Oil separator for separating and collecting oil entrained in refrigerant

Abstract

An oil separator operates to remove oil entrained in a refrigerant being circulated in a refrigeration system, especially a system using a screw-type compressor. The oil separator generally comprises a vessel having a chamber therein and a perforated plate on which oil coalescing elements are mounted divides the chamber into a lower primary oil separator section and an upper secondary oil separator section. A mixture inlet pipe extends through a side of the tank into the lower section for admitting a pressurized mixture of refrigerant and oil. A refrigerant gas outlet port is provided in the upper section for expelling refrigerant from which the oil has been separated. An oil outlet port is provided in the lower section for expelling oil collected in an oil sump at the bottom of the lower section. The inlet mixture pipe defines a passage which comprises a straight horizontal portion and a curved and downwardly sloped portion which terminates in a discharge opening near a curved inner surface of the vessel wall. As the mixture of refrigerant gas with oil entrained therein flows through the passage, oil droplets separate from the refrigerant under centrifugal force along the outer curved wall surface of the passage, exit by gravity and under the force of the gas stream against the curved inner surface of the vessel wall in the lower section and collect in the oil sump for expulsion through the oil outlet port for re-use in the compressor. Oil trapped by the coalescing elements as the gas moves from the lower section to the upper section through the filter elements also returns from the upper section into the oil sump.