Heat-Barrier Packaging With Thin Metallic Coating Insulation
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Solution Overview
Problem
Panel-like insulation elements face challenges in implementing the Dewar principle due to the need for thick walls to withstand pressure, limiting the effectiveness of vacuum insulation, and materials like polymers offer low thermal conductivity but poor gas density and radiation reflection.
Innovation Solution
A metallic coating with low emissivity and thin layer thickness is applied to a polymer carrier element, combined with a honeycomb structure and inert gas filling at subatmospheric pressure, to enhance radiation reflection and gas tightness without increasing thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a vacuum is generated in a cavity between inner and outer walls of panel-like insulation elements, then thermal insulation performance is improved, but the wall thickness must be increased to withstand external atmospheric pressure
Solution Approach 1:
The patent combines polymer material (for low thermal conductivity) with metallic coating (for gas tightness and radiation reflection) to create a composite insulation element. This composite structure achieves effective thermal insulation without requiring excessive wall thickness, as the metallic coating provides the necessary gas barrier and structural integrity at thin layers.
Solution Approach 2:
The patent changes the physical parameters of the insulation system by applying a metallic coating with specific properties (low emissivity, high gas tightness) to the polymer carrier element. This parameter change enables the system to maintain vacuum integrity and reflect thermal radiation effectively, improving insulation performance without increasing wall thickness.
2Loss of energy
If polymer materials are used as insulation elements, then low thermal conductivity is achieved, but gas density and radiation reflection capability are insufficient
Solution Approach 1:
The patent creates a composite structure by coating polymer material with a thin metallic layer. The polymer provides low thermal conductivity, while the metallic coating contributes gas tightness and high radiation reflection capability. This composite approach combines the advantages of both materials to overcome their individual limitations.
Solution Approach 2:
The patent applies different materials to different parts of the insulation element: the polymer carrier element provides bulk insulation with low thermal conductivity, while the metallic coating applied to specific surfaces provides gas tightness and radiation reflection. This local differentiation of material properties optimizes overall performance.
3Reliability
If metallic materials are used for insulation, then gas tightness and radiation reflection are improved, but thermal conductivity increases
Solution Approach 1:
The patent uses a composite structure where a thin metallic coating is applied to a polymer carrier element. The metallic coating provides gas tightness and radiation reflection, while the thick polymer layer maintains low thermal conductivity. This composite approach allows metals to be used for their beneficial surface properties without suffering from their high bulk thermal conductivity.
Solution Approach 2:
The patent employs a thin metallic film or coating on the polymer carrier element. This thin film provides the necessary gas barrier and radiation reflection properties without creating a continuous thermal conduction path, as the metal layer is sufficiently thin to minimize its thermal conductivity contribution while maintaining its barrier functions.
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 solution significantly reduces thermal conductivity and maintains low thermal energy transfer, making the insulation more effective and cost-efficient while extending the service life by using inert gases at reduced pressures.
Implementation Method 1
the thermal conductivity, the gas density and, above all, the reflection of heat rays are of great importance for the insulation properties
Implementation Method 2
The thermal conductivity, also known as the coefficient of thermal conductivity (λ), of a solid, liquid or gas is its ability to transport thermal energy in the form of heat by means of thermal conduction
Implementation Method 3
The evacuation prevents heat transport by convection
Implementation Method 4
In the context of the invention, sputtering is particularly advantageous since it enables a high layer quality even with very thin layers and allows the formation of boundary layers on polymers. Sputtering (cathode atomization) is a physical process in which atoms are released from a solid body (target) by bombardment with high-energy ions (mainly noble gas ions) and pass into the gas phase. During sputter deposition, a substrate is placed near the target so that the atoms that are ejected can condense on it and form a layer.
Data Source
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AI summary
For an insulating element (1) for bounding spaces to be thermally insulated, such as transport containers and packaging containers, comprising an in particular plate-shaped substrate element (2) made of a material having a low thermal conductivity, such as a polymer, the substrate element (2) is provided with a metallic coating (3), which has a low emissivity in order to reduce the thermal radiation, but is applied in a layer thickness of < 80 nm, preferably < 50 nm, such that the thermal conduction of the metallic coating reduces the insulating value optimized thereby only insignificantly. The metallic coating in the nanometer range does not only reduce the thermal radiation, but also enables optimal gas tightness together with minimal thermal conduction.