Method for producing composite thermal insulator, method for producing water heater, and composite thermal insulator

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Solution Overview

Problem

Conventional methods for producing composite thermal insulators degrade the thermal insulation performance of vacuum thermal insulators due to gas permeation from the edges and lack of unity between the vacuum insulator and the heat insulating foam, leading to inefficient thermal insulation.

Innovation Solution

A method involving a vacuum thermal insulator with a weld portion along its outer periphery, where the edges are covered with a first heat insulating foam and then a second heat insulating foam is formed to cover both the first foam and the insulator, enhancing adhesion and preventing gas permeation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the periphery of the vacuum thermal insulator is heated and pressurized in forming the heat insulating foam, then the heat insulating foam can be formed to cover the vacuum thermal insulator, but gas permeation from the edges of the vacuum thermal insulator to inside is facilitated, degrading the thermal insulation performance

Engineering Contradiction:
Improveheat insulating foam formationVSAvoidthermal insulation performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The edges of the vacuum thermal insulator are covered with the heat insulating foam before the heating and pressurization process. This preliminary covering prevents gas from permeating into the vacuum thermal insulator during the subsequent foam formation process, thus maintaining thermal insulation performance while still allowing the heat insulating foam to be formed effectively.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the heat insulating foam is foamed in advance and fitted around the vacuum thermal insulator, then the foam can be prepared beforehand, but a gap is formed between the vacuum thermal insulator and the heat insulating foam, resulting in insufficient fixation and lack of unity

Engineering Contradiction:
Improvefoam preparation efficiencyVSAvoidunity between vacuum thermal insulator and foam
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The heat insulating foam is separated into two distinct parts: a first heat insulating foam that covers the edges of the vacuum thermal insulator, and a second heat insulating foam that covers the main body. This separation allows each foam part to perform its specific function - the first foam prevents gas permeation and provides fixation, while the second foam provides additional insulation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Different regions of the vacuum thermal insulator are covered with heat insulating foam having different properties or positions. The first heat insulating foam is specifically applied to the edges where gas permeation is a concern, while the second heat insulating foam covers the main body. This localized approach ensures optimal performance in each region.

Inventive Principle:
Principle #3Local quality

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 approach significantly improves the thermal insulation performance and integrity of the composite thermal insulator by reducing gas permeation and ensuring a tight seal between the vacuum insulator and the foam, outperforming conventional techniques.

Implementation Method 1

edges, i.e., outer peripheral portions, of the vacuum thermal insulator have a higher gas permeability than other parts, if a periphery of the vacuum thermal insulator is heated and pressurized in forming the heat insulating foam, gas permeation from the edges of the vacuum thermal insulator to inside is facilitated

Methodology Applied
Scientific EffectGas permeation prevention: Permeation

Implementation Method 2

a second heat insulating foam is formed to cover the first heat insulating foam placed in the first step and at least part of the vacuum thermal insulator, enhancing adhesion and preventing gas permeation

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 3

the vacuum thermal insulator having vacuum-sealed inside

Methodology Applied
Scientific EffectVacuum insulation: Vacuum

Data Source

PatentEP3141370B1Method for producing composite thermal insulator, method for producing water heater, and composite thermal insulator
Publication Date: 2023.05.24 MITSUBISHI ELECTRIC CORP
  • EP3141370B1 patent drawingFigure 1~2
  • EP3141370B1 patent drawingFigure 3
  • EP3141370B1 patent drawingFigure 4(a)~4(f)

AI summary

To provide a method for producing a composite thermal insulator (1), a method for producing a water heater (25), and the composite thermal insulator (1) which can limit degradation of thermal insulation performance of a vacuum thermal insulator (2) more efficiently than the conventional techniques, achieving improved integrity. The present invention provides a method for producing a composite thermal insulator (1) including a vacuum thermal insulator (2), the vacuum thermal insulator (2) comprising a core (2a) and an enclosure (2b) configured to wrap the core (2a) and include a weld portion (5) which extends along an outer periphery of the core (2a) and at which portions of the enclosure (2b) are welded together, the vacuum thermal insulator(2) having vacuum-sealed inside, the method including: a first step of covering edges (7) of the vacuum thermal insulator (2) including the weld portion (5) with a first heat insulating foam (3) foamed in advance and placing the first heat insulating foam (3) along the outer periphery of the core; and a second step of forming a second heat insulating foam (4) configured to cover the first heat insulating foam (3) placed in the first step and at least part of the vacuum thermal insulator (2).