Composite Induction Vessel Bottom for Corrosion-Resistant Heating

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing cooking vessels for induction heating face inefficiencies due to materials like stainless steel, which require precise manufacturing, are costly, and prone to corrosion, while spray-coated iron layers lack adhesion and sufficient thickness for optimal induction properties.

Innovation Solution

A cooking vessel with a ferromagnetic bottom member made from materials like iron or stainless steel, coated with a thin layer of electrically conductive materials like aluminum, magnesium, or copper for improved induction and corrosion resistance, allowing for pressure or impact welding and surface treatments for enhanced mechanical and chemical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If stainless steel is used for the bottom plate, then moisture resistance and washing resistance are improved, but induction heating efficiency deteriorates and manufacturing cost increases

Engineering Contradiction:
Improvemoisture resistanceVSAvoidinduction heating efficiency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The bottom of the cooking vessel uses a composite structure combining ferromagnetic material (for induction heating efficiency) with a protective coating layer (for moisture and corrosion resistance). This resolves the contradiction by integrating materials with complementary properties rather than relying on stainless steel alone.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The protective coating is applied specifically to the bottom surface that contacts food and moisture, while the ferromagnetic base layer maintains optimal thickness for induction heating. This localized application of protective properties allows each material to perform its primary function effectively.

Inventive Principle:
Principle #3Local quality

2Reliability

If stainless steel is used for the bottom plate, then moisture resistance is improved, but manufacturing cost increases

Engineering Contradiction:
Improvemoisture resistanceVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The composite bottom structure uses a cost-effective ferromagnetic base material combined with a thin protective coating layer, achieving moisture resistance without the high material costs of solid stainless steel construction.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The protective coating acts as a sacrificial or maintainable layer that protects the underlying ferromagnetic material, allowing the use of less expensive base materials while maintaining durability through coating renewal or replacement if needed.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Ease of manufacture

If spray coating method is used for iron layer, then manufacturing cost is reduced, but adhesion and layer thickness consistency deteriorate

Engineering Contradiction:
Improvemanufacturing costVSAvoidlayer adhesion
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The coating process parameters (such as coating method, thickness control, and application technique) are optimized to achieve reliable adhesion and consistent thickness. This may involve transitioning from spray coating to alternative methods like electroplating, physical vapor deposition, or controlled dip coating that provide better adhesion and uniformity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Surface preparation steps are performed before coating application to enhance adhesion, such as surface cleaning, roughening, or applying primer layers. This preliminary treatment ensures that the coating adheres properly to the ferromagnetic base material.

Inventive Principle:
Principle #10Preliminary action

4Use of energy by moving object

If iron layer thickness is increased to 0.6 mm for sufficient induction properties, then induction heating efficiency is improved, but manufacturing complexity and coating reliability worsen

Engineering Contradiction:
Improveinduction heating efficiencyVSAvoidcoating process complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The coating process parameters are optimized to achieve reliable adhesion and consistent thickness. This may involve transitioning from spray coating to alternative methods like electroplating, physical vapor deposition, or controlled dip coating that provide better adhesion and uniformity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Surface preparation steps are performed before coating application to enhance adhesion, such as surface cleaning, roughening, or applying primer layers. This preliminary treatment ensures that the coating adheres properly to the ferromagnetic base material.

Inventive Principle:
Principle #10Preliminary action

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 solution enables efficient induction heating with improved thermal conductivity, reduced manufacturing costs, and enhanced durability and safety, while maintaining the benefits of induction cooking, including reduced weight and stability during heating.

Implementation Method 1

Induction heating is based on magnetic hysteresis losses occurring in material at the bottom of a cooking vessel, which are converted to heat energy

Methodology Applied
Scientific EffectMagnetic hysteresis losses: Magnetic Hysteresis

Implementation Method 2

ferromagnetic bottom member is coated by at least one layer of material which conducts electricity

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2503927B1Cooking vessel applicable for induction heating and method for manufacturing thereof
Publication Date: 2014.11.12 FISKARS HOME OY
  • EP2503927B1 patent drawingFigure 1~3b
  • EP2503927B1 patent drawingFigure 3c~4

AI summary

The invention relates to a cooking device, particularly to a cooking vessel, such as kettle, frying pan or cooking pot, which has a bottom part suitable for heating by induction. In solutions known before, an attachment of ferromagnetic plate, placed at the bottom, to blank container is multistage, demanding exceptional precision and/or non-reliable. In addition, in solutions known before, stainless steel is used; to which use some disadvantages are related. In the present invention a plate is used as ferromagnetic member, which is coated, at least from its one surface, by another material, such as aluminium. Ferromagnetic piece is attached e.g. by pressure welding to blank container. In solution provided by the invention it is possible to use an iron plate as ferromagnetic material.