Abstract: A liquid-ring pump according to the invention for use as a vacuum pump, e.g. for the aspiration of centrifugal pumps, and for use in the transport of fluids, e.g. mixtures of liquids and gases or solid particles, is of the type where the distance between the internal surface (17) of the pump housing and the rotor (10) varies. Seen in section, the surface is divided into two identical, reverse-image sectors, in relation to which the rotor (10) is disposed in a symmetrical manner. In the transition area between the two sectors the internal surface (17) is provided with a substantially flat surface (44) stretching tangentially in relation to the periphery of the rotor (10). Thereby cavitiation problems are reduced.

Abstract: A liquid ring pump including a helically bladed rotor 2 eccentrically mounted in an elongated pump casing 1 and including a hub 3, a suction inlet 18 and a discharge outlet 19 at respective ends of the pump casing 1. The open space between the bladings ends at the inlet are closed by a preferably circular plate 26 and access to the space between the buildings is given only through one or more openings 27 in the plate 26. This results in a minimizing of the power loss.Paddles 28 could be attached to the plate 26 and there could be a plate 31 at the discharge end as well. Further the holes 27 could be arranged in the hub 3, and the end of the rotor at the inlet end could be located in a cavity 32 in the end wall 10.