GB2261828A - Pipeline filter - Google Patents

Abstract

A filter for connecting into a pipeline, e.g. upstream of a washing machine water inlet, comprises an open-ended tubular filter element 13 arranged for outward flow. The element is cleaned by diverting the flow from inlet 3 to flush the upstream, interior face of the element. In Fig. 2 this is done by closing upstream valve 20, removing lower threaded plug i 9 and briefly opening valve 20 again. In Fig. 3 there is no valve 20, and plug 19 is replaced by a stopcock which is briefly opened to flush the element. Fig. 4 resembles Fig. 2, but valve 20 is incorporated in main housing 2. <IMAGE>

Description

FILTER DEVICE DESCRIPTION The present invention relates to filters for filtering piped liquids.

In many items of equipment, for example washing machines, dishwashers and drinks vending machines, it is necessary to control the flow of water from a mains supply. Commonly, diaphragm solenoid valves are used for this purpose. However, these valves are very susceptible to malfunction if the water supply is contaminated with particles of dirt. The dirt particles become trapped between the diaphragm and the valve seat resulting in a failure of the diaphragm to fully cut off the flow of water. It is, therefore, necessary to filter the water supply before it enters the equipment.

A known filter is the Filter Ball (Registered Trade Mark) produced by Fratelli Pettinaroli S.p.A. In this product, a thimble shaped mesh filter element is mounted in the ball of a ball valve. In order for the filter to be cleaned the ball valve must be moved to its closed position and a cap removed so that the filter element may be extracted from the ball.

Cleaning of the filter element is effected by passing a high pressure fluid, such as compressed air, in the reverse direction through the filter element.

The filter ball suffers from two disadvantages in that removal of the filter element is a fiddly task and a suitable source of high pressure fluid is required for cleaning. The need for a source of high pressure fluid makes it unsuitable for ordinary domestic use.

It is an aim of the present invention to overcome the aforementioned disadvantages.

According to the present invention, there is provided a filter device for filtering piped liquid comprising means defining a filtering flow path extending from an inlet to an outlet, a filter element located in the filter flow path between the inlet and the outlet, means defining a filter cleaning flow path, and a flow diverting means operable for diverting liquid flowing along the filtering flow path to flow along the filter cleaning flow path.

Preferably, the filter includes sump means for collecting dirt particles wherein the filter cleaning flow path extends through the sump means for removal of collected dirt particles therefrom.

Preferably the filter element is tubular and has a circular cross-section. However other cross-sections may be employed. It is not essential that the filter be tubular and a planar filter element may be employed.

In the event that the filter element is tubular, liquid to be filtered will advantageously pass from the inside of the filter element to its outside.

Conveniently the flow diverting means comprises a threaded plug. Alternatively, it may comprise a stopcock.

Conveniently, the filter further comprises an inflow stopcock for selectively interrupting flow through both the filtering flow path and the filter cleaning flow path.

Conveniently, the filter further comprises a flow regulator for regulating the rate of flow of liquid flowing through the outlet.

Advantageously, the filter element, the inflow stopcock and the flow regulator are housed within a single component of the device.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a side view of a first filter device according to the present invention; Figure 2 is a sectional view of the filter device shown in Figure 1; Figure 3 is a side view of a second filter device according to the present invention; and Figure 4 is a sectional view of a third filter device according to the present invention.

Referring to Figures 1 and 2, a filter housing 1 comprises a first tubular portion 2 having first and second externally threaded ends 3,4. A second tubular portion 5 extends radially outwardly from approximately mid-way between the first and second ends 3,4 of the first tubular portion 2. The second tubular portion 5 is slightly stepped so that its diameter at its free end 6 is greater than its end 7 coupled to the first tubular portion 2. A hollow fillet 8 extends between the second tubular portion 5 and the first tubular portion 1 towards the second end 4 thereof. The free end 6 of the second tubular portion 5 is partially closed by a radially inwardly extending annular flange 9. The annular flange 9 is internally threaded. The passageway through the first tubular portion 2 is bisected by a wall 10 extending thereacross.A flange 11 extending inwardly from the coupled end 7 of the second tubular portion 5 defines a circular aperture 12 coaxial with the second tubular portion 5 in conjunction with the wall 10. Thus a passageway exists along the first tubular portion 2 from its first end 3 through the hole 12 into the second tubular portion 5, and through the hollow fillet 8 to the second end 4 of the first tubular portion 2.

A filter element 13 comprises a cylinder 14 of a metallic mesh having at one end a solid annulus 15 of the same diameter as the mesh cylinder 14 and at the other end an internally and externally threaded coaxial annulus 16. An annular flange 17 extends radially outwardly from the free end of the threaded annulus 16.

The filter element 13 is located coaxially within the second tubular portion 5 such that the outer curved surface of the solid annulus 15 sealingly engages the sidewall of the hole 12 and the threaded annulus 16 threadably engages the flange 9. A plug 18 is threadably engaged within the threaded annulus 16 thus sealing the end of the second tubular portion 5.

A ball valve 20 comprises an annular housing 21 which is externally threaded at a first end 22 for coupling by means of a standard plumbing fitting. The internal diameter of the housing 22 at the first axial extremity 22 conforms to that of a standard plumbing pipe. An annular flange 23 extends radially inwardly from the housing approximately at the inner end of the threaded portion. A central portion of the housing 21 has an internal diameter slightly larger than that of the first end 22. A portion of yet larger internal diameter extends from the central portion 24 to a second end 25. The portion leading to the second end 25 is internally threaded. A ball 24, having a passageway 26 extending diametrically therethrough, is located between the annular flange 23 and a clamping member 27.The clamping member 27 is annular and externally threaded so that it threadably engages the internally threaded portion of the housing 21. The internal diameter of the clamping member 27 conforms to the diameter of the hole 26 through the ball 24. A pair of elastomeric rings are located respectively between the annular flange 23 and the ball 24 and between the ball 24 and the clamping member 27. The ball 24 is rotatable within the housing 21 by means of a screw 24a extending therethrough.

The second end 25 of the housing 21 is provided with flats on its radially facing outer surface to receive the jaws of a spanner and threadably engages the first axial extremity of the filter housing 1.

A flow regulator 29 and a fibre washer 31 are clamped coaxially over the second end 4 of the first tubular portion 2 of the filter housing 1 by means of a clamping piece 30. The clamping piece 30 comprises a stepped annular body internally threaded at its wider end and externally threaded at its narrower end. The clamping piece 30 threadably engages the second end 4 of the first tubular portion 2 of the filter housing 1 to effect clamping the regulator 29 and a fibre washer 31. The fibre washer 31 is sandwiched between the second end 4 of the first tubular portion 2 of the filter housing 1 and the flow regulator 29. The smaller end of the clamping piece 30 is dimensioned for coupling to standard plumbing pipe. The clamping piece 30 is provided with flats on its radial outer surface for receiving the jaws of a spanner.

For operation in a filtering mode the ball valve 20 is as shown in Figure 2. Liquid flows into the filter housing 1 through the ball valve 20, and from the first tubular portion 2 it flows into the inside of the filter element 13 from where it flows radially outward.

The mesh of the filter 13 traps particles of dirt some of which will settle within a sump defined by the portion of the filter element 13 at the free end of the second tubular portion 5 and the plug 19. Liquid flowing from the filter element 13, flows along the hollow fillet 8 back into the first tubular portion 2 and out via the flow regulator 29.

When it is desired to clean the filter 13, the ball valve 20 is closed, by means of the screw 24a, interrupting the flow of liquid through the device.

The threaded plug 19 is then removed. When the plug 19 is removed a small quantity of water will escape bringing with it some dirt particles. However, a large proportion of the collected dirt will remain within the filter either in the sump region or attached to the mesh. Re-opening of the ball valve 20 causes liquid to flow back into the interior of the filter 13. However, since the threaded plug 19 has been removed most of the water flows out through the free end of the second tubular portion 5. If the liquid pressure is sufficient, e.g. mains water pressure, the flow axially through the filter 13 will remove particles of dirt from the mesh and wash any particles collected in the sump region out of the device. Once the filter element 13 has been thoroughly cleaned, the ball valve 20 is shut off again and the threaded plug 19 replaced.

Re-opening of the ball valve re-establishes the filtering operation of the device.

Referring to Figure 3, the ball valve 20 has been omitted and the threaded plug 19 replaced by a stopcock 32. With this arrangement, switching from filtering to cleaning modes is effected simply by opening the stopcock 32.

Referring to Figure 4, both the ball 24 and the flow regulator 29 are incorporated within an enlarged filter housing 1. The first and second ends 3,4 of the first tubular portion 2 are stepped out with respect to the rest of the first tubular portion 2. The free end 3a of the first end 3 is internally threaded. A ball 24 is located within the first end 3 between a pair of elastomeric rings 28, arranged in a similar manner to the equivalent components in the first embodiment described hereinbefore. The ball 24 is retained within the filter housing 1 by means of a first clamping piece 35. The first clamping piece 35 comprises an externally threaded annular member wherein the threads towards one end are arranged to engage those on the first end 3 of the first tubular member 2 of the filter housing 1 and those towards the other end for coupling into standard plumbing pipes.A radially inwardly extending annular flange 36 reduces the internal diameter of the end of the clamping piece 36 inserted into the filter housing 1, to that of the ball 24.

A second clamping piece 37 having substantially constant internal diameter similarly engages the second end 4 of the first tubular portion 2 of the filter housing 1. A fibre washer 31 and a flow regulator 29 are sandwiched coaxially between the filter housing 1 and the second clamping piece 37.

Operation of this embodiment is the same as that described for the first embodiment.

In the embodiments described, the major components are formed from a metal such as brass. However, other materials such as plastics resin material may be employed. Furthermore, whilst reference has been made to standard plumbing fittings and pipes, the invention is equally applicable in situations where other threads or pipe sizes are conventionally employed.

Claims (14)

1. A filter device for filtering piped liquid comprising means defining a filtering flow path extending from an inlet to an outlet, a filter element located in the filtering flow path between the inlet and the outlet, means defining a filter cleaning flow path, and flow diverting means operable for diverting liquid flowing along the filtering flow path to flow along the filter cleaning flow path.

2. A filter device according to claim 1, including sump means for collecting dirt particles wherein the filter cleaning flow path extends through the sump means for removal of collected dirt particles therefrom.

3. A filter device according to claim 1 or 2, wherein the filter element is tubular.

4. A filter device according to claim 3, wherein the filter element has a circular cross-section.

5. A filter device according to claim 3 or 4, wherein during filtering liquid flows from the inside of the filter element through said element to its outside.

6. A filter device according to any preceding claim, wherein the flow diverting means comprises a threaded plug for blocking the filter cleaning flow path.

7. A filter device according to any one of claims 1 to 6, wherein the flow diverting means comprises a stopcock for blocking the filter cleaning flow path.

8. A filter device according to any preceding claim, further comprising an inflow stopcock for selectively interrupting flow through both the filtering flow path and the filter cleaning flow path.

9. A filter device according to any preceding claim, further comprising a flow regulator for regulating the rate of flow of liquid flowing through the outlet.

10. A filter device according to claim 8 wherein the filter element and the inflow stopcock are housed within the same component.

11. A filter device according to claim 9, wherein the filter element and the flow regulator are housed within the same component.

12. A filter device substantially as hereinbefore described with reference to Figures 1 and 2.

13. A filter device substantially as hereinbefore described with reference to Figure 3.

14. A filter device substantially as hereinbefore described with reference to Figure 4.