Laundry Machine Induction Heater for Drum-Surface Steam Generation

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Solution Overview

Problem

Conventional laundry machines with external or built-in steam generators face issues such as high material costs, energy inefficiency, limited steam generation during drum motion or spin-drying, and complex configurations due to multiple heating sources, which restrict their performance in washing, drying, and refreshing processes.

Innovation Solution

A laundry machine employing an induction heater to generate steam by spraying water onto the outer surface of a heated drum, eliminating the need for separate heating sources and connection hoses, and using a single inverter drive to control the induction heaters for efficient steam generation and supply.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an external steam generator is provided, then high-quality steam can be generated freely, but material cost increases and installation structure is restricted

Engineering Contradiction:
Improvesteam generation qualityVSAvoidinstallation structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the steam generation function with the existing drum structure by integrating an induction heater directly onto the drum surface. This eliminates the need for separate external steam generators and their associated complex installation structures including water supply systems, heat generators, sensors, safety devices, and discharge parts. The induction heater is coupled to the drum through a heat transfer medium, allowing steam generation to be embedded within the existing laundry machine architecture.

Inventive Principle:
Principle #5Merging (Combining)

2Quantity of substance

If steam is generated by conventional heater with water supply, then steam can be produced, but energy efficiency decreases due to large amount of wash water heating

Engineering Contradiction:
Improvesteam generation capabilityVSAvoidenergy efficiency
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent extracts the steam generation process from the traditional water-heating approach and implements it directly on the drum surface. Instead of heating large amounts of wash water in the tub and then transferring heat, the induction heater directly heats the drum, which then transfers heat to a small amount of water or moisture on the laundry. This extraction of the heating function from the bulk water and concentration of heat at the drum-laundry interface dramatically improves energy efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If heater protection water level is maintained, then heater is protected, but steam generation time is limited and cannot operate during drum driving or spin-drying

Engineering Contradiction:
Improveheater protectionVSAvoidsteam generation availability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the conventional electrical heater submerged in water with an induction heater that couples to the drum through a heat transfer medium. This substitution allows the heating system to operate in air or with minimal moisture rather than requiring immersion in water. The induction heater generates electromagnetic fields that induce currents in the conductive drum, transferring heat without direct water contact, thereby enabling operation during drum rotation, spin-drying, and other phases where water level cannot be maintained.

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

4Adaptability or versatility

If separate heating sources are provided for wash water heating and steam generation, then both functions are achieved, but configuration becomes complicated and material cost increases

Engineering Contradiction:
Improveheating function coverageVSAvoidconfiguration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements multi-functionality by designing the induction heater system to perform both wash water heating and steam generation through a single integrated component. The induction heater coupled to the drum can heat the drum surface for steam generation and also heat the wash water indirectly through the drum structure. This universal heating source eliminates the need for separate heating elements for different functions, simplifying the overall configuration and reducing material costs.

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 reduces manufacturing costs, enhances energy efficiency, allows for simultaneous steam generation and supply, and optimizes steam distribution within the drum, improving washing, drying, and refreshing performance while minimizing operating time.

Implementation Method 1

an induction heater mounted on the circumferential surface of the tub and configured to heat a heating surface of the drum facing the induction heater on an outer surface of the drum

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 2

a spray nozzle configured to spray water onto the heating surface of the drum to generate steam

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3674471B1Laundry machine having induction heater
Publication Date: 2023.05.31 LG ELECTRONICS INC
  • EP3674471B1 patent drawingFigure 1
  • EP3674471B1 patent drawingFigure 2
  • EP3674471B1 patent drawingFigure 3

AI summary

Disclosed herein is a laundry machine. More particularly, a laundry machine for generating steam by an induction heater and a control method thereof are disclosed. According to an embodiment, the laundry machine may include a tub, a drum rotatably arranged in the tub to accommodate an object and provided with a through hole on an outer circumferential surface, an induction heater provided to the tub and configured to heat a heating surface of the drum opposing the induction heater on an outer surface of the drum, a motor driven to rotate the drum, a spray nozzle configured to spray water onto the heating surface of the drum opposing and heated by the induction heater to generate steam, and a processor configured to rotate the drum such that the steam is introduced into the drum through the through hole of the drum in a space between the tub and the drum.