What are the two main classifications of compressors?

The correct classification of compressors is based on their operational principles, which can be categorized as positive displacement and kinetic displacement. Positive displacement compressors work by mechanically trapping a fixed amount of air or gas and forcing it into a smaller volume, increasing pressure. Examples of positive displacement compressors include reciprocating and rotary types. Kinetic displacement compressors, on the other hand, utilize a rotating element to impart velocity to the air or gas, which is then converted into pressure. This classification highlights the different mechanisms through which compressors achieve the desired output pressure and flow.

While the other classifications mentioned focus on specific types (e.g., reciprocating and rotary), stages of operation, or particular designs like piston and screw compressors, they are subsets within the broader categories of positive displacement and kinetic displacement. Understanding the main classifications helps in grasping the fundamental principles governing how various compressor types function.