Disposable Centrifugal Blood Pump Magnetic Coupling Design
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Solution Overview
Problem
Existing disposable centrifugal blood pumps with magnetic coupling face issues such as high magnetic resistance, complex rotor structures, increased manufacturing costs, and heat generation due to the use of multiple permanent magnets, leading to durability problems and limited usage duration.
Innovation Solution
A disposable centrifugal blood pump design featuring a cylindrical rotor with ring-shaped pole faces and a stator with electromagnets for magnetic coupling, utilizing a minimal number of permanent magnets and a Halbach type permanent magnet array for torque transmission, with a motor positioned apart from the housing to prevent heat transfer to the blood.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple permanent magnets are used for the rotor, then magnetic coupling torque is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines multiple permanent magnets into a single integrated rotor assembly where the magnets are arranged in alternating polarity patterns on the rotor surface. This merging approach maintains the necessary magnetic coupling torque while simplifying the overall rotor structure and reducing manufacturing complexity compared to using separate magnet assemblies.
2Power
If permanent magnets are used in high ratio in magnetic circuit, then magnetic coupling is improved, but magnetic resistance increases
Solution Approach 1:
The patent applies local quality by creating alternating N and S pole regions on the rotor surface with specific geometric patterns. This local differentiation of magnetic polarity allows for optimized magnetic flux distribution that maintains strong coupling while reducing overall magnetic resistance through strategic placement of magnetic materials in specific zones rather than uniform distribution.
3Power
If coil current is increased for motor and magnetic suspension, then magnetic coupling is improved, but heat generation increases
Solution Approach 1:
The patent replaces the conventional approach of using high coil current for magnetic suspension with a passive magnetic bearing system utilizing permanent magnets. This substitution eliminates the need for continuous high-current coil operation, thereby maintaining strong magnetic coupling while dramatically reducing heat generation from resistive losses in the coils.
4Force
If permanent magnets are used for torque transmission, then torque transmission is improved, but manufacturing cost and structure complexity increase
Solution Approach 1:
The patent designs the rotor structure to serve multiple functions: the same permanent magnets that provide magnetic coupling also enable torque transmission. This multi-functionality eliminates the need for separate torque transmission mechanisms, thereby reducing manufacturing costs and structural complexity while maintaining effective torque transmission capability.
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
This design reduces magnetic resistance, power consumption, and manufacturing costs, while preventing blood coagulation and extending the usage duration of disposable parts by ensuring a simple, reliable, and cost-effective structure.
Implementation Method 1
the stator includes three or more electromagnets for electromagnetic coupling being arranged around the housing at regular intervals and having pole faces opposed to the pole faces projected from the outer peripheral surface of the rotor, the electromagnets generating a magnetic coupling between the stator and the rotor
Implementation Method 2
a torque transmission disk formed by sandwiching a ring-shaped permanent magnet magnetized in the direction of thickness between two upper and lower ring members formed of magnetic material... for generating a magnetic coupling between the stator and the rotor
Data Source
AI summary
A disposable centrifugal blood pump with magnetic coupling provides a centrifugal blood pump with magnetic coupling which is simple in structure of disposalable parts with low cost. Therefore, a housing as the disposable part includes a rotor having pole faces extending on the outer-peripheral surface and projecting inward from the inner-peripheral surface and an impeller attached to the rotor, and a stator as a reusable part includes three or more electromagnets for electromagnetic coupling for forming a magnetic coupling between the stator and the rotor, a torque transmission disk formed by sandwiching a ring-shaped permanent magnet between two upper and lower ring members and having pole faces corresponding to the pole faces projecting from the inner-peripheral surface of the rotor formed to project for generating a magnetic coupling between stator and rotor, a motor for rotating the torque transmission disk, and a displacement gauge for measuring displacement of the rotor.