Liquid Ring Vacuum Pump

When the impeller rotates in the casing filled up with one half of water,the water is then splashed and begins to flow along the inner wall of the casing because of the centrifugal force and forms a liquid (water) ring. As the center of the impeller and shaft is eccentric against the center of the casing , it makes an air chamber of a crescent form inside the liquid ring.

Since this crescent shaped air chamber expands at the right and contracts at the left, it works to compress the air . Therefore,providing the suction port at the expanding side and the discharge port at the contracting side makes the air drawn and exhausted continuously.