Rotary blood pump with opposing spindle magnets, bore and drive windings
Various “contactless” bearing mechanisms including hydrodynamic and magnetic bearings are provided for a rotary pump as alternatives to mechanical contact bearings. In one embodiment, a pump apparatus includes a pump housing defining a pumping chamber. The housing has a spindle extending into the pumping chamber. A spindle magnet assembly includes first and second magnets disposed within the spindle. The first and second magnets are arranged proximate each other with their respective magnetic vectors opposing each other. The lack of mechanical contact bearings enables longer life pump operation and less damage to working fluids such as blood.
1. A centrifugal blood pump comprising:
a pump housing defining a pumping chamber;
a center post extending into said pumping chamber;
a rotor configured to rotate around said center post;
said rotor being biased axially in a first direction when said rotor is in a non-rotating state;
a plurality of contoured surfaces disposed between said housing and said rotor so as to create a hydrodynamic bearing which generates forces in a direction parallel to said first direction when said rotor is in a rotating state;
a passive axial magnetic bearing supportive of said rotor;
a plurality of drive magnets disposed in said rotor;
said passive axial magnetic bearing being adjustable so as to modify the bias of said rotor in said first direction; and
wherein said passive axial magnetic bearing comprises a center post component and a rotor component, one of which is axially adjustable relative to the other.
2. A pump according to claim 1 , wherein said contoured surfaces are curved and tapered ramps.
3. A pump according to claim 2 , wherein said contoured surfaces are disposed on said rotor.
4. A pump according to claim 1 wherein said hydrodynamic bearing generates forces in a direction parallel and opposite to said first direction when said rotor is in a rotating state.
5. A pump according to claim 1 , wherein said rotor component of said passive axial magnetic bearing comprises first and second rotor magnets proximately disposed to each other.
6. A pump according to claim 5 , further comprising an element disposed between said first and second rotor magnets.
7. A pump according to claim 6 , wherein the element is a pole piece for concentrating a magnetic flux produced by said rotor magnets.
8. A pump according to claim 7 , wherein said element is a flux concentrator.
9. A pump according to claim 6 , wherein said element is a spacer.
10. A pump according to claim 1 , further comprising a set screw for longitudinal adjustment of said passive axial magnetic bearing.
11. A centrifugal blood pump comprising:
a pump housing;
a spindle extending into said housing;
a rotor situated over said spindle and biased in a first direction;
a plurality of surfaces disposed between said housing and said rotor so as to create a hydrodynamic bearing which generates forces in a direction parallel to said first direction when said rotor is in a rotating state;
a passive axial magnetic bearing providing at least axial support to said rotor;
said passive axial magnetic bearing having at least one adjustable magnetic component so as to modify the bias of said rotor in said first direction; and
wherein said passive axial magnetic bearing comprises a spindle component and a rotor component, one of which comprises said at least one adjustable component.
12. A pump according to claim 11 , wherein said surfaces are curved and tapered ramps.
13. A pump according to claim 12 , wherein said surfaces are disposed on said rotor.
14. A pump according to claim 11 , wherein said hydrodynamic bearing generates forces in a direction parallel and opposite to said first direction when said rotor is in a rotating state.
15. A pump according to claim 11 , wherein said rotor component of said passive axial magnetic bearing comprises first and second rotor magnets proximately disposed to each other.
16. A pump according to claim 15 , further comprising an element disposed between said first and second rotor magnets.
17. A pump according to claim 16 , wherein the element is a pole piece for concentrating a magnetic flux produced by said rotor magnets.
18. A pump according to claim 17 , wherein said element is a flux concentrator.
19. A pump according to claim 16 , wherein said element is a spacer.