| 摘要 |
An economizer arrangement for ice making reverse cycle refrigeration system of the type employing hot-gas defrosting, including a condenser, a receiver to receive liquid refrigerant, a plural tube evaporator having an internal refrigerant chamber in each tube and an expansion valve through which the refrigerant flows into the evaporator tubes during a freezing cycle of the system to cause ice formation on ice-making surfaces of the evaporator means in heat exchange relation with the refrigerant chamber. A rotary screw type compressor supplying to the condenser and has an economizer port at a location along the screw where the pressure builds up to a selected level, a refrigerant valve passes the condenser and routes hot-gas refrigerant during a harvest defrost cycle to the evaporator tubes, and a relief conduit tube communicates the refrigerant chambers of the evaporator tubes with the economizer port. The relief conduit having a relief regulator valve therein set to relieve the pressure being built up in the refrigerant chambers during the defrost cycle to a selected level to provide optimum pressure for ice harvest during defrost by controlling this pressure and transferring most on the refrigeration load of pulling the defrosted circuit back down to normal refrigeration temperatures to the economizer port of the screw compressor.
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