Multi-Layer Cooking Wall With Thick-Film Heating for Uniform Heat

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Solution Overview

Problem

Existing cooking appliances face challenges in achieving uniform and efficient heating, particularly in rapidly heating and cooling large areas, while also managing thermal expansion and mechanical stress on heating elements.

Innovation Solution

A combination of a multi-layer material wall with a thick-film heater applied directly, allowing for horizontal heat flow and adjustable heating zones, which reduces thermal conductivity and linear expansion coefficients from the heating side to the cooking surface, eliminating the need for compensating layers and enabling energy-efficient and durable cooking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a thick-film heater is applied directly to a multi-layer material wall, then rapid heating and cooling is achieved, but thermal expansion differences cause mechanical stress on the heating elements

Engineering Contradiction:
Improveheating and cooling speedVSAvoidmechanical stress on heating elements
Core Design Contradiction:
SpeedVSStress or pressure

Solution Approach 1:

The patent employs a multi-layer composite wall structure with specific thermal conductivity gradients. The layers are designed with decreasing thermal conductivity from the heating side to the cooking surface, which creates a compensating effect on thermal expansion and reduces mechanical stress on the thick-film heater during rapid temperature changes.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the thermal conductivity parameters of each layer in the multi-layer wall. By carefully selecting and adjusting the thermal conductivity values of different layers, the system achieves rapid heat transfer to the food while simultaneously managing thermal expansion forces to protect the heating elements.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If the entire wall surface is equipped with thick-film heaters, then uniform heating is achieved, but device complexity and cost increase

Engineering Contradiction:
Improvetemperature uniformityVSAvoidheater distribution complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent divides the heating function into segments by placing thick-film heaters only in specific zones rather than covering the entire wall surface. The multi-layer material's horizontal heat flow capability ensures that heat is distributed uniformly across the cooking surface, eliminating the need for complete surface coverage while maintaining temperature uniformity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The multi-layer material acts as an intermediary that receives heat from localized thick-film heaters and distributes it horizontally across the entire cooking surface. This mediator function allows selective heater placement while achieving uniform heating, reducing system complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If thermal conductivity is increased for rapid heating, then heating efficiency improves, but mechanical stress and thermal expansion problems worsen

Engineering Contradiction:
Improveheating efficiencyVSAvoidheating element durability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies different thermal conductivity properties to different regions of the wall structure. The layer adjacent to the heater has higher thermal conductivity for efficient heat absorption, while subsequent layers have progressively lower conductivity to manage thermal expansion and protect heating elements, creating a gradient that balances efficiency and reliability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The multi-layer structure is specifically designed to compensate for thermal expansion effects. By arranging layers with appropriate thermal conductivity and expansion characteristics, the system accommodates thermal growth during rapid heating cycles, preventing damage to the thick-film heaters while maintaining high heating efficiency.

Inventive Principle:
Principle #37Thermal expansion

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 combination results in rapid heating and cooling, improved heat distribution, energy savings, and extended appliance life by reducing mechanical stress and heating temperatures, while maintaining uniform heat input across the cooking surface.

Implementation Method 1

each heating element being in direct contact with the multi-layer material

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the heat flow is distributed horizontally within the multi-layer material due to the horizontal heat flow

Methodology Applied
Scientific EffectHeat flow: Conduction (thermal)

Implementation Method 3

a partial compensation of different coefficients of thermal expansion

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2190259B1Cooking appliance with wall from multi-layered material
Publication Date: 2016.05.04 FRIMA
  • EP2190259B1 patent drawingFigure 1

AI summary

The apparatus (1) has a wall (2) heated in zones using heaters (4, 12) which define a heating element layer (6) in a form of a thick layer applied on the wall. The wall is realized by three multi-layered materials (2a-2c) and forms a base of the apparatus, where heat produced in the zones is diffused through the materials for uniform heating of the wall. The heaters are arranged in a removable manner at the wall using a screwed connection part (14). The materials (2a, 2c) are made of stainless steel and the material (2b) is made of aluminum, aluminum alloy or copper alloy.