The natural air enters the first stage of compression through the air filter, mixes with a small amount of lubricating oil in the compression chamber, and compresses the mixed gas to the inter-pole pressure. The compressed gas enters the cooling channel and comes into contact with a large amount of oil mist, which greatly reduces the temperature. The cooled compressed gas enters the second stage rotor for secondary compression and is compressed to the final exhaust pressure. Finally, the compressor is discharged through the exhaust flange to complete the entire compression process.

After the air is compressed in the first stage, the air is subjected to isobaric compression to reduce the compression work by strengthening the oil injection cooling to reduce the suction temperature of the second stage.

Two-stage compression generally uses an equal pressure ratio to set the interstage pressure, so the compression ratio of each stage is much lower than the single-stage compression ratio, the backflow leakage between the rotors is greatly reduced, and the volumetric efficiency and adiabatic efficiency are greatly improved. Correspondingly, the compressed gas production is increased.