FLOW CONTROL VALVE

Abstract: A valve assembly (1) comprising a housing (2) having an inlet (3) and an outlet (17), and an on/off valve (5) mounted in the housing (2), the said on/off valve (5) being movable between open and closed positions to permit or prevent flow of liquid from the inlet (3) to the outlet (17), wherein a selector (13) having an inlet (14) and an outlet (16) is movably mounted in the housing (2) such that movement of the selector (13) causes the outlet (16) thereof to move relative to the outlet of the housing (2). In one aspect of the invention a bypass is provided to maintain a minimal flow rate when the main supply has been cut off, for example providing for basic low level supply of water for hygiene purposes when the main supply has been suspended as a result of non-payment of charges or the like.

Description: Flow Control Valve Field of the Invention This invention relates to flow control valves, and in particular to flow control valves for use with mains, stored, or pumped water supplies. The invention also relates to valves having a bypass to enable fluid to flow from the upstream side of the valve to the downstream side thereof when the valve is closed, and to a fluid supply control system incorporating such a valve. Background of the Invention Due to financial and environmental considerations, there is an increasing de- mand for devices which save water and energy. Known water saving devices comprise valves which may be pilot operated, pressure operated, or directly operated. Different types of valve are chosen depending on fluid pressure, fluid condition, fluid temperature, and ambient temperature. Flow control devices are often fitted to valve outlets. One commonly used pilot operated water saving device comprises a valve that is closed by a diaphragm. Upstream of the diaphragm the valve is connected to a mains water supply. The diaphragm comprises two orifices: the first permits water from the mains supply to flow behind the diaphragm, whilst the second permits water to flow from one side of the diaphragm to the other on application of an electric current to a solenoid which causes a plunger to move and allow water to pass through the second orifice. This type of valve does not allow the actual volume of water passing through the valve to be regulated; it only provides an on/ off control. Furthermore, this type of valve does not provide for the positive displacement of the diaphragm away from its seat. This can result in the diaphragm remaining closed, when it should be open, and hence the demand for water not being met. Attempts have been made to provide a valve that in addition to providing for on/ off control also provides for control of the actual volume of water passing through the valve. However, it would appear that known valves are unable to open and close at low fluid supply pressures and maintain an accurate flow rate in addition to operating with medium fluid pressures if so desired, in particular when used in conjunction with pilot operated magnetic latching operators. However, due to the relatively low pressures used in mains water supplies, when pipes are constricted to reduce flow rates, cavitation tends to occur. Fluids are often supplied to users by fluid suppliers via pipelines entering directly into the site where the user requires the fluid. Examples of this are the supply of water and gas. Water for instance is fed through a network of pipelines by water companies, and each user is connected to the network. Generally, users are billed from time to time for the amount of water they have used, or for an estimated level of use. If users refuse to pay for the water they have used, the suppliers eventually cut off their supply of water. A small proportion of users find paying large bills from time to time difficult, due to their financial circumstances. It is often easier for such people to pay for their water as they use it. This is also the case for gas. Metering systems are available which open a valve to allow a fixed amount of fluid to flow through the valve and into a user's house when the metering system is charged with money or money's worth. Charging can be done by inserting a token of a certain value into the metering system, or electronically. Such systems are already used in the supply of gas. However, the supply of fluids such as water and gas for heating is not only gov- erned by the end user's ability to pay. Water and fuel for heating are regarded by society as being basic human necessities for survival. Cutting off water and gas supplies has health implications not only for those occupy properties cut off, but also for those in the vicinity of the properties. For example, if water supply is cut off, toilets cannot be flushed and general levels of hygiene cannot be maintained, which can result in public health problems. Because of this, if a water or gas company wishes to cut off a user's supply of fluid, it usually must go through a complex legal process. This is time- consuming, expensive and also stressful for the user of the fluid. Nevertheless, users do have their supplies of fluid cut off. It would therefore be desirable to produce a device which would overcome the problems of both the fluid suppliers and the end users. Summary of the Invention The invention provides a valve assembly comprising a housing having an inlet and an outlet, and an on/ off valve mounted in the housing, the said on/ off valve being movable between open and closed positions to permit or prevent flow of liquid from the inlet to the outlet, wherein a selector having an inlet and an outlet is movably mounted in the housing such that movement of the selector causes the outlet thereof to move relative to the outlet of the housing. The on/ off valve may comprise a diaphragm. Alternatively, the on/off valve may comprise a member having an orifice therein and a closing means moveable be- tween a first position in which the orifice is closed, and a second position in which the orifice is open. An actuation means to move the on/off valve between its open and closed positions may be provided. The actuation means may comprise a solenoid, or a mechanical linkage. The valve assembly may further comprise control means to operate the actuator automatically or remotely. The control means may sense pressure and/or flow, and provide the actuation means with a signal according to the sensed pressure and/or flow. The on/ off valve may be pilot operated. Preferably, the outlet of the selector is substantially elliptical or circular in cross- section. Advantageously, the outlet of the housing is substantially elliptical or circular in cross-section. The selector may be rotatabiy mounted in the housing. The selector is suitably provided with an indent or a protrusion engageable from outside the housing to move the selector. The valve assembly may further comprise means to limit the angle through which the selector may be rotated. The said means may comprise a screw located in the housing which passes through an elongate slot in a portion of the selector. Alternatively, the selector may be provided with a protrusion that engages with a slot in the housing. Advantageously, the means to limit the angle through which the selector may be rotated enables the selector to be locked in any desired position between dosed and fully open. Preferably, the selector may be rotated through up to 45 degrees. Preferably, the cross-sectional area of the selector outlet is less than the cross- sectional area of the selector inlet. ln one embodiment of the invention the underside of the diaphragm is provided with a guide member arranged to slide in the inlet of the selector. The guide member is suitably a vane. A plurality of guide members may be provided. The valve assembly may be provided with a filter. In another embodiment of the invention an isolator is removably attached to the inlet of the housing. The isolator may comprise a filter. The isolator may be provided with a cap which is removable to allow access to the said filter. The housing and/or the selector, and/or the isolator may be formed from a plastics material, and the plastics material is suitably an EDPM elastomer. The valve assembly may provided for operating pressures of 0.1 to 12 bar. In one embodiment of the invention, the housing is provided with an internal or external bypass port connecting the inlet and outlet of the housing. The bypass port allows fluid to flow from the inlet of the housing to the outlet thereof without passing through the selector. The valve assembly of the invention permits the volume of water flowing to an appliance, such as a urinal or a tap, to be controlled accurately, in addition to providing on/ off switching. The problems caused by cavitation downstream of the diaphragm are far less in the valve assembly of the invention than known valve assemblies. Furthermore, the valve assembly of the invention is configured so that the diaphragm is lifted positively off its seat. Additionally, control of the volume of water flowing through the valve assembly is simple, and the valve assembly is easy to maintain. Another aspect of the invention provides a valve assembly comprising a housing having an inlet and an outlet, and an on/ off valve mounted in the housing movable between open and closed positions to permit or prevent flow of fluid from the inlet to the outlet, the valve providing an orifice through which fluid may flow when in the said open position, wherein a bypass is provided to permit fluid to flow at a limited rate from the inlet to the outlet when the valve is in its dosed position. The maximum flow rate of fluid through the bypass is suitably a fraction of the maximum flow rate of fluid through the orifice of the on/ off valve in its open position. Preferably, the cross-sectional area of the bypass is a fraction of the cross- sectional area of the said orifice. More preferably, the cross-sectional area of the bypass is 1 to 10 % of the cross-sectional area of the orifice. Advantageously, the maximum flow rate through the bypass is 1 to 10 % of the maximum flow rate through orifice of the on/ off valve in its open position for given pressure, fluid and temperature conditions. The maximum flow rate of the fluid through the bypass may be less than 5 litres per minute, and preferably, the maximum flow rate of the fluid through the bypass is less than 1 litre per minute. The bypass may be provided internally or externally of the housing. The bypass suitably comprises a bore, a port, a pipe, or a tube. The bypass may comprise an orifice in the on/ off valve. Preferably, the bypass permits fluid to flow therethrough at a trickle. The on/ off valve may be held in a position where it is partially open. An actuator may be provided to move the on/ off valve between its closed and its open positions. The actuator may comprise a solenoid which may be remotely controllable. Yet another aspect of the invention provides a fluid supply control system comprising a valve according to the invention, an actuator to open or close the on/ off valve, a fluid metering means, and a credit control means, wherein the fluid metering means provides the credit control means with a signal characteristic of the amount of fluid me- tered, and in response thereto the credit control means assesses whether further credit is available or not and provides the actuator with a signal to open the valve if further credit is available, or to close the valve if further credit is unavailable. The credit control means may comprise a pre-payment meter which may be charged with credit by tokens, coins, or cards. Alternatively, the pre-payment meter may be charged remotely. The credit control means may be located remotely from the valve assembly, metering means and actuator, and the credit control means may receive and send signals by telecommunications means. The valve assembly of the invention permits fluid suppliers to control the supply of fluid to users, and to encourage users to pay for the fluid being supplied without needing to cut-off the said supply. This saves the time of workmen in cutting off and reconnecting supplies, since these tasks usually require workmen to go to the property being supplied and cut-off the supply manually. Furthermore, potentially dangerous confrontation between users being cut-off or re-connected and the workmen carrying out these tasks is avoided. The users benefit from the invention because they will not be disconnected. Even when the valve is in its closed position it will permit sufficient flow of fluid to allow those in the property supplied to survive. For example, water would pass through the bypass at a rate sufficient to provide the occupants of the said property with drinking water, water to wash themselves with and sufficient water to flush a toilet with, even if this required an occupant to collect water in a vessel such as a jug. Use of the valve and the fluid supply control system is not limited to the supply of domestic utilities such as water and gas, but could also be used in commercial situations where fluid is supplied through a pipeline, and where absolute cut-off of supply is highly undesirable. Brief Description of the Drawings In the drawings, which illustrate preferred embodiments of the invention: Figure 1 is a cross section of valve according to the invention; Figure 2 shows the selector on its own; Figure 3 is a detail drawing of the outlet of the selector; Figure 4 is an enlarged view of a part of the rim of the inlet of the selector; Figure 5 is a side view of the assembled valve; Figure 6 illustrates a partial cross-section of a valve according to another aspect of the invention; and Figure 7 is a block diagram of a fluid supply control system according to the invention. Detailed Description of the Preferred Embodiments Figure 1 shows a valve assembly 1 comprising a housing 2 having an inlet 3 and an outlet 17, there being a selector 13 rotatably mounted in the housing between the inlet 3 and the outlet 17. The selector 13 has an inlet 14 and an outlet 16. Shoulder 27 of the selector prevents downward movement thereof. The selector 13 is provided with a slot 15 into which a protruding portion 36 of a plate 35 may be inserted. The plate 35 is provided with a notch 37 which engages with an elongate slot 38. The slot 38 advantageously extends through 45 degrees, thereby allowing the selector to be moved between a position where outlets 16 and 17 are aligned to provide maximum flow, and a second position where the outlets 16 and 17 are not aligned thereby preventing flow through the selector 1 3. The plate 35 is provided with a slot 39 into which a screw-driver, or similar can be inserted so as to adjust the relative positions of the outlet 16 of the selector and the outlet 17 of the housing. Grooves 26 which are substantially semi-circular in cross-section are provided above and below the selector outlet 16. In use, each of these grooves receives a seal, for example an "O" ring, to prevent leakage around the selector 1 3. Diaphragm 5 is supported around its periphery by shoulders 28, and is pre- vented from moving upwards by retaining member 29. A clamp (not shown) is provided to hold the retaining member and the coil in position on the housing 1. The central portion of the diaphragm 5 is flat and rests on the rim of inlet 14 of the selector 13. The underside of the diaphragm is provided with a plurality of vanes 12. The vanes 12 prevent cavitation, function as guides, and prevent the build up of scale in the region of the diaphragm seat. The vanes 12 are located on the diaphragm 5 so that they slide on the inner wall of the selector 13. This ensures that the diaphragm moves away from the inlet 14 of selector 13 in a uniform manner. A jet 6 is shown extending downwardly from the underside of the diaphragm 5. A capped pin 8 slides inside the jet 6. A solenoid, comprising a magnetic latching coil 9 and a plunger 11 having a magnet 10 attached to the lower end thereof, is mounted above the diaphragm, the plunger 1 1 being housed in the retaining member 29. With no electric current applied to the coil 9, the plunger 1 1 remains in the position shown in Figure 1 and the pin 8 is in the position shown in Figure 1 , entry to the jet 6 is sealed and no water flows. A spring may be provided within the central portion of the retaining member 29 to hold the plunger 1 1 in the position shown in Figure 1. When an electric current is applied to the coil 9, the plunger rises, and due to the attraction between the magnet 10 and the head of pin 8, the pin rises to allow the passage of fluid through the jet. It can be seen that an orifice 7 is provided in the diaphragm 5. The purpose of orifice 7 is to allow water to flow from the conduit 4 and into the space between the upper side of the diaphragm and the retaining member 29. The inlet and outlet ends of the housing 2 are provided with attachment means 18, 19 respectively. An isolator 21 is releasably attachable to the attachment means 18, and permits the supply of fluid to the inlet 3 to be switched on or off by moving the lever 24 from to the on or off position. A seal 23 is provided between the isolator and the end of the housing 2, and inside the isolator there is a constriction 25 in which a filter 22 is mounted. Referring to Figure 3, it can be seen that an orifice is provided in the side of the isolator 21, and a cap 30 is provided to close the said orifice. Removing the cap 30 gives access to the filter 22 so that it may be removed and cleaned or replaced. In Figure 3, a locking nut 33 is also shown which holds the isolator 21 in place. Attachment means 19 is shown having a connector 20 fitted thereto, but any type of fitting may be attached to the attachment means 19 in place of the fitting shown. In use, the upstream end of isolator 21 is connected to a mains water supply. The handle 24 of isolator 21 is turned to an on position and water flows through the isolator and into the inlet 3 of housing 2. Water then flows up the inclined conduit 4 where it meets a portion of diaphragm 5. Water then seeps through the relatively small orifice 7 in the diaphragm 5. To open the diaphragm 5 the coil 9 of the solenoid is supplied with an electric current causing plunger 1 1 to move upwardly. This in turn lifts pin 8 away from its seat and allows water to pass through the jet 6. Due to the inlet to the selector 13 being of greater diameter than the outlet thereof, water cannot leave the selector chamber 31 as quickly as it enters the chamber. This quickly causes the pressure in the chamber 31 to rise above the mains pressure on the upstream side of the diaphragm, and hence causes the diaphragm 5 to be lifted off its seat, thereby allowing water to flow directly from conduit 4 into chamber 31. The diaphragm 5 may be removed and replaced by a plug having an orifice therein. The plunger 1 1 may be used to close off the orifice, and thereby prevent the flow of fluid from the inlet 3 to the outlet 17. The plug may be formed from plastics or metal, stainless steel for example. The ability to replace the diaphragm 5 with a non- flexible insert allows the valve assembly to be switched rapidly from pilot operation to direct operation. The flow of water through the chamber 31 may be selected from the range 0 to 80 litres per minute by rotating the selector 13. The outlet 16 of the selector 13, and the outlet 17 of housing 2 are both elliptical or circular in shape. By moving one outlet with respect to the other and hence adjusting the degree to which the two outlets are aligned, the volume of water flowing therethrough can be controlled. It has been found that by providing outlets of elliptical or circular shape, cavita- tion is reduced. It may be desirable for the outlet of the selector to be circular and the outlet of the housing to be elliptical or vice versa. Referring now to Figure 2, the selector 13 is shown in detail. The enlarged view of the outlet 16 in Figure 3 shows its elliptical shape, whilst the enlarged view of the rim 34 of the inlet 14 in Figure 4 shows that rather than being pointed, the rim 34 is in fact radiused. By radiusing the rim 34 the production of vortices at the inlet 14 is reduced. Referring now to Figure 6, there is shown a valve assembly 1 which is essentially the same as that shown in Figures 1 to 5, with the exception of the provision of a bypass constituted by bores 40 in the housing 2 at the inlet side and the outlet side with a pipe 41 connecting the bores together. Components which are the same as in Figure 1 bear the same reference numerals and will not be described here further. If the fluid supplier wishes to cut-off supply of fluid to the outlet side of the housing, for example a house, he arranges for the selector 13 to be moved to its second position in which the outlets 16 and 17 are not aligned thereby preventing flow through the selector 13. Fluid still flows from the inlet side to the outlet side of the housing 2, but only through the bypass 40, 41 , and therefore the amount of fluid flowing from the inlet side to the outlet side is much reduced. Where the fluid is water, the diameter of the bores 40 and the pipe 41 is suitably of such a size as to permit a flow rate of less than 1 litre per minute at normal mains water pressure. The selector 13 may be moved from its first to its second positions or to any position between the said first and second positions, by an actuator such as a solenoid which may be remotely controllable. The valve illustrated in Figure 6 is for exemplary purposes only. The valve of the present invention need not comprise a selector 13 which is movable relative to the housing 2 to control the flow of fluid passing through the valve assembly as described above, but could comprise any type of on/ off valve. Figure 7 illustrates a fluid supply control system 50 comprising a fluid supply pipe 51 having mounted therein a valve assembly 52 according to the invention, a metering means 53 connected to the pipe 51 by pipes 54 thereby permitting fluid passing through the pipe 51 to pass through the meter 53, a credit control means 55, and an actuator 56. Fluid flows into and through the pipe 51 in the direction indicated by the arrow marked X. To start the system, the credit control means 55 sends a signal to the actuator 56 to indicate that credit is available, and in response to that signal the actuator 56 opens the on/ off valve 52 mounted in the pipe 51. The fluid passing through the pipe 51 is metered by meter 53, which sends a signal or signals to the credit control means 55 to indicate the volume of fluid which has passed through the meter 53. The credit control means 55 converts the signal received from the meter into a monetary value. The credit control means 55 compares the monetary value with the credit available. If the monetary value is less than the credit available, the signal sent to the actuator 56 remains unchanged and the valve remains open and more fluid can be supplied. The credit control means 55 stores the monetary value. When the credit control means 55 next receives a signal from the metering means 53 the signal is converted into a monetary value. This monetary value is added to the stored monetary value, and the aggregate value is compared with the available credit. If the available credit has been reached and/or exceeded, the credit control means 55 sends a signal to the actuator which al- lows the on/ off valve to move to its closed position. Fluid may then only flow through the pipe via the bypass in the valve assembly 52, until such time as credit is available. The credit control means 55 and the metering means 53 may comprise a prepayment meter. Alternatively, the credit control means may be remote from the supplied prop- erty, signals being sent to and received from the credit control means using telecommunications means, for example microwaves.

Claims: Claims 1. A valve assembly comprising a housing having an inlet and an outlet, and an on/ off valve mounted in the housing, the said on/ off valve being movable between open and closed positions to permit or prevent flow of liquid from the inlet to the out- let, wherein a selector having an inlet and an outlet is movably mounted in the housing such that movement of the selector causes the outlet thereof to move relative to the outlet of the housing. 2. A valve assembly according to Claim 1 , wherein the on/ off valve comprises a diaphragm. 3. A valve assembly according to Claiml , wherein the on/ off valve comprises a member having an orifice therein and a closing means movable between a first position in which the orifice is closed, and a second position in which the orifice is open. 4. A valve assembly according to any preceding claim, further comprising actuation means to move the on/off valve between its open and closed positions. 5. A valve assembly according to Claim 4, wherein the actuation means comprises a solenoid. 6. A valve assembly according to Claim 4 or 5, further comprising control means to operate the actuator automatically or remotely. 7. A valve assembly according to any preceding claim, wherein the on/ off valve is pilot operated. 8. A valve assembly according to Claim 2, wherein the underside of the diaphragm is provided with a guide member arranged to slide in the inlet of the selector. 9. A valve assembly according to Claim 8, wherein the guide member is a vane. 10. A valve assembly according to Claim 8 or 9, wherein a plurality of guide members is provided. 11. A valve assembly according to any preceding claim, wherein the outlet of the selector is substantially elliptical or circular in cross-section. 12. A valve assembly according to any preceding claim, wherein the outlet of the housing is substantially elliptical or circular in cross section. 13. A valve assembly according to any preceding claim, wherein the selector is rotatably mounted in the housing. 14. A valve assembly according to any preceding claim, wherein the selector is provided with an indent or a protrusion engageable from outside the housing to move the selector. 15. A valve assembly according to any preceding claim, wherein the cross- sectional area of the selector outlet is less than the cross-sectional area of the selector inlet. 16. A valve assembly according to any preceding claim, further comprising a filter. 17. A valve assembly according to any preceding claim, wherein an isolator is removably attached to the inlet of the housing. 18. A valve assembly according to Claim 17, wherein the isolator comprises a filter. 19. A valve assembly according to Claim 18, wherein the isolator is provided with a cap which is removable to allow access to the said filter. 20. A valve assembly comprising a housing having an inlet and an outlet, and an on/ off valve mounted in the housing movable between open and closed positions to permit or prevent flow of fluid from the inlet to the outlet, the valve providing an orifice through which fluid may flow when in the said open position, wherein a bypass is provided to permit fluid to flow at a limited rate from the inlet to the outlet when the valve is in its closed position. 21. A valve assembly according to Claim 20, wherein the maximum flow rate of fluid through the bypass is a fraction of the maximum flow rate of fluid through the orifice of the on/ off valve in its open position. 22. A valve assembly according to Claim 20 or 21 , wherein the cross- sectional area of the bypass is a fraction of the cross-sectional area of the said orifice. 23. A valve assembly according to Claim 22, wherein the cross-sectional area of the bypass is 1 to 10 % of the cross-sectional area of the orifice. 24. A valve assembly according to any of Claims 21 to 23, wherein the maximum flow rate through the bypass is 1 to 10 % of the maximum flow rate through the orifice of the on/ off valve in its open position for given pressure, fluid and temperature conditions. 25. A valve assembly according to any of Claims 20 to 24, wherein the maximum flow rate of the fluid through the bypass is less than 5 litres per minute. 26. A valve assembly according to Claim 25, wherein the maximum flow rate of the fluid through the bypass is less than 1 litre per minute. 27. A valve assembly according to any of Claims 20 to 26, wherein the bypass permits fluid to flow therethrough at a trickle. 28. A valve assembly according to any of Claims 20 to 27, wherein the by- pass is provided internally or externally of the housing. 29. A valve assembly according to any of Claims 20 to 28, wherein the bypass comprises a bore, a port, a pipe, or a tube, or an orifice in the on/ off valve. 30. A valve assembly according to any of claims 20 to 28, wherein the bypass is provided by allowing a trickle flow through the on/ off valve in its closed position, the on/ off valve being held in a partially open position. 31. A valve assembly according to any of Claims 20 to 30, wherein an actuator is provided to move the on/ off valve between its closed and its open positions. 32. A valve assembly according to claim 31, wherein the actuator comprises a solenoid. 33. A valve assembly according to Claim 32, wherein the solenoid is remotely controllable. 34. A fluid supply control system comprising a valve according to any of Claims 20 to 33, an actuator to open or close the on/ off valve, a fluid metering means, and a credit control means, wherein the fluid metering means provides the credit con- trol means with a signal characteristic of the amount of fluid metered, and in response thereto the credit control means assesses whether further credit is available or not and provides the actuator with a signal to open the valve if further credit is available, or to close the valve if further credit is unavailable. 35. A fluid supply control system according to Claim 34, wherein the credit control means comprises a pre-payment meter chargeable with credit. 36. A fluid supply control system according to Claim 35, wherein the prepayment meter may be charged with credit by tokens, coins, or cards. 37. A fluid supply control system according to Claim 35, wherein the prepayment meter is remotely chargeable. 38. A fluid supply control system according to any of Claims 34 to 37, wherein the credit control means is located remotely from the valve assembly, metering means and actuator, and the credit control means receives and sends signals by telecommunications means.

Inventors: ELLACOTT JOHN, ELLACOTT, JOHN
Applicants: DART VALLEY SYSTEMS LTD, ELLACOTT JOHN, DART VALLEY SYSTEMS LTD., ELLACOTT, JOHN
Application year: 1998
Main classification: F16K31
IPC codes: F16K5, F16K31