Calculation of displacement of piston compressor of medium and high pressure compressor

The displacement of piston compressor usually refers to the volume of exhaust gas measured at the exhaust end of compressor in unit time, which is converted into the value under the suction conditions (pressure, temperature, humidity, etc.) of the first stage of compressor. The usual unit is m3/min or m3/h .. However, in the conversion, the following two points should be noted:

1) for actual gas, the influence of gas compression factor should be taken into account when converting;

2) For the gas containing water vapor, after compression, the partial pressure of water vapor also increases, and the gas may condense out moisture in the intercooler and be separated in the liquid-gas separator.

When making rough estimation, it is considered as dry gas. According to the gas volume value Qd(m3/min) measured at the last stage, the displacement Q0(m3/min) is the gas pressure corresponding to Pa--Qd in the formula, MPa；; Td--Qd corresponding gas temperature, k; P1-- gas pressure of the first stage in I: 1 state, MPa；; T1-- gas temperature at the inlet of the first stage, k.

For small piston compressors, the volumetric method is often used to calculate the displacement. The displacement of large compressor is measured by flowmeter. When testing with air, the discharged pressurized air is often directly discharged into the atmosphere through the flowmeter. At this time, the displacement of the compressor can be directly calculated according to the calculation formula of the flowmeter, and then the precipitated water is added.