Drum Induction Heating Module to Prevent Scale and Coil Deformation

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Solution Overview

Problem

Conventional laundry treatment apparatuses using electric heaters or heat pumps for heating face inefficiencies and safety concerns, such as scale accumulation, poor air-heating efficiency, and high manufacturing costs, while existing induction heating technologies lack concrete implementations for improving efficiency and safety.

Innovation Solution

A laundry treatment apparatus utilizing an induction module with a coil and permanent magnets to heat the drum indirectly, reducing electrical current leakage, preventing coil deformation, and ensuring stable mounting, while controlling heat distribution to prevent overheating and improve drying efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If an electric heater is used to heat wash water, then washing temperature can be increased to improve washing performance, but foreign substances such as scale accumulate on the heater leading to deterioration in performance

Engineering Contradiction:
Improvewash water temperatureVSAvoidheater performance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent introduces an induction heater as an intermediary heating device that heats the drum indirectly through electromagnetic induction, rather than directly heating the wash water. This mediator approach prevents scale accumulation on heating elements while still achieving the desired wash water temperature through thermal conduction from the drum.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the conventional electric resistance heating system with an electromagnetic induction heating system. The induction heater generates an alternating magnetic field that induces eddy currents in the drum, converting electromagnetic energy directly into thermal energy in the drum, thereby eliminating the need for direct contact between heating elements and wash water.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If a heat pump is used to heat air for drying, then drying efficiency is improved, but the structure becomes complicated with high manufacturing costs

Engineering Contradiction:
Improvedrying efficiencyVSAvoidsystem structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent extracts the heating function from the complex heat pump system and implements it separately using an induction heater. By removing the compressor, condenser, evaporator, and expansion valve components, the system achieves air heating through direct electromagnetic induction heating of the drum, which then transfers heat to the air and laundry.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical heat pump cycle with an electromagnetic induction heating system. The induction heater directly converts electrical energy into thermal energy through electromagnetic induction, eliminating the need for mechanical compression and phase change processes, thereby simplifying the system structure while maintaining drying efficiency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Use of energy by moving object

If the coil is positioned close to the drum for efficient heating, then heating efficiency is improved, but the coil may deform due to heat

Engineering Contradiction:
Improveheating efficiencyVSAvoidcoil shape
Core Design Contradiction:
Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent segments the heating system into distinct functional components: the induction coil, the drum, and the mounting structure. By separating the coil from the drum and introducing an air gap, the system maintains heating efficiency through electromagnetic field coupling while preventing direct thermal contact that would cause coil deformation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces air as an intermediary medium between the induction coil and the drum. This air gap acts as a thermal insulator that prevents heat transfer to the coil while allowing electromagnetic field penetration for efficient induction heating, thereby protecting the coil from thermal deformation.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Productivity

If induction heating is used to heat the drum, then washing and drying efficiency are improved, but overheating may occur without proper control

Engineering Contradiction:
Improvewashing and drying efficiencyVSAvoiddrum temperature
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The patent implements a temperature sensing and feedback control system that continuously monitors the drum temperature and adjusts the induction heater power accordingly. When the drum temperature reaches a predetermined threshold, the system automatically reduces or stops heating, preventing overheating while maintaining high washing and drying efficiency through optimized thermal control.

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 solution enhances washing and drying efficiency, prevents overheating, and improves safety by stabilizing the induction module and controlling heat distribution, leading to more effective and safer laundry treatment.

Implementation Method 1

an induction module spaced apart from a circumferential surface of the drum for generating an electromagnetic field to heat the circumferential surface of the drum

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 2

generating an electromagnetic field to heat the circumferential surface of the drum

Methodology Applied
Scientific EffectElectromagnetic field generation: Electromagnetic Induction

Data Source

PatentEP4155453A1Laundry treatment apparatus provided with an induction heater
Publication Date: 2023.03.29 LG ELECTRONICS INC
  • EP4155453A1 patent drawingFigure 1A
  • EP4155453A1 patent drawingFigure 1B
  • EP4155453A1 patent drawingFigure 2A~2B

AI summary

The present invention relates to a laundry treatment apparatus and, more particularly, to a laundry treatment apparatus for directly heating a drum accommodating clothes. According to an embodiment of the present disclosure, provided is a laundry treatment apparatus comprising: a tub; a drum rotatably disposed inside the tub for receiving laundry therein, wherein the drum is made of a metal material; and an induction module disposed on the tub to be spaced from a circumferential surface of the drum for generating an electromagnetic field to heat the circumferential surface of the drum, wherein the induction module is characterized by: a coil formed of wires, wherein the coil generates a magnetic field when an electric current is applied thereto, and, a base housing mounted on an outer circumferential face of the tub, the base housing comprises fixing ribs that protrude upward from a bottom surface of the base housing and that define coil slots configured to receive the wires, wherein the coil has a track shape with a long axis extending in a front-rear direction of the drum.