SELF CLEANING FILTER

Abstract: A self cleaning filter having a hollow element (17) connected through a turbine (16) to a controllable exhaust outlet (13). The fluid flows into the filter (6) and out through an outlet port (5), and on fluid flowing through the exhaust (13) the turbine (16) rotates the hollow element (17), fluid passages (20) connecting the exterior of the filter (6) to the interior of the hollow element (17). The hollow element (17) has the brush (21) pivoted thereto, the brush (21) moving into contact with the filter (6), on rotation of the element (17) by fluid resistance on the brush (21).

Description: Λ SELF CLEANING FILTER " This invention relates to a self cleaning filter such as may be used in an irrigation system. Background of the Invention 5 With the advent of irrigation systems where the irrigation water is sprayed through small nozzles, or where the -irrigation is carried out by drip irrigation, it is essential that the water be filtered before passing to the spray nozzles or drip units 10. otherwise these would readily clog with the particles carried in suspension in the water. Thus it is necessary that filter units be supplied and that some way be provided for effectively cleaning -these filter units. While it is known that filter units 15 can be dismantled and manually cleaned or replaced, this procedure is not entirely satisfactory. Also filtering units are known where a reverse flow can flush the collected filtered material from the filter, this being flushed through an exhaust 20. port. However these re-ty solely on the flow of water and thus an effective cleaning is not always carried out. An example of this has applied to a cartridge of particulate filter medium is shown in Australian Patent No. 420747. 25. U.S. Patent No. 4060483 discloses a method and apparatus for effecting the cleaning of a fluid filter by a hollow filter cleaning body having an inlet situated in close proximity to the filter member, the flow of water through the cleaning body causing movement of the cleaning body, the cleaning water then flowing through an exhaust port. Brief Description of the Invention 5. Thus there is provided according to the invention a self cleaning filter unit, the unit having a liquid inlet and a liquid outlet, a filtering member disposed between said filter inlet and filter outlet, an exhaust outlet, means disposed within said filter unit for 10. moving a filter cleaning element over said filter element to remove filtered material therefrom, brush means pivoted to said filter cleaning element, and means driving said filter cleaning element responsive to flow of fluid from said filter cleaning element 15. through said exhaust, said rotation causing said brush means to contact said filtering member by resistance of water thereon to disturb said filtered material which is passed out of the filter unit through said exhaust. 20. Brief Description of the Drawings In order to more fully describe the invention, reference will now be made to the accompanying drawings in which: FIG. 1 is a longitudinal cross-sectional view 25. of the invention, the filter cleaning element not being sectioned, and FIG. 2 is a cross-section on the lines 2-2 of FIG. 1 on an enlarged scale, Description of -the Preferred Embodiment In a preferred form of the invention the filter unit can comprise a generally cylindrical casing 1 having an inlet 2 and socket 3 toward one end and 5. an outlet 4 and socket 5 toward the other end. Within the casing there is disposed a cylindrical filter element 6, the element being mounted in rings 7 which are sealed by sealing members 8 to the interior of the cylindrical casing 1. The cylindrical filter 10. element 6 is positioned such that the fluid will flow in through the inlet 2 into the interior of the casing at that end and then through the interior of the filter 6, and after passing through the filter element 6 is discharged through the outlet port 4. 15. The inlet flows from the inlet 2 through a course prefilter portion 6a into the interior of the filter 6. The cylindrical casing 1 at the inlet end is closed by an end cap 9 provided with suitable 2 0 . sealing rings 10, the cap being maintained in position by a longitudinal rod 11 passing through the filter unit to be secured to the end cap 12 at the outlet end of the filter unit. This second end cap is provided with an exhaust outlet 13 and sealing rings 10, with 25. the rod 11 supporting on a bush 14 and thrust bearing 15, a water turbine 16 between the end cap 12 and the adjacent ring 7. The water turbine 16 has two arms 17 extending radially, each arm having an aperture 28 so that the water is discharged tangentially to 30. cause the turbine to rotate. This water turbine 16 is connected to a hollow filter cleaning member 17 surrounding said rod and extending through the filter element and supported on the rod 11 by a bush 18 at the ring 7 adjacent the inlet 2 to the casing 1. The hollow member 17 is shaped to have a portion 19 adjacent to the inner surface of the filter 6, where the member 17 is provided with a series of slits, 5. holes or apertures 20. The hollow member 17 is also provided with a longitudinal brush element 21 pivoted from the hollow element by suitable arms 22 or the like. The brush element is adapted to contact the interior of the filter element during the cleaning 10. of the filtered material therefrom. The arms 22 are pivoted in brackets 30 attached by screws 31 to the hollow element 17, the brackets 30 having an upstanding flange 32, the arms 22 passing through holes in the flange 32 in a pivotal manner. 15. A spring 33 having legs 34 attached to the brush 21, has its other leg 35 in contact with the hollow element 17, the spring 33 biassing the brush element 21 away from the filter element 6. A drive housing 23 surrounds the turbine 16, 20. and has a radial wall 24 and a sealing ring 25 to seal the turbine drive area from the filter area except through the hollow member 17. The exhaust 13 can be provided with a suitable flow control, and in normal operation of the filter 25. device this exhaust valve is closed so that the water will flow from the inlet 2 through the interior of the filter element 6 and to the outlet port 4. At this time also the hollow element 17 and the turbine 16 will be filled with water. The thrust bearing 30. 15 crries a disc 26 to help break up the turbulence from the turbine and allow the water to flow through the exhaust. Oi Pl However on opening the exhaust port fluid will flow from the interior of the filter element through the hollow member and through the water turbine to drive the turbine to rotate the hollow 5. element with the brush attached thereto so that the brush then sweeps over the interior of the filter element, the resistance of the water on the brush causing the brush to pivot to contact the filter element. The flow of water as it passes- into the 10. hollow element, through the slots will carry with it the debris and filtered material which has been removed from the filter element by the brush and this material is then discharged to waste through the exhaust port. _, _ The brush is pivoted to the cleaning element so that it protrudes away from the cleaning element and is biassed by the spring to the retracted position away from the filter element when the filter element is not being cleaned. This is to ensure that the 20. brush does not rest in contact with the surface of the cleaning element while it is stationary for there is a tendency for- the brush to become stuck and adhered to the element by accumulated debris. The resistance of the spring is such that it 25. holds the brush in the retracted position, but when the hollow element is rotated, the resistance to movement created by the water causes the brush to pivot into contact with the filter element against the bias of the spring. The spring tension is adjusted so that this occurs, with the spring returning the brush to its retracted position when rotation ceases. The hollow element may have a plurality of apertures therein to allow the water to flow there- 5. through, or could have a longitudinal slit or plurality of slits, which slits can be positioned in relation to the filter and the brush so that as the element and brush rotate the disturbed filtered material and debris would immediately be swept through the 10. slit. The control of the filter unit by the valve positioned in the exhaust aperture or in the exhaust line can be manually operated or alternatively be con¬ trolled automatically either by sensing the back 15. pressure in the filter, or alternatively be controlled by a timer or some other control such as the quantity of water which has passed through the filter. One suitable form of valve is that s'hown in Australian Patent No. -5-08284 entitled "Automatic 20. Filter Backwash Control". The filter element with its sealing rings and the hollow member and the turbine can be readily assembled into the outer cylindrical casing through the ends of the cylindrical casing and are retained 25. in positon by the longitudinal rod and the end caps. It will be realised that various forms of water turbines can be provided, that is being either the reaction or impulse type and either operated by way of the use of curved vanes or jets or the like. c It will be seen that by the action of the brush passing over the filter element that this readily disturbs the collected material therefrom, this not only being suspended particles being carried by the water, but also any accumulated algae or 10. slime or the like which tends to collect on these components. The brush then disturbs these filtered materials and these are then easily carried away by the flow through the exhaust port. This can be carried out during the normal operation 15. of the filter or alternatively the flow through the outlet port can be stopped during the filter cleaning operation but in normal practice the cleaning would take place during the normal operation of the filter. 20. Although one form of the invention has been described in some detail it is to be realised that the invention is not to be limited thereto but can include various modifications falling within the spirit and scope of the invention.

Claims: THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:- 1. A self cleaning filter unit, said unit comprising a cylindrical housing, an inlet at one end of said housing and an outlet at said other end, a circular filter element supported by sealing rings 5 engaging the interior of said housing, characterised by a tubular element supported on a rod extending through said housing and connected to a turbine an exhaust outlet in an end cap adjacent said turbine, a brush element pivoted to said tubular element, 0 said brush being biassed to a retracted position spaced from said filter element. Said tubular element having passages opening into the interior of said tubular element whereby fluid can flow through said inlet into the interior of said filter element through 25 ^ said filter to said outlet, and when said exhaust is open, fluid flows from the interior of said filter element through said openings into the tubular element to said turbine which rotates said tubular element causing said brush element to pivot to be in contact 20. with said filter element by resistance of the fluid on said brush element to .disturb debris which flows with the water through said openings to exhaust. 2. A self cleaning filter element as defined in Claim 1, further characterised in that said brush extends longitudinally of the tubular element, and protrudes from the tubular element in the retracted 5_ position, spring means connected to said brush element and acting on said tubular element, said brush means being mounted on arms pivoted in brackets on said tubular element. OMPI _ WlPθ mm 3. A self cleaning filter unit as defined in Claim 1 further characterised in that said turbine is mounted in a drive housing having a radial wall adjacent the adjacent sealing ring, a further seal sealing said radial wall to said tubular member, said tubular member having a hollow portion passing through said further sealing ring and connected to said turbine. 4. A self cleaning filter unit as defined in Claim 3 further characterised in that said turbine has a pair of hollow radial arms, a tangential aperture in each arm through which water will pass to cause 5. the turbine to rotate. 5. A self cleaning filter unit as defined in Claim 1 further characterised in that said turbine is spaced from the adjacent end cap by a thrust bush carrying a circular baffle. 6. A self cleaning filter unit substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings. OMPI

Inventors: TUCKER ALFRED DENHOLM, TUCKER, ALFRED, DENHOLM
Applicants: RIS IRRIGATION SYST, RIS IRRIGATION SYSTEMS PTY. LIMITED
Application year: 1983
Main classification: B01D35
IPC codes: B01D29