Abstract: A first head of a liquid ring pump has an inlet, an outlet, a shaft receiving aperture extending there through, and an internal end. The internal end includes a boss with a side wall. The boss is received by a pump body. An interstage manifold is removeably coupled to the pump without being integral with or connected to the pump body. An o-ring can be located between a side wall of the boss and an internal side wall of the body.

Abstract: Liquid ring pumps, of the type having a port structure that extends into an annular recess in an end of the rotor, have several parts that are designed so that they can be used to make pumps having either relatively demanding service requirements or substantially less demanding service requirements. Some of these parts can be substantially exactly the same in both final pump configurations. Others of these parts may be castings that differ substantially only in some subsequent machining in order to adapt them for each final pump configuration. Some of the final pump configurations have more compact mechanical seal structures and/or improved structures for supplying liquid to the seal structures.

Abstract: A two-stage liquid ring pump has an interstage structure which promotes separation of the gas and liquid discharged from the first stage. The second stage has separate gas and liquid inlets for respectively admitting the separated gas and liquid to the second stage. This avoids any possible choking of the second stage gas inlet by liquid, thereby improving the performance of the pump.

Abstract: To decrease gas leakage across the cantilevered axial end of the hub of a liquid ring pump rotor which has a central recess in that end of the hub, the adjacent port structure is provided with a protrusion which extends axially part way into the recess in the rotor hub. A relatively small clearance is provided between the radially outer surface of the protrusion and the radially adjacent inner surface of the recess. This clearance is filled with liquid and thereby increases the area of the seal at the adjacent axial end of the rotor hub.