Multi-stage gas compressor system and desuperheater means therefor

Abstract

A refrigeration system comprises an evaporator which feeds uncompressed vapor to a first (low) stage compressor, a second (high) stage compressor which receives low compression vapor from the first stage and feeds high compression vapor to a condenser, and a receiver which receives liquid from the condenser and ultimately feeds it to the evaporator. Desuperheater apparatus, comprising a pressure vessel (subcooler) and a heat exchanger, is provided to remove excess heat (superheat) from the compressed vapor fed by the first stage to the second stage to thereby improve thermal efficiency of the system and to reduce the mass of refrigerant to be handled by the second stage thereby enabling use of a smaller, more economical second stage compressor. The pressure vessel contains a bath of liquid which is supplied from the receiver and then fed to the evaporator. Compressed vapor from the first stage is forced through and cooled by the liquid bath in the pressure vessel and is then fed to the second stage, along with vapor which evaporates from the liquid bath. The heat exchanger has one side through which compressed vapor from the first stage passes (and is cooled) on its way to the pressure vessel. The heat exchanger has another side through which an over-supply of liquid is pumped (or gravity fed) from the receiver and then returned to the receiver as a liquid/vapor mixture.