Cryogenic cooling apparatus and method
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Solution Overview
Problem
Cryogen-free cryogenic systems face challenges in efficiently and automatically loading samples without warming the entire system, particularly due to the absence of liquid cryogens for pre-cooling and the need for manual thermal couplings, which can cause heat shock and damage to delicate components like dilution refrigerators.
Innovation Solution
A method involving the removal of operational fluid from the dilution refrigerator, pre-cooling the target apparatus within the system using a mechanical refrigerator, and then re-introducing the fluid to cool the apparatus to ultra-low temperatures, allowing for 'warm' sample loading without bringing the system to atmospheric conditions and reducing manual intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a warm sample is loaded directly into a cold cryostat in cryogen-free systems, then sample change time is reduced, but thermal shock damages delicate components like dilution refrigerators
Solution Approach 1:
The patent applies preliminary action by pre-cooling the sample in a sample chamber before it is transferred to the cold stage. The sample is cooled from room temperature to a lower temperature using a sample cooling mechanism (such as a Peltier device or cold finger) before insertion into the dilution refrigerator. This preliminary cooling reduces the thermal shock to the delicate dilution refrigerator components when the warm sample is introduced, while still enabling relatively rapid sample changes without warming the entire system.
2Object-affected harmful factors
If liquid cryogens are used to pre-cool the sample, then thermal shock is reduced, but the system becomes more complex and requires liquid cryogen handling infrastructure
Solution Approach 1:
The patent extracts the cryogen handling function from the main cryostat system by implementing a separate sample pre-cooling mechanism. Instead of using liquid cryogens to cool the entire system or requiring complex cryogen delivery infrastructure, the invention uses a dedicated sample cooling device (such as a Peltier cooler or cold finger connected to the cold stage) that pre-cools only the sample before insertion. This eliminates the need for liquid cryogen storage, handling, and safety infrastructure while still providing thermal shock protection.
Solution Approach 2:
The patent replaces the mechanical/chemical system of liquid cryogen cooling with an electrical or solid-state cooling mechanism. The sample cooling is achieved through electrical Peltier devices or thermal conduction from the cold stage, eliminating the need for liquid cryogen circulation systems, pumps, and associated mechanical infrastructure. This substitution reduces system complexity while maintaining the thermal shock protection function.
3Ease of operation
If the entire system is warmed up for sample changes, then sample loading is simplified, but cooling time increases significantly
Solution Approach 1:
The patent segments the cooling function into two distinct zones: the sample chamber and the cold stage/dilution refrigerator. The sample is cooled separately in the sample chamber using a dedicated cooling mechanism before transfer, while the main cold stage and dilution refrigerator remain at their operational low temperatures. This segmentation allows sample preparation and cooling to occur independently without requiring the entire system to be warmed up, maintaining both operational simplicity and energy efficiency.
4Manufacturing precision
If manual thermal couplings are required for staged pre-cooling, then cooling control is precise, but extensive manual intervention is needed
Solution Approach 1:
The patent implements self-service by designing an automated sample transfer mechanism that performs the thermal coupling and sample transfer operations without manual intervention. The sample is automatically transferred from the sample chamber to the cold stage using a robotic arm, pneumatic actuator, or motorized positioning system. The thermal coupling is established automatically through designed mechanical interfaces (such as spring-loaded contacts or thermally conductive fixtures) that engage when the sample reaches its final position, eliminating the need for manual thermal coupling operations while maintaining precise cooling control.
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 method enables efficient, automated sample loading and unloading with reduced heat load and risk of damage, maintaining comparable times to traditional methods while enhancing automation and minimizing thermal shock.
Implementation Method 1
pre-cooling the target apparatus in the target region to a first temperature using a mechanical refrigerator
Implementation Method 2
mechanical refrigerator
Implementation Method 3
operating the dilution refrigerator using the operational fluid so as to cool the target apparatus in the target location to a second temperature that is lower than the first temperature
Implementation Method 4
cool the target apparatus in the target location to a second temperature
Implementation Method 5
providing the operational fluid to the dilution refrigerator
Implementation Method 6
cool the target apparatus in the target location to a second temperature
Data Source
AI summary
A method is provided of operating a cryogenic cooling system, in which a target region for receiving a sample is cooled by a dilution refrigerator containing an operational fluid. Firstly any operational fluid is removed from the dilution refrigerator. Target apparatus comprising the sample is loaded from a high temperature location to the target region. The target apparatus is then pre-cooled in the target region to a first temperature using a mechanical refrigerator. The operational fluid is then supplied to the dilution refrigerator and the dilution refrigerator operated so as to cool the target apparatus in the target location to a second temperature that is lower than the first temperature. A suitable system for performing the method is also disclosed.