The reasons for air compressor classification mainly include the following points:

1.Save power consumption: Multi-stage compression uses an intercooler to cool the compressed gas after the first stage of compression, and then enter the next stage after the temperature is reduced, thereby increasing the density and facilitating further compression. This can greatly save power consumption. The more stages there are, the closer it is to isothermal compression, thus saving more power consumption.

2.Improve volume utilization: In single-stage compression, the clearance volume in the cylinder will lead to reduced volume utilization efficiency. Using multi-stage compression can reduce the compression ratio of each stage. The residual gas in the clearance volume only needs to expand slightly to reach the suction pressure, which effectively improves the utilization of the cylinder volume.

3.Reduce exhaust temperature: As the compression ratio increases, the exhaust temperature will rise, and too high exhaust temperature may be detrimental to machine operation. Multi-stage compression can effectively reduce the exhaust temperature, especially in oil-lubricated compressors, to prevent the reduction of lubricating oil viscosity, carbon deposition, wear and potential explosion risks caused by excessive temperature.

4.Reduce the gas force acting on the piston rod: In single-stage compression, higher pressure acts on the piston rod, resulting in greater force. Multi-stage compression can reduce the force, which may make the mechanical structure lighter and improve mechanical efficiency.

5.Technical requirements and standards: The technical requirements for air compressors include motor power, exhaust pressure, volume flow, dew point, gas oil content, input specific power, etc. There are clear standards for energy saving and environmental protection. For example, GB19153-2019 "Energy efficiency limit values and energy efficiency grades for positive displacement air compressors" stipulates the energy efficiency grades of air compressors in different power and pressure ranges.

6.Reliability: From the perspective of reliability, if the head processing accuracy is high, the internal gap can be effectively controlled and internal leakage can be reduced, then single-stage compression may be more in line with the user's interests because it has fewer parts and a simpler structure.

In actual operation, whether to adopt graded compression requires a comprehensive evaluation based on specific working pressure, required gas volume, compression medium and other conditions.