Oven Muffle Taphole Welding for Corrosion-Resistant Wall Joints

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Solution Overview

Problem

Conventional household appliance wall arrangements face challenges in achieving a durable and robust fastening of wall parts, particularly in appliances like ovens and dishwashers, where weld seams are prone to corrosion and dirt ingress, and accessibility issues complicate the attachment process.

Innovation Solution

A method involving taphole welding, where one wall part completely penetrates another, forming a weld seam visible on both sides, with a collecting space for weld material, ensuring a robust, gap-free joint and simplified attachment, especially suitable for oven muffle components, using plasma welding for high precision and corrosion resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wall parts are welded together with conventional welding methods, then the attachment is achieved, but the weld seams are prone to corrosion and dirt ingress, reducing reliability

Engineering Contradiction:
Improvedurability of weld connectionVSAvoidcorrosion and dirt ingress at weld seams
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

One wall part is inserted into the other wall part to form a nested arrangement, creating a collection chamber that captures weld material and prevents corrosion and dirt ingress at the weld seam interface

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The weld material that would otherwise create vulnerable seams is redirected to flow into the collection chamber formed by the nested wall parts, transforming the harmful weld spillage into a beneficial sealing element that protects the joint

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Manufacturing precision

If complete penetration welding is performed to achieve robust weld joints, then weld quality improves, but the complexity of the welding process increases

Engineering Contradiction:
Improveweld quality and uniformityVSAvoidwelding process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The nested wall part arrangement is prepared in advance to form the collection chamber, which guides the weld material flow and simplifies the welding process by providing a predetermined path for complete penetration welding

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The collection chamber acts as an intermediary structure that facilitates complete penetration welding by capturing and directing weld material, making the complex welding process more controllable and repeatable

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If wall parts are attached with overlapping sections to improve stability, then joint strength increases, but accessibility for welding becomes more difficult

Engineering Contradiction:
Improvejoint stabilityVSAvoidaccessibility for welding
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

Instead of making the welding side accessible, the design inverts the approach by allowing welding from the interior side where the welding device can access the overlapping section, while the exterior maintains a clean appearance

Inventive Principle:
Principle #13The other way round (Inversion)

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 method achieves a high-quality, robust weld connection with uniform clamping forces, enhancing the durability and corrosion protection of the appliance compartment while maintaining a low visual and cleaning impact, and simplifying the attachment of rear wall parts with poor accessibility.

Implementation Method 1

the wall parts are welded together

Methodology Applied
Scientific EffectWelding: Welding

Implementation Method 2

using plasma welding for high precision and corrosion resistance

Methodology Applied
Scientific EffectPlasma welding: Plasma

Implementation Method 3

a collection space for weld material

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP2097676B2Domestic appliance wall arrangement and method for fixing wall parts in a domestic appliance
Publication Date: 2023.06.07 BSH HAUSGERATE GMBH
  • EP2097676B2 patent drawingFigure 1
  • EP2097676B2 patent drawingFigure 2
  • EP2097676B2 patent drawingFigure 3a~3b

AI summary

The invention relates to a domestic appliance, in particular, an oven, comprising at least two wall parts (16, 18) of the muffle, fixed together by means of a welded joint (34) and may concern a first tubular and a second wall piece in the form of a back wall of the oven muffle. According to the invention, a long-lasting and robust connection of the wall pieces to each other may be achieved, wherein the welded joint (34) extends through at least one of the wall pieces (18).