Abstract: In liquid ring gas pumps of the type having a rotor rotatably mounted in a stationary housing for forming a quantity of pumping liquid into a recirculating ring inside the housing, fluid friction loss between the liquid and the housing is reduced by shaping the surface of the housing which is in contact with the liquid ring radially outside the rotor so as to minimize or at least substantially reduce the area of that surface.

Abstract: In liquid ring pumps having rotating lobe liners supported by a bearing fluid in an annular clearance between the liner and the surrounding housing, the housing has at least one substantially annular channel formed in the housing for distributing the bearing fluid to a plurality of circumferentially spaced apertures extending through the housing from the channel to the clearance.

Abstract: A liquid ring pump with a conical or cylindrical port member has a vent-recirculation port in the port member in addition to the conventional intake and discharge ports. The vent-recirculation port communicates with the compression zone of the pump and is connected to a reservoir of pumping liquid maintained in the discharge portion of the pump head. When the pump is operating at relatively low compression ratios, the vent-recirculation port acts as a vent to prevent overcompression of the gas in the pump. At relatively high compression ratios, the vent-recirculation port recirculates pumping liquid from the reservoir, thereby increasing the maximum attainable compression ratio.