AU2018260842B2

AU2018260842B2 - Diaphragm valve sealing arrangement

Info

Publication number: AU2018260842B2
Application number: AU2018260842A
Authority: AU
Inventors: Philip John Collins
Original assignee: Hansen Developments Ltd
Current assignee: Hansen Developments Ltd
Priority date: 2010-06-04
Filing date: 2018-11-07
Publication date: 2020-03-12
Anticipated expiration: 2031-06-03
Also published as: AU2018260842A1; AU2017201478A1; AU2015227545A1

Abstract

: The invention relates to a diaphragm valve and in particular to a guiding assembly for a diaphragm element within the valve and to a float type valve and in particular to a sealing 5 arrangement for the valve. The guiding assembly of the invention comprises a guide pin and a guide bush of harder material than the soft diaphragm to reduce friction as the diaphragm moves up and down the pin to close and open the valve. The sealing arrangement of the invention comprises a rim about a hole in the valve body where the float arm seal opens and closes the valve for reducing or eliminating potential water hammer issues during wave action. 10 tooo 12-2 A CA

Description

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A CA DIAPHRAGM VALVE SEALING ARRANGEMENT

FIELD OF THE INVENTION The invention relates to a sealing arrangement for a valve and in particular a float type diaphragm valve.

BACKGROUND OF THE INVENTION Diaphragm valves of various types are known and used in various applications. US patent 6,374,855 describes one form of diaphragm valve. It is desirable to improve the functionality of such commonly used valves.

Float valves of various types are also known and used in applications where water level needs to be maintained, such as in water troughs.

It is therefore an object of the present invention to provide an improved or at least alternative form of diaphragm valve, and/or to provide an improved or at least alternative form of float valve.

STATEMENTS OF THE INVENTION In a first aspect the invention may broadly be said to consist of a float valve comprising: a valve body having a hollow interior, an inlet port to connect a hydraulic or pneumatic system to the interior of the body of the valve, an outlet port for fluid flow from the interior of the body of the valve, a diaphragm movably mounted within the interior of the valve body and normally closing the inlet port, an opening to communicate fluid pressure from the interior of the body of the valve on an inlet port side of the diaphragm, into a cavity on an opposite side of the diaphragm, such that when fluid pressure on said opposite side of the diaphragm falls below fluid pressure on the inlet side of the diaphragm, the diaphragm will move to open the interior of the valve to fluid flow through the valve from the inlet port to the outlet port, and will move to close the interior of the valve to fluid flow through the valve when fluid pressure on said opposite side of the diaphragm is equalised with fluid pressure on the inlet side of the diaphragm, a hole from the interior of the valve on said opposite side of the diaphragm, to an exterior

of the valve, a float arm pivotally coupled at one end of the float arm to the valve body adjacent the hole and adapted at an opposite end of the float arm to be coupled to a float, a rim projecting about the hole from the interior of the valve on said opposite side of the diaphragm to an exterior of the valve, and at least one rim opening through a side wall of the rim, and a compressible sealing member carried by said one end of the float arm to move with the float arm, which sealing member does not contact the rim in a position of the float arm which fully opens the valve, contacts the rim without closing the rim opening in an intermediate position of the float arm which also fully opens the valve, and is sufficiently compressible to contact and compress against the rim to close the rim opening in another position of the float arm which closes the valve.

Preferably the rim comprises multiple rim openings through the side wall of the rim around the rim.

Preferably the sealing member is formed from a rubber material.

The term "comprising" as used in this means "consisting at least in part of'. When interpreting each statement in this specification that includes the term "comprising", features other than that or those prefaced by the term may also be present. Related terms such as "comprise" and "comprises" are to be interpreted in the same manner.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will be described by way of example only and with reference to the drawings, in which:

Figure 1 is a perspective view of a first embodiment of a diaphragm valve,

Figure 2 is a cross-sectional view of the valve of figure 1 shown in the closed position,

Figure 3 is a cross-sectional view of the valve of figure 1 shown in the open position, and

Figure 4 is an enlarged view of the guiding assembly of the valve of figure 2,

Figure 5 is a cross-sectional view of an embodiment of the valve of figure 1 employing a biasing spring and a preferred sealing arrangement of the invention and shown in the open position,

Figure 6 is a cross-sectional view of the valve of figure 5 shown in the open position with the float arm pivoted towards the closed position due to wave action,

Figure 7 is an enlarged view of the sealing arrangement of the valve in figure 6,

Figure 8 is a cross-sectional view of the valve of figure 5 shown in the closed position, and

Figure 9 is an enlarged view of the sealing arrangement of the valve in figure 8.

DETAILED DESCRIPTION Referring to figure 1 a diaphragm valve 100 is shown. The valve 100 is a float type valve having a main body 10 and a float arm 20 coupled to the main body 10 and a diaphragm assembly within the body 10 for actuating the valve 100, to open and close the fluid path between inlet and outlet ports 11 and 12 respectively.

Referring now to Figures 2 and 3, the main body 10 has a hollow interior 15, an inlet port 11 by which the diaphragm valve 100 may be connected to a pipe system from a fluid supply under pressure for example, and an outlet port 12 which may also connect to a pipe system or directly communicate with a trough or reservoir for example. The inlet port 11 is formed by an aperture at end 10a of the body opposite end 10b. The aperture is internally threaded so that the valve 100 may be threaded onto the end of a pipe for example so that the end of the pipe communicates through the inlet port 11 and into the interior 15 of the valve 100. Outlet port 12 is provided for the exit stream of fluid from the interior 15 of the body 10 of the valve 100. Fluid will enter through inlet port 11 and flow through the interior 15 of the valve 100, exiting via outlet port 12 only when the valve 100 is open (as shown by stream C in figure 3). When the valve 100 is closed, the fluid path is obstructed and the outlet port 12 is closed so no fluid exits the valve 100.

A circular wall 30 extends from the inlet port 11 into the interior 15 of the valve as shown, and terminates at one end to form a valve seat 11a. A diaphragm 7 is mounted within the interior 15 of the valve. In the preferred form the diaphragm 7 is generally circular, and comprises a thin annular skirt 7a which extends from the periphery of the side wall 7b of the preferred form diaphragm 7 as shown. The distal edge 7c of the skirt 7a and the inner surface of end 10b both comprise complementary formations 8 (such as a recess at the inner surface of end 10b for receiving distal edge 7c) for retaining the distal edge 7c against/within the inner surface of end 10b. In the preferred embodiment shown, the hollow body 10 comprises a main body component 10 and a cap element 29 mounted at end 10b of the body 10. The cap element 29 having a formation 8 formed on the inside face for retaining the diaphragm 7. The cap element 29 in the preferred embodiment is shown as two separate components, a cover 29a engaging the main body component 10 at end 10b and a cap 29b threadably engaging the main body component 10 over the cover 29a to retain the cover at end 10b. In an alternative embodiment however the cap element 29 may be a single component. The cover 29a and cap 29b will be referred to as cap or cap element 29 from here onwards.

The skirt 7a is a thin, flexible skirt which can flex and fold to allow the diaphragm 7 to move between the position shown in figure 2 where the diaphragm 7 seals against the seat 11a to close the outlet port 12, and the position shown in figure 3 where the diaphragm 7 has moved towards the cap 29 to open the port 12, to the interior 15 of the body 10.

The diaphragm 7 is preferably a separately moulded plastic component which is simply fitted to body 10 so that the edge 7c of the skirt 7a of the diaphragm 7 enters into the annular formation 8 in the body and the diaphragm 7 is not secured by screws or clamps or similar. This provides for easy assembly and a simple construction and moreover it has been found that the diaphragm 7 will effectively seal for both vacuum and pressure, up to relatively high pressures.

In one form, the diaphragm 7 including the integral skirt 7a are formed from a soft plastics material and the diaphragm 7 has a side wall 7b and an annular flange 7d extending inwardly from the side wall 7b for receiving an annular member/insert 17 of harder material. The annular flange 7d having an orthogonal base and wall structure for receiving an end of member 17 therein. The member/insert 17 has a similar profile to the diaphragm 7 to allow the diaphragm 7 to lie against the member/insert 17 as shown and move up and down the body 10 with the member 17 to open and close the valve 100. Member/insert 17 aids the soft diaphragm 7 in keeping its structure as it moves up and down the body 10. However member/insert 17 is only a preferable feature and may not be employed in some embodiments. Another annular member 18 fitted or otherwise integrally formed within the main body 10 of the valve 100 engages an upper surface of a flange 7e extending from the end 7c of the skirt 7a above the annular formation 8 to hold the flange 7e against the formation 8 and allow the thin skirt 7a to fold/flex to move the diaphragm 7 to open the valve 100 as shown in figure 3.

In the preferred embodiment, the diaphragm 7 is formed from a rubber material and over moulded onto the annular member/insert 17.

A guide member 22 extends centrally from the cap 29 through an aperture or opening 21 in the centre of the diaphragm 7 and towards the port 11. The guide member 22 may be formed as a separate component from the body 10 and received within a recess 23 of the cap 29 as shown. In the preferred form the guide member is a cylindrical pin 22. Referring now to Figure 4, a guide bush 24 is accommodated within the opening 21 at end and has a main body component 24a inside the diaphragm 7 and a flange 24b at an end of the body 24a engaging the end of the diaphragm at opening 21. The guide pin 22 extends through the centre of the bush 24 as shown. The bush 24 around the pin 22 is slightly larger than the diameter of the pin 22 and forms a channel 26 through the diaphragm from the port 11 to the cavity or space 25 behind the diaphragm (shown in Figures 2 and 3), between the rear side of the diaphragm and the cap 29 of the body. The guide bush 24 is formed from a harder material than the soft diaphragm 7 to thereby reduce friction as the diaphragm 22 moves up and down the pin 22. Preferably the guide bush 24 is formed from a plastics material. The guide bush 24 may be formed separately or integrally moulded with the diaphragm and/or member/insert 17.

The guide pin 22 is preferably of a length such that it extends past the bush 24 and opening 21 when the diaphragm 7 is in the open and closed positions (as shown in figure 4). For example, the pin 22 may extend 1-1.5mm past the bush 24 when the diaphragm is in the closed position. This arrangement helps prevent the channel 26 from getting blocked. As the pin 22 is always protruding through and out the bush 24, it will act to push any debris out and away from channel 26 when the diaphragm moves along the pin 22. Furthermore, the guide bush 24 is preferably only slightly larger than the pin 22 to prevent large particles from getting into and blocking the channel 26. This small size difference means only small debris particles can enter through channel 26 which also prevents hole 27 through cap 29 from getting blocked due to the relative size difference between the channel 26 and the hole 27 (explained in more detail further below).

Referring now also to Figures 2 and 3, the preferred form valve shown has a hole 27 formed through the cap 29 adjacent the cavity 25. Hole 27 when opened enables fluid to flow from the cavity 25 to the exterior of the valve and is sized to allow greater flow than through the channel 26. A seal 28 at the end of the float arm 20 is situated adjacent the hole 27 to open and close the hole 27 with pivotal movement of the arm 20. Seal 28 is preferably made of rubber to provide the necessary sealing against hole 27 when the valve 100 is closed.

In operation, when the float arm 20 pivots to the open position shown in figure 3 there will be a reduction in pressure via the hole 27 in the cavity 25 behind the diaphragm 7 and relative to the inlet port side of the diaphragm 7. This relative pressure imbalance will cause the diaphragm 7 to move towards the cap 29 from the position shown in figure 2 to that shown in figure 3, thus opening the outlet port 12 to the interior 15 of the body 10 to allow fluid to pass from the inlet port 11 through to the outlet port 12 as indicated by arrow C. Fluid from the inlet port 11 will operate against the top surface of the diaphragm 7 to move the diaphragm towards cap 29 further thereby increasing fluid flow through the valve 100.

When the float arm 20 pivots to the closed position as shown in figure 2, fluid flow through hole 27 will be prevented/blocked off causing pressure within the cavity 25 to build up through channel 26 to thereby equalise with the inlet port side of the diaphragm 7. This equalisation of pressure alongside the natural resilience of the thin flexible skirt 7a of the diaphragm will cause the diaphragm 7 to move back up to its original position against seat 11a to close the outlet port 12 off from the inlet 11 as shown in figure 2.

The hole 27 is sized to allow greater fluid flow than through channel 26. Guide bush 24 aids with this requirement by providing an aperture at opening 21 that is only slightly larger than the diameter of the guide pin 22. Channel 26 will therefore have a small width to restrict flow from the inlet side of the diaphragm to the cavity 25 to enable pressure reduction in the cavity 25 when the valve 100 (and hole 27) is opened. For example the diameter of channel 26 may be approximately 1.9mm, the diameter of the guide pin may be approximately 1.6mm and the diameter of the hole 27 may be approximately 1.9mm. These dimensions are only exemplary and are not intended to be limiting.

For the float type valve of the preferred embodiment, the float arm 20 is generally connected to a float element (not shown) arranged to float within a fluid reservoir such as a water trough for example. As the level of fluid in the reservoir lowers, the float element pulls the float arm 20 which unblocks hole 27 and causes the valve 100 to open. Water can then flow from an external source through inlet 11 and out port 12 into the trough. Once the desired level is reached, the weight of the float element no longer forces the float arm 20 to pivot downwards which then causes the float arm 20 to pivot back and block the hole 27 to close the valve 100.

As shown in the figures, the pin 22 is of a constant diameter throughout its length. In an alternative embodiment however, the pin 22 may be formed with a varying diameter along its length. For instance, the diameter of the pin 22 may decrease at the lower portion adjacent the bush 24 when the diaphragm 7 is in the open position. This means the width of channel 26 will increase when the diaphragm 7 moves to the open position. When the valve 100 is caused to close, the increased size of channel 26 will allow a greater flow of fluid through to the cavity 25 allowing a faster pressure build up behind the diaphragm 7 and thereby speeding up the closing action of the valve 100. The diameter of the pin 22 will be greater at the upper portion adjacent the bush 24 when the diaphragm 7 is in the closed position, decreasing the width of the channel 26 relative to hole 27 to prevent blockage and enable proper operation of the valve 100 as described above.

Referring to figures 5 and 8, in one embodiment the valve 100 further comprises a spring element 40 or other biasing means fitted between the diaphragm 7 and the cap 29 in cavity 25 to assist in moving the diaphragm towards the closed position. Figure 8 shows the spring element 40 in a less compressed/relaxed state and pushing the diaphragm 7 (and in particular acting on the relatively harder member 17) up against the valve seat 11a to close the valve 100. Figure 5 shows the valve 100 in the open position, with the member 17 acting against the top of the spring 40 to compress the spring 40 and thereby bias the diaphragm 7 towards the closed position.

Diaphragm valves of the invention may be formed in large and small sizes. Because the valve comprises relatively few components it is inherently robust and reliable in operation, and all the components of the valve maybe formed by injection moulding, or by metal casting for larger versions if desired.

Wave action within a reservoir can disrupt the operation of a float valve. This wave action could be caused by wind, by water flow from the valve outlet or by stock drinking from the trough for example. This causes the float to move up and down uncontrollably which could in turn cause the float arm 20 to move and the seat/seal 28 to open and close the hole 27 in the body of the valve 100. Consequently, this results in the diaphragm 7 opening and closing the valve 100 rapidly leading to potential water hammer issues.

Referring now to figures 5-9 a sealing arrangement (generally indicated as 50 in figures 5, 6 and 8) about hole 27 is shown, according to the invention. The particular sealing arrangement 50 dampens the rapid operation of the float arm 20 due to wave action. As shown in more detail in figure 7 and 9, a rim 51 projects from the cap 29 around the hole 27. The rim 51 has at least one opening 52(in the form of an aperture or a gap for example) for fluid to flow through. In the preferred form shown, the rim 51 comprises one or more arcuate protrusions/projections (51a, 51b and 51c in figures 7 and 9) extending from the cap 29 around the hole 27. Any number of protrusions/projection 51a/51b/51c can be employed provided they are separated such that at least one gap 52 is provided in the rim 51 for fluid to flow through. The end of each protrusion/projection 51a/51b/51c (or the end of the rim 51) projects past the level at which the hole 27 lies to enable contact with the seal 28 prior to closure of the hole 27.

As shown in figure 6 and in particular figure 7, when the float is bouncing in the water due to wave action, the rim 51 contacts the seal 28 and prevents the seal 28 from contacting and closing the hole 27. The seal 28 in this instance would sit on the rim 51(when fluid level has risen slightly due to wave action) but not compress enough to close hole 27. In other words, the wave does not provide sufficient force on the float arm 20 to pivot it enough to compress the seal 28 against the rim 51 to a level where it contacts against and closes the hole 27. In the case of the preferred embodiment, the seal 28 is shown resting on and slightly compressed against protrusions 51b and 51c, but is well clear of the hole 27. Fluid will therefore continue to flow through the hole 27 and through the opening(s) 52 in the rim 51to maintain an open valve 100.

As shown in figure 8 and in particular figure 9, when there is sufficient force to pivot the float arm 20 towards the closed position (due to rising fluid level in the reservoir) the float arm 20 compresses the seal 28 further against the rim 51 until the seal 28 contacts against the hole 27 to close the hole 27. This will in turn close the valve 100 as described above. The seal 28, preferably being made from a compressible material such as rubber material, therefore acts as a dampening member as well as a sealing member in the valve 100.

The foregoing description of the invention includes preferred forms thereof. Modifications may be made thereto without departing from the scope of the invention as defined by the accompanying claims.

Claims

CLAIMS:

1. A float valve comprising: a valve body having a hollow interior, an inlet port to connect a hydraulic or pneumatic system to the interior of the body of the valve, an outlet port for fluid flow from the interior of the body of the valve, a diaphragm movably mounted within the interior of the valve body and normally closing the inlet port,

an opening to communicate fluid pressure from the interior of the body of the valve on an inlet port side of the diaphragm, into a cavity on an opposite side of the diaphragm, such that when fluid pressure on said opposite side of the diaphragm falls below fluid pressure on the inlet side of the diaphragm, the diaphragm will move to open the interior of the valve to fluid flow through the valve from the inlet port to the outlet port, and will move to close the interior of the valve to fluid flow through the valve when fluid pressure on said opposite side of the diaphragm is equalised with fluid pressure on the inlet side of the diaphragm, a hole from the interior of the valve on said opposite side of the diaphragm, to an exterior of the valve, a float arm pivotally coupled at one end of the float arm to the valve body adjacent the hole and adapted at an opposite end of the float arm to be coupled to a float, a rim projecting about the hole from the interior of the valve on said opposite side of the

diaphragm to an exterior of the valve, and at least one rim opening through a side wall of the rim, and a compressible sealing member carried by said one end of the float arm to move with the float arm, which sealing member does not contact the rim in a position of the float arm which fully opens the valve, contacts the rim without closing the rim opening in an intermediate position of the float arm which also fully opens the valve, and is sufficiently compressible to contact and compress against the rim to close the rim opening in another position of the float arm which closes the valve.

2. A float valve as claimed in claim 1 wherein the rim comprises multiple rim openings through the side wall of the rim around the rim.

3. A float valve as claimed in either one of claim 1 or claim 2 comprising a guide pin extending through an opening in the diaphragm.