GB1573205A

GB1573205A - Temperature responsive valve

Info

Publication number: GB1573205A
Application number: GB513279A
Authority: GB
Original assignee: Delta Materials Research Ltd
Current assignee: Delta Materials Research Ltd
Priority date: 1977-05-10
Filing date: 1977-05-10
Publication date: 1980-08-20

Description

(54) TEMPERATURE-RESPONSIVE VALVE (71) We, DELTA MATERIALS RESEARCH LIMITED, a British Company of P.O. Box 22. Hadleigh Road, Ipswich, Suffolk IP2 OEG. do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement:- This invention relates to temperatureresponsive valve capable of controlling the flow of a fluid through a passage or duct according to the temperature of the fluid.

Known temperature responsive valves have temperature detectors which operate valve members according to the detected temperature. The detector may incorporate a liquid which effects the required operating action by expansion. a solid which in changing state to a liquid expands or contracts, or a bimetallic element. It has further been proposed in U.S. Patent Specification No. 3 664 582 and in U.K. Patent Specification No. 1 308 107 to use as the temperature detector an element made of a nickel titanium alloy and having a temperature actuated shape memory.

As will be perceived from a consideration of the above numbered patents temperature-responsive valves as known previously are relatively complicated and bulky and do not lend themselves easily to applications where available space is limited. The designs of valve actuator using shape memory alloys as described in those patents are particularly inappropriate for use in thermostatic valves for cooling systems, for example.

A temperature-responsive valve according to the present invention comprises a valve member mounted in a passage to control the flow of fluid through that passage, the valve member comprising a helically wound spring made of a shape memory effect material; and having a plurality of turns the spacing of which varies with temperature whereby the flow of fluid between the turns is controlled.

As is known, a shape memory effect material has a transition temperature range and over which the elastic modulus of the material varies significantly with temperature in a reversible manner which is dependent on the composition of the material. The composition of the material is so chosen that the valve opens and closes at required temperatures.

The invention will be more readily understood by way of example from the following description of a temperature responsive valve in accordance therewith, reference being made to the accompanying drawing, which shows the valve member in perspective in a passage which is partly cut away.

In the figure, a passage through which fluid can flow is shown at 12, a valve member at 13 and a biasing spring at 14.

The valve member 13 is a helically wound spring with a plurality of turns and consists of an appropriately wound strip of shape memory effect alloy. The outer turn of the valve member is sealed to the wall of the passage so that, when the valve member is axially compressed to bring the turns into contact with one another, the valve member closes the passage.

Bias spring 14, which is also secured in the wall of the passage 12 applies an axial force to the valve member 13 in a direction tending to compress the latter into the shut condition. At low temperature of the fluid, valve member 13 has low stiffness and is compressed by bias spring 14 to shut the valve. As the temperature rises, valve member 13 expands to the position shown and the fluid is allowed to pass through the spacings between its turns.

WHAT WE CLAIM IS: 1. A temperature-responsive valve comprising a valve member mounted in a passage to control the flow of fluid through

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. (54) TEMPERATURE-RESPONSIVE VALVE (71) We, DELTA MATERIALS RESEARCH LIMITED, a British Company of P.O. Box 22. Hadleigh Road, Ipswich, Suffolk IP2 OEG. do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement:- This invention relates to temperatureresponsive valve capable of controlling the flow of a fluid through a passage or duct according to the temperature of the fluid. Known temperature responsive valves have temperature detectors which operate valve members according to the detected temperature. The detector may incorporate a liquid which effects the required operating action by expansion. a solid which in changing state to a liquid expands or contracts, or a bimetallic element. It has further been proposed in U.S. Patent Specification No. 3 664 582 and in U.K. Patent Specification No. 1 308 107 to use as the temperature detector an element made of a nickel titanium alloy and having a temperature actuated shape memory. As will be perceived from a consideration of the above numbered patents temperature-responsive valves as known previously are relatively complicated and bulky and do not lend themselves easily to applications where available space is limited. The designs of valve actuator using shape memory alloys as described in those patents are particularly inappropriate for use in thermostatic valves for cooling systems, for example. A temperature-responsive valve according to the present invention comprises a valve member mounted in a passage to control the flow of fluid through that passage, the valve member comprising a helically wound spring made of a shape memory effect material; and having a plurality of turns the spacing of which varies with temperature whereby the flow of fluid between the turns is controlled. As is known, a shape memory effect material has a transition temperature range and over which the elastic modulus of the material varies significantly with temperature in a reversible manner which is dependent on the composition of the material. The composition of the material is so chosen that the valve opens and closes at required temperatures. The invention will be more readily understood by way of example from the following description of a temperature responsive valve in accordance therewith, reference being made to the accompanying drawing, which shows the valve member in perspective in a passage which is partly cut away. In the figure, a passage through which fluid can flow is shown at 12, a valve member at 13 and a biasing spring at 14. The valve member 13 is a helically wound spring with a plurality of turns and consists of an appropriately wound strip of shape memory effect alloy. The outer turn of the valve member is sealed to the wall of the passage so that, when the valve member is axially compressed to bring the turns into contact with one another, the valve member closes the passage. Bias spring 14, which is also secured in the wall of the passage 12 applies an axial force to the valve member 13 in a direction tending to compress the latter into the shut condition. At low temperature of the fluid, valve member 13 has low stiffness and is compressed by bias spring 14 to shut the valve. As the temperature rises, valve member 13 expands to the position shown and the fluid is allowed to pass through the spacings between its turns. WHAT WE CLAIM IS:

1. A temperature-responsive valve comprising a valve member mounted in a passage to control the flow of fluid through that passage, the valve member comprising a helically wound spring made of a shape memory effect material and having a plurality of turns, the spacing of which varies with temperature whereby the flow of fluid between the turns is controlled.

2. A temperature-responsive valve as claimed in claim 1 in which the turns are in engagement with one another at one temperature and open to allow flow of fluid therethrough as the temperature changes from that temperature.

3. A temperature-responsive valve as claimed in claim 1 or claim 2, including resilient means biasing the spring made of shape memory effect material.

4. A temperature-responsive valve as claimed in claim 3, in which the resilient means biases the helically wound spring towards a shut position in which the turns are in engagement.

5. A temperature-responsive valve as claimed in any one of the preceding claims.

in which the spring is wound as a conical or frusto-conical helix.