# US 10,371,152 B2 · Alternating pump gaps > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,371,152 B2 - Document ID: US10371152B2 - Status: Granted - Kind: B2 - Application number: 15/041,987 - Filed: 2016-02-11 - Published: 2016-08-18 - Granted: 2019-08-06 - Earliest claimed: 2015-02-12 - Assignees: Tc1 LLC - Applicants: Tc1 LLC - Inventors: Masamichi Yanai; Shunzhou Yu; Tao Zhang - Web page: https://patentgrep.com/patent/US10371152B2 ## CPC - F04D 13/064: {Details of the magnetic circuit} - 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 - A61M 60/232: Centrifugal pumps - A61M 60/237: the blood flow through the rotating member having mainly axial components, e.g. axial flow pumps - A61M 60/422: the force acting on the blood contacting member being electromagnetic, e.g. using canned motor pumps - A61M 60/538: Regulation using real-time blood pump operational parameter data, e.g. motor current - A61M 60/82: Magnetic bearings - A61M 60/824: Hydrodynamic or fluid film bearings - F04D 13/0646: {the hollow pump or motor shaft being the conduit for the working fluid} - F04D 13/0666: {the motor being of the plane gap type} - F04D 29/047: hydrostatic; hydrodynamic - F04D 29/048: magnetic; electromagnetic - A61M 2205/3334: Measuring or controlling the flow rate - 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 A blood pump system includes a pump housing and an impeller for rotating in a pump chamber within the housing. The impeller has a first side and a second side opposite the first side. The system includes a stator having drive coils for applying a torque to the impeller and at least one bearing mechanism for suspending the impeller within the pump chamber. The system includes a position control mechanism for moving the impeller in an axial direction within the pump chamber to adjust a size of a first gap and a size of a second gap, thereby controlling a washout rate at each of the first gap and the second gap. The first gap is defined by a distance between the first side and the housing and the second gap is defined by a distance between the second side and the pump housing. ## Claims ### Claim 1 A blood pump system, comprising: a pump housing; an impeller for rotating in a pump chamber within the housing; a stator comprising drive coils for applying force to the impeller; a field oriented control (FOC) device for controlling the drive coils; at least one bearing mechanism for suspending the impeller within the pump chamber; a sensing circuit for determining an axial position of the impeller; and a position control mechanism for moving the impeller in an axial direction between a first eccentric position and a second eccentric position within the pump chamber by controlling, based on the axial position of the impeller, a stator coil flux current provided to the FOC device, independent of a quadrature current provided by a speed control device to the FOC device to control a torque applied to the impeller. ### Claim 2 (depends on 1) The blood pump system of claim 1, wherein: the position control mechanism is configured to move the impeller based on a triggering event. ### Claim 3 (depends on 1) The blood pump system of claim 1, wherein: the position control mechanism is configured to move the impeller based on the impeller crossing a speed threshold. ### Claim 4 (depends on 3) The blood pump system of claim 3, wherein: the speed threshold is a low speed threshold. ### Claim 5 A blood pump system, comprising: a pump housing; an impeller for rotating in a pump chamber within the housing; a stator comprising drive coils for applying force to the impeller; a field oriented control (FOC) device for controlling the drive coils; a first bearing for suspending the impeller relative to a first end of the pump chamber, a first blood gap defined between the impeller and a first bearing surface; a second bearing for suspending the impeller relative to a second end of the pump chamber, a second blood gap defined between the impeller and a second bearing surface; a sensing circuit for determining an axial position of the impeller; and a position control mechanism for moving the impeller in an axial direction between a first eccentric position and a second eccentric position within the pump chamber by controlling, based on the axial position of the impeller, a stator coil flux current provided to the FOC device, independent of a quadrature current provided by a speed control device to the FOC device to control a torque applied to the impeller. ### Claim 6 (depends on 5) The blood pump system of claim 5, wherein: the position control mechanism is configured to move the impeller based on the impeller crossing a speed threshold. ### Claim 7 (depends on 5) The blood pump system of claim 5, wherein: the sensing circuit is configured to: receive two measured currents corresponding to a first phase and a second phase of the drive coils; calculate a current corresponding to a third phase of the drive coils; and estimate the axial position of the impeller. ### Claim 8 (depends on 5) The blood pump system of claim 5, wherein: the position control mechanism is configured to move the impeller based on a triggering event. ### Claim 9 (depends on 8) The blood pump system of claim 8, wherein: the triggering event comprises an impeller speed threshold or a time threshold. ### Claim 10 (depends on 5) The blood pump system of claim 5, wherein: the position control mechanism is configured to move the impeller in the axial direction to reduce the first blood gap and to increase the second blood gap thereby increasing a washout rate at the second blood gap. ### Claim 11 A method of operating a blood pump including a housing and an impeller for rotating within a pump chamber within the housing, comprising: rotating the impeller within the pump chamber with a stator, the impeller being suspended within the pump chamber by a first bearing at a first end of the pump chamber and a second bearing at a second end of the pump chamber; and moving the impeller in an axial direction between a first eccentric position and a second eccentric position within the pump chamber by engaging a position control mechanism which controls a stator coil flux current provided to a field oriented control (FOC) device controlling drive coils of the stator, independent of a quadrature current provided to the FOC device to control a torque applied to the impeller. ### Claim 12 (depends on 11) The method of operating a blood pump including a housing and an impeller for rotating within a pump chamber within the housing of claim 11, wherein: moving the impeller comprises adjusting a magnetic flux between the impeller and the drive coils. ### Claim 13 (depends on 11) The method of operating a blood pump including a housing and an impeller for rotating within a pump chamber within the housing of claim 11, wherein: the method further comprises: receiving two measured currents corresponding to a first phase and a second phase of the drive coils; calculating a current corresponding to a third phase of the drive coils; and estimating an axial position of the impeller; and wherein controlling the stator coil flux current is based on the axial position of the impeller. ### Claim 14 (depends on 11) The method of operating a blood pump including a housing and an impeller for rotating within a pump chamber within the housing of claim 11, wherein moving the impeller comprises: moving the impeller periodically and intermittently. ### Claim 15 (depends on 11) The method of operating a blood pump including a housing and an impeller for rotating within a pump chamber within the housing of claim 11, wherein moving the impeller comprises: moving the impeller based on a triggering event. ### Claim 16 (depends on 15) The method of operating a blood pump including a housing and an impeller for rotating within a pump chamber within the housing of claim 15, wherein: the triggering event comprises an impeller speed threshold or a time threshold.