What are the two main classifications of compressors?

The correct classification of compressors as positive displacement and non-positive displacement provides a clear understanding of how these machines operate. Positive displacement compressors work by trapping a fixed amount of air or gas and then forcing it into a smaller volume, resulting in increased pressure. This process often involves mechanisms like pistons or rotors that physically compress the gas. On the other hand, non-positive displacement compressors, which include dynamic compressors, use high-speed rotational motion to impart energy to the gas, increasing its velocity as it passes through the impeller, thus compressing it based on kinetic energy rather than a fixed volume.

By understanding this classification, one can better grasp the operational principles and applications of various compressor types, tailoring their use to specific industrial needs. This is vital for millwrights who must select and maintain the appropriate compressor for different tasks.