Sealless rotodynamic pump with fluid bearing

• US 5,370,509 A
• Filed: 12/08/1993
• Issued: 12/06/1994
• Est. Priority Date: 05/08/1989
• Status: Expired due to Term

• Current Assignee: Cleveland Clinic Foundation
• Original Assignee: Cleveland Clinic Foundation
• Inventors: Wade, Warren F., Smith, William A., Golding, Leonard A. R.
• Primary Examiner(s): Bertisch, Richard A.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US08/164,027
• Time in Patent Office: 363 Days
• Field of Search: 417/423.1, 417/423.7, 417/354, 604/151, 415/900
• US Class Current: 417/423.1
• 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 60/196 replacing the entire heart, e.g. total artificial hearts [TAH]
• CPC Class Codes: A61M 60/221 the blood flow through the rotating member having both radial and axial components, e.g. mixed flow pumps
• CPC Class Codes: A61M 60/226 the blood flow through the rotating member having mainly radial components
• CPC Class Codes: A61M 60/232 Centrifugal pumps
• 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 60/419 the force acting on the blood contacting member being permanent magnetic, e.g. from a rotating magnetic coupling between driving and driven magnets
• 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 60/81 Pump housings
• CPC Class Codes: A61M 60/824 Hydrodynamic or fluid film bearings
• CPC Class Codes: F04D 1/04 Helico-centrifugal pumps
• CPC Class Codes: F04D 13/0673 the motor being of the inside-out type
• CPC Class Codes: F04D 29/0413 hydrostatic; hydrodynamic thrust bearings
• CPC Class Codes: F04D 29/0467 Spherical bearings
• CPC Class Codes: F04D 29/047 hydrostatic; hydrodynamic
• CPC Class Codes: F04D 3/02 of screw type
• CPC Class Codes: Y10S 415/90 Rotary blood pump

Abstract

A sealless centrifugal blood pump is provided in which a rotatable impeller is supported in a pump housing by fluid bearings during operation. Rotational movement of the impeller is accomplished with an inverted motor for magnetically driving of the impeller and maintenance of the axial running position of the impeller relative to the housing. In an alternative embodiment, the axis of the rotor housing is radially displaced relative to the axes of drive element of the motor and the motor housing.

Claims

1. A rotodynamic pump comprising:

a housing having an inlet and outlet in fluid communication with a chamber;

a rotor having an impeller received in the chamber;

a drive assembly for rotating the rotor relative to the housing including a drive element and a driven element operatively associated with the rotor;

a fluid bearing for solely supporting the rotor in the chamber provided by an extension of an end wall of the chamber; and

a first blade set for continually renewing the fluid in contact with all wetted surfaces of the chamber.

2. The pump as defined in claim 1 further comprising first and second generally radially spaced circumferentially continuous fluid flow passages defined between the housing and the rotor.

3. The pump as defined in claim 2 wherein the first blade set urges fluid flow through the second passage.

4. The pump as defined in claim 2 further comprising a second blade set operatively associated with the rotor, the second blade set pumping fluid from the inlet to the outlet, and the first blade set urging fluid through the second passage.

5. The pump as defined in claim 2 further comprising an opening in the rotor connecting the first and second passages for permitting fluid flow therebetween.

6. The pump as defined in claim 2 wherein the second passage has a narrowed portion to define the fluid bearing.

7. The pump as defined in claim 6 further comprising a groove on a sidewall of the second passage for passing flow through the fluid bearing.

8. The pump as defined in claim 6 wherein the second passage has a second narrowed portion to define a second fluid bearing.

9. The pump as defined in claim 8 further comprising a groove on a sidewall of the second passage for passing flow through the second fluid bearing.

10. The pump as defined in claim 1 the first set of blades on the rotor urges fluid flow through the fluid bearing.

11. The pump as defined in claim 10 further comprising a thrust reaction member operatively associated with the drive and driven elements for resisting longitudinal displacements caused by axial fluid, gravitational, inertial or other forces.

12. The pump as defined in claim 1 further comprising means for limiting axial travel of the rotor relative to the housing.

13. The pump as defined in claim 1 wherein the drive comprises an electric motor having a rotor portion and a stator portion.

14. The pump as defined in claim 1 wherein the drive assembly comprises an electric motor with a stator portion smaller in diameter than a rotor portion.

15. The pump as defined in claim 1 wherein the drive assembly comprises a magnetic coupling in combination with a prime mover.

16. The pump as defined in claim 1 further comprising blood as the fluid.

17. A rotodynamic pump comprising:

a housing having an inlet and an outlet in fluid communication with a chamber;

a shaftless rotor received in the chamber for selective rotation relative to the housing;

a drive assembly for rotating the rotor relative to the housing including a drive element and a driven element operatively associated with the rotor;

a fluid bearing defined between the rotor and the housing; and

first set of blades for continually renewing the fluid in contact with all wetted surfaces on the chamber.

18. The pump as defined in claim 17 further comprising first and second radially spaced continuous flow passages defined between the rotor and the housing.

19. The pump as defined in claim 18 further comprising an opening through the rotor connecting the first and second passages for permitting flow therebetween.

20. The blood pump as defined in claim 18 wherein the rotor includes a second set of blades disposed in the first passage to pump fluid from the inlet to the outlet.

21. The pump as defined in claim 20 wherein the first blade set scavenges fluid from the second passage to enhance fluid through flow.

22. The blood pump as defined in claim 18 wherein the second passage is narrowed at one end to define the fluid bearing.

23. The pump as defined in claim 22 further comprising a groove in a side wall of the second passage to increase the area for flow through the fluid bearing.

24. The pump as defined in claim 22 wherein the second passage is narrowed at the other end to define a second fluid bearing.

25. The pump as defined in claim 24 further comprising a groove in a side wall of the second passage to increase the area for flow through the fluid bearing.

26. The pump as defined in claim 17 wherein the drive assembly includes an electric motor stator and winding in the housing portion and a surrounding permanent magnet assembly in the rotor.

27. The pump as defined in claim 17 wherein the magnetic attraction of the drive and driven elements of the drive assembly define a thrust reaction arrangement to resist longitudinal displacements caused by axial fluid, gravitational inertial or other forces.

28. The pump as defined in claim 17 further comprising means for limiting axial travel of the rotor relative to the housing.

29. The pump as defined in claim 28 wherein the limiting means includes a contact surface adapted to selectively contact the rotor.

30. The pump as defined in claim 17 wherein the drive assembly comprises a magnetic coupling in combination with a prime mover.

31. The pump as defined in claim 17 further comprising blood as the working fluid.

32. A rotodynamic blood pump comprising:

a housing having an inlet and an outlet in fluid communication with a chamber, the housing including a housing portion that extends axially inward to the chamber from an end wall;

an annular rotor received in the chamber around the housing portion for selective rotation relative to the housing, the rotor being spaced from the housing and housing portion to define radially spaced first and second passages, the first passage extending between the inlet and outlet and containing an impeller blade set on the rotor for urging flow from the inlet to the outlet, and the second passage being narrowed at first and second ends to form fluid bearings;

a drive assembly for rotating the rotor relative to the housing including a ferromagnetic assembly received in the rotor and an electric motor stator and winding assembly installed in the housing and radially coupled to the ferromagnetic assembly in the rotor; and

means for continually renewing the blood in contact with all wetted surfaces of the chamber.

33. The blood pump as defined in claim 32 wherein the magnetic attraction of the motor stator and ferromagnetic assembly defines a thrust reaction arrangement to resist longitudinal displacements caused by axial fluid, gravitational, inertial or other forces.

34. The blood pump as defined in claim 32 wherein one end of the annular rotor is conically narrowed and cooperates with strut means on the rotor housing for limiting axial travel of the rotor relative to the housing.

35. The blood pump as defined in claim 32 further comprising means for urging blood flow through the second passage independent of the flow in the first passage.

36. The blood pump as defined in claim 32 further comprising a second blade set on the rotor for urging flow through the second passage.

37. The blood pump as defined in claim 32 further comprising an opening in the annular rotor connecting the first and second passages for permitting blood flow therebetween.

38. The blood pump as defined in claim 32 further comprising plural spaced grooves on the housing portion adjacent first and second ends of the second passage for increasing flow area through the fluid bearings.

39. The pump as defined in claim 32 wherein the axis of the motor stator is radially displaced relative to the axis of the housing to produce a radial force of known magnitude and direction.

40. The pump as defined in claim 32 wherein the axis of the housing is radially displaced relative to the axes of the motor stator and the housing portion to provide closer alignment of the housing axis with the rotor axis of rotation during pumping.

41. A rotodynamic pump comprising:

a housing having an inlet and an outlet in fluid communication with a chamber;

a rotor having an impeller received in the chamber;

a drive assembly for rotating the rotor relative to the housing including a drive element and a driven element operatively associated with the rotor;

fluid bearing means for primarily supporting the rotor in the chamber provided by an extension of an end wall of the chamber; and

means for continually renewing the fluid in contact with all wetted surfaces of the chamber.