Patent ID: 11904155
Assignee: STAR BP, INC.
Field: Medical technology (Instruments)
Classification: CPC A | IPC A

Claim 15:
16. A heart assist apparatus, comprising:
a pump housing having a first end and a second end;
a rotor retained within said pump housing;
said rotor comprising a shaft with an outer surface and an impeller extending from the shaft at a first location on the outer surface at a proximal end of said rotor at the first end of said pump housing;
said outer surface of said rotor comprising an outer bearing surface at a second location on the shaft with a radial bearing at or adjacent to the outer bearing surface comprising a radial journal bearing surface;
an axial bearing comprising a hemispherical surface or conical surface disposed axially adjacent a leakage inlet of said pump housing at a distal end of said rotor at the second end of said pump housing and having a plurality of grooves configured for promoting blood flow into a leakage flow path from the leakage inlet;
said pump housing comprising one or more cylindrical bores configured to define a pumping chamber and an inner bearing surface within the pump housing and a radial port disposed between the pumping chamber and the inner bearing surface, with said radial port configured to provide at least a radial component with respect to direction of flow;
wherein said impeller is configured for rotating within the pumping chamber upon actuation of the rotor to draw a first flow of blood inward from the radial port into the pumping chamber;
wherein rotation of the impeller draws a second flow of blood through an axial port, as the leakage inlet, disposed at the second end of the pump housing, into the pumping chamber along the length of the inner bearing surface through a leakage flow path in fluid communication with an annular clearance between the inner bearing surface and outer bearing surface;
wherein said inner bearing surface of the pump housing is closely fitted to said outer bearing surface of said shaft to form the annular clearance there between such that during actuation of the rotor the inner bearing surface and outer bearing surface form a hydrodynamic journal bearing;
wherein the apparatus is configured so that the flow of blood may be reversed by reversing the direction of the impeller wherein blood is input into said pumping chamber and output through said radial ports;
wherein said rotor comprises one or more rotor magnets located within the bearing surface of said shaft of said rotor;
wherein the pump housing comprises a motor stator having a coil positioned opposite said one or more rotor magnets from the annular clearance; and
wherein actuation of the rotor is affected by electrical current flow through the motor stator to generate a magnetic flux field that extends across the leakage flow path to displace the one or more rotor magnets to achieve rotational motion of said rotor.