Methods for pre-charging carbon dioxide snow

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Solution Overview

Problem

Existing methods for preserving biological samples during clinical trials face challenges such as labor-intensive dry ice handling, temperature gradients, logistical complexities, and high costs associated with cryogenic liquid nitrogen-based systems, leading to potential sample degradation and increased costs.

Innovation Solution

A method for pre-charging CO2 snow into insulated containers at a first location, which involves generating CO2 snow within the container using a CO2 snow charger, and then transporting the pre-charged container to a second location for loading perishable items, allowing for automated and efficient temperature maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual dry ice loading is used in insulated boxes, then sample preservation is achieved, but labor intensity and operational complexity increase

Engineering Contradiction:
Improvesample preservationVSAvoidlabor intensity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system uses CO2 cylinders that automatically generate dry ice through pressure-driven phase change, eliminating the need for manual dry ice handling. The container self-regulates temperature through the sublimation process, reducing operational complexity while maintaining sample preservation reliability

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces manual mechanical dry ice loading with an automated CO2 generation system using pressure-regulated cylinders and phase change mechanisms, significantly reducing labor intensity while maintaining the cooling function

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Temperature

If conventional insulated boxes with dry ice are used, then cooling is provided, but temperature gradients develop during transport

Engineering Contradiction:
Improvecooling capabilityVSAvoidtemperature uniformity
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The CO2 cooling system is divided into multiple cylinders distributed throughout the container, with each cylinder serving a specific zone. This segmentation ensures uniform cold distribution and prevents temperature gradients while maintaining overall cooling capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different CO2 cylinders are positioned at specific locations within the container to provide localized cooling where needed, ensuring temperature uniformity across the entire sample storage space rather than relying on a single centralized cooling source

Inventive Principle:
Principle #3Local quality

3Temperature

If liquid nitrogen-based vapor vessels are used, then cryogenic temperature maintenance is achieved, but cost and preparation time increase

Engineering Contradiction:
Improvecryogenic temperature maintenanceVSAvoidpreparation complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The system uses CO2 instead of liquid nitrogen, changing the cryogenic agent to one that operates at higher temperatures and does not require complex absorption/desorption cycles. This simplifies the system while maintaining effective cryogenic cooling for sample preservation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent extracts the complex preparation steps (pouring, absorbing, decanting) from the cooling system by using pre-filled CO2 cylinders that require no preparation, eliminating device complexity while maintaining cryogenic temperature capability

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If expedited delivery methods are used for insulated boxes, then sample quality is maintained, but logistical complexity and cost increase

Engineering Contradiction:
Improvesample qualityVSAvoidlogistical complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The CO2 cylinders are pre-filled and sealed at the manufacturing site, with dry ice generation occurring automatically upon activation. This preliminary preparation eliminates the need for complex shipping logistics and expedited delivery, as the system is self-sufficient from activation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system maintains sample quality through self-regulating CO2 generation and sublimation processes that automatically adjust to transport conditions, eliminating dependence on expedited delivery and reducing logistical complexity

Inventive Principle:
Principle #25Self-service

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 provides a cost-effective and efficient means of preserving samples by maintaining consistent temperatures during transport, reducing labor and logistical complexities, and minimizing sample degradation, while eliminating the need for on-site dry ice inventory.

Implementation Method 1

generating the CO2 snow within the empty or the partially empty container

Methodology Applied
Scientific EffectPhase change (liquid to solid): Phase Change

Implementation Method 2

generating the CO2 snow within the empty or the partially empty container to create the pre-charged container

Methodology Applied
Scientific EffectJoule-Thomson effect: Joule-Thomson Effect

Implementation Method 3

The dry ice cools the interior of the insulated box as it sublimates to carbon dioxide vapor

Methodology Applied
Scientific EffectSublimation: Sublimation

Implementation Method 4

preserving samples by maintaining consistent temperatures during transport

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3728966B1Methods for pre-charging carbon dioxide snow
Publication Date: 2026.04.01 PRAXAIR TECH INC
  • EP3728966B1 patent drawingFigure 1a~1b
  • EP3728966B1 patent drawingFigure 2a
  • EP3728966B1 patent drawingFigure 2b~4

AI summary

Manual and automated methods of pre-charging an empty or partially empty insulated container with C02 snow are provided. A first location such as a charging location charges C02 liquid into a container to create a pre-charged container with C02 snow. The charging location prepares the pre-charged container for delivery to a second location, either by itself, or through a third party. The second location may be a clinical site, which upon receipt of the pre-charged container, loads a perishable item such as a biological sample into the pre-charged container. A user receives the pre-charged container with perishable item and removes the perishable item from the pre-charger container for testing (e.g., biological testing). Depending on the level of depletion of the C02 snow in the pre-charged container, the user returns the depleted container to the first location or the intermediate location.