A pump formed in accordance with the present invention is of conventional construction from the standpoint that it includes a housing defining a pumping chamber having an axially opening suction inlet and a radially opening discharge outlet; an impeller mounting for rotation within the pumping chamber by a drive shaft, which is aligned with the suction inlet and arranged to extend rearwardly of the impeller through an opening formed in a rear wall of the pumping chamber; and a gas removal system for removing gas tending to collect within the pumping chamber rearwardly of the impeller. More specifically, the impeller includes a shroud extending radially of the drive shaft and having flow openings extending between front and rear surfaces thereof; pumping vanes carried by the front surface of the shroud for pumping liquid between the suction inlet and discharge outlet; and pump-out vanes carried by the rear surface of the shroud for pumping liquid passing rearwardly of the impeller through the flow openings for discharge through the discharge outlet. The gas removal system includes a vent chamber opening through the rear wall of the pumping chamber annularly of the drive shaft, a vacuum pump, a gas vent conduit connecting the vent chamber to the vacuum pump, and a gas flow control valve arranged in the gas discharge conduit for varying the pressure within the vent chamber.BALANCING VALVES Where the pump is intended to pump liquids from which gas is difficult to extract by reliance only upon the centrifugal action of the impeller, such as for the case of relatively high consistency fibrous suspension and relatively homogeneous liquid-gas mixtures, a fluidizer or centrifuge may be fitted on the drive shaft forwardly of the impeller to aid in separation of gas from the suspension or mixture under centrifugal action and the collection thereof in a core or "gas bubble" forwardly of the eye of the impeller.

In accordance with the present invention, an impeller to be employed in a centrifugal pump is fitted with a repeller shroud mounted to extend radially from the hub of an impeller and cooperates with its shroud and pump-out vanes to define radially extending flow paths communicating with flow openings extending through the impeller shroud for purposes of imparting a well defined radial flow component to gas and liquid passing rearwardly of the impeller through the flow openings. Water Power Control ValvesThe repeller shroud may be fitted with rearwardly extending repeller vanes adapted to project into an annular chamber formed in a rear wall of a pumping chamber of the pump concentrically outwardly of its vent chamber.

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2011-12-18

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