Selection steps: first determine the working pressure, and then set the corresponding displacement, and finally the motor power:
1. Discharge Pressure:
The customer's use of the pressure, pipeline resistance loss and supporting equipment, the sum of the pressure drop, as the selection of the compressor rated discharge pressure of the lower limit of the Pmin, the selection of the working pressure for the Pmin + 0.5bar can be.
Assuming that the lowest air pressure for the customer is Pmin=6bar, then the working pressure only needs to be 6.5bar, no need to choose 8bar.
Because of the stability of the air pressure of the inverter screw machine: Because of the inverter screw machine utilizes the characteristics of the frequency converter's stepless speed regulation, through the controller or the inverter's internal PID regulator, it can realize the rapid adjustment and control of the pressure, and can keep the pressure in a constant state. Maintained in a constant state. There is no need to consider the upper and lower limit pressure difference as in the case of industrial frequency screw machines.
Generally, customers are advised to choose a larger diameter of the pipeline to minimize resistance loss and reduce energy consumption in long-term operation. The higher the exhaust pressure of the compressor, the more energy consumption, so do not choose a compressor with too high exhaust pressure; choose a compressor with too high exhaust pressure,
and then reduce the pressure through the regulator, it is absolutely wasteful.
2. exhaust volume:
A, the maximum exhaust volume selection:
① first understand all the volumetric flow of the gas equipment, the total flow multiplied by 1.2 (i.e., amplified by 20% margin);
② new projects on the ground can be based on the flow values provided by the design institute for selection;
3 to the gas equipment suppliers to understand the volumetric flow parameters for selection;
3 to the gas equipment suppliers to understand the volumetric flow of the gas equipment. Volume flow parameters for selection;
④ air compressor station renovation can refer to the original parameters combined with the actual use of gas selection;
B, the long-term use of gas selection
The site should be in the air compressor exhaust volume of 60% to 85% of the volume of air, i.e., most of the time the machine should be in the 30HZ ~ 45HZ operation.
C, the selection of exhaust volume should pay attention to should not be too large and too small
★ Selection of exhaust volume is too large (customer air consumption for a long time less than 30% of the rated exhaust volume)
1) motor long time in the low-frequency operation, easy to high temperature.
(2) The acquisition cost of selecting a large displacement compressor is higher.
★ Selected displacement is too small (customer gas consumption for a long time more than 90% of the rated displacement)
(1) the customer will respond to the exhaust volume is not enough
(2) the motor long time full-load operation, inverter frequency conversion effect is not good, at the same time, the motor is easy to high temperature
In this case the selection of the industrial frequency screw can be
3, the choice of motor power
According to the selected working pressure and exhaust volume, select the matching motor power
4, special circumstances to deal with the program: