What are the types of air compressors?

Air compressors can be divided into many types according to different classification standards. The following are the main categories and their corresponding types:

1. classified by working principle

1. positive displacement compressor

   • reciprocating compressor: Also known as piston compressor, its compression element is a piston that reciprocates in the cylinder to compress air. The compressor has simple structure and high reliability, and is suitable for small and medium gas volume occasions. However, it has disadvantages such as large vibration, high noise, and discontinuous exhaust.
   • rotary compressor: Compression is achieved by the forced movement of the rotating element. It mainly includes screw type, slide type and scroll type.
     • Screw compressor: It is one of the most widely used rotary air compressors. It compresses air through two intermeshing screws. It has the advantages of stable operation, low noise, high reliability, and large air volume adjustment range.
     • vane compressor: Use the sliding vane to slide in the rotor slot to achieve air compression. Its structure is simple and small in size, but the sliding vane wears quickly and has a relatively short life.
     • scroll compressor: With its high efficiency, low noise, small size and other characteristics, it has been applied in some occasions with high requirements for space and noise.

2. power compressor

   • centrifugal compressor: Rely on the high-speed rotating impeller to do work on the air, so that the air obtains kinetic energy and pressure energy under the action of centrifugal force, so as to realize the compression of the air. It has the advantages of large gas volume, compact structure, stable operation, and no oil pollution. It is suitable for large industrial enterprises and occasions with large air demand.
   • axial flow compressor: The air flows along the axial direction and compresses the air through a series of moving blades and static blades. It has the advantages of large flow, high efficiency, and small footprint, but it has high requirements for manufacturing processes. Usually used in large power plants, metallurgy and other industries.
   • mixed-flow compressor: The shape of its rotor combines some characteristics of both centrifugal and axial flow.
   • jet compressor: Use high-speed gas or steam jet to take away the inhaled gas, and then convert the velocity of the mixed gas into pressure on the diffuser.

2. classified by lubrication method

1. oil air compressor: Lubricating oil is used to reduce friction, cooling and sealing during compression. It has the advantages of relatively low price and simple maintenance, but the output air will contain a certain amount of oil, which needs to be processed to meet the requirements of certain occasions.
2. Oil-free air compressor: No lubricating oil is used during the compression process to ensure that the output air is oil-free and pollution-free. There are mainly dry oil-free air compressor and water lubricated oil-free air compressor. The dry oil-free air compressor avoids the use of lubricating oil through special materials and structural design, but its price is relatively high and the maintenance cost is also high. Water-lubricated oil-free air compressor uses water as lubricating medium, which has the advantages of environmental protection, energy saving and low cost. Oil-free air compressors are widely used in food, medicine, electronics and other industries with high air quality requirements.

Classification of 3. by other criteria

1. classification by use such as refrigerator compressor, air conditioning compressor, refrigeration compressor, oil field compressor, natural gas filling station compressor, etc.
2. Classification by type: such as fixed, mobile, closed, etc.
3. Classification by exhaust pressure such as blower, low pressure air compressor, medium pressure air compressor, high pressure air compressor, etc.
4. Classification by displacement: Such as micro, small, medium, large, etc.

In addition, there are some special types of air compressors, such as liquid-piston compressors, Roots dual-rotor compressors, etc. Each of these compressors has its own characteristics and application areas, and users can choose according to actual needs.