| 摘要 |
A refrigerant recovery unit is provided in which four distinct refrigerant flow paths are automatically controlled by the unit components to perform four separate and distinct functions. In a liquid refrigerant path, liquid refrigerant is recovered from the discharge side of a disabled unit through the refrigerant recovery unit by use of the differential pressure between the disabled unit and the refrigerant receiving can. In a primary vapor path, evacuation of gaseous refrigerant from the high and low sides of the disabled unit is achieved by use of a compressor in the recovery unit which produces a differential pressure to induce flow. This differential pressure is produced solely by the recovery unit compressor until such time as the intake pressure of the compressor reaches approximately 4 inches Hg. vacuum. When the compressor intake pressure reaches 4 inches Hg. vacuum, the system automatically switches to a secondary vapor path for recovering gaseous refrigerant from the high and low side of the disabled unit by sequencing an external vacuum pump in series with the compressor of the recovery unit to produce the differential pressure inducing flow. This differential pressure is continued until the intake pressure reaches a desired vacuum level of up to 29.9 inches Hg. Finally, to recover gaseous refrigerant or non-condensible gas from the high and low side of the disabled unit after the desired vacuum level has been reached, differential pressure is obtained by connecting the external vacuum pump through the recovery unit without using the compressor. This same path can be used to remove non-condensible gas from a receiving can as well.
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