The liquid ring pump (Fig. 2-13) is and unusual pump in that it is not used for conventional water pumping applications.However, as a vacuum pump-even as a low-pressure gas or air compressor, it has numerous advantages.It has only one moving part, a balanced rotor.All functions of mechanical pistons or vanes are actually performed by a rotating band of liquid compressant.While power to induce rotation is transmitted by the rotor, this ring of liquid follows a path around the cylindrical interior of the pump body.The rotor axis is offset from the body axis.It is a cross between a dynamic and a positive displacement pump.As the figure shows, liquid compressant almost fills, then almost empties, each rotor chamber during a single revolution.That sets up the piston action.Inlet connections and pressure discharge connections are separated by ported openings in the stationary inner cones.