Washing Machine Automatic Dosing with Concentration Sensor Feedback

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Solution Overview

Problem

Laundry washing machines with automatic detergent dosing systems often use a predetermined detergent dose regardless of detergent type, leading to overdosing of concentrated or super-concentrated detergents, which affects rinsing performance, causes skin irritation, increases water and energy consumption, and raises laundry costs.

Innovation Solution

A method that uses a concentration sensor and recirculation circuit to detect detergent concentration and adjust the detergent dose during the washing cycle based on the laundry load and detergent type, ensuring the correct amount of detergent is used.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a predetermined dose of detergent is dispensed at any washing cycle, then the dosing operation is simple and fast, but the detergent concentration cannot be adapted to different detergent types leading to overdosing

Engineering Contradiction:
Improvedosing speedVSAvoiddetergent type adaptation
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent implements a feedback mechanism where a concentration sensor measures the detergent concentration in the washing liquid, and this measurement is fed back to the control unit which then adjusts the detergent dosing accordingly. This closed-loop control enables the system to adapt to different detergent types while maintaining efficient operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically changes the dosing parameter (detergent amount) based on the detected concentration parameter. By measuring the actual detergent concentration and adjusting the dosing quantity accordingly, the system adapts to different detergent types without compromising dosing speed.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If concentrated or super-concentrated detergent is used with a predetermined dose, then detergent costs are reduced, but rinsing performance deteriorates and skin irritation increases

Engineering Contradiction:
Improvedetergent amountVSAvoidskin irritation
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The concentration sensor provides real-time feedback on the detergent concentration in the washing liquid. The control unit uses this information to prevent overdosing, ensuring that the detergent amount is appropriate for the concentration level, thereby avoiding skin irritation and rinsing problems.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The dosing system transitions from a static predetermined dose to a dynamic dosing approach where the detergent amount is continuously adjusted based on the detected concentration. This dynamic adaptation ensures optimal detergent usage regardless of detergent type.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If the same predetermined detergent dose is used for all detergent types, then the dosing system is simple to operate, but detergent costs increase due to overdosing

Engineering Contradiction:
Improvedosing simplicityVSAvoiddetergent consumption
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The system performs self-adjustment by automatically detecting the detergent concentration and regulating the dosing amount without user intervention. The user simply loads the detergent container, and the system handles the adaptation to different detergent types autonomously.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces manual dosing adjustment with an automated sensor-based system. The concentration sensor and control unit substitute for manual intervention, automatically optimizing detergent usage based on detected concentration levels.

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

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 ensures optimal detergent usage, maintaining rinsing phase duration and energy consumption, reducing detergent costs, and preventing skin irritation by accurately dosing detergent based on concentration and load.

Implementation Method 1

a concentration sensor device which detects a concentration of the detergent in a liquid to be washed

Methodology Applied
Scientific EffectAbsorption Spectroscopy: Absorption Spectroscopy

Data Source

PatentEP3486358B1Method for washing laundry in a laundry washing machine with an automatic dosing device and laundry washing machine
Publication Date: 2020.09.23 ELECTROLUX APPLIANCES
  • EP3486358B1 patent drawingFigure 1
  • EP3486358B1 patent drawingFigure 2
  • EP3486358B1 patent drawingFigure 3

AI summary

The present invention relates to a method for washing laundry during a washing cycle in a laundry washing machine (1) comprising a washing drum (4); a washing tub (3) external to the washing drum (4); a water supply unit (5) to supply water (W) into the washing tub (3); an automatic dosing device (58) comprising a compartment suitable for receiving a quantity of detergent (D) sufficient for a plurality of washing cycles; a recirculation circuit (30) and a concentration sensor device (80). The method comprises the steps of: introducing a first prefixed quantity (Qld) of detergent (D) and a first prefixed quantity (Q1w) of water (W) into the washing tub (3); activating the recirculation circuit (30) for mixing the first prefixed quantity (Qld) of detergent (D) with the first prefixed quantity (Q1w) of water (W); determining the current concentration value (V) of the detergent (D); comparing the current concentration value (V) with one or more prefixed concentration levels (T1, T2) and either introducing or not introducing a second quantity (Q2d) of detergent (D) into the washing tub (3) according to the result of the comparison. The first prefixed quantity (Qld) of detergent (D) and/or the second quantity (Q2d) of detergent (D) is determined on the base of the amount of laundry load (L).