Induction Coil Spacing and Frequency for Uniform Metal Heating

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Solution Overview

Problem

Existing induction heating devices for metal goods suffer from reduced electrical efficiency due to maintaining a standard vertical safety distance, which compromises heating homogeneity, especially in edge regions, leading to overheating or undercooling.

Innovation Solution

An induction heating device with at least one first and one second coil, arranged to convey metal through a space between them, where the power supply unit supplies alternating current and voltage to achieve a penetration depth of current-carrying layers less than or equal to 0.7 times the metal thickness, optimizing coil spacing and frequency to enhance heating homogeneity and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a standard vertical safety distance is maintained between coils and metal goods, then coil damage is prevented, but electrical efficiency is significantly reduced

Engineering Contradiction:
Improvecoil protectionVSAvoidelectrical efficiency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by making the coil spacing adjustable rather than fixed. The distance between coils can be dynamically adapted to match the thickness of different metal goods, allowing optimal heating efficiency while maintaining safety through controlled movement and positioning mechanisms

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the parameter of coil spacing from a fixed standard distance to a variable parameter that can be adjusted according to metal good thickness. This parameter change enables optimization of electrical efficiency while maintaining protective safety margins through controlled adjustment

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a standard vertical safety distance is maintained between coils and metal goods, then coil protection is ensured, but heating homogeneity deteriorates

Engineering Contradiction:
Improvecoil protectionVSAvoidheating homogeneity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The adjustable coil spacing allows the system to dynamically optimize heating homogeneity by reducing distances for thicker metals and maintaining appropriate distances for thinner metals, preventing both overheating and undercooling while protecting coils through controlled positioning

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention applies local quality by enabling different coil spacing configurations for different regions and thicknesses of metal goods. The system can locally adjust spacing to match specific areas of the metal, ensuring uniform heating across the entire workpiece while maintaining protective distances where needed

Inventive Principle:
Principle #3Local quality

3Use of energy by moving object

If coil spacing is reduced to improve electrical efficiency, then heating efficiency increases, but risk of coil damage increases

Engineering Contradiction:
Improveelectrical efficiencyVSAvoidcoil protection
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The system uses dynamic adjustment mechanisms to reduce coil spacing only when and where needed for optimal efficiency, while maintaining protective spacing through controlled movement and positioning, thus achieving both efficiency and protection simultaneously

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the spacing parameter from a conservative fixed value to an optimized variable value that adapts to specific heating requirements, allowing reduced spacing for efficiency while maintaining safety through controlled parameter adjustment and monitoring

Inventive Principle:
Principle #35Parameter changes

4Device complexity

If fixed coil spacing is used to simplify device design, then device complexity is reduced, but heating homogeneity deteriorates

Engineering Contradiction:
Improvecoil arrangementVSAvoidheating homogeneity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent introduces dynamic adjustment capability that adds controlled complexity to achieve better heating homogeneity. The adjustable spacing mechanism allows optimization of heating uniformity across different metal thicknesses while maintaining manageable system complexity through standardized adjustment components

Inventive Principle:
Principle #15Dynamics

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 achieves high electrical efficiency and increased heating homogeneity across the thickness and width of the metal, preventing overheating at edges by controlling current density and penetration depth.

Implementation Method 1

the power supply unit is configured to supply the first coil and the second coil with alternating current and/or alternating voltage, such that a penetration depth δ of current-carrying layers of the conveyed metal is less than or equal to 0.7 times the thickness extent of the conveyed metal

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

induction heating device for heating a metal material conveyed in a conveying direction

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 3

The current density of a current induced by the alternating magnetic fields of the first and second coils in a metal material conveyed through the space between the first and second coils

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4635256B1Induction heating device, production line, use of an induction heating device of this kind, and use of a production line of this kind
Publication Date: 2025.11.26 SMS GROUP GMBH
  • EP4635256B1 patent drawingFigure 1
  • EP4635256B1 patent drawingFigure 2
  • EP4635256B1 patent drawingFigure 3

AI summary

The invention relates to an induction heating device (1) for heating a metal material (40) conveyed in a conveying direction (R1), wherein the induction heating device (1) has at least one inductor (2), having at least one first coil (10) and at least one second coil (20), wherein the first coil (10) and the second coil (20) are arranged spaced apart from each other in a spacing direction (R2) and at least partially delimit a clearance, so that a metal material (40) conveyed in the conveying direction (R1) is conveyed at least partially through the clearance between the first coil (10) and the second coil (20), and at least one energy supply means (30), which is electrically connected to the first coil (10) and the second coil (20).