A blower is typically a machine that operates below 20 psig. Blowers can be stage to achieve higher discharge pressures, but no internal compression takes place.Blowers are typically defined as positive displacement type machines.

Industrial fans and blowers are machines whose primary function is to provide and accommodate a large flow of air or gas to various parts of a building or other structures. This is achieved by rotating a number of blades, connected to a hub and shaft, and driven by a motor or turbine.