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US 2003/0110785 A1Published application
System and method for low side pump down in mobile refrigeration unit
AssigneeCarrier Corporation
InventorsWillard Edwin Williamson, Paul Valentine Weyna, Richard Alan Simone
Life of this patent
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Abstract
A microprocessor controlled system performs low pressure side pumpdown with the assistance of a service technician. When the refrigerant in the system is transferred to the high pressure side, the low pressure side is available for servicing by the technician.
Claims15
An apparatus for low pressure side pumpdown processing of refrigerant in a mobile refrigeration unit, comprising:
- a compressor;
- an engine which powers said compressor;
- a microprocessor connected to said engine and to a plurality of valves and sensors in said unit;
- means, responsive to said microprocessor, for minimizing an amount of refrigerant mixed with oil in said compressor;
- and
- transferring means, responsive to input from a user, for transferring substantially all of said refrigerant from a low pressure side of said unit to a receiver.
3 more elements
A method for low pressure side pumpdown processing of refrigerant in a mobile refrigeration unit, comprising the steps of:
- providing a microprocessor connected to a plurality of valves;
- providing a compressor for said unit;
- minimizing an amount of said refrigerant mixed with oil in said compressor;
- opening and closing specified ones of said plurality of valves;
- running, in response to said microprocessor, a compressor to pump refrigerant in said unit into a receiver;
- monitoring a suction pressure and providing results of said monitoring to said microprocessor;
- shutting down said compressor, in response to said microprocessor, after said suction pressure falls below a first predetermined point;
- opening, in response to said microprocessor, an electronic evaporator expansion valve and monitoring said suction pressure to see if said suction pressure remains below a second predetermined point;
- signaling said microprocessor to resume normal operation;
- and
- opening and closing, in response to said microprocessor, specified ones of said plurality of valves to return said unit to normal operation.
8 more elements
Dependencies are inferred from the claim text.