Cryogenic systems
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Solution Overview
Problem
Current systems for maintaining samples at ultra-low temperatures face challenges in preventing temperature spikes and fluctuations, which can lead to sample degradation, especially during transfer or storage operations that require exposure to higher temperatures for manipulation, sorting, or shipping.
Innovation Solution
A cryogenic processing system with a container featuring a gas-permeable dry-ice retainer that divides the chamber into a sample-holding portion and a dry ice retention space, allowing CO2 gas to pass through while keeping dry ice separate, maintaining temperatures below -50°C for extended periods without additional dry ice, even with the chamber opening constantly accessible.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If samples are stored in conventional frozen storage systems, then sample integrity is maintained at low temperature, but samples require exposure to higher temperatures for manipulation which causes temperature spikes and degradation
Solution Approach 1:
The chamber is segmented into two distinct zones: a sample-holding portion and a dry ice retention space separated by a gas permeable retainer. This allows samples to be manipulated in the sample-holding portion while dry ice remains confined to the retention space, enabling operation ease without compromising sample integrity through temperature spikes.
Solution Approach 2:
A gas permeable retainer serves as an intermediary barrier between the dry ice retention space and the sample-holding portion. It allows CO2 gas to pass through for cooling while preventing direct contact between dry ice and samples, thus maintaining sample integrity during manipulation operations.
2Ease of operation
If the chamber opening is kept constantly open for user access, then manipulation accessibility is improved, but temperature stability deteriorates
Solution Approach 1:
The dry ice retention space continuously generates cold CO2 gas that automatically circulates through the gas permeable retainer into the sample-holding portion. This self-regulating cooling system maintains temperature stability even when the chamber opening is constantly open for user access, as the cooling effect is continuously replenished without requiring chamber closure.
3Temperature
If dry ice is placed directly in the sample-holding portion, then cooling effectiveness is improved, but sample contamination and direct contact damage occur
Solution Approach 1:
The gas permeable retainer acts as an intermediary that allows CO2 gas to pass through for effective cooling while blocking direct contact between dry ice and samples. This resolves the contradiction by enabling cooling effectiveness through gas permeability while preventing sample damage through physical separation.
Solution Approach 2:
The retainer is made of gas permeable material with pores small enough to retain dry ice pieces while allowing CO2 gas molecules to pass through. This porous structure enables effective cooling gas flow while preventing direct contact between dry ice and samples, eliminating sample damage from direct contact.
4Temperature
If additional dry ice is frequently added to maintain temperature, then temperature stability is improved, but operational complexity and time consumption increase
Solution Approach 1:
The dry ice retention space is designed to hold a sufficient quantity of dry ice in advance. The confined retention space efficiently stores dry ice that will be consumed over time, allowing the system to maintain temperature stability for extended periods without requiring frequent replenishment, thus reducing operational time and complexity.
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 system effectively maintains samples at ultra-low temperatures, preventing degradation by ensuring a stable cold environment during handling and transport, allowing for continuous access and extended manipulation without compromising sample integrity.
Implementation Method 1
at least one gas permeable dry-ice retainer vertically disposed within the chamber and positioned to permit direct access to the chamber floor through the chamber opening
Implementation Method 2
a container comprising an insulated chamber
Implementation Method 3
the total volume of the dry ice retention space(s) is less than the volume of the sample-holding portion
Data Source
AI summary
Cryogenic devices are provided in which solid carbon dioxide (dry ice) is used to maintain a temperature zone in which samples can be manipulated under conditions in which the sample is maintained at a temperature below −50 C.