Vacuum Insulation Core Composition for Low Gaseous Conduction

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Solution Overview

Problem

Existing vacuum insulated structures for appliances face challenges in achieving high thermal insulation due to significant gaseous conduction through large interstitial volumes and gaseous pores, which can lead to vacuum bow and deformation under pressure differentials.

Innovation Solution

A method involving the use of hollow glass spheres, anchor materials, and silica-based materials to create a super-insulating core material with minimal gaseous pores, where the anchor materials like glass fibers and perlite occupy interstitial spaces and the silica-based materials are attached or entrapped, reducing gaseous conduction and enhancing structural density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional insulating materials are used in vacuum insulated structures, then the structure can be manufactured with conventional materials, but significant gaseous conduction through large interstitial volumes leads to poor thermal insulation performance

Engineering Contradiction:
Improvethermal insulation performanceVSAvoidcore material structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a composite core material consisting of hollow glass spheres combined with silica-based material and anchor material. This composite structure reduces gaseous conduction by filling interstitial spaces between spheres, thereby improving thermal insulation performance while maintaining manufacturability through a multi-component formulation approach.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent utilizes a porous core material structure where hollow glass spheres create controlled porosity. The interstitial spaces between spheres are partially filled with silica-based material, creating a hierarchical porous structure that reduces gaseous conduction pathways while maintaining the vacuum insulation effect.

Inventive Principle:
Principle #31Porous materials

2Reliability

If hollow glass spheres are used as core material, then the structure provides good insulating properties, but large interstitial volumes between spheres increase gaseous conduction

Engineering Contradiction:
Improveinsulating propertiesVSAvoidgaseous conduction
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and eliminates the harmful gaseous conduction effect by filling the interstitial spaces between hollow glass spheres with silica-based material. This removes the continuous gaseous pathways that would otherwise conduct heat, while preserving the insulating properties of the hollow spheres.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The silica-based material acts as an intermediary substance that fills the interstitial spaces between hollow glass spheres. This intermediary material blocks direct gaseous conduction pathways while allowing the hollow spheres to maintain their insulating function, effectively mediating between the spheres to reduce heat transfer.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Weight of moving object

If the core material has high porosity to reduce density, then the structure is lighter, but large pores increase gaseous conduction and reduce structural integrity

Engineering Contradiction:
Improvecore material densityVSAvoidgaseous conduction resistance
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent segments the pore structure into two distinct levels: large hollow glass spheres providing macro-level porosity for low density, and small interstitial spaces between spheres filled with silica-based material providing micro-level pore structure. This hierarchical segmentation allows simultaneous achievement of low density and high gaseous conduction resistance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different material qualities to different spatial locations: hollow glass spheres dominate the macrostructure providing low density, while silica-based material locally fills the interstitial spaces to provide gaseous conduction resistance. This local differentiation of material properties resolves the contradiction between density and insulation performance.

Inventive Principle:
Principle #3Local quality

4Object-affected harmful factors

If anchor material is added to occupy interstitial spaces, then gaseous conduction is reduced, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvegaseous conductionVSAvoidmanufacturing process simplicity
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent merges multiple materials (hollow glass spheres, silica-based material, and anchor material) into a single composite core material formulation. This combining approach allows all components to be processed together in one manufacturing cycle, reducing the number of separate manufacturing steps despite the increased material complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The anchor material serves multiple functions simultaneously: it occupies interstitial spaces to reduce gaseous conduction, provides structural support to maintain core integrity, and acts as a binding agent to hold the silica-based material in place. This multi-functionality reduces the need for additional specialized components or processes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 method results in a super-insulating material with gaseous pores of less than one micron, significantly reducing thermal conductivity and resisting compression, thereby maintaining structural integrity and enhancing insulation performance in vacuum insulated structures.

Implementation Method 1

significantly reducing thermal conductivity

Methodology Applied
Scientific EffectGaseous conduction: Conduction (thermal)

Implementation Method 2

super-insulating core material that can be included within vacuum insulated structures

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3800412B1Processes for making a super-insulating core for a vacuum insulating structure
Publication Date: 2024.05.01 WHIRLPOOL CORP
  • EP3800412B1 patent drawingFigure 1
  • EP3800412B1 patent drawingFigure 2
  • EP3800412B1 patent drawingFigure 3~4

AI summary

A method for forming a super-insulating material (10) for a vacuum insulated structure (14) for an appliance (22) includes disposing hollow glass spheres (30) within a rotating drum, wherein a plurality of interstitial spaces (34) are defined between the hollow glass spheres (30). An anchor material (36) is disposed within the rotating drum. The hollow glass spheres (30) and the anchor material (36) are rotated within the rotating drum, wherein the anchor material (36) is mixed with the hollow glass spheres (30) to partially occupy the interstitial spaces (34). A silica-based material (40) is disposed within the rotating drum. The silica-based material (40) is mixed with the anchor material (36) and the hollow glass spheres (30) to define a super-insulating material (10), wherein the silica-based material (40) attaches to the anchor material (36) and is entrapped within the interstitial spaces (34). The silica-based material (40) and the anchor material (36) occupy substantially all of an interstitial volume (42) defined by the interstitial spaces (34).