Virtually every phase of modern manufacturing depends upon compressed air. Examples are linear actuators, pneumatic tools, clamping devices, and air lifts. Process service is defined as any application in which air or other gas enters into a process itself.
Examples are combustion, liquification of oils, and refrigeration.
Control applications are those in which air or gas triggers, starts, stops, modulates, or otherwise directs machines or processes. Positive Displacement Compressors Positive displacement compressors are machines in which successive volumes of air or gas are confined within a closed space and elevated to a higher pressure. In one type of positive displacement compressor, the pressure is increased while the volume of the closes space is decreased. This type includes reciprocating compressors, sliding vane rotary compressors, and rotary screw compressors. In another type, which includes the rotary, two impeller design, the trapped volume of air or gas is transferred from the suction pressure to the point of discherge without reduction in volume.