Cryostat Gas-Coupled Cooling for Low-Vibration Temperature Control
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Solution Overview
Problem
Current cryogenic measurement systems face challenges in efficiently regulating temperature in cryostats, particularly in delivering variable cooling power to superconducting magnets and sample chambers, while minimizing coolant usage and reducing system complexity and vibration transfer.
Innovation Solution
The system employs a multistage helium-temperature cryogenic cooler with solid conduction contacts and a thermosiphon effect, eliminating the need for physical links and mechanical valves, allowing for simultaneous temperature sweeping and high thermal conductance between the cooler and cryostat components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If physical links or fixed heat exchangers are used to couple the cryogenic cooler to the cryostat assembly, then thermal coupling is achieved, but system complexity and maintenance difficulty increase
Solution Approach 1:
The patent removes physical links and fixed heat exchangers from the system, replacing them with a gas-based thermal coupling mechanism. The cryogenic cooler operates independently without mechanical connections to the cryostat assembly, eliminating the complexity and maintenance issues associated with physical couplings while maintaining effective thermal transfer through the working gas.
Solution Approach 2:
The patent introduces a gas intermediary (helium or nitrogen) to transfer thermal energy between the cryogenic cooler and the cryostat assembly. This gas-mediated heat transfer eliminates the need for direct physical contact, reducing mechanical complexity while maintaining thermal coupling efficiency.
2Loss of energy
If physical links are used to couple the cryogenic cooler to the cryostat, then thermal transfer is enabled, but vibration energy is transferred to the sample area
Solution Approach 1:
The patent uses a gas intermediary to transfer thermal energy without mechanical contact. This eliminates the vibration transfer pathway that exists in physical link systems, as the gas coupling does not transmit mechanical vibrations from the cooler to the sample area while maintaining effective heat transfer.
Solution Approach 2:
The patent removes physical links that serve as vibration transmission pathways. By eliminating mechanical connections between the cooler and cryostat assembly, the system prevents vibration energy from reaching the sample area while maintaining thermal transfer through gas-phase heat exchange.
3Reliability
If flexible braided metal links are used to physically couple the PTC to the cryostat, then thermal coupling is achieved, but modularity and system flexibility are limited
Solution Approach 1:
The patent removes flexible braided metal links and other physical coupling mechanisms, enabling the cryogenic cooler to operate as a modular, independently positionable unit. The gas-based thermal coupling allows the cooler to be moved and repositioned without constraint, enhancing system modularity and flexibility for different experimental configurations.
Solution Approach 2:
The patent employs gas-phase thermal coupling (pneumatic principle) instead of mechanical links. This allows the cryogenic cooler to be freely positioned and repositioned within the cryostat assembly, providing modularity and adaptability for various experimental setups without being constrained by physical linkages.
4Power
If additional thermal couplings are added to increase heat exchange rate, then cooling power is improved, but system complexity and maintenance requirements increase
Solution Approach 1:
The patent removes the need for additional thermal couplings and heat exchangers by using a gas-based thermal transfer system. The working gas circulates freely between the cooler and cryostat components, providing efficient heat exchange without requiring complex additional coupling mechanisms, thus maintaining high cooling power with reduced system complexity.
Solution Approach 2:
The patent uses gas-phase convection and conduction to transfer heat efficiently throughout the cryostat assembly. This pneumatic thermal coupling system provides distributed heat exchange throughout the volume, eliminating the need for multiple discrete thermal couplings while maintaining high cooling power and simple system architecture.
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 enables rapid initial cool-down, extended operation with minimal helium replenishment, reduced maintenance, and improved thermal conductance, while minimizing vibrations and system complexity, allowing for precise temperature control across a wide range.
Implementation Method 1
a thermally conductive element in thermal contact with the magnet assembly and in contact with gaseous or liquid helium that is condensed by the cryogenic cooler
Implementation Method 2
employs the process of evaporation of a continuous stream of liquid helium
Implementation Method 3
The liquid helium level in the cryogenic cooler is controlled by adjusting the liquid helium flow rate through the thermosiphon
Data Source
AI summary
A cryostat for providing temperature regulation, one purpose being measuring physical properties of materials, the cryostat employing a superconducting magnet assembly for generating variable magnetic field in the sample space and a cryogenic cooler for cooling the sample space. The cryogenic cooler chamber configuration provides for efficient heat exchange between different stages of the cryogenic cooler without the need for physical heat links. This construction enables selective delivery of cooling power from the cryogenic cooler to the desired areas within the cryostat without using flexible physical thermal links. A counter flow exchanger and ambient temperature valves facilitate efficient use of the cryogenic cooler stages. The removal of large heat load generated by the superconducting magnet while operating in the sweeping mode is achieved, in part, by employing a solid plate thermal coupling element between the cryogenic cooler chamber and the magnet assembly.