Dry Ice Packaging With Dual-Permeability Insulation Panels

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Solution Overview

Problem

Insulated shipping containers fail to maintain low temperatures effectively due to the rapid escape of carbon dioxide gas after dry ice sublimation, leading to reduced cooling duration.

Innovation Solution

The use of a casing with an impermeable outer sheet and a permeable inner sheet, where dry ice is placed within the container, allowing carbon dioxide gas to permeate through the inner sheet and become trapped, slowing its escape and maintaining low temperatures longer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If an impermeable casing is used to retain carbon dioxide gas, then cooling duration is extended, but carbon dioxide gas cannot permeate through the casing

Engineering Contradiction:

Improvecooling durationVSAvoidcarbon dioxide gas retention

Core Design Contradiction:

Duration of action of stationary objectVSLoss of substance

Solution Approach 1:

The casing is divided into two distinct layers: an inner permeable layer that allows carbon dioxide gas to pass through, and an outer impermeable layer that prevents gas escape. This segmentation enables the system to both retain and allow permeation of carbon dioxide gas simultaneously, resolving the contradiction between extending cooling duration and preventing gas loss.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The casing employs a composite structure combining materials with different gas permeability properties. The inner layer uses a permeable material (such as polyethylene) that allows carbon dioxide gas to pass through, while the outer layer uses an impermeable material (such as polypropylene or aluminum foil) that prevents gas escape. This composite material approach enables both gas retention and controlled permeation.

Inventive Principle:

Principle #40Composite materials

2Temperature

If dry ice is placed in a sealed container, then refrigeration is maintained, but carbon dioxide gas builds up pressure and may cause safety issues

Engineering Contradiction:

Improverefrigeration temperatureVSAvoidcarbon dioxide gas pressure

Core Design Contradiction:

TemperatureVSStress or pressure

Solution Approach 1:

The permeable inner layer acts as an intermediary between the dry ice sublimation process and the container interior. It allows carbon dioxide gas to pass through in a controlled manner, preventing pressure buildup while still enabling the refrigeration function. This intermediary layer resolves the contradiction between maintaining low temperature and preventing excessive pressure.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Stress or pressure

If carbon dioxide gas is allowed to escape freely from the container, then pressure is relieved, but cooling duration is reduced

Engineering Contradiction:

Improveinternal pressureVSAvoidcooling duration

Core Design Contradiction:

Stress or pressureVSDuration of action of stationary object

Solution Approach 1:

The casing exhibits different gas permeability qualities at different locations/layers: the inner layer is locally permeable to allow pressure relief, while the outer layer is locally impermeable to prevent gas escape. This spatial differentiation of material properties enables simultaneous pressure management and cooling duration extension.

Inventive Principle:

Principle #3Local quality

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 configuration extends the duration of cooling by retaining carbon dioxide gas within the container, ensuring longer-lasting refrigeration of contents during shipping or storage.

Implementation Method 1

an inner sheet which is permeable to carbon dioxide gas... some portion of gaseous carbon dioxide passes through the permeable sheet of the casing

Methodology Applied

Scientific EffectPermeation: Permeation

Implementation Method 2

an outer sheet which is impermeable to carbon dioxide gas... retained and slowed in its eventual escape from the container

Methodology Applied

Scientific EffectPhysical containment: Physical Containment

Implementation Method 3

upon sublimation of the dry ice, some portion of gaseous carbon dioxide passes through the permeable sheet

Methodology Applied

Scientific EffectSublimation: Sublimation

Data Source

PatentUS11820579B1Insulated packaging for use with dry ice

Publication Date: 2023.11.21 LANTZ GARY W

AI summary

A shipping container with an enclosure of insulating panels which swell in response to sublimation of a carbon dioxide mass within the enclosure. The insulating panels are made of a casing with an outer sheet which is impermeable to carbon dioxide gas and an inner sheet which is permeable to carbon dioxide gas. Dry ice is placed within the shipping container, along with contents which require refrigeration, and the container is closed (sealed or somewhat sealed). After closure, and upon sublimation of the dry ice, some portion of gaseous carbon dioxide passes through the permeable sheet of the casing and some may leak from the container. Because some portion of the sublimated gas enters the casing, it is retained and slowed in eventual escape from the container, thereby maintaining low temperatures within the container longer than a system with an impermeable casing.