are secured to the outside surfaces of the walls 64A and
64B,
respectively, and which also run the length of the porous member 36. The
wipers 65A
and 65B (e.g., 316 stainless steel, half-hard) are coupled to the ends of the
walls 64A
and 64B using fasteners 78 and plates 79. As can be seen most clearly in Fig.
13,
wiper 65A comprises a plurality of spaced-apart shoes or runners 67 that are
in contact
with the outer surface 37 of the porous member 36. These shoes 67 (e.g.,
0.010" -
0.015" thickness and 1/4" wide and which may be spot-welded to the wiper 65A)
serve
to maintain the wiper 65A a sufficient distance away from the outer surface 37
such
that during cleaning, while the porous member 36 is rotating (direction of
rotation is
shown by the arrow 161 in Fig. 7), the particulate contaminants adhering to
the outer
surface 37 pass beneath the wiper 65A between the shoes and then are driven
off of
the outer surface 37 by the particulate-removing means 62 and into the
dislodge
subchamber 50A. The drain subchamber 50C is in direct fluid communication with
the
drain 76 (or alternative drain 300). When the drain 76 (or alternative drain
300) is
open, any particulate contaminants suspended in the dislodge subchamber 50A
are
pulled toward the apertures 212 in the partition 200 and pass through them and
out to
the drain 76 (or 300).
Any remaining particulate contaminants which cannot be mechanically
driven off of the surface 37 by the brush 62, e.g., particulate contaminants
lodged in
between the outer surface 37 and the inside surface 39 of the porous member 36
(e.g.,
lodged in the wedge wire cells of a porous member 36 comprising wedge wire),
are
subjected to a reverse pressure and are driven out of the surface 37 into the
second
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dislodge subchamber 50B. In particular, unlike the first dislodge subchamber
50A
which is not totally closed off since the wiper 65A stands off from the
outside surface
37 of the porous member 36, the second dislodge subchamber 50B forms a
completely-closed off chamber because the wiper 65B does not include shoes
and,
therefore, is in contact with the outer surface 37 along its entire length.
Thus, the
second dislodge subchamber 50B is subjected completely to the influence of the
pressure differential created between the inside surface 39 of the porous
member 36
and the opened drain pressure which is present in the drain subchamber 50C,
via the
apertures 212. When the drain 76 (or 300) is open, these particulate
contaminants,
lodged in between the outer surface 37 and the inside surface 39 of the porous
member 36, are driven out of that region by the reverse pressure differential
and then
are suspended in the second dislodge subchamber 50B; this pressure
differential also
pulls these particulate contaminants toward the apertures 212 in the partition
200 and
into the drain subchamber 50C for passage through the drain 76 (or 300).
As pointed out earlier, the particulate contaminants are of an extremely
small size, less than 100 microns, and a large percentage of these are less
than 25
microns; as a result, these particulate contaminants do not settle out by
gravity into the
drain but rather, due to their small size, remain suspended in the sea water.
The
invention of the present application is well suited to overcome this problem
as
described below.
It should be understood that the apertures 212 provide for fluid
communication between the first dislodge subchamber 50A and the drain
subchamber
50C and for fluid communication between the second dislodge subchamber 50B and
the drain subchamber 50C. However, because the apertures 212 are small, they
maintain a high velocity of particulate contaminants from both the first and
second
dislodge subchambers 50A and 50B into the drain subchamber 50C under the
influence of the reverse pressure differential. Such a high velocity cannot be
sustained
by replacing the apertures 212 with a slot. Furthermore, replacing the
apertures 212
with a slot would defeat the purpose of maintaining the transferred
particulate
contaminants (i.e., particulate contaminants that have passed from the
dislodge
subchambers 50A/50B) in the drain chamber 50B since the particulate
contaminants
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would not be precluded from making their way back to the outer surface 37 of
the
porous member 36.
In particular, the advantage of using the plurality of apertures, as opposed
to a slot of the type shown in U.S. Patent No. 5,595,655 (Steiner et al.), is
that the
plurality of apertures provides for a rapid flow velocity as opposed to a low
flow velocity
for the slot. For example, if there are 21 apertures that form one set of
apertures in the
partition 200, each having a diameter of approximately 0.094", then the total
area is
approximately
Tr (0.094"/2)2 x 21= 0.1457 in 2. If, on the other hand, a slot having a width
of 0.094"
and a length of 12.594" (i.e., the length from the top of the uppermost
aperture in the
partition 200 to the bottom-most aperture in the partition 200; this is a
reasonable
assumption since the Steiner et al. patent states that the slot is
substantially equal to
the scraper length-Steiner et al. patent, col. 1, lines 61-62) is used, the
area is 1.184
in2. Thus, using a plurality of apertures presents only 1/8 the area of the
slot. As a
result, for a given flow rate (gallons/minute), the slot may provide flow
velocity of 1
ft/sec whereas the apertured partition generates a flow velocity of 8 ft/sec.
The higher
velocity significantly reduces the chance that a particulate will migrate
backwards
through the plurality of apertures and re-attach to the porous surface 36.
It is also within the broadest scope of the present invention to include an
alternative drain 300 configuration as shown most clearly in Figs. 5, 8 and
12. To that
end, a drain 300 is depicted along side the drain subchamber 50C rather than
disposed
underneath the subchamber 50C, as discussed previously. The drain 300
comprises
drain passageways 302, 304 and 306 that form a portion of the particulate-
removing
means support 63. The passageways 302-306 are coupled at one end to a common
manifold 308 through which the dislodged particulate contaminants are disposed
of.
As shown in Fig. 12, the other end of each passageway 302-306 comprises a
respective cross hole 310, 312, and 314 disposed in the drain subchamber 50B.
Thus,
when a drain solenoid valve 316 (Fig. 5) is activated as discussed previously,
particulate matter that has been dislodged from the outer surface 37 of the
porous
members 36/38 into the two dislodge subchambers 50A/50B, passes through the
apertures 212 in the partition 200 into the drain chamber 50B. From there, the
dislodged particulate contaminants are driven into the cross holes 310-314,
through the
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passageways 302-306 and then into the common manifold 308. Thus, particulate
contaminants dislodged from the outer surface 37 of the porous members 36/38
would
be driven into the alternative drain 300.
Alternatively, instead of using a single solenoid valve 316, it is within the
broadest scope of this invention to include dedicated solenoid valves 318, 320
and 322
(Fig. 5) that individually couple respective passageways 302-306 to the common
manifold 308.
It is also within the broadest scope of the present invention that the term
particulate-removing means include a brush, a scraper, or any equivalent
device that
is used to dislodge particulate contaminants from the outside surface 37 of
the porous
members 36 and 38. For example, where larger particulate contaminants are to
be
filtered from the water flow, a scraper (not shown) can be used in place of
the brush
62.
It is also within the broadest scope of the present invention that the
particulate-removing means also encompasses a reverse flow of clean water for
dislodging the particulate contaminants from the water filter 520; or a
reverse flow of
clean water in combination with the particulate-removing member (e.g., brush
or
scraper), discussed previously.
In particular, as shown in Figs. 8-10, a second embodiment of the present
invention comprises a particulate-removing means that includes an elongated
spraying
element 151 comprising a plurality of ports 153. The elongated spraying
element 151
is coupled to a pressure source 155 (e.g., a pump, air supply, etc.) that
recirculates
clean water (whose flow is indicated by the arrow 56) into the elongated
spraying
element 151, during cleaning only, to create a high energy water spray that
emanates
from each of the ports 153. As shown most clearly in Fig. 9, the direction of
the high
energy spray (indicated by the arrow 157) is from the inside surface 39 to the
outside
surface 37 of the porous member 136. Thus, as the porous member 36 is rotated
(direction indicated by the arrow 161) during cleaning, the high energy spray
drives the
particulate contaminants from the outside surface 39 into the dislodge
subchamber
50B.
It should be understood that the particulate-removing means may
comprise the elongated spraying element 151 alone for driving off the
particulate
CA 02389118 2002-06-04
14
contaminants, or the particulate-removing means may comprise a particulate-
removing
member (e.g., a brush 62 or scraper) in addition to the elongated spraying
element
151, as shown in Figs. 8-9. Together, the elongated spraying element 151 and
the
particulate-removing member (e.g., brush 62 or scraper) act to dislodge the
particulate
contaminants from the outside surface 37 of the porous member 36 during
cleaning.
When the particulate-removing member (e.g., a brush 62 or scraper) is used in
combination with the elongated spraying element 151, the direction of the high
energy
spray (indicated by the arrow 163) may be set to occur after the particulate-
removing
member dislodges some of the particulate contaminants (Fig. 10), thereby
driving
particulate contaminants into the second dislodge subchamber 50B.
The porous member 36, for use in this second embodiment, comprises
an open lower end 137 (Fig. 8) to permit passage of the elongated spraying
element
151 therethrough.
Another variation of the self-cleaning water filter that utilizes a reverse
flow of clean water for cleaning purposes is depicted at 220 in Fig. 14. In
particular,
as indicated by the arrow 165, during normal operation, sea water enters
through an
inlet valve 167 to a water filter 220. During normal operation, a drain valve
171 and
a purge valve 173 remain closed, as will be discussed in detail later. The
water filter
220 comprises a porous member 236, preferably having a wire cloth
configuration.
The direction of the main sea water flow through the porous member 236 is
given by
the arrows 52 and is similar to the flow for the porous members discussed
previously,
i.e., from an outside surface 37 of the porous member 236 to an inside surface
(not
shown) of the porous member 236 and then through the center portion 41 of the
porous
member 236. The cleaned sea water is then passed through an outlet valve 175
in the
direction of the arrow 177.
The cleaning process for the water filter 220 is different from the previous
embodiments in that the porous member 236 does not move during cleaning.
Instead,
a reverse flow of clean water (the direction of this reverse flow is given by
the arrow
179) is injected down through the center of the porous member 236, from the
inside
surface to the outside surface 37 of the porous member 236. This reverse flow
of
clean water impacts the entire inside surface of the porous member 236 and
flows to
the outside surface 37 of the porous member 236, thereby dislodging the
particulate
CA 02389118 2002-06-04
contaminants from the outside surface 37 of the porous member 236. Since this
reverse flow acts through the entire porous member 236, there are no confining
walls
used. Thus, in this embodiment, the particulate removal means comprises only
the
reverse flow of clean water. Because this reverse flow of clean water is
applied
through the entire porous member 236, the water filter 220 must be isolated
from the
normal sea water flow during cleaning, as will be discussed in detail below.
In particular, when cleaning is required, the inlet valve 167 and outlet
valve 175 are closed and the purge valve 173 and drain valve 171 are opened.
The
purge valve 173 is coupled to a clean water reservoir 181 which is under
pressure
(e.g., an air supply, whose input flow is indicated by the arrow 183 and
having a valve
185 for maintaining air pressure in the reservoir 181. The downstream clean
water,
indicated by the arrow 187, enters the reservoir 181 through a recharge valve
189).
When the purge vaive 173 and the drain valve are opened, the reverse flow of
clean
water 179 drives the particulate contaminants off of the outside surface 37 of
the
porous member 236; this reverse flow, now containing the dislodged particulate
contaminants, flows out, as indicated by the arrow 191, through the drain
valve 171.
Once this flow of dislodged particulate contaminants passes to the drain, the
purge
valve 173 and the drain valve 171 are closed and the input valve 167 and the
output
valve 175 are opened, restoring normal sea water flow.
It should be understood that the continuous sea water flow is
accomplished by having a plurality (e.g., five to eight) parallel, non-
rotating filter paths
(not shown) that are coupled to the reservoir 181 through respective purge
valves 173.
Thus, when any one non-rotation filter path is being cleaned using the reverse
water
flow, the remaining parallel channels are operating under the normal sea water
flow.
Another variation of this embodiment, depicted in Fig. 15, uses the
downstream clean water directly to create the reverse water flow. In
particular, the
purge valve 173 is coupled directly to the downstream clean water flow. The
sequence
of valve openings/closings are similar to that described previously. Thus,
when the
purge valve 173 and the drain valve 171 are opened a pressure differential is
created
and the reverse flow of clean water, the direction indicated by the arrow 179,
is
generated directly from the downstream clean water flow.
CA 02389118 2002-06-04
16
Another variation of this embodiment is shown in Fig. 16 that uses
passive components such as a check valve 400 and a flow restricting orifice
402 in
place of the purge valve 173.
It should also be understood that the variations of Figs. 15 and 16, like
that discussed with regard to Fig. 14, also comprise a plurality of parallel,
non-rotating
filter paths that permit the continuous flow of sea water when any one of the
parallel,
non-rotating filter paths is being cleaned by the reverse flow of clean water.
Figs. 17-19 depict an exemplary stationary filter 220', having an
ultrasonic generator 300 disposed therein, that can be used in the systems
shown in
Figs. 14-16 and, more preferably, to the systems of Fig. 15-16.
Before proceeding with a discussion of Figs. 17-19, it should be
understood that in Figs. 14-16, the input flow 165 is shown in an upward
direction from
the bottom of the page toward the outlet flow 177 shown at the top of the
page, for
clarity only. The actual flow of any of the systems shown in Fig. 14-16 is
exemplary
only and may be in any number of directions and, therefore, is not limited to
those
depicted in those figures. Thus, the orientation of the stationary filter 220'
shown in
Figs. 17-19 is simply inverted from that shown in Figs. 14-16. Thus, the "top
surface"
221' in Fig. 17 corresponds to the "bottom" surface 221 shown in Figs. 14-16.
As will also be discussed in detail later, the input line into the stationary
filter 220' is from the side of the canister 26', at an input port 32', rather
than from the
"bottom" surface 221 shown in Figs. 14-16; the reason for this will also be
discussed
later. In addition, a dedicated drain port 376 passes the dislodged
particulate
contaminants away from the stationary filter 220' to a drain (not shown).
Because of
these port configurations, the input tee 291 in the systems of Figs. 14-16 is
eliminated.
As shown in Fig. 17, the stationary filter 220' is housed in the canister
26'. On one side of the canister 26' is the input port 32' while on the other
side of the
canister 26' is the drain port 376; at the bottom of the canister 26' is an
output port 54'.
The ultrasonic generator 300 is disposed inside the hollow interior 41 of the
stationary
filter 220'. The inlet valve 167 is coupled to the port 32' and the drain
valve 171' is
coupled to the drain port 376. The valves 167/171' and the ultrasonic
generator 300
are operated by a controller (not shown) during the cleaning process of the
stationary
filter 220' itself, as will be discussed later.
CA 02389118 2002-06-04
17
As shown most clearly in Fig. 19, the stationary filter 220' is positioned
inside a chamber formed by a circular wall 380. The wall 380 comprises a
plurality of
sets (e.g., eight) of vertically-aligned holes (e.g., '/~" diameter) dispersed
around the
circular wall 380 (see Fig. 17); one hole 382 of each of the plurality of
vertically-aligned
holes is shown in Fig. 19. As will be discussed in detail later, the circular
wall 380 acts
to minimize the effects of the high velocity particulate-contaminated input
flow 165, as
well as to deflect and disperse the flow 165 all around the stationary filter
220'.
The stationary filter 220' comprises three parts: (1) an outer wire cloth
layer 384 (e.g., 5 microns); (2) an inner 40-50 mesh layer 386; and (3) an
inner
perforated metal enclosure 388 (e.g., 16-18 gauge, stainless steel) all of
which are
microwelded together. The perforated metal enclosure 388 comprises staggered
holes
390 (e.g., '/4" diameter, see Fig. 17) that results in an overall surface area
that is
approximately 50-60% open. The outer wire cloth layer 384 filters out the
particulate
contaminants of incoming water/salt water flow that passes through the holes
382 in
the circular wall 380; in particular, as the incoming water/salt water flow
165 passes
through an outer surface 385' (see Fig. 18) of the wire cloth layer 384 to an
inner
surface 385" of the wire cloth layer 384, the particulate contaminants lodge
against the
outer surface 385'. The 40-50 mesh layer 386 disperses the cleaned input flow
around
the periphery of the perforated metal enclosure 388 and through all of the
holes 390
therein. The cleaned water/salt water flow then flows downward through the
hollow
interior 41 of the stationary filter 220' and through the output port 54'.
Although not shown, another version of the stationary filter 220'
comprises only two parts: (1) an outer wire cloth layer (e.g., 5 - 20 microns)
directly
over a wedge wire inner layer with 5/16 inch slot openings between the turns
of wedge
wire. Advantages of this second version of the stationary filter 220' are that
it allows
a 90% open area as well as more direct contact with the backwash flow and the
ultrasonic waves.
As can also be seen most clearly in Fig. 19, several continuous support
members 392 are disposed between the outer wire cloth layer 384 of the
stationary filter
220' and the circular wall 380. These continuous support members 392 form
independent sectors 394 (e.g., eight, Fig. 19) around the periphery of the
wire cloth
layer 384. As mentioned earlier, during normal sea water flow, the effects of
the high
CA 02389118 2002-06-04
18
velocity particulate-contaminated input flow 165 are minimized by the presence
of the
circular wall 380 and the sectorization formed by the continuous support
members 394;
these sectors 394 segment the input flow 165 so that the input flow 165
impacts the wire
cloth layer 384 around the entire stationary filter 220'. In particular, once
the
particulate-contaminated input flow 165 in each sector 394 passes through the
vertically-aligned apertures 382, the input flow 165 encounters the outer
surface 385'
of the wire cloth layer 384 which traps the particulate contaminants therein.
As also
mentioned earlier, the cleaned water then passes through the 40-50 mesh layer
386
which disperses the cleaned input flow around the periphery of the perforated
metal
enclosure 388 and through all of the holes 390 therein. The cleaned water flow
then
flows downward through the hollow interior 41 of the stationary filter 220'
and through
the output port 54'
The stationary filter 220' is releasably secured inside the canister 26'
using four tie bars 396 (Fig. 19) that couple between a lower baseplate 398
and an
upper securement surface 400. To properly seal the stationary filter 220'
inside the
canister 26' an upper annular seal 402 (e.g., rubber, see Fig. 18) and a lower
annular
seal 404 (e.g., rubber) are used.
The ultrasonic generator 300 (e.g., the Tube Resonator RS-36-30-X, 35
kHz manufactured by Telsonic USA of Bridegport, NJ) is releasably mounted in
the
hollow interior 41 of the stationary filter 220'. In particular, an elongated
housing 393
of the ultrasonic generator 300 is suspended in the hollow interior 41 of the
stationary
filter 220'. Thus, when the reverse flow of clean water/salt water 179
occupies the
hollow interior 41, the ultrasonic generator 300 is energized wherein the
ultrasonic
energy is applied to the wire cloth layer 384 in the direction shown by the
arrows 395
through the holes 390. The elongated housing 393 is attached to an electrical
connector 397 which forms the upper portion of the ultrasonic generator 300.
The
electrical connector 397 is then releasably secured to the canister 26' (e.g.,
a nut 399).
A wire harness 401 provides the electrical connection to the ultrasonic
generator 300
from the controller (not shown). In this configuration, it can be appreciated
by one
skilled in the art, that the ultrasonic generator 300 and stationary filter
220' can be
installed/replaced rather easily without the need to disconnect any plumbing
from the
input port 32', output port 54' or drain port 376.
CA 02389118 2002-06-04
19
During normal operation, the inlet valve 167 is open and the drain valve
171' is closed, thereby allowing the contaminated water/salt water flow 165 to
be
cleaned by the stationary filter 220' as discussed above. When the stationary
filter 220'
itself is to be cleaned, the controller (not shown) closes the inlet valve 167
while opening
the drain valve 171'. As a result, a high pressure reverse flow 179 of clean
water flows
from the output port 54' and through the three-part stationary filter 220' and
out through
the drain port 376. As this reverse flow 179 passes through the wire cloth
layer 384, the
particulate contaminants are dislodged from the outer surface 385" of the wire
cloth
layer 384 and then driven out through the drain port 376. It should be noted
that during
this high pressure reverse flow 179, the continuous support members 392 also
act to
prevent the wire cloth layer 384 from separating from under laying support.
The reverse
flow 179 is applied for a short duration (e.g., approximately 4-5 seconds).
At the end of this application, and while there is still clean water in the
hollow interior 41 but where the flow 179 is simply migrating (e.g., movement
of clean
water in inches/minute) rather than flowing, the controller (not shown)
activates the
ultrasonic generator 300 for a longer duration (e.g., 30 seconds to a couple
of minutes)
to provide for further cleaning of the wire cloth layer 384 by using
ultrasonic energy to
dislodge any remaining particulate contaminants in the wire cloth layer 384
into the
migrating water flow and out through the drain port 376.
Without further elaboration, the foregoing will so fully illustrate our
invention and others may, by applying current or future knowledge, readily
adapt the
same for use under various conditions of service.
