US 4,281,708 A · Automatic thermal switch

Abstract

An automatic thermal switch to control heat flow includes a first thermally conductive plate, a second thermally conductive plate and a thermal transfer plate pivotally mounted between the first and second plates. A phase-change power unit, including a plunger connected to the transfer plate, is in thermal contact with the first thermally conductive plate. A biasing element, connected to the transfer plate, biases the transfer plate in a predetermined position with respect to the first and second plates. When the phase-change power unit is actuated by an increase in heat transmitted through the first plate, the plunger extends and pivots the transfer plate to vary the thermal conduction between the first and second plates through the transfer plate. The biasing element, transfer plate and piston can be arranged to provide either a normally closed or normally open thermally conductive path between the first and second plates.

Claims18

Dependent claims

A thermal switch for selectively varying the heat transferred between an uncontrolled variable temperature environment and a controlled temperature environment comprising:

first and second spaced members, respectively having surfaces exposed to said uncontrolled and controlled environments, said members having high thermal conductivities relative to said uncontrolled and controlled environments;
a heat motor being in heat exchange relationship with said first spaced member;
and
pivotal armature means between said first and second spaced members, said armature means having a relatively high thermal conductivity and having one end thereof coupled to said heat motor, said armature means being responsive to said heat motor so that said armature means is pivoted between first and second positions in response to the amount of heat absorbed by said heat motor from said first spaced member, said armature means being in contact with said first and second spaced members in said first position to provide a high thermal conductivity path between said first and second spaced members, and said armature means being spaced from said first and second spaced members in said second position to provide a substantially low thermal conductivity path between said first and second spaced members.

1 more element

A thermal switch for selectively varying the heat transferred between an uncontrolled variable temperature environment and a controlled temperature environment comprising:

first and second thermally conductive spaced members, respectively having surfaces exposed to said uncontrolled and controlled environments, said first and second thermally conductive spaced members having high thermal conductivities relative to said uncontrolled and controlled environments;
a thermally conductive armature disposed between said first and second thermally conductive spaced members;
means for biasing said thermally conductive armature in a predetermined position with respect to said first and second thermally conductive spaced members;
and
means, in a heat exchange relationship with said first thermally conductive spaced member and coupled to said thermally conductive armature, for driving said thermally conductive armature is response to a detected temperature change in said first thermally conductive spaced member so as to vary the thermal conduction between said first and second thermally conductive spaced members through said thermally conductive armature.

2 more elements

A thermal switch for selectively varying the heat transferred between an uncontrolled variable temperature environment and a controlled temperature environment comprising:

first and second thermally conductive spaced plates, respectively having surfaces exposed to said uncontrolled and controlled environments, said first and second thermally conductive spaced plates having high thermal conductivities relative to said uncontrolled and controlled environments;
a support disposed between said first and second thermally conductive spaced plates, said support being mounted to said second thermally conductive spaced plate;
a thermally conductive transfer plate pivotally mounted to said support;
spring means for biasing said thermally conductive transfer plate in a predetermined position with respect to said first and second thermally conductive spaced plates;
and
a phase-change power unit having a first portion in a heat exchange relationship with said first thermally conductive spaced plate and a second portion coupled to said thermally conductive transfer plate, said phase-change power unit driving said thermally conductive transfer plate in response to a detected temperature rise in said first thermally conductive spaced plate so as to vary the thermal conduction between said first and second thermally conductive spaced plates through said thermally conductive transfer plate.

3 more elements

Dependencies are inferred from the claim text.

Automatic thermal switch

Life of this patent

Automatic thermal switch

Life of this patent

Abstract

Claims18