Abstract: The suction accumulator is pre-charged with oil that is contained ordinarily in accumulator body. This pre-charged oil amount is in addition to the amount of oil normally charged into compressor oil sump, and makes the total amount of oil charge greater. This increased oil helps improve compressor lubrication under boundary lubrication conditions due to liquid refrigerant. Without increasing the amount of oil in the oil sump of the compressor, the quality of the oil is improved with an accumulator with pre-charged oil. That is, additional oil is charged into the accumulator, and the oil return orifice is so located in elevation that a specified volume is contained below the orifice. The volume of the accumulator is increased by providing a side discharge from the accumulator to the suction inlet of the compressor and by extending the accumulator below the suction inlet. In reality though, the volume does not necessarily contain pure oil because oil almost always contains some refrigerant.

Abstract: The suction feed pipe of an accumulator extends above the flow path through a baffle dividing the accumulator thereby permitting the storage of a larger amount of liquid in the accumulator. Where the accumulator has a portion located below the fluid connection going into the compressor, this portion can be used to store a charge of make-up oil to replace the oil distributed in the system during operation without initially overcharging the compressor or of compromising the compressor oil charge.