Rinse Greywater Reuse With Fabric Softener Detection in Washing Machines

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Solution Overview

Problem

The reuse of grey water from a washing machine's rinse cycle is hindered by the presence of cationic surfactants from fabric softener, which can reduce cleaning effectiveness and form unwanted precipitates when mixed with anionic surfactants from detergents, potentially causing residue on washed items and machine components.

Innovation Solution

A washing machine system that captures effluent from the rinse cycle and determines the presence of fabric softener, allowing its reuse only in subsequent rinse cycles to avoid undesirable interactions with detergent surfactants, using sensors and processing devices to manage the reuse of grey water effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If fabric softener is added during the rinse cycle, then softening and static control of articles is improved, but cationic surfactants remain in the effluent and cause harmful interactions when grey water is reused in subsequent wash cycles

Engineering Contradiction:

Improvefabric softening effectVSAvoidprecipitate formation and residue on articles

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent segments the rinse cycle into multiple phases, adding fabric softener only in later phases rather than the first rinse. This temporal segmentation allows initial rinsing to occur with clean water, preventing surfactant interactions, while still providing fabric softening benefits in subsequent phases. The effluent from early rinse phases can then be safely reused without containing harmful cationic surfactants.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system performs preliminary analysis of the effluent to detect the presence of fabric softener surfactants before reusing the grey water. This preliminary detection action allows the control system to make informed decisions about whether to reuse the effluent or discard it, preventing harmful interactions while maximizing water reuse opportunities.

Inventive Principle:

Principle #10Preliminary action

2Loss of substance

If grey water from the rinse cycle is reused in the washing machine, then water conservation is improved, but cleaning effectiveness is reduced due to surfactant interactions

Engineering Contradiction:

Improvewater consumptionVSAvoidcleaning effectiveness

Core Design Contradiction:

Loss of substanceVSReliability

Solution Approach 1:

The patent implements a feedback control system that continuously monitors the effluent for the presence of fabric softener surfactants. Based on this feedback, the system dynamically adjusts whether to reuse the grey water or discard it. This feedback mechanism ensures that water reuse decisions are made only when safe, maintaining cleaning effectiveness while maximizing water conservation benefits.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes the operational parameter of effluent reuse based on detected surfactant concentrations. When fabric softener is detected above certain thresholds, the system switches from reuse mode to discard mode. This parameter-based control allows flexible adaptation to different washing conditions, maintaining cleaning effectiveness while optimizing water conservation.

Inventive Principle:

Principle #35Parameter changes

3Loss of substance

If a washing machine system is implemented to detect fabric softener and manage grey water reuse, then water conservation is improved, but device complexity increases due to sensors and control systems

Engineering Contradiction:

Improvewater consumptionVSAvoidsensor and control system complexity

Core Design Contradiction:

Loss of substanceVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical analysis systems with simpler optical or electrical sensors that can detect surfactant presence through light absorption or electrical properties. This substitution maintains the water conservation benefits while significantly reducing device complexity and cost compared to traditional mechanical analysis methods.

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

Enables the safe and effective reuse of grey water from rinse cycles, preventing adverse interactions with laundry detergents and maintaining cleaning effectiveness while minimizing residue formation on washed items and machine components.

Implementation Method 1

A sensor may be present in the washing machine that detects whether fabric softener is present in the effluent from the rinse cycle

Methodology Applied

Scientific EffectOptical absorption: Absorption (EM radiation)

Data Source

PatentUS9334600B2Fabric softener sensing and reuse of grey water from the rinse cycle of a washing machine

Publication Date: 2016.05.10 HAIER US APPLIANCE SOLUTIONS INC

AI summary

The capture and reuse of the effluent, or grey water, from the rinse cycle of a washing machine appliance is provided. A determination is made regarding whether fabric softener is present in the effluent. If fabric softener is present, then the effluent can be reused during a rinse cycle of the washing machine so as to avoid undesirable interaction between the fabric softener in the effluent and the detergent of a rinse cycle.