GB2181520A

GB2181520A - Valves

Info

Publication number: GB2181520A
Application number: GB08624042A
Authority: GB
Inventors: David Charles Sampson
Original assignee: BOC Group Ltd
Current assignee: BOC Group Ltd
Priority date: 1985-10-10
Filing date: 1986-10-07
Publication date: 1987-04-23
Also published as: DE3634037A1; GB8525059D0; GB8624042D0; JPS62188877A

Abstract

The flow of fluid through a valve 1 is controlled by a spring 10 which can be compressed to reduce fluid flow from a inlet 6 to an outlet 8 by movement of the core 12 of a solenoid. In a modification two springs (30, Figure 2) control flow from an inlet to two outlets (27,28). <IMAGE>

Description

SPECIFICATION Improvements in and relating to valves The present invention relates to valves.

In the publication "Fluid Logic in Simple Terms" by Michael J. Moylan there is described a device which uses a close-coiled spring as a moving partforcontrolling the flow of a fluid. Afluid supply is applied to the spring through a restrictor and while the coils of the spring are closed no flow is possible and a pressure output is obtained. When a force is applied to deflectthe spring and open the coils no output is possible since the fluid escapes from the coils fasterthan it can be replaced through the restrictor.

The coil spring of this known device acts as a basic on/offelement.

In United States Patent 3513874, there is described a fluid flow control device which comprises a housing having an inletforfluid and an outlet for said fluid spaced from the inlet. A compression spring is accommodated within the housing between the inlet and the outlet. An adjusting screw is arranged to apply an axial force to one end of the compression spring to alterthe spacing between individual coils of the spring and thereby alterthe resistance to flow of thefluidfrom the inlettowardsthe outlet. This known fluid flow control device is adjusted by mechanical means in the form of a screw. Further, itcon trolsonlyasingleflowand isnotcapableofapporti- oning flow along different flow lines.

It is an aim of the present invention to provide a valve having a coil spring for regulating the flow of a fluid therethrough and in which means in the form of a solenoid is provided for exerting an axial force on the coil spring to a degree commensurate with a current applied to the solenoid.

It is a further aim ofthe present invention to provide a valve having coil springs which regulate the flow of a fluid therethrough between two outlets.

According to one aspect of the present invention, a valve comprises a housing having an inletforfluid and an outletforsaid fluid spacedfrom the inlet,a coil spring accommodated within the housing for controlling theflow of fluid from the inletto the outlet and movablemeansforexerting an axial force on the coil spring to alterthe spacing between individual coils and thereby alter the resistance to flow ofthe fluid from the inlet towards the outlet, in which the moving means is a solenoid having a core and a field coil, the core exerting a force on the coil spring to a degree commensurate with a current applied to the field coil of the solenoid.

According to a further aspect ofthe present invention, a valve comprises a housing having an inletfor fluid and two outlets for said fluid each spaced from the inlet, a coil spring associated with each outletfor controlling the flow of fluid from the inlet to said associated outlet and movable means for exerting an axial force on the coil springs to alter the spacing between individual coils of each coil spring and thereby alterthe resistance to flow of the fluid from the inlet towards the associated outlet.

Embodiments ofthe invention will now be described, byway of example, reference being made to the Figures of the accompanying diagrammatic drawings in which: Figure lisa valve according to the presentinven- tion; and Figure 2 is a proportional double ended valve according to the present invention.

As shown in Figure 1, a valve 1 includes a housing 2tooneend of which is attached a manifold block4.

The manifold block 4 has an inlet 6 and an outlet 8 spaced from the inlet 6.

Accommodated within the housing 2 is a coil spring 10 the coils of which surround the outlet 8. Immediately adjacent the coil spring loins a core 12forming part of a solenoid. The field coil 14 of the solenoid surrounds the housing 2.

In use, when the coils of the spring 10 are open, as shown, fluid will flowfrom the inlet 6 through the coils and out of the manifold block4 via the outlet 8.

When it is desired to adjustthe rate of flow of fluid passing through the valve 1 currentto the solenoid field coil 14 can be varied. For example when it is des ired to restrict the fluid flow the core 12 is moved to the right as shown thereby compressing the spring 10 and causing adjacent coils to move closer together. The coil spring 10 will thus provide a greater resistance to the flow of fluid from the inlet 6 to the outlet 8. In the ultimate, the current to the solenoid coil 14 can be such that the core 12 closes the coils and thus prevents flow offluid from the inlet 6to the outlet 8.

Referring nowto Figure 2 a valve 21 includes a housing 22 to one end of which is attached a manifold 24. The manifold block 24 has an inlet 26 and an outlet 28 spaced from the inlet 26. At its opposite end the housing 22 has a second outlet 27.

Accommodated within the housing 22 are two coil springs 30 each associated with a outlet 27,28. The coils of each spring 30 surround its respective outlet 27,28. Also arranged within the housing 22 between the springs 30 is a core 32 forming part of a solenoid the field coil 34ofwhich surrounds the housing 22.

In use, it will be apparent that in the position ofthe core 32 as shown fluid will flow via inlet 26 through the housing 22 and through the coils of the left-hand as shown spring 30 and exit via the outlet 27.

The fluid will be unable to exit from the outlet 28 since the coils of the spring 30 associated with that outletareclosed by the core 32.

It will be apparent that by exciting the field coil,the core 32 can be moved so that the closeness ofthe coils of the respective springs 30 can be varied to vary the fluid flow th rough their respective outlets 26, 27.

Asthe movement of the core 32 progressively closes the coils of one spring 30 associated without- let 28, so the coils of the spring 30 associated with outlet 27 are progressively opened thereby apporti- oning the flow of fluid between the outlets 27,28.

In both embodiments described above the springs 10,30 can be made of plastics material or plastics coated material. Alternatively, in many processes where corrosivefluids are being controlled then the springs could be manufactured from stainless steel.

However, where using steel springs interference fit seats and possibly the use of square cross-section wire may be needed to ensure a fluid tight contact between adjacent coils.

It has been found when a solenoid core of a suitable material, such as radio-metal, is used the flow characteristics through the valve may be made substantially linear over a desired flow range by careful selection of supply pressures and component dimensions. Although in the above described embodiments compression springs are used extension springs can also be used. In the instances where compression springs are used it has been found useful to use a sealing compound coating said spring coils.

Claims

1. Avalvecomprising a housing having an inlet forfluid and an outietforsaid fluid spaced from the inlet, a coil spring accommodated within the housing for controlling the flow offluid from the inlet to the outlet and movable means for exerting an axial force on the coil spring to alter the spacing between individual coils and thereby alter the resistance to flow of the fluid from the inlet towards the outlet, in which the moving means is a solenoid having a core and a field coil, the core exerting a force on the coil spring to a degree commensurate with a current applied to the field coil of the solenoid.

2. A valve as claimed in claim 1, in which thespr- ing is made from plastics material.

3. Valve as claimed in claim 1, in which the spring is coated with a plastics material.

4. A valve as claimed in claim 1, in which thespr- ing is treated with a fluid sealing compound.

5. Avalvecomprising a housing having an inlet forfluid and two outlets for said fluid each spaced from the inlet, a coil spring associated with each out letforcontrolling the flow offluid from the inletto said associated outlet and movable means for exerting an axial force on the coil springs to alterthe spacing between individual coils of each coil spring and thereby alter the resistance to flow ofthe fluid from the inlet towards the associated outlet.

6. Avalve as claimed in claim 5, in which the moving means is a solenoid having a core and a field coil, the core being accommodated within the housing and exerting an axial force on each coil spring to a degree commensurate with a current applied to the field coil, the arrangement being such that as one coil spring is progressively closed the other coil spring is progressively opened.

7. A valve as claimed in claim or6, in which the spring is made from plastics material.

8. Avalve as claimed in claim 5 or6, in which the spring is coated with a plastics material.

9. Avalve as claimed in claim5 or 6, in which the springis treated with a fluid sealing compound.

10. Avalve constructed and arranged substantially as hereinbefore described with reference to Figure 1 or Figure 2 of the accompanying drawings,