Sealed MRI Magnet Cooldown Loop for Faster Cryostat Startup
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High field MRI magnets with sealed cryostats face prolonged cooldown times due to the need to cool a large helium inventory, which is costly and time-consuming, and existing cryogen-free designs aim to mitigate this but still require extended periods to reach cryogenic temperatures.
Innovation Solution
A cooldown acceleration loop is integrated within the sealed cryostat, allowing for the flow of cryogenic fluids through external ports to expedite the cooling process, combined with getter material to enhance vacuum maintenance and reduce thermal conductivity, thereby accelerating the cooldown of superconducting magnets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a hermetically sealed cryostat with large helium inventory is used, then the magnet can maintain cryogenic temperature for extended periods, but the cooldown time becomes excessively long
Solution Approach 1:
The cooling system is segmented into two distinct parts: a sealed internal cooling system containing the helium inventory for long-term operation, and an external cooldown acceleration loop that can be temporarily connected to rapidly remove heat during the cooldown phase. This segmentation allows each subsystem to be optimized for its specific function without compromise.
Solution Approach 2:
The external cooldown acceleration loop is prepared and connected before the cooldown process begins, allowing the system to immediately start rapid cooling. The loop is pre-filled with cryogenic fluid and thermally coupled to the sealed cooling system, enabling preliminary heat extraction before the sealed system would otherwise require lengthy passive cooling.
2Ease of operation
If a hermetically sealed cooling system is used to eliminate helium resupply, then maintenance complexity is reduced, but cooldown acceleration becomes difficult
Solution Approach 1:
The system transitions from a static sealed configuration to a dynamic state during cooldown, where the external loop is connected to accelerate cooling. After cooldown completion, the system returns to its static sealed state for long-term operation. This dynamic adaptability allows the system to optimize for both rapid cooldown and simple long-term maintenance.
Solution Approach 2:
The external cooldown acceleration loop acts as an intermediary system that temporarily interfaces with the sealed cooling system during the cooldown phase. This intermediary provides the necessary heat extraction capability without requiring permanent modification to the sealed system, thus maintaining both cooldown speed and maintenance simplicity.
3Device complexity
If conventional cooling methods are used, then system complexity is minimized, but production and installation time are extended
Solution Approach 1:
The cooling functionality is segmented between the simple sealed internal system and the external acceleration loop. This segmentation allows the core magnet design to remain relatively simple while the external loop provides the productivity boost during installation and commissioning phases.
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 approach significantly reduces the production, installation, and startup times of MRI systems by accelerating the cooldown process, minimizing the thermal load on the coldhead, and allowing on-site maintenance without mechanical pumping.
Implementation Method 1
a second cooling system having a first portion in contact with the sealed cooling system within the cryostat
Implementation Method 2
flowing a cryogenic fluid through the cooldown acceleration loop
Implementation Method 3
a vacuum vessel; one or more superconducting coils disposed within the vacuum vessel
Implementation Method 4
suspended through low-thermal conductivity straps in a high vacuum to minimize the amount of conductive and convective heat reaching the coils
Implementation Method 5
Getter material, such as charcoal or any other suitable getter material, may be used to achieve this level of vacuum. As soon as the temperature drops below a certain value, it becomes active and traps the gas molecules that reach it
Data Source
AI summary
An apparatus (200) includes: a cryostat (214) containing a volume of cryogenic fluid; one or more superconducting coils (202) within the cryostat; a sealed cooling system (204) within the cryostat and configured to maintain the one or more superconducting coils n a persistent state; and a second cooling system (210) having a first portion in contact with the sealed cooling system within the cryostat, a second portion extending outside of the cryostat.