Crocker M.

Compressors are in wide use throughout the world in household appliances, air-conditioning systems in buildings, vehicles and industry. Various compressors are used for different applications and there are a large number of quite different designs. The compressor design adopted for each application depends upon various factors, including the gas or working fluid which must be compressed, and the discharge pressure and flow rates that need to be achieved. The four main types of compressors are reciprocating piston, rotary, axial and centrifugal. The noise generated by the piston type depends upon several factors, the most important being the reciprocating frequency and multiples, number of pistons, valve dynamics, and acoustical and structural resonances. The noise produced by the rotary types depends upon rotational frequency and multiples, numbers of rotating elements, flow capacity and other flow factors. The noise generated by centrifugal and axial compressors also depends upon rotational frequency; the number of rotating compressor blade elements, flow speed and volume flow rate, however, are also important factors. This paper presents a review of compressor types, main operational features, methods of identifying noise and vibration sources and paths. Finally the paper describes some case histories of efforts to control noise and vibration in different compressor types.