Water ring vacuum pumps in various construction and consist of a dynamically balanced impeller with multivanes and is eccentrically mounted in a casing, rotates at motor prm and imparts centrifugal force to water introduced in a casing to form a ring against the main casing wall. The pockets increasing with angular displacement are connected to the outlet part. The water ring thus acts a sealing as well as cooling agent. They find application in distillation, condenser exhausting, moisture extracting, condenser exhausting, moisture extracting, solvent recovery, pneumatic conveying, dredging installations and so on.