GB2290467A - Temperature-sensitive drain plug - Google Patents

Abstract

A drain plug (10) comprises a body to seal an outlet in said container, the body or at least a part thereof being releasably from said outlet when the temperature of a fluid in the container exceeds a predetermined temperature allowing fluid to flow through the outlet. The plug (10) can be mounted on a bimetallic support (12) which expands to release the plug from a water outlet if the safe temperature is exceeded. Alternatively a shape-memory effect material can be used for the support (12), the change in state of such member on the safe temperature being exceeded being utilised to release the plug. <IMAGE>

Description

A PLUG This invention relates to a plug for sealing an outlet in a fluid container and more particularly for sealing an outlet in a bath or sink.

It is common when baths or sinks are filled with water for a mixture of both hot and cold water to be introduced into the bath in an attempt to achieve a bath having water of a desired temperature. This usually involves trial and error in the setting of the hot and cold water taps respectively, or alternatively the mixer tap, to achieve a bath or sink having the water of the required temperature.

Consequently, accidents can happen in which persons step into or place their hands and/or arms and/or legs into water in a bath or sink which is too hot and therefore they can be burnt or scalded. This problem is particularly acute in the case of young children, the elderly, infirm or disabled.

It is an object of the present invention to provide a plug which can automatically release fluid from the outlet of a fluid container when the temperature of fluid exceeds a particular value.

According to the present invention therefore there is provided a plug for sealing an outlet in a fluid container, said plug comprising a body to seal said outlet, said body, or at least a part thereof, being releasable from said outlet when the temperature of a fluid in the container exceeds a predetermined temperature allowing fluid to flow through the outlet.

With this arrangement it is possible to allow a fluid container to empty, or at the very least provide an indication that the temperature of the fluid is too hot, when the temperature of the fluid exceeds a predetermined temperature. In this way the occurrence of accidents of the type mentioned above can be minimised.

Preferably said plug body is formed from a resilient material and more particularly may be formed from a rubber material. Preferably said plug body is of conventional shape, having a dome shaped top surface and substantially inwardly inclined side walls.

Preferably one end of a support member is connected to said plug body and another end connected to an outlet of said container such that the body is mounted for movement relative to said outlet. Said one end of said support may be embedded in said plug body during moulding of the body by extrusion or otherwise.

Said support member may be formed from a thermally expandable material, and it is felt that use of a bimetal strip is particularly suited to the present application. However, the support member can be formed from any suitable thermally expandable material. Alternatively, the support member may comprise a shape-memory effect material which changes state when a predetermined safe temperature is exceeded. In these cases the support member may act directly on said body to release the body away from the outlet as it expands linearly or changes state. Alternatively a heat sensor or any other suitable means may be provided which senses the water temperature and causes the body, or part thereof, to be released from the outlet when the temperature sensed exceeds a predetermined temperature.

A resilient biassing means may be provided which, on release of the body, or part thereof, from the outlet when an excessive temperature is sensed, biasses the plug body, or part thereof, away from the outlet.

If desired, a catch mechanism can be provided which normally holds said plug body, or part thereof, in said outlet, said catch being releasable upon sensing of a temperature above said predetermined temperature to cause release of said body, or part thereof, from the outlet. In these circumstances, upon release of the catch mechanism, the plug, or part thereof, may be moved upwardly away from the outlet under the action of the spring on the support member.

As an alternative to the above, in the case where the plug is connected to the fluid container by a chain or similar, said support member may be arranged to act on the chain either directly, or indirectly, via an operative link to release the body, or part thereof.

Furthermore, it may be possible to form substantially the whole plug from a thermochromic material, or alternatively only a part of the body can be formed from a thermochromic material, in either case wherein a visual indication of temperature can be provided.

The plug of the present invention can be mounted on a plug member, one end of which is linked to the outlet and the other end of which is linked to the body, the plug being movable between a lowered position in which the outlet is sealed and a raised position in which the outlet is open and fluid can flow through the outlet by operation of a lever or other control member linked to the plug member or plug via an operative connection.

It is thought that the present invention will find particular application in the context of fluid containers such as baths or sinks, however the invention can be used in any fluid container in which excessive temperature is desired to be avoided.

The invention will now be described further by way of example only and with reference to the accompanying drawings of which: Fig. 1 shows a diagrammatic representation of one form of plug according to the present invention in a closed position; and Fig. 2 shows the plug of Fig. 1 in an open position; Fig. 3 shows a diagrammatic representation of a second form of plug according to the present invention in a closed position; Fig. 4 shows the plug of Fig. 3 in an open position; and Fig. 5 shows a plan view of the plug of Figs. 3 and 4.

Referring now to the drawings, there is shown in Fig. 1 a plug for a bath or sink outlet.

The plug 10 comprises a moulded rubber body 11 which has formed integrally with, so as to depend downwardly therefrom, a support member 12. The support member 12 can be formed integrally with the plug body 11 by embedding one end thereof in the body 11 during moulding.

The support member 12 comprises, in one embodiment, a bimetal strip, the constituent metals being chosen dependent upon the predetermined temperature required to be reached before the plug body 11 is moved away from the waste to allow the water to flow out of the bath or sink, e.g. aluminium has a coefficient of linear expansion of 25 x 106/"C, whilst nickel has a coefficient of 13 x 106/"C. Thus by appropriate choice of the constituent metals, the support member 12 can be arranged to move the plug body 11 away from the waste outlet at any predetermined temperature. Alternatively the support member 12 can be formed from a shape-memory effect material which is arranged to change state when a predetermined safe temperature is exceeded and this change of state can be utilised to move the plug body 11 away from the waste outlet.

Movement of the plug body 11 when the support member 12 expands, or the shape-memory effect material changes state, is biassed by a bias spring 13 which acts to control movement of the plug body 11 under the action of the expanding support member 12.

If desired, although not shown in the drawings, the support member 1 2 may include a catch mechanism which normally retains the plug in the outlet against the bias of the spring 13. When the support member 12 expands, it releases the catch mechanism, allowing the plug body 11 to move away from the outlet under the action of the spring 13, the extent of movement being limited by the support member 12.

Thus it can be seen that the plug of the present invention allows the release of water from a bath or sink automatically if the water exceeds a predetermined temperature which causes expansion of the support member to allow the plug body 11 to move clear of the outlet, whereby water can flow out of the bath or sink, as shown in Fig. 2.

An alternative embodiment of plug is shown in Figs. 3 to 5 of the drawings. In this embodiment a heat sensor 14 is mounted on an upper surface of the plug body 11 (see Fig. 5) adjacent the support member 12.

In this embodiment a catch mechanism (not shown) is provided which normally retains the body 11 in the outlet. When the temperature of the water sensed by the heat sensor 14 is greater than a predetermined temperature, the heat sensor causes release of the catch mechanism, the plug body 11 moves away from the outlet under the action of the spring 13 as in the previous embodiment, to allow water to drain out of the bath or sink.

Of course, it will be appreciated that the heat sensor 14 can comprise any suitable temperature sensing device of mechanised or electronic form.

If necessary the sensor can be connected to the catch mechanism via an intermediate operative link of any suitable form.

Furthermore it will also be appreciated that in the case of either embodiment, the plug is entirely re-usable.

Whilst in the above embodiments the plug body 11 as a whole is described as being movable away from the waste outlet once a predetermined safe temperature has been exceeded, it is equally possible for only a part of the body 11, for example a seal for a fluid outlet bore in the body 11, to be moved away to allow fluid to flow out.

Furthermore, instead of the support member acting on the plug directly, it can be arranged to act on a chain which links the plug to the container, whereby when a predetermined safe temperature is exceeded the plug can be pulled out of the waste outlet. The support member can act directly on the chain or via an intermediate operative connection.

Also it is possible to form a whole or a part of the plug body 11 from a thermochromic material whereby a visual indication of temperature of fluid in the container can be given.

It is of course to be understood that the invention is not intended to be restricted to the details of the specific embodiments which are described by way of example only.

Claims (17)

1. A plug for sealing an outlet in a fluid container, said plug comprising a body to seal said outlet, said body, or at least a part thereof, being releasable from said outlet when the temperature of a fluid in the container exceeds a predetermined temperature allowing fluid to flow through the outlet.

2. A plug according to claim 1 wherein the plug body is formed from a resilient material, preferably rubber.

3. A plug according to claim 1 or claim 2 wherein the plug body has a dome shaped top surface and substantially inwardly inclined side walls.

4. A plug according to any one of claims 1 to 3 wherein one end of a support member is connected to said plug body and another end connected to an outlet of said container such that the body is mounted for movement relative to said outlet.

5. A plug according to claim 4 wherein one end of said support is embedded in said plug body during moulding of the body.

6. A plug according to claim 4 or claim 5 wherein said support member is formed from a thermally expandable material.

7. A plug according to claim 4 wherein said support member comprises a bimetal strip.

8. A plug according to claim 4 or claim 5 wherein said support member is formed from a shape-memory effect material which changes state when a predetermined safe temperature is exceeded.

9. A plug according to any one of claims 1 to 8 wherein a heat sensor is provided on the plug, which sensor detects the water temperature and causes the body, or part thereof, to be released from the outlet when the temperature sensed exceeds a predetermined temperature.

10. A plug according to any one of claims 1 to 9 wherein a resilient biassing means is provided which upon release of the body, or part thereof, from the outlet when an excessive temperature is sensed, biasses the plug body, or part thereof, away from the outlet.

11. A plug according to any one of claims 1 to 10 wherein a catch mechanism is provided which normally holds said plug body, or part thereof, in said outlet, said catch being releasable upon sensing of a temperature above said predetermined temperature to cause release of said body, or part thereof, from the outlet.

12. A plug according to claim 11 when dependant on claim 10 wherein upon release of the catch mechanism, the plug, or part thereof, may be moved upwardly away from the outlet under the action of the spring on the support member.

13. A plug according to any one of claims 4 to 12 wherein the plug is connected to the fluid container by a chain and said support member is arranged to act on the chain either directly, or indirectly, via an operative link, to remove the body, or part thereof.

1 4. A plug according to any one of claims 1 to 1 3 wherein substantially a whole of the body of the plug is formed from a thermochromic material wherein a visual indication of temperature can be provided.

15. A plug according to any one of claims 1 to 13 wherein at least a part of the body is formed from a thermochromic material wherein a visual indication of temperature can be provided.

16. A plug substantially as hereinbefore described with reference to Figures 1 and 2 or 3, 4 and 5.

17. A bath or sink including a plug according to claim 1.