US 5,345,775 A · Refrigeration system detection assembly

Abstract

A detection assembly is for a refrigeration system which has a cooling unit subject to frost build-up and defrost-to-drain. The assembly includes a first thermal sensor normally exposed to air but also to frost on the cooling unit or water in a plugged drain. A frost or water detection circuit has an input from the first thermal sensor, the detection circuit detects build-up of frost around the first thermal sensor and generates a defrost initiate DI signal which is connected to terminate the refrigeration to the cooling unit and then to initiate a defrost cycle wherein heat is applied to defrost the cooling unit. A second thermal sensor is in good thermal contact with said cooling unit, and a defrost terminate circuit has an input from said second thermal sensor to terminate the defrost cycle. A similar detection circuit determines the existence of ice or water in a plugged drain and terminates the refrigeration or indicates an alarm, or both. The foregoing Abstract is merely a resume of general applications, it is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of the claimed subject matter.

Claims18

Dependent claims

A detection assembly for frost or water in a refrigeration system having a cooling unit subject to frost build-up and defrost water to a drain, said assembly comprising, in combination:

a first thermal sensor normally exposed to air and mounted in said refrigeration system at a location subject to build-up of frost or water;
a detection circuit having an input from said first thermal sensor;
means in said detection circuit to energize said first thermal sensor with a voltage sufficiently high to cause said first thermal sensor to self-heat;
and
means to compare the resistance of said first thermal sensor at two different times to detect the presence of frost or water around said first thermal sensor and to generate a first signal;
said first signal connected to terminate the refrigeration to said cooling unit.

3 more elements

Dependencies are inferred from the claim text.

Refrigeration system detection assembly

Life of this patent

Refrigeration system detection assembly

Life of this patent

Abstract

Claims18