GB2449217A

GB2449217A - Magnetic flap valve

Info

Publication number: GB2449217A
Application number: GB0709505A
Authority: GB
Inventors: Christopher Terrell
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-05-18
Filing date: 2007-05-18
Publication date: 2008-11-19
Also published as: GB0709505D0

Abstract

A fast-acting magnetically coupled check valve for use in a shower comprises a magnet 202 rotatable by a motor 201 to repulse a magnetic flap valve 203 and thereby shut off flow of fluid through a conduit.

Description

Magnetic Safety Valve providing fast flow shut-off

Background of the Invention

A personal shower system whereby a required temperature of the output is maintained by thermostatic means is well known. A further refinement to this is the use of electronic means to control the temperature and flow; this is described in patents US2005 155656 and EPI 526312, and electronically controlled valves are commercially available.

Most designs of electronic valves use a motor to control the relative flows of hot and cold water. The valve may also use an electric motor, or a solenoid valve to shut the water off. In an electronic valve, it is desirable to have an alternative means of shutting off the flow of water in the event of a failure in the operation of the valve.

Most valves are also limited in how fast they can shut off the flow of water. In certain circumstances it may be desirable to have a response time that is much faster than can be achieved by using an electric motor or a mechanical thermostat to shut off the val e. For example, in the event of a failure of the cold supply water, even if the valve is operating IS correctly, it may not shut off the supply fast enough to prevent hot water from exiting the valve.

This invention provides for an additional, low cost valve that is only used where a rapid shut off of water is required that cannot be supplied by the main valve, or where the main valve has suffered from a failure of operation.

Detailed Description of the Invention

The invention consists of magnetically operated valve, which is attached at the outlet of another valve, which would typically be an electronic valve, though it may also be a traditional mechanical valve. Alternatively, the magjietically operated valve can be placed before the hot inlet, to shut off the how supply to the valve in the event of a failure, thereby rendering the valve safe.

Page 1 In normal operation (figure 1) the fluid is able to pass (101) without restriction through a lube (102). Within the tube is a chamber (103) that houses a magnetic flap valve (104). The flap valve is held in place against the side wall of the chamber by a second magnet (105) which is outside the chamber. At the point where the magnets are in close proximity, the chamber wall (106) is thitmer to enable magnetic forces to be transferred between the two magnets hut is of sufficient strength to contain the forces of water pressure within chamber (103). As the flap valve is held in place by the external magnet, the flow of fluid through the tube is not impeded.

The external magnet (105) is able to rotate. In normal operation the North/South Pole forces of the rotating magnet are positioned opposite to the South/North Poles of the flap magnet (104). Thus magnetic attraction holds the flap valve open allowing free flow of water through the tube.

Figure 2 shows how the valve achieves a rapid shut-off of the fluid flow. A motor (201) rotates the magnet (202) through one complete turn. During this rotation the flap valve (203) is moves by means of magnetic repulsion as the North/South Poles rotate in to a transitory situation whereby North Poles are opposite to North Poles and South Poles are opposite to South Poles. Thus the magnetic attraction has become repulsion on the flap valve. liiis repulsion force is at a maximum after a half turn of the rotating. The rotating magnet continues rotating for one complete turn (360 Degrees of movement). Whilst under the influence of these repulsive forces the flap has moved in to the water stream and becomes self-closing due to the water flow.

Since the magnetic forces obey an approximate inverse square law the magnetic opening and or closing forces on the gate are extremely weak once a gap has been created. In this situation of dynamic flow the gate movement is within the control of the fluid stream even though the rotating magnet has by now completed a full turn of 360 degrees.

Figure 3 shows the valve in the closed position. The water flow (301) has been stopped and this creates a pressure force against the flap valve (302). The flap valve is then pressed against a ridge (303) within the tube, forming a seal.

Page 2 In the present embodiment of the invention, the seal is nearly perfect but allows some fluid to escape under pressure. This leak is constructed by controlled flow channels in the scaling areas of the flap, or by a small hole in the flap thus allowing a leak to take place. When the supply of fluid to the flap valve ceases, then the slow leak of fluid rapidly reduces the pressure in the chamber (304) to ambient. Once this happens, the flap valve reverts to its open position. This is achieved either by the force of the magnet, or by the use of a weak spring, or by a combination of the two.

In the present embodiment of the invention a motor with appropriate gearing rotates the external magnet. However, the external magnet could equally consist of an electromagnet that reverses its polarity by reversing the cuffent flow in a coil, or by a soft magnetic material that is temporaijly turned into a magnet by the application of a current in a coil. Where a rotating motor is used, then the magnet is rotated through 360 degrees. This is controlled either by the use of a microswjtch or other sensor, or by controlling the length of the motor pulse.

In an alternative emlxxliment, the magnet (202) is rotated by approximately 180 degrees at is which point its rotation is physically stopped. This stoppage can be detected by measuring the motor current, or by asswning that the valve has come to a stop after a preset amount of' time.

The motor can then be reversed to reverse the position of the magnet, using the same method to fix its position.

The signal to close the flap valve is provided by a microprocessor and can be triggered by a number of preset events, including, but not limited to: the fluid temperature at some poilit in the system exceeding a preset amount; a report of valve failure from other electronic Systems within the main valve; the absence over a preset period of time of a status signal from other electronic systems within the main valve; or a user triggered command to divert the water flow or end the shower.

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Claims

Claims I. A rapid close off valve consisting of a magnetic flap valve

which in normal operation is held against the side of a chamber by a magnet outside the chamber, thereby allowing free flow of fluid; and where closing said flap valve is initiated by rotating the external magnetic field based on a preset input, and where closing said flap valve is completed by the flow of fluid though the valve, and where closure of said flap valve substantially seals off fluid flow.
2. A valve as claimed in claim 1 for use as a safety device in a personal shower to enable the hot water supply or the exit flow to be rapidly cut off in the event of an uncontrolled rise in output temperature.
3. A valve as claimed in any preceding claim that when used in conjunction with an electronic personal shower enables the flow of water to be cut off in event of a failure in the system either electronic or mechanical.
4. A valve as claimed in any preceding claim where closure is triggered by a signal from an onboard microprocessor
5. A valve as claimed in any preceding claim where closure is triggered by a signal from an external microprocessor, or by the absence of a signal which may indicate a failure of the external system.
6. A valve as claimed in any preceding claim that makes use of a magnetic coupling between the working environment of fluid flow and the outside world.
7. A valve as claimed in any preceding claim that uses the properties of magnetic coupling in both an attraction mode and a repulsion mode.
8. A valve as clainiecj in any proceeding claim that in shut-off position allows a slow leak of fluid so that the internal pressure is reduced to ambient once the supply of fluid is cut-off, and which then resets itself.

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9. A valve as claimed in any preceding claim maintains its shut-off position by making use of pressure differentials between the working environment and the outside world.
10. A valve as claimed in any preceding claim that makes use of material between the working environment and the outside world whereby the same material allows the passage of magnetic forces whilst acting as a barrier between the working environment and the outside world.

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