AU2004229045A1

AU2004229045A1 - Anti-hammer fluid control valve

Info

Publication number: AU2004229045A1
Application number: AU2004229045A
Authority: AU
Inventors: Walter George Morrison
Original assignee: KARTERIA Pty Ltd
Current assignee: Combobulator Pty Ltd
Priority date: 2003-12-08
Filing date: 2004-11-12
Publication date: 2005-06-23

Description

AUSTRALIA

0Parents Act 1990 Z ORIGINAL COMPLETE SPECIFICATION STANDARD

PATENT

ANTI-HAMMER FLUID CONTROL VALVE 0 Invention Title: The following statement Is a full description of this invention, including the best method of performing it known to me:- 2

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0 ANTI-HAMMER FLUID CONTROL VALVE

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Background of the Invention This invention relates to mechanical valves of the type used for controlling the flow of ,n fluids in a pipe or other vessel. Valves of this type have an inlet, an outlet and a valve 0 or control part therebetween. Fluid flow may be controlled by means of a movable S valve member that opens, shuts or partly obstructs the valve or control port through C which the fluid may flow in the pipe or other vessel. An example of this type of valve is a conventional household water tap. Although the invention will be described in relation to a household tap, it is emphasised that the invention has far wider application to other types of mechanical valves.

Description of the Prior Art A conventional household water tap has a metal body having an inlet which may be connected to a domestic water reticulation system, an outlet and a passage therebetween. Within the passage is a valve port surrounded by an annular valve seat.

Means are provided which are operable to force a sealing means forming part of or carried by a movable valve member onto the valve seat to close the passage. On release of the force, water pressure at the inlet causes the movable valve member to move from the valve seat to allow water to flow to the outlet.

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0 The movable valve member may be a jumper valve which comprises a metal disc ci O having a stem projecting from its obverse face and carrying flexible sealing means on ,I its reverse face. The operating means may comprise a rotatable spindle passing through the tap body. Usually, the stem of the jumper valve is slidingly received .4 within a recess in the inner end of the spindle. When the tap is in an open position, the 0 stem of the jumper valve is capable of sliding movement in the recess.

N A conventional tap may be used to control the supply of mains-pressure water to, say, a nozzle. It often occurs that, in use, the water flow is greater than is required leading to a wastage of water. Because of the high cost of water, and in many places the j scarcity of water, this wastage can be a problem, particularly when the tap is used to control the supply of hot water.

Previously, there have been several proposals to restrict water flow through a conventional tap. One proposal provides a valve assembly to replace the conventional valve member. The valve assembly comprises a cylindrical housing having a base mounted on or adjacent the valve seat. An aperture in the base communicates with the valve port so that water from the inlet may flow into the housing. A movable valve member located in the housing is operable to close the aperture. The transverse dimension of the movable valve member relative to the diameter of the housing controls the flow rate to the outlet.

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Water reticulation systems may exhibit a phenomenon known as water hammer, a thump which results when the flow of water in a pipe is suddenly arrested, as when a N valve or tap is suddenly closed. When a movable valve member is suddenly closed, inflow of water to the tap is stopped and often a shock wave emanates from the inlet side of the movable valve member and travels back along the inlet pipe. The shock N wave may travel into the reticulation system and even into the mains and may cause damage such as splitting metal or plastic pipes and loosening metal fittings from Splastic pipes. Water hammer is prevalent in a reticulation system to which a washing machine or dishwasher is connected when a solenoid valve controlling water flow into the machine suddenly operates to stop the flow of supply water.

In some situations the tap controlling water supply to, for example, toilet systems, dishwashing machines, clothes washing machines and the like may be permanently left open. Where there is a washing machine, for example, upstream from an open supply tap and the machine is not operating, the solenoid valve is closed. Pressure on either side of the movable valve member of the open supply tap is approximately the same and the movable valve member may be in a closed position sitting on the valve seat, in an open position resting against the tap spindle or in a position therebetween.

When the solenoid valve opens, water from the inlet pipe flows past the movable valve member of the supply tap which is forced against the spindle, past the solenoid valve into the washing machine. When the solenoid valve suddenly closes, a shock

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C, wave often moves from the solenoid valve closing the movable valve member of the 0 z supply tap with a thump. In some circumstances, the movable valve member may move quickly up and down hammering on the valve seat and on the end of the spindle.

Some effects of the shock wave may pass the movable valve member before it closes.

0 N The problems with excess water flow and water hammer are exacerbated in the case of Shigh pressure mains supply and in the case of erratic supply pressure.

Description of the Invention It is an object of the invention to provide means to restrict the flow of fluid through a

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mechanical valve of the type described.

It is another object of the invention to minimise the effects of water hammer in a mechanical valve of the type described.

It is a further object of the invention to provide a valve assembly which may be fitted in a mechanical valve of this type to replace the conventional movable valve member, which valve assembly features both flow restricting and anti-hammer characteristics.

It is proposed to provide a valve assembly having anti-hammer characteristics for restricting flow of fluid through a mechanical valve having an inlet, an outlet, and a valve port therebetween which may be closed or opened to allow fluid to flow from 6

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0the inlet to the outlet. The valve assembly may comprise a cup-shaped housing having o> a side wall and a base at one end of the housing, an aperture in the base of the housing, z a movable valve member supported loosely within the housing with a narrow clearance between the internal surface of the side wall of the housing and the adjacent n surface of the movable valve member. The movable valve member is capable of

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movement axially of the housing into cooperation with the base of the housing to close the aperture. Surface irregularities are formed on at least one of the internal surface of 0 N the side wall of the housing or the adjacent surface of the movable valve member 0to sufficient to cause fluid flow therebetween to be turbulent.

The construction is such that, instead of the conventional movable valve member, the valve assembly can be mounted adjacent the valve port of a mechanical valve with the aperture in the base of the housing connected to the valve port in a watertight fashion so that fluid may flow from the inlet through the valve port and aperture into the housing and pass between the internal surface of the side wall of the housing and the adjacent surface of the movable valve member in a turbulent condition to the outlet and the movable valve member is operable to be forced into cooperation with the base of the housing to close the aperture to prevent fluid from the inlet of the mechanical valve entering the housing.

Preferably, the valve assembly also includes sealing means adapted to form a watertight connection between the aperture and the valve port when the valve assembly is mounted adjacent thereto.

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0- 7 O Preferably, the internal surface of the side wall of the cup-shaped housing is cylindrical and the movable valve member has a substantially cylindrical surface adjacent thereto.

0 Preferably, the surface irregularities in the internal surface of the side wall of the housing and/or the adjacent surface of the movable valve member are formed by a C, plurality of crenels or circular grooves running around the circular surface(s).

The invention also includes a mechanical valve having the valve assembly mounted adjacent the valve port thereof Brief Description of the Drawings The invention is explained in greater detail in the following description with reference to the accompanying drawings which illustrate a household tap incorporating a valve assembly having flow restricting and anti-water hammer characteristics according to the invention. In the drawings Fig. I is an exploded axial cross-sectional view of a household tap incorporating a valve assembly exhibiting flow restricting and anti-water hammer characteristics in accordance with one embodiment of the invention; 8 0 0 Fig 2 is an axial cross-sectional view of the assembled tap of Fig. I with the movable o valve member of the valve assembly in its closed position; z Fig. 3 is an axial cross-sectional view of the assembled tap of Fig. I with the movable ,n valve member of the valve assembly in an open position;

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Fig. 5 is an axial cross~sectional view of a valve assembly in accordance with a third embodiment of the invention.

Description of the Embodiments As illustrated in Fig. 1, a household tap comprises a hollow body I having an inlet 2 leading into body I and outlet 3 leading therefrom. Inlet 2 is preferably provided with suitable connecting means (not shown) such as an internal or external screw thread for attachment to a water pipe provided with a mating screw thread. Within body 1 is a circular valve port 4 between inlet 2 and outlet 3. Valve port 4 is surrounded by an annular valve seat 5. The open mouth of body I is provided with an internal screw thread 6 for mounting a valve actuating member.

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0 The mouth of tap body I is closed by a somewhat cylindrical member 7 having a screw O thread 8 on its external cylindrical surface, which thread 8 mates with screw thread 6.

z ,I Cylindrical member 7 has an axial bore extending therethrough. Rotatably mounted within the axial bore of cylindrical member 7 is a spindle 9 having a handle 10 fixed thereto at the external end of spindle 9 and an axial recess 11 located in the internal 0 end of spindle 9. To rotatably mount spindle 9 in the axial bore of cylindrical member S7, spindle 9 is provided with an external screw thread which mates with an internal N screw thread in the axial bore of member 7. The axial bore is preferably provided with a gland or other sealing means (not shown) to prevent leakage of water.

The conventional movable valve member is replaced by a valve assembly having both flow restricting and anti-water hammer characteristics. According to this embodiment of the invention, a valve assembly for mounting adjacent to valve port 4 comprises a movable valve member 13 and a cup-shaped housing 16 having a substantially cylindrical side wall and a base at one end. The movable valve member 13 comprises a substantially cylindrical member of any suitable material such as metal or plastic.

Projecting from its upper end (as shown) is an axial pin 12 which, when the tap is assembled as shown in Figs. 2 and 3, fits with a small clearance into the recess 11 and, when the valve assembly is in an open position, it is capable of sliding movement therein. Attached to the lower end of movable valve member 13 is a flexible sealing washer 14 of any suitable material such as leather, rubber or plastic. The extemrnal cylindrical surface of movable valve member 13 is crenellated, i.e. it has a plurality of 01 0 crenels or circular grooves 15 running around the cylindrical surface. Crenels 15 may o be machined in the cylindrical surface of movable valve member 13. The fu~nction of the crenellated surface will be later explained.

When the tap is assembled as shown in Figs. 2 and 3, movable valve member 13 is supported loosely within a cup-shaped housing 16 which may be of any suitable material such as metal or plastic.

The diameter of movable valve member 13 is slightly less than the internal diameter of cup-shaped housing 16 so that it fits within housing 16 with a narrow clearance between the internal cylindrical surface of the side wall of housing 16 and the adjacent surface of movable valve member 13. Movable valve member 13 is capable of axial movement within housing 16 into cooperation with the base. The base of housing 16 is provided with an aperture which is preferably surrounded by an externally projecting spout 17. As shown in Figs. 2 and 3, housing 16 is mounted on the valve seat 5 with spout 17 projecting into valve port 4. To provide a stable and watertight connection, housing 16 may be provided with sealing means 18 and 19 to fit between the base of housing 16 and valve seat 5 and between spout 17 and the cylindrical wall of valve port 4 respectively, to prevent leakage of water through port 4. That is, any water passing from inlet 2 to outlet 3 must pass within housing 16 and between the internal surface thereof and the adjacent surface of movable valve member 13.

o ~Alternatively, housing 16 and spout 17 may be made inerlyfrom suitable slightly flexible plastic material, in which case sealing means 18 and 19 are not necessary.

Adequate sealing is obtained by the plastic spout 17 being press fitted into valve port 4 with the base of housing 16 sitting on valve seat S In its closed position as shown in Fig. 2, sealing washer 14 is pressed firmly against ci the base of cup-shaped housing 16 closing the aperture in the base of housing 16 and ]O thus preventing any water from flowing from inlet 2, When spindle 9 is raised, inlet water at mains pressure lifts movable valve member 13 as shown in Fig.3 allowing water to flow through spout 17 between the internal surface of the side wall of housing 16 and the adjacent surface of movable valve member 13, to outlet 3. The flow of water at outlet 3 is dependant, inter alia, on the amount of clearance between the adjacent surfaces of movable valve member 13 and housing 16 and the amount of clearance is selected to restrict fluid flow therebetween. Due to the crenellated cylindrical surface of movable valve member 13 and the smooth internal surface of housing 16, the flow between those two surfaces is turbulent. An Increase in Inlet pressure causes greater turbulence but only marginally increases the volume of flow at the outlet. Thus, the valve assembly of the invention operates to restrict the flow at the outlet irrespective of whether the pressure at the inlet is low, high or changing erratically.

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012 O Because there is reduced flow passing movable valve member 13 when it is open, z sudden closure of movable valve member 13 would arrest a reduced flow from inlet 2 causing a smaller shock wave (if any) and reduced water hammer effects. In the case of a washing machine upstream of an open tap, the flow to the washing machine when

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the solenoid valve is open is slower. Sudden closure of the solenoid valve would cause Sa smaller shock- wave (if any) compared to the situation where there is no flow

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N restrictor. Any shock wave emanating from the solenoid valve reaching movable valve 13 before it closes would be dampened when passing the turbulent flow between adjacent surfaces of movable valve member 13 and housing 16.

In a modification, the cylindrical surface of movable valve member 13 is smooth and the internal surface of housing 16 is crenellated. Again, both surfaces may be crenellated.

In a second embodiment of the invention illustrated in Fig. 4, sealing washer 14 carried by movable valve member 13 is replaced by an annular flexible sealing member 24 resting on, or fixed to, the base of housing 16 and surrounding the aperture in the base.

The movable valve member 23 has rounded sealing edges 25 which, in a closed position, are forced against annular sealing member 24 which stops flow through spout

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13 O 17. Sealing edges 25 are rounded to minimise wear and damage of sealing member 24.

z The inlet end or underside (as shown) of movable valve member 23 is provided with a cavity forming a conical surge chamber 26. In the case of a metal movable valve member 23, surge chamber 26 may be formed by machining. Alternatively, movable

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valve member 23 may be moulded from a suitable plastics material. When movable valve member 23 is in an open position, flow from inlet 2 causes turbulence in conical IN recess 26. This evens out erratic inlet pressures as found in water supply systems.

Further, any shock wave caused by sudden closure of movable valve member 23 would be dampened by the turbulence in conical recess 26. When housing 16 and movable valve member 23 are made from a suitable plastic material, sealing member 24 may be omitted. Adequate sealing is obtained by rounded edges 25 sealing directly on plastic base of housing 16.

Where added protection from water hammer is required, movable valve member 23 may be spring loaded. A step 27 may be provided on the top side of movable valve member 23 to locate one end of a spring in position. The strength of the spring is selected to ensure quicker closure of movable valve member 23. If a positive back pressure is required, a spring of suitable strength should be fitted.

In the embodiment illustrated in Fig, 5, crenels 15 are machined in the inner wall of cylindrical housing 36 instead of in the cylindrical wall of movable valve member 33.

0 14 o In this embodiment, the base of housing 36 is separated from spout 37 by flexible 0-ring 34. Preferably, 0-ring 34 sits in opposed grooves in the base of housing 36 and near to top end (as shown) of spout 37. 0-ring 34 Is sufficiently large that it has to be 'in forced into position and forms a watertight seal between housing 36 and spout 37.

When mounted adjacent valve port 4, 0-ring 34 also forms a seal with rounded edges 8 35 of movable valve member 33 and with valve seat 5 surrounding the valve bore (not Nl shown). Preferably, 0-ring 34 has a flat upper sealing surface and a flat protrusion on its lower edge to take up any wear on the valve seat. If required, a suitably sized 0-ring 39 may be provided to form a seal with the bore of the valve port 4.

By using a valve assembly in accordance with this invention, an engineered flow rate may be obtained to meet prevailing circumstances. The flow rate Is principally determined by the clearance between the movable valve member and the housing Thus, the principal design choice is the diameter of the movable valve member to give the desired clearance.

A second important design consideration is the nature of the surface irregularities which cause the turbulent flow between the internal surface of the wall of the housing and adjacent surface of the movable valve member. A crenellated surface as described above is merely one example. Instead of separate crenels, a continuous groove such as a helical thread may be employed. The surface irregularities may comprise depressions

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0, O in or projections on the cylindrical surface(s).. The depressions and/or projections may z form a regular pattern or be random. The density of the depressions and/or projections is not crucial.. What is critical is that the surface irregularities are sufficient to cause n turbulent flow at all points around the circumference of the movable valve member. In 0 this regard, factors such as the size, pattern, kind, extent, etc. of the surface irregularities may be relevant. Selection is made on the basis of the likely inlet IN pressure characteristics so that an orderly flow at the outlet is achieved. Further, the surface irregularities should be such as not to hamper the movement of the movable valve member in the housingInstallation and/or replacement of the valve assembly of this invention may be performed as easily as in the case of conventional valves commonly in use. Parts may be readily changed to meet changed circumstances.

Further, a valve assembly of the invention may be fitted in any mechanical valve of the type described.

Other modifications within the scope of the invention will be readily apparent to a person skilled in the art.

Claims

1. A valve assembly having anti-hammer characteristics for restricting flow of fluid through a mechanical valve having an inlet, an outlet, and a valve port therebetween which may be closed or opened to allow fluid to flow from the inlet to the outlet, said O valve assembly comprising a cup-shaped housing having a side wall and a base at one end of the housing, an aperture in the base of the housing, a movable valve i member supported loosely within the housing with a narrow clearance between the internal surface of the side wall of the housing and the adjacent surface of the movable valve member, said movable valve member being capable of movement axially of the housing into cooperation with the base of the housing to close the aperture and having surface irregularities formed on at least one of the internal surface of the side wall of the housing or the adjacent surface of the movable valve member sufficient to cause fluid flow therebetween to be turbulent; the valve assembly being adapted to be mounted adjacent the valve port of a mechanical valve with the aperture in the base connected to the valve port.

2. A valve assembly as claimed in Claim 1, wherein the internal surface of the side wall of the cup-shaped housing is cylindrical.

3. A valve assembly as claimed in Claim 1 or 2, wherein the movable valve member has a cylindrical surface adjacent the internal surface of the side wall of the housing. 17 O O

4. A valve assembly as claimed in Claims 1, 2 or 3, wherein the housing has an external o spout projecting therefrom and surrounding the aperture, which spout is adapted to z I project into the valve port of the mechanical valve when the valve assembly is mounted adjacent thereto.

O A valve assembly according to Claim 4, wherein the spout is separately connected to the base of the housing by flexible means.

6. A valve assembly as claimed in Claim 4 or 5, wherein the spout is formed of slightly flexible material so that the spout is adapted to be press fitted into the valve port.

7. A valve assembly as claimed in any preceding claim including sealing means adapted to form a watertight connection between the aperture and the valve port when the valve assembly is mounted in a mechanical valve adjacent the valve port.

8. A valve assembly as claimed in any preceding claim including sealing means between the movable valve member and the base of the housing.

9. A valve assembly as claimed in any preceding claim, wherein the surface irregularities are formed on the internal surface of the side wall of the housing. 18 O O 010 A valve assembly as claimed in Claims 1 to 8, wherein the surface irregularities are o formed on the adjacent surface of the movable valve member. z 11 A valve assembly as claimed in any one of Claims 1 to 8, wherein the surface irregularities are formed on both the internal surface of the side wall of the housing O and on adjacent surface of the movable valve member. S12 A valve assembly as claimed in any preceding claim, wherein the surface irregularities comprise a plurality of crenels or circular grooves running around the surface(s). 13 A valve assembly as claimed in any one of Claims 1 to 11, wherein the irregularities comprise one or more continuous grooves in the surface(s). 14 A valve assembly as claimed in any one of Claims 1 to 11, wherein the surface irregularities comprise depressions in or projections on the surface(s). A valve assembly as claimed in any preceding claim, wherein the movable valve member is provided with a cavity in its inlet end forming a surge chamber. 16 A mechanical valve having mounted therein a valve assembly according to any preceding claim. 19 17 A valve assembly substantially as described and illustrated in Figs. 1 to 3, Fig. 4 or Fig. 5 of the accompanying drawings. 18 A mechanical valve substantially as described and illustrated in Figs. 1 to 3, Fig. 4 or Fig. 5 of the accompanying drawings. DATED this Ilth day of NOVEMBER 2004. KARTERIA PTY LIMITED By its Patent Attorney, PAUL KILDEA.