AU782288B2 - Valve - Google Patents

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

TO BE COMPLETED BY APPLICANT Name of Applicant: Actual Inventor: Address for Service: Invention Title: Miladin Ivanovic Miladin Ivanovic A.P.T. Patent and Trade Mark Attorneys PO Box 222, Mitcham, SA 5062 Valve Details of Associated Provisional Application No. PR4471 dated 18 April 2001 The following statement is a full description of this invention, including the best method of performing it known to me:- 02/06/2005 14:15 +61-8-82723255

APT

PAGE 26/45 2 FIELD OF THE INVENTION This invention relates generally to a fluid flow valve for a tap fitting or the like, and to a fluid flow valve for retro-fitting to an existing tap fitting or the like.

BACKGROUND OF THE INVENTION Fluid flow valves of the kind described herein are used in many applications where control of passage of a fluid is required. For example, the valves may be used in taps or stopcocks in industrial, commercial or domestic settings for the control of water, or other fluids.

The present invention is related to fluid flow valves of the type that have a spindle and piston moveable within the bore of a valve body. Generally speaking, the piston is connected to a sealing means and the piston and sealing means together are moveable axially within the valve body between a closed position wherein the sealing means is seated onto a valve seat to form a fluid tight seal and prevent fluid flow, and an open position where the sealing means is removed from the valve seat and fluid is able to flow. The piston may be threaded onto an end of the spindle with the spindle prevented from axial movement with respect to the valve body. Rotation of the spindle then causes the piston to move axially between the 20 open and closed positions. In one known example of a fluid flow valve of this type an outer surface of the piston is hexagonal in shape and the piston is moveable axially within a complementary hexagonal shaped inner bore of the valve body. Thus the piston is prevented from rotation with respect to the valve body and rotation of the spindle is translated into axial movement of the piston.

A problem with fluid flow valves described as well as with other types of fluid flow valves is that the sealing means and/or valve seat can wear over time and this can lead to an incomplete shut off of fluid flow. This is sometimes overcome by tightening the spindle further which forces the sealing means onto the valve seat 30 with greater force which can lead to an overtightening and jamming of the valve.

Similarly fluid flow valves may be overtightened in the open position and this too can lead to a jamming of the valve.

The prior art contains attempts to overcome at least some of these problems. For example, US 5,690,313 to Pesovic et. al. discloses a fluid flow valve that contains a slip clutch which prevents the valve from overtightening in the closed or open COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02 02/06/2005 14:15 +61-8-82723255 APT PAGE 27/45 3 positions. The slip clutch is in the form of axially aligned projections on a piston wherein the projections move axially in recesses formed in an inner wall of the valve body. When in the open or closed positions the projections on the piston are deformed and therefore moveable into adjacent recesses so that in the open or closed position the piston is rotatable and thus the risk of overtightening is reduced.

A problem with the prior art valves known to the inventor is that they are complicated in that they have a relatively large number of moving pieces and are relatively complex in construction, which makes them more difficult and expensive to manufacture. Further they are not adapted to be fitted to a range of fittings having different depths and therefore many of the known fluid flow valves are not transferable between fittings.

OBJECT OF THE INVENTION The object of this invention is to provide a fluid flow valve that obviates or alleviates any one of the above problems, or at least to provide the public with a useful choice.

20 SUMMARY OF THE INVENTION In a first aspect the invention could be said to reside in a fluid flow valve, the valve including a tubular body, a piston forming a fluid tight seal within the body, the piston having a sealing means positioned at a first end thereof, and the piston moveable axially within the body between a closed position whereby the sealing means forms a fluid light seal with an associated valve seat such that fluid flow is substantially prevented and a 30 fully open position whereby fluid is able to flow through the valve seat, the piston being in frictional engagement with the body such that rotation of the piston is inhibited when the piston is between the fully open and closed positions, a spindle rotatable with respect to the body but prevented from axial movement with respect thereto, the spindle being connected to a second end of the piston such that rotational motion of the spindle is converted into axial movement of the COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02 82/06/2005 14:15 +61-8-82723255 APT PAGE 28/45 4 piston between the fully open and closed positions, the piston having means for engaging with the spindle or valve seat at the fully open and closed positions overcoming the frictional engagement between the body and the spindle and allowing rotation of the piston relative to the body to thereby prevent further relative axial movement of the piston.

It will be understood that with a standard fluid flow valve rotation of the spindle in one direction will cause the piston to move into the closed position whilst rotation of the spindle in the opposite direction will cause the piston to move toward and into the open position. When the piston is in the fully open or closed position then extra torque applied to the spindle may force the piston to move further and this can lead to a jamming or locking of the piston with the spindle. In the fluid flow valve of the present invention the piston is substantially prevented from rotating within the body by way of forming a frictional fit with the body. However when the piston is in the fully open or the closed position the means for engaging with the piston prevents further axial movement of the piston and extra torque applied to the spindle may be transferred to a rotation of the piston within the body. In this way the piston may be prevented from locking onto the spindle when extra :torque is applied when the piston is in the open position, and the sealing means 20 may be prevented from overtightening onto the valve seat when extra torque is applied when the piston is in the closed position.

Preferably an external surface of the body has a male thread beginning at a second end and extending partway along the body such that the second end of the body may be screwed into a fitting which may include a tap fitting, a stopcock or any S. other fluid flow control means. The thread is preferably a right hand thread.

•In one form of the Invention a first end of the body has a central aperture therethrough into which the spindle is journalled for rotation. The spindle may be S* 30 prevented from moving axially with respect to the nut and body by a retaining means. The retaining means is in the form of a circlip which may be fitted into a circumferential groove in the spindle such that when the spindle is assembled in the body the circlip rests on an upper surface of the body. The spindle may also have a circumferential flange extending from an outer surface such that when the spindle is assembled in the body the flange rests underneath the upper surface of COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02 02/86/2005 14:15 +61-8-82723255 APT PAGE 29/45 the body to thereby prevent axial movement of the spindle upwardly with respect to the body.

In an alternative form of the invention an internal surface of the tubular body may have a female thread beginning at a first end of the body and extending partway into the body so that a nut can be threaded into the first end of the body, the nut having a central aperture through which a first end of the spindle is journalled for rotation. The thread is preferably a right hand thread. The spindle may be prevented from moving axially with respect to the nut and body by a retaining means. The retaining means may be in the form of a circlip which may be fitted into a circumferential groove in the spindle such that when the spindle is assembled in the nut the circlip rests on an upper surface of the nut.

A means for forming a fluid tight connection between the body and a tap fitting, stopcock or fluid control means may be fitted to the external surface of the body.

In one preferred form the means is an ring for fluid tight connection.

In a particularly preferred form of the invention a second end of the spindle is 2 threaded with a male thread. A complementary female thread is provided in a first 20 end of the piston such that the piston can be screwed onto the spindle. Preferably S" the handedness of the thread at the second end of the spindle is opposite the thread on the body of the valve. Preferably also the piston frictionally engages the body such that when the spindle is rotated the piston is prevented from rotating as a result of the friction between the piston and the body but the screwing action causes the piston to move up and down on the thread of the spindle.

In this preferred embodiment, as the valve is opened the piston moves up on the thread of the spindle to a point where an upper surface of the piston bears against a stop on the spindle so that the piston cannot be screwed any further up the 30 spindle. In this way the piston cannot move any further axially upon continued rotation of the spindle after the piston has reached the open position and therefore any further rotation of the spindle causes the piston to rotate in the body.

Likewise, as the valve is closed the piston moves down on the thread of the spindle to a point where the piston and sealing means bear down on the valve seat In this closed position the piston cannot move any further down axially and any COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02 02/06/2005 14:15 +61-8-82723255 APT PAGE 30/45 6 further rotation of the spindle causes the piston to rotate within the body, thus preventing overtightening of the valve.

In another form of the invention the means for engaging the spindle with the piston at the open and closed positions is in the form of first and second protrusions extending from the spindle such that the first protrusion bears against a key in the piston when the piston is in the closed position to substantially prevent further axial movement of the piston, and the second protrusion bears against the key when the piston is in the open position to substantially prevent further axial movement of the piston.

In still another form of the invention the means for engaging the spindle with the piston at the open and closed positions is in the form of first and second protrusions extending from the spindle and adapted to engage first and second keys extending from the piston.

Preferably when the piston is between the open and closed positions the friction between the piston and the body is greater than the torque applied to the spindle such that rotation of the piston is substantially prevented. In a particularly 20 preferred form the piston may have one or more circumferential grooves on an S* outer surface to accommodate one or more ring(s) to seal against the body and provide a friction fit with body. Optionally, at least one of the rings may have a castellated or wavy like outer surface that contacts the bore of the body and in this way the amount of friction between the piston and the body can be increased relative to the use of standard rings.

In a particularly preferred form of the invention an ring located proximal the second end of the piston and forms a fluid tight seal with the body, and a second ring having a wavy or castellated outer surface is located proximal the first end of 30 the piston and contacts the bore of the body to provide a friction fit between the body and the piston. The length of the second ring may be varied to adjust the amount of friction between the piston and body and hence the amount of torque required before the piston is able to rotate within the body.

In a preferred form of the invention the first end of the spindle extends beyond the nut and body and a handle may be fitted thereto by any of the known or COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02 82/06/2005 14:15 +61-8-82723255 APT PAGE 31/45 7 conventional methods for fitting handles to spindles of fluid flow valves.

Alternatively a motor may be fitted to the spindle so that the fluid flow valve can be, for example, electrically driven. The latter example may be used in industrial plants or other settings where electronic control of fluid flow is required.

In another form of the invention the threaded section on the second end of the spindle is divided into two sections with a non-threaded section therebetween.

The key in the piston may protrude into the non-threaded section such that spindle can be rotated when the key is in the non-threaded section but the threaded section can not rotate past the key. Thus the end of the thread of each threaded section acts as a stop and bears against the key.

In still another form of the invention the threaded section on the second end of the spindle is continuous and a first key in the piston protrudes into a non-threaded section of the spindle at a position above the thread whilst a second key in the piston protrudes into a non threaded section of the key at a position below the thread such that the threaded section cannot rotate past either of the keys. In this way an end of the threaded section bears against the first key when the piston is in the closed position such that further rotation of the spindle is transferred through the key into rotation of the piston. Similarly a distant end of the threaded section bears against the second key when the piston is in the fully open position such that further rotation of the spindle is transferred through the second key into rotation of the piston.

In one form of the invention the second end of the piston has a central aperture into which a cylindrical extension of the sealing means extends. In this way the sealing means may be journalled within the piston but not directly attached thereto. Thus when there is no fluid pressure acting on the sealing means and the piston is moved toward the fully open position the sealing means is not raised.

30 However under the circumstances of normal use of the valve the fluid pressure acting against the sealing means would force it to be raised more or less in unison with the piston. In this way if there was a backflow of fluid the backflow would act to force the sealing means back into sealing engagement with the valve seat, thus substantially preventing contamination of a main fluid source by back flow.

Thus the valve may act as a one way valve. Preferably the sealing means is a COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02 02/86/2005 14:15 +61-8-82723255 APT PAGE 32/45 8 standard washer as used in conventional tap fittings and the piston is adapted to accommodate those standard washers.

In another form of the invention the second end of the piston may have a circumferential flange extending therefrom to thereby form a cavity into which a sealing means of complementary shape to the cavity can be inserted. Preferably the sealing means is shaped and sized to fit snugly into the cavity and form an interference fit therewith so that the piston and sealing means move in unison.

The valve body, piston and spindle may be manufactured from any suitable material, including brass, stainless steel or plastic. It may not be necessary for each of the valve body, piston or spindle to be manufactured from the same materials.

In a second aspect the invention could be said to reside in a fluid flow control means, the control means including a body having an inlet and outlet with a fluid flow valve therebetween, 20 the fluid flow valve including a valve seat in fluid connection with the tap fitting such that fluid is able to flow i therethrough, 0 25 a tubular body, a piston forming a fluid tight seal within the body, the piston having a sealing means positioned at a first end thereof, and the piston moveable axially within the body between a closed position whereby the sealing means forms a fluid tight seal 30 with an associated valve seat such that fluid flow is substantially prevented and an fully open position whereby fluid is able to flow through the valve seat, the piston being in frictional engagement with the body such that rotation of the piston is inhibited when the piston is between the fully open and closed positions, a spindle rotatable with respect to the body but prevented from axial movement with respect thereto, the spindle being connected to a second end of the piston such that rotational motion of the spindle is converted into axial movement of the COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02 82/06/2005 14:15 +61-8-82723255 APT PAGE 33/45 9 piston between the fully open and closed positions, the piston having means for engaging with the spindle or valve seat at the fully open and closed positions overcoming the frictional engagement between the body and the spindle and allowing rotation of the piston relative to the body to thereby prevent further relative axial movement of the piston.

In a third aspect the invention may be said to reside in a valve mechanism for retro-fitting into an existing fluid control means having a valve seat, the mechanism including a piston forming a fluid tight seal within the body, the piston having a sealing means positioned at a first end thereof, and the piston moveable axially within the body between a closed position whereby the sealing means forms a fluid tight seal with an associated valve seat such that fluid flow is substantially prevented and a fully open position whereby fluid is able to flow through the valve seat, the piston being in frictional engagement with the body such that rotation of the piston is inhibited when the piston is between the fully open and closed positions, a spindle rotatable with respect to the body but prevented from axial movement 20 with respect thereto, the spindle being connected to a second end of the piston such that rotational motion of the spindle is converted into axial movement of the piston between the fully open and closed positions, the piston having means for engaging with the spindle or valve seat at the fully open and closed positions overcoming the frictional engagement between the body and the spindle and 25 allowing rotation of the piston relative to the body to thereby prevent further relative axial movement of the piston.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding the invention will now be described with reference to 30 an illustrated embodiment. The drawings describe an illustrated embodiment wherein, Figure 1 is part cross sectional view of a valve of a first embodiment the present invention fitted to a valve fitting and with the sealing means in the closed position, COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02 02/06/2005 14:15 +61-8-82723255 APT PAGE 34/45 Figure 2 plan view of an alternative ring for use with the valve of the present invention, Figure 3 is an isometric view of a second embodiment of a piston having a castelated ring spaced from a standard ring, Figure 4 is part cross sectional view of a valve of a second embodiment of the present invention fitted to a valve fitting and with the sealing means in the closed position, Figure 5 is a cross sectional view through 2-2' of Figure 4, Figure 6 is the same as Figure 4 but the spindle is rotated by about 270° and the piston and sealing means are in the open position, and Figure 7 is a cross sectional view through 44' of Figure 6.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT It will be appreciated that the accompanying drawings are sketches and not engineering design drawings. The intention is to assist understanding of the invention and so perspective or features may be distorted or omitted for clarity.

Throughout the drawings the same reference numeral will be used to refer to the same or similar feature.

25 It will be understood that the valve of the present invention is suitable for fitting to a range of tap fittings, stopcocks or other fluid flow control means for use in industrial, commercial or domestic applications. However for the purposes of S. illustration, the illustrated embodiment will be discussed in relation to a fluid flow valve for fitting to a tap fitting. The illustrations show a fluid flow valve for a 30 tap fitting The tap fitting has a valve seat onto which a sealing means in the form of a standard washer seats to prevent the flow of fluid.

A first embodiment of the invention is shown in Figure 1, whilst a second embodiment is shown generally in Figures 4 to 7.

COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02 02/06/2005 14:15 +61-8-82723255 APT PAGE 35/45 11 Referring to Figure 1, the fluid flow valve has a tubular body for fluid tight connection with the tap fitting. An external surface of the body has a male thread beginning at a second end of the body and extending partway along the body.

The threaded end is adapted to be screwed into a standard tap fitting. A sealing means in the form of an ring is fitted to the external surface of the body at a position adjacent the thread so that when the body is screwed into the tap fitting the ring presses against a shoulder of the tap fitting and forms a fluid tight seal. A circumferential flange protrudes from the external surface of the body and the flange is spaced from the second end of the body so that when the body is screwed into the tap fitting the flange is positioned above an upper surface of the tap fitting.

A piston (10) of 14 mm diameter forms a fluid tight seal within a 14.5 mm bore of the body The piston may has two circumferential grooves (11) on an outer surface to each accommodate an ring When fitted into the grooves the rings extend from the outer surface of the piston by about 1 mm. The "O" rings form a fluid tight seal between the piston and the body and they also frictionally engage the body. An alternative form of ring is shown in Figure 2 in which the outer surface of the ring has a castellated like appearance which 20 acts to increase the friction between the ring and the body. One or both of the O: rings (12) shown in Figure 1 can be replaced with the ring of Figure 2.

The piston is moveable axially within the body between a closed position as i shown in Figure 1, and a fully open position in which the piston and sealing S*means (in the form of a washer) are moved upwardly compared to Figure 1.

25 When the piston is in the closed position the sealing means forms a fluid tight seal with the valve seat to substantially prevent flow of fluid. When the piston is in the open position the seal may be raised from the valve seat by the pressure of fluid bearing on it and therefore water is able to flow through the tap fitting.

30 In a further alternative form that is illustrated in Figure 3, a standard ring (12) is fitted proximal the second end of the piston to form a fluid tight seal between the piston and the body. A second ring (12a) having a wavy outer surface is fitted within a groove located toward the first end of the piston. The wavy outer surface ncreases the amount of friction between the piston and body and hence the amount of torque required to turn the piston in the body. In one form the second ring is formed from an elastomeric material such as rubber and the outer diameter COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02 02/06/2005 14:15 +61-8-82723255 APT PAGE 36/45 12 of the ring can be adjusted to alter the degree of friction between the piston and body and hence the torque required to rotated the piston. Alternatively the second ring could be formed from a suitable metal such as stainless steel. The form illustrated in Figure 3 may be particularly suitable for hot fluid applications because the second ring is spaced from the hot fluid and hence the amount of heat degradation of the second ring can be minimised.

An elongate spindle (14) is coaxially aligned with the body and extends partway into the body. The spindle is rotatable with respect to the body but prevented from axial movement with respect thereto. An end (15) of the spindle is threaded with a left handed male thread (16) and a complementary female thread (17) is provided in a first end (18) of the piston such that the piston can be screwed onto the spindle. Rotation of the spindle causes the piston to move up and down between the open and closed position on the thread of the spindle. As the spindle is rotated in either direction between the fully open and closed positions the piston is prevented from rotation as a result of the friction fit between the piston and the body caused by the rings (12).

The thread (16) on the second end of the spindle is continuous and a flange (19) 20 extends outwardly from the spindle at a position above the thread In this way a first end (18) of the piston bears against the lower surface of the flange when the piston is in the open position such that further rotation of the spindle in a direction opposite arrow (22) is transferred through the flange and into rotation of the piston. When the piston is in the closed position as illustrated in Figure 1, 25 second end of the piston, through the sealing means, bears against the valve seat.

Continued turning of the spindle in the direction of arrow (22) when the piston is Sin the closed position causes the piston to rotate within the body because downward axial movement of the piston is inhibited by the valve seat.

30 An upper section of the body has a central aperture (27) through which the spindle *is journalled for rotation. A circlip (28) is fitted into a groove in the spindle and the flange (19) bears against a lower surface of the upper body so that the spindle is prevented from moving axially with respect to the body.

It will be understood that the length of the threaded sections of the spindle and piston are sufficient to allow the valve to be adapted to tap fittings, stopcocks or COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02 02/86/2005 14:15 +61-8-82723255

APT

13 other fluid flow control means having different depths between the valve seat and the thread into which the fluid flow valve is fitted. This mechanism may be useful in fittings where the valve seat has been reseated and the distance between the valve seat and the thread into which the fluid flow valve is fitted is increased over and above that which may be accommodated by the standard fluid flow valve.

An end (32) of the spindle extends beyond the nut and body and a handle (not shown) is fitted at that end. The handle can be fitted to the spindle by any of the known methods for fitting handles to fluid flow valves and preferably the first end of the spindle is configured the same as standard fluid flow valves which thus allows the fluid flow valve of the present invention to be retro-fitted to an existing tap fitting and for the existing handle to be reused.

A second end (33) of the piston (10) has a central aperture (34) into which a cylindrical extension (35) of the sealing means extends. The sealing means is journalled within the piston but not directly attached thereto. The length of the extension (35) is greater than the distance the piston moves between the fully open and closed position so that when the piston is in the open position and the sealing means is seated on the valve seat an upper portion of the extension remains in the 20 aperture (34).

When the piston is moved toward the open position the fluid pressure acting against the sealing means forces it to be raised with the piston. Should there be a backflow of fluid when the piston and sealing means are in the open position the 25 backflow would act to force the sealing means back into sealing engagement with the valve seat, thus substantially preventing contamination of the main fluid source by backflow. In this way the valve acts as a one way valve.

Referring now to a second embodiment of the invention depicted in Figures 4 to 7.

The fluid flow valve has a tubular body for fluid tight connection with the tap fitting. An external surface of the body has a male thread beginning at a second end of the body and extending partway along the body. The threaded end is adapted to be screwed into a standard tap fitting. A sealing means in the form of an ring is fitted to the external surface of the body at a position adjacent the thread so that when the body is screwed into the tap fitting the ring PAGE 37/45 COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02 02/06/2005 14:15 +61-8-82723255

APT

PAGE 38/45 14 presses against a shoulder of the tap fitting and forms a fluid tight seal. A circumferential flange protrudes from the external surface of the body and the flange is spaced from the second end of the body so that when the body is screwed into the tap fitting the flange Is positioned above an upper surface of the tap fitting.

A piston (10) forms a fluid tight seal within the body The piston may has two circumferential grooves (11) on an outer surface to each accommodate an ring The rings form a fluid tight seal between the piston and the body and they also frictionally engage the body. The piston is moveable axially within the body between a closed position, as shown in Figure 4, and an open position as shown in Figure 6. When the piston is in the closed position the sealing means (4) forms a fluid tight seal with the valve seat to substantially prevent flow of fluid. When the piston is in the open position the seal may be raised from the valve seat by the pressure of fluid bearing on it and therefore water is able to flow through the tap fitting.

An elongate spindle (14) is coaxially aligned with the body and extends partway into the body. The spindle is rotatable with respect to the body but prevented 20 from axial movement with respect thereto. An end (15) of the spindle is threaded with a left handed male thread (16) and a complementary female thread (17) is provided in a first end (18) of the piston such that the piston can be screwed onto the spindle. Rotation of the spindle causes the piston to move up and down between the fully open and closed position on the thread of the spindle. As Ihe 25 spindle is rotated in either direction the piston is prevented from rotation as a result of the friction fit between the piston and the body caused by the rings (12).

The thread (16) on the second end of the spindle is discontinuous and a key (20) in 30 the piston protrudes into a non-threaded section of the spindle such that the threaded section cannot rotate past the key. In this way a first end (21) of the threaded section bears against the key when the piston is in the closed position such that further rotation of the spindle in a direction opposite arrow (22) is transferred through the key into rotation of the piston, as best illustrated in Figure 5. Similarly a second end (23) of the threaded section bears against the key when COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02 02/06/2005 14:15 +61-8-82723255 APT PAGE 39/45 the piston is in the open position such that further rotation of the spindle in th.e direction of arrow (22) is transferred through the key into rotation of the piston.

In assembling the piston and spindle part of the flow valve the spindle (14) is screwed into the first end of the piston until the first end (21) of the threaded section is past a position into which the key (20) is to be fitted and the key is inserted into an aperture (not shown) in the piston.

A nut (24) has a threaded section (25) which is screwed into a complementary threaded end (26) of the body. The nut has a central aperture (27) through which the spindle is journalled for rotation. A circlip (28) is fitted into a groove in the spindle and the spindle is prevented from moving axially with respect to the nut by the circlip bearing against an upper surface of the nut. A biasing means in the form of a spring (30) bears at one end against an underside of the nut and at a second end it bears against a radial protrusion (31) extending from the spindle at a position below the nut The biasing means thus acts to bias the spindle downwards and the downward bias is restricted by the circlip (28) bearing against the nut. The biasing means is advantageous in that it pushes the spindle, piston and sealing means down toward the valve seat and thus provides an improved seal 20 with the valve seat. Further, the biasing means acts as a shock absorbing system and prevents water hammering that is caused by sudden pressure changes in the water system.

It will be understood that the combination of the threaded first and second ends of 25 the body as well as the nut provide a means for adapting the fluid flow valve to tap fittings, stopcocks or other fluid flow control means having different depths between the valve seat and the thread into which the fluid flow valve is fitted.

Thus with the piston and sealing means in a position equivalent to the closed position, the fluid flow valve may be screwed into the tap fitting, stopcock or 30 other fluid flow control means to a point where the sealing means rests on the valve seat The nut may then be tightened to the point where the scaling means forms a fluid tight seal with the valve seat. This mechanism may be useful in fittings where the valve seat has been reseated and the distance between the valve seat and the thread into which the fluid flow valve is fitted is increased over and above that which may be accommodated by the standard fluid flow valve.

COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02 02/06/2005 14:15 +61-8-82723255 APT PAGE 40/45 16 An end (32) of the spindle extends beyond the out and body and a handle (not shown) is fitted at that end. The handle can be fitted to the spindle by any of the known methods for fitting handles to fluid flow valves and preferably the first end of the spindle is configured the same as standard fluid flow valves which thus allows the fluid flow valve of the present invention to be retro-fitted to an existing tap fitting and for the existing handle to be reused.

A second end (33) of the piston (10) has a central aperture (34) into which a cylindrical extension (35) of the sealing means extends. The sealing means is journalled within the piston but not directly attached thereto. The length of the extension (35) is greater than the distance the piston moves between the fully open and closed position so that when the piston is in the open position and the sealing means is seated on the valve seat an upper portion of the extension remains in the aperture (34).

When the piston is moved toward the open position the fluid pressure acting against the sealing means forces it to be raised with the piston. Should there be a backflow of fluid when the piston and sealing means are in the open position the backflow would act to force the sealing means back into sealing engagement with 20 the valve seat, thus substantially preventing contamination of the main fluid source by backflow. In this way the valve acts as a one way valve.

S**I Various features of the invention have been particularly shown and described in connection with the exemplified embodiment of the invention, however, it must be 25 understood that these particular.arraogements merely illustrate and that the invention is not limited thereto and can include various modifications falling within the spirit and scope of the invention.

ql O ^q COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02

Claims (22)

1. A fluid flow valve, the valve including a tubular body, a piston forming a fluid tight seal within the body, the piston having a sealing means positioned at a first end thereof, and the piston moveable axially within the body between a closed position whereby the sealing means forms a fluid tight seal with an associated valve seat such that fluid flow is substantially prevented and a fully open position whereby fluid is able to flow through the valve seat, the piston being in frictional engagement with the body such that rotation of the piston is inhibited when the piston is between the open and closed positions, a spindle rotatable with respect to the body but prevented from axial movement with respect thereto, the spindle being connected to a second end of the piston such that rotational motion of the spindle is converted into axial movement of the piston between the fully open and closed positions, the piston having means for engaging with the spindle or valve seat at the fully open and closed positions overcoming the frictional engagement between he body and the spindle and allowing rotation of the piston relative to the body to thereby prevent further relative axial movement of the piston.

2. The fluid flow valve as in claim 1 wherein a first end of the body has a central aperture through which the spindle is supported for rotation.

3. The fluid flow valve as in any one of the preceding claims wherein an .25 internal surface of the tubular body has a female thread beginning at a first end of the body and extending partway into the body so that a nut can be threaded into the first end of the body, the nut having a central aperture through which a first 'end of the spindle is journalled for rotation. 30

4. The fluid flow valve as in either claim 2 or 3 wherein the spindle is prevented from moving axially with respect to the body by a retaining means.

The fluid flow valve as in claim 3 wherein the retaining means is in the form of a circumferential flange extending from an outer surface such that when the spindle is assembled in the body the flange rests underneath an upper surface of the body to thereby prevent axial movement of the spindle upwardly with COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02 02/06/2005 14:15 +61-8-82723255 APT PAGE 42/45 18 respect to the body and a clip which may be fitted into a circumferential groove in the spindle such that when the spindle is assembled in the body the circlip rests on the upper surface of the body or nut

6. The fluid flow valve as in any one of the preceding claims wherein a second end of the spindle is threaded with a male thread, a complementary female thread is provided in a first end of the piston such that the piston can be screwed onto the spindle, the handedness of the thread at the second end of the spindle being opposite the thread on the body of the valve.

7. The fluid flow valve as in claim 6 wherein the piston frictionally engages the body such that when the spindle is rotated the piston is inhibited from rotating as a result of the friction between the piston and the body so that the screwing action causes the piston to move up and down on the thread of the spindle.

8. The fluid flow valve as in either claim 6 or 7 wherein in operation as the valve is opened the piston moves up on the thread of the spindle to a point where an upper surface of the piston bears against a stop on the spindle so that the piston cannot be screwed any further up the spindle and as the valve is closed the piston 20 moves down on the thread of the spindle to a point where the piston and sealing means bear down on the valve seat such that in the closed position the piston cannot move any further down axially and any further rotation of the spindle causes the piston to rotate within the body, thus preventing overtightening of the valve.

9. The fluid flow valve as in any one of the preceding claims the means for engaging the spindle with the piston at the fully open and closed positions is in the form of first and second protrusions extending from the spindle such that the first :3 protrusion bears against a key in the piston when the piston is in the closed position to substantially prevent further axial movement of the piston, and the second protrusion bears against the key when the piston is in the fully open position to substantially prevent further axial movement of the piston.

The fluid flow valve as in any one of the preceding claims wherein the means for engaging the spindle with the piston at the fully open and closed COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02 02/86/2005 14:15 +61-8-82723255 APT PAGE 43/45 19 positions is in the form of first and second protrusions extending from the spindle and adapted to engage first and second keys extending from the piston.

11. The fluid flow valve as in any one of the preceding claims wherein the friction between the piston and the body is greater than the torque applied to the spindle such that rotation of the piston is substantially prevented when the piston is between the open and closed positions.

12. The fluid flow valve as in claim 1 lwherein the piston has one or more circumferential grooves on an outer surface to accommodate one or more "O" rings to seal against the body and provide a friction fit with body.

13. The fluid flow valve as in claim 12 wherein one of the rings uneven outer surface that contacts the bore of the body.

14. The fluid flow valve as in claim 11 wherein an ring is located proximal the second end of the piston and forms a fluid tight seal with the body, and a second ring having an uneven outer surface is located proximal the first end of the piston and contacts the bore of the body to provide a friction fit between the 20 body and the piston.

15. The fluid flow valve as in any one of claims 6 to 14 wherein the threaded section on the second end of the spindle is divided into two sections with a non- threaded section therebetween, the key in the piston protruding into the non- "25 threaded section such that spindle can be rotated when the key is in the non- threaded section but the threaded section can not rotate past the key, the end of the thread of each threaded section acts as a stop and bears against the key to thereby limit the axial movement of the piston. 30

16. The fluid flow valve as in any one of claims 6 to 15 wherein the threaded section on the second end of the spindle is continuous and a first key in the piston protrudes into a non-threaded section of the spindle at a position above the thread whilst a second key in the piston protrudes into a non threaded section of the key at a position below the thread such that the threaded section cannot rotate past either of the keys. COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02 02/06/2005 14:15 +61-8-82723255 APT PAGE 44/45

17. The fluid flow valve as in any one of the preceding claims wherein an external surface of the body has a male thread beginning at a second end and extending partway along the body such that the second end of the body may be screwed into a flow control apparatus.

18. The fluid flow valve as in claim 17 wherein a means for forming a fluid tight connection between the body and the fluid control means is fitted to the external surface of the body.

19. A fluid flow control means, the control means including a body having an inlet and outlet with a fluid flow valve therebetween, the fluid flow valve including a valve seat in fluid connection with the tap fitting such that fluid is able to flow therethrough, a tubular body, a piston forming a fluid tight seal within the body, the piston having a sealing means positioned at a first end thereof, and the piston moveable axially within the body between a closed position whereby the sealing means forms a fluid tight seal with an associated valve seat such that fluid flow is substantially S.

20 prevented and a fully open position whereby fluid is able to flow through the valve seat, the piston being in frictional engagement with the body such that s. rotation of the piston is inhibited when the piston is between the fully open and closed positions, a spindle rotatable with respect to the body but prevented from axial S 25 movement with respect thereto, the spindle being connected to a second end of the piston such that rotational motion of the spindle is converted into axial movement of the piston between the fully open and closed positions, the piston having means for engaging with the spindle or valve seat at the fully open and closed positions overcoming the frictional engagement between the body and the spindle and 30 allowing rotation of the piston relative to the body to thereby prevent further relative axial movement of the piston. A valve mechanism for fitting into an existing fluid control means having a valve seat, the mechanism including a piston forming a fluid tight seal within the body, the piston having a sealing means positioned at a first end thereof, and the piston moveable axially COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02 02/06/2005 14:15 +61-8-82723255 APT PAGE 45/45 21 within the body between a closed position whereby the sealing means forms a fluid tight seal with an associated valve seat such that fluid flow is substantially prevented and a fully open position whereby fluid is able to flow through the valve seat, the piston being in frictional engagement with the body such that rotation of the piston is inhibited when the piston is between the fully open and closed positions, a spindle rotatable with respect to the body but prevented from axial movement with respect thereto, the spindle being connected to a second end of the piston such that rotational motion of the spindle is converted into axial movement of the piston between the fully open and closed positions, the piston having means for engaging with the spindle or valve seat at the fully open and closed positions overcoming the frictional engagement between the body and the spindle and allowing rotation of the piston relative to the body to thereby prevent further relative axial movement of the piston.

21. A fluid flow valve substantially as hereinbefore described with reference to the illustrated embodiments.

22. A valve mechanism substantially as hereinbefore described with 20 reference to the illustrated embodiments. Dated this 2nd day of June 2005 S.* MILADIN IVANOVIC By his Patent Attorneys A.P.T. Patent and Trade Mark Attorneys COMS ID No: SBMI-01279684 Received by IP Australia: Time 15:13 Date 2005-06-02