GB2253682A

GB2253682A - Fluid flow control arrangement

Info

Publication number: GB2253682A
Application number: GB9205548A
Authority: GB
Inventors: Paul Anthony Capener
Original assignee: SOUTH STAFFORDSHIRE WATER PLC
Current assignee: SOUTH STAFFORDSHIRE WATER PLC
Priority date: 1991-03-14
Filing date: 1992-03-13
Publication date: 1992-09-16
Anticipated expiration: 2012-03-13
Also published as: GB9205548D0; GB9105462D0; GB2253682B

Abstract

A conventional stop cock for domestic water supplies is modified in order to provide a substantially constant rate of flow through the stop cook over an anticipated range of inlet pressures. Upper and lower portions (13, 10) of the conventional stop cook are unscrewed and a body comprising a support (20) and a part (24) connected together, is secured between the portions (13, 10). The part (24) provides a seat (26) for a control element (14) to prevent flow from an inlet (11) to an outlet (12) of the lower portion (10) of the stop cock, the body providing a flow path between the inlet and the outlet, in which flow path is an elastomeric flow control device (35) which is deformable in response to a pressure on its upstream side to reduce flow and thereby. for a given operating position of the control element, provide a substantially constant rate of flow. <IMAGE>

Description

FLUID FLOW CONTROL VALVE ARRANGEMENT This invention relates to control valves for fluids, and in particular to stop cocks for domestic water supplies.

It is desirable that charges made for water supplies should reflect the level of water usage. Water use will depend on both the number of occupants and the type of water using equipment commonly employed. The cost of water meters and of their installation, as well as the costs of making readings, renders their use unattractive.

It is an object of the invention to provide a fluid flow control valve arrangement including a device which can readily be incorporated in a standard form of stop valve, and which will regulate fluid flow to a predetermined level. The invention also has as an object the provision of a method of modifying said stop valve to incorporate said device, in a convenient manner.

According to one aspect of the invention there is provided a method of modifying a stop valve which includes a first portion having an inlet and an outlet, and a second portion in which a control element is movable to engage a seat of said first portion to prevent flow from said inlet to said outlet, said method comprising mounting a part on said first portion, said part providing a passage through which fluid is constrained to flow between said inlet and outlet and including an elastomeric flow control device in a flow path between said inlet and outlet, said device being deformable in response to a pressure on its upstream side to reduce flow between said inlet and outlet, whereby for a given operating position of said control element a substantially constant flow through the modified stop valve is maintained.

In a particular embodiment, said part is mounted between said first and second portions and includes a seat engageable by said control element to prevent flow between said inlet and said outlet.

According to a further aspect of the invention there is provided a fluid flow control valve arrangement comprising a housing having an inlet and an outlet, a control element engageable with a seat to prevent flow between said inlet and outlet, and an elastomeric flow control device in a flow path between said inlet and said outlet, said device being deformable in response to a pressure on its upstream side to reduce flow between said inlet and said outlet, whereby for a given operating position of said control element a substantially constant flow through the valve arrangement is maintained.

In a preferred embodiment said housing comprises a first portion having said inlet and said outlet, a second portion within which said control element is axially movable, and a part mounted between said first and second portions, said part defining said seat.

The invention will now be described, by way example, with reference to the accompanying drawings, in which: Figure 1 is a longitudinal section through a conventional domestic stop valve, and Figure 2 is a corresponding section of the stop valve of Figure 1 modified according to the invention.

The conventional stop valve shown in Figure 1 has a first housing portion 10 provided with an inlet 11 and an outlet 12, and a second housing portion 13 in sealed and threaded engagement with the portion 10 and supporting a control element 14 in the form of a handle.

The element 14 includes a seal 15 which can be screwed down into engagement with a seat 16 on the portion 10, to isolate the outlet 12 from the inlet 13 and thus prevent flow thereto.

To effect the modification shown in Figure 2, the portion 13 is unscrewed from the portion 10 and replaced by a support 20 which has an externally threaded end 21 and stepped bore 22 which has an internal thread 23 remote from the end 21. A part 24 is sealingly secured to the support 20 by way of the thread 23, and has an internal thread 25 which sealingly receives the housing portion 13. An upper face 26 of the part 24 provides a seat for the seal 15. The part 24 has a stepped axial bore 27. A volume 28 between the face 26 and the housing portion 13 communicates with the bore 22 by way of ten equi-spaced flow passages or bores 29 which surround the bore 27, the bore 22 communicating with the outlet 12.

An apertured bush 30 is axially located in the bore 27 by a tube 31 which extends through the opening defined by the seat 16 in the housing portion 10, there being an annular clearance around the tube 31 where it passes through the lower part of bore 22 in support 20, which is connected to portion 10. A toroidal sealing ring 32 engages both the tube 31 and the side of the bore 27, and the tube 31 is axially located by a nylon bush 33 and a rubber sealing washer 34 which is engaged between the bush 33 and the seat 16. The axial dimensions of the parts are such that the washer 34 prevents flow through the seat 16 from the inlet 11 to the outlet 12.

The bush 30 contains a rubber flow control device 35 of the type available from AKRO Valve Company of Pevensey, England. The device 35 is mounted so as to be subject externally to the pressure in the inlet 11, so that an increase in the inlet pressure causes a decrease in the effective flow area of the device 35. The effect is that for a given operating position of the control element 14, the rate of fluid flow through the valve remains substantially constant over an anticipated range of pressures in the inlet 11.

In use, with the seal 15 lifted from the face 26, water flows from the inlet 12, through the tube 31, restrictor 35, and apertured bush 30, into bore 27 and volume 28, then through the bores 29 and thence through the annular space formed by the clearance between the tube 31 and part 20 to the outlet 12.

The control device 35 may alternatively be fitted in the flow path of a stop valve mounted on a commercially available (meter) manifold. In either case the device 30 will be selected from a range of such devices, to provide a selected maximum flow. A stop valve according to the invention will thereby enable management of water supply and/or demand to be limited to a level selected by a user, whereby an agreed fixed charge, dependent on the selected level, may be made.

Claims

1. A method of modifying a stop valve which includes a first portion having an inlet and an outlet, and a second portion in which a control element is movable to engage a seat of the first portion to prevent flow from said inlet to said outlet, said method comprising mounting a part on said first portion, said part providing a passage through which fluid is constrained to flow between said inlet and said outlet, and including an elastomeric flow control device in a flow path between said inlet and said outlet, said device being deformable in response to a pressure on its upstream side to reduce flow between said inlet and said outlet, whereby for a given operating position of said control element a substantially constant flow through the modified stop valve is maintained.

2. A method as claimed in Claim 1, wherein said part is mounted between said first and second portions and includes a seat engageable by said control element to prevent flow between said inlet and said outlet.

3. A method as claimed in Claim 2, wherein said second portion is unscrewed from said first portion, a screw threaded lower end of said part is engaged with a screw threaded part of said first portion and a screw threaded part of said second portion is engaged with a screw threaded upper end of said part.

4. A method as claimed in either Claim 2 or Claim 3, wherein a tube of said part is arranged to extend through an opening in said first portion defined by said seat, said tube defining at least part of said flow path.

5. A method as claimed in Claim 4, wherein said tube axially locates an apertured bush in a stepped bore in said part, the bush containing said flow control device.

6. A method as claimed in any one of Claims 2 to 5, wherein said part is formed of two components which are screw threadedly connected together and said second portion is connected to the one of said two components which has said seat.

7. A fluid flow control valve arrangement comprising a housing having an inlet and an outlet, a control element engageable with a seat to prevent flow between said inlet and said outlet, and an elastomeric flow control device in a flow path between said inlet and said outlet, said device being deformable in response to a pressure on its upstream side to reduce flow between said inlet and said outlet, whereby for a given operating position of said control element a substantially constant flow through the valve arrangement is maintained.

8. A control valve arrangement as claimed in Claim 7, wherein said housing comprises a first portion having said inlet and said outlet, a second portion within which said control element is movable, and a part mounted between said first and second portions, said part defining said seat.

9. A control valve arrangement as claimed in Claim 8, wherein a screw threaded lower end of said part is engaged with a screw threaded part of said first portion and a screw threaded part of said second portion is engaged with a screw threaded upper end of said part.

10. A control valve arrangement as claimed in either of Claims 8 and 9, wherein a tube of said part extends through an opening in said first portion defined by a seat, said tube defining at least part of said flow path.

11. A control valve arrangement as claimed in Claim 10, wherein said tube axially locates an apertured bush in a stepped bore in said part, the bush containing said flow control device.

12. A control valve arrangement as claimed in Claim 11, wherein the flow control device is mounted in said bush so as to be subject externally to inlet pressure, so that an increase in the inlet pressure causes a decrease in the effective flow area of the device.

13. A control valve arrangement as claimed in Claim 12, wherein said tube extends out of said part with an annular space therearound, which space communicates with said outlet to define part of said flow path.

14. A control valve arrangement as claimed in Claim 13, wherein said part is formed of two components which are screw threadedly connected together and said second portion is connected to the one of said two components which has said seat.

15. A control valve arrangement as claimed in Claim 14, wherein said one of the components has said stepped bore therein, the bore at one of its ends having a face therearound which forms said seat, and said one of said components has at least one flow passage communicating said annular space with a volume between said face and said second portion.

16. A control valve arrangement as claimed in Claim 15, wherein said stepped bore extends centrally through said one of the components and a multiplicity of said flow passages are provided surrounding said stepped bore.

17. A control valve arrangement as claimed in Claim 8 or Claim 9, wherein said part is formed of two components connected together.

18. A control valve arrangement as claimed in Claim 10, wherein the tube is axially located at said opening by a bush and is sealed to said opening to prevent flow through said seat in said first portion.

19. A method of modifying a stop valve substantially as hereinbefore described, with reference to, and as shown in the accompanying drawings.

20. A fluid flow control valve arrangement substantially as hereinbefore described, with reference to, and as shown in Figure 2 of the accompanying drawings.