Patent ID: 9561313
Date: 2017-02-07
CPC Classifications: A61M,F04D

Claim:
1. A rotor for an axial flow blood pump, the rotor having an axis extending in upstream and downstream axial directions and a plurality of generally helical blades extending from an inflow end of the rotor to an outflow end of the rotor, the blades projecting outwardly away from the axis in outward spanwise directions, the blades being coextensive in the axial directions and spaced apart from one another in a circumferential direction around the axis so as to define generally helical channels between adjacent ones of the blades, each said blade having a pressure surface facing in a forward circumferential direction, a suction surface facing in a rearward circumferential direction and a tip surface extending between the pressure and suction surfaces of the blade, each said channel being bounded by the pressure surface of one of said blades and the suction surface of a next adjacent one of said blades, the tip surfaces of the blades defining hydrodynamic bearing surfaces capable of suspending the rotor, wherein the pressure surface of each said blade includes an outflow corner surface at the outflow end of that blade, the outflow corner surface of each said blade extending over a major portion of the extent of that blade in the outward spanwise direction of that blade, the outflow corner surface sloping rearwardly in the downstream axial direction and extending to within 0.4 mm of the suction surface of the blade at a downstream extremity of the blade adjacent the tip surface of the blade, and wherein, over at least a major portion of the outflow corner surface, a vector normal to the outflow corner surface has positive, non-zero components in the outward spanwise direction of that blade direction and in the downstream axial direction.