Magnetic Heart Pump Bearing for Passive Axial Flow Balancing
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Solution Overview
Problem
Existing heart pumps face challenges in independently controlling and balancing the outflow from the left and right sides, requiring complex sensing techniques and excessive electrical power consumption, and have limited ability to accommodate physiological changes, restricting patient activity.
Innovation Solution
A heart pump design featuring a housing with an impeller and magnetic bearing system, utilizing permanent drive magnets and coils to rotate the impeller, and U-shaped bearing stators with tapered legs to control axial and radial positions, allowing independent control of flow without complex sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If active control with feedback signals from pressure sensors is used to axially displace the rotating impeller, then the ability to independently control and balance outflow from left and right sides is improved, but electrical power consumption increases excessively and long term reliability deteriorates due to blood contacting sensors
Solution Approach 1:
The pump housing is designed with a tilted floor that passively guides the impeller to different axial positions based on the volume of blood in the chamber, eliminating the need for active sensors and control systems. The system serves itself by using the blood volume and gravity to automatically position the impeller for optimal outflow control.
Solution Approach 2:
The complex active control system with pressure sensors and feedback signals is extracted and removed from the design. Instead, a simple passive geometric feature (the tilted floor) is used to achieve the same control function without the problematic sensing and active control components.
2Ease of operation
If active control with feedback signals from pressure sensors is used to axially displace the rotating impeller, then the ability to independently control and balance outflow from left and right sides is improved, but device complexity increases due to complex sensing techniques
Solution Approach 1:
The complex active control system with pressure sensors and feedback signals is extracted and removed from the design. Instead, a simple passive geometric feature (the tilted floor) is used to achieve the same control function without the problematic sensing and active control components.
Solution Approach 2:
The pump housing is designed with a tilted floor that passively guides the impeller to different axial positions based on the volume of blood in the chamber, eliminating the need for active sensors and control systems. The system serves itself by using the blood volume and gravity to automatically position the impeller for optimal outflow control.
3Reliability
If traditional pump design with steep pump curve is used, then flow-limiting characteristics are improved to protect physiological system, but ability to accommodate physiological changes deteriorates, restricting patient activity
Solution Approach 1:
The impeller's axial position is dynamically adjusted based on blood volume in the chamber, allowing the pump to adapt its characteristics to changing physiological conditions. The tilted floor enables automatic repositioning that maintains flow-limiting safety characteristics while accommodating varying patient needs and activity levels.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient and power-efficient operation by balancing magnetic forces, reducing power consumption, and accommodating physiological changes, enhancing patient activity without the need for complex sensing.
Implementation Method 1
a plurality of circumferentially spaced drive coils mounted within the housing proximate a first end of the cavity, each coil being wound on a respective drive stator pole of a drive stator and being substantially radially aligned with the drive magnets, the drive coils being configured to generate a drive magnetic field that cooperates with the drive magnets to thereby rotate the impeller
Implementation Method 2
at least one bearing coil on each bearing stator that generates a magnetic field that cooperates with the magnetic bearing members to thereby at least one of: (1) control an axial position of the impeller; and, (2) at least partially restrain radial movement of the impeller
Data Source
Figure 1A~1B
Figure 1C
Figure 1D
AI summary
A heart pump including a housing defining a cavity including at least one inlet aligned with an axis of the cavity and at least one outlet provided in a circumferential outer wall of the cavity. An impeller is provided within the cavity, the impeller including a rotor and vanes mounted on the rotor for urging fluid from the inlet radially outwardly to the outlet. A drive is provided for rotating the impeller in the cavity, the drive including a plurality of circumferentially spaced permanent drive magnets mounted within and proximate a first face of the rotor, adjacent drive magnets having opposing polarities and a plurality of circumferentially spaced drive coils mounted within the housing proximate a first end of the cavity, each coil being wound on a respective drive stator pole of a drive stator and being substantially radially aligned with the drive magnets, the drive coils being configured to generate a drive magnetic field that cooperates with the drive magnets to thereby rotate the impeller. A magnetic bearing is also provided to thereby at least one of control an axial position of the impeller and at least partially restrain radial movement of the impeller.