Axial pump

• US 5,692,882 A
• Filed: 05/22/1996
• Issued: 12/02/1997
• Est. Priority Date: 11/10/1993
• Status: Expired due to Term

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Svejkovsky, Paul A., Benkowski, Robert J., Aber, Gregory S., Bacak, James W., Bozeman, Richard J. Jr., Akkerman, James W., Damm, George Arthur Van
• Primary Examiner(s): Thorpe, Timothy
• Assistant Examiner(s): THAI, XUAN MARIAN
• Application Number:
  US08/653,929
• Time in Patent Office: 559 Days
• Field of Search: 417/45, 417/244, 417/266, 417/348, 417/356, 417/366, 417/420, 417/423.1, 417/423.5, 417/423.7, 417/405-8, 415/71-73, 415/900, 416/3, 416/176-177, 310/90.5, 310/156, 310/216-218
• US Class Current: 417/45
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 60/113 in other functional devices, e.g. dialysers or heart-lung machines
• CPC Class Codes: A61M 60/148 in line with a blood vessel using resection or like techniques, e.g. permanent endovascular heart assist devices
• CPC Class Codes: A61M 60/178 drawing blood from a ventricle and returning the blood to the arterial system via a cannula external to the ventricle, e.g. left or right ventricular assist devices
• CPC Class Codes: A61M 60/237 the blood flow through the rotating member having mainly axial components, e.g. axial flow pumps
• CPC Class Codes: A61M 60/422 the force acting on the blood contacting member being electromagnetic, e.g. using canned motor pumps
• CPC Class Codes: A61M 60/538 Regulation using real-time blood pump operational parameter data, e.g. motor current
• CPC Class Codes: A61M 60/546 of blood flow, e.g. by adapting rotor speed
• CPC Class Codes: A61M 60/562 for making blood flow pulsatile in blood pumps that do not intrinsically create pulsatile flow
• CPC Class Codes: A61M 60/812 Vanes or blades, e.g. static flow guides
• CPC Class Codes: A61M 60/816 Sensors arranged on or in the housing, e.g. ultrasound flow sensors
• CPC Class Codes: A61M 60/822 specially adapted for being actively controlled
• CPC Class Codes: A61M 60/824 Hydrodynamic or fluid film bearings
• CPC Class Codes: A61M 60/825 Contact bearings, e.g. ball-and-cup or pivot bearings
• CPC Class Codes: A61M 60/827 Sealings between moving parts
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: F04B 17/03 driven by electric motors
• CPC Class Codes: F04B 49/06 Control using electricity regulating by means of floats actuating electric switches F04B49/04
• CPC Class Codes: F16C 17/08 for supporting the end face of a shaft or other member, e.g. footstep bearings
• CPC Class Codes: F16C 2316/18 Pumps for pumping blood
• CPC Class Codes: Y10S 415/90 : Rotary blood pump
• CPC Class Codes: Y10T 29/49236 : Fluid pump or compressor making
• CPC Class Codes: Y10T 29/49238 : Repairing, converting, servicing or salvaging
• CPC Class Codes: Y10T 29/49245 : Vane type or other rotary, e.g., fan

Abstract

A rotary blood pump includes a pump housing for receiving a flow straightener, a rotor mounted on rotor bearings and having an inducer portion and an impeller portion, and a diffuser. The entrance angle, outlet angle, axial and radial clearances of blades associated with the flow straightener, inducer portion, impeller portion and diffuser are optimized to minimize hemolysis while maintaining pump efficiency. The rotor bearing includes a bearing chamber that is filled with cross-linked blood or other bio-compatible material. A back emf integrated circuit regulates rotor operation and a microcomputer may be used to control one or more back emf integrated circuits. A plurality of magnets are disposed in each of a plurality of impeller blades with a small air gap. A stator may be axially adjusted on the pump housing to absorb bearing load and maximize pump efficiency.

Claims

1. A fluid pump, comprising:

a pump housing having a fluid flow path therethrough;

a first stator mounted to said pump housing, said first stator having a first stator field winding for producing a first stator magnetic field;

a first rotor mounted within said pump housing for rotation about a longitudinal axis of said first rotor in response to said first stator magnetic field, said first rotor carrying a blade thereon for propelling fluid through said pump housing along said fluid flow path, at least a portion of said blade being affixed to said rotor at an angle that is offset with respect to said longitudinal axis;

a plurality of magnets secured to said at least a portion of said blade affixed to said rotor at an angle that is offset with respect to said longitudinal axis, said plurality of magnets producing a first rotor magnetic field that passes through said first stator field winding during said rotation of said first rotor to induce a back emf within said first stator field winding; and

back emf sensor circuitry connected to said first stator field winding to sense said back emf produced during said rotation of said first rotor within said pump housing.

2. A fluid pump, comprising:

a pump housing defining therein a fluid path for fluid flow through said pump;

a rotor mounted within said pump housing for rotation therein about a rotor axis;

impeller means for moving a fluid through said fluid path, said impeller means comprising at least one impeller blade on said rotor;

a plurality of magnets secured to said rotor;

a stator in surrounding relationship to said pump housing, said stator and said plurality of magnets being positioned to define a magnetic flux gap therebetween having a radial spacing of less than 0.025 inches.

3. The pump of claim 2, further comprising:

at least one rotor mount for rotably securing said rotor; and

at least one clamp for securing said at least one rotor mount within said pump housing, said pump housing being sufficiently thin-walled such that tightening of said at least one clamp acts to deform said pump housing so as to affix said at least one rotor mount thereto.

4. The pump of claim 2, wherein:

said plurality of magnets are arranged in helical fashion about said rotor, said plurality of magnets being movable with respect to said stator.

5. The pump of claim 2, wherein:

said stator is adjustable with respect to said pump housing and said rotor along an axis substantially collinear with said rotor axis.

6. The pump of claim 2, further comprising:

a radially peripheral edge of said at least one impeller blade, said plurality of magnets being mounted along said radially peripheral edge, at least two of said plurality of magnets being in close proximity.

7. A rotary motor, comprising:

a motor housing;

a rotor mounted within said motor housing for rotation about a rotor axis, said rotor having a circumference;

a stator mounted to said motor housing to produce a magnetic field for rotatably driving said rotor; and

a plurality of individual permanent magnets positioned along said circumference of said rotor with a variable axial position with respect to said rotor axis such that said plurality of individual permanent magnets define at least a portion of a helical pattern and are moveable with respect to said stator.

8. The rotary motor of claim 7, further comprising:

at least one clamp disposed around said motor housing, said motor housing being sufficiently thin-walled to facilitate deformation of said motor housing for mounting of said rotor by tightening of said at least one clamp.

9. The rotary motor of claim 7, wherein:

said plurality of individual permanent magnets are mounted with a radial magnetic flux gap spacing to said stator of less than 0.025 inches.

10. The rotary motor of claim 7, further comprising:

at least one impeller blade mounted to said rotor, said plurality of individual magnets being affixed along a peripheral edge of said at least one impeller blade such that at least two of said individual permanent magnets are closely proximate to each other along said peripheral edge.

11. The rotary motor of claim 7, wherein said stator further comprises:

a plurality of laminations, said laminations being stacked together such that a passageway is formed therein, said passageway being skewed with respect to said rotor axis.

12. The rotary motor of claim 7, wherein:

said at least one impeller blade has a variable pitch.

13. A rotary motor, comprising:

a motor housing;

a rotor mounted within said motor housing for rotation about a rotor axis, said rotor having a circumference;

a plurality of individual permanent magnets positioned along said circumference of said rotor; and

a stator mounted to said motor housing to produce a magnetic field for rotatably driving said rotor, said stator comprising a plurality of laminations, said laminations being stacked together such that a passageway formed therein is skewed with respect to said rotor axis, a stator winding within said passageway that follows said passageway so as to be skewed with respect to said rotor axis.

14. The rotary motor of claim 13, wherein:

said stator is axially adjustable with respect to said motor housing.

15. The rotary motor of claim 13, further comprising:

a clamp external to said motor housing for securing said rotor axially with respect to said motor housing.

16. The rotary motor of claim 15, wherein:

said motor housing is sufficiently thin-walled to be deformable by said clamp.

17. The rotary motor of claim 13, wherein:

said plurality of individual permanent magnets include more than two individual magnets.

18. A fluid pump, comprising:

a pump housing defining therein a fluid path for fluid flow through said pump;

a rotor mounted within said pump housing for rotation therewith;

a rotor mount within said pump housing for rotatable mounting of said rotor within said pump housing; and

a clamp surrounding an external portion of said pump housing, said pump housing being deformable in the locus of said clamp for securing said rotor mount within said housing by tightening of said clamp.

19. The fluid pump of claim 18, wherein:

said rotor mount is comprised of reinforced plastic to prevent plastic creep deformation.

20. The fluid pump of claim 18, further comprising:

a plurality of magnets secured to said rotor.

21. The fluid pump of claim 20, further comprising:

a stator surrounding said pump housing, said plurality of magnets being positioned radially outwardly on said rotor to minimize a gap formed between said plurality of magnets and said stator.