Iron Ring in Open NMR Magnet System
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Solution Overview
Problem
Current nuclear magnetic resonance (NMR) magnet systems with external supporting means for superconducting coils are bulky, complex, and prone to instability, leading to deformation and quench phenomena due to strong electromagnetic interactions, which increases liquid helium consumption and complicates the magnetic field stabilization.
Innovation Solution
An open-type NMR magnet system utilizing low or high-temperature superconducting wires with ferromagnetic iron yokes and an iron ring structure to form a magnetic circuit, where the iron ring is strategically placed within cryogenic containers to offset electromagnetic forces and reduce magnetic field interaction, supported by non-ferromagnetic materials to maintain stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If external supporting means are used to support superconducting coils, then coil stability is improved, but device volume increases and structure becomes complex
Solution Approach 1:
The iron yoke is integrated with the coil support structure, merging the magnetic circuit function and mechanical support function into a single component. This eliminates the need for separate external supporting means while maintaining coil stability and reducing structural complexity.
Solution Approach 2:
The iron yoke serves multiple functions simultaneously: it provides the magnetic circuit path for the superconducting coils, acts as a structural support for the coils, and provides mechanical strength to withstand electromagnetic forces. This multi-functionality reduces the number of components needed.
2Stability of the object's composition
If external supporting means are used to support superconducting coils, then coil stability is improved, but manufacturing difficulty increases
Solution Approach 1:
By combining the support function into the iron yoke itself, the manufacturing process is simplified. The iron yoke can be manufactured as a single piece or assembled from standard structural components, eliminating the need to manufacture and assemble separate external supporting structures.
3Stability of the object's composition
If strong external supporting means are used, then coil instability from electromagnetic force is reduced, but heat flow into cryogenic system increases
Solution Approach 1:
The support structure uses composite construction with non-magnetic materials (such as aluminum or stainless steel) combined with the iron yoke. These materials have lower thermal conductivity than traditional steel supports, reducing heat flow into the cryogenic system while maintaining mechanical strength to withstand electromagnetic forces.
4Strength
If external supporting means are used, then structure strength is improved, but liquid helium consumption increases
Solution Approach 1:
The use of non-magnetic support materials with lower thermal conductivity reduces heat leakage into the liquid helium bath, thereby reducing evaporation and consumption of liquid helium while maintaining the structural strength needed to support the coils against electromagnetic forces.
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 system achieves a balanced electromagnetic force, reduces the need for external supporting structures, enhances magnetic field stability, and minimizes liquid helium consumption by using a lightweight and compact design, thereby improving imaging efficiency and reducing the risk of coil deformation.
Implementation Method 1
A magnetic flux circuit is formed for magnetic field generated by the superconducting coil, through upper and lower iron yokes and a lateral iron yoke
Implementation Method 2
The upper and lower iron yokes and the lateral iron yoke made of ferromagnetic materials are magnetized by the magnetic field generated by the superconducting coil
Implementation Method 3
Each of the upper and lower portions comprises an annular superconducting coil and a cryogenic container within which the superconducting coil is placed to be subjected to a cryogenic environment so as to achieve superconducting
Implementation Method 4
An electromagnetic force of up to dozens of tons may be generated between upper/lower iron yokes and the symmetrical distributing superconducting coils due to interactions therebetween
Data Source
AI summary
An open type nuclear magnetic resonance magnet system having an iron ring member. A superconducting coil and a superconducting switch form a closed-loop current circuit to generate a magnetic field. The generated magnetic field gains a magnetic flux circuit and executes magnetic field shielding through upper and lower iron yokes and a lateral iron yoke. The magnet system generates a desired magnetic field in a magnet imaging central area via the superconducting coil. To balance the extremely high electromagnetic force between the superconducting coil and the upper and lower iron yokes, an annular iron ring is mounted in a space defined by an inner perimeter wall of in a cryogenic container. The magnetic field distribution between the superconducting coil and the upper and lower iron yokes is changed via the iron ring, so that the electromagnetic interaction force therebetween is reduced.