GB2237358A

GB2237358A - Fluid flow control valve

Info

Publication number: GB2237358A
Application number: GB8923373A
Authority: GB
Inventors: Denis Kevin Charles Clarke
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1989-10-17
Filing date: 1989-10-17
Publication date: 1991-05-01
Also published as: GB8923373D0

Abstract

A valve has an inlet 11 and an axially aligned outlet 12 which are separated by a wall 17 in a stem 14. Ports 18, 19 in the stem 14 communicate with the inlet 11 and outlet 12 respectively. A third port 20 in the stem 14 can communicate with a second outlet 13. An axially slidable control element 21 surrounds the stem 14 and is movable against the bias of a spring 22 by pressure applied to a control port 24. In one limiting position of the element 21 the inlet 11 and outlet 12 are interconnected through the ports 18, 19 via an annular recess 28 and the port 20 is shut. In the other limiting position of the element 21 the outlets 12, 13 are interconnected through the recess 29 and the port 20. <IMAGE>

Description

FLUID FLOW CONTROL VALVE This invention relates to a fluid flow control valve and has as an object to provide such a valve in which fluid pressure drop through the valve is very small at flow rates for which the valve is intended. In a preferred embodiment flow enters and leaves the valve through axially aligned inlet and outlet.

According to the invention there is provided a fluid flow control valve comprising a housing having an inlet and first and second outlets, a ported stem supported in said housing and having a bore communicating with said inlet, a sleeve control element surrounding said stem and being movable between a first position in which said inlet is isolated from said first and second outlets and said outlets are interconnected, and a second position in which said first outlet communicates with said inlet and is isolated from said second outlet, means for biasing said control element towards one of said positions, and means for applying a pressure signal to said control element to urge the latter against said biasing means and towards the other of said positions.

An embodiment of the invention is shown by way of example only in the accompanying drawing, which is a longitudinal section through the valve.

The valve comprises a housing 10 having an inlet 11, a first outlet 12 and a second outlet 13. Sealingly supported in the housing 10 is a sleeve 14 having aligned axial bores 15, 16 which are separated by a wall 17. The bore 15 communicates with the inlet 11. A plurality of radial ports extend through the circumference of the bore 15 adjacent the wall 17 and a corresponding plurality of radial ports 19 extend through the circumference of the bore 16 adjacent the wall 17. A further port 20 extends through the circumference of the bore 16.

A sleeve control element 21 slidably surrounds the stem 14 and is biased by a spring 22 towards contact with an end face 23 within the housing 10. A fluid pressure signal can be applied through a passage 24 in the housing 10 to act on a land 25 of the element 21 to urge the latter against the spring 22 and towards contact with an abutment 26 on the stem 14. Suitable seals 27 are provided between the stem 14 and housing 10 and between the element 21 and housing 10. The inlet 11 may be provided with a filter element through which the fluid flow to the valve is constrained to pass.

The control element 21 is provided with an annular recess 28 which cooperates with the ports 18, 19 and with a further annular recess 29 which cooperates with the port 20 and can communicate with the outlet 13.

In the shut position (shown) of the valve the element 21 is urged against the face 23, in which position the recess 28 communicates only with the ports 19 and the recess 29 communicates with the port 20 and outlet 13.

The outlets 12, 13 are thus interconnected through the port 20 and recess 29. Application of a fluid pressure signal to the passage 24 acts on the land 25 to urge the element 14 against the spring and into contact with the abutment 26, in which position the land 28 interconnects the ports 18, 19 and the outlet 13 is isolated from the outlet 12. Fluid can thereby flow from the inlet 11 to the outlet 12 through the ports 18, 19 and recess 28.

Claims

1. A fluid flow control valve comprising a housing having an inlet and first and second outlets, a ported stem supported in said housing and having a bore communicating with said inlet, a sleeve control element surrounding said stem and being movable between a first position in which said inlet is isolated from said first and second outlets and said outlets are interconnected, and a second position in which said first outlet communicates with said inlet and is isolated from said second outlet, means for biasing said control element towards one of said positions, and means for applying a pressure signal to said control element to urge the latter against said biasing means and towards the other of said positions.

2. A valve as claimed in Claim 1 in which said inlet and said first outlet are axially aligned.

3. A valve as claimed in Claim 2 in which said stem has first and second axially aligned bores communicating with said inlet and said first outlet respectively, and a wall between said first and second bores.

4. A valve as claimed in Claim 3 in which said stem has first and second ports which communicate with said first and second bores respectively and which intercommunicate through a passage in said control element in said first position thereof.

5. A valve as claimed in Claim 4 in which said stem has a third port communicating with said second bore, and said control element has a further passage through which said third port can communicate with said second outlet in said second position of said control element.

6. A valve as claimed in any preceding claim which includes a filter device in a flow path between said inlet and said stem.

7. A valve substantially as hereinbefore described with reference to the accompanying drawing.