Air compressors can be classified in various ways, with the core dimensions being working principle, structural form, pressure rating and lubrication method. Different types of air compressors vary greatly in their applicable scenarios.

(I) Classification by Working Principle (the core classification)

Positive-displacement air compressors: Achieve air compression by changing the gas volume. They are the most widely used, accounting for more than 90% of the market share.

Reciprocating piston air compressors: Compress air in the cylinder by the reciprocating motion of a piston inside it. Featuring a simple structure, low cost and a wide pressure range (capable of high even ultra-high pressure), they are suitable for small and medium-sized enterprises, maintenance stations and other scenarios. Their drawbacks include high noise, obvious vibration and the need for regular replacement of vulnerable parts such as piston rings.

Screw air compressors: Divided into twin-screw and single-screw types, they compress air by the meshing rotation of two (or one) screw(s) to squeeze the air. With advantages of high efficiency, energy saving, low noise, stable operation and easy maintenance, they are the most commonly used type in current industrial production, suitable for large factories, assembly lines and other scenarios requiring continuous and stable air supply.

Scroll air compressors: Realize air compression through the relative motion of an orbiting scroll and a fixed scroll to form and gradually reduce sealed volumes. Characterized by small size, extremely low noise and high energy efficiency, they are suitable for noise-sensitive scenarios (e.g., medical care, laboratories, precision electronics). Their disadvantages are relatively limited pressure and air displacement.

Dynamic air compressors: Transfer mechanical energy to air via a high-speed rotating impeller to accelerate air flow, then convert kinetic energy into pressure energy through a diffuser. They are suitable for scenarios with large air displacement and medium-low pressure.

Centrifugal air compressors: Compress air by centrifugal force, with large air displacement, stable pressure and smooth operation. They are suitable for large factories, power plants, chemical industry and other scenarios requiring a large amount of continuous air supply. Their drawbacks are complex structure, high initial investment and poor adaptability to working condition changes.

Axial flow air compressors: Push air to flow and compress it through axial flow impellers, with extremely large air displacement and low pressure. They are mainly used in special scenarios such as aerospace and large wind tunnels.

(II) Classification by Lubrication Method

Oil-lubricated air compressors: Require lubricating oil to participate in the compression process, with good lubrication and sealing effects and a long service life. However, the output compressed air contains a small amount of oil and needs subsequent purification treatment, making them suitable for scenarios with low air quality requirements (e.g., construction, mining).

Oil-free air compressors: Divided into "oil-free" and "oil-less lubrication" types, they do not use lubricating oil during compression and output compressed air with high cleanliness. They are suitable for medical care, food, precision electronics, pharmaceutical and other scenarios with extremely high air quality requirements, with the disadvantages of higher cost and stricter maintenance requirements.

(III) Classification by Pressure Rating

Low-pressure air compressors: Discharge pressure ≤ 1.0MPa, suitable for ordinary pneumatic tools (e.g., wrenches, spray guns), ventilation and cooling and other scenarios.

Medium-pressure air compressors: 1.0MPa ＜ discharge pressure ≤ 10MPa, suitable for chemical industry, mechanical processing, pneumatic control systems and other scenarios.

High-pressure air compressors: Discharge pressure ＞ 10MPa, suitable for special scenarios such as high-pressure gas cylinder inflation, diving and aerospace.