Autonomous Cooling Control for Dry-Cooled Superconductive MR Coils
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Solution Overview
Problem
Current methods for cooling superconductive MR magnetic coil systems in MRI and NMR devices require technical specialists and are not autonomous, as they need manual intervention for preliminary cooling from room temperature to cryogenic temperatures, especially after system installation or in case of quench events.
Innovation Solution
A method and apparatus that use a control unit to autonomously manage temperature and pressure parameters, activating a vacuum pump and cold head to create a vacuum and cool the system to cryogenic temperatures, allowing for independent operation without specialized personnel, using sensors to monitor and adjust vacuum and cooling processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If manual cooling by technical specialists is used, then the cooling process can be performed, but the system requires specialized personnel and cannot operate autonomously
Solution Approach 1:
The system is equipped with temperature sensors, pressure sensors, and a control unit that automatically monitor system parameters and control the vacuum pump and cold head without human intervention. The control unit receives temperature values from sensors and autonomously activates cooling components when thresholds are exceeded, enabling the system to service itself
Solution Approach 2:
Temperature sensors continuously monitor the magnetic coil system temperature and provide feedback to the control unit. The control unit processes this feedback and automatically adjusts cooling operations based on the measured temperature values, creating a closed-loop control system that operates autonomously
2Loss of time
If preliminary cooling from room temperature is performed manually, then the system can reach cryogenic temperatures, but the process requires technical specialists and increases downtime
Solution Approach 1:
The control unit is pre-programmed with temperature thresholds and cooling protocols. When the temperature sensor detects that the system temperature exceeds the predefined threshold, the control unit automatically initiates the cooling sequence by activating the vacuum pump and cold head, eliminating the need for manual intervention and reducing downtime
3Quantity of substance
If bath-cooled systems with large volumes of liquid helium are used, then cooling capacity is sufficient, but large amounts of costly cryogenic fluid are consumed and replacement is required after quench
Solution Approach 1:
The system extracts the magnetic coil system from the liquid helium bath and places it in a vacuum environment. The cold head with cooling arm provides direct cooling to the magnetic coils without requiring large volumes of liquid helium, thereby reducing cryogenic fluid consumption while maintaining reliable cooling operation
Solution Approach 2:
The system replaces the liquid helium bath cooling mechanism with a mechanical cold head cooling system. The cold head with its cooling arm directly contacts or approaches the magnetic coils to transfer heat, substituting the chemical/thermal field of liquid helium with a mechanical refrigeration system that consumes no cryogenic fluid
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 automated and autonomous cooling of superconductive MR magnetic coil systems, reducing the need for trained personnel, shortening downtime, and making the system more compact, cost-effective, and user-friendly for final customers.
Implementation Method 1
a vacuum pump (20) disposed outside the vacuum vessel (11) and a first barrier valve (21) in a vacuum conduit (22) leading from the vacuum pump (20) into the vacuum vessel (11) are present
Implementation Method 2
a cold head (17) for cooling of the cooling arm (16) is present
Implementation Method 3
which, in the event of failure of the cold head (17), can be used to pump away liquid helium (19) in the neck tube (14) in order to cool the MR magnetic coil system (12)
Implementation Method 4
the lowermost cooling stage of the cooling arm is close to the object to be cooled; for example, close thermal coupling is established via contact of the object to be cooled and the lowermost cooling stage to a small amount of liquid helium in the cavity
Data Source
AI summary
A method for autonomously cooling down a cryogen-free superconductive magnetic coil system includes:(a1) measuring the current temperature Tactual at the magnet and comparing it to a temperature target value T1target;(a2) if Tactual>T1target, actuating a vacuum pump and opening a barrier valve in a vacuum conduit that leads from the vacuum pump into a vacuum vessel containing the magnet;(b1) measuring the current pressure Pactual in the vacuum vessel and comparing it to a pressure target value P1target;(b2) if Pactual<P1target, activating a cold head for cooling a cooling arm;(c1) measuring Tactual and comparing it to the first temperature target value T1target;(c2) if Tactual<T1target, closing the barrier valve and switching off the vacuum pump;(d1) measuring Tactual and comparing it to a second temperature target value T2target and maintaining the second temperature target value T2target.