Air compressors can be classified in various ways based on factors such as their working principle, structural form, and performance parameters. Here are some common classification methods:

1. Classification based on the working principle:
   • Positive Displacement Air Compressors: These compressors work by reducing the volume of air to increase its pressure. Examples include reciprocating compressors (piston, diaphragm) and rotary compressors (sliding vane, screw).
   • Dynamic Air Compressors: These compressors use rotating elements to accelerate and convert the kinetic energy of air into pressure energy. Examples include centrifugal compressors, axial compressors, and mixed-flow compressors.
2. Classification based on the output pressure:
   • Low-Pressure Air Compressors: Up to 0.2-1.0 MPa.
   • Medium-Pressure Air Compressors: 1.0-10 MPa.
   • High-Pressure Air Compressors: 10-100 MPa.
   • Ultra-High-Pressure Air Compressors: Above 100 MPa.
3. Classification based on the output flow rate (displacement):
   • Micro and Small Air Compressors: Up to 1-10 m3/min.
   • Medium Air Compressors: 10-100 m3/min.
   • Large Air Compressors: Above 100 m3/min.
4. Classification based on the cooling method:
   • Water-Cooled Air Compressors: These compressors use a water-based cooling system.
   • Air-Cooled Air Compressors: These compressors use fans for cooling.
5. Classification based on the driving source:
   • Electric Motor-Driven Air Compressors.
   • Diesel Engine-Driven Air Compressors.
6. Classification based on the lubrication method:
   • Oil-Free Air Compressors.
   • Oil-Lubricated Air Compressors: These can be further classified into splash lubrication and forced lubrication (with oil pump and lubricator).
7. Classification based on the configuration:
   • Fixed Air Compressors: Can be with or without a foundation.
   • Mobile Air Compressors.