Double Bag Vacuum Insulation Panel Steam Molding
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Solution Overview
Problem
Vacuum insulation panels (VIPs) experience a significant drop in R-value due to exposure to high temperatures and moisture during steam chest molding, leading to reduced thermal insulation effectiveness.
Innovation Solution
A double bag VIP design is implemented, where a porous core is encapsulated in a heat sealable inner envelope and further protected by an outer gas-impermeable bag made of materials like nylon or PET, providing additional thickness and barrier resistance to maintain high insulation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional single bag VIP is used during steam chest molding, then the manufacturing process can be completed, but the R-value drops significantly due to high temperature and moisture exposure
Solution Approach 1:
The patent applies nesting by placing the first bag containing the porous core inside a second outer bag, creating a nested double-bag structure. This allows the VIP to withstand steam chest molding temperatures while the inner bag maintains the vacuum seal and the outer bag provides thermal and moisture barrier protection, thereby maintaining R-value stability during manufacturing
Solution Approach 2:
The patent uses composite material structure by combining different bag materials - the first bag made from heat sealable material suitable for vacuum sealing, and the second outer bag made from temperature-resistant material that can withstand steam chest molding conditions. This composite approach allows the VIP to achieve both manufacturability through steam molding and reliability in maintaining insulation performance
2Temperature
If the plastic film thickness is increased to withstand high temperatures, then temperature resistance improves, but the flexibility and ease of vacuum sealing deteriorate
Solution Approach 1:
The patent segments the protective function into two separate bags with different material properties and thicknesses. The first inner bag uses thinner heat sealable material optimized for vacuum sealing, while the second outer bag uses thicker temperature-resistant material for thermal protection. This segmentation allows each layer to be optimized for its specific function without compromising the other
Solution Approach 2:
By nesting the heat sealable first bag inside the temperature-resistant second bag, the patent allows the thinner inner bag to maintain flexibility and ease of vacuum sealing, while the thicker outer bag provides the necessary temperature resistance. The nested structure enables both thin material properties and thick material protection to coexist
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 double bag VIP maintains an R-value of at least 28 hr-ft2-° F./BTU-in with less than a 10% drop after exposure to temperatures up to 95°C for 7 seconds, significantly improving thermal insulation stability compared to conventional VIPs.
Implementation Method 1
A vacuum insulation panel is a product composed of a rigid, highly-porous nano size material core enclosed within a metalized or non-metalized plastic bag. The vacuum reduces the pressure inside the bag to within the range of 30 millibars to 1 millibar.
Implementation Method 2
The vacuum reduces the pressure inside the bag to within the range of 30 millibars to 1 millibar. The vacuum (lack of air molecules) is an excellent insulator where conduction, convection and radiation sources are eliminated.
Implementation Method 3
The inner envelope is made from a substantially gas impermeable first material and is heat sealable, allowing it to be sealed to enclose the porous core.
Data Source
AI summary
A double bag vacuum insulation panel is provided. The double bag VIP comprises a porous core, a heat sealable inner envelope and an outer bag. The inner envelope is made from a substantially gas impermeable first material having a first thickness and defines an interior having a pressure of less than or equal to about 30 millibar. The outer bag is made from a substantially gas impermeable second material having a second thickness. The outer bag encapsulates the inner envelope.