Air Compressor

A device that provides a volume of air at a pressure above atmospheric pressure.

The ideal case is to compress air isothermally, in practice it is impossible to compress the air isothermally, because from the nature of things the operation must be performed quickly, giving no time in which to remove the heat produced during compression.

Air Dryer

A devise that removes moisture from compressed air.


The amount of air flow delivered under specific conditions, usually expressed in cubic feet per minute (CFM).


This is the distance between the top of the cylinder and the piston at the top of the compression stroke. This should be as small as possible since its effect is to reduce the efficiency.

During the suction stroke the compressed air in the clearance space of expands to volume og, and less atmospheric air is drawn into the cylinder, the volume being only gh.

The result is that the compressor must make a greater number of strokes to deal with the same volume of air, with a resulting greater loss by friction.

Cubic Feet Per Minute (CFM)

Volumetric air flow rate.


A material having a large proportion of surface pores, capable of attracting and removing water vapour from the air.

Discharge Temperature

The air temperature at the discharge flange of the compressor.

Pressure Dew Point

For a given pressure, the temperature at which water will begin to condense out of air.

Reciprocating Compressor

Compressor in which the compressing element is a piston having a reciprocating motion in a cylinder.

See also: Air Motor, Compressed Air, Compressed Air Dryer, Compressor, Reciprocating Air Compressor.

Previous PageView links to and from this pageNext Page

Subjects: Tools