When the working pressure of the gas is required to be high, it is not only uneconomical, but sometimes impossible to achieve single-stage compression, and multi-stage compression must be employed. Multi-stage compression is the process of starting the gas from the inhalation and after several boosts to achieve the required working pressure.Why do air compressors require staged compression?
1. Save power consumption
With multi-stage compression, the compressed gas can be cooled by the first stage after the first stage compression to reduce the temperature before entering the next stage cylinder. The temperature is lowered and the density is increased, so that it is easy to further compress, and the power consumption can be greatly saved compared with the one-time compression. Therefore, under the same pressure, the area of multi-stage compression work is less than that of single-stage compression. The more the number of stages, the more power consumption is closer to isothermal compression.
Note: The air compressor of the oil jet screw air compressor is very close to the constant temperature process. If the compression is continued after the saturation state is reached, the condensed water will be precipitated. If these condensed water enters the oil separator (tank) together with the compressed air, the cooling oil will be emulsified, which will affect the lubrication effect. As the condensate continues to increase, the oil level will continue to rise. Finally, the cooling oil will enter the system along with the compressed air, polluting the compressed air and causing serious consequences to the system.
Therefore, in order to prevent the generation of condensed water, the temperature in the compression chamber cannot be too low and must be greater than the condensation temperature. For example, an air compressor with a discharge pressure of 11 bar (A) has a condensation temperature of 68 ° C. When the temperature inside the compression chamber is lower than 68 ° C, condensed water will be precipitated. Therefore, the exhaust gas temperature of the oil-injected screw air compressor cannot be too low, that is, the application of the isothermal compression is limited in the oil-injected screw machine due to the problem of condensed water.
