Integrated centrifugal pump and motor

Claim 1

A centrifugal pump comprising: a housing having an internal chamber with inlet and discharge ports; an impeller supported in said chamber for rotation about an axis, the impeller having a hub section having an axis about which it may rotate to pump a working fluid, the impeller having a central opening; first and second disk shaped shrouds supported from said tub section, at least one of said shrouds containing permanent magnets; and a plurality of pumping channels defined by a plurality of impeller blades projecting outwardly from the hub section in a common plane between said first and second shrouds so as to rotate in a common plane normal to said axis; a motor stator coil for rotatably driving said impeller, the stator coil being disposed adjacent said shrouds so as to form a gap between the stator coil and the shroud for receiving a small quantity of pumped working fluid, the stator coil further having a central opening therein, the working fluid passing through the stator coil central opening and through the impeller central opening; a means for axial hydrodynamic balancing of said impeller, the means comprising a ring disposed in said gap for restricting the flow of the small quantity of pumped working fluid; a means for inducing flow of a working fluid toward the pumping channels from opposite directions, the means for inducing flow of a working fluid to the pumping channels comprising an opening between the hub section and each shroud and an inducer in the opening, the inducer comprising a pumping member which is separate from the impeller; and a recirculation passage adjacent each inducer.