Magnetic Pump Rotor Geometry for Higher Axial Levitation Stiffness
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Solution Overview
Problem
Electromagnetic rotary drives with internal rotors in centrifugal pumps have relatively low axial stiffness due to low magnetic flux density in the air gap between the stator and rotor, limiting their stability and efficiency in applications requiring high purity and gentle handling of substances.
Innovation Solution
Designing an electromagnetic rotary drive with a ring-shaped or disk-shaped magnetically effective core, where the rotor height exceeds the stator pole height, concentrating magnetic flux and increasing axial stiffness, while maintaining tilting stiffness through optimized geometric ratios and edge region designs, such as truncated cones or spherical disks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotor height is increased to concentrate magnetic flux and improve axial stiffness, then the axial stability of magnetic levitation is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies parameter changes by modifying the rotor height dimension to be greater than the stator pole height, which concentrates magnetic flux in the air gap and increases axial stiffness. This dimensional parameter change directly improves axial stability while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent utilizes the axial dimension by extending the rotor height beyond the stator pole height, creating a three-dimensional magnetic flux concentration effect. This dimensional approach enhances axial stiffness without requiring complex modifications to the radial or circumferential structures.
2Reliability
If the rotor height exceeds the stator pole height to concentrate magnetic flux, then axial stiffness is enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
By changing the rotor height parameter to exceed the stator pole height, the patent creates a geometric configuration that naturally concentrates magnetic flux. This parameter change improves axial stiffness while the geometric design itself provides guidance for manufacturing alignment.
Solution Approach 2:
The patent creates a symmetric geometric relationship where the rotor height exceeds stator pole height uniformly, establishing an equipotential magnetic field distribution that reduces sensitivity to manufacturing variations and simplifies alignment requirements.
3Volume of moving object
If the rotor is designed as an integral rotor for compact design, then space utilization is improved, but the flexibility for separation and replacement is reduced
Solution Approach 1:
The patent designs the rotor as an integral multi-functional component that serves both as the electromagnetic rotor and as a pump impeller. This universal design achieves compactness while allowing the entire rotor assembly to be replaced as a single unit, maintaining flexibility for single-use applications.
Solution Approach 2:
The patent merges the rotor function with the pump impeller function into a single integral component. This combination reduces overall device volume and simplifies the structure, while the modular pump assembly allows for easy separation and replacement of the rotor-impeller unit from the stator.
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
Significantly enhances the axial stiffness of magnetic levitation and stabilization, improving the rotor's ability to handle axial deflections and tilting, thus enhancing the overall performance and reliability of the centrifugal pump in sensitive applications.
Implementation Method 1
A magnetic rotating field can be generated with the electrical windings of the stator, which on the one hand exerts a torque on the rotor, which effects its rotation about a desired axis of rotation
Implementation Method 2
which, on the other hand, exerts a shear force, which can be set as desired, onto the rotor so that its radial position can be actively controlled or regulated
Implementation Method 3
exerts a shear force onto the rotor
Implementation Method 4
the rotor is passively magnetically levitated or stabilized by reluctance forces
Data Source
AI summary
An electromagnetic rotary drive includes a rotor including a magnetically effective core surrounded by a stator. The stator has poles arranged around the magnetically effective core and each of the poles is delimited by an end face. The rotor is capable of being magnetically driven without contact in an operating state about an axial direction, and is capable of being magnetically levitated without contact with respect to the stator. The rotor is configured to be magnetically levitated in a radial plane and is passively magnetically stabilized in the axial direction against tilting. The magnetically effective core has a rotor height which is a maximum extension of the magnetically effective core in the axial direction, the rotor height being greater than a stator pole height defined by a maximum extension of the end faces in the axial direction.