What are the two main classes of compressors?

The two main classes of compressors are best categorized as positive displacement and dynamic. This classification distinguishes how each type of compressor operates to move air or other gases.

Positive displacement compressors work by mechanically reducing the volume of gas. In these systems, gas is trapped in a chamber and then compressed when the volume of that chamber is reduced. Examples include reciprocating and rotary compressors. These compressors deliver a fixed amount of gas with each cycle, regardless of the pressure in the discharge line.

On the other hand, dynamic compressors, which can also include centrifugal and axial compressors, operate by adding kinetic energy to the gas through high-speed rotation. As the gas flows through these machines, its velocity increases, which is then transformed into increased pressure. Dynamic compressors typically provide a continuous flow of gas and are suited for high-flow applications where the pressure differential is relatively low.

This classification is fundamental in understanding compressor design and application, as it helps in selecting the right type of compressor for specific industrial needs.