GB2376733A

GB2376733A - Anti-scald safety valve for a shower

Info

Publication number: GB2376733A
Application number: GB0104252A
Authority: GB
Inventors: Christopher Terrell
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-02-21
Filing date: 2001-02-21
Publication date: 2002-12-24
Also published as: GB0104252D0

Abstract

A safety valve for a shower having obstructing means to prevent water flow and restraining means to hold the valve in an open position wherein the restraining means is deactivated in response to a significant rise in water temperature. The obstructing means may be a pivoted flap or a ball. The restraining means may restrain the obstructing means by magnetic force. The obstructing means may obstruct the flow in response to flow pressure, or gravity. The safety device enables hot water to be rapidly cut off in the event of an uncontrolled rise in output temperature.

Description

Safety Device for Personal Shower

Th A Fast Response Magnetically Coupled Stop Valve, generally for use in a personal shower system whereby the operation of the same said stop valve is actuated by electricity and where the operation of the valve is essentially self closing.

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, as for instance described in UK Patent 2 341 792.

In British Patent publication 2 341 792, a device for controlling the input water flow proportions of hot and cold water is shown. The device controls water by the use of gate valves or butterfly valves which are moved by means of an electric motor and gearbox. This movement of the valves controls the temperature at the output and the response time of this operation is related to the speed at which the gate valves can operate.

In certain circumstances it is desirable to have a response time, which is much faster than described above. A particular circumstance of this is for institutional use where concerns of elderly persons is of paramount importance.

For instance a circumstance can occur in a situation where the cold SY water supply to a working shower is removed by the drainage of a nearby toilet or by maintenance damage to the cold water suppiy. in certain cases hot water of boiling temperature can enter the showering environment as part of a boiler failure scenario.

Under these circumstances the electronic sensor senses a rapid gain in output temperature and the gate valves (or butterfly valves) adjust to correct this. However, there is a few seconds delay before the gate valves can adjust fully to correct this abnormality and this invention relates to a means whereby an Enhanced Response to this situation can be achieved.

The invention will now be described by way of example only with reference to the accompanying drawings.

Figure 1 illustrates the method whereby a personal shower system is operated using electronic control. Flow is initially set by means of a mechanically operated flow valve which in the off position fully seals the incoming hot and cold delivery pipes so no flow is taking place. Also illustrated is a flap valve (detailed in Fig. 2), which is contained within the working environment of the valve and separated from the outside world by a thinning of the separating material. This thinning enables magnetic

forces to be transferred between the outside world and the working environment but is of sufficient strength to contain the forces of pressure within the aforesaid operating environment.

When the shower is operated on start up, a flap valve, which is made of magnetic material and loosely hinged, is held in the open flow position by the poles of a rotating magnet. This is achieved by having the North/South Pole forces of the rotating magnet opposite to the South/North Poles of the flap magnet. Thus magnetic attraction holds the flap valve open allowing free flow of water through the pipes (Fig. 2 A).

In a situation whereby a rapid and dangerous rise in temperature is detected by the electronics monitoring the output temperature then a digital signal is applied to the motor (Fig. 1 A). This rotates the magnet (Fig. 2 B), through one complete turn. During this rotation the flap valve 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. This repulsion force is at a maximum after a half turn of the rotating magnet.

The rotating magnet continues rotation 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 water flow. The angular velocity of closing being determined by the flow velocity of hot water (Fig. 2 B). Since the magnetic forces obey an approximate inverse square law the magnetic opening and or closing forces on the gate are extremeiy weak once a gap has been created. In this situation of dynamic flow the gate movement is within the control of the water stream even though the rotating magnet has by now completed a full turn of 360 degrees.

Thus the hot water supply to the valve is instantly stopped with the seal being nearly perfect (Fig. 2 C). This achieves safety from scalding or over-temperature dangers. Subsequent to this, a reset can be achieved by turning off the valve. Within this off situation, the differential pressures on the flap valve is now zero due to the perfect seal on the mechanical disks and the near perfect seal of the flap. It is this near perfect seal that allows water seepage to fully equalise all water forces on the flap after a reasonable time lapse.

The flap valve then returns under the forces of gravity or by spring forces (not illustrated) to within the pull domain of the rotating magnet.

This magnet is now in a position of pulling the flap valve in to the position whereby it is held by the magnetic attraction, as described.

As an alternative to the Flap Valve, but using the same principle, a Ball Valve can be introduced into the personal shower system (Fig. 4 A).

The ball valve still incorporates an external magnet that rotates through 360 degrees and an internal magnet that cannot rotate but can slide in a linear motion contained by runners within the valve body.

The internal magnet is again retained by the external magnet (Fig. 3 A) until it rotates 180 degrees, thus repelling the internal magnet and causing it to slide up the runners. This internal magnet pushes a ball into the fluid flow (Fig. 3 B). The velocity of the fluid flow forces the ball into the opening of the exit pipe, thus achieving a near complete seal preventing the fluid flow (Fig. 3C).

The internal magnet returns to its initial position as the external magnet rotates the full 360 degrees. The ball is released once the personal shower valve is shut off due to the partial pressures equalising either side of the ball. Upon release, the ball is guided back into its holder by means of gravity and a guide.

A significant advantage of using a magnetic coupling is that it avoids problems due to the accumulation of limescale and solid contaminants.

Claims

Claims. yt..

1. A safety device used in a personal shower to enable the hot water to be rapidly cut off in the event of an uncontroiied rise in output temperature.

2. The same device is actuated by electrical means.

3. The same device makes use of magnetic coupling between the working environment of water flow and the outside world.

4. The same device uses the properties of magnetic coupling in both an attraction mode and a repulsion mode.

5. The same device maintains shut off in safety mode by making use of pressure differentials between the working environment and the outside world.

6. The same device 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.

7. A safety device used in a personal shower, comprising a valve chamber; a water inlet for supplying water to said chamber; a water outlet for receiving water from said chamber; valve obstructing means configured to prevent the flow of water through said chamber; restraining means configured to restrain said obstructing means; and deactivating means configured to de-activate said restraining means in response to detecting a significant rise in water temperature.

8. A device according to claim 7, wherein said valve obstructing means is a pivoted flap.

9. A device according to claim 7, wherein said valve obstructing means is a ball.

10. A device according to claim 7, wherein said restraining means is configured to restrain said obstructing means by magnetic force.

11. A device according to claim 7, wherein said obstructing means obstructs said flow in response to flow pressure.

12. A device according to claim 7, wherein said obstructing means obstructs said flow in response to gravity.