Injection system and method for refrigeration system compressor

A refrigeration system comprising:

• a compressor having a compression mechanism with compression cavities therein, a suction port, and a discharge port, said compressor compressing a refrigerant flowing therethrough to a discharge pressure greater than a suction pressure;
• a flash tank into which refrigerant discharged from said compressor through said discharge port flows, said flash tank separating liquid refrigerant from vapor refrigerant;
• a first flow path communicating with said flash tank and through which a first stream of refrigerant exits said flash tank and is supplied to said suction port and supplied to one of a plurality of intermediate-pressure locations in said compression cavities, said plurality of intermediate-pressure locations operating at a pressures greater than said suction pressure and less than said discharge pressure, said first stream being predominantly refrigerant vapor when injected into one of said plurality of intermediate-pressure locations;
• and
• a second flow path communicating with said flash tank and through which a second stream of refrigerant exits said flash tank and is injected into one of said plurality of intermediate-pressure location in said compression cavities, said second stream being predominately liquid refrigerant when injected into one of said plurality of intermediate-pressure locations.