Laundry Drum Induction Coil Layout for Uniform Heating

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Solution Overview

Problem

Conventional laundry machines face inefficiencies in heating laundry without heating wash water, leading to energy waste and uneven drying of large or entangled loads, with potential overheating and interference with other components.

Innovation Solution

A laundry apparatus with an induction unit that uses a coil to generate an electromagnetic field, directly heating the drum and laundry without submerging it in hot water, featuring a coil arrangement that prevents overheating and interference, and includes a controller to manage current flow and temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If an auxiliary heater is provided to heat wash water indirectly, then the temperature of laundry is raised, but energy consumption increases and wash water must be supplied to submerge laundry

Engineering Contradiction:
Improvetemperature of laundryVSAvoidenergy consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The patent extracts the heating function from the wash water and applies it directly to the drum. The induction heating coil generates electromagnetic fields that induce eddy currents in the conductive drum, heating the drum surface directly without needing to heat wash water. This separates the heating action from the wash water, eliminating the requirement to submerge laundry while reducing energy consumption.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The conductive drum acts as an intermediary between the induction heating coil and the laundry. The electromagnetic field from the coil induces currents in the drum, which then transfers heat to the laundry through contact. This intermediary mechanism enables direct heating of laundry without heating large volumes of wash water.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If heated air is supplied to dry laundry, then laundry is dried, but heated air is not uniformly supplied to large or entangled laundry loads

Engineering Contradiction:
Improvedrying efficiencyVSAvoiduniformity of heating
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical convection system (heated air circulation) with an electromagnetic induction system. The induction heating coil generates electromagnetic fields that directly induce heating in the conductive drum, eliminating the need for air circulation mechanics. This substitution ensures uniform heating regardless of laundry arrangement since the electromagnetic field penetrates and heats the drum surface uniformly, which in turn heats the laundry uniformly.

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

3Temperature

If a coil is used for induction heating, then direct heating of drum is achieved, but the coil may overheat due to resistance and generate magnetic field interference

Engineering Contradiction:
Improveheating efficiencyVSAvoidcoil overheating and magnetic field interference
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The conductive drum serves as an intermediary that converts electromagnetic energy to thermal energy through eddy currents. The coil generates the electromagnetic field, which induces currents in the drum, and the drum's resistance generates heat uniformly distributed throughout its surface. This intermediary arrangement prevents coil overheating because the coil itself does not carry high current continuously - instead, it generates alternating magnetic fields that induce currents in the drum.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The induction heating system uses alternating current to generate periodically reversing magnetic fields. This periodic action prevents continuous overheating of the coil because the alternating nature of the current allows for cooling periods and distributes thermal load. The alternating magnetic field also ensures uniform induction of eddy currents throughout the drum, preventing localized overheating.

Inventive Principle:
Principle #19Periodic action

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

Enables efficient laundry soaking, sterilization, and drying without heating wash water, reducing energy consumption and ensuring uniform heating of large or entangled loads, while preventing coil overheating and short circuits.

Implementation Method 1

an induction unit provided in an outer circumferential surface of the tub and heating the drum by generating an electromagnetic field

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a coil generating an eddy current in the drum by generating a magnetic field, using an electric current supplied thereto

Methodology Applied
Scientific EffectEddy current: Eddy Currents

Implementation Method 3

a coil generating an eddy current in the drum by generating a magnetic field, using an electric current supplied thereto

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3287558B1Laundry apparatus
Publication Date: 2019.04.17 LG ELECTRONICS INC
  • EP3287558B1 patent drawingFigure 1(a)~2(b)
  • EP3287558B1 patent drawingFigure 3(a)~4(b)
  • EP3287558B1 patent drawingFigure 5(a)~5(c)

AI summary

There is disclosed a laundry apparatus comprising a cabinet (10); a tub (20, 30) provided in the cabinet (10) and defining an internal space, with an opening (22) formed in a front; a drum (30, 40) rotatably provided in the internal space of the tub (20, 30) and made of a conductor; and an induction unit (60, 70A, 70B, 70, 71A, 71) provided in an outer circumferential surface of the tub (20, 30) and heating the drum (30, 40) by generating an electromagnetic field, wherein the induction unit (60, 70A, 70B, 70, 71A, 71) comprises a coil (71, 74) generating an eddy current in the drum (30, 40) by generating a magnetic field, using an electric current supplied thereto; and a coil arranging portion (74) provided in the outer circumferential surface of the tub (20, 30) and guiding the coil (71, 74) to be wound around front and rear portions of the tub (20, 30) at least one time, spaced a preset distance apart from each other.