Superconductive Magnet Shield Coil Positioning
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Solution Overview
Problem
Conventional superconductive magnets face increased material and machining costs, weight, and cooling requirements due to the rising electromagnetic forces needed for higher magnetic field intensities, which complicates the design and operation of MRI, NMR, and monocrystal pulling systems.
Innovation Solution
The superconductive magnet design incorporates a first group of main coils and a second group of shield coils arranged coaxially with optimized positions to balance and cancel out axis-direction electromagnetic forces, reducing the amount of materials and machining costs by positioning the shield coils between 0.63 to 0.87 of the main coil's axis-direction coordinate, thereby minimizing the electromagnetic force exerted on the shield coils and the amount of superconductive wires used.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the magnetic field intensity is increased to meet higher performance requirements, then the magnetic field generation capability is improved, but the electromagnetic force increases causing greater material and machining costs
Solution Approach 1:
The patent optimizes the Z-coordinate position parameter of the shield coil relative to the main coil, positioning it within the range of 0.63 to 0.87 times the main coil's axis-direction coordinate. This parameter change reduces the electromagnetic force acting on the shield coil while maintaining the desired magnetic field intensity, thereby reducing material and machining costs.
2Object-generated harmful factors
If the shield coil is positioned farther from the magnetic-field generation region to reduce leakage magnetic field, then the leakage magnetic field is reduced, but the electromagnetic force on the shield coil increases
Solution Approach 1:
The patent determines the optimal Z-coordinate position of the shield coil as 0.63 to 0.87 times the axis-direction coordinate of the main coil. This optimized parameter positioning simultaneously achieves effective leakage magnetic field reduction and minimizes the electromagnetic force acting on the shield coil, resolving the contradiction between these two requirements.
3Ease of manufacture
If the amount of superconductive wires is reduced to lower cost, then the manufacturing cost is reduced, but the magnetic field homogeneity and intensity may be compromised
Solution Approach 1:
By optimizing the shield coil's Z-coordinate position to 0.63-0.87 times the main coil's coordinate, the patent reduces the electromagnetic force on the shield coil, allowing for reduced superconductive wire quantity while maintaining magnetic field homogeneity and intensity requirements, thus lowering manufacturing cost without sacrificing performance.
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 configuration reduces the weight and material requirements of the magnet, lowers the costs of production and cooling, and achieves a more efficient use of superconductive materials while maintaining the desired magnetic field intensity and homogeneity, thus addressing the challenges of increased electromagnetic forces.
Implementation Method 1
a shield coil 3 for cancelling out a magnetic field that leaks outside the main coil 2. The shield coil 3 is a coil for generating a magnetic field that is opposite the magnetic field generated by means of the main coil 2
Implementation Method 2
it is required to apply a large current of several hundreds amperes to the superconductive coil. As a result, a high magnetic field is generated in the vicinity of each of the superconductive coils; therefore, large electromagnetic force is exerted on the superconductive coil
Implementation Method 3
heat is produced in the outer surface or the inside of the coil; this heat may cause a so-called quench phenomenon in which the superconductive state is destructed and transits to a normal conductive state
Data Source
AI summary
There is obtained a superconductive magnet in which there are reduced the machining costs and the amount of materials for bobbins and supporting members that support coils. In a superconductive magnet provided with a first group of coils serving as main coils for generating a magnetic field and a second group of coils serving as shield coils that are arranged coaxially with the first group of coils and generate a magnetic field whose direction is opposite the direction of a magnetic field generated by the first group of coils so that a magnetic field that leaks outside is cancelled, the second group of coils are arranged at axis-direction positions where axis-direction electromagnetic force generated by the first group of coils and exerted on the second group of coils and axis-direction electromagnetic force generated by the second group of coils balance with each other and cancel out each other.