# US 8,770,945 B2 · Centrifugal pump apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,770,945 B2 - Document ID: US8770945B2 - Status: Granted - Kind: B2 - Application number: 13/254,979 - Filed: 2010-03-01 - Published: 2011-12-29 - Granted: 2014-07-08 - Earliest claimed: 2009-03-06 - Assignees: Thoratec Corporation - Applicants: Takayoshi Ozaki; Hiroyuki Yamada; Kenichi Suzuki; Ken Sugiura - Inventors: Takayoshi Ozaki; Hiroyuki Yamada; Kenichi Suzuki; Ken Sugiura - Web page: https://patentgrep.com/patent/US8770945B2 ## CPC - F04D 25/026: {with a magnetic coupling} - A61M 60/232: Centrifugal pumps - 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 - A61M 60/422: the force acting on the blood contacting member being electromagnetic, e.g. using canned motor pumps - A61M 60/824: Hydrodynamic or fluid film bearings - F04D 13/026: {Details of the bearings} - F04D 13/027: {Details of the magnetic circuit} - F04D 13/0666: {the motor being of the plane gap type} - F04D 17/10: for compressing or evacuating - F04D 29/048: magnetic; electromagnetic - A61M 60/148: in line with a blood vessel using resection or like techniques, e.g. permanent endovascular heart assist devices - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)} ## Abstract In this centrifugal blood pump apparatus, one permanent magnet is provided in one surface of an impeller, a second permanent magnet is provided in an inner wall of a blood chamber, a third permanent magnet is provided in the other surface of the impeller, and a fourth permanent magnet and a rotor for driving the impeller to rotate are provided, with an diaphragm being interposed. An amount of change in attractive force between the first permanent magnet and the second permanent magnet and an amount of change in attractive force between the third and fourth permanent magnets when the impeller is eccentric are made substantially equal to each other. Therefore, a levitation position of the impeller can always be maintained at a substantially central position in a housing. ## Claims ### Claim 1 A centrifugal pump apparatus including a housing having first and second chambers partitioned from each other by a diaphragm, an impeller rotatably provided in said first chamber along said diaphragm, for delivering liquid by centrifugal force during rotation, and a drive unit provided in said second chamber for driving said impeller to rotate, comprising: a first magnetic element provided in one surface of said impeller; a second magnetic element provided in an inner wall of said first chamber facing the one surface of said impeller, for attracting said first magnetic element; and a third magnetic element provided in the other surface of said impeller, during rotation of said impeller, a first attractive force between said first and second magnetic elements and a second attractive force between said third magnetic element and said drive unit being balanced with each other substantially in a center of a movable range of said impeller in said first chamber, and an amount of change in said first attractive force with respect to an amount of eccentricity in a radial direction of said impeller being substantially equal to an amount of change in said second attractive force with respect to the amount of eccentricity in the radial direction of said impeller by adjustment of the second attractive force by modulation of phase of voltages supplied to the drive unit, and a first groove for hydrodynamic bearing being formed in one surface of said impeller or in the inner wall of said first chamber facing the one surface and a second groove for hydrodynamic bearing being formed in the other surface of said impeller or in said diaphragm facing the other surface. ### Claim 2 (depends on 1) The centrifugal pump apparatus according to claim 1, wherein said drive unit includes a rotor rotatably provided along said diaphragm in said second chamber, a fourth magnetic element provided in said rotor, for attracting said third magnetic element, and a motor for rotating said rotor. ### Claim 3 (depends on 2) The centrifugal pump apparatus according to claim 2, wherein an absolute value of a positive supporting rigidity value in the radial direction of a magnetic coupling portion constituted of said first and second magnetic elements is greater than an absolute value of a positive supporting rigidity value in a radial direction of a magnetic coupling portion constituted of said third and fourth magnetic elements. ### Claim 4 (depends on 1) The centrifugal pump apparatus according to claim 1, wherein said third magnetic element includes a plurality of magnets arranged along a single, identical circle such that adjacent magnetic polarities are different from each other, and said drive unit includes a plurality of coils provided to face said plurality of magnets, for generating rotating magnetic field. ### Claim 5 (depends on 4) The centrifugal pump apparatus according to claim 4, wherein said second attractive force is adjusted by varying a phase of a current fed to said plurality of coils. ### Claim 6 (depends on 5) The centrifugal pump apparatus according to claim 5, further comprising a magnetic sensor provided in said second chamber to face said plurality of magnets, wherein a phase of a current fed to said plurality of coils is varied based on an output signal from said magnetic sensor. ### Claim 7 (depends on 1) The centrifugal pump apparatus according to claim 1, wherein said third magnetic element includes a plurality of magnets arranged along a single, identical circle such that adjacent magnetic polarities are different from each other, and said drive unit includes a plurality of fourth magnetic elements provided to face said plurality of magnets, and a plurality of coils provided in correspondence with said plurality of fourth magnetic elements respectively and each wound around the corresponding fourth magnetic element, for generating rotating magnetic field. ### Claim 8 (depends on 7) The centrifugal pump apparatus according to claim 7, wherein said second attractive force is adjusted by varying a phase of a current fed to said plurality of coils. ### Claim 9 (depends on 8) The centrifugal pump apparatus according to claim 8, further comprising a magnetic sensor provided in said second chamber to face said plurality of magnets, wherein a phase of a current fed to said plurality of coils is varied based on an output signal from said magnetic sensor. ### Claim 10 (depends on 1) The centrifugal pump apparatus according to claim 1, comprising: a plurality of said first magnetic elements provided in one surface of said impeller and aligned in a radial direction of said impeller; and a plurality of said second magnetic elements provided in the inner wall of said first chamber facing the one surface of said impeller and attracting said plurality of first magnetic elements respectively, wherein during rotation of said impeller, first attractive force between said plurality of first magnetic elements and said plurality of second magnetic elements and second attractive force between said third magnetic element and said drive unit are balanced with each other substantially in the center of the movable range of said impeller in said first chamber. ### Claim 11 (depends on 10) The centrifugal pump apparatus according to claim 10, wherein at least one magnetic element of said plurality of first magnetic elements and said plurality of second magnetic elements is formed annularly around a rotation centerline of said impeller. ### Claim 12 (depends on 10) The centrifugal pump apparatus according to claim 10, wherein at least one magnetic element of said plurality of first magnetic elements and said plurality of second magnetic elements are formed as multiple pieces annularly around a rotation centerline of said impeller. ### Claim 13 (depends on 10) The centrifugal pump apparatus according to claim 10, wherein each of said plurality of first magnetic elements and said plurality of second magnetic elements is a permanent magnet, and N poles of two first magnetic elements adjacent in said radial direction of said impeller are oriented in an identical direction. ### Claim 14 (depends on 10) The centrifugal pump apparatus according to claim 10, wherein each of said plurality of first magnetic elements and said plurality of second magnetic elements is a permanent magnet, and N poles of two first magnetic elements adjacent in said radial direction of said impeller are oriented in directions different from each other. ### Claim 15 (depends on 10) The centrifugal pump apparatus according to claim 10, wherein an interval between two first magnetic elements adjacent in said radial direction of said impeller is greater than ½ of a movable distance of said impeller in the radial direction in said first chamber. ### Claim 16 (depends on 10) The centrifugal pump apparatus according to claim 10, wherein a plurality of said third magnetic elements are provided, said plurality of third magnetic elements are arranged along a single, identical circle such that adjacent magnetic polarities are different from each other, and said drive unit includes a plurality of coils provided to face said plurality of third magnetic elements, for generating rotating magnetic field. ### Claim 17 (depends on 10) The centrifugal pump apparatus according to claim 10, wherein a plurality of said third magnetic elements are provided, said plurality of third magnetic elements are arranged along a single, identical circle such that adjacent magnetic polarities are different from each other, and said drive unit includes a plurality of fourth magnetic elements arranged to face said plurality of third magnetic elements, and a plurality of coils provided in correspondence with said plurality of fourth magnetic elements respectively and each wound around the corresponding fourth magnetic element, for generating rotating magnetic field. ### Claim 18 (depends on 10) The centrifugal pump apparatus according to claim 10, wherein said drive unit includes a rotor rotatably provided along said diaphragm in said second chamber, a fourth magnetic element provided in said rotor to face said third magnetic element, for attracting said third magnetic element, and a motor for rotating said rotor. ### Claim 19 (depends on 1) The centrifugal pump apparatus according to claim 1, wherein said liquid is blood, and said centrifugal pump apparatus is used for circulating said blood. ### Claim 20 A centrifugal pump apparatus including a housing having first and second chambers partitioned from each other by a diaphragm, an impeller rotatably provided in said first chamber along said diaphragm, for delivering liquid by centrifugal force during rotation, and a control unit for supplying multi-phase drive voltages to coils of a drive unit of the apparatus for driving said impeller to rotate, comprising: a first magnetic element provided in one surface of said impeller; a second magnetic element provided in an inner wall of said first chamber facing the one surface of said impeller, for attracting said first magnetic element; and a third magnetic element provided in the other surface of said impeller, during rotation of said impeller, a first attractive force between said first and second magnetic elements and a second attractive force between said third magnetic element and said drive unit being balanced with each other substantially in a center of a movable range of said impeller in said first chamber, and an amount of change in said first attractive force with respect to an amount of eccentricity in a radial direction of said impeller being substantially equal to an amount of change in said second attractive force with respect to the amount of eccentricity in the radial direction of said impeller by adjustment of the second attractive force by modulation of phase of drive voltages supplied to the coils of the drive unit. ### Claim 21 (depends on 20) The centrifugal pump apparatus according to claim 20, wherein the control unit comprises a motor control circuit and a power amplifier, and wherein the motor control circuit outputs three-phase control signals to the power amplifier and the power amplifier amplifies the three-phase control signals and generates three-phase drive voltages that are supplied to first, second, and third coils of the drive unit for adjustment of the second attractive force during rotation of said impeller.