Classification by working principle and working principle of air compressor

Core principle : By directly reducing the volume of a closed chamber to compress air, the gas density per unit volume is increased to raise the pressure. This is currently the most widely used type in industrial applications.

Common subcategories are as follows:

• A reciprocating air compressor consists of a crank, piston, cylinder, and intake/exhaust valves. Its working principle is similar to that of an air pump: when the piston moves backward, it creates a vacuum in the cylinder to draw in air; when it moves forward, the volume decreases, compressing the air. Once the set pressure is reached, the compressed air is discharged. The air production is pulsating, and a pressure-stabilizing air tank is usually required.
• Features: Wide pressure range (0.5MPa to over 20MPa ); low purchase and maintenance costs for small-power models; suitable for low-flow, high-pressure, intermittent gas usage scenarios. Disadvantages: High noise level and numerous easily damaged parts.

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• Screw air compressors operate by rotating a pair of meshing male and female rotors: air enters the closed chamber formed by the rotor teeth from the inlet end, and as the rotors rotate, the volume of the closed chamber gradually decreases from the inlet end to the outlet end, and the air is continuously compressed and discharged, a process that is smooth and pulsation-free.

• Based on the number of screws, screw air compressors can be divided into twin-screw and single-screw types. Over 99% of screw air compressors are twin-screw type , currently holding nearly 100% market share in industrial applications with flow rates of 1-60 m³/min and pressures ≤2.0 MPa . They are characterized by stable operation, low noise, and high reliability, making them suitable for continuous production and the dominant product in the current market.

• Other volumetric types include vane type (which relies on the sliding vanes on an eccentric rotor to form a compression chamber), vortex type (which forms a compression chamber through the meshing of moving and stationary vortex disks), membrane type, etc., which are mostly used in scenarios with low flow rates and high cleanliness requirements.

Core principle : The high-speed rotation of the impeller imparts kinetic energy to the air, which is then decelerated in the diffuser to convert the kinetic energy into pressure energy, thereby increasing the air pressure.

Common subcategories are as follows:

• Centrifugal air compressors typically contain 2-3 irregularly shaped impellers with speeds of 5000-15000 r/min . Air gains kinetic energy as the impellers rotate at high speed and then enters the diffuser for deceleration and pressure increase. Multi-stage compression is usually used to gradually increase the pressure.

• Features: High flow rate, no mechanical contact wear on core components, low maintenance cost, parts life up to 15 years , completely oil-free, high energy efficiency, suitable for large-scale industrial scenarios with high flow rate and low pressure. The disadvantage is high initial installation cost.
• Other types include axial flow (with the main airflow along the axis and a larger flow rate) and mixed flow, which are mostly used in specific large-scale industrial scenarios.
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In addition to their core working principles, air compressors can also be classified according to different dimensions to adapt to different scenario requirements: