Induction-Heated Ferromagnetic Drum for Low-Water Washing Machines

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Solution Overview

Problem

Conventional washing machines require free liquor for heating, which leads to energy inefficiencies and increased water consumption, especially when heating damp laundry without additional water.

Innovation Solution

The method involves inducing eddy currents in a ferromagnetic drum wall using an electrical coil to heat the drum, combined with a circulation of wash liquor to evenly distribute heat, allowing for heating without free liquor and reducing energy and water usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional heating methods are used with free liquor, then heating can be performed, but energy consumption increases and water usage increases

Engineering Contradiction:
Improveheating capabilityVSAvoidenergy consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The patent replaces conventional thermal heating systems with induction heating technology. The induction heating device generates an alternating magnetic field that induces eddy currents in the ferromagnetic drum, converting electromagnetic energy directly into heat within the drum structure itself, eliminating the need for separate heating elements and free liquor reservoirs.

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

Solution Approach 2:

The drum serves multiple functions: it acts as both the rotating container for laundry and as the heating element itself. The ferromagnetic drum wall becomes the source of heat through induction, eliminating the need for separate heating systems and reducing overall system complexity while improving energy efficiency.

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

2Temperature

If conventional heating methods are used with free liquor, then heating can be performed, but water consumption increases

Engineering Contradiction:
Improveheating capabilityVSAvoidwater consumption
Core Design Contradiction:
TemperatureVSQuantity of substance

Solution Approach 1:

The induction heating system replaces the need for free liquor-based heating. By generating heat directly in the drum through electromagnetic induction, the system eliminates the requirement for additional water to be added to the drum for heating purposes, thereby reducing overall water consumption.

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

Solution Approach 2:

The patent changes the physical state and location of heat generation from external thermal sources requiring free liquor to internal electromagnetic induction within the drum structure. This parameter change allows heating to occur without altering the water content or adding additional water to the system.

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If induction heating is applied to the drum, then heating efficiency improves, but the drum structure must be made of ferromagnetic material

Engineering Contradiction:
Improveheating efficiencyVSAvoiddrum material requirements
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The ferromagnetic drum serves dual purposes: it is both the structural container for laundry and the active heating element. This eliminates the need for separate heating components and justifies the material specification, as the drum's ferromagnetic properties are directly utilized for efficient induction heating.

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

4Temperature

If wash liquor is circulated through the drum, then uniform heat distribution is achieved, but additional water is required

Engineering Contradiction:
Improveheat distribution uniformityVSAvoidwater consumption
Core Design Contradiction:
TemperatureVSQuantity of substance

Solution Approach 1:

The existing wash liquor in the drum is recirculated and utilized for heat distribution. The system leverages the water already present in the washing process, circulating it through the heated drum to distribute heat uniformly without requiring additional water input, thereby achieving thermal uniformity while maintaining water efficiency.

Inventive Principle:
Principle #25Self-service

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 approach enables efficient and uniform heating of laundry, reducing energy consumption and water usage, even with large loads, by using the drum as a heating element and minimizing the need for additional water or detergent.

Implementation Method 1

Inducing eddy currents in at least one drum wall to heat the drum

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 2

inducing eddy currents in at least one drum wall to heat the drum

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

heating via a heating element may only occur if free liquor is present

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 4

circulating washing liquor driven out of the laundry through the drum

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3246451B2Method and device for operating a washing machine
Publication Date: 2023.03.29 MIELE & CO KG
  • EP3246451B2 patent drawingFigure 1
  • EP3246451B2 patent drawingFigure 2
  • EP3246451B2 patent drawingFigure 3

AI summary

The invention relates to a method for washing laundry, a method for operating a washing machine, and a washing machine for washing laundry. The method can be carried out in connection with a washing machine (100) which has a drum (110) for receiving the laundry. The drum (110) has at least one drum wall made of a ferromagnetic material. The method includes a step of inducing eddy currents in the at least one drum wall of the drum (110) to heat the drum (110). The method further comprises a step of circulating wash liquor expelled from the laundry through the drum (110) to flood the laundry with wash liquor to saturate the laundry with wash liquor.