Apparatus and method for introduction of a material into a cryogenic system
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Solution Overview
Problem
Current cryogenic cooling systems face limitations in cooling capacity and efficiency due to the limited volume of liquid helium, which restricts the number of samples that can be cooled and polarized, and the mechanical components within the cryogenic environment can compromise the robustness of the device.
Innovation Solution
An apparatus and method that directs heat from the introduced material away from the liquid helium bath to a cooling unit using an airlock chamber, equilibrator, and a cooling unit thermally coupled to the equilibrator, allowing for conductive and convective cooling of samples, thereby minimizing the impact on the helium bath's temperature and extending the operational period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If warm samples are introduced into the liquid helium bath for cooling, then the samples can be cooled to cryogenic temperatures, but the temperature of the helium bath increases and liquid helium vaporizes, reducing the operational duration
Solution Approach 1:
The cooling process is segmented into multiple stages: pre-cooling the sample in the airlock chamber before introduction to the helium bath, then progressive cooling through controlled thermal contact. This segmentation reduces the thermal shock to the helium bath, minimizing vaporization and extending operational duration while still achieving the required cryogenic temperatures for the sample.
2Productivity
If the volume of liquid helium is increased to cool more samples, then the processing capacity increases, but the system size and cost increase
Solution Approach 1:
Samples are pre-cooled in the airlock chamber using a separate cooling mechanism before being introduced to the liquid helium bath. This preliminary cooling action reduces the thermal load on the helium bath, allowing the same volume of helium to process more samples over time, thereby increasing productivity without increasing helium volume.
3Temperature
If mechanical pumps are used to reduce pressure above the helium bath, then the temperature can be reduced, but helium is expelled into the ambient environment, making it difficult and expensive to reuse
Solution Approach 1:
A sorption pump using charcoal-based sorbent is introduced as an intermediary mechanism to reduce pressure above the helium bath without expelling helium. The charcoal absorbs gaseous helium at low temperatures, creating the necessary vacuum conditions for cryogenic operation while allowing the helium to be desorbed and reused, eliminating loss of the cryogen.
4Quantity of substance
If the mass of charcoal in the sorption pump is increased to generate more liquid helium, then the cooling capacity increases, but the physical size of the container increases
Solution Approach 1:
The sorption pump is designed with optimized local properties of the charcoal sorbent, using materials with high sorption capacity per unit mass. This allows achieving the required liquid helium generation capacity with a compact charcoal mass, maintaining a small container volume while still producing sufficient cryogen for multiple sample processing cycles.
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 efficient cooling of multiple samples to temperatures below 1 Kelvin with minimal impact on the helium bath's temperature, increasing the processing capacity and reducing the need for frequent cryogen transfers, while maintaining the robustness of the device.
Implementation Method 1
a cooling unit thermally coupled to the equilibrator
Implementation Method 2
convecting heat from the sample while iteratively lowering the sample into the cryogenic helium bath
Data Source
AI summary
Provided is an apparatus and method comprising, an airlock chamber; a cryogenic chamber; an equilibrator positioned between the airlock chamber and the cryogenic chamber that is configured to allow for the passage of a sample along to the cryogenic chamber; and a cooling unit that is thermally coupled to the equilibrator. Collectively, the airlock chamber, equilibrator, and the cryogenic chamber define a travel path. A machine-readable medium, comprising instructions which when executed by a controller causes a sample to be cooled, is also provided.