WO2001036850A1

WO2001036850A1 - Ball valve with non-return valve

Info

Publication number: WO2001036850A1
Application number: PCT/AU2000/001397
Authority: WO
Inventors: Adrian John Nixon; David Hair
Original assignee: Adrian John Nixon; David Hair
Priority date: 1999-11-17
Filing date: 2000-11-16
Publication date: 2001-05-25
Also published as: AUPQ411799A0

Abstract

A ball valve (10) is disclosed having a valve housing (11) with a valve chamber (17) therein, a substantially spherical main ball valve member (18) received within the valve chamber and having a transfer passage (19) therethrough adapted, by rotation of the main ball valve member, to be moved progressively into and out of alignment with an inlet (13) and an outlet (16) to and from the valve housing. The main ball valve member also has a chamber (27) therein and in which is received a non-return or reflux ball (29), whilst a valve seat (28) is provided upstream of the required direction of fluid flow. A non-return or reflux ball locating member (30) is provided downstream of the required direction of flow and past which fluid can flow. When fluid flow is in the required direction through the valve the non-return or reflux ball is forced under fluid pressure against the locating member to be restrained thereby and to allow fluid flow past both the non-return or reflux ball and through, or past, the locating member when said transfer passage is aligned, or partially aligned, with said inlet and outlet to and from said valve housing. When fluid flow is opposite to the required direction the non-return or reflux ball is forced away from the locating member and into engagement with the valve seat within the ball valve member to prevent fluid flow from downstream to upstream of the ball valve.

Description

BALL VALVE WITH NON-RETURN VALVE

Technical Field

This invention relates to a ball valve for fluid flow control, particularly for liquids but also the control of the flow of gases and other fluid based media, and more particularly a ball valve incorporating a non-return, reflux or check facility in addition to the normal fluid flow control from fully on to fully off, and intermediate flow control between fully on and fully off.

Background Art

A number of conventional valves are available to control fluid flow, amongst which are stop valves, also known as standard valves; gate valves; and ball valves in relation to which the present invention is specifically designed.

Stop or standard valves achieve fluid flow control by utilising a valve member as adapted to be moved to and away from the. valve seat surrounding a fluid transfer port. The valve member carries a sealing member or washer formed from neoprene, nylon, fibre based materials, plastics or leather. The valve member is moved toward and away from the valve seat by a valve spindle and a rotatable handle. Such valves allow for variable flow adjustment, but also non-return or reflux action should circumstances arise whereby fluid flow in the direction opposite to the normal flow direction eventuates and by causing the valve member, under reverse fluid pressure, to automatically return to a position against the valve seat and closing the fluid transfer port. Such ensures that fluid flow will only occur in one direction from the inlet to the outlet of the valve and not in the reverse direction.

Due to friction effects between the washer and valve seat, and also exposure of the washer to corrosive fluids, the washers need to be replaced as their sealing effectiveness diminishes, and although stop or standard valves are competitively priced, and as a consequence are used extensively, the requirement to replace the washers from time to time is disadvantageous. This is particularly so where access to the stop or standard valve is limited, for example, beneath a paved surface where the valve may be performing a fire service function to a particular property. Such involves shutting off the water supply branch system effecting supply to a number of other properties and which involves obtaining permits from the relevant authorities, breaking through the paved surface, performing the washer replacement and thereafter repairing the damaged paved surface, all of which significantly affects maintenance costs .

On the other hand, gate valves are designed to control fluid flow at a slow rate, and comprise a gate, usually formed from brass, and in turn connected to a handle operated spindle which moves the gate member progressively across the path of fluid flow through the valve. Sealing against fluid flow through the valve is achieved by moving the gate member into a position against brass mating surfaces formed in the body of the valve. When in the fully opened position the gate member offers no impedance to fluid flow as it is located in the body, and in addition the sealing surfaces of the gate member are protected by the valve body when the valve is not opened and closed regularly.

Furthermore, as the gate member is moved at a relatively slow rate to the off position, the fluid flow rate is impeded slowly thus avoiding fluid hammer associated with sudden stoppage to flow rate which generates a shock wave through the fluid as it attempts to dissipate the sudden rapid change of fluid velocity.

However, the disadvantages, apart from wear of the sealing surfaces when the valve is frequently opened and closed, are that the valve cannot have an inbuilt nonreturn or reflux function and where necessary a separate non-return or reflux valve has to be installed which adds to the size and cost of the valve installation and additional fluid flow sealing functions.

Ball valves on the other hand are simple and compact valves which allow for fully closed to fully opened fluid flow by a quarter turn of a valve handle whereby to rotate a ball valve member within a valve housing. The ball" valve member has a diametrically extending passage therethrough, to once again allow unimpeded flow of fluid through the valve. Such valves are formed with seals on the inlet and outlet sides of the interior of the housing and which seal against the ball valve member and remain stationary as the ball valve member is rotated. The seals are often lubricated or formed from materials which self- lubricating to allow little, if any, maintenance. In addition, low torque levels are necessary for valve operation as against the stop or standard valve where a valve washer has to be forced into sealing engagement with a seat. However, such conventional ball valves provide no non-return or reflux function when required, and once again a separate non-return or reflux valve is necessary with the inherent size and cost problems referred to previously.

Non-return, reflux, check or butterfly valves are designed to allow fluids to pass therethrough in one direction from the valve inlet to its outlet. Such valves may include a hinged flap, sometimes spring loaded, which allows the fluid to push past the flap when flowing in the required direction, but which, with reversed fluid flow, is pushed under fluid pressure against an associated valve seat thus closing a port through the valve seat. One other example involves the use of a flat disc-shaped member movable on a locating shaft, and which may be spring loaded if required. The disc-shaped member is moved, under fluid pressure, from a position closing a port through a valve seat when fluid flow is in the required direction, whilst if fluid attempts to flow in the opposite direction the reverse fluid pressure acts, spring assisted if necessary, to return the disc member to engage the valve seat and close the port therethrough.

The object of the present invention is to utilise the advantages of a ball valve but with an in built nonreturn or reflux valve which does not require non-return or reflux fluid flow control by way of a separate valve.

Disclosure of the Invention In accordance with the present invention there is provided a ball valve having a valve housing with a valve chamber therein, a substantially spherical main ball valve member received within said valve chamber and having a transfer passage therethrough adapted, by rotation of said main ball valve member, to be moved progressively into and out of alignment with an inlet and an outlet to and from said valve housing, wherein said main ball valve member also has a chamber therein and in which is received a nonreturn or reflux ball, whilst a valve seat is provided upstream of the required direction of fluid flow, and a non-return or reflux ball locating member is provided downstream of the required direction of flow and past which fluid can flow, whereby, when fluid flow is in the required direction through said valve the non-return or reflux ball is forced under fluid pressure against said locating member to be restrained thereby and to allow fluid flow past both the non-return or reflux ball and through, or past, said locating member when said transfer passage is aligned, or partially aligned, with said inlet and outlet to and from said valve housing, and whereby when fluid flow is opposite to the required direction the non-return or reflux ball is forced away from said locating member and into engagement with said valve seat within said ball valve member to prevent fluid flow from downstream to upstream of said ball valve .

Brief Description of the Drawings

One preferred embodiment of the invention will now be described with reference to the accompanying drawings, in which;

Figure 1 is a cross-sectional view through a first preferred embodiment of the invention, and being a ball~ valve with its non-return or reflux valve in the operating position allowing fluid flow through the valve in the required direction,

Figure 2 is a similar cross-sectional view to that of Figure 1, but with its non-return or reflux valve in the non-operating or reflux position preventing fluid flow back through the ball valve in the wrong direction,

Figure 3 is a cross-sectional view of part of a ball valve in accordance with a second preferred embodiment of the invention in its non-operating or reflux position,

Figure 4 is a cross-sectional view of the ball valve of Figure 3 in its operating position,

Figure 5 is a cross-sectional view taken along line 5-5 of Figure 4,

Figure 6 is a cross-sectional view of part of a ball valve in accordance with a third preferred embodiment of the invention in its non-operating or reflux position,

Figure 7 is a cross-sectional view of part of a ball valve in accordance with a fourth preferred embodiment of the invention in its non-operating or reflux position, and

Figure 8 is a cross-sectional view taken along line 8-8 of Figure 7.

Best Modes of Carrying Out the Invention

With reference to Figures 1 and 2 of the drawings, the ball valve of this first preferred embodiment of the invention, and generally indicated as 10, consists of a main valve body 11 formed from any suitable material and having an extension 12 at one end through which a valve inlet port 13 is provided, suitably internally threaded at 14 to allow connection to an associated fluid pipeline (not shown) . The other end of the valve body receives a ball valve member retaining nut 15 screw threaded into the valve body and through which a valve outlet port 16 is provided, and which is also suitably internally threaded to allow connection to an associated fluid pipeline (also not shown) . The main body 11 and the retaining nut 15 together define a valve chamber 17 within which is received a substantially spherical main ball valve member 18 formed from two halves 18a and 18b adapted to be joined together to form the substantially spherical ball valve member. Alternatively the ball valve member could be formed in one piece. Seals (not shown) are strategically positioned in the chamber 17 adjacent the inlet and outlet ports to provide seals between the valve body and the retaining nut and ball valve member combination.

The ball valve member has a diametrically extending fluid transfer passage 19 therethrough whereby, when the ball valve member is rotated through 90° by means of a spindle or shaft 20 connected to the ball valve member and carrying an operating handle 21 with connecting screw 22, the passage 19 is brought progressively into and out of alignment with the inlet and outlet ports to allow adjustable fluid flow through the ball valve. The shaft 20 is held in axial position by a retaining nut 23 threadably received in a shaft receiving port 24 and bearing against a circumferentially extending flange 25 on the shaft, with a sealing ring 26 interposed between the flange 25 and the port 24.

The transfer passage 19 through the ball valve member, also defines a substantially spherical chamber 27 between the ends of the passage, whereby to define at the fluid inlet side of the ball valve member a semi-spherical valve seat 28 forming part of a non-return or reflux valve against which a spherical non-return or reflux ball 29 can seat when fluid flow tends towards the undesirable reverse or reflux direction under fluid pressure coming from the direction of the outlet port to the inlet port, that is, from downstream to upstream (see Figure 2) .

However, with reference to Figure 1 of the drawings, when fluid flow (fluid pressure) is in the right direction, that is, when the transfer passage 19 through the ball valve member 18 is aligned, or partially aligned, with the inlet and outlet ports 13 and 16, and fluid pressure is directed from the inlet port to the outlet port, the non-return or reflux ball is urged under fluid pressure, toward a locating member 30 carried either by the main ball valve member 18 or its retaining nut 15, whereby fluid flow from the inlet port to the outlet port is achieved around the non-return or reflux ball and the locating member. In this embodiment a port 32 is provided through the locating member to allow fluid pressure in the non-return or reflux direction to be applied to the non- return or reflux ball whereby to urge it towards the valve seat 28 to stop reverse or reflux fluid flow through the valve.

Other advantages of using the non-return or reflux ball 29 is that it moves randomly around inside the chamber 27 within the main ball valve member, whereby the parts of the surface of the ball member which seat on the valve seat 28 will also be random thus reducing or spreading wear on any particular parts of the surface of the ball member 29.

In the second preferred embodiment of the invention, as shown in Figures 3, 4 and 5, the same reference numerals have been used for components which are the same as the embodiment of Figures 1 and 2. However, in this embodiment the movement of the spherical non-return or reflux ball 29 to engage the valve seat 28 is spring assisted by a compression coil spring 33, one end of which is received in a blind hole 34 formed in the locating member 30, whilst the other end of the spring bears against the non-return or reflux ball 29 to normally urge it against the valve seat 28 as shown in Figure 3. The exception is when fluid flow pressure in the right direction forces the ball 29 towards and/or against the locating member 30 whereby fluid flow through the ball valves occurs when the ball valve member 18 is rotated through, or partially through, 90° to align, or partially align, its transfer passage 19 with the inlet and outlet ports 13 and 16. In this second embodiment of the invention the port 32 through locating member 30 is omitted, but could still be included as a port smaller in diameter than the blind hole 34, and whereby to provide additional fluid pressure in the non-return or reflux direction. In this modification, the ledge formed at the transition between the blind hole 34, and the equivalent of the smaller diameter port 32, would provide a seat to locate the end of the compression coil spring 33.

In this second preferred embodiment, as can be the case in all other embodiments, radially inwardly extending ribs 35 may be provided, in this case four ribs equally spaced around the interior of the main ball valve member 18 and within the chamber 27 to guide the non-return or reflux ball 29 during its movement, but, if necessary, still allowing some degree of random movement of the ball member 29 to spread the share of wear on it as referred to previously.

The third preferred embodiment of Figure 6 of the drawings, where once again the same reference numerals of the embodiment of Figures 1 and 2 have been used for the same components, is substantially the same as the embodiment of Figures 3, 4 and 5, except that the compression coil spring 33 is replaced by a compression bellows type integer 36 of plastic material which performs similarly to the coil spring 33 of the preceding embodiment .

In the fourth, and final, embodiment of the invention, and as shown in Figures 7 and 8 of the drawings, and where once again the same reference numerals have been used for the same components as for the previous embodiments, the locating member 30 is replaced by a spring member 37 which performs the dual function of a locating member as well as a spring biasing means for normally biasing the ball member 29 toward and against the valve seat 28 in the non-return or reflux position. The spring member 37, which may be formed from spring steel or a resiliently flexible plastics material, has a circumferential retaining ring portion 37a captured within a circumferential groove 38 formed around the inside of the main ball member 18 adjacent the outlet port 16. The spring member 37 further has a plurality of tongues 37b, in this case three circumferentially and equally spaced tongues which extend radially inwardly and then axially of the transfer passage 19, or chamber 27, whilst their free ends act to bear against and bias the ball member toward the valve seat 28 as with the previously described preferred embodiments which utilise biasing means for the ball member (Figures 3 to 5, and Figure 6, of the drawings) . The spaces 39 between the tongues 37b allow for the passage of fluid under pressure in either the normal flow or reflux flow directions.

The non-return or reflux ball member 29 may be made from any suitable material, such as rubber, or a plastics material, or even a metallic material, as can any other component of the ball valve, but within prevailing manufacturing, technical and other requirements as set by the relevant regulatory authority. The main ball valve member may be formed as a single member as distinct from two halves, but in such a case a port therethrough with an appropriate closure member should be provided so that the non-return or reflux ball member 29 can be inserted during manufacture, or old ball members removed and new ball members inserted as replacements when required during maintenance of the ball valve

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A ball valve having a valve housing with a valve chamber therein, a substantially spherical main ball valve member received within said valve chamber and having a transfer passage therethrough adapted, by rotation of said main ball valve member, to be moved progressively into and out of alignment with an inlet and an outlet to and from said valve housing, wherein said main ball valve member also has a chamber therein and in which is received a non-return or reflux ball, whilst a valve seat is provided upstream of the required direction of fluid flow, and a non- return or reflux ball locating member is provided downstream of the required direction of flow and past which fluid can flow, whereby, when fluid flow is in the required direction through said valve the non-return or reflux ball is forced under fluid pressure against said locating member to be restrained thereby and to allow fluid flow past both the non-return or reflux ball and through, or past, said locating member when said transfer passage is aligned, or partially aligned, with said inlet and outlet to and from said valve housing, and whereby when fluid flow is opposite to the required direction the nonreturn or reflux ball is forced away from said locating member and into engagement with said valve seat within said ball valve member to prevent fluid flow from downstream to upstream of said ball valve.

2. A ball valve as claimed in Claim 1, wherein the pressure of said fluid forces the non-return or reflux ball away from said locating member and into engagement with said valve seat .

3. A ball valve as claimed in Claim 1, wherein a biasing means is provided to force the non-return or reflux ball away from said locating member and into engagement with said valve seat .

4. A ball valve as claimed in Claim 1, wherein a biasing means is provided and a combination of said biasing means and the pressure of said fluid forces the non-return or reflux ball away from said locating member and into engagement with valve seat .

5. A ball valve as claimed in Claim 3 or 4, wherein said biasing means provides the dual functions of biasing means and said locating member.

6. A ball valve as claimed in Claim 5, wherein said biasing means includes a circumferential retaining ring portion captured in a circumferential groove formed around the inside of the main ball valve member adjacent said outlet, and further includes a plurality of tongues extending radially inwardly and then axially of said transfer passage with the free ends bearing against and biasing the non-return or reflux ball toward the valve seat .

7. A ball valve as claimed in any one of the preceding claims, wherein the main ball valve member is formed from two parts which are adapted to be joined together.

8. A ball valve as claimed in any one of Claims 1 to 6, wherein the main ball valve member is formed as a single part.

9. A ball valve as claimed in any one of the preceding claims, wherein said chamber of said main ball valve member has a plurality of ribs formed therein and extending in the direction of fluid flow to assist in guiding the non-return or reflux ball during its movements.

10. A ball valve substantially as hereinbefore described with reference to Figures 1 and 2, or 3 to 5, or 6 or 7, of the accompanying drawings.

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