04621502 is referenced by 51 patents and cites 10 patents.

A refrigeration system for a display case including electronic means for controlling an expansion valve and a refrigerant compressor used in the system. The expansion valve is cycled between open and close positions to modulate refrigerant flow into an evaporator coil. A microprocessor controls the operation of the expansion valve in response to: (a) the relationship of the temperature of air that has passed over the evaporator coil to multiple upper and lower limits (b) time integrated temperature deviations beyond preselected limits (c) upward or downward trend of the differential in temperature in the refrigerant during its flow through the evaporator coil, and (d) extreme deviation of the temperature of air that has passed over the evaporator coil. Compressor cut-in and cut-out pressures are also adjusted by the control in response to these air and refrigerant temperatures. In addition, the various limits may be adjusted according to a night setback schedule, and an alarm is provided to warn of relatively long-term deviation of the controlled temperature.

Title
Electronic temperature control for refrigeration system
Application Number
6/690606
Publication Number
4621502
Application Date
January 11, 1985
Publication Date
November 11, 1986
Inventor
Kwok K Fung
Niles
MI, US
Fayez F Ibrahim
Niles
MI, US
Assignee
Tyler Refrigeration Corporation
MI, US
IPC
G01K 13/00
F25B 49/00
F25B 41/04
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