Patent ID: 6973797

Claim:
A refrigeration system, the system comprising: a refrigeration circuit comprising at least one compressor, a condenser, and an evaporator communicably connected in a closed loop, the at least one compressor comprising: a compression mechanism for compressing a refrigerant gas, the compression mechanism having a suction inlet, a discharge outlet and at least one stage of compression between the suction inlet and discharge outlet; the at least one stage of compression including at least one capacity control valve configured and disposed to control a capacity control opening in the compression mechanism, the capacity control opening communicably connecting the at least one stage of compression to at least one bypass circuit; and the at least one bypass circuit being in fluid communication with the capacity control opening and the suction inlet; and an economizer circuit, the economizer circuit comprising: a flash tank having a refrigerant inlet in fluid communication with the condenser, a liquid outlet in fluid communication with the evaporator, and a gas outlet in fluid communication with the at least one stage of compression; a gas return line being separate from the at least one bypass circuit, the gas return line in fluid communication with the gas outlet and the at least one stage of compression; and a first modulating valve disposed in the gas return line to adjustably control the flow of gas from the gas outlet of the flash tank to the at least one stage of compression; and a control panel for controlling operation of the at least one capacity control valve and the first modulating valve.