A method for washing laundry in a laundry washing machine and laundry washing machine implementig the method

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Solution Overview

Problem

Laundry washing machines lack an efficient method to optimize washing cycles, determine soil levels, and automatically adjust rinsing phases to ensure thorough cleaning and detergent removal, while maintaining low manufacturing costs.

Innovation Solution

Incorporating an electrical conductivity detecting device to differentiate between liquid and powder detergents and a turbidity detecting device to assess soil levels, allowing for adaptive washing and rinsing phases based on measured conductivity and turbidity thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional washing machines use fixed washing cycles, then manufacturing costs are low, but cleaning efficiency and detergent removal are insufficient

Engineering Contradiction:
Improvecleaning efficiencyVSAvoidwashing cycle control complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements feedback control by measuring electrical conductivity of the washing liquid and using this information to dynamically adjust the washing cycle. The controller continuously monitors conductivity values and compares them against thresholds to determine when to transition between washing phases, ensuring thorough cleaning while adapting to actual soil levels and detergent concentration.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The washing machine performs self-assessment of washing progress by automatically measuring conductivity and determining whether washing or rinsing phases are needed. The system autonomously decides when to switch between different washing modes and when to terminate cycles without requiring manual intervention or complex pre-programming of fixed cycles.

Inventive Principle:
Principle #25Self-service

2Reliability

If washing machines add sensor units for conductivity detection, then detergent removal and rinsing efficiency improve, but manufacturing costs increase

Engineering Contradiction:
Improvedetergent removal effectivenessVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces complex mechanical or optical sensing systems with electrical conductivity measurement. This substitution uses simple electrical sensors to detect detergent concentration and soil levels, achieving reliable detergent removal monitoring through an economically viable sensing approach that doesn't require expensive mechanical components.

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

3Reliability

If washing machines use multiple fixed rinsing phases, then detergent removal is thorough, but washing time increases

Engineering Contradiction:
Improvedetergent removal completenessVSAvoidwashing cycle duration
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent transforms fixed, static rinsing phases into dynamic, adaptive phases. The system continuously monitors electrical conductivity during rinsing and adjusts the number and duration of rinsing phases based on real-time measurements. This allows the washing machine to terminate rinsing early when detergent removal is sufficient, reducing unnecessary washing time while maintaining thorough detergent removal.

Inventive Principle:
Principle #15Dynamics

4Productivity

If washing machines implement adaptive washing cycles with sensors, then cleaning performance improves, but device complexity increases

Engineering Contradiction:
Improvewashing performanceVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent monitors and responds to changes in electrical conductivity as the key parameter indicating washing progress. By focusing on this single critical parameter and establishing threshold-based decision rules, the system achieves adaptive washing performance without implementing complex multi-parameter control algorithms, thereby maintaining relatively simple control logic.

Inventive Principle:
Principle #35Parameter changes

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 enhances the washing cycle by automatically determining the need for additional rinsing phases, improving cleaning efficiency and detergent removal, while maintaining cost-effectiveness.

Implementation Method 1

an electrical conductivity detecting device (54) that measures the conductivity of the liquid flowing therethrough

Methodology Applied
Scientific EffectElectrical conductivity: Conduction (electrical)

Implementation Method 2

a turbidity detecting device (52) that measures the turbidity of the liquid flowing therethrough

Methodology Applied
Scientific EffectTurbidity: Scattering

Data Source

PatentEP3931387B1A method for washing laundry in a laundry washing machine and laundry washing machine implementig the method
Publication Date: 2023.09.27 ELECTROLUX APPLIANCES
  • EP3931387B1 patent drawingFigure 1
  • EP3931387B1 patent drawingFigure 2
  • EP3931387B1 patent drawingFigure 3

AI summary

The invention relates a method for washing laundry in a laundry washing machine (1) comprising a washing tub (3) external to a washing drum (4) and an electrical conductivity detecting device (52). The method comprises the steps of comparing (172; 440) a first measured conductivity (Cc) with a first threshold (ΔC1; ΔC31) and comparing (430; 480; 482) a second measured conductivity (Cc) with a second threshold (ΔC11, ΔC21; ΔC21, ΔC22; ΔC32) for performing one or more actions based on the result of said first comparison step and/or said second comparison step. The value of said second threshold (ΔC11, ΔC21; ΔC21, ΔC22; ΔC32) is lower than the value of said first threshold (ΔC1; ΔC31).