Baxter International Inc.

Dieter Westphal

Helmut Reul

Guenter Rau

A magnetically-driven centrifugal blood pump includes a housing and an impeller mounted for rotation within. The impeller includes a generally disk-shaped base plate and a plurality of curvilinear vanes extending axially upward therefrom. The vanes project radially outward from the base plate approximately one-third of their curvilinear length. The housing includes a rear wall spaced from the impeller base plate across a constant gap, with a sloped transition wall surrounding the rear wall and joining it to a peripheral wall. A tangential outlet is provided in the peripheral wall. A front wall extends inward from the peripheral wall with a slight conicity to an axial inlet. The vanes each have a front edge which slopes away from the front wall in the radially outward direction to provide a widening gap therebetween. The vanes have inner ends which together define a vane-free inner region below and slightly larger than the inlet. The curvature of each vane changes along its length, and a tangent angle progresses from the inner end to the outer end according to a preferred formula. Desirably, the impeller includes a pair of low magnetic retentivity plates, such as steel, which are driven by an external drive which sets up a rotating magnetic field.

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Woerthsee, Germany

Dieter Westphal