Abstract: A refrigerant system includes a compressor having a flow of compressor lubricant therein, the compressor compressing a flow of vapor refrigerant therethrough. An evaporator is operably connected to the compressor and includes an environment to be cooled via a thermal energy exchange with a liquid refrigerant in the evaporator. A vaporizer is receptive of a first flow of compressor lubricant and refrigerant mixture from the evaporator having a first concentration of lubricant. The vaporizer uses a flow of compressed refrigerant to separate refrigerant from the first flow. A lubricant sump is receptive of a second flow of compressor lubricant and refrigerant mixture from the vaporizer having a second concentration of lubricant greater than the first concentration. A heat exchanger is receptive of a third flow from the sump and uses evaporator suction gas to cool the third flow, thereby increasing its viscosity before urging the third flow to the compressor.

Abstract: A refrigerant system includes a compressor having a flow of compressor lubricant therein, the compressor compressing a flow of vapor refrigerant therethrough. An evaporator is operably connected to the compressor and includes an environment to be cooled via a thermal energy exchange with a liquid refrigerant in the evaporator. A vaporizer is receptive of a first flow of compressor lubricant and refrigerant mixture from the evaporator having a first concentration of lubricant. The vaporizer uses a flow of compressed refrigerant to separate refrigerant from the first flow. A lubricant sump is receptive of a second flow of compressor lubricant and refrigerant mixture from the vaporizer having a second concentration of lubricant greater than the first concentration. A heat exchanger is receptive of a third flow from the sump and uses evaporator suction gas to cool the third flow, thereby increasing its viscosity before urging the third flow to the compressor.

Abstract: A vaporizer for boiling off a liquid refrigerant from a combined liquid refrigerant/lubricant mixture tapped from an evaporator utilizes hot compressed gaseous refrigerant tapped from a location upstream of the condenser. In a preferred embodiment, the refrigerant is tapped from a compression chamber within the compressor. The hot refrigerant efficiently boils the liquid refrigerant out of the mixture, ensuring high viscosity lubricant. In further features, a return lubricant line from the compressor passes into a sump to further boil off liquid refrigerant.