Compressors are manufactured in various sizes (depending on requirements) and are classified according to their method of operation as reciprocating, rotary, and centrifugal. The function of any compressor is to provide the necessary pumping action to remove the refrigerant gas from the evaporator, compress the gas, and finally discharge the gas into the condenser, where it is liquefied. The pumping action of the compressor provides the means of lifting the gas from the condition of low to that of high pressure, and the volume of gas to be compressed is dependent on the compressor piston displacement. The compressor and component parts are shown in Figure 7-2.
