Cryostat Getter Combination for Vacuum Maintenance
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Solution Overview
Problem
Dry magnetic resonance devices experience rapid vacuum quality deterioration due to residual gases and heat transport mechanisms, leading to extended cooling times and potential failure in achieving cryogenic temperatures during transport and storage, especially in the absence of trained service engineers.
Innovation Solution
A cryostat structure equipped with a combination of hydrogen and water getters, which are non-evaporable and non-activated, strategically placed between the outer vacuum chamber and thermal shield, effectively removing hydrogen and moisture to maintain vacuum quality and reduce heat transport, allowing for on-site re-cooling without re-establishing the vacuum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If dry magnetic resonance devices are used to reduce weight and cost, then transportation cost and weight are reduced, but vacuum quality deteriorates rapidly due to residual gases and heat transport
Solution Approach 1:
The patent applies preliminary action by pre-cooling the device to cryogenic temperatures before transportation and storage. This preliminary cooling establishes a thermal state that suppresses outgassing and heat transport during the subsequent period when the device is disconnected from the cold source, thereby maintaining vacuum quality without requiring continuous active cooling or vacuum maintenance systems.
Solution Approach 2:
The patent introduces an intermediary substance (cryogen) that mediates between the magnet structure and the external environment. This cryogen acts as a thermal sink and vacuum barrier, absorbing residual gases and preventing heat transport from the warm external environment to the cryogenic magnet structure during transportation and storage periods.
2Ease of manufacture
If dry magnetic resonance devices are used, then transportation cost is reduced, but cooling time extends significantly due to residual gases and heat transport
Solution Approach 1:
The device is pre-cooled to cryogenic temperatures before delivery to the final location. This preliminary cooling action eliminates the need for extended on-site cooling periods, as the device arrives already in the desired thermal state. The pre-cooling is performed during manufacturing or at an authorized service location, avoiding time loss during transportation and installation.
Solution Approach 2:
The cryogen serves as an intermediary thermal management medium that enables rapid cooling during manufacturing and maintains the cryogenic state during transportation. This intermediary substance allows the device to be cooled quickly in a controlled environment and then transported without requiring continuous active cooling, significantly reducing the overall time required to achieve operational temperature.
3Reliability
If vacuum pumps are used to maintain vacuum quality, then vacuum quality is improved, but device complexity and operational cost increase
Solution Approach 1:
The cryogen acts as an intermediary substance that provides passive vacuum maintenance without requiring active pumping systems. The cryogen absorbs residual gases and maintains the vacuum state through its physical properties, eliminating the need for complex vacuum pumps, control systems, and monitoring equipment while ensuring reliable vacuum quality throughout the device's operational life.
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
The combination of getters significantly reduces vacuum deterioration, enabling on-site re-cooling within 90 days or more, reducing operational costs, and allowing for less expensive and slower transportation methods, while maintaining desired vacuum quality in dry magnetic resonance devices.
Implementation Method 1
A getter (50a) consists of a mixture of a water getter and a hydrogen getter disposed freely moveable within a region (72) arranged between the outer thermal shield (43) and the outer wall of the outer vacuum chamber (42)
Implementation Method 2
The thermal shield (34) may be configured to reduce a transport of heat energy to cryogenically cooled components within the cryostat structure
Implementation Method 3
At such low temperatures, outgassing of construction materials of the cryostat is negligible and cold surfaces cryopump (i. e. retain) residual gases
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a cryostat structure (31) for a magnetic resonance device (11), comprising an outer vacuum chamber (42), a thermal shield (33,34), a main magnet (17), and a combination of getters (50), wherein the combination of getters (50) comprises a hydrogen getter and a water getter. The invention further relates to a combination of getters (50) for use in an inventive cryostat structure (31) and a magnetic resonance device (11) comprising an inventive cryostat structure (31).