The 
general mechanism of an air compressor is a piston or rotary element (e.g. rotary screw or vane) that draws in atmosphere, which is compressed right into a storage tank. Naturally, since the piston or rotary element needs to move regularly and smoothly because of this to function, it generally must be lubricated.
In a 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 temperature and keep maintaining air compression efficiency.
Oil-free of charge air compressors also use a piston or rotary element, however they bypass the lubrication problem by coating the compression component with a pre-lubricating material like Teflon. Some oil-free compressors could also use water in place of oil for the lubricating and cooling procedure. These alternate materials shield the pump and Water Lubricated Air Compressor invite the mechanism to go smoothly with no need for any oil-centered or synthetic lubrication.