What is the factor of actual displacement of screw air compressor?Theoretically speaking, the displacement of screw compressor depends on the volume of teeth, number of teeth and rotation speed.The intertooth volume is determined by the geometric dimensions of the rotor.In practice, there are four possible reasons why the actual displacement of screw air compressor is less than the theoretical displacement:
1) leakage.There is no contact between the rotors or between the rotors and the housing during operation, and a certain gap is maintained, so gas leakage will occur.When the air after the pressure increases leaks into the suction pipe and the suction groove through the gap, the exhaust volume will be reduced.In order to reduce the amount of leakage, the tooth top of the driven rotor has sealing teeth, the tooth root of the active rotor has a sealing groove, and the end face is also processed with ring or strip sealing teeth.If these sealing lines wear, will increase the amount of leakage, reduce the amount of exhaust;
2) inhale.Screw type air compressor is volumetric compressor, suction volume unchanged.When the suction temperature rises, or the suction line resistance is too large and the suction pressure decreases, the density of the gas decreases, and the mass discharge of the gas will be reduced accordingly.
3) cooling effect.The temperature of the gas will increase during the compression process, and the temperature of the rotor and the housing will increase accordingly. Therefore, during the suction process, the gas will be heated by the rotor and the housing and expand, so the suction volume will be reduced accordingly.The rotor of screw type air compressor is cooled by oil, and the shell is cooled by water, one of its purposes is to reduce its temperature.When the cooling effect is not good, the temperature will increase, the exhaust volume will be reduced;
4) speed.The displacement of screw compressor is proportional to the speed.And the speed often with the grid voltage, frequency and change.When the voltage is lowered (for asynchronous motors) or the frequency is lowered, the speed will drop, reducing the air volume.