Decentered Sensor Induction Heating for Temperature Accuracy

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Solution Overview

Problem

Conventional induction heating devices suffer from reduced thermal responsiveness and temperature sensing accuracy when the to-be-heated object is not placed directly above the sensor, leading to potential overheating and deformation of objects like empty pans.

Innovation Solution

The induction heating device features a sensor positioned decentered from the center of the heating coil, allowing for non-contact temperature sensing of the to-be-heated object's higher temperature areas, with a display unit on the top plate to guide users in placing the object correctly above the sensor, enhancing measurement accuracy and preventing abnormal heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the sensor is placed at the center of the heating coil to improve uniform heating and prevent excessive temperature increase, then thermal responsiveness and temperature sensing accuracy deteriorate when the to-be-heated object is not placed directly above the sensor

Engineering Contradiction:
Improveuniform heatingVSAvoidtemperature sensing accuracy
Core Design Contradiction:
Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The patent applies asymmetry by deliberately positioning the sensor off-center relative to the heating coil. Specifically, the sensor is placed at a position that is decentered from the center of the heating coil in a direction vertical to the front side, creating an asymmetric configuration that optimizes temperature sensing accuracy while maintaining uniform heating performance.

Inventive Principle:
Principle #4Asymmetry

2Measurement precision

If the sensor is positioned to sense higher temperature areas of the to-be-heated object, then temperature sensing accuracy improves, but the user may not be able to visually recognize the sensor position and place the object correctly

Engineering Contradiction:
Improvetemperature sensing accuracyVSAvoiduser ability to place object correctly
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent uses visual indication (display) to show the sensor position on the top plate. The display unit presents the decentered sensor position in an easy-to-understand manner, using visual cues such as color or light indicators to guide users in placing the to-be-heated object at the appropriate position above the sensor.

Inventive Principle:
Principle #32Color changes

3Ease of manufacture

If the sensor is placed at the center of the heating coil, then the configuration is simple and manufacturing is easier, but thermal responsiveness deteriorates when the object is not properly positioned

Engineering Contradiction:
Improvesensor placement simplicityVSAvoidthermal responsiveness
Core Design Contradiction:
Ease of manufactureVSSpeed

Solution Approach 1:

The patent implements an asymmetric sensor placement that is decentered from the heating coil center. This asymmetric configuration enhances thermal responsiveness by positioning the sensor to detect temperature changes more effectively, while the manufacturing complexity remains manageable due to the straightforward implementation of the decentered position.

Inventive Principle:
Principle #4Asymmetry

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 configuration improves temperature sensing accuracy, prevents overheating, and ensures user-friendly operation by visually indicating the sensor's position, thus securely placing the object above the sensor for precise temperature control.

Implementation Method 1

heating coil 204 for induction-heating to-be-heated object 202

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

heating coil 204 for induction-heating to-be-heated object 202

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 3

Sensor 205 is pressure-welded to a back face of top plate 203 corresponding to a lower part of to-be-heated object 202

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

Sensors 205 are a heat sensitive element such as a thermistor

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentEP1942704B1Induction heating device
Publication Date: 2019.03.06 PANASONIC HOLDINGS CORP
  • EP1942704B1 patent drawingFigure 1A~1B
  • EP1942704B1 patent drawingFigure 2A~2C
  • EP1942704B1 patent drawingFigure 3

AI summary

An induction heating device is provided that can realize an accrete sensing of the temperature of a to-be-heated object and that is user-friendly. To realize this, the induction heating device includes a sensor for sensing the temperature of the to-be-heated object and can carry out a heating operation only when it is determined that the to-be-heated object exists above the sensor. A display having a circular design and characters for example that shows the position of this sensor is provided on a top plate of the induction heating device.