Two-Stage Superconducting Magnet Quench Using EMI Shielding Coil
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Solution Overview
Problem
Current MRI system quenching methods, such as internal heaters and vacuum puncture, are prone to failure and pose safety risks due to potential unavailability, maintenance issues, and equipment damage.
Innovation Solution
A two-stage quenching system incorporating a primary coil assembly and an EMI shielding coil assembly with a variable resistor that generates heat when a magnetic flux exceeds a critical current, causing the primary coil assembly to quench, utilizing a ferrous object to create the necessary magnetic flux without physical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If internal heater or vacuum puncture methods are used for quenching, then the magnetic field can be removed, but the system reliability decreases and safety risks increase
Solution Approach 1:
The EMI shielding coil assembly serves a dual function: it provides electromagnetic interference shielding during normal operation and acts as the quenching mechanism when needed. By utilizing the existing shielding coil and introducing a ferrous object to generate magnetic flux, the system quenches itself without requiring separate active components like heaters or vacuum systems, thereby improving reliability and reducing safety risks
Solution Approach 2:
A ferrous object is introduced as an intermediary to generate magnetic flux that induces current in the EMI shielding coil assembly. This indirect method of quenching avoids direct contact with the primary coil assembly and eliminates the need for complex quenching equipment, making the system more reliable and safer to operate
2Ease of operation
If active quenching components (heaters, vacuum systems) are installed, then quenching capability is provided, but device complexity increases
Solution Approach 1:
The EMI shielding coil assembly is designed to perform multiple functions: it provides electromagnetic interference shielding during normal MRI operation and serves as the quenching mechanism when needed. This multi-functionality eliminates the need for separate dedicated quenching components, significantly reducing device complexity while maintaining ease of operation
Solution Approach 2:
The system uses its own EMI shielding infrastructure to perform the quenching function. By introducing a ferrous object that generates magnetic flux to induce current in the shielding coil, the system achieves quenching through its existing components rather than requiring additional active quenching equipment
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 method provides a reliable, efficient, and cost-effective means to quench the MRI system in emergency situations, reducing the risk of equipment damage and ensuring safety by using existing components and simple ferrous objects for flux generation.
Implementation Method 1
The variable resistor is configured to be superconducting when conducting current below a third critical current and to be non-superconducting when conducting current at or above the third critical current. Generating a magnetic flux within the EMI shielding coil assembly causes the current conducted through the variable resistor to exceed the third critical current, quenching the variable resistor and generating heat.
Implementation Method 2
The system is configured such that positioning a ferrous object with a magnetic moment in proximity to the EMI shielding coil assembly generates the magnetic flux within the EMI shielding coil assembly.
Data Source
AI summary
A superconducting magnet system having two-stage quenching. A primary coil assembly includes a coil section configured to be superconducting when conducting current below a first critical current. An EMI shielding coil assembly includes a coil section configured to be superconducting when conducting current below a second critical current, which is electrically coupled to a variable resistor configured to be superconducting when conducting current below a third critical current and to be non-superconducting when conducting current at or above the third critical current that is less than both the first and second critical currents. Generating a magnetic flux within the EMI shielding coil assembly causes the current conducted through the variable resistor to exceed the third critical current, quenching the variable resistor and generating heat. The EMI shielding coil assembly is disposed such that the heat from the variable resistor quenches the primary coil assembly.