AU5406690A

AU5406690A - Valves

Info

Publication number: AU5406690A
Application number: AU54066/90A
Authority: AU
Inventors: John Keir Haffenden
Original assignee: DANSAM DEV Ltd
Current assignee: DANSAM HOLDINGS Ltd
Priority date: 1989-04-13
Filing date: 1990-04-12
Publication date: 1990-11-05
Also published as: WO1990012234A1

Description

VALVES TECHNICAL FIELD

This application relates to valves, and particularly, although not exclusively, to valves which are normally open but, in certain circumstances, are closed under the action of a resilient biassing force after release of a retaining element. BACKGROUND OF THE INVENTION AND PRIOR ART

GB-A-2179425 discloses a valve comprising an elongate displaceable element carrying a valve member for movement between open and closed positions, the displaceable element being resiliently biassed in one direction and being retained against displacement in that direction by a retaining element, the retaining element being operable to release the displaceable element for movement in the direction of resilient bias.

The retaining element is a plunger which engages a recess in the displaceable element, and is retractable by means of a solenoid, to release the displaceable element. The valve of GB-A-2179425 is used in domestic water systems. The valve is normally held open by the plunger. A flow sensor and a timing circuit are provided, and give a signal when flow through the valve has continued for more than a predetermined time. The signal causes the solenoid to be energized to withdraw the plunger, allowing the valve to close under the action of the resilient bias, so terminating the flow of water. Valves for such purposes are required to operate (i.e. close) reliably, even after remaining idle for a considerable period, which may amount to several years. A problem with the valve of GB-A-2179425 is that the plunger may sometimes stick, or jam in the recess in the displaceable element, and so will not be retracted when the solenoid is energized. Also, the plunger and the solenoid occupy a relatively large space, so that it is difficult to make the valve compact. DISCLOSURE OF INVENTION

According to the present invention the retaining element comprises an opening through which the displaceable element extends, the retaining element being tiltable between a retaining position, in which the opening is oblique with respect to the displacement direction of the displaceable element, and a release position, in which the opening is substantially aligned with the displacement direction of the displaceable element.

The retaining element may be operated by any appropriate means but, in a preferred embodiment, the retaining element is the armature of a solenoid which is tiltable relatively to a winding of the solenoid. Thus, the displaceable element will be retained when the winding of the solenoid is not energised, and will be released when the winding is energised. According to another aspect of the present invention, there is provided a solenoid comprising a winding and an armature which is mounted for pivotal movement relatively to the winding.

In a preferred embodiment, the armature is in the form of a plate, and the pivot axis of the armature is parallel to the plane of the plate. This pivot axis may also be parallel to a plane perpendicular to the winding axis.

Preferably, the armature is pivotably secured to a magnetic core body which supports the winding. For example, where the armature is a plate, the plate may be enclosed at one edge region between oppositely facing surfaces of the core body and a mounting block. These oppositely facing surfaces may be inclined to each other in order to provide abutments limiting the pivotal movement of the plate. For example, the abutment sur ace on the core body may be perpendicular to the winding axis, while the abutment surface on the mounting block may be inclined to that on the core body by an appropriate angle, such as 6^β or 8°. The armature plate may be secured to the core body by one or more fasteners passing through the mounting block and the plate into the core body.

The armature may be spring-loaded away from the winding, so that energisation of the winding causes the armature to be magnetically attracted against the spring loading.

The displaceable element and the valve member may be spring loaded towards the closed position. The retaining element then retains the displaceable element to hold the valve member in the open position until the winding is energised so that the armature releases the displaceable element, allowing the valve member to move to the closed position.

The winding may be controlled automatically so that the displaceable element is released under predetermined circumstances. For example, the displaceable element may be released after a predetermined time has elapsed from an initiating event. The initiating event may be the initial flow of water through a valve, so that the valve member will move to close the valve after water has flowed for a predetermined time. One use of such a valve is to prevent extensive flooding in industrial, commercial or domestic properties as a result of a burst pipe or other leakage. The predetermined time lapse will be set to exceed the maximum duration of flow under normal circumstances. However, if, for example, a pipe bursts, then the resulting continued flow through the valve will eventually cause the solenoid to be energised, so releasing the displaceable element to allow the valve member to move to the closed position. preventing further discharge of water.

Alternatively, the valve could be adapted for use, for example, in a sub-sea wellhead installation, for shutting off oil flow in an emergency. The valve may be actuated to close automatically or manually, and may be operable remotely from an oil rig or from the shore, perhaps via a radio link. BRIEF DESCRIPTION OF DRAWINGS

Figure 1 is a sectional view of an automatic shut- off valve;

Figure 2 is a side view of the valve of Figure 1; Figure 3 shows a solenoid used in the valve of Figures 1 and 2;

Figure 4 is a partially sectioned view, taken on the line IV-IV in Figure 3;

Figure 5 is a partially sectioned view, taken generally along the line V-V in Figure 3; and

Figure 6 shows another embodiment of a shut-off valve. HOPES FOR CARRYING OUT THE INVENTION

Referring first to Figures 1 and 2, the valve comprises an inlet spigot 2 and an outlet spigot 4, which communicate with each other past a valve seat 6. A valve member 8 is mounted in a housing 10 for movement between a closed position (represented by the lower half of the valve member 8 as shown in Figure 1) and an open position (represented by the upper half of the valve member 8) . The valve member 8 is carried by a displaceable element 12 in the form of a valve stem which is movable in a valve guide 14 accommodated in the housing 10. At its end away from the valve seat 6, the housing 10 is provided with a cap 16 having an aperture 18 through which the valve stem 12 projects. The valve stem 12 has an annular rib 20, and a spring 22 acts between the rib 20 and the cap 16 to bias the valve member 8 towards the seat 6. At the end away from the valve member 8, the valve stem 12 has a knob 24 for manual retraction of the valve member 8. The knob 24 is normally enclosed by a removable transparent cover 26. A rocker lever 28 is pivotally mounted in the valve guide 14 and projects inwardly of the housing 10 towards the valve stem 12. Outside the housing 10, the lever 28 is positioned to actuate an electrical switch 30. The region of the valve stem 12 which projects beyond the cap 16 extends through a solenoid 32. The solenoid is shown in greater detail in Figures 3 to 5, and comprises a core body 34 of magnetic material such as soft iron, and an armature 36, also of magnetic material. The solenoid is secured to the cap 16 by three screws 38 (only one of which is visible in Figure 1), which pass through holes 40 in the core body.

An annular winding 42, wound on a former 44, is situated within the core body 34. Electrical power can be supplied to the winding 40 through two leads 46.

The armature 36 is in the form of a plate which, as viewed in Figure 3, is approximately square but has cut-out regions 48 to provide access to the screws 38 in the holes 40. In the position shown in Figure 4, the armature 36 lies flat against an abutment surface 50 of the core body 34, which is perpendicular to the magnetic axis 52 of the winding 42. The armature 36 is retained on the core body 34 by two screws 54 which pass through a mounting block 56 and the armature 36 into the core body 34. The screws 54 pass through holes in the armature 36 with some clearance, to enable the armature 36 to pivot away from the core body 34, as shown in Figure 5. In this pivoted position, the armature contacts an abutment surface 58 of the mounting block 56, this abutment surface 58 being at an angle of 8° to the abutment surface 50 of the core body 34.

Two springs 60, accommodated in bores 62 in the core body 34, act against the armature 36 to bias it into the tilted position shown in Figure 5. 5 The armature 36 and the core 34 have aligned openings 64 and 66 respectively, through which the valve stem 12 passes, as shown in Figure 1.

A reed switch 68 is provided which is responsive to flow between the inlet and outlet spigots 2 and 4.

10 Control circuitry (not shown) is provided in the device for controlling the operation of the solenoid 32. The control circuitry receives signals from the reed switch 68 and incorporates a timer for purposes which will be discussed below. - 15 The device may be used for several different purposes, but one use is as a safety device to prevent extensive flooding in the event of a burst pipe or other major leakage in a domestic water system. For such a purpose, the device is installed in the primary

20 supply to the premises concerned, either where the mains supply enters the premises, or in the outlet of a main cold water storage tank. The control and operating circuitry is connected to an appropriate electrical supply such as the mains supply or a

25 battery. In normal use, the valve member 8 will be retracted from the seat 6 to allow water to flow through the device for consumption in the normal way. Thus, the valve stem 12 is retracted to the right (as shown for the upper half of the valve stem in Figure 1)

30 against the action of the spring 22. The valve stem 12 is retained in this position by the armature 36. Because the armature 36 is tilted, the opening 64 makes tight contact with the valve stem 12 to prevent it from moving to the left in Figure 1. By limiting the

35 maximum tilt angle of the armature 36, by appropriate positioning of the abutment surface 58, it is possible for the armature, in the tilted position, to engage the valve stem 12 tightly enough to retain it against the force of the spring 22, but sufficiently gently to permit manual closing of the valve by pushing the knob 24.

For much of the time, there will be no flow through the device because there will be no consumption of water in the premises. If, however, a bath is to be filled, the turning on of the bath taps will cause water to flow through the device, and this will trigger the reed switch 68, so that a signal will be applied to the control circuitry. The timer in the control circuitry will normally be set to provide a delay of, for example, fifteen minutes before the control circuitry causes energisation of the winding of the solenoid 32. If flow through the device stops before fifteen minutes have elapsed, the timer resets to zero. Thus, if filling of the bath takes, for example, ten minutes, the solenoid will not be actuated and the device will remain open.

However, should a water pipe downstream of the device burst, the flow of water through the device will be continuous. Once the flow has continued for the time delay set by the timer, the control circuitry will be actuated to energise the winding of the solenoid 32, and the armature 36 will be attracted magnetically towards the coil body 34. This will free the valve stem 12, and the valve will be moved to the closed position, against the seat 6, under the action of the spring 22. The flow of water from the burst pipe will then be stopped, and any resulting damage to the property will be mitigated.

To reset the device, the solenoid 32 is de- energised, allowing the armature 36 to return to its tilted position under the action of the springs, and the valve member 8 is manually retracted by pulling out the knob 24. The spindle 12 will automatically be retained in the withdrawn position by the armature 36.

The cover 26 encloses various indicating lights and control devices, as shown in Figure 2. Thus, there is an adjustment control 70 for adjusting the time delay between the beginning of flow through the device, as detected by the reed switch 68, and the energisation of the solenoid 32. There is also a push-button 72 for energising the solenoid 32 at any desired time in order to cause the valve to close. A further push button 74 is provided for overriding the timer in the event that continuous flow, for longer than the pre-set time, is required, for example if a hose pipe is to be used. Indicating lamps 76, 78 and 80 indicate, respectively, that the power is on, that the valve is open and that the override button 74 has been actuated. The lamp 78 is responsive to the switch 30. In the position shown in Figure 1, the switch 30 is open, and this will cause the control circuitry to illuminate the lamp 78. If the valve is closed, the upper half of the valve stem 12, as shown in Figure 1, is moved to the left and the rocker 28 will be engaged by the annular rib 20 to close the switch 30. This will extinguish the lamp 78. Another embodiment of shut-off valve is shown in Figure 6. This valve comprises an inlet 100 and an outlet 102, which communicate with each other past a valve seat 104. A valve member 106 is mounted in a housing 108 for movement between a closed position and an open position (as shown in the Figure). The valve member 106 is carried by a displaceable element 110 in the form of a valve stem which is movable in a valve guide 112 mounted within the housing 108 by means of screwthreads 109. At its end away from the valve seat 104 the valve stem 110 has a reduced diameter portion 114 which projects through an aperture 116 in a cap 118 which is mounted on the valve guide 112. A spring 120 acts between the cap 118 and the radial surface 122 of the valve stem 110 to bias the valve member 106 towards the seat 104.

The region of the valve stem 110 which projects beyond the cap 118 extends through a solenoid 124 which is constructed in a similar manner to that shown in Figure 1. The solenoid 124 is supported a short distance from the cap 118, and comprises a core body 128 and an armature 130. The armature 130 is retained between the core body 128 and the cap 118 by a mounting block 133 and guide members 132 (only one of which is visible in Figure 6) which pass through the armature 130 with some clearance, to enable the armature 130 to pivot away from the core body 128, as shown in Figure 3. The armature 130 and the core body 128 have aligned openings 134 and 136 respectively, through which the valve stem 110 passes. Electrical power can be supplied to an annular winding situated within the core body 128 by means of wires 138 which communicate with a power source. The wires pass through an aperture 140 in a cover 142 which is mounted on the housing 108 and encloses the valve member 106. Sealing means 144 and 146 are provided respectively between the wires 138 and the cover 142 and also between the cover 142 and the housing 108 (where they take the form of an O-ring seal) to seal the valve from the outside environment. O-ring seals 148, 150 and 152, between the housing 108 and the valve guide 112, and O-ring seals 154 and 156, between the guide member 112 and the valve stem 110, are provided to seal the valve actuating mechanism from the flow. Projections 158 abut the valve member 106 in the open position in order to hold it away from the lower face of the valve guide 112 to avoid operating delays owing to suction effects when the valve stem 110 is released.

The valve shown in Figure 6 is particularly suitable for use in a hostile environment. For example, it may be installed in an underwater oil pipeline, close to a wellhead, so as to serve as a blow out prevention valve. In normal use, the valve member 106 will be retracted from the seat 104 to allow oil to flow through the device. Thus, the valve stem 110 is retracted upwards against the action of the spring 120. The valve stem 110 is retained in this position by the armature 130. Because the armature 130 is tilted, the opening 136 makes tight contact with the valve stem 110 to prevent it from moving downwards in the Figure. In an emergency, for example, power is supplied to the winding of the solenoid 124, and the armature 130 will be attracted magnetically towards the core body 128. This will free the valve stem 110, and the valve will move to the closed position, against the seat 104, under the action of the spring 120. The flow of oil will then be stopped.

The solenoid requires only a low voltage supply (such as 12 volts) to operate. Operation of the solenoid may be effected by means of a radio link or other remote actuation device, or by a diver.

To reset the device, the solenoid 124 is de- energised, allowing the armature 130 to return to its tilted position, and the oil pressure across the valve member 106 is equalized. The valve member 106 will than be retracted by the oil pressure as a result of the difference in exposed area on the two sides of the valve member 106. The valve stem 110 will automatically be retained in the withdrawn position by the armature 130-

It will be appreciated that the solenoid shown in Figures 3 to 5 has uses other than those described above.

Claims

1. A valve comprising an elongate displaceable element (12, 114) carrying a valve member (8, 106) for movement between open and closed positions, the displaceable element (12, 114) being resiliently biassed in one direction and being retained against displacement in that direction by a retaining element (36, 130), the retaining element (36, 130) being operable to release the displaceable element (12, 114) for movement in the direction of resilient bias, characterized in that the retaining element (36, 130) has an opening (64, 134) through which the displaceable element (12, 114) extends, the retaining element (36, 130) being tiltable between a retaining position, in which the opening (64,134) is oblique with respect to the displacement direction of the displaceable element (12, 114) and a release position, in which the opening (64, 134) is substantially aligned with the displacement direction of the displaceable element (12, 114).

2. A valve as claimed in claim 1, characterized in that the retaining element (36, 130) is the armature of a solenoid (32, 124).

3. A valve as claimed in claim 2, characterized in that the retaining element (36, 130) comprises a plate which is tiltable relatively to a winding (42) of the solenoid (32, 124) about an axis which is parallel to the plane of the plate (36, 130).

4. A valve as claimed in claim 3, characterized in that the plate (36, 130) is disposed at one edge region between oppositely disposed surfaces of the solenoid (32, 124) to limit pivotal movement of the plate (36, 130).

5. A valve as claimed in any one of claims 2 to 4, characterized in that the armature (36, 130) is spring-loaded towards the tilted position.

6. A valve as claimed in any one of the preceding claims, characterized in that the displaceable element (12, 114) is resiliently biassed towards the closed position of the valve.

7. A valve as claimed in any one of the preceding claims, characterized in that a flow sensor (68) is provided which is responsive to flow through the valve, timer circuitry being provided which receives input from the flow sensor, the circuitry being adapted to cause closure of the valve after a predetermined period of continuous flow through the valve.

8. A solenoid comprising an armature (36) and a winding (42), characterized in that the armature is pivotable relatively to the winding.

9. A solenoid as claimed in claim 8, characterized in that the armature (36) and the winding (42) are provided with aligned openings (64, 66).

10. A solenoid as claimed in claim 8 or 9, characterized in that the armature (36) comprises a plate, which is pivotable relatively to the winding (42) about an axis which extends parallel to the plate.