Auto-Dosing Detergent Rheology for Stable Washing Machine Dispensing

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Solution Overview

Problem

Automatic cleaning machines with auto-dosing capabilities experience significant detergent dosing fluctuations, leading to inconsistent cleaning performance, and existing solutions to improve precision are costly and complex to implement.

Innovation Solution

A liquid detergent with a total surfactant level of at least 25 wt% and high-shear viscosity ranging from 10 mPa·s to 500 mPa·s, which exhibits shear-thinning properties, reducing dosing fluctuations by maintaining high viscosity at low shear rates and low viscosity at high shear rates, thereby improving dosing accuracy without additional precision-improving devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If additional precision-improving devices (such as single dose chamber with sensors and controllers) are installed to reduce dosing deviations, then dosing precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvedosing precisionVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes the rheological parameters of the detergent composition itself, specifically controlling viscosity at different shear rates. By formulating the detergent to have appropriate viscosity characteristics (low viscosity at high shear rates for easy dispensing, controlled viscosity at low shear rates for dosing accuracy), the system achieves precise dosing without adding complex mechanical or electronic control devices.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the need for complex mechanical precision-dosing devices (such as sensors, controllers, and single-dose chambers) with a chemically-formulated detergent composition. The detergent's inherent rheological properties substitute for mechanical precision-control systems, achieving accurate dosing through material science rather than engineering complexity.

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

2Manufacturing precision

If additional precision-improving devices are installed to reduce dosing deviations, then dosing precision is improved, but manufacturing cost increases

Engineering Contradiction:
Improvedosing precisionVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent modifies the chemical composition parameters of the detergent, specifically the viscosity-shear rate relationship, to achieve precise dosing. This formulation approach is more cost-effective than installing expensive precision-dosing hardware, as it leverages material properties rather than requiring additional manufactured components.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a chemically-formulated detergent composition that can be easily manufactured and dispensed without requiring expensive, complex dosing equipment. The solution trades the cost of precision hardware for the cost of formulated material, which is inherently cheaper and easier to manufacture at scale.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Device complexity

If manual filling of detergent dispensing trays is performed, then no additional devices are needed, but user convenience decreases and dosing accuracy cannot be ensured

Engineering Contradiction:
Improvedevice simplicityVSAvoiduser convenience
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent enables the detergent composition to 'self-regulate' the dosing process through its inherent rheological properties. The detergent automatically provides consistent dosing without user intervention or complex device control, as the viscosity-shear rate relationship ensures proper flow and dispensing characteristics throughout the dosing process.

Inventive Principle:
Principle #25Self-service

4Productivity

If auto-dosing devices operate at high dosing rate and high shear, then productivity is improved, but dosing fluctuations increase without precision-improving devices

Engineering Contradiction:
Improvedosing rateVSAvoiddosing consistency
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent specifically engineers the detergent's viscosity-shear rate relationship to handle high-speed dosing conditions. By controlling the detergent to have low viscosity at high shear rates (high dosing rates) while maintaining appropriate viscosity at low shear rates, the system achieves both high productivity and dosing consistency simultaneously, without requiring precision-improving devices.

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

The use of this detergent composition significantly reduces dosing fluctuations and enhances cleaning performance consistency in automatic cleaning machines, improving dosing accuracy and reducing the need for additional precision devices or machine replacement.

Implementation Method 1

a high-shear viscosity ranging from about 10 mPa·s to about 500 mPa·s when measured at 20° C. at a relatively high shear rate of about 20 s−1

Methodology Applied
Scientific EffectShear thinning: Shear Thinning

Data Source

PatentUS11668043B2Method and system for reducing auto-dosing fluctuation of an automatic cleaning machine
Publication Date: 2023.06.06 PROCTER & GAMBLE CO

AI summary

A method for reducing auto-dosing fluctuation of a washing machine equipped with an automatic dosing device, by using a liquid detergent with a relatively low high-shear viscosity. A cleaning system including a washing machine equipped with an auto-dosing device, in combination with a liquid detergent characterized by a relative low high-shear viscosity.