Pressure control override

Patent · Tue Jan 12 04:00:00 EST 1988

OSTI ID:5403357

Mitchell, C F

This patent describes a pressure control override apparatus for overriding a conventional pressure control starting switch on a refrigeration system. The refrigeration system has a compressor with a pump-down cycle, an evaporator, a liquid line for conducting a compressed refrigerant between the compressor and the evaporator, and an electrically activated solenoid valve mounted in the liquid line for alternatively opening the liquid line when power is applied to the valve and closing the liquid line when power is removed from the valve. The apparatus comprises: a first circuit; means for alternatively powering the first circuit when power is applied to the solenoid valve, and for removing power from the first circuit when power is removed from the solenoid valve; an ambient temperature sensing switch in the first circuit and configured to sense the ambient temperature at a location substantially adjacent the compressor, the switch configured to close the first circuit when the ambient temperature falls below a preselected level, and to open the first circuit when the ambient temperature raises above the preselected level; and a second circuit configured to start the compressor separate from the pressure control starting switch when the second circuit is closed, including a relay switch in the second circuit configured to close the second circuit only when both the first circuit is closed and the first circuit is powered by the powering means, and a normally closed high pressure safety switch in the second circuit configured to open the second circuit when the pressure in the liquid line reaches a predetermined excessive level.

• Assignee: NOV; NOV-88-003047; EDB-88-078294
• Patent Number(s): US 4718246
• OSTI ID: 5403357
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320106* -- Energy Conservation
Consumption
& Utilization-- Building Equipment-- (1987-)
COMPRESSORS
CONTROL
CONTROL EQUIPMENT
ELECTRIC COILS
ELECTRICAL EQUIPMENT
EQUIPMENT
EVAPORATORS
FLOW REGULATORS
FLUIDS
PRESSURE CONTROL
REFRIGERANTS
REFRIGERATORS
SOLENOIDS
VALVES
WORKING FLUIDS