The overall mechanism of an air compressor is a piston or rotary component (e.g. rotary screw or vane) that allures air flow, which is compressed right into a storage container. Naturally, because the piston or rotary component needs to move consistently and smoothly because of this to work, it generally must be lubricated.
In a Water Lubricated Air Compressor lubricated air compressor, there is lubricating oil which will keep the piston or rotary element running well without damaging the system. The lubricant also helps to dissipate high temperature and keep maintaining air compression efficiency.
Oil-free air compressors also use a piston or rotary element, but they bypass the lubrication problem by coating the compression element with a pre-lubricating materials like Teflon. Some oil-free compressors could also use water in place of oil for the lubricating and cooling process. These alternate materials protect the pump and allow the mechanism to move smoothly without the need for any oil-centered or synthetic lubrication.