Oil Sealed Rotary Vane Pumps operate according to the rotary vane principle. The rotor is eccentrically positioned in the cylinder and has the slots for vane sliding. The centrifugal forces when rotates push the vanes towards wall of the cylinder through the slots of the rotor. The gas will be sucked in through a built-in anti suck back valve that prevents the pump from rotating backward at standstill, and goes into the cylinder. The gas will be compressed and pushed out through the exhaust opening located between the pumps housing and oil sump. The oil will be fed into the pump module from the oil sump for sealing and lubrication by differential pressure between pump module and oil sump, and will be collected through the oil separator in the upper part of oil sump. The oil will be dropped to the lower part of oil sump though the check valve or will be drawn to the pump module for re-circulation.