Shipping container
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Solution Overview
Problem
Current shipping containers for cryopreserved samples face challenges in maintaining low temperatures over extended periods without conventional cryogenic materials, and existing solutions like dry shippers with porous materials are prone to contamination and have design limitations that make them unsuitable for sterile environments.
Innovation Solution
A shipping container equipped with a gravitational thermosyphon thermal diode and a Stirling cryocooler, which allows for temperature maintenance without cryocoolants, combined with a Dewar vessel and vacuum insulated panels for enhanced thermal performance and resistance to failure, along with sensors and communication units for remote monitoring and controlled rate freezing/thawing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cryogenic materials like liquid nitrogen are used for cooling, then low temperature is achieved, but safety risks arise due to potential spillage
Solution Approach 1:
The invention extracts the harmful liquid nitrogen from the system and replaces it with a solid carbon dioxide cooling system that does not pose spillage risks. The phase change material is contained in a separate chamber, eliminating the safety hazard while maintaining cryogenic cooling capability.
Solution Approach 2:
The invention changes the physical state parameter of the cooling agent from liquid (nitrogen) to solid (carbon dioxide), and changes the phase transition from liquid-gas to solid-gas sublimation. This parameter change eliminates the spillage hazard while achieving comparable cooling temperatures.
2Object-affected harmful factors
If porous materials like molecular sieves are used to absorb liquid nitrogen, then liquid nitrogen spillage is prevented, but the materials are easily contaminated and require sterilisation
Solution Approach 1:
The invention removes the porous absorption materials (molecular sieves, zeolites) from the system and replaces them with a contained solid carbon dioxide phase change system. This eliminates the contamination and sterilisation issues associated with porous materials while maintaining safety.
Solution Approach 2:
The invention employs a disposable or easily replaceable solid carbon dioxide cartridge system that does not require sterilisation. The phase change material is sealed in a container that can be replaced without cleaning or sterilisation procedures, simplifying the operation significantly.
3Strength
If Dewar vessels are made cylindrical or spherical to ensure equal pressure distribution, then structural strength is improved, but the aperture is narrow and charging is difficult
Solution Approach 1:
The invention segments the cooling system into a separate rechargeable cartridge containing the solid carbon dioxide phase change material. This allows the main Dewar vessel to maintain its optimal cylindrical shape for strength, while the segmented cartridge can be easily inserted and removed through a smaller aperture.
Solution Approach 2:
The invention nests the rechargeable phase change material cartridge inside the main Dewar vessel. The cartridge is designed to fit within the available space and can be inserted through the aperture, combining the structural benefits of the cylindrical Dewar with the operational ease of a removable inner component.
4Ease of operation
If solid carbon dioxide is used as cooling material, then safety and ease of operation are improved, but the temperature of -78.5°C is not low enough for prolonged cryopreservation
Solution Approach 1:
The invention uses preliminary active cooling (such as liquid nitrogen or mechanical refrigeration) to pre-cool the solid carbon dioxide phase change material below its sublimation point. This preliminary action lowers the temperature of the CO2 to -100°C or lower, enabling it to provide adequate cryopreservation temperatures for prolonged storage.
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 solution enables the maintenance of cryopreserved samples at cryopreservation temperatures for extended periods, ensures sample integrity, and allows for remote monitoring and controlled temperature management, making it suitable for use in sterile environments and locations without access to conventional cryogenic storage facilities.
Implementation Method 1
The shipping container comprises a thermal diode operable in a first state to provide cooling to the cavity and in a second state to impair heat transfer into the cavity. The thermal diode is a gravitational thermal diode
Implementation Method 2
The thermal diode is a gravitational thermal diode, i.e. a diode that operates under the influence of gravity
Implementation Method 3
The shipping container comprises an insulated housing, the housing defining a cavity
Implementation Method 4
The cavity is adapted to receive a replaceable cartridge of cryogenic phase transition material
Data Source
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AI summary
The present invention relates to a shipping container for cryopreserved biological samples in which a cryopreserved sample can be maintained on arrival at its destination for a period of time, for example several months.