In the market, there two main kinds of screw air compressor, single stage compressor and two-stage compressor. But in the actual use, large power or massive air displacement air compressor, often use the two-stage compressor.
As the name shows, two-stage compression using dual air-end to compressed air. The air enters the first stage compression, mixed with lubricating oil in the cylinder, in the meantime, and was compressed to interstage pressure. In the intermediate cooling channel, the compressed air cooled by the cooling spray; the temperature was significantly reduced. Then the compressed air enters the secondary compression, compressed to the final exhaust pressure. Finally, the compressed air is discharged through the exhaust flange to complete the compression process.
Because when the temperature is high, the density of the gas is low, the compression needs do more work, so the isothermal compression was most power-saving during the compression. Not only that, but isothermal compression also reduces the temperature of the compressed gas, making the operation of the air compressor more reliable. But isothermal compression is impossible to achieve in actual work. And two-stage compression was mostly close to isothermal compression.
