The oil-free screw compressor element
No oil means that there is no essential oil for sealing the rotors and for cooling the Oil-free Screw Air Compressor 
compressed surroundings, elements and rotors. … The component is certainly cooled by cooling water that flows through particular pockets in the element casing.
In a lubricated screw compressor, the lubricant will come in direct in touch with the compressor inlet air and compressed air. … The essential oil contains anti-oxidants to attempt to reduce the breakdown of the lubrication properties due to internal conditions.