ABSTRACT
Compressors and pumps, often called working machines, are used to move materials for a large variety of purposes. Compressors are machines that increase the pressure of a gas through input of mechanical work. Similarities exist between the design of compressors and the design of pumps. Dynamic machines include centrifugal compressors and axial compressors. Classifications for liquid pumps are similar to compressors. Dynamic compressors handle significant flows at relatively high speeds. Multistage compressors are required for higher pressures. Centrifugal compressors require a lubricant for gear sets and the bearings supporting the lobe shafts. There are several types of reciprocating compressors. The driving end of the compressor includes the crankcase and running gear. The term “screw compressor” most often references the double-helical, also called twin-screw, compressor. Twin-screw compressors are designed as constant volume and with a built-in compression ratio. Liquid-injected single-screw compressors are constant-volume, variable-pressure machines.
