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A blood pump comprises a pump housing; a rotor positioned in the housing and comprising an impeller having a hydrodynamic surface for pumping blood; and a motor including a plurality of magnets carried by the impeller, plus a rotor stator, including an electrically conductive coil located adjacent t

A blood pump comprises a pump housing; a rotor positioned in the housing and comprising an impeller having a hydrodynamic surface for pumping blood; and a motor including a plurality of magnets carried by the impeller, plus a rotor stator, including an electrically conductive coil located adjacent to or within the housing. The impeller comprises radially outwardly extending, bladelike projections that define generally longitudinally extending spaces between the projections. The shape of the projections and the spaces therebetween tend to drive blood in the spaces in an axial direction as the impeller is rotated. The spaces collectively have a total width along most of their lengths at the radial periphery of the rotor, that is substantially equal to or less than the collective width of the projections along most of their lengths at the radial periphery. Thus, the bladelike projections are thicker, achieving significant advantages.

대표청구항 ▼

That which is claimed is: 1. An axial flow blood pump, comprising: a pump housing; a rotor for effecting axial blood flow through the axial flow pump, said rotor being positioned in said housing and comprising an impeller having a hydrodynamic surface for pumping blood; a motor including a pluralit

That which is claimed is: 1. An axial flow blood pump, comprising: a pump housing; a rotor for effecting axial blood flow through the axial flow pump, said rotor being positioned in said housing and comprising an impeller having a hydrodynamic surface for pumping blood; a motor including a plurality of magnetic poles carried by the impeller, and a rotor stator including an electrically conductive coil located adjacent to or within said housing; and said rotor comprising wide, radially outwardly extending, bladelike projections that define generally longitudinally extending spaces between said projections, said projections being shaped to form curves in said spaces of a shape tending to drive blood in said spaces in an axial direction as the impeller is rotated, said spaces collectively having a total width at the radial periphery of the rotor, that is substantially equal to or less than the collective total width of said projections along most of their lengths at said radial periphery; said projections having radially outer faces carrying hydrodynamic bearings, said hydrodynamic bearings comprising curved surfaces that are recessed into said outer faces of said projections to form recessed surfaces that are tapered in a gradual manner, the most recessed end forming a leading edge of rotation, whereby as the rotor rotates the hydrodynamic bearings scoop blood into a cross-sectional recessed area that decreases going from a leading portion of the projection to a trailing portion thereby pressurizing the blood. 2. The blood pump of claim 1 in which said rotor has a length greater than its width. 3. The blood pump of claim 2 in which said hydrodynamic bearings each define a bearing surface with shroud walls at sides of said bearing surface transverse to the rotation axis of the rotor. 4. The blood pump of claim 2 in which at least one magnetic bearing system is also provided to help to position said rotor. 5. The blood pump of claim 4 in which said at least one magnetic bearing system comprises permanent magnets mounted in said bladelike projections, the motor being of the radial flux gap design, whereby, magnetic forces hold the rotor in position. 6. The blood pump of claim 5 in which said permanent magnets are covered with peripheral cover caps. 7. The blood pump of claim 6 in which said peripheral cover caps define weight reducing open spaces. 8. The blood pump of claim 1 in which the motor comprises a separate, hermetically sealed motor that slides over a tubular housing into position, and is secured thereto. 9. The blood pump of claim 1 in which said housing is cylindrical. 10. The blood pump of claim 4 in which said at least one magnetic bearing system comprises permanent magnets mounted in said projections. 11. The blood pump of claim 1 in which said housing is made from biocompatible titanium or ceramic. 12. The blood pump of claim 1 which comprises a plurality of said rotors positioned within said pump housing, and each engaged by one of a plurality of said motors, in series flow, for increased pumping pressure capacity. 13. The blood pump of claim 1 in which said projections define said longitudinally extending spaces with sidewalls having transverse sections that mostly have generally parallel sides. 14. An axial flow blood pump comprising: a pump housing; a rotor for effecting axial blood flow through the axial flow pump, said rotor being positioned at said housing and comprising an impeller having a hydrodynamic surface for pumping blood; a motor including a plurality of magnets carried by the impeller and a stator including an electrically conductive coil located adjacent to or within said housing; and said rotor comprising wide, radially outwardly extending, bladelike projections that define generally longitudinally extending spaces between said projections, said projections being shaped to form curves in said spaces of a shape tending to drive blood in said spaces in an axial direction as the impeller is rotated, said rotor also having a length greater than its width, said longitudinally extending spaces collectively having a total width at the radial periphery of the rotor that is substantially equal to or less than the collective total width of said projections at said radial periphery; said projections having radially outer faces which carry hydrodynamic bearings; and in which at least most of the volume of each of said projections is magnetized to permit rotation of said rotor by the motor; said hydrodynamic bearings comprising curved surfaces that are recessed into said outer faces of said projections to form recessed surfaces that are tapered in a gradual manner, the most recessed end forming a leading edge of rotation, whereby as the rotor rotates the hydrodynamic bearings scoop blood into a cross-sectional recessed area that decreases going from a leading portion of the projection to a trailing portion thereby pressurizing the blood. 15. The blood pump of claim 14 in which the motor comprises a separate, hermetically sealed motor that slides over said pump housing into position, and is secured thereto, said housing being cylindrical. 16. The blood pump of claim 15 in which said housing is made from biocompatible titanium alloy or ceramic. 17. The blood pump of claim 14 which comprises a plurality of said rotors positioned within said pump housing, and each being engaged by one of a plurality of said motors, in series flow, for increasing pumping pressure capacity. 18. The blood pump of claim 14 in which said projections defining said longitudinally extending spaces have side walls with transverse sections that mostly have generally parallel sides. 19. The blood pump of claim 14 in which said rotor carries a conformal polymer coating to prevent oxidation by forming a hermetic seal around said rotor. 20. The blood pump of claim 19 which carries a hard, lubricious protective coating over said conformal polymer coating to protect from wear and abrasion. 21. The blood pump of claim 14 which carries a hard, lubricious protective coating over said rotor to protect said rotor from wear and abrasion.