Air compressing machinery must be chosen for a particular application not only with regard to the duty and performance expected of the plant but also to its future and possibly extended use. This paper describes the different types of air compressing plant available and indicates the features likely to influence choice. The many compressors available for use in industry can be classified in three main groups, viz. (a) rotary compressors, (b) reciprocators, and (c) flow machines, either centrifugal or axial. These three groups comprise 10 main types.
