AU742512B2 - Ball valve - Google Patents

Description

PCT/AU99/00666 1 Received 24 November 2000 BALL VALVE The invention relates to a valve member for a valve of the ball valve type.

BACKGROUND OF THE INVENTION Ball valves manufactured form plastic material are known. These valves incorporate a rotatable plastic ball adapted to close off a thoroughbore. The ball has a central hole or aperture roughly equal to the thoroughbore of the valve. The ball is encapsulated between valve seats which comprise two ring seals mounted inside a valve body. The external surface of the ball has a part spherical shape around the area in contact with the seals. The spherical surface of the ball must not have any distortions and requires a high quality surface finish in order to achieve proper sealing.

In conventional plastic ball valves the ball is of a single configuration that is injection moulded. After moulding the ball needs to be machined, because due to its geometry it is impossible to obtain a spherical shape of the external surface in the injection moulding process. Frequently there is an additional operation required, to improve the surface finish of external surface of the ball.

Plastics used to produce the ball are often very expensive, because they must fulfil strict requirements of high wear resistance and low coefficient of friction.

As a result the process of producing a plastic ball valve ball is inefficient and costly.

The object of the invention is to provide a new and improved ball or valve member for a valve of the ball valve type, that has reduced manufacturing cost or at least provides the public with a useful alternative.

SUMMARY OF THE INVENTION In one form of the invention there is proposed a valve member for a valve of the ball valve type including: a frame having a flow passage and having two sets of attachment means on AMED;, SHEET 4RFi $EAU PCT/AU99/00666 2 Received 24 November 2000 opposing sides; at least two parts each having a set of lugs adapted to engage said frame attachment means in a snap-fit arrangement to form said valve member; the valve member having a sealing surface on at least one side spaced apart from said flow passage; and means on said valve member for engagement of a drive mechanism to enable rotation of the valve member in the valve.

In a preferred form said two parts are identical.

In a preferred form said valve member includes a pair of opposed sealing surfaces.

In a preferred form said two parts are hemispherical shells.

In a preferred form the frame further includes a tube portion to provide a smooth flow path.

In a preferred form said parts in the region of the sealing surfaces are comprised of constant thickness of material to provide smoothness of the sealing surfaces.

In a preferred form the at least two parts are adapted to encapsulate said frame.

In a preferred form the frame further includes a projection means on opposing sides of the frame for positive location of each said part.

In a preferred form said projection means are X type structures.

In a preferred form each part has a recess adapted to engage said projection means to assist in transfer of rotation forces from the frame to the parts.

In a preferred form the three component parts are manufactured by injection moulding.

N PIEA/DE AHEE PF..,Vg[ PCT/AU99/00666 Received 24 November 2000 In another form of the invention there is provided a valve assembly of the ball valve type including an inlet and an outlet including a valve member as described in any of the embodiments above, wherein a ball valve member is adapted to rotate between a first position and a second position in the valve assembly wherein in said first position a flow path through the valve member is substantially coaxial to a pipe and in the second position the flow path through the valve member is substantially transverse to the pipe.

An advantage of this invention is that a ball valve member is made from only three components parts two of which are identical. This makes the manufacture and assembly of the valve member relatively simple and inexpensive. Furthermore, each of the component parts can be replaced when damaged, instead of replacement of the whole unit as in the prior art devices.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 depicts a ball valve assembly of the Prior Art; Figures 2A-2D depict orthogonal views of the valve member of the present invention in assembled and disassembled views; Figures 3A and 3B are perspective views of the components of the valve member of the present invention, in assembled and disassembled views; and

~L~'~SHEETIE

WO 00/11381 PCT/AU99/00666 4 Figures 4A and 4B depict a second embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS Turning now to the drawings in detail there is shown in Figure 1 shows a ball valve assembly with a prior art ball. The ball valve assembly 10 has a handle 12 to rotate the ball 13 by means of slot, O rings 14, 15 and a ball seat 16. It shows the prior art ball 13 comprised of a single piece construction. The drawback of this apparatus is mostly one of cost. The ball itself is costly and time consuming to manufacture. It is moulded as a single configuration and after moulding requires machining to obtain the correct shape. Often further io finishing operation is required to improve the surface finish of the external surface of the ball.

These difficulties are overcome in the ball for a ball valve of the present invention, the best method known to the applicant shown in Figures 2A-2C and exploded view Figure 2D. Figure 2A shows an assembled form of the valve member 20 in side view, with preferably identical parts 22 and 23 joined together at 25 to form the valve member 20. The dotted line depicts sealing surfaces 36 upon which a valve seat of a valve assembly sits. These sealing surfaces are circular and one is formed on each of the two parts 22 and 23, see also Figure 2B.

Bore 24 provides a flow passage through the ball valve 20. Drive transfer mechanism 26 enables the handle of the valve assembly (shown in Figure 1) to engage the valve member for rotational movement. Inter-engaging locking means 28 are provided on at least two opposing sides of a frame 27 to engage the respective parts of the valve member in a snap fit arrangement.

Inter-engaging locking means 28 are also used to rotatably drive the ball.

Figure 2C shows in greater detail the inter-engaging locking means 28 which enables the two parts 22 and 23 of the ball valve to be snap fit. The handle (not shown) is then able to lock into position and engage drive mechanism 26 to rotate the valve member from an open to a closed position when positioned in a pipe (not shown). Once in the open position a flow passage is established with alignment of the bore 24 and the pipe thereby enabling fluid (such as water) to flow. In the closed position the flow passage is not WO 00/11381 PCT/AU99/00666 established as the sealing surfaces are rotated to align with the pipe and thereby shut off any passage of fluid.

Turning now to Figure 2D which shows the components of the valve member in detail. The two parts are preferably identical and spherical in shape forming two spherical shells 22 and 23. Since they are identical they can be manufactured from the one die simplifying the manufacturing and assembly process. The shells include sealing surfaces 36 as depicted in the earlier Figures, and are located on opposed sides of the valve member and seal against the valve seat assembly when in use. The frame 27 includes bore 24 which provides a flow passage from one side of the valve member to another side, and such that engagement of the drive mechanism with the handle enables rotation of the valve member to present a pair of sealing surfaces or alternatively flow surfaces to a fluid supply.

Encapsulation of the frame by the ball valve parts is shown in Figure 3A, whereby alignment of the two parts ensures establishment of a throughbore to allow for the passage of fluid when the valve member is used in conjunction with a ball valve. It is however to be understood that the frame does not need to be wholly encapsulated by the shells. At times it may be advantageous to have the shells engage said frame without having to encapsulate it.

Greater detail of the components is shown in Figure 3B, in which the frame 27 includes a set of flanges 40 provided on opposing sides of the frame, which include engagement means that function to receive corresponding parts of the shells including hook means 46 on the parts, to effect encapsulation of the frame 27 by the two spherical shells. Projection means 32 are located on opposing sides of the frame for positive location of the shell with respect to the frame and are shown as X type structures protruding from opposing faces of the frame. The projection means may however be of any configuration sufficient to achieve the necessary location and drive of the frame to the spherical shells.

Recess 31 on the shell 22, 23 engage with projections 32 on the frame 27 to enable transfer of rotational forces from the frame to the shells.

The spherical shells each have cutouts 44 and 45, said cutouts being semicircular in shape. The shells also include hook means 46 at the periphery of WO 00/11381 PCT/AU99/00666 6 at least two opposing cutouts 44 whereby the hook means engage with engagement means of the flange of the frame in a snap fit action.

In addition the frame includes a ridge 50 extending the full circumference of said edge, these ridges engage with corresponding grooves 52 in each of the two spherical shells, to thereby enhance and strengthen the joining of the components of the valve member. The frame is thereby able to be encapsulated by the snap fit action of the two spherical shells to form a valve member for a valve of the ball valve type.

All components of the valve member can be injection moulded to provide an economic alternative to the prior art.

Another embodiment of the invention is illustrated in Figures 4A and 4B.

These figures depict a configuration of the valve member wherein the ball is formed from shells 56 and 58 and the throughbore 60 in the frame is at approximately 90 degrees forming a corner valve. It may be noted that the valve seat of the ball valve assembly which engages the sealing surface 61 does not cover the join 54 of the two spherical shells, as the join 54 would prevent the seal between the valve seat and the valve member. The drive mechanism can engage into slot 62 in the ball assembly.

This ball valve assembly of the present invention can also be applied with a throughbore having more that two apertures.

Throughout this specification the purpose has been to illustrate the invention not to limit this.

Claims (12)

1. A valve member for a valve of the ball valve type including: a frame having a flow passage and having two sets of attachment means on opposing sides; at least two parts each having a set of lugs adapted to engage said frame attachment means in a snap-fit arrangement to form said valve member; the valve member having a sealing surface on at least one side spaced apart from said flow passage; and means on said valve member for engagement of a drive mechanism to enable rotation of the valve member in the valve.

2. A valve member as in claim 1 wherein said two parts are identical.

3. A valve member as in either one of claim 1 or claim 2 wherein said valve member includes a pair of opposed sealing surfaces.

4. A valve member as in any one of the above claims wherein said two parts are hemispherical shells.

A valve member as in any one of the above claims wherein the frame further includes a tube portion to provide a smooth flow path.

6. A valve member as in any one of the above claims wherein said parts in the region of the sealing surfaces are comprised of constant thickness of material to provide smoothness of the sealing surfaces.

7. A valve member as in any one of the above claims wherein the at least two parts are adapted to encapsulate said frame.

8. A valve member as in any one of the above claims wherein said frame further includes a projection means on opposing sides of the frame for positive location of each said part. i ""~~UE;Iij PCT/AU99/00666 Received 24 November 2000

9. A valve member as in claim 8 wherein said projection means are X type structures.

A valve member as in either one of claim 8 or claim 9 wherein each part has a recess adapted to engage said projection means to assist in transfer of rotation forces from the frame to the parts.

11. A valve member as in any one of the above claims where the three component parts are manufactured by injection moulding.

12. A valve assembly of the ball valve type including an inlet and an outlet including a valve member as described in any of the embodiments above, wherein a ball valve member is adapted to rotate between a first position and a second position in the valve assembly wherein in said first position a flow path through the valve member is substantially coaxial to a pipe and in the second position the flow path through the valve member is substantially transverse to the pipe. L)4MUJ