Disposable Maglev Pump Rotor Using Electromagnetic Bearings
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Solution Overview
Problem
The use of neodymium permanent magnets in magnetically-levitated centrifugal pumps is costly due to limited supply and high production costs, and the fabrication of impellers with only magnetic materials results in low rigidity and difficulty in integration through injection molding.
Innovation Solution
A magnetically-levitated centrifugal pump design that replaces permanent magnets with a rotor made of magnetic material, using electromagnets for magnetic coupling and a torque transmission disc with ring-shaped permanent magnets to achieve stable magnetic levitation without contact, allowing for inexpensive production and improved processing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If neodymium permanent magnets are used in the disposable impeller section to achieve magnetic levitation, then the magnetic bearing stiffness is sufficient, but the production cost increases significantly and supply is controlled by China
Solution Approach 1:
The patent applies the disposable principle by using a reusable rotor with electromagnetic bearings in the pump head section, while the impeller section is designed as a disposable component. This allows the expensive magnetic bearing system to be reused across multiple impeller sections, significantly reducing the cost per disposable pump unit while maintaining reliable magnetic levitation performance.
Solution Approach 2:
The pump is divided into two main segments: a reusable pump head section containing the rotor and electromagnetic bearings, and a disposable impeller section. This segmentation allows the expensive magnetic bearing system to be separated from the disposable components, enabling cost reduction while maintaining performance.
2Ease of manufacture
If only magnetic materials are used for the rotor to reduce cost, then the production cost decreases, but the rigidity to support the impeller becomes insufficient
Solution Approach 1:
The rotor is constructed using composite materials, specifically a non-magnetic base material (such as plastic or aluminum) combined with magnetic material components. This composite structure provides both the cost advantage of non-magnetic materials and the necessary rigidity and magnetic properties for supporting the impeller and enabling electromagnetic bearing operation.
Solution Approach 2:
Magnetic material is applied locally at specific positions on the rotor where it is most needed for magnetic coupling with the electromagnetic bearings, rather than using magnetic material throughout the entire rotor. This localized application maintains necessary magnetic properties while reducing overall cost and weight.
3Ease of manufacture
If neodymium magnets are embedded in the impeller formed by injection molding, then the impeller can be integrated, but the low demagnetization temperature of neodymium causes formation issues at injection resin temperature
Solution Approach 1:
The impeller section is designed as a disposable component that does not require embedding permanent magnets. Instead, the reusable rotor in the pump head section contains the electromagnetic bearings, eliminating the need for high-temperature magnet embedding in the disposable impeller and avoiding demagnetization issues during injection molding.
Solution Approach 2:
The electromagnetic bearing system acts as an intermediary, transferring the magnetic levitation function from the disposable impeller to the reusable rotor. This allows the impeller to be manufactured without permanent magnets while maintaining the magnetic levitation capability through the electromagnetic bearing interface.
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
The solution enables cost-effective production of disposable pump sections with improved rigidity and reduced risk of heat-induced hemolysis and blood clot formation, while maintaining the stability and torque transmission of magnetically-levitated systems.
Implementation Method 1
The torque transmission disc is configured to magnetically couple with the rotor
Implementation Method 2
magnetically-levitated centrifugal pump
Implementation Method 3
The stator has at least three electromagnets for magnetic bearing at regular intervals. The at least three electromagnets magnetically couple with the rotor.
Data Source
AI summary
A magnetically-levitated centrifugal pump comprises a pump head section and a pump section, where the pump section comprises a stator, a torque transmission disc, a motor, a displacement sensor, and a pump housing.