Vacuum Insulation Body with Foam Passages for Fast Evacuation
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Solution Overview
Problem
Vacuum insulation spaces in complex-shaped insulation boxes, such as refrigerators, face challenges in efficiently evacuating gas due to high evacuation resistance from open-cell urethane foam, leading to prolonged vacuum-evacuation times, which hinders commercialization.
Innovation Solution
Incorporating through passages, such as through holes or grooves, in the open-cell urethane foam to facilitate direct evacuation of gas through a vacuum outlet, significantly reducing the vacuum-evacuation time by improving gas evacuation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If open-cell urethane foam is used to fill the insulation space, then the insulation space can be vacuum-evacuated, but the evacuation resistance is high causing the vacuum-evacuation time to be several hours to several days
Solution Approach 1:
The patent utilizes open-cell urethane foam with a porous structure that allows gas permeability between adjacent cells. The foam's cellular structure with interconnected pores enables vacuum evacuation while maintaining insulation performance. The porosity of the material is key to resolving the contradiction between achieving vacuum and maintaining reasonable evacuation time.
Solution Approach 2:
The patent optimizes the density and cell structure parameters of the open-cell urethane foam to balance evacuation resistance and insulation performance. By controlling the foam's physical parameters such as cell size, wall thickness, and overall density, the patent achieves a state where vacuum evacuation is possible within acceptable timeframes while maintaining effective thermal insulation.
2Strength
If the resin content in the open-cell urethane foam is high, then the structural strength is improved, but the through-hole formation becomes difficult reducing air permeability between cells
Solution Approach 1:
The patent carefully controls the resin content and foam density parameters to achieve an optimal balance. By adjusting these physical parameters, the patent ensures sufficient structural strength while maintaining adequate porosity and air permeability for vacuum evacuation. The specific parameter ranges are optimized to prevent excessive evacuation resistance.
Solution Approach 2:
The patent may employ different foam densities or structures in different regions of the insulation space. The skin layer near boundaries might have different properties than the core layer, allowing localized optimization of both strength and permeability characteristics to resolve the contradiction between structural requirements and evacuation efficiency.
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 introduction of through passages in the open-cell urethane foam allows for rapid evacuation of the insulation space, reducing the time required to achieve a high vacuum level from several hours to minutes, making the process more viable for commercial applications.
Implementation Method 1
The open-cell urethane foam is to have air permeability between adjacent cells both in cell film portions (membranous portions between the cells) of the urethane foam and in cell framework portions
Implementation Method 2
the insulation box is vacuum-evacuated by a vacuum-evacuator connected to the outlet of the box
Implementation Method 3
Vacuum insulation materials have about 20 times better insulation performance than rigid urethane foam, and their insulation performance can be maintained even if the materials are smaller in thickness
Data Source
AI summary
A vacuum insulation body includes an outer box (2), an inner box (3), open-cell urethane foam (4) in the insulation space (1b) between the outer box (2) and the inner box (3); and a vacuum outlet (6) in one of the outer box (2) and the inner box (3). The urethane foam (4) includes a through passage (8a) leading to the vacuum outlet (6). The vacuum outlet (6) is sealed after the insulation space (1b) filled with the urethane foam (4) is vacuum-evacuated.