The overall Water Lubricated Air Compressor mechanism of an air compressor is a piston or rotary element (e.g. rotary screw or vane) that draws in air, which is compressed into a storage container. Naturally, because the piston or rotary element needs to move consistently and smoothly for this to function, it generally needs to be lubricated.

In a lubricated air compressor, there is lubricating oil which keeps the piston or rotary element running well without damaging the mechanism. The lubricant also helps to dissipate temperature and maintain 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 materials like Teflon. Some oil-free compressors could also use water instead of essential oil for the lubricating and cooling process. These alternate materials secure the pump and invite the mechanism to go smoothly with no need for any oil-centered or synthetic lubrication.