Dry-Cooled MR Magnet Coil Autonomous Charging Without Quench Risk
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Solution Overview
Problem
Existing methods for charging superconducting MR magnet coil systems in magnetic resonance imaging (MRI) scanners require manual intervention by skilled personnel, are time-consuming, and prone to errors, especially in cryogen-free systems, which lack a temperature buffer and are susceptible to cooling system failures.
Innovation Solution
An autonomous method for charging superconducting MR magnet coil systems using an electronic control unit that monitors temperature and pressure, allowing fully automatic charging by comparing measured values with predefined setpoints, and includes thermal overshoot to optimize current distribution, reducing the need for manual intervention and enhancing safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual charging procedure is used, then safety and precision can be maintained through skilled personnel intervention, but operation time increases and autonomous operation capability deteriorates
Solution Approach 1:
The system enables autonomous charging by having the control unit automatically monitor temperature, compare it with setpoints, control cooling system activation, and regulate charging current without manual intervention. The charging system serves itself by integrating all control functions into an automated sequence that operates independently once initiated.
Solution Approach 2:
The control unit continuously monitors the temperature of the superconducting coil and uses this feedback to determine when to activate cooling and when to begin charging. The system adjusts charging current based on real-time temperature measurements, creating a closed-loop control system that ensures safe autonomous operation.
2Reliability
If cooling system is made more reliable with temperature buffer (cryogen), then temperature stability improves, but system complexity and operational costs increase
Solution Approach 1:
The patent removes the cryogen (temperature buffer) from the system, transitioning from a bath-cooled design to a dry-cooled design. This extraction eliminates the need for large quantities of liquid helium and nitrogen, simplifies the cooling system, and enables autonomous operation while maintaining temperature stability through active cooling control.
Solution Approach 2:
The passive thermal buffer provided by cryogen is replaced with an active electronic control system that uses temperature sensors, control logic, and regulated cooling to maintain temperature stability. This substitution enables more precise temperature control and simplifies system operation.
3Productivity
If charging current is increased to reduce charging time, then productivity improves, but risk of thermal stress and quenching increases
Solution Approach 1:
The charging current is dynamically adjusted based on real-time temperature measurements. The control unit regulates the charging current to increase when temperature is stable and decrease when thermal stress risk increases, creating an adaptive charging process that optimizes speed while preventing quenching.
Solution Approach 2:
The cooling system is activated in advance and maintained during the charging process to pre-establish thermal conditions that can accommodate higher charging currents. This preliminary cooling action enables faster charging by ensuring the system is thermally prepared to handle increased current loads.
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
Enables safe, efficient, and rapid charging of superconducting magnets without manual intervention, reducing downtime and costs, and ensuring reliable operation by preventing quenching and thermal stress.
Implementation Method 1
a cooling arm of a cold head is arranged at least partially in the neck tube, and wherein the superconducting MR magnet coil system is cooled to a superconducting temperature
Implementation Method 2
measuring the electrical current I coil currently flowing in the MR magnet coil system and comparing I coil with a predefinable first current setpoint I1 target, at which the MR magnet coil system generates a desired magnetic field strength
Data Source
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AI summary
An operating method for a magnetic resonance (="MR") apparatus (10) with a cryogen-free super-conductive MR magnet coil system (12) is characterised by the following steps for autonomous electrical charging of the super-conductive MR magnet coil system: (a1) initiating a cooling operation of the coil system; (a2) initiating an automatic current charging program; (b1) measuring the actual temperature Tcoil on the coil system and comparing Tcoil with a predefinable first temperature setpoint value T1ramp as of which the coil system is super-conductive and should be charged; (b2) if Tcoil ≤ T1ramp: supplying a charging current to the coil system and charging the coil system with electric current; (c) measuring the electric current Icoil currently flowing in the coil system and comparing Icoil with a predefinable first current setpoint value I1target at which the coil system generates a desired magnetic field strength; (d) repeating steps (b1), (b2) and (c) until Icoil = I1target; (e) deactivating the current supply to the coil system and stopping the automatic current charging program. The magnet coil system can thus be autonomously charged with electric current.