WO1993010879A1

WO1993010879A1 - Ceramic filter

Info

Publication number: WO1993010879A1
Application number: PCT/AU1992/000646
Authority: WO
Inventors: Ronald William Arthur
Original assignee: MURASAP INDUSTRIES Ltd
Current assignee: MURASAP INDUSTRIES Ltd
Priority date: 1991-12-03
Filing date: 1992-12-03
Publication date: 1993-06-10
Anticipated expiration: 1994-06-03

Abstract

A filter assembly (10) is provided which is configured to be automatically self-cleaning and which may be used for a variety of filter processes and fluids. A filter assembly comprises a body (11, 12) which contains filter elements (21), typically ceramic or sintered microporous material configured in a cylindrical shape to have a fluid, generally water, pumped from the outside of the cylinder to its inside, thereby providing filtered water but which accumulates debris on the supply side of the filter. A plurality of filter elements (21) are contained in an apertured sleeve (22) which support a debris removal member which comprises a pad holder (25) and a scrubbing pad (23) biased against the debris accumulation side of the filter elements (21). Driving gears (28) are provided at the ends of the apertured sleeve (22) to allow them to be rotated by electric or other motive force so that the scrubbing pad (23) abrades the debris accumulation side of the filter element (21), while supply water is pumped into and out of the supply side of the filter elements (21) of the filter assembly (10). The operation of the scrubbing action can be initiated periodically or as a result of the detection of such characteristics as reduced flow, increased pump pressure or actual debris build-up on the filter element surface.

Description

"CERAMIC FILTER"

This invention relates to a filter assembly and in particular a filter assembly of the self-cleaning type which may be used to filter drinking water however this is not the only fluid that may be used in such an assembly.

BACKGROUND

Filters are available which have the facility to filter out virus and bacteria from water and other fluids and thereby purify it for consumption and/or various industrial uses. Notwithstanding the availability of such filters, filters capable of performing these functions have previously used osmotic filter films and these are very fragile and expensive to replace.

Furthermore, difficulties are encountered when the filter material is ceramic and heretofore the build-up of material and debris on the surface of the filter has been cleaned by hand. This requires dismantling the filter assembly so that access to the filter materials can be gained or alternatively removed for hand cleaning. This previous method is expensive in time and constitutes a disruption to the serviceable time of the filter assemblies which is particularly expensive if it disrupts industrial processes.

With the object of providing a filter which is adapted for automatically cleansing itself, in an embodiment of this invention a filter assembly comprises at least one filter element, at least one debris removal member biased with biasing means against a debris accumulation surface of said filter element located such that with relative movement between said filter element and said debris removal member, debris is removed from the accumulation surface of said filter element.

In a further aspect of the filter assembly, the filter element is annular in shape and located co-axial of an annular apertured sleeve and at least one debris removal member is attached to said sleeve and biased against said filter element. In yet a further aspect of the filter assembly there exists a driving means for rotating said sleeve with respect to said filter element.

A further aspect of the filter assembly comprises a timing means adapted to actuate the driving means after a predetermined time.

Yet a further aspect of^" the filter assembly comprises a fluid flow measurement means for measuring the flow of fluid through the filter assembly and further adapted to actuate the driving means after measuring a predetermined minimum flow.

In another aspect of the invention a method of cleaning a filter assembly which further comprises an outlet valve located so as to allow fluid on the accumulation surface side of the filter element out of the filter assembly, the method comprises the steps of (a) actuating said driving means and (b) opening said outlet valve, while pumping fluid into said filter assembly so that debris flows out of the outlet valve of the filter assembly and the pumped fluid only contacts the accumulation surf ce of the filter means.

While the invention need not necessarily include the abovementioned details, an embodiment is described in some further detail with reference to and is illustrated in the accompanying drawings in which:

DETAILED DESCRIPTION OF THE DRAWINGS Fig 1 is a top view of a filter assembly according to • this invention;

Fig 2 is a partial sectioned side view of Fig 1 taken on line 2-2 of Fig 1;

Fig 3 is a section taken on plane 3-3 of Fig 2; and Fig 4 is.a fragmentary section taken on plane 4-4 of Fig 2, but drawn to a much larger scale.

DETAILED DESCRIPTION OF THE INVENTION

In this embodiment a filter assembly 10 comprises a housing having a cylindrical side wall 11 and dome shaped end caps 12. There are provided upper and lower plates 13 and 14, respectively within the housing and displaced from respective ends, the upper plate having a central aperture which receives a tension bolt 15 which is coupled to a tension spring 16 and the upper plate is movable so that it becomes a pressure plate. The lower plate 14 however is carried on an upstanding hollow stem 18 which extends upwardly from the lower end cap 12, and the stem 18 is perforate at 19 to open into a manifold 20 which is in communication with the lower ends of each of a plurality of ceramic filter elements 21.

Each filter element 21 is contained within a respective apertured protective sleeve 22 (shown in most detail in Fig 4) and the sleeves 22 constitute a fixing point for at least one debris removal member, comprising in this embodiment a filter scrubbing pad holder 25 and a scrubbing pad 23. Each scrubbing pad 23 comprises a pad of abrasive cleaning material, in this embodiment being an abrasive pad sold under the registered trade mark SCOTCH BRITE.

It will be understood that the choice of roughness of the pad is dependant upon the degree of acceptable wear produced each time the scrubbing action occurs. Ideally the filter element and any covering it may have will be cleaned but not detrimentally worn however in using the term abrasive some acceptable degree of wear is expected.

Each scrubbing pad 23 is carried on the pivoting arm pad holder 25 which itself projects from a pivot pin 26 which is pivoted between the end plates 27 at the lower and upper ends of the filter element 21. Typically, the filter element may comprise a ceramic medium of suitable porosity to restrict the passage of debris and foreign matter which may be as small as 0.2 to 0.3 microns. However, the filter element may also comprise sintered material with similar porous and filtering characteristics.

The end plates 27 are located in the ends of and fixed with respect to the sleeves 22, so as to rotate with them and this rotation is effected by each of the sleeves having attached to one end thereof a gear. When the gears are inter- meshed as depicted in Fig 3, a train of gears is provided and includes a driving gear 28 which engages with one of the plurality of„ inter-meshing gears 29, such that, when the driving gear is actuated the inter-meshed gears are driven to thereby rotate respective sleeves 22.

The driving gear may be driven by an external motor coupled to the driving shaft ^'30 which extends through the upper end of the end cap 12.

In lieu of an external motor, use may be made of a water turbine, or a series of turbines, actuated by water flow within the housing.

In either configuration the driving means may be selectively actuated by manual means or motorised driving forces, or control of when the driving means is actuated, may be achieved by a timing means. Ideally, the timing means is set to operate at preset times of the day, preferably, when the filter assembly is not being used or during low activity periods of the industrial environment in which the filter assembly is being used.

Each filter element may preferably be a single length of annular material but may also comprise a plurality of annular filter elements which are aligned end to end and the interconnection between each adjacent filter element is a sealed interconnection so that fluid does not have a path of lesser resistance to travel.

As the sleeves 22 are rotated, pressure is maintained between the pads 23 and the outer surfaces of the filter element 21, and this is effected by a bias means comprising in this embodiment a helical coil torsion spring 32 arranged as shown in Fig 4. Upon rotation of the sleeves 22, scrubbing pads 23 traverse the circumference of the respective filter elements 21, and alternatively, the holders for the pads 23 need not necessarily be associated with the perforate sleeves 22. The driving of the sleeves 22 requires some pressure to be retained between the pads 23 and the outer surfaces of the filter element 21, and this is effected by helical coil torsion springs 32 arranged as shown in Fig 4.

Upon rotation of the holder sleeves 22, the scrubbing pads 23 traverse the circumferences of the respective filter elements 21.

It is preferable, although not essential, to flush the debris accumulation surface of the filter element during the process of removal of debris from said surface. Therefore, an outlet valve (not shown) is located on the filter assembly so as to allow fluid on the accumulation surface side of the filter element, out of the filter assembly. A method of cleaning the filter assembly, which preferably is accomplished using infiltrated water although unfiltrated water can be used, and is achieved by actuating the driving means to remove debris from the accumulation surface of the filter element while opening the outlet valve during pumping of infiltrated fluid (water) into the filter assembly, so that debris flows out of the outlet valve of the filter assembly and the pumped fluid only contacts the accumulation surface of the filter means .

Actuation of the driving means (also not shown) during back flushing may also be used.

A further alternative control mechanism for the onset of the operation of the driving means may be through the use of a pressure sensor which is responsive to the pressure of the filtered fluid exiting from rhe filter assembly. In this example a predetermined minimum flow pressure of filtered water from the filter assembly is representative of a filter which has reduced in its efficiency as the debris builds up on the filter element.

It will also be appreciated that the filter assembly is not restricted in its use to the filtration of water for domestic and industrial uses and the invention provides automatic cleansing of filter assemblies of many types and configurations.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A filter assembly comprising at least one filter element, at least one debris removal member biased with biasing means against a debris accumulation surface of said filter element located such that with relative movement between said filter element and said debris removal member, debris is removed from the accumulation surface of said filter element.

2. A filter assembly according to claim 1 wherein said filter element is annular in shape and located coaxial of an annular apertured sleeve and said at least one debris removal member is attached to said sleeve and biased against said filter element.

3. A filter assembly according to claim 2 further comprising driving means for rotating said sleeve with respect to said filter element.

4. A filter assembly according to claim 2 wherein a plurality of said cylindrical filter elements and respective sleeves, are circumferentially spaced having parallel axes, said sleeves further comprise a gear element fixed with respect to said sleeve at an end thereof and arranged so that said gears are inter-meshed such that when one gear element is driven other gears are also driven.

5. A filter assembly according to claim 1 wherein said debris removal member comprises a scrubbing pad holder adapted for holding a scrubbing pad of an abrasive material located in scrubbing contact with said filter element.

6. A filter assembly according to claim 5 wherein said scrubbing pad is mildly abrasive with respect to said filter element.

7. A filter assembly according to claim 1 wherein said bias means comprises a spring fixed at one end to said sleeve and arranged to urge at its other end said debris removal member against said filter element.

8. A filter assembly according to claim 3 wherein said driving means comprises a turbine actuated by fluid flow within the housing.

9. A filter assembly according to claim 1 wherein said filter element is comprised of sintered material having micro-porous properties.

10. A filter assembly according to claim 1 wherein said filter element is comprised of ceramic material.

11. A filter assembly according to claim 3 further comprising a timing means adapted to actuate said driving means after a predetermined time.

12. A filter assembly according to claim 3 further comprising a fluid flow measurement means for measuring the flow of fluid through said filter assembly and further adapted to actuate said driving means after measuring a predetermined minimum flow.

13. A method of cleaning a filter assembly according to any preceding claim which further comprises an outlet valve located so as to allow fluid on the accumulation surface side of the filter element out of the filter assembly, said method comprising the steps:

A. actuating said driving means, and

B. opening said outlet valve, while pumping fluid into said filter assembly so that debris flows out of the outlet valve of the filter assembly and the pumped fluid only contacts the accumulation surface of the filter means.