Magnetically Geared Drive for Sealed Systems
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Solution Overview
Problem
Existing drive systems for pumps and turbines face challenges in achieving efficient speed ratios and maintaining hermetic seals to prevent fluid contamination, particularly when the power source operates at different speeds from the driven mechanism.
Innovation Solution
A magnetically geared system using rotors with permanent magnets and ferromagnetic pole pieces to create a spatially varying magnetic field, allowing for geared rotation without mechanical coupling, and embedding pole pieces within the housing to maintain efficient coupling and prevent fluid contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hermetic seal is used to prevent fluid contamination, then fluid sealing is improved, but mechanical coupling between drive and driven mechanisms becomes complex
Solution Approach 1:
The patent replaces mechanical coupling with magnetic coupling between the drive shaft and driven mechanism. Permanent magnets on the drive shaft interact with ferromagnetic pole pieces on the driven mechanism through a hermetic barrier, eliminating the need for mechanical penetrations while maintaining torque transmission. This resolves the contradiction by substituting magnetic fields for mechanical connections across the seal boundary.
Solution Approach 2:
The hermetic barrier acts as an intermediary element that allows magnetic field transmission while preventing fluid contamination. The magnetic coupling system transmits rotational motion and torque through the barrier without requiring physical contact, maintaining both sealing integrity and drive functionality.
2Speed
If the power source operates at different speed from the driven mechanism, then speed adaptation is improved, but mechanical gearing increases complexity
Solution Approach 1:
The patent replaces mechanical gearing with magnetic pole interaction to achieve speed adaptation. By configuring permanent magnets and ferromagnetic pole pieces with specific pole counts, the system achieves gear-like speed reduction or multiplication without physical gears. The magnetic coupling inherently provides the speed ratio through the interaction of magnetic fields with different pole configurations.
3Speed
If mechanical gearing is used to achieve speed ratios, then speed adaptation is improved, but mechanical losses and turbulence increase
Solution Approach 1:
The patent eliminates mechanical gear contacts by using magnetic field interaction for speed ratio achievement. The permanent magnets and ferromagnetic pole pieces couple magnetically across a small air gap, transmitting torque without sliding friction or impact losses associated with mechanical gearing. This reduces mechanical losses and turbulence while maintaining effective speed adaptation.
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 magnetic gearing system achieves efficient speed ratios and prevents fluid contamination by inducing rotation in the driven rotor at a different speed, reducing mechanical losses and turbulence, and allowing for hermetic operation in sealed systems.
Implementation Method 1
The first rotor (102) comprises a support (108) carrying a first set of permanent magnets (110), arranged to produce a spatially varying magnetic field with a number of magnetic poles. The second rotor (104) comprises a support (112) carrying a second set of permanent magnets (114), arranged to produce a spatially varying magnetic field with a different number of poles
Implementation Method 2
The interaction between the two fields is controlled by a number of pole pieces (106) of ferromagnetic material, used to control the way in which the fields of the permanent magnets (110, 114) interact
Data Source
AI summary
A drive for a sealed magnetically geared system comprising a housing defining a sealed chamber, a driving member including a first set of magnets, and a driven member comprising a second set of magnets, one of the members being located inside the chamber, wherein the first and second sets of magnets are arranged to produce different numbers of magnetic poles, and the housing includes a wall extending between the members and supporting a plurality of pole pieces which are arranged to modulate the magnetic field acting between the magnets.