Requirements for selecting air compressors

The selection of air compressor is mainly based on the working pressure and flow of the pneumatic system.

The working pressure of the air source should be about 20% higher than the working pressure in the pneumatic system, because the loss along the air supply pipeline and the local loss should be considered. If the working pressure requirements in some places in the system are lower, a pressure reducing valve can be used to supply air. The rated exhaust pressure of the air compressor is divided into low pressure (0.71.0MPa), medium pressure (1.010MPa), high pressure (10100MPa) and ultra-high pressure (above 100MPa), which can be selected according to actual needs. The common use pressure is generally 0.7-1.25.

First, select the type of air compressor according to the characteristics of the air compressor. Then, determine the output pressure pc and suction flow qc of the air compressor according to the two parameters of working pressure and flow required by the pneumatic system, and select the model of the air compressor.

(1) Output pressure of air compressor pc

pc=p plus∑△p

pc: output pressure of air compressor

p: Operating pressure of pneumatic actuator

∑△p: Total pressure loss of pneumatic system.

In general, ∑△p=0.150.2MPa.

(2) Air compressor suction flow qc

Without gas tank, qb=qmax

Assume gas tank, qb=qsa

qb: Flow rate provided by the pneumatic system

qmax: air consumption of the pneumatic system

qsa: average air consumption of the pneumatic system

Air compressor suction flow, qc=kqb

qc: air compressor suction flow

k: Correction coefficient. Mainly consider the leakage of pneumatic components, pipe joints, etc., the estimation error of pneumatic system gas consumption, the utilization rate of multiple pneumatic equipment used at different times, and the possibility of adding new pneumatic equipment. Generally, k=1.52.0.

(3) Air compressor power P

p=(n plus 1) kp1qc (pc\/p1) { (k-1)\/(n plus 1) k-1}\/(k-1) 0.06