AU2013205018A1 - Fluid flow control valve member and fluid flow control valve - Google Patents

Abstract

FLUID FLOW CONTROL VALVE MEMBER AND FLUID FLOW CONTROL VALVE A first aspect the invention concerns a fluid flow control valve member (12) for use with a valve body (14) adapted for installation in a valve port of a tap having a tap spindle (26). The fluid flow control valve member includes a piston (16) having a first side (18) and an opposite second sealing side (20). A stem (22) extends outwardly from the first side of the piston for operative engagement with the tap spindle. The piston includes a lip (96) extending transversely outwardly from the piston, the lip being adapted to abut a stop surface of the valve body during movement of the piston towards the valve body to limit movement of the piston towards the valve body upon the abutment of the lip with the stop surface. 3b

Description

1 FLUID FLOW CONTROL VALVE MEMBER AND FLUID FLOW CONTROL VALVE FIELD [0001] The present invention relates to a fluid flow control valve member and a fluid flow control valve. [0002] The present invention has been developed for use as a mains water tap valve and will be described hereinafter with reference to that application. It will, however, be appreciated that the invention may also be used in non-mains fluid systems. BACKGROUND [0003] A conventional mains water tap typically comprises a metal tap body having a water inlet, for connection to a water reticulation system, a water outlet and a passage extending between the water inlet and outlet. An annular valve port, surrounded by an annular valve seat, is provided in the passage between the water inlet and outlet. A fluid flow control valve member is axially movable within the passage into and out of sealing engagement with the valve seat to respectively open and close the tap. [0004] The valve member is typically provided in the form of a jumper valve comprising a rubber washer carried on a circular piston and a stem projecting outwardly from the piston. The stem is slidingly receivable within a recess, the so-called stem well, formed in an inner end of a spindle in the tap body, the tap spindle being axially movable within the tap body between a closed position and an open position. In the closed position, the tap spindle urges the valve member into sealing engagement with the valve seat. In the open position the valve member is free floating between the valve seat and the tap spindle so as to move out of engagement with the valve seat in response to water pressure and thereby to allow water to pass from the inlet through the passage so as to be dispensed at the outlet. [0005] Disadvantages associated with existing water taps include that the valve member washer is often damaged due to over-tightening or that excessive force of the tap spindle causes the jumper valve to crack or otherwise be destroyed. Also, repeated reseating of a tap seat results in 2 a valve port with limited thickness. That reduced thickness can cause the seal located in the valve port to sit loose and not seal adequately causing leakage. Another disadvantage is that when valve member washers are over-tightened, damage is caused to tap seats and valve bodies resulting in a reduced lifecycle of taps and valve bodies. [0006] The top assemblies of taps are often replaced leaving the original tap body behind. The effect of this is that the products of different manufactures, and of varying quality, are combined in a single tap. Many top assemblies are, however, characterised by tap spindles that are of poor quality due to large tolerances or low quality control or simply do not properly match the tap body to which they have been fitted, thus resulting in leakage. In addition, the spindle wells of recently manufactured tap spindles tend to have larger bore diameters than those of older tap spindles, which permits significant side-to-side movement of a jumper stem within the spindle well. A combination of the above factors typically results in the jumper valve engaging the tap seat unevenly causing rapid wear in the jumper valve. OBJECT [0007] It is the object of the present invention to substantially overcome or at least ameliorate one or more of the above disadvantages, or to provide a useful alternative. SUMMARY [0008] According to a first aspect of the invention there is disclosed herein a fluid flow control valve member for use with a valve body adapted for installation in a valve port of a tap having a tap spindle; the fluid flow control valve member including: a piston having a first side and an opposite second sealing side; and a stem extending outwardly from the first side of the piston for operative engagement with the tap spindle, wherein the piston includes a lip extending transversely outwardly from the piston, the lip being adapted to abut a stop surface of the valve body during movement of the piston towards the valve body to limit movement of the piston towards the valve body upon the abutment of the lip with the stop surface. [0009] Preferably the piston on its first side includes a pressure distribution body adapted to distribute downward pressure of the tap spindle across the first side of the piston.

3 [0010] Preferably the fluid flow control valve member includes a circumferential flange axially extending from the second sealing side of the piston and operatively adapted to engage a valve seat of the valve body. [0011] Preferably the flange includes chamfered edges for operative engagement with the valve body. [0012] Preferably the piston on its second sealing side includes an inclined stop surface operatively associated with a corresponding inclined surface of a stop protrusion of the valve body, in use movement of the piston towards the valve body is limited upon abutment of the stop surface with the inclined surface of the stop protrusion. [0013] Preferably the fluid flow control valve member includes a guide stem longitudinally extending from the sealing side of the piston, in use the guide stem being adapted to guide the piston into sealing alignment with the valve body. [0014] Preferably the guide stem tapers longitudinally towards a curved end. [0015] According to a second aspect of the invention there is disclosed herein a fluid flow control valve for installation in a valve port of a tap having a tap spindle; the fluid flow control valve including: a valve body comprising a spigot extending outwardly from the valve body between an outlet end defining an outlet port and an inlet end defining an inlet port, the spigot being adapted to be operatively received within the valve port; a piston having a first side and an opposite second sealing side; and a stem extending outwardly from the first side of the piston for engagement with the tap spindle, wherein the piston includes a lip extending transversely outwardly from the piston, the lip being adapted to abut a stop surface of the valve body during movement of the piston towards the valve body to limit movement of the piston towards the valve body upon the abutment of the lip with the stop surface. [0016] Preferably the spigot includes a first seal and a second seal adapted to sealingly engage inner surfaces of the valve port.

4 [0017] Preferably the first seal and the second seal are O-rings. [0018] Preferably the spigot includes a seal having an axial thickness of between 3.6 and 3.8mm. [0019] Preferably the inlet end includes a chamfered outer edge. [0020] Preferably the inlet end includes a chamfered inner edge. [0021] Preferably the valve body includes a perimeter body surrounding the spigot. [0022] Preferably an inner surface of the perimeter body and an outer surface of the spigot define a groove adapted to hold a valve body seal. [0023] Preferably the valve body seal is an O-ring. [0024] According to a third aspect of the invention there is disclosed herein a fluid flow control valve member for use with a valve body adapted for installation in a valve port of a tap having a tap spindle, the fluid flow control valve member including: a piston having a first side and an opposite second sealing side, a stem that extends outwardly from the first side of the piston for operative engagement with the tap spindle, and a guide stem which extends longitudinally outwardly from the sealing side of the piston and is operatively adapted to guide the piston into sealing alignment with the valve body during movement of the piston towards the valve body. [0025] According to a fourth aspect of the invention there is disclosed herein a fluid flow control valve for installation in a valve port of a tap having a tap spindle, the fluid flow control valve including: a valve body having a spigot extending outwardly from the valve body between an outlet end having an outlet port and an inlet end having an inlet port, the spigot being adapted to be operatively received within the valve port; and a fluid flow control valve member operatively associated with the valve body, the fluid flow control valve member including: a piston having a first side and an opposite second sealing side; and 5 a stem which extends outwardly from the first side of the piston for operative engagement with the tap spindle, wherein the spigot supports a first seal and a second seal operatively adapted to sealingly engage inner surfaces of the valve port. [0026] According to a fifth aspect of the invention there is disclosed herein a fluid flow control valve member for use with a valve body adapted for installation in a valve port of a tap having a tap spindle, the fluid flow control valve member including: a piston having a first side and an opposite second sealing side; a stem extending outwardly from the first side of the piston for operative engagement with the tap spindle, and a circumferential flange axially extending from the second sealing side of the piston and adapted for engagement with a valve seat of the valve body, the flange including chamfered edges for operative abutment with the valve seat. [0027] According to a sixth aspect there is disclosed herein a tap having a fluid flow control valve member according to the first, third or fifth aspects. [0028] According to a seventh aspect there is disclosed herein a tap having a fluid flow control valve according to the second or fourth aspects. [0029] According to an eighth aspect of the invention there is disclosed herein a fluid flow control valve for installation in a valve port of a tap having a tap spindle, the fluid flow control valve including: a valve body including (i) a spigot extending longitudinally outwardly from the valve body between an outlet end having an outlet port and an inlet end having an inlet port, the spigot being adapted to be operatively received within the valve port, and (ii) a perimeter body surrounding the spigot; a fluid flow control valve member operatively associated with the valve body, the fluid flow control valve member including (i) a piston having a first side and an opposite second sealing side, and (ii) a stem which extends outwardly from the first side of the piston for operative engagement with the tap spindle, wherein the spigot and the perimeter body define a groove operatively adapted to hold a valve body seal, the perimeter body including a stop protrusion and a support lip which extend 6 into the groove and are operatively adapted to limit deformation of the valve body seal when the tap spindle causes the fluid control valve member to be moved towards the valve body. BRIEF DESCRIPTION OF THE DRAWINGS [0030] Preferred embodiments of the invention will be described hereinafter, by way of examples only, with reference to the accompany drawings, in which: [0031] Figure 1 is a cross-sectional side view of a fluid flow control valve in accordance with a first embodiment of the present invention; [0032] Figure 2 is a cross-sectional side view of a household tap incorporating the fluid flow control valve of Figure 1; [0033] Figure 3 is a cross-sectional side view of the household tap of Figure 2, with a reduced valve port, incorporating the fluid flow control valve of Figure 1; [0034] Figure 4 is a cross-sectional side view of the fluid flow control valve of Figure 1 in an open position; [0035] Figure 5 is a cross-sectional side view of the fluid flow control valve of Figure 1 in a closed position; [0036] Figure 6 is a cross-sectional side view of a fluid flow control valve in accordance with a second embodiment of the present invention; [0037] Figure 7 is a cross-sectional side view of a household tap incorporating the fluid flow control valve of Figure 6; [0038] Figure 8 is a cross-sectional side of the household tap of Figure 7, with a reduced valve port, incorporating the fluid flow control valve of Figure 6; [0039] Figure 9 is a cross-sectional side view of a fluid flow control valve in accordance with a third embodiment of the present invention; 7 [0040] Figure 10 is a cross-sectional side view of a household tap incorporating the fluid flow control valve of Figure 9, the fluid flow control valve member of the fluid flow control valve being located in a first position; and [0041] Figure 11 is a cross-sectional side view of the household tap of Figure 10, wherein the fluid flow control valve member is located in a second position. DESCRIPTION OF PREFERRED EMBODIMENTS [0042] In the specification like reference numerals will be used to indicate like components. [0043] Figure 1 shows a first embodiment fluid flow control valve generally indicated with the reference numeral 10. The fluid flow control valve 10 comprises a fluid flow control valve member 12 and a valve body 14. [0044] The fluid flow control valve member 12 comprises a piston 16 having a first side 18 and an opposite second sealing side 20. A stem 22 extends generally perpendicularly outwardly from the first side 18 of the piston 16. In use the stem 22 is received within a recess 24, hereinafter referred to as the spindle well, defined in an operative lower end of a tap spindle 26 (illustrated in Figure 2). [0045] The piston 16 is at least partially received within an annular passage 28 defined by an inner wall surface 30 of the valve body 14. The valve body 14 is generally cylindrical and has an outer diameter which is only marginally larger than the outer diameter of the piston 16 of the valve member 12. The fluid flow control valve 10 comprises a spigot 48 that longitudinally extends along a central axis 36 between outlet end 34 having an outlet port 70, and an inlet end 32, having an inlet port 84. A valve seat 38 is defined proximate the outlet port 34. [0046] The valve member 12 is axially reciprocably moveable along the axis 36 within the valve body 14 to be located in an open position, illustrated in Figure 4, in which the valve member 12 is disengaged from the valve seat 38, and a closed position, illustrated in Figure 5, in which the valve member 12 sealingly engages the valve seat and 38. [0047] The valve seat 38 comprises a sealing member 40, here in the form of an 0-ring referred to as the body 0-ring, which is engageable by a circumferential circular flange 42 extending 8 axially from the piston 16 of the valve member 12. The body O-ring 40 is retained within a groove 44 defined by an inner surface 30 of a cylindrical perimeter body 31 of the valve body 14 and an outer surface 46 of a spigot 48 that extends axially outwardly from the valve body 14. The body O-ring 40 defines a first upper sealing surface 50 engageable by the circular flange 42 of the valve member 12 and a second lower sealing surface 52 that is in use located proximate a valve seat 54 of a valve port 56 of a mains water tap 58, shown in Figure 2 and Figure 3. [0048] The spigot 48 includes a grooved portion 60 adapted to be operatively received within the valve port 56. The spigot 48 includes within the grooved portion sealing means 62, here in the form of an upper and a lower O-ring 64 and 66, which extend around the periphery of the spigot 48. The top edge 61 of the lower O-ring 64 is spaced between 0.65 and 0.75mm from the bottom edge of the upper O-ring 66. In use the O-rings 64 and 66 will sealingly engage the valve port 56 and maintain the spigot within the valve port 56 as discussed below. [0049] Figure 2 illustrates the fluid flow control valve 10 in use and inserted into the mains water tap 58 such that the spigot 48 is located within the valve port 56 and held in position by the O-rings 64 and 66. The stem 22 of the valve member 12 is located within the spindle well 24 so as to be engaged with the tap spindle 26 in the conventional manner. By engaging a handle 68, a user can screw the tap spindle 26 downwardly to move axially towards the valve seat 38, thereby urging the valve member 12 towards the closed position illustrated in Figure 4. In the closed position, the second sealing side 20 of the piston 16 is sealingly engaged with the outlet port 70 of the spigot 48. Turning the handle 68 in the opposite direction screws the tap spindle 26 upwardly away from the valve seat 38 and disengages the piston 16 of the valve member 10 from the valve seat 38, thereby opening the outlet port 70. With the valve 10 open, mains water pressure on the second sealing side 20 of the piston 16 will urge the valve member 12 towards the tap spindle 26, so as to locate at least a portion of the stem 22 within the spindle well 24. [0050] As shown in Figure 2, the upper O-ring 64 engages the internal portion of the valve port 56 with the lower O-ring 66 engaging a bottom portion of the valve port 56. The valve seat 54 in Figure 2 has not been subjected to any reseating operation. The applicant estimates that about 10% of all mains water taps have a reduced valve seat due to repeated reseating operations. This is the result of a common practice in the plumbing industry to reseat the valve seat each time a tap washer is to be replaced.

9 [0051] Figure 3 illustrates a mains water tap 58 of which the valve seat has been subjected to a number of reseating operations. In this case the valve port has been reduced to a thickness of less than 4mm. The result of this is that the lower O-ring 64 is no longer in sealing engagement with the valve port 56. However, due to the presence of the upper O-ring 66, the sealing means 62 is able still to provide sealing due to the presence of the upper O-ring 64 within the valve port 56. This is contrary to conventional control valves which employ a single O-ring on the spigot of the valve body. In the case of damage to that single seal the valve will be prone to leakage. Also, where the valve seat has been subjected to a number of reseating operations, the single seal will tend to sit loose within the valve port and not seal. [0052] Figure 6 shows a second embodiment fluid flow control valve 110. The control valve 110 also comprises a fluid flow control valve member 12 and a valve body 14. The control valve 110 differs from the control valve 10 in that the upper and lower O-rings 64 and 66 have been replaced with a single seal 112 having a thickness which is elongated in the axial direction. The seal 112 has a thickness of between 3.6 and 3.8mm. [0053] Figure 7 shows the control valve 110 employed in a mains water tap 58. The valve seat 54 has not been subjected to any reseating operation and the entire axial width of the seal 112 is held within the valve port 56. Figure 8 shows a mains water tap 58 of which the valve seat 54 has been subjected to a number of reseating operations so that the valve port 56 has been reduced to a thickness of less than 4mm. However, as a result of the dimensions of the seal 112, although a lower portion thereof is no longer contained within the valve port 56, an upper portion of the seal maintains sealing contact with the interior of the valve port 56. [0054] Returning to Figure 1, the control valve 10 includes a pressure distribution body 80, here in the form of a nylon disc. The pressure distribution body 80 is mounted about the stem 22 and is located above the first side 18 of the piston 16. In use the pressure distribution body 80 will distribute downward force from a tap spindle across a broader area of the piston 16 so as to deter damage to the tap spindle or control valve 10. The pressure distribution body 80 is produced from a material which displays an amount of resiliency so as to curb the unwanted effects of damaged or poorly manufactured tap spindles that do not properly align with the valve member 12. It will be understood that a range of materials could be employed to produce the pressure distribution body, for example different types of plastics or ceramic.

10 [0055] To deter damage to the body O-ring 40 the lower O-ring engaging edges 82 of the circular flange 42 have been chamfered, here to RO.40. Chamfering of the O-ring engaging edges 82 will deter them grinding into and damaging the body O-ring 40. [0056] It has been known that water travelling through the inlet port of a control valve spigot may cause whistling, shuddering and buffeting in a tap. To deter such occurrence the inlet end 32 has a chamfered inner edge 86. Typically the chamfer will be between 14 and 45'. Such chamfering will provide a rounded part for water facilitating smooth flow to deter any whistling or shuddering. [0057] The spigot 48 at the inlet end 32 includes a lower edge 88 which defines the inlet port 84. The lower edge 88 includes an outer surface 90 chamfered to about 45'. Having that chamfered outer surface 90 will deter the O-rings 64 and 66 being damaged by that surface while being rolled onto the spigot 48 during manufacturing assembly. [0058] The second sealing side 20 of the piston 16 includes a substantially planar outlet engaging face 71, shown in Figure 4, contrary to known pistons having a scalloped bottom surface. Such a planar face addresses pipe shuddering and vibrations associated with scalloped valve members. Furthermore, the planar outlet engaging face 71 facilitates proper alignment and abutment with a substantially planar piston engaging face 73, also shown in Figure 4. This arrangement will serve to deter deformation of the piston 16 and damage to the body O-ring 40. [0059] The perimeter body 31 extends longitudinally between a valve seat end 91 and a valve member end 92. In use the valve seat end 91 will be located adjacent the valve seat 54 of the mains water tap 58 with the spigot 48 passing through the valve port 56 (as illustrated in Figure 2). At the valve member end 92 the perimeter body 31 defines an annular stop surface 94. The piston 16 in turn includes a radially outwardly extending stop lip 96 that is operatively associated with the stop surface 96. In use continued downward movement of the tap spindle 26, and as a result downward movement of the valve member 12, will be limited by the stop lip 96 abutting the stop surface 94 of the perimeter body 31. This will deter the circumferential flange 42 digging into the body O-ring 40 which could cause damage. [0060] The piston 16 further includes a lower inclined stop surface 98 that is operatively associated with a corresponding inclined surface 99 of a stop protrusion 100 that extends 11 radially from the perimeter body 31 into the annular passage 28. Downward movement of the piston 16 will be limited when the stop surface 98 abuts the stop protrusion 100. [0061] The body O-ring 40 is a BS205 O-ring. The body O-ring 40 is at its lower end supported by a support lip 102 that extends radially into the annular passage 28. The support lip 102 includes a bottom surface having a length of 0.80mm. The support lip 102 is configured to as to deter the lower sealing surface protruding beyond the valve seat end 90, thereby to deter damage being inflicted to the body O-ring by imperfections, such as an uneven surface, of the valve seat 54. [0062] To deter uncontrolled deformation of the body O-ring 48 or it protruding from a side of the valve body 14, the stop protrusion 100 and the support lip 102 are adapted to hold the body O-ring 48 in position in the groove 44 between the perimeter body 31 and the spigot 48. This arrangement seeks to deter the perimeter body 31 and the spigot 48 moving in different directions. [0063] In use abutment of (i) the second sealing side 18 of the piston 16 with the outlet port 70, (ii) the stop surface 94 with the stop lip 96 and (iii) the inclined stop surface 98 with the stop protrusion 100 combined with the dimensions of the body O-ring 40 all work together to deter damaged being inflicted by the valve member 12 to the body O-ring 40 when the tap spindle 26 is too tightly closed. [0064] Figure 3 shows a third embodiment fluid flow control valve, generally indicated with the reference numeral 120. The fluid flow control valve 120 is similar in construction to the fluid flow control valve 10 except for the fact that the fluid flow control valve 120 includes a guide stem 122 that tapers longitudinally outwards from the second sealing side 20 of the piston 16 towards a cured end 124. The purpose of the guide stem 122 is discussed with reference to Figures 10 and 11 where the control valve 122 has been incorporated in a mains water tap 58. The spindle well 24 here has such dimensions that it permits side-to-side movement of the stem 22. By providing the guide stem 122, downward movement of the tap spindle 26 will cause the guide stem 122 to move downwards. Such downward movement will move the guide stem 122 towards the outlet port 70. Due to the tapered shape of the guide stem 122, continued downward movement will cause the guide stem 122 to move down the outlet port 70 into the spigot 48. As the guide stem 122 is moved further down the spigot 48 it will cause the central 12 axis of the stem 36 to become aligned co-axially with the valve body 14 so as to ensure that the piston sealingly engages the valve body 141. The guide stem 122 address the problem often encountered with valve members which are ill aligned with the valve body as a result of sideways movement of a stem within an oversized spindle well. [0065] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims (24)

1. A fluid flow control valve member for use with a valve body adapted for installation in a valve port of a tap having a tap spindle, the fluid flow control valve member including: a piston having a first side and an opposite second sealing side; and a stem extending outwardly from the first side of the piston for operative engagement with the tap spindle, wherein the piston includes a lip extending transversely outwardly from the piston, the lip being adapted to abut a stop surface of the valve body during movement of the piston towards the valve body to limit movement of the piston towards the valve body upon the abutment of the lip with the stop surface.

2. A fluid flow control valve member according to claim 1, wherein the piston on its first side includes a pressure distribution body adapted to distribute downward pressure of the tap spindle across the first side of the piston.

3. A fluid flow control valve member according to either claim 1 or claim 2, including a circumferential flange axially extending from the second sealing side of the piston and operatively adapted to engage a valve seat of the valve body.

4. A fluid flow control valve member according to claim 3, wherein the flange includes chamfered edges for operative abutment with the valve seat.

5. A fluid flow control valve member according to any one of the preceding claims, wherein the piston on its second sealing side includes an inclined stop surface operatively associated with a corresponding inclined surface of a stop protrusion of the valve body, movement of the piston towards the valve body being limited upon abutment of the stop surface with the inclined surface of the stop protrusion.

6. A fluid flow control valve member according to any one of the preceding claims including a guide stem longitudinally extending from the sealing side of the piston, the guide stem being operatively adapted to guide the piston into sealing alignment with the valve body.

7. A fluid flow control valve member according to claim 6, wherein the guide stem tapers longitudinally towards a curved end. 14

8. A fluid flow control valve for installation in a valve port of a tap having a tap spindle, the fluid flow control valve including: a valve body having a spigot extending outwardly from the valve body between an outlet end having an outlet port and an inlet end having an inlet port, the spigot being adapted to be operatively received within the valve port; and a fluid flow control member operatively associated with the valve body, the fluid flow control valve member including: a piston having a first side and an opposite second sealing side; and a stem extending outwardly from the first side of the piston for operative engagement with the tap spindle, wherein the piston further includes a lip that extends transversely outwardly from the piston, the lip being operatively adapted to abut a stop surface of the valve body during movement of the piston towards the valve body to limit movement of the piston towards the valve body upon abutment of the lip with the stop surface.

9. A fluid flow control valve according to claim 8, wherein the spigot includes a first seal and a second seal operatively adapted to sealingly engage inner surfaces of the valve port.

10. A fluid flow control valve according to claim 9, wherein the first seal and the second seal are O-rings.

11. A fluid flow control valve according to claim 8, wherein the spigot includes a seal having an axial thickness of between 3.6 to 3.8mm.

12. A fluid flow control valve according to any one of claims 8 to 11, wherein the inlet end includes a chamfered outer edge.

13. A fluid flow control valve according to any one of claims 8 to 12, wherein the inlet end includes a chamfered inner edge.

14. A fluid flow control valve according to any one of claims 8 to 13, wherein the valve body includes a perimeter body surrounding the spigot. 15

15. A fluid flow control valve according to claim 14, wherein an inner surface of the perimeter body and an outer surface of the spigot defines a groove adapted to hold a valve body seal.

16. A fluid flow control valve according to claim 14, wherein the valve body seal is an 0 ring.

17. A tap having a fluid flow control valve according to claim 15, wherein the perimeter body longitudinally extends between a valve member end and a valve seat end, the valve seat operatively located adjacent a valve seat of the valve port of the tap, the perimeter body including an inwardly extending support lip that is operatively adapted to deter a bottom portion of the valve body seal protruding beyond the valve seat end when the body seal is caused to be deformed by downward movement of the piston.

18. A fluid flow control valve member for use with a valve body adapted for installation in a valve port of a tap having a tap spindle, the fluid flow control valve member including: a piston having a first side and an opposite second sealing side, a stem that extends outwardly from the first side of the piston for operative engagement with the tap spindle, and a guide stem which extends longitudinally outwardly from the sealing side of the piston and is operatively adapted to guide the piston into sealing alignment with the valve body during movement of the piston towards the valve body.

19. A fluid flow control valve for installation in a valve port of a tap having a tap spindle, the fluid flow control valve including: a valve body having a spigot extending outwardly from the valve body between an outlet end having an outlet port and an inlet end having an inlet port, the spigot being adapted to be operatively received within the valve port; and a fluid flow control valve member operatively associated with the valve body, the fluid flow control valve member including: a piston having a first side and an opposite second sealing side; and a stem which extends outwardly from the first side of the piston for operative engagement with the tap spindle, 16 wherein the spigot supports a first seal and a second seal operatively adapted to sealingly engage inner surfaces of the valve port.

20. A fluid flow control valve member for use with a valve body adapted for installation in a valve port of a tap having a tap spindle, the fluid flow control valve member including: a piston having a first side and an opposite second sealing side; a stem extending outwardly from the first side of the piston for operative engagement with the tap spindle, and a circumferential flange axially extending from the second sealing side of the piston and adapted for engagement with a valve seat of the valve body, the flange including chamfered edges for operative abutment with the valve seat.

21. A tap having a fluid flow control valve member according to any one of claims 1 to 7, 18 or 20 claims.

22. A tap having a fluid flow control valve according to any one of claims 8 to 17 or claim 19.

23. A fluid flow control valve for installation in a valve port of a tap having a tap spindle, the fluid flow control valve including: a valve body including (i) a spigot extending longitudinally outwardly from the valve body between an outlet end having an outlet port and an inlet end having an inlet port, the spigot being adapted to be operatively received within the valve port, and (ii) a perimeter body surrounding the spigot; a fluid flow control valve member operatively associated with the valve body, the fluid flow control valve member including (i) a piston having a first side and an opposite second sealing side, and (ii) a stem which extends outwardly from the first side of the piston for operative engagement with the tap spindle, wherein the spigot and the perimeter body define a groove operatively adapted to hold a valve body seal, the perimeter body including a stop protrusion and a support lip which both extend into the groove and are operatively adapted to limit deformation of the valve body seal when the tap spindle is caused to move the fluid control valve member towards the valve body. 17

24. A fluid flow control valve according to any one of claims 8, 19 or 23, wherein the outlet end defines a substantially planar piston engaging face operatively adapted to abut a substantially planar outlet engaging face of the piston. Combobulator Pty Ltd Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON