GB2256698A

GB2256698A - Flow control valve

Info

Publication number: GB2256698A
Application number: GB9212356A
Authority: GB
Inventors: Alan Thomas Wright; Peter Leversley
Original assignee: Carver and Co Engineers Ltd
Current assignee: Carver and Co Engineers Ltd
Priority date: 1991-06-15
Filing date: 1992-06-11
Publication date: 1992-12-16
Anticipated expiration: 2012-06-11
Also published as: GB9212356D0; GB9112957D0; GB2256698B

Abstract

A fluid flow control valve comprises an electrical coil 22, which is movable within a magnet 35A, 35B and a valve member 40, 40A which supports the coil 22 so as to be movable, upon energisation of the coil, to open an orifice. A ferromagnetic pan 41 on the valve member is attracted by the magnet to urge the valve member to close the orifice. <IMAGE>

Description

FLOW CONTROL VALVE This invention concerns valves for controlling the flow of fluids, such as liquid or gaseous fuels.

Solenoid valves are well known and generally comprise a valve member connected to a soft iron armature so as to be reciprocal in a valve body by electrical energisation or de-energisation of a solenoid coil provided on the body around the armature. Such valves are switchable, e.g. nonprogressive and are primarily suitable for use as on/off cocks.

To give progressive control of the flow of fluid it is known to use motorised valves in which a spindle is rotated by an electrical stepping motor to move a valve member to progressively open or close an orifice in a valve body.

However, in a comparison with solenoid valves, such motorised valves are slow to act and are expensive to construct.

An object of the present invention is to enable the problems on the one hand of non-progressive function and on the other hand of slow function and cost to be reduced or avoided.

According to the present invention there is provided a flow control valve comprising a valve body or casing, an orifice within the valve body or casing between a fluid inlet and a fluid outlet, a valve member movable to open and close the orifice, and a bias to urge the valve member to a closed position in which it closes the orifice, wherein the valve member carries an electrical wire coil which is exposed to the magnetic field of a static magnet connected to the valve body or casing so that electrical energisation of the coil urges the valve member to move against the bias so that the amount of opening of the orifice can be controlled by controlling the electrical energisation of the coil.

The magnet is preferably a permanent magnet.

The coil is preferably supported by a thin rigid cup connected to the valve member; and the coil is preferably connected by flexible leads to fixed terminals on a carrier secured to the body. The carrier preferably carries an electronic control device for energising the coil.

Part of the valve member is preferably accessible, for renewal of a valve seal, via the fluid outlet or the fluid inlet.

Not only is the valve rapid acting and relatively simple to construct, but it enables a number of other complex problems to be reduced.

Although the bias could be provided by a flexible diaphragm or a spring, from general valve technology, there are known problems inherent in employing springs and diaphragms in valves, such as the diaphragms becoming porous with age and use; and variable frictional forces arising from binding or rubbing of the springs in the valve bodies, making accurate control of the valve member movement difficult to achieve. Furthermore, in the aforementioned case of fuel flow control valves, problems can arise if the fuel supply pressure regulator is faulty so that the problems in accurate control of the valve member movement become critical in permitting excessively large or unduly small fuel flow under conditions where the valve opening is required to be relatively small.

To solve these problems the flow control valve of the present invention is further characterised in that the bias is provided by a ferromagnetic part of or on the valve member being attracted towards the magnet. Such a magnetically acting bias has some characteristics opposite to those of a spring bias in that the bias force decreases, instead of increasing, with valve opening, and the friction related problems are completely obviated; and is sufficiently reliable to avoid the need for a secondary bias such as that provided by the diaphragm.

For dual fuel valve requirements, the electronic control system is preferably switchable or programmable to provide energisation levels appropriate to the selected fuel and its related supply pressure.

The present invention further provides a flow control valve comprising a valve body or casing, an orifice within the valve body or casing between a fluid inlet and a fluid outlet, a valve member movable to open and close the orifice, and a bias to urge the valve member to a closed position in which it closes the orifice, wherein the valve member carries an electrical wire coil which is exposed to the magnetic field of a static magnet connected to the valve body or casing so that electrical energisation of the coil urges the valve member to move against the bias so that the amount of opening of the orifice can be controlled by controlling the electrical energisation of the coil, and characterised in that the bias is provided by a ferromagnetic part of or on the valve member being attracted towards the magnet.

Further problems of cost and complexity arise from the legal requirements concerning fuel flow control valves for certain uses, e.g. space heaters and water heaters, by which it becomes necessary to provide two distinct valves for shutting off the flow of fuel, for safety reasons in case one valve fails in the open condition.

To solve this further problem, a further valve member is preferably provided in the flow control valve of the present invention to close a further orifice and carries a further wire coil for controlling movement of the further valve member in a magnetic field provided by the or a further static magnet.

The orifices are preferably disposed at opposite ends of a fuel flow passage which extends in the static magnet or magnets.

The field is preferably provided by a permanent magnet device common to both valves.

The invention further provides a flow control valve assembly comprising a housing, and a plurality of valves in the housing, each valve comprising an electromagnetically movable valve member movable to open and close a respective valve orifice, and characterised in that the valve orifices are provided at the ends of a gas flow passage in a permanent magnet device which provides a magnetic field or fields attracting the valve members to closed positions in which they close the valve orifices. Each valve member preferably carries a respective wire coil which can be electrically energised to move the valve member from the closed position.

The housing is preferably secured to a carrier which locates the magnet device in the housing. The carrier preferably serves as a partition between an inlet chamber and an outlet chamber. The carrier also preferably carries leads for the electrical supply to the coils. Each valve member preferably has or carries a ferromagnetic part which is attracted by the magnet device to provide a or the valve closing bias.

The invention will be described further by way of example with reference to the accompanying diagrammatic drawings in which: FIGURE 1 shows the cross-sectional layout of a first embodiment of a valve of the invention; FIGURE 2 is a view similar to FIGURE 1 of a second embodiment of valve of the invention; FIGURE 3 is a view similar to FIGURE 1 of a third embodiment of valve assembly of the invention.

In the first embodiment, the valve comprises a valve body 10 defining an orifice 11 between an inlet chamber 12 and an outlet 13. A valve member 14 extends within the body through the orifice to a head 15 against which a rubber seal ring 16 is seated so as to be located in the outlet 13. A bias, to urge the valve member to a closed position (shown) in which the ring 16 seals the orifice, is provided by a ferromagnetic ring 17A clamped to the flange so as to be magnetically attracted to the magnet.

A carrier 19 carries fixed terminals 20 for flexible wire leads 21 connecting a coil 22 to an electronic control unit 23 mounted on the carrier, which is preferably in the form of a printed circuit board.

The coil is located on an aluminium cup or bobbin 24 which is secured by a nut 25 to the other end of the valve member so as to clamp the inner periphery of the ring 17A to the flange.

The coil on the bobbin extends within an annular cavity of a permanent magnet 26 of cup form, which is secured to the body by fasteners 27 to clamp spacers 2b against the carrier.

In use, fluid is supplied under pressure to the inlet chamber and is prevented from exiting via the orifice until the energisation of the coil is sufficient to overcome the bias provided by the magnetic attraction of the ring 17A.

Thereafter the valve member . is displaced downwards progressively with progressive increase in the voltage of energisation.

In the event of a failure resulting in loss of energisation of the coil, the valve will automatically shut by virtue of said bias. Additionally, in the first embodiment, sealing means incorporating seals, 19A and 19B is provided to prevent leakage from the inlet chamber.

In the event of a failure resulting in excessive energisation of the coil the valve member will be moved to a safety position in which a shoulder 29 substantially closes the inlet chamber side of the orifice, and to this end the shoulder may be provided with a further seal 29A, indicated in broken lines.

The second embodiment is in the form of a valve device incorporating tandem (series) valves each of which is functionally equivalent to the first embodiment. The device comprises a two part casing 30 (in which the parts are identical and are clamped to a carrier 31 provided with seals 32) having an inlet 33 and an outlet 34. The carrier 31 encircles, is secured and sealed to, and supports a permanent magnet 35 common to both valves; and serves as a sealing partition between an inlet chamber 36 and an outlet chamber 37. The magnet 35 has a central passage 38 provided at each end with a valve orifice 39. Each valve includes a valve member 40, a bobbin 24 clamped to the valve member by a ferromagnetic ring nut 41 and a lock nut 42, and a coil 22 on the bobbin around one portion of the magnet.The valve member 40 and nut 42 are accessible via the inlet or outlet to permit in situ adjustment of the valves, for which purpose each member 40 has a slot at its outer end to receive a tool. A valve seal 16 is provided on the valve member to close the orifice 39. Each bobbin 25 has ports 43 to facilitate flow between the passage and the chambers. The carrier serves as a circuit board to which the coil leads 21 are attached. The control circuit or electronic control system (not shown in FIGURES 2 and 3) may actuate either or both the valves in progressively, or may control either or both thereof as a simple "on/off" valve.As can be seen from FIGURE 2, in this embodiment the upper valve member is of plug form for use as an "on/off" valve, whereas the lower valve member has a frusto-conically tapered extension 40A or "needle" to serve as a metering valve or variable throttle valve, and in each case the positional relationship of the coil and valve member can be adjusted by rotating the externally male threaded valve member.

The third embodiment shown in FIGURE 3 is generally similar to the second embodiment but differs primarily in that instead of a single magnet 35 a magnetic device, comprising two magnets 35A, 35B, is employed, which magnets 35A and B are bonded or otherwise secured on opposite sides of the carrier 31 which has an aperture therein defining part of the passage 38.

Both the second and third embodiments may also be provided with safety means which prevents a massive escape of fuel, e.g. gas, in the event of features caused by excessive energisation of both coils. In the second embodiment the safety means comprises a seal 50 on the bobbin of the outlet valve to engage a shoulder 51 on the casing, whereas in the third embodiment the safety means comprises a head piece 52 on the inner end of the outlet valve member 40, with an optional seal 53, to engage an inner end part 54 of the valve orifice 39.

The invention is not confined to details of the foregoing example and many variations are possible within the scope of the invention. For example, the magnet or magnets may be replaced by an electro-magnet.

In the first embodiment a formation for engagement by a tool may be provided on the head to enable the valve member to be moved to an open position in which the seal can be withdrawn via the outlet for replacement with a new seal.

It will be readily appreciated that a valve device, e.g. a three or more way valve device, can be constructed by employing a magnet arrangement providing a branched (e.g. T or X shaped) passage, with, for example, one inlet valve and a plurality (e.g. 2 or 3) outlet valves (or vice versa) on the limbs of the magnet arrangement, and the present invention accordingly provides and includes such multiple valve variations of the valve device. The electronic control system may be switchable for selective energisation of particular combinations of valves.

The valve or valve device may be used for liquids or gases, or mixtures thereof.

Furthermore the invention includes within its scope and hereby provides valve apparatus or a valve having any novel feature disclosed herein or in the accompanying drawing, or any novel combination of features so disclosed, (irrespective as to whether such features are features of operation, construction, configuration or componentry).

Claims

1. A flow control valve comprising a valve body or casing, an orifice within the valve body or casing between a fluid inlet and a fluid outlet, a valve member movable to open and close the orifice, and a bias to urge the valve member to a closed position in which it closes the orifice, wherein the valve member carries an electrical wire coil which is exposed to the magnetic field of a static magnet connected to the valve body or casing so that electrical energisation of the coil urges the valve member to move against the bias so that the amount of opening of the orifice can be controlled by controlling the electrical energisation of the coil.

2. A valve as claimed in Claim 1 wherein the bias is provided by a ferromagnetic part of or on the valve member being attracted towards the magnet.

3. A valve as claimed in Claim 1 wherein a further valve member is provided to close a further orifice and carries a further wire coil for controlling movement of the further valve member in a magnetic field provided by the or a further static magnet.

4. A valve as claimed in Claim 3 wherein the orifices are disposed at opposite ends of a gas flow passage which extends in the static magnet or magnets.

5. A flow control valve comprising a valve body or casing, an orifice within the valve body or casing between a fluid inlet and a fluid outlet, a valve member movable to open and close the orifice, and a bias to urge the valve member to a closed position in which it closes the orifice, wherein the valve member carries an electrical wire coil which is exposed to the magnetic field of a static magnet connected to the valve body or casing so that electrical energisation of the coil urges the valve member to move against the bias so that the amount of opening of the orifice can be controlled by controlling the electrical energisation of the coil, and characterised in that the bias is provided by a ferromagnetic part of or on the valve member being attracted towards the magnet.

6. A flow control valve assembly comprising a housing, and a plurality of valves in the housing, each valve comprising an electromagnetically movable valve member movable to open and close a respective valve orifice, and characterised in that the valve orifices are provided at the ends of a fluid flow passage in a permanent magnet device which provides a magnetic field or fields attracting the valve members to closed positions in which they close the valve orifices.

7. A valve or valve assembly as claimed in any preceding claim wherein the or each magnet is a permanent magnet.

8. A valve or valve assembly as claimed in any preceding claim wherein part of the valve member is accessible, for renewal of a valve seal, via the fluid outlet or the fluid inlet.

9. A valve or valve assembly as claimed in any preceding claim wherein the coil is supported by a thin rigid cup connected to the valve member; and the coil is connected by flexible leads to fixed terminals on a carrier secured to the body.

10. A valve or valve assembly as claimed in Claim 9 wherein the carrier carries an electronic device for energising the coil.

11. A valve or valve assembly as claimed in Claim 10 wherein the electronic device forms part of a control system which is switchable or programmable to provide energisation levels appropriate to the fuel and its related supply pressure.

12. A valve assembly as claimed in Claim 6 or any one of Claims 7 to 11 as appended to Claim 6 wherein each valve member has or carries a ferromagnetic part which is attracted by the magnet device to provide the valve closing bias.

13. A valve assembly as claimed in Claim 9, 10 or 11 as appended to Claim 6 wherein the housing is secured to the carrier.

14. An assembly as claimed in Claim 13 wherein the carrier locates the magnet device in the housing.

15. An assembly as claimed in Claim 13 or 14 wherein the carrier serves as a partition between an inlet chamber and an outlet chamber.

16. An assembly as claimed in Claim 13, 14 or 15 wherein the carrier also carries leads for the electrical supply to the coils.

17. A valve or assembly as claimed in any preceding claim having safety means to obstruct the flow through the valve or one of the valves in the event of over-energisation of the coil or one of the coils.

18. A valve or valve assembly substantially as hereinbefore described with reference to FIGURE 1, 2 or 3 of the accompanying drawings.