GB2291540A - Solenoid valves - Google Patents

Abstract

The valve comprises a housing 7, (9, Fig 2) which forms a magnetic circuit having a gap therein, a pivotal 11 movable in response to energisation of a winding 8 to close the gap, and a rod 13 operated by the armature to move a diaphragm 6 into engagement with a nozzle 4. Screw threads 5 and 10 enable adjustment of the nozzle and sleeve (9). <IMAGE>

Description

SOLENOID VALVE DESCRIPTION This invention relates to solenoid valves.

With the increased use of electrical ring circuits, bus lines and the like, which can operate at low power and are hence particularly useful in hazardous environments, a need has arisen for reliable solenoid valves that can operate in consequence of a low voltage change in the applied signal.

In other words it is desirable to provide a device that provides a flow path for liquids or gases which can be interrupted (or connected) by the application of a low electric current.

According to one aspect of this invention there is provided a solenoid valve comprising first means to form a magnetic circuit having a gap therein, second means relatively movable with respect to said first means magnetically to close said gap, a solenoid winding to effect magnetisation of the first and/or the second means to produce said relative movement, and valve operating means responsive to said relative movement to operate the valve.

Preferably the first means comprises a double-walled chamber of magnetisable material containing said solenoid winding between its walls, said walls being interconnected at one end of the chamber. Optionally, at least one of the walls is discontinuous.

Advantageously, the second means comprises a plate member of magnetisable material to overlie (and extend at least partially across) the other end of said chamber.

Preferably the plate member is pivoted by one edge upon said casing. This aids in minimising solenoid power consumption.

Advantageously the effective length of one of the walls of said double-walled chamber is adjustable (e.g. by screwthreaded means) to vary the chamber's magnetic effect upon the plate member.

Preferably the valve operating means comprises an elongate operating member extending internally of the inner wall of the chamber beyond each of its said ends, one end of the operating member being engageable with part of the valve and the other end of the operating member being engageable by said plate member. Said part may be a valve closure member (e.g. a pad or a flexible diaphragm) engageable with a fluid inlet port and/or a fluid outlet port.

Preferably the (or each) port engageable by the valve closure member is provided by a unit positionally adjustable (e.g. by screw-threaded means) with respect to a housing for the solenoid valve.

According to another aspect of this invention there is provided a solenoid valve comprising: a housing of non-ferrous material, fluid inlet means to the housing, fluid outlet means from the housing, valve means to render said inlet means into and out of communication with said outlet means, a hollow container of magnetisable material within said housing, said container having an open top and containing a solenoid winding, an elongate valve operating member of non-ferrous material extending through the container, and a plate member of magnetisable material supported by the valve operating member to form a magnetic closure or "keeper" to the container's open top such that energising the solenoid magnetises the container and draws towards it said plate member to move said elongate valve operating member longitudinally such as to operate said valve means.

Preferably the fluid inlet means and/or outlet means controlled by said valve means is positionally adjustable, e.g. by screw-threaded means, with respect to said housing.

Advantageously the inner wall of said container is positionally adjustable, e.g. by screw-threaded means, with respect to the remainder of said container.

Preferably said plate member is loosely mounted upon the valve operating member and has one edge resting upon an outer edge of said container to provide a pivot for the plate member.

This, in effect, provides a so-called mechanical advantage by providing upon the valve operating member a leveraged magnification of the magnetically induced movement of the plate member. Thus a useful valve operating movement can be obtained from a low power electrical input signal to the solenoid. With a view to maximising this effect, the plate member may extend only partially across the container top, e.g. from said edge to just beyond the central axis of the container.

Advantageously the valve means comprises a valve closure member in the form of a flexible diaphragm to engage a port of said fluid inlet (or outlet means). Alternatively the valve closure member may take the form of a part engageable pad.

By way of example, embodiments of this invention will now be described with reference to the accompanying drawing of which: Figure 1 is a longitudinal section through a first solenoid valve according to this invention; Figure 2 is a cross-sectional view along the line II-II of Fig 1 showing the components as being typically of circular form in plan view; and Figure 3 is a view similar to Fig 1 showing a second solenoid valve according to this invention.

The solenoid valve 15 illustrated in Figs 1 and 2 comprises a non-ferrous housing 1 provided at its lower end with lateral ports 2,3. Port 2 is an inlet for the fluid (liquid or gas) which is to be controlled. Port 3 is an outlet for the fluid. Port 2 is connected to a nozzle 4, which can be adjusted axially in the housing 1, typically by means of a screw thread 5.

A flexible diaphragm 6 is sealed to the housing 1 adjacent to the nozzle 4.

Another housing 7, made from a magnetically conducting material, is disposed within the housing 1. The outer wall of housing 7 is provided with one or more longitudinal slot-like voids 7a (see Fig 2). This housing 7 contains an electrical coil 8, comprising many turns of insulated fine wire, which is terminated outside the housing 1. A sleeve 9, made from a magnetically conducting material, is positioned within the coil 8. The sleeve 9 can be adjusted axially within the housing 7, typically by means of a screw thread 10 by means of which the sleeve 9 is attached to the housing 7.

A movable plate 11, made from a magnetically conducting material, pivots about an edge or peripheral point 12 of the plate upon an upper end of the housing 7, the pivotal movement being restricted by the housing 1. Accordingly, to maximise the plate's permissible movement, it extends only partially across the top of housing 7, e.g. of the order of the radial dimension of housing 7 so as to extend from the pivoting edge to just beyond the axis of housing 7.

A rod 13 made from a non-magnetic material extends longitudinally (e.g. axially) between plate 11 and the diaphragm 6. The length of this rod is such that the plate 11 is held tilted away from the upper surface of the housing 7.

The housing 7, the sleeve 9 and the plate 11 form a magnetic circuit such that, when a suitable electric current is applied to the terminals of the coil 8, the plate 11 is caused to move pivotally and/or axially towards the face of the housing 7. This movement causes the rod 13 to move axially and deflect the flexible diaphragm 6 into sealing engagement of the orifice in the nozzle 4, thereby to prevent fluid flow between the inlet port 2 and the outlet port 3. Removal of the electric supply to the coil 8 allows the pressure in the inlet port 2 to lift the diaphragm 6, the rod 13 and the plate 11 to their previous positions.

The magnetic attraction between plate 11 and sleeve 9 is enhanced by providing suitable voids (such as the slots 7a) in the outer wall of housing 7.

The solenoid valve 25 of Figure 3 is similar to the solenoid valve 15 of Figs 1 and 2, and like parts bear like reference numerals. However, the solenoid valve 25 has a valve closure member provided by a sealing pad 26 (instead of the diaphragm 6). Optionally, as shown in Fig 3, a low force spring 24 is provided to urge the valve closure member 26 away from its valve closing position - the force of spring 24 being in use overcome by the electromagnetically imparted closing force upon the valve closure member 26. A low force spring such as 24 may also be provided in the embodiment of Figs 1 and 2 to urge the diaphragm 6 away from its sealing engagement of the orifice in nozzle 4.

With each illustrated embodiment the adjustability of the nozzle 4 and the sleeve 9, as well as the space allowed for movement of the plate 11, permit these components to be set in position with considerable precision. Operation of the solenoid valve 15,25 can therefore be achieved by very small movements of the components 11,13 and 6, and the solenoid valve 15,25 can consequently operate with a very low electrical power input.

The positional setting of components 4 and 9 (and the space for the armature-like plate 11 permitted by the setting of sleeve 9) are usually made during manufacture of the device. However these positional settings can be adjusted during the service life of the solenoid valve 15,25 - if the operating parameters need to be altered - since these components are so readily accessible.

In a further modification of the embodiments of Figs 1 to 3, the diaphragm 6 (Fig 1) or by the pad 26 (Fig 3) is modified, e.g. by appropriate choice of materials, to provide a means of flow regulation through the nozzle orifice 4 (rather than the above-described ON/OFF-style of valve operation) thus controlling in a regulated way the pressure at port 2. To this end the diaphragm 6 and/or the pad 26 may be made of either flexible materials or a combination of flexible and rigid materials to provide optimum sealing pressure (when closed), flow control (when regulating flow), and appropriate wear characteristics.

The positional setting of components 4 and 9 (and the space for the armature-like plate 11 permitted by the setting of sleeve 9) are usually made during manufacture of the device. However these positional settings can be adjusted during the service life of the solenoid valve 15,25 - if the operating parameters need to be altered - since these components are so readily accessible.

Other modifications and embodiments - within the ambit and scope of the accompanying claims - will be readily apparent to those skilled in this art, and the invention is not to be deemed limited to the particular embodiment(s) and/or the modifications thereof hereinbefore described.

Claims (22)

1. A solenoid valve comprising first means to form a magnetic circuit having a gap therein, second means relatively movable with respect to said first means magnetically to close said gap, a solenoid winding to effect magnetisation of the first and/or the second means to produce said relative movement, and valve operating means responsive to said relative movement to operate the valve.

2. A solenoid valve according to Claim 1, wherein the first means comprises a double-walled chamber of magnetisable material containing said solenoid winding between its walls, said walls being interconnected at one end of the chamber.

3. A solenoid valve according to Claim 2, wherein at least one of the walls is discontinuous.

4. A solenoid valve according to Claim 2 or Claim 3, wherein the second means comprises a plate member of magnetisable material to overlie (and extend at least partially across) the other end of said chamber.

5. A solenoid valve according to Claim 4, wherein the plate member is pivoted by one edge upon said casing.

6. A solenoid valve according to any one of Claims 2 to 5, wherein the effective length of one of the walls of said double-walled chamber is adjustable to vary the chamber's magnetic effect upon the plate member.

7. A solenoid valve according to any one of Claims 2 to 5, wherein the effective length of one of the walls of said double-walled chamber is adjustable by screw-threaded means to vary the chamber's magnetic effect upon the plate member.

8. A solenoid valve according to any one of Claims 2 to 7 when dependant from Claim 4, wherein the valve operating means comprises an elongate operating member extending internally of the inner wall of the chamber beyond each of its said ends, one end of the operating member being engageable with part of the valve and the other end of the operating member being engageable by said plate member.

9. A solenoid valve according to Claim 8, wherein said part comprises a valve closure member engageable with a fluid inlet port and/or a fluid outlet port.

10. A solenoid valve according to Claim 9, wherein said valve closure member comprises a pad or a flexible diaphragm.

11. A solenoid valve according to Claim 9 or Claim 10, wherein the or each said port engageable by the valve closure member is provided by a unit positionally adjustable with respect to a housing for the solenoid valve.

12. A solenoid valve according to Claim 9 or Claim 10, wherein the or each said unit is positionally adjustable with respect to said housing for the solenoid valve by screw-threaded means.

13. A solenoid valve comprising: a housing of non-ferrous material, fluid inlet means to the housing, fluid outlet means from the housing, valve means to render said inlet means into and out of communication with said outlet means, a hollow container of magnetisable material within said housing, said container having an open top and containing a solenoid winding, an elongate valve operating member of non-ferrous material extending through the container, and a plate member of magnetisable material supported by the valve operating member to form a magnetic closure or "keeper" to the container's open top such that energising the solenoid magnetises the container and draws towards it said plate member to move said elongate valve operating member longitudinally such as to operate said valve means.

14. A solenoid valve according to Claim 13, wherein the fluid inlet means and/or outlet means controlled by said valve means is positionally adjustable with respect to said housing.

15. A solenoid valve according to Claim 13, wherein the fluid inlet means and/or outlet means controlled by said valve means is positionally adjustable with respect to said housing by screw-threaded means.

16. A solenoid valve according to any one of Claims 13 to 15, wherein the inner wall of said container is positionally adjustable, e.g. by screw-threaded means, with respect to the remainder of said container.

17. A solenoid valve according to any one of Claims 13 to 15, wherein the inner wall of said container is positionally adjustable with respect to the remainder of said container by screw-threaded means.

18. A solenoid valve according to any one of Claims 13 to 17, wherein said plate member is loosely mounted upon the valve operating member and has one edge resting upon an outer edge of said container to provide a pivot for the plate member.

19. A solenoid valve according to Claim 18, wherein the plate member extends only partially across the container top.

20. A solenoid valve according to Claim 18, wherein the plate member extends across the container top from said edge to just beyond the central axis of the container.

21. A solenoid according to any one of Claims 13 to 20 wherein the valve means comprises a valve closure member in the form of a flexible diaphragm to engage a port of said fluid inlet (or outlet) means.

22. A solenoid according to any one of Claims 13 to 20 wherein the valve means comprises a valve closure member in the form of a port engageable pad.