Editing Compressor (section)

==Staged compression==
In the case of centrifugal compressors, commercial designs currently do not exceed a compression ratio of more than 3.5 to 1 in any one stage (for a typical gas). Since compression raises the temperature, the compressed gas is to be cooled between stages making the compression less adiabatic and more isothermal. The inter-stage coolers (intercoolers) typically result in some partial condensation that is removed in [[vapor–liquid separator]]s.

In the case of small reciprocating compressors, the compressor flywheel may drive a cooling fan that directs ambient air across the [[intercooler]] of a two or more stage compressor.

Because rotary screw compressors can make use of cooling lubricant to reduce the temperature rise from compression, they very often exceed a 9 to 1 compression ratio. For instance, in a typical diving compressor the air is compressed in three stages. If each stage has a compression ratio of 7 to 1, the compressor can output 343 times atmospheric pressure (7 × 7 × 7 = 343 [[atmosphere (unit)|atmosphere]]s). ({{convert|343|atm|MPa ksi|sigfig=3|abbr=on|lk=out|disp=or}})