AU8421498A - A valve - Google Patents

Description

P/00/01 I Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: A VALVE *a Applicant: PARBURY BUILDING PRODUCTS PTY LTD c i

I

B

4 r -a 2'- "d f~ a -r 'r- The following statement is a full description of this invention, including the best method of performing it known to me: ClNWORDUENNYMmOHNP09304A.OC i;-

A

-a~ r s fl

'P

i 4 ~lt r ;i: iai 7111

:I:

.i 2 A VALVE This invention relates to an improved valve. It relates particularly to a valve which can be used to reduce or eliminate problems associated with water hammer.

When a water tap is turned off abruptly, shock waves can be formed in the water pipe leading to the tap. These shock waves can cause the hammering sound known as water hammer. Water hammer often results in early deterioration of pipes and pipe joints.

Water hammer is a particular problem with electronically operated taps. An example of such an electronically operated tap is illustrated in Figure 1. This particular tap is described in more detail in Australian Patent 662036, the contents of which are incorporated herein by reference. The tap comprises moving valve element 1, valve seat 2, water inlet 3 and water outlet 4. As shown in Figure 1, valve element 1 is seated on valve seat 2, blocking the flow of water between water inlet 3 and water outlet 4.

Pilot water passage 5 communicates between water inlet 3 and pilot ,-eservoir 6. Pilot valve 7 is shown in its closed position against pilot valve seat 8, preventing the escape of water from pilot reservoir 6 to pilot outlet path 9, which communicates with outlet 4.

Pilot reservoir 6 communicates with valve element chamber 10, and when pilot valve 7 is closed water pressure in chamber 10 presses valve element 1 against valve seat 2, preventing the flow of water between inlet 3 and outlet 4.

20 When pilot valve 7 is opened, water pressure in chamber 10 is reduced, allowing valve element 1 to move upwards from valve seat 2, and allowing water from inlet 3 to pass through outlet 4. When pilot valve 7 recloses, water pressure in chamber 10 builds rapidly, and valve element 1 is pressed rapidly against valve seat 2. This rapid closure results in a sudden interruption in the water flow through inlet 3, with the result that Water hammer shock waves may be transmitted up the inlet pipeline from inlet 3.

Water hammer is almost invariably a problem with electronically operated taps.

Manually operated taps, on the other hand, are usually closed by turning a handle, which gradually presses a washer against a valve seat, with the result that interruption in water flow is more gradual and less likely to result in water hammer.

Although the invention is particularly applicable to electronically operated water taps, it is to be understood that the invention is also applicable to other kinds of water valve including manually operated taps, as well as to taps for liquids and gases other than water.

XG Q" Q&61ft1.".Do r According to the present invention, there is provided a valve having: a fluid inlet; a fluid outlet; a valve seat between the inlet and the outlet; a valve element movable between a closed position against the seat, in which communication between the inlet and the outlet is cut off, and an open position away from the seat in which fluid from the inlet may pass through the outlet; a first chamber, communicating with the inlet and located on the opposite S[o side of the valve element from the valve seat, such that fluid in the first chamber urges the valve element towards the valve seat; a second chamber communicating with the inlet and located on the same side of the valve element as the valve seat, such that fluid in the second chamber urges the valve element away from the valve seat; an outlet for the first chamber which may be opened, thereby reducing the pressure exerted by fluid in the first chamber on the valve element, permitting the valve element to move to the open position, and closed, thereby increasing S: 'the pressure exerted by fluid in the first chamber on the valve element, causing the valve element to.move to the closed position; and 0 flow control means between the fluid inlet and the first chamber, allowing a gradual increase of pressure exerted on the valveelement by fluid in the first chamber when the first chamber outlet is closed, so that the valve element moves gradually-to the closed position.

The flow control means may be any suitable means for controlling the flow of fluid between the, fluid inlet and the first chamber. Suitable flow control means include metering Wheels and partially occluded passageways. In a particularly preferred arrangement, the flow control means includes a cooperative arrangement between a component fixed to a wall of the first chamber and a component fixed to the valve element, whereby one or more passageways by which fluid from the-inlet enters the 30 first chamber are partially occluded when the valve element is in the closed position, and :opened when the valve element is in the open position.

In such an arrangement, the wall component and the-valve element component may have any suitable configuration. In an especially preferred configuration, the wall JCGCIy Dos-p bV."DO component is substantially cylindrical and hollow with a closed end and one or more substantially radial bores. The valve element component includes a sleeve which fits over the wall component, leaving a small gap between the two.

In this arrangement, it is preferred that the configuration of the sleeve be such that the radial bores are substantially occluded (apart from the small gap) by the sleeve when the valve element is in the closed position, and substantially open when the valve element is in the open position.

Electronically operated water valves typically have passageways with a minimum diameter of 0.6mm. When the especially preferred arrangement described above is used as a water valve, it is preferred that the radial bores be approximately 0.6mm in diameter, and that the gap between the wall component and the sleeve be approximately 0.1mm. Particles of debris in the fluid stream which are not large enough 1 *to pass through the gap when the bores are occluded by the sleeve can be expelled "i when the valve element is in its open position and the bores are no longer occluded by the sleeve. It is further preferred that a prefilter be installed at the inlet or between the inlet and the flow control means in order to remove debris particles of a size large enough to block any of the parts of the valve.

It is further preferred that the means by which the outlet for the first chamber is opened and closed comprises a bi-stable electronic valve.

The invention will hereinafter be described in greater detail by reference to the attached drawings which show an example form of the invention. It is to be understood that the particularity of those drawings does not supersede the generality of the preceding description of the invention.

Figure 1 is a cross-sectional view of an electronically operated tap of the type S 25 described in Australian Patent 662036, which forms-part of the prior art.

S Figure 2 is a cross-sectional view of a valve according to the present invention. i Figure 3 is an enlarged view of the central portion of Figure 2.

Referring now to Figure 2, the valve of the present, invention has a fluid inlet 11 and a fluid outlet 12. A valve seat 13 is located between inlet 11 and outlet 12. j Valve element 14 is movable between a closed position against seat 13, in which communication between inlet:11 and outlet 12 is cut off, and an open position away from seat 13 in which fluid frominlet 11 maypass through outlet 12.

ry~oc'iPb.trflOC First chamber 15 communicates with inlet 11 and is located on the opposite side of valve element 14 from valve seat 13. Fluid in first chamber 15 urges valve element 14 towards valve seat 13.

A second chamber 16 communicates with inlet 11 and is located on the same side of valve element 14 as valve seat 13. Fluid in second chamber 16 urges valve element 14 away from valve seat 13.

First chamber 15 has first chamber outlet 17, which may be opened, thereby reducing the pressure exerted by fluid in first chamber 15 on valve element 14, permitting valve element 14 to move to the open position away from valve seat 13.

Conversely, outlet 17 may be closed, thereby increasing pressure exerted by fluid in first chamber 15 on valve element 14, causing valve element 14 to move to the closed position, resting against valve seat 13.

Flow control means 18 is located between fluid inlet 11 and first chamber S allowing a gradual increase of pressure exerted on valve element 14 by fluid in first chamber 15 when first chamber outlet 17 is closed, so that valve element 14 moves gradually to the closed position against valve seat 13.

S. Flow control means 18 may include any suitable means for controlling the flow of S water. In the embodiment illustrated, flow control means 18 includes a cooperative S. arrangement between component 19 fixed to the top wall of first chamber 15, and 20 component 20 fixed to valve element 14.

The cooperative arrangement is shown in more detail in Figure 3. Wall component 19 has a hollow centre 21 and a closed end 22, as well as substantially I o radial bores 23. Valve element component 20 has a sleeve 24 which fits over wall component 19, leaving a small gap 25 between the two.

In operation, water flows through inlet 11 into chamber 16, and up through passages 27, 28 and 29 into wall component 19, then out through radial bores 23 into Sfirst chamber 15. From first chamber 15, water flows up through passageway 30 into Spilot reservoir 31. Pilot reservoir 31 drains through pilot valve seat 32 and passageways 33 and 34 to outlet 12.

A pilot valve element (not shown in Figure 2) closes valve seat 32. The pilot valve arrangement may be as shown in Figure 1. When the pilot valve element is removed from valve seat 32, water can flow freely out from first chamber 15 so that the -1 downwards pressure exerted by water in first chamber 15 is less than the upwards C2* o-Pl pressure exerted by water in second chamber 16, so that valve element 14 moves rapidly up and the main valve is rapidly open.

When the pilot valve element is pressed against pilot valve seat 32, water continues to flow into chamber 15 through bores 23, with the result that pressure begins to build up in chamber 15 and valve element 14 begins to move downwards to valve seat 13. However, the flow of water out of bores 23 is constricted by sleeve 24 and only a small gap 25 allows the flow of water. Thus the increase of water pressure in chamber 15 is gradual, with the result that the valve closes gradually.

The smallest diameter of bores in commonly available water valves is 0.6mm. It is preferred that bores 23 be approximately of this size. It is preferred that gap 25 be in the range of from 0.01 to 0.1mm, and more preferably about 0.05mm.

:It is anticipated that small items of debris may not be small enough to pass through gap 25, with the result that they may be caught between bore 23 and gap For this reason, widened portion 26 is provided.

During normal operation radial bores 23 are substantially occluded (apart from small gap 25) by sleeve 24, and valve component 14 never travels sufficiently high to bring radial bores 23 into alignment with widened portion 26, as the exten of upwards travel is limited by an opposing resultant force generated by the imbalance in pressure in chambers 15 and 16 as flow through radial bores 23 increases with approaching 0. 20 alignment with widened portion 26. (Flow through.radial bores 23 increases significantly when they are aligned with widened portion 26.) However, if bores 23 become blocked by small items of debris, the flow of water through them is reduced,- and approaching alignment with widened portion 26 does not cause forces sufficient to prevent further opening, and valve component 14 continues to move upwards until the items of debris which are constricting flow are expelled through widened portion 26. Thereafter, with radial bores 23 fully open, a resultant-force moves valve component 14 back to a position in which bores 23 are occluded by sleeve 24. In this way, the effective size of Sbores 23 (which control the.spread of closure) is reduced, but not at the expense of Sreduced reliability on account of blockage caused by small particles of debris.

When the operating pressure is small, there may be insufficient resultant force to press valve element 14 against seat 13. Accordingly, it is preferred that a spring 35 be f provided to keep valve element 14 in the normally closed position, such that the valve LXGCUILcaisSyDC' L i *T .1 J 7 will open only when water pressure in second chamber 16 is sufficient to overcome the biasing force of spring The various elements in the valve may be made from any suitable material or materials. Especially suitable materials include non-corrosive metals such as brass and non-corrosive plastics. Rubber or flexible plastics or similar materials are suitable for use in places where a firm contact with a valve seat is required, and where a diaphragm type action is required, such as the areas shown in Figure 2 marked in solid black.

It is to be understood that various alterations, additions and/or modifications may be made to the parts previously described without departing from the ambit of the invention.

1i i

Claims (7)

1. A valve having: a fluid inlet; a fluid outlet; a valve seat between the inlet and the outlet; a valve element movable between a closed position against the seat, in which communication between the inlet and the outlet is cut off, and an open position away from the seat in which fluid from the inlet may pass through the outlet; a first chamber, communicating with the inlet and located on the opposite side of the valve element from the valve seat, such that fluid in the first chamber S""':urges the valve element towards the valve seat; a second chamber communicating with the inlet and located on the same 15 side of the valve element as the valve seat, such that fluid in the second -P chamber urges the valve element away from the valve seat; an outlet for the first chamber which may be opened, thereby reducing the pressure exerted by fluid in the first chamber on the valve element, permitting the valve element to move to the open position, and closed, thereby increasing the pressure exertediby fluid in the first chamber on the valve element, causing the valve element to move to the closed position; and flow control means between the fluid inlet and the first chamber, allowing Sa gradual increase of pressure exerted on the valve element by fluid in the first Schamber when the first chamber outlet is closed, so that the valve element moves gradually to the closed position.

2. A valve according to claim 1 wherein the flow control means includes a cooperative arrangement between a component fixed to a wall of the first chamber and a component fixed to the valve element, whereby one or more passageways by which fluid from the inlet enters the first chamber are partially occluded when the valve element is in the closed position;and opened when the valve element is in the open position- jC;GcM*VOol; P 9

3. A valve according to claim 2 wherein the wall component is substantially cylindrical and hollow with a closed end and one or more substantially radial bores, and the valve element component includes a sleeve which fits over the wall component, leaving a small gap between the two.

4 A valve according to claim 3 wherein the configuration of the sleeve is such that the radial bores are substantially occluded (apart from the small gap) by the sleeve when the valve element is in the closed position, and substantially open when the valve element is in the open position.

A valve according to claim 4 wherein the radial bores are approximately 0.6mm Sin diameter, and that the gap between the wall component and the sleeve is Sapproximately 0.1mm.

6. A valve according to any one of claims I to 5 wherein a prefilter is installed at the inlet or between the inlet and the flow control means in order to remove debris particles of a size large enough to block any of the parts of the valve.

7. Avalve substantially as herein described with reference to Figures 2 and 3 of the drawings. DATED: 11 September, 1998 PHILLIPS ORMONDE FITZPATRICK Attorneys For: PARBURY BUILDING PRODUCTS PTY LTD 7 W KII JCG