Thermal switch assembly and system

Claim 2

A thermal switch assembly comprising thermally actuated switch means including heat responsive means and a switch of the normally closed type which is adapted to be opened in response to a rise in temperature of said heat responsive means, heating means within heat affecting range of said heat responsive means and adapted, in an atmospheric environment, of increasing the temperature of said heat responsive means sufficiently to open said switch and maintain it in its open condition during prevalence of such atmospheric environment, and adapted to close said switch from an open condition thereof when said heating means is exposed to a change in environment having heat conductively exceeding that of said atmospheric environment, sufficient to cool said heat responsive means below the switch opening temperature of said heat responsive means, and means, in response to such closing of said switch, for increasing the capacity of said heating means to a point still below the switch opening temperature of said heat responsive means while said heating means of increased capacity is exposed to such changed environment, whereby upon subsequently removing such changed environment and exposing said heating means of increased capacity to said initial atmospheric environment, said heating means of increased capacity will more rapidly restore said switch to its open condition.

Claim 3

A thermal switch assembly in accordance with claim 1, characterized by said switch means including a normally closed microswitch and said heating means including an electrical resistance element and a housing therefor of heat conductive material.

Claim 4

A thermal switch assembly in accordance with claim 2 characterized by said means for increasing the capacity of said heating means including a paralleling electrical resistance element connectable in circuit by said microswitch when said microswitch is in its closed condition.

Claim 5

A thermal liquid level control system comprising a pump having an electrical motor drive coupled thereto; a thermal switch assembly including thermally actuated switch means involving heat responsive means and a normally closed switch adapted to be opened in response to a rise in temperature of said heat responsive means, heating means within heat affecting range of said heat responsive means, and adapted, in an atmospheric environment, to increase the temperature of said heat responsive means sufficiently to open said switch and maintain it in its open condition during prevalence of such atmospheric environment, and adapted to close said switch from an open condition thereof, when said heating means is exposed to a change in environment having a heat conductivity exceeding that of said atmospheric environment, sufficient to cool said heat responsive means below the switch opening temperature of said heat responsive means, and means in response to such closing of said switch, for increasing the capacity of said heating means to a point still below the switch opening temperature of said heat responsive means while said heating means of increased capacity is exposed to such changed environment whereby, upon subsequently removing such changed environment and exposing said heating means of increased capacity to said initial atmospheric environment, said heating means of increased capacity will more rapidly restore said switch to its open condition; means mounting said thermal switch assembly alongside said motor where it will bE subject to immersion in liquid rising about said motor; and means electrically connecting said switch in the power supply circuit to said motor.

Claim 6

A thermal liquid level control system comprising a pump having an electrical motor drive coupled thereto; a thermal switch assembly including thermally actuated switch means involving heat responsive means and a normally closed switch adapted to be opened in response to a rise in temperature of said heat responsive means, heating means within heat affecting range of said heat responsive means, and adapted, in an atmospheric environment, to increase the temperature of said heat responsive means sufficiently to open said switch and maintain it in its open condition during prevalence of such atmospheric environment, and adapted to close said switch from an open condition thereof, when said heating means is exposed to a change in environment having a heat conductivity exceeding that of said atmospheric environment, sufficient to cool said heat responsive means below the switch opening temperature of said heat responsive means, and means in response to such closing of said switch, for increasing the capacity of said heating means to a point still below the switch opening temperature of said heat responsive means while said heating means of increased capacity is exposed to such changed environment whereby, upon subsequently removing such changed environment and exposing said heating means of increased capacity to said initial atmospheric environment, said heating means of increased capacity will more rapidly restore said switch to its open condition; means mounting said thermal switch assembly alongside said motor where it will bE subject to immersion in liquid rising about said motor; and means electrically connecting said switch in the power supply circuit to said motor.

Claim 7

A thermal liquid level control system in accordance with claim 4, characterized by said motor being mounted on said pump, a housing carried by said motor in overhanging relationship thereto with said thermal switch assembly depending from the overhanging portion of said housing.