Kenneth C Adams
Engineers at Lakeshore Dr, Paris, TX

5247803, Sep 28, 1993

Apr 27, 1992

7/874617

Kenneth M. Adams - Paris TX
Ronald E. Keith - Irving TX

Technical Chemical Corporation - Dallas TX

F25B 4500

62 77

A refrigerant recovery system comprises a compressor driven recovery machine having inlet and outlet ports, a primary refrigerant receiving and storage vessel having liquid and vapor ports, and a secondary refrigerant receiving and storage vessel having an inlet. During the refrigerant recovery process the refrigerant circuit outlet is coupled to the primary vessel liquid port, the primary vessel vapor port is coupled to the recovery machine inlet port, and the recovery machine outlet port is coupled to the vapor inlet of the secondary vessel. Operation of the recovery machine draws liquid refrigerant into the primary vessel at a high flow rate while withdrawing refrigerant vapor from the primary vessel, converting the withdrawn vapor to liquid refrigerant, and forcing the liquid refrigerant into the secondary vessel at a liquid refrigerant flow rate substantially less than the liquid refrigerant inflow rate to the primary vessel. The use of the primary vessel interposed between the refrigerant circuit and the recovery machine greatly increases the machine's refrigerant recovery rate compared to the conventional connection of the machine only to a refrigerant receiving and storage vessel at its outlet end. Each of the vessels is provided with a safety cutoff switch which, via electrical circuitry interconnected between the switches and the machine compressor, operates to shut off the machine compressor when the liquid refrigerant level in the vessel reaches a predetermined maximum level.