The oil-free screw compressor element
No oil means that there is absolutely no essential oil for sealing the rotors and for Oil-free Screw Air Compressor cooling the compressed air, elements and rotors. … The component is certainly cooled by cooling drinking water that flows through unique pockets in 
the component casing.
In a lubricated screw compressor, the lubricant comes in direct in contact with the compressor inlet air and compressed air. … The essential oil contains anti-oxidants to attempt to reduce the break down of the lubrication properties because of internal conditions.