The oil-free screw compressor element
No oil implies that there 
is absolutely no essential oil for sealing the rotors and for cooling the compressed air flow, components and rotors. … The Oil-free Screw Air Compressor china component is certainly cooled by cooling drinking water that flows through special pockets in the component casing.
In a lubricated screw compressor, the lubricant comes in direct in touch with the compressor inlet air and compressed air. … The essential oil contains anti-oxidants to try to reduce the breakdown of the lubrication properties because of internal conditions.