Centrifugal pump with variable impeller

Claim 2

In a radial flow centrifugal pump, said pump having a drive shaft and a housing which defines an axial inlet and a collector for receiving a fluid being pumped, means for varying the pump capacity comprising: a driver impeller coupled to the pump drive shaft, said driver impeller including a base member having a plurality of vane defining projections on a first face thereof; a driven impeller, said driven impeller including a base member having a plurality of vane defining projections on a first face thereof, said driven impeller being positioned with the vanes thereof facing and engaging the vanes on said driver impeller whereby said impellers define multiple cascades of flow channels which discharge into the common pump collector; and means including an inducer spring positioned within the assembly defined by said driver and driven impellers for varying the axial relationship between said impellers, said spring inducing flow into said flow channels and cooperating with said driver and driven impellers to establish a preselected impeller flow area at a given back pressure.

Claim 3

The apparatus of claim 1 further comprising: seal means for hydraulically isolating the pump inlet and collector regardless of impeller assembly width whereby the pressure differential across the impeller assembly is balanced against the inducer spring and the flow areas within the impeller assembly are sensitive to the pump back pressure.

Claim 4

In a radial flow centrifugal pump, said pump having a drive shaft and a housing which defines an axial inlet and a collector for receiving fluid being pumped, means for varying the pump capacity comprising: a driver impeller coupled to the pump drive shaft, said driver impeller including a disc-shaped base member having a plurality of arcuate projections on one face thereof, said projections defining impeller vanes which increase in width from the inlet toward the collector; a driven impeller, said driven impeller including a discshaped base member having a plurality of arcuate projections on one face thereof, said projections defining impeller vanes which increase in width from the inlet toward the collector, said driven impeller being the mirror image of said driver impeller and being positioned with the vanes thereof facing and engaging the vanes on said driver impeller, said engaged impeller vanes cooperating to define pairs of diverging circumferentially offset flow channels whereby said impellers define multiple cascades of flow channels which discharge into the common pump collector; and self-compensating hubless flow inducer means at least partly positioned within the assembly defined by said driver and driven impellers, said flow inducer means varying the axial relationship between said driver and driven impellers to vary the depth of the impeller flow channels.

Claim 5

In a radial flow centrifugal pump, said pump having a drive shaft and a housing which defines an axial inlet and a collector for receiving fluid being pumped, means for varying the pump capacity comprising: a driver impeller coupled to the pump drive shaft, said driver impeller including a disc-shaped base member having a plurality of arcuate projections on one face thereof, said projections defining impeller vanes which increase in width from the inlet toward the collector; a driven impeller, said driven impeller including a discshaped base member having a plurality of arcuate projections on one face thereof, said projections defining impeller vanes which increase in width from the inlet toward the collector, said driven impeller being the mirror image of said driver impeller and being positioned with the vanes thereof facing and engaging the vanes on said driver impeller, said engaged impeller vanes cooperating to define pairs of diverging circumferentially offset flow channels whereby said impellers define multiple cascades of flow channels which discharge into the common pump collector; and self-compensating hubless flow inducer means at least partly positioned within the assembly defined by said driver and driven impellers, said flow inducer means varying the axial relationship between said driver and driven impellers to vary the depth of the impeller flow channels.

Claim 6

The apparatus of claim 3 wherein said hubless flow inducer means comprises: an inducer spring, said spring urging said driver and driven impellers toward one another.

Claim 7

The apparatus of claim 4 further comprising: seal means for fluidically isolating the pump inlet and collector regardless of the relative position of said impellers whereby the pressure differential across the impeller assembly will oppose said inducer spring.

Claim 8

The apparatus of claim 3 wherein said inducer means comprises: an inducer spring, said spring including flow into the impeller and cooperating with said driver and driven impellers to establish a preselected impeller flow area at a given pump back pressure.

Claim 9

The apparatus of claim 3 wherein said impeller flow channels are of constant arc from the inlet to the discharge ends thereof, the width of said vanes on each impeller approximating the width of the channels defined by the vanes of the mating impeller.