Clothes treatment apparatus

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Solution Overview

Problem

Existing clothes treatment apparatuses using induction heaters face challenges in accurately estimating the temperature of the drum, especially due to the influence of the magnetic field and the need for power interruption to measure resonance frequency.

Innovation Solution

A clothes treatment apparatus is designed with a movable magnet and a fixed coil, where the magnet's residual magnetic flux density changes with temperature, inducing a counter electromotive force in the coil, allowing for continuous temperature estimation without power interruption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If resonance frequency measurement method is used to estimate drum temperature, then temperature can be estimated without power interruption, but measurement precision is insufficient with error of ±10°C or more

Engineering Contradiction:
Improvepower interruption timeVSAvoidtemperature estimation accuracy
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The patent changes the measurement parameter from resonance frequency to inductance. By measuring the inductance of the induction heater coil, which changes with drum temperature, the system achieves both continuous operation and improved measurement precision of ±5°C or less.

Inventive Principle:
Principle #35Parameter changes

2Loss of time

If heat sensor is disposed between drum and tank to sense temperature, then temperature can be continuously monitored, but measurement precision is insufficient because water or air temperature changes slowly and does not exactly reflect drum temperature changes

Engineering Contradiction:
Improvetemperature monitoring continuityVSAvoiddrum temperature estimation accuracy
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The patent uses the induction heater coil as an intermediary element to measure drum temperature. The coil's inductance changes in response to drum temperature, providing a direct measurement that reflects actual drum temperature changes rather than relying on the slower-changing water or air temperature.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If inductance measurement method is used, then temperature estimation precision improves to ±5°C, but device complexity increases due to additional measurement circuitry

Engineering Contradiction:
Improvetemperature estimation accuracyVSAvoidmeasurement circuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The induction heater coil serves multiple functions: it heats the drum and simultaneously acts as the sensing element for temperature measurement through its inductance changes. This eliminates the need for separate temperature sensors and reduces overall device complexity while achieving ±5°C or better measurement precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution enables accurate and continuous temperature estimation of the drum, minimizing the impact of the magnetic field and structural gaps, and maintaining efficiency by avoiding power interruptions.

Implementation Method 1

the magnet's residual magnetic flux density changes with temperature, inducing a counter electromotive force in the coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

an induction heater disposed outside the drum and heating the drum

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Data Source

PatentEP4123076B1Clothes treatment apparatus
Publication Date: 2025.03.05 LG ELECTRONICS INC
  • EP4123076B1 patent drawingFigure 1~3
  • EP4123076B1 patent drawingFigure 4~5
  • EP4123076B1 patent drawingFigure 6~7

AI summary

Disclosed is a clothes treatment apparatus. The clothes treatment apparatus of the present disclosure may comprise: a cabinet; a drum rotatably provided in the cabinet; an induction heater which is disposed outside the drum and heats the drum; a magnet which is fixed to the drum and of which a residual magnetic flux density changes depending on temperature; and a coil fixed to the outside of the drum and disposed at a position overlapping the magnet in the longitudinal direction of the central axis of rotation of the drum.