Oil-free rotary screw compressor - External gears ...

Oil-free rotary screw compressor - External gears synchronize the position of the counter-rotating screw elements, and, because the rotors do not come in contact and create friction, no lubrication is needed within the compression chamber. As a result, the compressed air is oil-free. Precision engineering within the housing minimizes pressure leakage (and drops) from the pressure side to the inlet. And because the internal pressure ratio is limited by differences in air temperature between the inlet and discharge ports, oil-free screw compressors are frequently built with several stages and inter-stage cooling to maximize the pressure reach. The gearbox driving the mechanism does contain lubricants; oil-free refers to the compression chamber itself, and the delivered air is free of foreign contaminants beyond those found inherently in the air that passes through the intake.