Liquid-Cooled Induction Coil Preheating for Uniform Weld Temperature

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Solution Overview

Problem

Existing preheating devices for welding are ineffective and inefficient, and they struggle to maintain minimal temperature variation throughout the welding process.

Innovation Solution

A device comprising a liquid-cooled induction coil, a power supply unit, and a cooling unit, which creates a magnetic field to generate eddy currents in the workpiece, allowing for precise control of heat energy transfer and minimal temperature variation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional preheating devices (induction heaters, electrical resistance heaters, torches) are used, then preheating can be achieved, but the heating effectiveness and efficiency are insufficient and temperature variation throughout the workpiece is difficult to control

Engineering Contradiction:
Improvetemperature uniformityVSAvoidpreheating effectiveness
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The induction heating system is segmented into multiple independently controllable heating zones along the workpiece, allowing different temperature levels to be applied to different sections. This segmentation enables precise temperature control and uniformity across the entire workpiece while maintaining effective preheating in each zone.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system employs dynamic control of heating parameters including variable frequency inversion, adjustable power levels, and real-time temperature monitoring. This dynamic adjustment capability allows the system to adapt to different workpiece positions and thermal conditions, ensuring both effectiveness and temperature uniformity throughout the preheating process.

Inventive Principle:
Principle #15Dynamics

2Productivity

If high power is used to heat the workpiece quickly, then preheating efficiency improves, but temperature variation throughout the workpiece increases

Engineering Contradiction:
Improvepreheating speedVSAvoidtemperature variation
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

Different regions of the workpiece receive customized heating parameters tailored to their specific thermal requirements. The system applies local quality control by adjusting power density, heating duration, and frequency based on position, ensuring rapid preheating without excessive temperature variation between different areas of the workpiece.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system incorporates temperature sensors and control circuits that continuously monitor workpiece temperature and provide feedback to the power supply unit. This feedback mechanism allows real-time adjustment of heating power to maintain optimal temperature uniformity while achieving fast preheating rates, preventing both overheating and temperature variation.

Inventive Principle:
Principle #23Feedback

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 device enables effective and efficient preheating of workpieces to a desired temperature with minimal temperature variation, ensuring high welding quality and precise control over heat energy transfer.

Implementation Method 1

An induction heater comprises induction coils for creating a magnetic field that generates eddy currents within the workpiece, thus heating the workpiece internally

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

creating a magnetic field that generates eddy currents within the workpiece, thus heating the workpiece internally

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 3

An induction heater comprises induction coils for creating a magnetic field that generates eddy currents within the workpiece, thus heating the workpiece internally

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 4

a cooling unit configured to convey cooling liquid through the liquid-cooled induction coil

Methodology Applied
Scientific EffectConvection cooling: Convection

Data Source

PatentEP4518580A1Device and method for preheating a workpiece to be welded
Publication Date: 2025.03.05 PEMAMEK
  • EP4518580A1 patent drawingFigure 1~2
  • EP4518580A1 patent drawingFigure 3~4
  • EP4518580A1 patent drawing

AI summary

The present invention relates to a device (100) and a method for preheating a workpiece (200) to be welded. The device (100) comprises a liquid-cooled induction coil (101) arrangeable in connection with the workpiece (200), a power supply unit (102) configured to supply AC power to the liquid-cooled induction coil (101), and a cooling unit (105) configured to convey cooling liquid through the liquid-cooled induction coil (101). The present invention also relates to a welding system.