Oil-free air compressor is a miniature reciprocating piston compressor. When the motor single-shaft drives the compressor crankshaft to rotate, through the transmission of the connecting rod, the piston with self-lubricating without adding any lubricant reciprocates. The working volume composed of the inner wall of the cylinder, the cylinder head and the top surface of the piston changes periodically.

When the piston of the piston compressor and the cylinder head start to move, the working volume of the cylinder increases gradually. At this time, the gas is pushed into the intake valve along the intake pipe and enters the cylinder until the working volume z is maximized, and the intake valve is closed; the piston moves backward, the working volume in the cylinder decreases, and the pressure in the cylinder increases. When the pressure in the cylinder reaches and is slightly higher than the exhaust pressure, the exhaust valve opens and the gas is discharged from the cylinder until the piston moves to the limit position and the exhaust valve closes. The above process is repeated, and when the piston moves backwards again, the piston moves again.

That is to say, the crankshaft of the piston-type oil-free air compressor rotates once, the piston reciprocates once, and the suction, pressure and exhaust are sequentially realized in the cylinder, that is, the working cycle is completed. The single-shaft double-cylinder structure design is adopted, so that when the rated speed of the compressor is constant, the gas flow can reach twice that of the single-cylinder, and the vibration and noise can be effectively suppressed.

The working principle of the whole machine:

When the motor is running, the air enters the compressor through the air filter, the compressor compresses the air, compresses the air through the airflow pipe, opens the one-way valve and enters the air storage tank, and the pointer of the pressure gauge rises to 8Bar accordingly. When the pressure switch sensing channel pressure exceeds 8Bar, the motor will automatically shut down, and the solenoid valve will discharge the air pressure at the head of the compressor to 0. At this time, the air switch pressure shows that the air pressure in the air storage tank is still 8Bar, and the gas is exhausted by the ball valve to drive the connecting equipment to work. After the air pressure in the air storage tank drops, the pressure switch is automatically opened by induction, and the compressor starts to work again.

The above is the working principle of oil-free air compressor, for reference only. There are two types of oil-free screw air compressors, one is oil-free water lubrication, and the other is dry grinding. The working principles of the two are also completely different.