Chinese Journal of Mechanical Engineering

Table 7 Analysis of energy flow in a pneumatic system

Components	Absolute pressure (MPa)	Volume flow-rate (dm³/s)	Input power (kW)	Output power (kW)	Efficiency⁽¹⁾	Remarks
Compressor	Export: 0.9	200	73.75	44.25⁽²⁾	60%	Screw type, rated power: 75 kW
Refrigeration dryer⁽³⁾	0.9 → 0.9	200 → 200	44.25	44.25	K_dy = 0.97	Power consumption: 2.28 kW
Filter	0.9 → 0.873	200 → 200	44.25	43.64	98%	–
Pipe line, connector, control valve, etc.	0.873 → 0.8	200 → 160	43.64	33.49	76.8%	Leakage (20%): 40 dm³/s, pressure drop along the way (8.36%): 0.073 MPa
Cylinder	Intake: 0.8	160	33.49	8.37	25%	Power of speed control (22%): 7.369 kW, pneumatic expansion power (53%): 17.75 kW, pneumatic transmission power (47%): 15.742 kW

⁽¹⁾Total efficiency is equal to product of efficiencies of all components
⁽²⁾Output power of compressor here is available power
⁽³⁾Because pipe line between compressor, refrigeration dryer and filter is relatively short, pressure drop along the way and leak can be neglected, effect summation of which is considered in pipe line