IL77866A - Back-flushable filter - Google Patents

Description

BACK-FLUSHABLE FILTER MORDEKI DRORI C: 03768 FIELD OF THE INVENTION The present invention relates to filter apparatus generally and more particularly to back-flushable filters.

BACKGROUND OF THE INVENTION Back-flushable filters of various types are well known in the art for a great variety of applications. A particularly successful type of backflushable filter, employing filter disks is described and claimed in the following patents and patent applications of applicant: U.S. Patents 1,026,806 ; 4 , 0M2 , 504 ; 4,045,345 ; 4,271,018 ; 4,295,963 .

SUMMARY OF THE INVENTION The present invention seeks to provide a back-flushable filter, preferably of the disk type, which is suitable for any water filtration system such as that used for a health tub or pool, and is particularly suitable for household use, in that it can readily be cleaned to a pristine state, without substantial disassembly.

There is thus provided in accordance with a preferred embodiment of the present invention, a backflushable filter defining an upstream side arranged to receive a flow of fluid to be filtered from the inlet, and a downstream side arranged to be coupled to the outlet, the filter element being arranged about a longitudinal axis; apparatus for providing a concentrated, relatively high pressure flow of backflushing liquid to the filter element directed from the downstream side to the upstream side and arranged to be movable axially parallel to the longitudinal axis such that the relatively high pressure flow sequentially engages different regions of the filter element for sequential backflushing thereof.

Further in accordance with a preferred embodiment of the present invention, the filter element comprises a generally cylindrical element having an axial central bore along its longitudinal axis which defines the downstream side.

Additionally in accordance with this embodiment of the invention, the apparatus for providing comprises a fluid discharge device arranged for axial movement along the bore in communication with the downstream side.

Further in accordance with an embodiment of the invention, the fluid discharge device comprises fluid driven means for providing rotation of the relatively high pressure flow about the longitudinal axis.

Additionally in accordance with an embodiment of the invention, the fluid discharge device is manually manipulable for providing the axial movement along the bore.

Further in accordance with an embodiment of the invention, the discharge device is normally seated within the .

Additionally in accordance with an embodiment of the invention, the discharge device is provided with valve means which seal the discharge device when it is fully seated within the bore.

Further in accordance with an embodiment of the invention, the filter apparatus comprises a manually operable multi-flow valve having a normal position wherein fluid to be filtered is coupled to the upstream side of the filter element and a backflush position wherein fluid to be filtered is prevented from reaching the upstream side of the filter element and is directed to the means for providing a pressurized flow and wherein a backflush drain communicating with the upstream side of the filter element is coupled for draining to the atmosphere.

Additionally in accordance with an embodiment of the invention, the filter apparatus also comprises a one way valve means permitting high pressure flow to bypass the filter element from the inlet to the outlet.

According to a preferred embodiment of the present invention, the one way valve means comprises a first one way valve such as a pressure valve arranged between the inlet and the downstream side and a second one way valve such as a check valve arranged between the outstream side and the outlet.

Additionally in accordance with an embodiment of the invention, there is provided a filter element comprising a multiplicity of disk-like elements of a porous material separated by a multiplicity of grooved spacer elements, each spacer element Additionally in accordance with a preferred embodiment of the invention, each spacer element defines on a first side thereof axially tapered generally radially extending grooves opening to a downstream side and on a second 3ide thereof axially tapered generally radially extending grooves opening to an upstream side.

Further in accordance with an embodiment of the invention, the grooves on the first and second sides are skewed with respect to each other so as to provide structural strength to the spacer elements .

Additionally in accordance with an embodiment of the invention, the grooves taper downwardly from a maximum adjacent their opening.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be understood and appreciated more fully from the following detailed description taken in conjunction with the drawings in which: Fig. 1 is a side sectional view of filter apparatus constructed and operative in accordance with a preferred embodiment of the present invention; Fig. 2 is a sectional illustration taken along the lines II - II of Fig. 1; Fig. 3 is an enlarged illustration of part of the filter apparatus of Fig. 1 in a somewhat different operating orientation from that illustrated in Fig. 1; Fig. 4 is a side sectional view of an alternative embodiment of filter apparatus constructed and operative in accordance with the present invention; Fig. 5 is a side view sectional illustration of part of the filter apparatus of Fig. 1, taken at 90 degrees to the plane of Fig. 1; Fig. 6 is a sectional illustration of the filter apparatus of Fig. 5 taken along the lines VI - VI; Fig. 7 is a side view sectional illustration of a further alternative embodiment of filter apparatus constructed and operative in accordance with the present invention; Fig. 8 is a pictorial illustration of fluid discharge apparatus useful in various embodiments of the invention seen Fig. 9 is an illustration of two disconnected portions of a still further alternative embodiment of filter apparatus constructed and operative in accordance with the present invention ; Fig. 10 is a pictorial illustration of a portion of a stack of filter disks constructed and operative in accordance with a preferred embodiment of the invention; Fig. 11 is an enlarged illustration of a portion of the stack of filter disks illustrated in Fig. 10; and Fig. 12 is a sectional illustration taken along the lines XII - XII of Fig. 11.

DETAILED DESCRIPTION OF THE INVENTION Reference is now made to Figs. 1 - 3 , which illustrate filter apparatus constructed and operative in accordance with a preferred embodiment of the invention. The filter apparatus comprises a body, generally indicated by reference numeral 10. The body is typically formed of two separate parts, a connection portion 12, and a filter element housing 11. The two parts are typically separable by a user, but need not be so.

The connection portion 12 defines an inlet 16, which is coupled to a supply of fluid to be filtered, and typically is formed with an inner threading 18. Inlet 16 is preferably also provided with an inlet bypass connector 20, whose purpose and function will be described hereinafter. Downstream of inlet 16 there is provided a manually actuable valve 22.

Valve 22 is provided with a handle 24, a valve seat 26, which is preferably integrally formed with the connection portion 12, and a valve stem 28, which is coupled for rotation together with handle 24 with respect to valve seat 26. According to a preferred embodiment of the invention illustrated here, valve 22 comprises a ball or cylinder valve and is best seen from consideration of additional Figs. 5 and 6.

As seen particularly in Figs. 5 and 6, stem 28 is typically of spherical configuration and is formed with a throughgoing bore 30. It will be appreciated that stem 28 may be rotated by handle 24 to assume a selected one of two operating . , . f the bore 30 is positioned to permit direct fluid communication from the inlet 16 to an interior portion 32 of the connection portion 12.

In an alternative operating position, illustrated in Figs. 1, 5 and 6, the bore 30 is at 90 degrees to its position shown in Fig. 3 and blocks fluid communication between inlet 16 and the interior portion 32. In this operating position, the bore 30 provides fluid communication between two fluid connectors 34 and 36, whose purpose and function will be described hereinbelow.

Interior portion 32 communicates with the interior of filter element housing 14, and more specifically with the outer surface 37 of a filter element 38 which is located within housing 14. The outer surface of filter element 38 will henceforth be termed the upstream surface thereof. An inner surface 39 of the filter element 38 will henceforth be termed the downstream surface thereof. It is appreciated that these designations may be reversed for a different flow arrangement through the filter apparatus .

Filter element 38 preferably but not necessarily comprises a stack of filter disks 40 which are held together tightly by ring element 46 which is fixed by a snap connection within housing 14 between disks 40 and end element 42 . End element 42 is an integral part of housing element 14 and presses around ring element 46 so as to hold the filter disks tightly against each other for high performance filtering of relatively small particles. . in applicant's U.S. Patent 4,683,060.

A preferred configuration of filter disks is illustrated in Figs. 10 - 12, to which reference is now made. The assembly shown in these figures comprises alternating centrally apertured disks 10 of a porous material, such as polyester cartridge or polypropylene cartridge or any type of mesh. Disks 10 may be of any preferred thickness so as to provide any desired fineness of filtration.

It is specifically noted that disks 10 may be formed of porous material of any desired characteristics and pass through specifications * and that the term "porous material" as used herein, also Includes screen material of any suitable mesh size. It also includes single or multiple layer porous material with uniform or different pass through characteristics.

Intermediate disks 10 there are provided spacer disks 11 which define axially tapered generally radially extending grooves. It is a particular feature of the present invention, that the generally radially extending grooves are normally not all precisely radial, for reasons which will now be described.

Specifically considering spacer disks 11, it is seen that the disks 11 define two opposite grooved surfaces, which will be termed, for convenience, surfaces 18 and 19. Surface 18 is formed with tapered generally radially extending upstanding 9 I disk and taper to a miniumum adjacent a raised peripheral portion 54 lying alongside the outer edge 56 of the spacer disk.

Surface 49 is formed with tapered generally radially extending upstanding portions 60 which are highest at the outer edge 56 of the spacer disk and taper to a minimum adjacent a raised peripheral portion 64 lying alongide the inner edge 52 of the spacer disk.

In order to provide maximum structural strength to spacer disk 44, it is preferred but not essential that the upstanding portions 50 and 60 which overlie each other are somewhat skewed with respect to each other, such that upstanding portion 50 diagonally overlies upstanding portion 60. This arrangement, enables the thickness of the planar portion 66 of the spacer disk 44 to be made very thin. In this arrangement, one or both of the upstanding portions 50 and 60 are non-radial. Nevertheless, in view of their generally radial orientation, such an arrangement is being defined throughout as providing generally radially extending grooves.

Fig. 12 illustrates the arrangement of a portion of a stack of filter disks as described hereinabove. It is seen that the arrangement is symmetric with respect to upstream and downstream surfaces of a filter element constituted from a stack of such filter disks, in that both surfaces are defined by an array of tapered grooves which serve to collect dirt upstream of the porous disk 40.

Returning now to the connection portion 12, it is seen , which is operative to permit fluid flow from volume 32 to volume 70 only when the differential pressure between volume 32 and volume 70 is sufficient to overcome the biasing of pressure valve 72. Pressure valve 72 does not permit fluid flow from .volume 70 to volume 32 therethrough under any circumstances.

Volume 70 is separated from an outlet 71 by means of a second one-way valve such as check valve 71, which is operative to permit fluid flow from volume "0 to outlet 71 when the differential pressure between volume 70 and outlet 71 is sufficient to overcome the biasing of check valve 7'l. Check valve 71 does not permit fluid flow from volume 71 to volume 70 therethrough under any circumstances. lidably disposed within the body 10 is a manually operable flushing arm 80. Flushing arm 80 defines a fluid inlet 82 which i3 coupled by a flexible conduit (not shown but indicated by dashed lines) to the inlet by-pass connector 20 for receiving a pressurized flow of fluid from the inlet 16.

Arm 80 comprises a sealing collar 81 which is arranged to engage a corresponding fixed collar 86 formed on the bottom surface of filter element housing 11. Typically sealing collar 81 is formed of any desired elastic material . Arm 80 also comprises an enlongate rigid tube 88 at the end of which is defined a discharge portion 90.

The discharge portion 90 may define a desired fluid outlet. According to one embodiment, discharge portion 90 may provide a 360 degree outlet backflushing flow at relatively high filter element. According to an alternative embodiment of the invention, which will be described hereinbelow in connection with Fig. 8, a rotatable directional flow may be provided.

In the embodiment discussed here, as shown in Figs. 1 and 3, the discharge portion 90 is provided with a sealing valve arrangement 92, which seals the discharge portion against fluid communication in either direction, when the arm 80 is fully seated in the body 10, i.e. when the valve 92 is fully seated against surface 94 of the connection portion 12.

A backflush drain 96 is defined by element housing 14 in communication with the upstream surface of the filter element 38 and is provided with a connector 98, which is typically connected, by a suitable conduit, not shown, but indicated in dashed lines, to connector 36. Connector 34 may typically be connected to a backflush drain, which is vented to the atmosphere .

The operation of the apparatus of Figs. 1 - 3, 5 and 6 will now be described briefly. During normal operation of the filter, fluid, typically water to be filtered, enters at inlet 16 and passes via valve 22, in its first operating position shown in Fig. 3 to volume 32, wherein it impinges in a pressurized manner on the filter element 38 at its upstream surface 37. Dirt and other spurious matter filtered from the fluid are retained within filter element 38 and on the upstream surface thereof and the filtered water exits the filter element at the downstream surface which communicates with volume 70 and from volume 70 around check When it is sought to provide an extremely high volume, high pressure flow of water, as for use in a spa or whirlpool bath, pressure valve 72 opens under pressure of the water, providing bypassing of the filter and direct axial throughflow of the water from the inlet 16 to the outlet 71.

When it is sought to clean the filter element, valve 22 is turned to its alternative operating position, as seen in Fig. 1, thus blocking the flow of water from inlet 16 to volume 32. Valve 22 then interconnects connectors 34 and 36 (Fig. 6), thus providing fluid communication from backflush drain 96 to the atmosphere .

Backflush arm 80 may then be unseated from engagement with surface 94, thus causing opening of valve 92 and providing a relatively high pressure backflush flow of fluid received via connector 20 from the inlet 16 in engagement with the downstream surface 39 of the filter element 38. Reciprocal displacement of the discharge portion 90 along axis 100, provides flushing of the entire downstream surface of the filter element 38. The backflushed fluid together with the accumulated dirt and other spurious material is drained through backflush drain 96 to the atmosphere .

Reference is now made to Fig. 4, which illustrates an alternative embodiment of filter apparatus, which represents a simplification of the apparatus of Fig. 1. For the sake of clarity, all elements of the apparatus which are similar in both embodiments are labelled with the reference numerals employed hereinabove. These elements are not described again here for the t!ie use of Valve 22. Accordingly backflush arm 80 is provided with a manually actuable inlet valve 102 which governs the supply x of backfluehing fluid thereto from a pressurized source (not shown). Similarly backflush drain 96 is provided with an outlet valve 104, which governs the outlet of backflush fluid therefrom. It is also noted that the arm 80 is arranged upside down in the arrangement of Fig. 1 a3 compared with the arrangement of Fig. 1. This is not considered to have any particular significance.

During normal filtering operation of the apparatus of Fig. 1, valves 102 and 101 are closed. They are both opened for backflushing operation and the main water supply to the filter inlet 16 is closed.

Reference is now made to Fig. 7, which illustrates a further alternative embodiment of the invention. The embodiment includes both valves 102 and 101 as well a3 valve 22. Here, however, valve 22 doqs not provide connections for the backflush drain as in the embodiment of Fig. 1.

A further additional feature of the embodiment of Fig. 7 is the provision of a rotating, directional backflush discharge head 110, which is shown in plane view in Fig. 8. Head 110 is reciprocated along axis 100 by the movement of arm 80 and provides eccentric, highly directional flow3 of backflushing fluid, which cause rotation of the head in a direction indicated by arrow 112 about axis 100. This arrangement provides enhanced backflushing operation because it employs a highly concentrated 11 element with a flow, which is at higher pressure than a broader flow, as provided by the discharge portion 90 of the embodiment of Fig. 1.

Fig. 9 illustrates a further alternative embodiment of the invention, wherein the filter element housing portion 11 is removable from the remainder of the body for backflushing. A separate backflushing arm 120, typically of the type shown in Figs. 7 and 8 is coupled to a source of backflushing fluid (not shown) and reciprocated along axis 100 to backflush the filter element. In this embodiment, where there is no need for inlet 82 or backflush drain 96, sealing the respective upstream and downstream sides of the filter element with plugs 122 and 124 provides an inexpensive and double-purpose use of the same filter element .

It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention is defined only by the claims which follow:

Claims (17)

C L A I M S

1. A backflushable filter defining an inlet and an outlet and comprising a filter element defining an upstream side arranged to receive a flow of fluid to be filtered from the inlet, a downstream side arranged to be coupled to the outlet, the filter element being arranged about a longitudinal axis; and means for providing a concentrated, relatively high pressure flow of backflushing liquid to the filter element directed from the downstream side to the upstream side and arranged to be movable axially parallel to the longitudinal axis 3uch that the relatively high pressure flow sequentially engages different regions of the filter element for sequential backflushing thereof.

2. Apparatus according to claim 1 and wherein said filter element comprises a generally cylindrical element having an axial central bore along its longitudinal axis which defines the downstream side.

3. Apparatus according to either of the preceding claims and wherein said means for providing comprises a fluid discharge device arranged for axial movement along the bore in communication with the downstream side.

4. Apparatus according to claim 3 and wherein said fluid discharge device comprises fluid driven means for providing rotation of the relatively high pressure flow about the longitudinal axis.

5. Apparatus according to either of claims 3 and 4 and wherein said fluid discharge device is manually manipulable for providing the axial movement along the bore.

6. Apparatus according to any of claims 3 - 5 and wherein the said discharge device is normally seated within the bore.

7. Apparatus according to any of claims 3 - 6 and wherein said discharge device is provided with valve means which seal the discharge device when it is fully seated within the bore.

8. Apparatus according to any of the preceding claims and also comprising a manually operable multi-flow valve having a normal position wherein fluid to be filtered is coupled to the upstream side of the filter element and a backflush position wherein fluid to be filtered is prevented from reaching the upstream side of the filter element and is directed to the means for providing a pressurized flow and wherein a backflush drain communicating with the upstream side of the filter element is coupled for draining to the atmosphere.

9. Apparatus according to any of the preceding claims and also comprising a one way valve means permitting high pressure flow to bypass the filter element from the inlet to the outlet.

10. Apparatus according to claim 9 and wherein said one way valve means comprises a first one way valve arranged between the inlet and the downstream side and a second one way valve arranged between the upstream side and the outlet.

11. A filter element comprising a multiplicity of disk-like elements of a porous material separated by a multiplicity of grooved spacer elements, each spacer element defining axially tapered generally radially extending grooves.

12. A filter element according to claim 11 and wherein each spacer element defines on a first side thereof tapered generally radially extending grooves opening to a downstream side and on a second side thereof tapered generally radially extending grooves opening to an upstream side.

13. A filter element according to claim 12 and wherein said grooves on the first and second sides are skewed with respect to each other so as to provide structural strength to the spacer elements .

14. A filter element according to any of claims 11 - 13 and wherein said grooves taper downwardly from a maximum adjacent their opening.

15. Apparatus according to any of claims 1 - 10 and wherein said filter element is constructed according to any of claims 11 - 14.

16. Apparatus substantially as shown and described

17. Apparatus substantially as shown in any of the drawings . For the applicant, Advocate and 03768 I