GB2176581A - Control of fluid flow - Google Patents

Abstract

A valve assembly 30 comprises control means responsive to supply of fluid to a control inlet 45 to operate valve means 39 in a main passageway 32-35. It is used in the preferred embodiment to control the rate of flow of water to a cistern (23, Fig. 1) in an automatic flushing system with respect to water usage in a supply line (11) to other appliances (12) and which is affectively independent from the supply line (21) leading to the cistern. A control valve (60) in the other supply line (11) delivers a flow of water to control inlet 45 via a control line (25) when water flows in line (11) to an appliance (12). Main inlet 35 of valve 30 is connected to line (21) and a diaphragm 42, or a piston, responds to flow of water in the control line to move valve 39 to allow flow, or increased flow, of water through main passageway 32-35 to the cistern from line (21). The rate at which the cistern flushes may thus be controlled with reference to the usage of hot water at hand basins. In a second embodiment a main valve means (160, Fig. 4) incorporates an auxiliary poppet valve (167) which acts as a pilot valve to effect opening of valve (160) when water flows to a control inlet (145). <IMAGE>

Description

SPECIFICATION Control of fluid flow In our patent specification No. 2,119,903 we have described and claimed a fluid flow control valve and a method of controlling an automatic flushing cistern for which said valve may be employed. In that specification, the valve described and claimed comprises an inlet, a first outlet and a second outlet, and fluid flow sensor means adapted to respond to flow of fluid between said inlet and said first outlet to permit of or increase flow between said inlet and said second outlet, and such a valve operates by responding to the existence of a flow to the first outlet by providing a flow (or increasing the rate of an existing flow) to the second outlet.

The control method described and claimed in that specification is one of altering the rate of supply of water to a cistern in an automatic flushing system comprising the steps of sensing the flow of water to other appliances in a water using area in which the system is located and permitting of, or increasing the rate of, flow to the cistern whilst flow of water to said other appliances is sensed.

In the specific embodiment described by way of example in that specification, this method is effected by connecting the first outlet of a flow control valve according to that invention to said other appliances, such as water taps provided on hand basins, whilst the second outlet is connected to the cistern of the automatic flushing system so that the rate at which the cistern fills, and hence the interval between successive flushings, is related to the amount of water usage elsewhere in the vicinity.

The control valve which is the subject of specification 2,119,903 is suitable for use where both the automatic flushing system and the additional appliances are fed directly from a common supply. However, in some installations the supply to the flushing cistern may be from a different branch of a common supply for the other appliances, or from a totally separate supply, especially where the other appliances are connected to a hot water supply system.

Accordingly, the present invention is concerned with a development of the method described and claimed in specification 2,119,903 and a valve suitable for use in that method, whereby the flow of water to the cistern is controlled by reference to the flow of water within the same water usage area, but in a supply line which is itself not used for the principal supply to the cistern.

With this in view, the first aspect of the present invention resides in a fluid flow control valve having a main inlet and a main outlet, a main passageway extending between said main inlet and main outlet, valve means arranged to control flow of fluid through said main passageway, a control inlet and control means responsive to the supply of fluid to the control inlet to operate said valve means.

in use, such a valve can serve as a slave valve with its control inlet connected to the second outlet of a main control valve as described and claimed in specification 2,119,903 whereby the supply of water to a cistern by way of the main inlet and outlet can be controlled relative to the water usage in a different supply line in which said main control valve is connected.

According to a second aspect of the present invention, we provide a water supply installation including a first water supply line connected to one or more water using appliances located within a water usage area, a second water supply line connected to an automatic flushing system located in said water usage area, said automatic flushing system being adapted to operate on the accumulation of a predetermined amount of water in a cistern, a main fluid flow control valve comprising an inlet, a first outlet and a second outlet, and flow sensor means adapted to respond to the flow of fluid between said inlet and said first outlet, which are connected in said first supply line, so as to permit of flow or an increase in flow between said inlet and said second outlet, and a slave valve having a main inlet connected in said second supply line, a main outlet leading to said cistern, a main passageway extending between said main inlet and main outlet, valve means arranged to control flow of water through said main passageway, a control inlet connected to said second outlet of said main control valve, and control means responsive to the supply of water to the control inlet to operate said valve means and thereby permit of flow or of an increase in flow through said main passageway to said cistern whilst said flow sensor means responds to flow of fluid in said first supply line.

The invention further resides in a method for controlling the rate of flow of water to a cistern in an automatic flushing system which is adapted to operate on the accumulation of a predetermined quantity of water in said cistern, comprising the steps of sensing the flow of water in a first supply line connected to one or more water using appliances located in a water usage area in which the automatic flushing system is located, and during such flow of water, permitting flow or an increase in flow in a second supply line connected to said automatic flushing system.

The slave valve of the second aspect of the invention (i.e. the valve according to the first aspect of the invention) may include a chamber to which the control inlet is connected, said chamber having therein an operating member which is movable in response to the establishment of fluid pressure within said chamber to operate said valve means. The valve means preferably comprises a closure element which is movable relative to a seating, the closure element being coupled mechanically to said operating member. The operating member may comprise a diaphragm or a piston.

The chamber may be provided with a relief outlet whereby pressure within the chamber is relieved when supply of water to the control inlet ceases. Such relief outlet may discharge directly from the valve or be in the form of a by-pass leading to the main outlet of the valve. A flow restricting constriction may be provided in association with the relief outlet to ensure that fluid pressure can build up in the chamber when water is supplied to the control inlet. When the slave valve is used in conjunction with a main valve as described above, the dimensions of such constriction should be such as to allow a rate of flow less than any corresponding flow restricting constriction in the main valve which controls the rate of flow to the second outlet thereof when the sensor means responds to flow to the first outlet thereof.

Preferably, the valve means in the slave valve operates as an on-off valve which is normally closed and is opened in response to pressure in the chamber. If a minimum flow is desired to be maintained at all times between the main inlet and the main outlet, a by-pass for the valve means can provided. Alternatively, the valve means may be arranged to operate only as a flow regulating valve without entirely shutting off flow through the main passageway, but in a preferred arrangement, a minimum flow to the cistern is maintained by way of the relief outlet of the valve.

In a preferred embodiment, the slave valve may incorporate a composite poppet valve which comprises a main valve poppet arranged to engage a main seating in the main passageway between the main inlet and the main outlet and an auxiliary poppet arranged to engage an auxiliary seating in an auxiliary passageway which by-passes the main seating, the arrangement being such that the auxiliary valve poppet is movable away from the auxiliary seating by the control means, e.g.

the diaphragm, and the main valve poppet is in turn thereby caused to move away from the main seating. Conveniently, the auxiliary valve poppet is disposed concentrically within the main valve poppet.

The auxiliary poppet may act to establish a flow which causes a relative pressure drop at one end of the main valve poppet whereby the latter moves away from the main seating.

For this purpose, the main valve poppet may operate partially in a chamber which is supplied with fluid from the main inlet through a pressure-reducing orifice when the auxiliary poppet is spaced from it seating.

These and other features of the present invention will now be described in more detail, with reference to a preferred embodiment which is given by way of example and is illustrated in the accompanying drawings, wherein: Figure 1 is a diagram showing how the invention may be applied to one water supply installation; Figure 2 is a sectional view of a slave valve utilised in the system shown in Fig. 1; Figure 3 is a sectional view of a main valve used in conjunction with said slave valve; and Figure 4 is a sectional view of an alternative embodiment of slave valve.

The water supply installation illustrated in Fig. 1 comprises two effectively separate systems 10 and 20. The first system 10 includes a water supply line 11, which may be connected to a hot water supply system, feeding taps provided at a number of hand basins 12.

The second system 20 includes a separate supply line 21 feeding an automatic flushing system 22 which includes a cistern 23 arranged to operate when a predetermined quantity of water has accumulated therein. It will be understood that the second system 20 will normally be connected tq a cold water supply so as to be effectively independent of the first system 10. However, whilst the first system is preferably connected to a hot water supply, it may alternatively, within the concept of the invention, be connected to the same cold water supply as the second system 20, but because the supply lines 11 and 21 constitute different branches of the supply system, they are effectively independent.

The supply of water from line 21 to the cistern 23 is controlled by means of a slave valve 30 which is operated by reference to a main control valve 60 connected on supply line 11, a control line 25 being provided to connect the main valve 60 with the slave valve 30.

The slave valve 30, as illustrated in Fig. 2, comprises a generally cylindrical body 31 having an axial bore 32 which at its lower end opens out into a main outlet 33 and intermediate its ends communicates with a radial bore 34 leading to a main inlet 35. The main inlet 35, radial bore 34, axial bore 32 and outlet 33 constitute a main passageway through which the flow of fluid is controlled by valve means comprising a spindle 36 carrying a sealing ring 37 and arranged slidably within the axial bore 32, and having at its lower end a carrier 38 supporting a sealing washer 39 which engages an annular seating 40 formed by the mouth of the axial bore 32 where it opens out into the outlet 33. The valve assembly is urged onto the seat 40 by means of a conical compression spring 41 arranged within the outlet 33 as shown. The main inlet 35 is connected to the supply line 21 and the outlet 33 is formed as a nozzle and is arranged, as shown in Fig. 1, to discharge di rectly into the cistern 23, although it will be appreciated that alternatively the outlet could be arranged for coupling to a pipe forming part of the supply line leading to one or more cisterns.

The upper end of the valve spindle 36 is connected to a flexible diaphragm 42 which closes a chamber 43 formed at the upper end of the bore 32. The chamber 43 is vented to the outlet 33 by bore 33a so that any pressure in the outlet is transmitted to the chamber 43 and the valve assembly as a whole is substantially balanced with regard to fluid forces arising from water supplied to the main inlet 35.

The housing 31 has assembled therewith a top member 44 which includes a control inlet 45 communicating with a control chamber 46 which is also closed by the diaphragm 42.

The chamber 46 has associated therewith a plug 47 which includes an axial bore 48 which communicates with a radial bore 49 through a flow restricting constriction 50. A filter element 51 is provided to prevent the constriction 50 becoming blocked if the water supply is somewhat contaminated, and the radial bore 49 is arranged to discharge directly downwardly at a relief outlet 52 and also into the cistern 23.

The arrangement is such that when a flow of water is established in control line 25, due to the constriction 50, fluid pressure builds up within the control chamber 46 to an extent sufficient to displace the valve assembly against the force of biasing spring 41 and thereby open the main passageway so as to allow fluid to flow along line 21, to which the inlet 35 is connected, and into the cistern 23.

Whilst the slave valve conveniently employs a diaphragm 42 for the purpose of moving the valve assembly, it will be appreciated that it would alternatively be possible to employ a piston which is slidable within the control cylinder 46. Likewise, whilst the valve washer 39 in the illustrated embodiment engages sealingly with the seating 40 in the slave valve, it would be possible to arrange for the valve assembly only to regulate the rate of flow between the main inlet 35 and outlet 33 without shutting it off entirely, and thereby maintain a predetermined minimum flow rate in this way.

To enable the slave valve to open in response to water usage at the hand basins 12, the control line 25 is connected at its other end to the main control valve 60 which is illustrated in Fig. 3.

The valve 60 comprises end members 63a and 63b defining a respective inlet 61 and a first (or main) outlet 64 which are aligned axially and connected in supply line 11 as shown in Fig. 1. The end member 63a also includes a radially arranged second outlet 62 which is connected to the control line 25 leading to the control inlet of slave valve 30.

A cylindrical body 65 is secured between the end members 63a and 63b by means of co-operating screw threads 66 and 67. The body 65 houses a movable member 68 which consists of a central piston having a head 69 and stem 70 which carries at its free end a valve washer 71. The piston 69 is secured within a sleeve 72 formed with a ring of apertures 73 adjacent to the piston head. The sleeve 72 fits within the cylindrical body 65 with radial clearance, and is urged by a coil spring 81 towards the end member 63a so that the valve washer 71 normally engages a corresponding seating afforded by the end member 63a.However, flow of fluid from the inlet 61 through the interior of the sleeve 72, apertures 73 and the body 65 and to first outlet 64 causes the piston member 68 to move away from the end member 63a and towards the opposite end member 63b into a position in which the apertures 73 register with a widened end portion 82 of the cylindrical body 65, in which through-flow of water is substantially unimpeded.

Whilst the piston member 68 is spaced away from the end member 63a, fluid is allowed to flow into an axial bore 90 which is normally closed by the valve washer 71, and thence through a radial bore 92 to the second outlet 62. Thus, water will be supplied through control line 25 whenever water is being drawn through line 11 at the hand basins 12. As soon as flow in line 11 ceases, the piston member 68 will return, under the force of spring 81, to close the bore 90. However, a slight flow to the first outlet 64 is permitted by virtue of the radial clearance between the sleeve 72 and cylindrical body 65 without displacing the piston member 68 away from the seating, so that a slow flow associated with, for example, a dripping tap, will not establish a flow in the control line 25.

The rate of flow to the second outlet 62 may be pre-set by means of an appropriate adjusting member (not shown) which provides a variable restriction in the passageway defined by bores 90 and 92. The flow rate allowed by this variable restriction should be greater than that allowed by constriction 50 in the slave valve 30 in order to ensure that pressure builds up in the control chamber 46 of the slave valve, as previously mentioned.

However, if desired, the variable restriction in the main valve 60 may be omitted.

In the embodiment illustrated in Fig. 3, a bleed passageway 95 housing a sintered filter 96 is provided to by-pass the axial bore 90 when the latter is closed by the valve washer 71, in order to maintain a predtermined minimum flow to the second outlet 62. The flow rate as determined by the filter 96 is arranged to be less than the maximum flow rate permitted by the constriction 50 in the slave valve 30 so that, in the absence of flow through the main valve 60 to the first outlet 64, the flow in the control line 25 is insufficient to operate the slave valve. However, the trickle of water along the control line 25 is allowed to escape through the relief outlet 52 of the slave valve and thereby serves to maintain a minimum flow rate to the cistern 23 at all times.Whilst, in the installation described the water supplied to control line 25 is derived from a hot water supply, it will be appreciated that the flow rate will be so low that the water delivered from relief outlet 52 of the slave valve will be substantially cold.

Instead of providing a by-pass in the control valve 60, it would alternatively be possible to provide a similar by-pass between radial bore 34 and outlet 33 of the slave valve.

It will be appreciated that the provision of the slave valve 30 enables the rate at which the cistern 23 fills to be controlled with respect to water usage on a supply line which is effectively independent of that which serves the cistern itself, and accordingly the controlling factor may be the usage of hot or cold water as most appropriate in any given installation.

In use, the system ensures that the cistern 23 is filled to the extent required for it to flush over a maximum time period determined by the minimum flow rate achieved in any of the ways described above. However, water usage on the adjacent supply line 11 causes a temporary increase in the rate at which water is supplied to the cistern so that the time required to fill the cistern decreases as water usage on line 11 increases so that the rate at which the cistern is caused to flush is correlated with the general rate of water usage in the area.

Fig. 4 illustrates an alternative embodiment of slave valve 130 which may be used in place of the valve 30. The valve 130 comprises a generally disc-shaped body 131 which is divided by a partition 132 into an inlet portion 133 and an outlet portion 134.

The partition affords an aperture 135 in which a seating member 140 is located. Opposite the seating member, on the inlet side of the partition, the body is formed with a cylindrical recess 136 in which one end of a poppet valve assembly 160 is slidably received. Opposite the seating member, on the outlet side of the partition, the body affords a chamber 137 which is closed by a diaphragm assembly 141. The inlet portion of the body is provided with a throttling screw 129 to regulate the maximum flow rate between the main inlet 138 and the main outlet 139. A cap member 142 holds the diaphragm assembly 141 in place and defines a control chamber 146. The cap member carries an inlet assembly 143 which affords a control inlet 145 at one end of a through bore 144 which is closed at its other end by a plug 147, itself formed with a bore 148.The inner end of the bore 148 is provided with a filter element 151 whilst the outer end of the bore 148 is formed as a flow-restricting constriction 150. A transverse bore 149 extends from bore 148 and into the chamber 146.

In use, the main inlet 138 is connected to supply line 21 and the control inlet 145 is connected to control line 25, the main outlet 139 and the outlet from the constriction 150 being arranged, as in Fig. 1, to discharge directly into the cistern 23.

As in the Fig. 2 embodiment, flow in the control line 25 causes pressure to be established in the control chamber 146 so as to move the diaphragm assembly 141 away from a shoulder 1 46a and into contact with the poppet valve assembly 160 to enable water to flow from the main inlet 138 to the main outlet 139 whilst the necessary pressure is maintained in the control chamber 146.

The poppet valve assembly 160 comprises a main valve poppet 161 which carries a valve pad 163 to engage against the seating member 140, and an O-ring seal 164 which is engaged within the recess 136. The valve poppet is urged towards the seating member 140 by a spring 162 so that, normally, the valve is "closed".

The poppet valve assembly 160 also incorporates an auxiliary valve poppet 167 which carries a valve pad 168 arranged to engage a seating 169 afforded internally of the main valve poppet 161. A spring 166 acts between the auxiliary valve poppet 167 and an apertured disc 165 which is carried by the main valve poppet 161, and against which the spring 162 acts.

As can be seen, the main valve poppet 161 includes a stem 171 which extends through the aperture of the seating 140 towards the diaphragm assembly 141, whilst the auxiliary valve poppet 167 includes a stem 177 which extends through a passageway 170 formed axially of the main valve poppet 161. As can be seen, the stem 177 protrudes beyond the end of the stem 171 when the auxiliary valve poppet 167 is in its position of closure relative to the seating 169 of the main valve poppet 161.

The main valve poppet 161 is formed with a radial passageway 172 whereby fluid pressure from the inlet portion 133 is communicated to the interior of a chamber 173 which is formed within the main poppet valve 161.

The area afforded by passageway 172 is appreciably less than the effective cross-sectional area of passageway 170, and since the outlet portion 134 is arranged to discharge through outlet 139 directly into the cistern 23, the chamber 137 on the downstream side of the poppet valve assembly 160 will not normally be full so that the pressure exerted on the diaphragm assembly 141 will normally be atmospheric. To maintain the diaphragm assembly 141 against the seating 146a, a light spring 174 is provided.

Thus, normally, slave valve 130 is in the condition as illustrated in Fig. 4 wherein the main flow path between inlet 138 and outlet 139 is closed by the main valve poppet 161 being held onto the seating member 140 under the influence of spring 162 and the inlet pressure which is established within chamber 173 by virtue of passageway 172. Similarly, the auxiliary valve poppet 167 is closed onto the seating 169 by means of the associated spring 167 and the inlet pressure within chamber 173.

When water is supplied along control line 25 to the inlet assembly 143, pressure in the control chamber 146 builds up due to the constriction 150 so that the diaphragm assembly 141 is moved away from the shoulder 146a. As it does so, the diaphragm assembly 141 first engages the protruding end of the stem 177 of the auxiliary valve poppet 168.

Spring 166 is such that the auxiliary valve poppet is allowed to move away from the seating 169 whilst the main valve poppet 161 is maintained in its position of closure by means of the associated spring 162. Accordingly, a flow of water is established from the inlet 138 into the chamber 173 through the passageway 172 which establishes a substantial pressure drop as water flows through passageway 170 to the outlet 139.

The difference in pressure between the inlet portion 133 and chamber 173, together with the difference in area between seating 140 and chamber 173 is such that there is a net force on the main valve poppet 161 which causes it to move away from the seating member 140, thereby opening the main flow passageway between the inlet 138 and the outlet 139. This opening force may be augmented by contact between the diaphragm assembly 141 and the end of the stem 171 of the main poppet valve 161. Whilst sufficient pressure is maintained in control chamber 146 to keep the diaphragm assembly in contact with the auxiliary valve poppet, water flows from supply line 21 through the slave valve 130 to the cistern 23.

When the supply of water to control line 25 terminates through operation of the valve 60, the pressure in control chamber 146 is gradually relieved through the constriction 150. The diaphragm assembly 141 is thus moved back into contact with the shoulder 146a by spring 174 so that the auxiliary valve poppet 167 closes onto seating 169, with the result that the net force exerted on the main valve poppet 161 causes it to close on seating member 140 and interrupt flow of water to the main outlet 139.

The system described above is capable of coping with a wide range of operating pressures. The majority of hot water systems are gravity fed with static pressure between 0.14-1 bar (2-15 psig), a minority are pumped systems in flats and offices operating at 2-3 bar (30-45 psig) and direct mains supplied systems working at 1-10 bar (15-150 psig). Cold water systems are normally mains fed at 1-10 bar (15-150 psig), however gravity systems must be allowed for probably down to static pressures of 0.5 bar. Accordingly, valve 60 connected in supply line 11 is designed to cope with this entire range of pressures, whereas the slave valves 30 or 130 respectively are designed to cope with pressures up to 3 bar and 10 bar whilst allowing for the worst combination in which the valve 60 is connected in a line which operates at the minimum pressure of about 0.14 bar and has to control a slave valve 30 or 130 supplied at the maximum likely pressure of about 3 bar or 10 bar respectively.

The features disclosed in the foregoing description, or the accompanying drawing, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims (40)

1. A fluid flow control valve having a main inlet and a main outlet, a main passageway extending between said main inlet and main outlet, valve means arranged to control flow of fluid through said main passageway, a control inlet and control means responsive to the supply of fluid to the control inlet to operate said valve means.

2. A valve according to Claim 1 including a chamber to which the control inlet is connected, said chamber having therein an operating member which is movable in response to the establishment of fluid pressure within said chamber to operate said valve means.

3. A valve according to Claim 2 wherein the valve means comprises a closure element which is movable relative to a seating, the closure element being coupled mechanically to said operating member.

4. A valve according to Claim 2 or Claim 3 wherein the operating member comprises a diaphragm.

5. A valve according to Claim 2 or Claim 3 wherein the operating member comprises a piston.

6. A valve according to any one of Claims 2 to 5 wherein the chamber is provided with a relief outlet whereby pressure within the chamber is relieved when supply of water to the control inlet ceases.

7. A valve according to Claim 6 wherein said relief outlet discharges directly from the valve.

8. A valve according to claim 6 wherein said relief outlet comprises a bypass leading to the main outlet.

9. A valve according to any one of Claims 6 to 8 wherein a flow restricting construction is associated with said relief outlet.

10. A valve according to any one of the preceding claims wherein the valve means operates as an on-off valve which is normally closed.

11. A valve according to Claim 10 wherein a by-pass for the valve means is provided to maintain a minimum flow to the main outlet.

12. A valve according to any one of Claims 1 to 9 wherein the valve means operates as a flow regulating valve without entirely shutting off flow through the main passageway.

13. A valve according to any one of the preceding claims wherein the valve means incorporates a composite poppet valve which comprises a main valve poppet arranged to engage main seating in the main passageway between the main inlet and the main outlet and an auxiliary poppet arranged to engage an auxiliary seating in an auxiliary passageway which by-passes the main seating, the arrangement being such that the auxiliary valve poppet is movable away from the auxiliary seating by the control means, and the main valve poppet is in turn thereby caused to move away from the main seating.

14. A valve according to Claim 13 wherein the auxiliary valve poppet is disposed concentrically within the main valve poppet.

15. A valve according to Claim 13 or Claim 14 wherein the auxiliary poppet acts to establish a flow which causes a relative pressure drop at one end of the main valve poppet whereby the latter moves away from the main seating.

16. A valve according to Claim 15 wherein the main valve poppet operates partially in a chamber which is supplied with fluid from the main inlet through a pressure-reducing orifice when the auxiliary poppet is spaced from its seating.

17. A water supply installation including a first water supply line connected to one or more water using appliances located within a water usage area, a second water supply line connected to an automatic flushing system located in said water usage area, said automatic flushing system being adapted to operate on the accumulation of a predetermined amount of water in a cistern, a main fluid flow control valve comprising an inlet, a first outlet and a second outlet, and flow sensor means adapted to respond to the flow of fluid between said inlet and said first outlet, which are connected in said first supply line, so as to permit of flow or an increase in flow between said inlet and said second outlet, and a slave valve having a main inlet connected in said second supply line, a main outlet leading to said cistern, a main passageway extending between said main inlet and main outlet, valve means arranged to control flow of water through said main passageway, a control inlet connected to said second outlet of said main control valve, and control means responsive to the supply of water to the control inlet to operate said valve means and thereby permit of flow or of an increase in flow through said main passageway to said cistern whilst said flow sensor means responds to flow of fluid in said first supply line.

18. An installation according to Claim 17 wherein the slave valve includes a chamber to which the control inlet is connected, said chamber having therein an operating member which is movable in response to the establishment of fluid pressure within said chamber to operate said valve means.

19. An installation according to Claim 18 wherein the valve means comprises a closure element which is movable relative to a seating, the closure element being coupled mechanically to said operating member.

20. An installation according Claim 17 or Claim 18 wherein the operating member comprises a diaphragm.

21. An installation according to Claim 17 or Claim 18 the operating member comprises a piston.

22. An installation according to any one of Claims 18 to 21 wherein the chamber is provided with a relief outlet whereby pressure within the chamber is relieved when supply of water to the control inlet ceases.

23. An installation according to Claim 22 wherein said relief outlet discharges directly from the valve.

24. An installation according to Claim 22 wherein said relief outlet comprises a by-pass leading to the main outlet.

25. An installation according to any of Claims 22 to 24 wherein a flow restricting constriction is associated with said relief outlet.

26. An installation according to Claim 25 wherein the dimensions of said construction are such as to allow a rate of flow less than that afforded by any flow restricting constriction in the control valve which determines the rate of flow to the second outlet thereof.

27. An installation according to any one Claims 17 to 26 wherein the valve means operates as an on-off valve which is normally closed.

28. An installation according to any one of Claims 22 to 27 wherein a minimum flow to the cistern is established through the second outlet of the control valve and the relief outlet of the control valve.

29. An installation according to Claim 27 wherein a by-pass for the valve means is provided to maintain a minimum flow to the main outlet.

30. An installation according to any one Claims 17 to 26 wherein the valve means operates as a flow regulating valve without entirely shutting off flow through the main passageway.

31. An installation according to any one of Claims 17 to 28 wherein the valve means incorporates a composite poppet valve which comprises a main valve poppet arranged to engage a main seating in the main passageway between the main inlet and the main outlet and an auxiliary poppet arranged to engage an auxiliary seating in an auxiliary passageway which by-passes the main seating, the arrangement being such that the auxiliary valve poppet is movable away from the auxiliary seating by the control means, and the main valve poppet is in turn thereby caused to move away from the main seating.

32. An installation according to Claim 31 wherein the auxiliary valve poppet is disposed concentrically within the main valve poppet.

33. An installation according to Claim 31 or Claim 32 wherein the auxiliary poppet acts to establish a flow which causes a relative pressure drop at one end of the main valve poppet whereby the latter moves away from the main seating.

34. An installation according to Claim 33 wherein the main valve poppet operates partially in a chamber which is supplied with fluid from the main inlet through a pressure-reducing orifice when the auxiliary poppet is spaced from its seating.

35. A method for controlling the rate of flow of water to a cistern in an automatic flushing system which is adapted to operate on the accumulation of a predetermined quantity of water in said cistern, comprising the steps of sensing the flow of water in a first supply line connected to one or more water using appliances located in a water usage area in which the automatic flushing system is located, and during such flow of water, permitting flow or an increase in flow in a second supply line connected to said automatic flushing system.

36. A water supply installation substantially as hereinbefore described with reference to and as shown in Fig. 1 of the accompanying drawings.

37. A method of controlling the rate of flow of water to a cistern as claimed in Claim 35 and substantially as hereinbefore described.

38. A fluid flow control valve substantially as hereinbefore described with reference to and as shown in Fig. 2 of the accompanying drawings.

39. A fluid flow control valve substantially as hereinbefore described with reference to and as shown in Fig. 4 of the accompanying drawings.

40. Any novel feature or novel combination of features disclosed herein and/or as shown in the accompanying drawings.