Graded CTE Edge Seal for Durable Vacuum Insulated Panels
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Solution Overview
Problem
Conventional vacuum insulated glass perimeter sealing systems face issues such as de-tempering of glass substrates, high manufacturing costs, and reduced durability due to thermal stress and edge seal damage.
Innovation Solution
A vacuum insulating panel design featuring a multi-layer edge seal with a main seal layer and primer layers, where the coefficient of thermal expansion (CTE) of the second seal layer is greater than that of the first seal layer, and both are optimized to reduce induced transient thermal stress and improve adhesion to glass substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-layer edge seal is used, then the manufacturing process is simple, but the seal bonding and hermiticity are insufficient
Solution Approach 1:
The edge seal is divided into multiple layers: a first seal layer in contact with the first substrate, a second seal layer with intermediate CTE, and a third seal layer in contact with the second substrate. This segmentation allows each layer to perform specific functions (adhesion, stress buffering, sealing) thereby improving overall seal reliability and hermiticity while managing thermal expansion differences between substrates.
Solution Approach 2:
The patent employs composite seal layers with different coefficients of thermal expansion (CTE) to create a gradient structure. The first seal layer has CTE matched to the first substrate, the second seal layer has intermediate CTE, and the third seal layer has CTE matched to the second substrate. This composite approach improves thermal stress distribution and adhesion while maintaining seal integrity.
2Ease of manufacture
If the CTE mismatch between seal layer and glass substrate is large, then the manufacturing is easier, but the thermal stress causes seal damage and reduced durability
Solution Approach 1:
The patent uses composite seal layers with progressively matched CTE values. The first seal layer has CTE matched to the first glass substrate, the second seal layer has intermediate CTE, and the third seal layer has CTE matched to the second glass substrate. This composite structure maintains manufacturing feasibility while ensuring thermal stress compatibility, thereby improving seal durability.
Solution Approach 2:
Different regions of the seal structure have different CTE properties tailored to their local requirements. The seal layers adjacent to each substrate have CTE matched to that substrate, while the intermediate layer has intermediate CTE. This local optimization ensures each interface is compatible with its adjacent material, preventing stress concentration and improving overall durability.
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 enhances seal bonding, hermiticity, moisture resistance, mechanical durability, and glass adhesion, while maintaining the thermal insulation properties of the vacuum insulating panel.
Implementation Method 1
wherein a coefficient of thermal expansion (CTE) of the second seal layer is greater than a CTE of the first seal layer
Implementation Method 2
The gap between the substrates may be at a pressure less than atmospheric pressure to provide insulating properties. Providing a vacuum in the space between the substrates reduces conduction and convection heat transport
Implementation Method 3
reducing radiative energy with a low-emissivity (low-E) coating provided on one of the substrates
Data Source
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AI summary
A vacuum insulating panel includes first and second substrates (e.g., glass substrates), a hermetic edge seal, a pump-out port, and spacers sandwiched between at least the two substrates. The gap between the substrates may be at a pressure less than atmospheric pressure to provide insulating properties. The vacuum insulating panel may include a multi-layer edge seal structure with coefficients of thermal expansion (CTEs) of layers of the seal structure optimized for CTE grading