| 摘要 |
An economical method for converting a compression type refrigeration system designed for the use of R-12 refrigerant, comprising an evaporator, a compressor rated for R-12, a condenser, and a receiver, to the use of R-22 refrigerant without replacing the compressor or other major pieces of equipment. The retrofit comprises the installation of a pressure regulator in the suction line to the compressor and the balancing of the regulator to the operating limitations of the compressor motor; the installation of a line into the body of the compressor sufficient to inject liquid refrigerant into the compressor for cooling purposes; and the attachment of a desuperheating control to the refrigerant injection line to control the amount of refrigerant injected based upon the temperature inside the compressor. In many embodiments it is also advisable to install a pressure regulator at the outlet of the evaporator to maintain design temperature in the evaporator. In the preferred embodiment of the invention, a pump is also installed in the line between the receiver and the evaporator to prevent flashing in that line, reduce the amount of refrigerant needed to decrease the load on the compressor and eliminate the need for imposing an artificial head pressure for refrigerant circulation.
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