Blood pump having a magnetically suspended rotor

A system for pumping blood, comprising:

• (i) a pump, comprising:
• a housing that has an inlet and an outlet;
• a stator disposed within the housing and having a first end, disposed at the inlet, about which a plurality of stator blades are disposed, a second end, disposed at the outlet, about which a plurality of stator blades are disposed and a stationary hub that connects the first end to the second end;
• a rotor, suspended between the stationary hub and the housing;
• a first radial magnet bearing defined by a first set of magnets of alternating polarity, disposed within the rotor, that define an outer race and a second set of magnets of alternating polarity, disposed within the stator stationary hub, that define an inner race, the inner race and the outer race communicating across a gap between the stationary hub and the rotor to suspend the rotor about the stationary hub;
• a thrust bearing defined by a pair of thrust coils, disposed within the housing, and a pair of magnetic poles, disposed within the rotor, each of the thrust coils interacting with one of the magnetic poles to produce an axial force on the rotor to position the rotor axially within the housing;
• a sensing coil, disposed within the stator, that senses the axial position of the rotor;
• and
• (ii) a controller, coupled to the sensing coil of the pump that controls an electrical current flowing through the thrust coils to produce a correcting force that positions the rotor axially in response to the position sensed by the sensing coil.

A pump for pumping blood, comprising:

• a housing that has an inlet and an outlet;
• a stator, disposed within the housing, and having a first end, that is coupled to the housing proximate to the inlet and a second end, that is coupled to the housing proximate to the outlet;
• a rotor, magnetically suspended between the stator and the housing;
• a radial magnetic bearing that includes a rotor magnet, disposed within the rotor, and a stator magnet, disposed within the stator and aligned with the rotor magnet, the interaction of the rotor magnet and the stator magnet suspending the rotor radially between the housing and the stator;
• a primary flow path defined between the rotor and the housing;
• a secondary flow path defined between the rotor and the stator, the secondary flow path being large enough to provide adequate flushing of the secondary flow path and small enough so that the rotor magnet and the stator magnet can interface to suspend the rotor radially.