Liquid ring vacuum pumps normally operate with water as the operating medium. An eccentrically installed impeller rotates in the casing partly filled with liquid. By the rotational movement of the impeller and the resulting centrifugal force the liquid within the cylinder forms the so-called liquid ring.
Gas is conveyed in the spaces between the single vanes and the liquid ring. Due to the eccentric installation of the impeller the spaces enlarge and the process gas is sucked in through the suction slot.
As the impeller further rotates, the spaces are reduced, so that the gas is compressed and discharged through the discharge slot. The vacuum pump can be operated with water recirculation, open or closed loop circuit.