POSITIVE DISPLACEMENT PUMP SYSTEM AND METHOD

• US 20080008609A1
• Filed: 07/05/2007
• Published: 01/10/2008
• Est. Priority Date: 07/06/2006
• Status: Abandoned Application

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Gohean, Jeffrey, Longoria, Raul, Pate, Thomas, Smalling, Richard
• Application Number:
  US11/773,740
• Publication Number:
  US 20080008609A1
• Time in Patent Office: Days
• US Class Current: 417/415
• CPC Class Codes: A61M 2205/33 Controlling, regulating or measuring
• CPC Class Codes: A61M 2205/3303 Using a biosensor
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• 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 60/183 drawing blood from both ventricles, e.g. bi-ventricular assist devices [BiVAD]
• CPC Class Codes: A61M 60/258 Piston 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 60/441 generated by an electromotor
• CPC Class Codes: A61M 60/449 generated by a solenoid
• CPC Class Codes: A61M 60/459 generated by permanent magnets
• CPC Class Codes: A61M 60/462 Electromagnetic force
• CPC Class Codes: A61M 60/515 Regulation using real-time patient data
• 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 60/824 Hydrodynamic or fluid film bearings
• CPC Class Codes: A61M 60/835 of positive displacement blood pumps
• CPC Class Codes: A61M 60/892 Active valves, i.e. actuated by an external force
• CPC Class Codes: A61M 60/894 Passive valves, i.e. valves actuated by the blood
• CPC Class Codes: A61N 1/36514 controlled by a physiological quantity other than heart potential, e.g. blood pressure controlled by two or more physical parameters A61N1/36585
• CPC Class Codes: F04B 17/00 Pumps characterised by combination with, or adaptation to, specific driving engines or motors
• CPC Class Codes: F04C 13/001 : Pumps for particular liquids
• CPC Class Codes: F04C 2210/10 : working
• CPC Class Codes: F04C 2210/1016 : Blood

Abstract

Systems and methods including a motor or electromagnets to control the movement of one or more pistons in a pumping chamber. The pumping chamber may include a pump inlet and a pump outlet in fluid communication with the pumping chamber. Surfaces on a piston or pumping chamber may include hydrodynamic bearing surfaces.

Claims

1. A system comprising:

a pumping chamber forming a loop;

a pump inlet in fluid communication with the pumping chamber;

a pump outlet in fluid communication with the pumping chamber;

a first piston disposed within the pumping chamber;

a second piston disposed within the pumping chamber;

an electric motor; and

an electromagnet, wherein the system is configured such that during operation;

the electromagnet is initially coupled to the first piston;

the electric motor is initially coupled to the second piston;

the electromagnet is subsequently coupled to the second piston; and

the electric motor is subsequently coupled to the first piston.

2. The system of claim 1 wherein the system is configured such that during operation:

the electromagnet is coupled to either the first or second piston when the electromagnet is energized; and

the electromagnet is not coupled to either the first or second piston when the electromagnet is de-energized.

3. The system of claim 1, further comprising a magnetic ring, wherein the system is configured such that during operation:

the electric motor exerts a first magnetic force on the first piston;

the magnetic ring exerts a second magnetic force on the first piston; and

the first magnetic force opposes the second magnetic force.

4. The system of claim 3 wherein the magnetic ring comprises a permanent magnet or Halbach array.

5. The system of claim 1, wherein the system is configured such that during operation:

the motor comprises a rotor with a magnetic link;

the magnetic link is initially coupled to the second piston and subsequently coupled to the first piston.

6. The system of claim 5, wherein the magnetic link comprises a permanent magnet or Halbach array.

7. The system of claim 5, wherein the system is configured such that during operation:

a portion of the magnetic link extends beyond a leading face of the piston.

8. The system of claim 1, wherein the first piston and the second piston each comprise a permanent magnet or Halbach array.

9. The system of claim 1 wherein the system is configured such that during operation:

the pump inlet is inserted into a ventricle;

the pump outlet is in fluid communication with the ascending aorta, the descending aorta, or a pulmonary artery.

10. The system of claim 1 wherein the system is configured such that:

the motor comprises a rotor coupled to a linking arm;

the linking arm is coupled to a first magnet, wherein the first magnet is located on a first side of the piston during operation;

the linking arm is coupled to a second magnet, wherein the second magnet is located on a second side of the piston during operation; and

the first side is opposed to the second side.

11. The system of claim 1 wherein the first piston or the second piston comprise a hydrodynamic bearing surface.

14. The method of claim 11 wherein the first location is between the pump inlet and the pump outlet.

12. A method of pumping a fluid, the method comprising:

providing a pumping chamber, wherein the pumping chamber contains the fluid;

providing a pump inlet in fluid communication with the pumping chamber;

providing a pump outlet in fluid communication with the pumping chamber;

providing a first piston disposed within the pumping chamber;

providing a second piston disposed within the pumping chamber;

providing an electric motor comprising a rotor;

providing an electromagnet;

coupling the electromagnet to the first piston;

coupling the rotor to the second piston;

holding the first piston in a first location with the electromagnet;

rotating the rotor and moving the second piston closer to the first piston so that a portion of the fluid is forced out of the pump outlet;

de-energizing the electromagnet and uncoupling the electromagnet from the first piston;

energizing the electromagnet so that it couples to the second piston; and

coupling the rotor to the first piston.

13. The method of claim 12, further comprising:

rotating the rotor and moving the first piston closer to the second piston so that a portion of the fluid is forced out of the pump outlet.

15. A system comprising:

a pumping chamber comprising an inner surface forming a loop;

a pump inlet in fluid communication with the pumping chamber;

a pump outlet in fluid communication with the pumping chamber;

a piston disposed within the pumping chamber; and

a first electric motor magnetically coupled to the piston, wherein;

the piston comprises a hydrodynamic bearing surface configured to repel the piston away from the inner surface as the piston moves within the pumping chamber.

16. The system of claim 15, wherein:

the loop is centered about a central axis;

the piston comprises an upper surface, a lower surface, an inner surface, an outer surface, a leading face, and a trailing face; and

the inner surface comprises an upper wall, a lower wall, an inner wall and an outer wall.

17. The system of claim 16, wherein during operation:

a first lower gap exists between the lower surface and the lower wall proximal to the leading face;

a second lower gap exists between the lower surface and the lower wall proximal to the trailing face;

the first lower gap is larger than the second lower gap;

a first upper gap exists between the upper surface and the upper wall proximal to the leading face;

a second upper gap exists between the upper surface and the upper wall proximal to the trailing face; and

the first upper gap is larger than the second upper gap.

18. The system of claim 16, wherein a portion of the lower surface is not perpendicular to the central axis and a portion of the upper surface is not perpendicular to the central axis.

19. The system of claim 16, wherein:

a first outer gap exists between the outer surface and the outer wall proximal to the leading face;

a second outer gap exists between the outer surface and the outer wall proximal to the trailing face; and

the first outer gap is larger than the second outer gap.

20. The system of claim 15 further comprising a pinch valve between the pump inlet and the pump outlet.

21. The system of claim 15 further comprising:

a second piston disposed within the pumping chamber;

a second electric motor coupled to the second piston, wherein;

the second piston comprises a hydrodynamic bearing surface configured to repel the second piston away from the inner surface as the second piston moves within the pumping chamber.

22. The system of claim 15, further comprising:

a power supply;

a driver circuit electrically coupled to the electric motor and the power supply;

a microprocessor electrically coupled to the driver circuit; and

a sensor for sensing a position of the piston within the pumping chamber, wherein;

the driver circuit is configured to selectively couple the power supply to the electric motor upon receiving a control signal;

the sensor is electrically connected to the microprocessor;

the microprocessor is configured to interpret the position from the sensor; and

the microprocessor is configured to output the control signal to the driver circuit.

23. The system of claim 15 wherein a position and a velocity of the piston are controlled to produce a predetermined waveform in an outlet flow from the pump outlet.

24. The system of claim 15 further comprising a fluid within the pumping chamber and a sensor configured to measure a property of the fluid.

25. The system of claim 15, wherein the piston or inner surface comprise one or more of the following:

a nanoparticulate surface, a microporous coating, or a fibrous flocking configured to facilitate endothelial or pseudoneointimal protein or cell aggregation.

26. The system of claim 15, further comprising:

a pacemaker; and

a microprocessor, wherein

the pacemaker comprises one or more electrodes electrically coupled to a heart;

the pacemaker is electrically coupled to the microprocessor;

the pacemaker provides a depolarization output to the one or more electrodes;

the heart is controlled to contract at a predetermined time relative to an actuation stroke of the pump.

27. The system of claim 15 further comprising a sensor, wherein:

the sensor is configured to sense a physiological parameter;

the system is configured to increase or decrease a volumetric flow rate from the pumping chamber based on the physiological parameter.

28. The system of claim 27 wherein the sensor comprises one or more electrodes for measuring thoracic impedance, p-wave activity, renal sympathetic nerve activity, or aortic nerve activity.

29. The system of claim 27 wherein the sensor comprises an accelerometer for sensing a heart contraction, a diaphragm motion, a bodily inclination, or a walking pace.

30. A pump for circulating fluid comprising:

a pumping chamber;

a pump inlet in fluid communication with the pumping chamber;

a pump outlet in fluid communication with the pumping chamber;

a drive piston disposed within the pumping chamber; and

a hollow valve sleeve configured to recess into the pump outlet.

31. A system comprising:

a pumping chamber forming a loop;

a pump inlet in fluid communication with the pumping chamber;

a pump outlet in fluid communication with the pumping chamber;

a piston disposed within the pumping chamber;

an electric motor comprising a rotor coupled to a shaft;

a magnet coupled to an end of the shaft;

a sensor proximal to the magnet; and

a control system, wherein;

the electric motor is magnetically coupled to the piston;

the magnet produces a magnetic vector that rotates with the rotor;

the sensor is configured sense the magnetic vector; and

the control system is configured to determine the angular position of the rotor.

32. The system of claim 31, wherein the sensor is a 2-axis Hall effect sensor.

33. The system of claim 31, wherein the electric motor is an axial flux motor.

34. The system of claim 31, wherein the control system is configured to access a lookup table.

35. A system comprising:

a pumping chamber comprising an inner surface forming a loop;

a pump inlet in fluid communication with the pumping chamber;

a pump outlet in fluid communication with the pumping chamber;

a first piston disposed within the pumping chamber; and

a series of electromagnets disposed around the pumping chamber, wherein;

the series of electromagnets are configured to move the first piston around the pumping chamber; and

the first piston comprises a hydrodynamic bearing surface configured to repel the first piston away from the inner surface as the first piston moves within the pumping chamber.

36. The system of claim 35 further comprising a second piston disposed within the pumping chamber, wherein:

the series of electromagnets are configured to move the second piston around the pumping chamber; and

the second piston comprises a hydrodynamic bearing surface configured to repel the second piston away from the inner surface as the second piston moves within the pumping chamber.

37. The system of claim 35 further comprising a pinch valve between the pump inlet and pump outlet.