These are oil-immersed, Rotary vane type pumps. The rotor, with two spring loaded vanes is mounted ecentric in the stator body, as the rotor rotates, the when’s sweep the crecente shape air spacer twice in each revolution. There is in built non-return valve which prevents backflow of air. Manufactured from graded material/ all moving parts are precisely machined/ ground and assembled with close tolerances. this results in increased efficiency and long trouble free operating life