US20130330219A1 - Magnetically suspended pump - Google Patents

Magnetically suspended pump Download PDF

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Publication number
US20130330219A1
US20130330219A1 US13/897,107 US201313897107A US2013330219A1 US 20130330219 A1 US20130330219 A1 US 20130330219A1 US 201313897107 A US201313897107 A US 201313897107A US 2013330219 A1 US2013330219 A1 US 2013330219A1
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United States
Prior art keywords
rotor
permanent magnet
housing
axial
stator
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US13/897,107
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English (en)
Inventor
Jeffrey A. LaRose
Charles R. Shambaugh, JR.
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Heartware Inc
Original Assignee
Heartware Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Heartware Inc filed Critical Heartware Inc
Priority to US13/897,107 priority Critical patent/US20130330219A1/en
Assigned to HEARTWARE, INC. reassignment HEARTWARE, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: LAROSE, JEFFREY A., SHAMBAUGH, CHARLES R., JR.
Publication of US20130330219A1 publication Critical patent/US20130330219A1/en
Abandoned legal-status Critical Current

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04DNON-POSITIVE-DISPLACEMENT PUMPS
    • F04D13/00Pumping installations or systems
    • F04D13/02Units comprising pumps and their driving means
    • F04D13/06Units comprising pumps and their driving means the pump being electrically driven
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61MDEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M60/00Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
    • A61M60/10Location thereof with respect to the patient's body
    • A61M60/122Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body
    • A61M60/165Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body implantable in, on, or around the heart
    • A61M60/178Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body implantable in, on, or around the heart 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
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61MDEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M60/00Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
    • A61M60/20Type thereof
    • A61M60/205Non-positive displacement blood pumps
    • A61M60/216Non-positive displacement blood pumps including a rotating member acting on the blood, e.g. impeller
    • A61M60/237Non-positive displacement blood pumps including a rotating member acting on the blood, e.g. impeller the blood flow through the rotating member having mainly axial components, e.g. axial flow pumps
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61MDEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M60/00Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
    • A61M60/40Details relating to driving
    • A61M60/403Details relating to driving for non-positive displacement blood pumps
    • A61M60/422Details relating to driving for non-positive displacement blood pumps the force acting on the blood contacting member being electromagnetic, e.g. using canned motor pumps
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61MDEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M60/00Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
    • A61M60/80Constructional details other than related to driving
    • A61M60/802Constructional details other than related to driving of non-positive displacement blood pumps
    • A61M60/818Bearings
    • A61M60/82Magnetic bearings
    • A61M60/822Magnetic bearings specially adapted for being actively controlled
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61MDEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M60/00Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
    • A61M60/80Constructional details other than related to driving
    • A61M60/802Constructional details other than related to driving of non-positive displacement blood pumps
    • A61M60/818Bearings
    • A61M60/824Hydrodynamic or fluid film bearings
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04DNON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00Details, component parts, or accessories
    • F04D29/04Shafts or bearings, or assemblies thereof
    • F04D29/041Axial thrust balancing
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04DNON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00Details, component parts, or accessories
    • F04D29/04Shafts or bearings, or assemblies thereof
    • F04D29/046Bearings
    • F04D29/048Bearings magnetic; electromagnetic
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04DNON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00Details, component parts, or accessories
    • F04D29/05Shafts or bearings, or assemblies thereof, specially adapted for elastic fluid pumps
    • F04D29/051Axial thrust balancing
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04DNON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00Details, component parts, or accessories
    • F04D29/05Shafts or bearings, or assemblies thereof, specially adapted for elastic fluid pumps
    • F04D29/056Bearings
    • F04D29/058Bearings magnetic; electromagnetic
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61MDEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M60/00Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
    • A61M60/10Location thereof with respect to the patient's body
    • A61M60/122Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body
    • A61M60/126Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body implantable via, into, inside, in line, branching on, or around a blood vessel
    • A61M60/148Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body implantable via, into, inside, in line, branching on, or around a blood vessel in line with a blood vessel using resection or like techniques, e.g. permanent endovascular heart assist devices
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16CSHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2316/00Apparatus in health or amusement
    • F16C2316/10Apparatus in health or amusement in medical appliances, e.g. in diagnosis, dentistry, instruments, prostheses, medical imaging appliances
    • F16C2316/18Pumps for pumping blood
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16CSHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00Bearings not otherwise provided for
    • F16C32/04Bearings not otherwise provided for using magnetic or electric supporting means
    • F16C32/0406Magnetic bearings
    • F16C32/0408Passive magnetic bearings
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16CSHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00Bearings not otherwise provided for
    • F16C32/04Bearings not otherwise provided for using magnetic or electric supporting means
    • F16C32/0406Magnetic bearings
    • F16C32/0408Passive magnetic bearings
    • F16C32/0423Passive magnetic bearings with permanent magnets on both parts repelling each other
    • F16C32/0429Passive magnetic bearings with permanent magnets on both parts repelling each other for both radial and axial load, e.g. conical magnets

Definitions

  • Ventricular assist devices may utilize a blood pump for imparting momentum to a patients blood thereby driving the blood to a higher pressure.
  • a ventricular assist device is a Left Ventricular Assist Device (LVAD).
  • the blood inlet of the LVAD is connected to the left ventricle of the patient's heart, whereas the blood outlet of the LVAD is connected to the patient's aorta. Oxygenated blood from the ventricle enters the LVAD and is pumped by the LVAD into the patient's aorta.
  • LVAD Left Ventricular Assist Device
  • Certain LVADs use rotary pumps.
  • a rotary pump includes a rotor that spins about an axis within the housing of pump and imparts momentum to the blood.
  • Rotary blood pumps may be either centrifugal or axial, In a radial flow or centrifugal blood pump, blood enters the pump along its axis of rotation and exits the pump remote from the axis of rotation. In an axial flow blood pump, blood enters the pump along its axis of rotation and exits the pump along the axis of rotation.
  • Certain rotary blood pumps use mechanical bearings to support and position in the axial and radial directions. Mechanical bearings in contact with the blood can cause of thrombosis. Moreover, mechanical bearings that have contact between a part fixed to the housing and a part fixed to the rotor are subject to wear. This can pose a considerable problem, particularly in a blood pump that must remain implanted within the patient for many years.
  • non-contact bearings have been employed. These bearings utilize magnetic or hydrodynamic forces to suspend the rotor within the housing.
  • a magnetic bearing including a multipole, rod-like permanent magnet, such as an assemblage of magnetic discs, on the rotor.
  • the rotor permanent magnet is disposed within a multi-pole generally tubular permanent magnet, such as an assemblage of magnetic rings, on the housing. Repulsion forces between like poles of these magnets help to maintain the rotor coaxial with the housing.
  • these permanent magnets act as a radial bearing with constrains the rotor in radial directions. These permanent magnets also produce an axial thrust on the rotor. The axial position of the rotor relative to the housing is maintained by magnetic or hydrodynamic thrust bearings separate from the radial bearing. Because bearings that rely only on permanent magnets do not require an external source of power and do not require any control circuitry, they are commonly referred to as “passive” magnetic bearings.
  • U.S. Pat. No. 6,234,772 to Wampler et al. discloses certain embodiments using a passive magnetic radial bearing incorporating a permanent magnet on a spindle fixed to the pump housing.
  • the spindle is received within a bore in the rotor.
  • the rotor has a tubular permanent magnet surrounding the spindle.
  • the '772 Patent uses hydrodynamic thrust bearings to control axial position of the rotor.
  • a blood pump which includes a housing having an axis and first and second stator permanent magnets fixed relative to the housing at axially-spaced locations.
  • the pump according to this aspect of the invention desirably also includes a rotor having an axis disposed within the pump housing including a first rotor permanent magnet associated with and magnetically interacting with the first stator permanent magnet and a second rotor permanent magnet associated with and magnetically interacting with the second stator permanent magnet, so that the interacting magnets urge the rotor into an alignment coaxial with the housing.
  • the magnets are constructed and arranged so that first stator permanent magnet exerts a first axial force on the first rotor permanent magnet in a first axial direction and the second stator permanent magnet exerts a second axial force on the second rotor permanent magnet in a second axial direction opposite to the first axial direction.
  • the rotor and stator permanent magnets desirably are arranged so that, over an operating range of axial positions of the rotor relative to housing, the first axial force decreases upon movement of the rotor relative to the housing in the first axial direction, whereas the second axial force decreases upon movement of the rotor relative to the housing in the second axial direction.
  • the first and second axial forces urge the rotor towards an equilibrium position within the operating range.
  • the rotor can be suspended and positioned within the housing entirely by interactions between the aforementioned rotor and stator permanent magnets.
  • Preferred embodiments of the present invention can provide simple and compact pumps.
  • FIG. 1 is a cross-sectional view of an axial flow blood pump according to the prior art.
  • FIG. 2A is a schematic view of an axial flow blood pump according to one embodiment of the invention.
  • FIG. 2B is a schematic view of the interaction of magnetic bearings in the axial flow blood pump of FIG. 2A .
  • FIG. 3 is a schematic view of an alternate embodiment of an axial flow blood pump according to a further embodiment of the invention.
  • FIG. 1 illustrates a cross sectional view of a portion of the axial blood pump disclosed in the '863 Publication. Although incorporated by reference, certain portions of the '863 Publication are reproduced below to more fully explain that disclosure.
  • blood flow is designed to flow in the direction from inflow lumen 37 to outflow lumen 38 and thereby respectively guide the blood flow into and out of pump.
  • the rotor assembly 60 spins and pumps blood via attached impeller blades 62 .
  • Stationary stator blades 102 direct the flow at the outlet end 22 of the blood pump 20 .
  • the rotor assembly 60 is rotated via a 4-pole motor assembly 124 forming stator components including motor iron 125 , motor windings 126 , and potting material 127 and rotor components including motor magnets 70 .
  • FIG. 1 also shows radial support to the rotor assembly provided by fore and aft PM magnetic bearings.
  • the fore PM magnetic bearing includes rotor PM rings 68 a and 68 b and corresponding stator PM rings 121 a and 121 b.
  • the aft PM magnetic bearing includes rotor PM rings 68 c and 68 d and corresponding stator PM rings 121 c and 121 d.
  • the magnetization directions of the various PM components are indicated with arrows.
  • the PM magnetic bearings provide a radial magnetic spring force that stabilizes and centers the rotor assembly 60 with a positive spring characteristic
  • the PM magnetic bearings also create a negative spring characteristic in the axial direction which makes the rotor axially unstable.
  • a feedback-controlled voice-coil actuator acts on the rotor assembly 60 in the axial direction.
  • the voice-coil actuator is comprised of voice coils 129 a and 129 b wired such that current flows in opposite directions in the two coils 129 a, 129 b and thus interacts with magnets 71 , 72 , and 73 to produce an axial force in response to an electronically-controlled current in the coils 129 a, 129 b .
  • Magnet 68 b also contributes to the function of the voice-coil actuator, as it is proximal to voice coil 129 a and contributes to the radial magnetic field in voice coil 129 a.
  • Feedback control of the voice-coil actuator in FIG. 1 is accomplished by using fore and aft position sensor coils 135 and 136 .
  • the impedance of coils 135 and 136 change and the impedance change is interpreted as positional change by electronics external to the blood pump 20 .
  • a feedback control algorithm such as virtually zero power control is applied to the position signal to determine the voltage or current applied to the voice coils 129 a and 129 b.
  • the stator housing 81 extends for a large fraction of the length of the blood pump 20 .
  • Stator housing 81 forms the outside wall of annular flow gap 39 , which is a large part of the blood flow path through the pump. Additionally, the stator housing 81 supports the stator PM rings 121 a, 121 b, 121 c, 121 d, the voice coils 129 a, 129 b, the motors coils 126 , and motor iron 125 .
  • Pump 220 includes a hollow housing having an inflow end 237 , an outflow end 238 , and a housing axis 201 extending between these ends.
  • the pump further includes a rotor 260 having a rotor axis 203 , the rotor being disposed within the housing.
  • the rotor includes a first set of cylindrical rotor PM rings 268 a - c disposed adjacent the inflow end 237 of the pump 220 .
  • the first set of rotor PM rings have like magnetic poles of mutually-adjacent rings facing axially toward one another. For example, the north pole of ring 268 a faces toward the north pole of ring 268 b.
  • the south pole of ring 268 b faces toward the south pole of ring 268 c.
  • the first set of rotor PM rings thus cooperatively constitute a first rotor permanent magnet 269 that is symmetrical about the rotor axis 203 , and which has opposite magnetic poles axially spaced apart from one another in an alternating arrangement.
  • a south pole 271 a at the end of the magnet defined by ring 268 a
  • a north pole 271 b at the juncture between rings 268 a and 268 b
  • a south pole 271 c at the juncture of rings 268 b and 268 c
  • a south pole 271 d at the end of the magnet defined by ring 268 c.
  • the rings are of uniform thickness, so that the each pole 271 of magnet 269 is spaced apart from the next adjacent pole of this magnet by a uniform spacing distance DS 1 .
  • the rotor further includes a second set of rotor PM rings 268 d - f , which cooperatively constitute a second rotor permanent magnet 273 disposed adjacent the outflow end 238 of the pump.
  • the second rotor permanent magnet is similar to the first rotor permanent magnet.
  • magnet 273 is symmetrical about the rotor axis 203 and defines poles 275 a - 275 d in alternating north pole and south pole sequence along axis 203 .
  • the mutually-adjacent poles of magnet 273 are spaced apart from one another along the axis by a uniform spacing distance DS 2 .
  • a first set of cylindrical stator PM rings 321 a - c is fixed to the housing 281 of the pump 220 adjacent the inflow end 237 of the housing.
  • the first set of stator rings cooperatively constitutes a first stator permanent magnet 323 .
  • This magnet is tubular and symmetrical about the housing axis 201 and has poles 371 a - 371 d in the same alternating sequence of south and north poles as the first rotor permanent magnet 269 .
  • magnet 323 has a south pole 371 at the end closest to the inflow end 237 of the housing, followed by a north pole 371 b, and so on.
  • Mutually adjacent poles of first stator permanent magnet 323 are spaced apart from one another by the same spacing distance DS 1 as the poles of the first rotor permanent magnet 269 .
  • a second set of stator PM rings 321 d - f is fixed to the housing 281 of the pump 220 adjacent outflow end 238 . These rings cooperatively define a second stator permanent magnet 325 .
  • Magnet 325 is also tubular and symmetrical about the housing axis 201 and has alternating north and south poles 373 a - 373 d in a sequence corresponding to the sequence of poles 275 a - 275 d in the second rotor permanent magnet 273 .
  • Adjacent poles of the second stator permanent magnet 325 are axially spaced from one another at the same spacing distance DS 2 as the poles of the second rotor permanent magnet 273 .
  • stator permanent magnets 323 and 325 is slightly greater than the axial distance between the rotor permanent magnets 269 and 273 .
  • Rotor 260 also has motor permanent magnets schematically depicted at 207 .
  • a set of motor coils 209 is mounted to the housing 281 .
  • the motor magnets and motor coils may be of conventional construction and are arranged to spin the rotor around its axis when the coils are energized by an appropriate drive circuit.
  • the rotor is also equipped with surfaces such as the vanes schematically depicted at 211 , arranged to impel blood in the downstream direction indicated by arrow Q, from the inflow end 237 to the outflow end 238 , upon rotation of the rotor about its axis.
  • first rotor magnet 269 The magnetic interactions between the first rotor magnet 269 and first stator magnet 323 , and between second rotor magnet 273 and second stator magnet 325 , levitate the rotor 260 within the housing 281 in the operating position shown.
  • the rotor axis 203 is coaxial with the housing axis 201 .
  • First rotor PM magnet 269 is largely received within the tubular first stator PM magnet 323 , but the rotor magnet 269 is offset in a first axial direction from the stator magnet by an offset distance DO 1 , so that pole 271 d of the rotor magnet protrudes beyond pole 371 d of the stator magnet.
  • the first axial direction is the downstream direction indicated by arrow Q in FIG.
  • the first offset distance D 01 is less than the spacing distance DS 1 between adjacent poles of the first rotor magnet, and typically D 01 is less than one-half DS 1 .
  • Second rotor magnet 273 is received within second stator magnet 325 , but is offset therefrom by a second offset distance DO 2 in the second axial direction, opposite to the first axial direction.
  • the second rotor magnet is offset from the stator rotor magnet in the upstream direction, opposite to arrow Q in FIG. 2A .
  • the second offset distance D 02 is less than the spacing distance DS 2 between adjacent poles of the first rotor magnet, and typically D 02 is less than one-half DS 2 .
  • FIG. 2B illustrates the interactions between the bearings.
  • the magnetic forces exerted by the poles of the stator magnets on the corresponding poles of the rotor magnets are depicted by the inclined arrows in FIG. 2 .
  • repulsive forces predominate over attractive forces. In the radial direction, the repulsive forces tend to hold each rotor magnet coaxial with the associated stator magnet.
  • the poles of the first rotor magnet 269 are offset in the first axial direction (to the right in FIG.
  • the first stator magnet imparts a first axial force FA 1 on the first rotor magnet 269 and thus on rotor 260 .
  • This axial force is in the first axial direction, and thus in the downstream direction indicated by arrow Q.
  • the second stator magnet 325 imparts a second axial force FA 2 on the second rotor magnet 273 , and thus on rotor 260 in the second axial direction.
  • the rotor permanent magnets 269 , 273 , and stator permanent magnets 323 , 325 tend to keep the rotor 260 not only in radial alignment with the housing 281 of the pump 220 , but also in axial alignment.
  • FIG. 3A shows an alternate embodiment of a blood pump 420 .
  • pump 420 includes first and second sets of rotor PM rings 468 a - c and 468 d - f constituting first and second rotor permanent magnets 402 and 404 on the rotor 460 .
  • Corresponding first and second stator permanent magnets 406 and 408 are formed by first and second sets of stator PM rings 521 a - c and 521 d - f on the housing 481 of the pump 420 .
  • These permanent magnets may have the same configurations as the rotor and stator permanent magnets discussed above.
  • the rotor permanent magnets 402 and 404 are disposed farther from one another than the stator permanent magnets 406 and 408 .
  • offsets between rotor and stator permanent magnets are the reverse of those shown in FIG. 2A .
  • the first rotor permanent magnet 402 is largely received within the first stator permanent magnet 406 , but is offset therefrom by an offset distance DO 1 in a first direction toward the inflow or upstream end 437 of the housing, i.e., to the left as seen in FIG. 3A .
  • the second rotor permanent magnet 404 is largely received within the second stator permanent magnet 408 , but magnet 404 is offset from magnet 408 by an offset distance DO 2 in a second direction, toward the outflow or downstream end 438 of the housing.
  • Pump 420 also includes motor magnets and coils (not shown) for rotating rotor 460 about its axis 401 , as well as surfaces (not shown) on the rotor for impelling blood in a downstream direction toward the outflow end 438 of the housing upon rotation of the rotor.
  • first rotor permanent magnet 402 with first stator permanent magnet 406
  • second rotor permanent magnet 404 with second stator permanent magnet 408
  • Repulsion of first rotor magnet 402 by first stator magnet 406 produces an first axial force FA 1 in the first direction
  • second stator magnet 408 and second rotor magnet 404 apply a second axial force FA 2 in the second, opposite direction on the rotor.
  • these forces balance one another. If the rotor 460 moves in the first direction (toward the inflow end 437 of the pump) from the equilibrium position depicted in FIG.
  • first axial force FA 1 decreases and second axial force FA 2 increases, so that there is a net restoring force in the second axial direction, toward the outflow end 438 of the pump 420 .
  • the opposite effects occur upon movement of the rotor in the second axial direction from the equilibrium position.
  • the rotor is levitated within the housing and maintained in radial and axial position without the use of any other bearings or position control elements.
  • active position control elements such as a voice coil and feedback control circuitry are not used in this embodiment.
  • the pump can be simple and compact.
  • the magnetic bearing arrangements discussed above can be used in conjunction with additional magnetic, hydrodynamic, or other bearings, in conjunction with active position control elements, or both.
  • each of the first and second rotor permanent magnets can be varied.
  • the rotor permanent magnets may be formed from plural discs rather than from plural rings as in the embodiments discussed above.
  • each of the rotor permanent magnets and the stator permanent magnets may be formed as a unitary body of magnetic material with magnetization as required to provide the plural poles of each magnet, rather than from separate rings or discs.
  • the stator permanent magnets may be formed integrally with other elements of the rotor and stator.
  • Patterns of magnetization different from those discussed above can be used in the magnetic bearings as long as the magnets provide radial and axial forces that urge the rotor towards axial and radial equilibrium positions.
  • the arrangement of magnets can be modified so long as one pair of rotor and stator magnets provides an axial force on the rotor in a first direction that decreases upon movement of the rotor in the first direction, whereas another pair of rotor and stator magnets provides an axial force in a second, opposite direction, and that axial force decreases upon movement of the rotor in the second axial direction.
  • the rotor and stator magnets need not be cylindrical, as in the embodiments discussed above. For example, these magnets may be conical or frustoconical.
  • poles of the rotor and stator permanent magnets need not be disposed at uniform spacing distances, and the spacing distances between a rotor permanent magnet need not be the same as the spacing distances between poles of the associated stator permanent magnet. Still further, the magnetic intensity may vary from magnet type to magnet type and, therefore, the specific shape and size may vary from the specific embodiment shown.
  • the bearing arrangements can be used in pumps other than the axial flow pumps depicted herein.
  • the bearing arrangements can be using to support the rotor of a blood pump having radial flow or mixed axial and radial flow.
  • stator permanent magnets are tubular and the rotor permanent magnets are received within the stator permanent magnets.
  • the reverse arrangement can be used.
  • the rotor permanent magnets may be tubular, and the stator permanent magnets may be mounted on the spindle and received within the rotor permanent magnets.

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  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Mechanical Engineering (AREA)
  • Cardiology (AREA)
  • Biomedical Technology (AREA)
  • General Health & Medical Sciences (AREA)
  • Anesthesiology (AREA)
  • Veterinary Medicine (AREA)
  • Hematology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • Public Health (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Electromagnetism (AREA)
  • External Artificial Organs (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
US13/897,107 2012-05-17 2013-05-17 Magnetically suspended pump Abandoned US20130330219A1 (en)

Priority Applications (1)

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US13/897,107 US20130330219A1 (en) 2012-05-17 2013-05-17 Magnetically suspended pump

Applications Claiming Priority (2)

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US201261648289P 2012-05-17 2012-05-17
US13/897,107 US20130330219A1 (en) 2012-05-17 2013-05-17 Magnetically suspended pump

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WO (1) WO2013173751A1 (fr)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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WO2016187057A1 (fr) * 2015-05-15 2016-11-24 Thoratec Corporation Amélioration d'une pompe à sang à écoulement axial
CN107137796A (zh) * 2016-05-16 2017-09-08 北京精密机电控制设备研究所 一种旋转式血泵
US20180028990A1 (en) * 2016-07-28 2018-02-01 Medisieve Ltd. Magnetic Mixer and Method
US10177627B2 (en) 2015-08-06 2019-01-08 Massachusetts Institute Of Technology Homopolar, flux-biased hysteresis bearingless motor
CN109350787A (zh) * 2018-09-25 2019-02-19 中南大学 一种用于轴流式人工心脏内部流场粒子图像测速系统及方法
US10833570B2 (en) 2017-12-22 2020-11-10 Massachusetts Institute Of Technology Homopolar bearingless slice motors
US11065435B2 (en) * 2017-02-28 2021-07-20 Sun Medical Technology Research Corporation Blood pump and blood pump adjusting method
US11273300B2 (en) * 2017-10-04 2022-03-15 Heartware, Inc. Magnetically suspended blood driving piston circulatory assist device
US11368081B2 (en) 2018-01-24 2022-06-21 Kardion Gmbh Magnetic coupling element with a magnetic bearing function
US11421694B2 (en) * 2019-02-01 2022-08-23 White Knight Fluid Handling Inc. Pump having magnets for journaling and magnetically axially positioning rotor thereof, and related methods
DE102021119947A1 (de) 2021-07-30 2023-02-02 NMI Naturwissenschaftliches und Medizinisches Institut an der Universität Tübingen Zahnradpumpe mit Axialkraftkompensationseinrichtung
US11585346B2 (en) * 2017-11-16 2023-02-21 Eagleburgmann Germany Gmbh & Co. Kg Pump assembly, in particular for supplying a slide ring seal assembly
US11754075B2 (en) 2018-07-10 2023-09-12 Kardion Gmbh Impeller for an implantable, vascular support system
US11944805B2 (en) 2020-01-31 2024-04-02 Kardion Gmbh Pump for delivering a fluid and method of manufacturing a pump
US12005248B2 (en) 2018-05-16 2024-06-11 Kardion Gmbh Rotor bearing system

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Cited By (21)

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Publication number Priority date Publication date Assignee Title
CN104162191A (zh) * 2014-09-05 2014-11-26 长治市久安人工心脏科技开发有限公司 一种液磁悬浮轴流式心脏辅助血泵
US11511104B2 (en) 2015-05-15 2022-11-29 Tc1 Llc Axial flow blood pump
WO2016187057A1 (fr) * 2015-05-15 2016-11-24 Thoratec Corporation Amélioration d'une pompe à sang à écoulement axial
US11883641B2 (en) 2015-05-15 2024-01-30 Tc1 Llc Axial flow blood pump
US10780207B2 (en) 2015-05-15 2020-09-22 Tc1 Llc Axial flow blood pump
US10177627B2 (en) 2015-08-06 2019-01-08 Massachusetts Institute Of Technology Homopolar, flux-biased hysteresis bearingless motor
CN107137796A (zh) * 2016-05-16 2017-09-08 北京精密机电控制设备研究所 一种旋转式血泵
US20180028990A1 (en) * 2016-07-28 2018-02-01 Medisieve Ltd. Magnetic Mixer and Method
US10639602B2 (en) * 2016-07-28 2020-05-05 Medisieve Ltd Magnetic mixer and method
US11065435B2 (en) * 2017-02-28 2021-07-20 Sun Medical Technology Research Corporation Blood pump and blood pump adjusting method
US11273300B2 (en) * 2017-10-04 2022-03-15 Heartware, Inc. Magnetically suspended blood driving piston circulatory assist device
US11585346B2 (en) * 2017-11-16 2023-02-21 Eagleburgmann Germany Gmbh & Co. Kg Pump assembly, in particular for supplying a slide ring seal assembly
US10833570B2 (en) 2017-12-22 2020-11-10 Massachusetts Institute Of Technology Homopolar bearingless slice motors
US11368081B2 (en) 2018-01-24 2022-06-21 Kardion Gmbh Magnetic coupling element with a magnetic bearing function
US11804767B2 (en) 2018-01-24 2023-10-31 Kardion Gmbh Magnetic coupling element with a magnetic bearing function
US12005248B2 (en) 2018-05-16 2024-06-11 Kardion Gmbh Rotor bearing system
US11754075B2 (en) 2018-07-10 2023-09-12 Kardion Gmbh Impeller for an implantable, vascular support system
CN109350787A (zh) * 2018-09-25 2019-02-19 中南大学 一种用于轴流式人工心脏内部流场粒子图像测速系统及方法
US11421694B2 (en) * 2019-02-01 2022-08-23 White Knight Fluid Handling Inc. Pump having magnets for journaling and magnetically axially positioning rotor thereof, and related methods
US11944805B2 (en) 2020-01-31 2024-04-02 Kardion Gmbh Pump for delivering a fluid and method of manufacturing a pump
DE102021119947A1 (de) 2021-07-30 2023-02-02 NMI Naturwissenschaftliches und Medizinisches Institut an der Universität Tübingen Zahnradpumpe mit Axialkraftkompensationseinrichtung

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