Induction Heating System With Multi-Sensor Temperature Feedback

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Solution Overview

Problem

Induction heating systems often fail to heat work pieces uniformly due to the reliance on a single temperature feedback device, leading to inconsistent material property changes, especially in applications like post-weld stress relief where uniform heating is crucial.

Innovation Solution

A system that utilizes multiple temperature feedback devices to provide signals for controlling the induction heating process, allowing for accurate temperature measurement and adjustment across the work piece, ensuring uniform heating and adherence to a desired heating profile.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a single temperature feedback device is used to control induction heating, then the system is simple to operate, but the heating uniformity across the work piece deteriorates

Engineering Contradiction:
Improvesystem simplicityVSAvoidheating uniformity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The work piece is divided into multiple monitoring zones, each equipped with its own temperature feedback device (thermocouple). This segmentation allows independent temperature measurement at different locations, enabling the controller to detect and correct temperature variations across the work piece surface, thereby achieving uniform heating while maintaining system simplicity through modular temperature monitoring.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If multiple temperature feedback devices are used to improve heating uniformity, then the temperature measurement accuracy improves, but the device complexity increases

Engineering Contradiction:
Improveheating uniformityVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Multiple temperature feedback devices are merged into a single integrated control system. The controller receives temperature signals from all thermocouples simultaneously and processes them together to determine the appropriate heating power level. This merging approach maintains heating uniformity through comprehensive temperature monitoring while reducing operational complexity by providing unified control despite multiple sensors.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If a single temperature feedback device is used, then the system structure is simple, but the temperature control precision deteriorates

Engineering Contradiction:
Improvesystem structureVSAvoidtemperature measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The temperature monitoring is extended from a single-point measurement to multi-dimensional spatial measurement across the work piece surface. By placing thermocouples at different locations (e.g., center and edge regions), the system captures temperature distribution in multiple spatial dimensions, providing comprehensive temperature control precision while maintaining relatively simple system structure through straightforward sensor placement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 system achieves more precise and uniform heating by analyzing data from multiple temperature feedback devices, preventing over- or under-heating and ensuring consistent material property changes across the work piece.

Implementation Method 1

A varying magnetic field is produced by transmitting an alternating current through an induction heating device. A work piece located inside or in close proximity to the induction heating device is exposed to the varying magnetic field, inducing movement of electrons and causing a flow of eddy currents in the work piece.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

inducing movement of electrons and causing a flow of eddy currents in the work piece. These eddy currents and resistance to current flow within the work piece cause the temperature of the work piece to rise.

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 3

These eddy currents and resistance to current flow within the work piece cause the temperature of the work piece to rise.

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP1889517B1Induction heating system having multiple temperature input control
Publication Date: 2015.01.21 ILLINOIS TOOL WORKS INC
  • EP1889517B1 patent drawingFigure 1~2
  • EP1889517B1 patent drawingFigure 3a~5
  • EP1889517B1 patent drawingFigure 6

AI summary

A system and method for inductively heating a work piece. The induction heating system is coupleable to a plurality of temperature feedback devices operable to provide a signal representative of work piece temperature. The induction heating system is operable to control the output of the induction heating system based on the plurality of signals representative of work piece temperature received from the plurality of temperature feedback devices.