Swam Liquid Ring Vacuum Compressors and Pumps are rotary machines in which liquid is made to act as a piston. This liquid is generally water for most of the applications. Hence these are known as Water Ring. A balanced rotor with fixed radial blades having slight curvature at the tips and a hollow hub revolves in a circular casing containing the liquid. The axis of rotor is placed eccentric with the axis of casing. At the operating speed the liquid rotates in the casing forming a circular hollow ring whose internal surface is at varying distance from the axis of rotor. Starting at a position in which the
liquid ring is nearest to the rotor axis and completely fills the space between the two adjacent rotor blades the moving liquid ring now acts as piston on its suction stroke. This continues till the rotor chamber moves to the next position.

During this travel all the chambers formed by the blades are connected to the inlet branch of the pump through specially designed ports in the cones and end covers (heads). While traveling between these positions the chamber formed by any two adjacent blades decrease in volume as the liquid ring is moving towards the center acting as piston on its compression stroke.