Washing Machine Impedance Sensor Rinsing for Water and Time Reduction

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Solution Overview

Problem

Current washing machine rinsing phases are inefficient due to inadequate consideration of detergent concentration, leading to prolonged rinsing times and excessive water usage, as they rely on empirically determined cycles rather than real-time detergent measurement.

Innovation Solution

The method employs an impedance sensor to track detergent concentration over time, adjusting the rinsing phase by configuring the number of rinsing steps and water quantity based on measured impedance signals, allowing for precise control of the rinsing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If time-controlled rinse cycles are used, then the rinse process is simple to operate, but the rinse duration cannot be optimized based on actual detergent concentration

Engineering Contradiction:
Improverinse cycle controlVSAvoidrinse cycle efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent implements feedback control by continuously measuring detergent concentration in rinse water using an impedance sensor and adjusting the rinse cycle duration and water quantity accordingly. The control device receives impedance signals, converts them to detergent concentration values, and uses this information to dynamically modify the rinse process, ensuring it ends precisely when detergent removal is complete rather than following a fixed time schedule.

Inventive Principle:
Principle #23Feedback

2Ease of manufacture

If empirically determined rinse cycles are used, then the process is easy to implement, but excessive water and energy are consumed

Engineering Contradiction:
Improverinse cycle implementationVSAvoidwater consumption
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

The system uses real-time feedback from impedance measurements to determine exactly when detergent has been sufficiently removed from laundry. This allows the rinse cycle to terminate precisely at the optimal point rather than continuing for a fixed duration, significantly reducing water consumption and energy usage associated with heating and pumping excess rinse water.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces empirical time-based control with electrochemical impedance measurement and electronic control. The impedance sensor detects detergent concentration through electrical measurements, and the control device processes this data to automatically adjust rinse parameters, substituting mechanical/time-based routines with intelligent sensor-driven control.

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

3Device complexity

If fixed number of rinse cycles are used, then the program is simple to control, but detergent may not be completely removed or unnecessary rinsing occurs

Engineering Contradiction:
Improverinse program structureVSAvoiddetergent removal completeness
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The control device continuously monitors detergent concentration through impedance measurements during each rinse cycle and uses this feedback to determine when to terminate rinsing. This ensures detergent is completely removed when present, while avoiding unnecessary continuation when removal is complete, adapting the rinse program dynamically rather than following a fixed predetermined sequence.

Inventive Principle:
Principle #23Feedback

4Reliability

If rinse cycles continue beyond equalization completion, then thorough rinsing is achieved, but time and energy are wasted

Engineering Contradiction:
Improverinse completenessVSAvoidrinse cycle duration
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The impedance sensor provides real-time feedback on detergent concentration, allowing the control device to detect when equalization between rinse water and detergent on laundry is complete. The system terminates the rinse cycle at this precise moment, ensuring thorough rinsing without the time and energy waste of continuing beyond completion.

Inventive Principle:
Principle #23Feedback

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 more efficient and water-saving rinsing, optimizing rinsing time and water usage while ensuring complete detergent removal, reducing pollution and energy consumption.

Implementation Method 1

an impedance sensor (also referred to as an electrochemical impedance sensor) in the container for measuring an impedance signal as a function of the composition of an aqueous liquid in the container

Methodology Applied
Scientific EffectElectrical Impedance: Electrical Resistance

Implementation Method 2

These surfactants reduce the surface tension of the water in the resulting aqueous solution (washing solution)

Methodology Applied
Scientific EffectSurface Tension Reduction: Surface Tension

Data Source

PatentEP3268530B1Method for operating a washing machine having an improved rinsing phase and washing machine suitable therefor
Publication Date: 2023.04.19 BSH HAUSGERATE GMBH
  • EP3268530B1 patent drawingFigure 1

AI summary

The invention relates to a method for operating a washing machine 1, comprising a container 2, a drum 3 for receiving items of laundry 4, a drive motor 5 for the drum 3, an impedance sensor 9 in the container 2 for measuring an impedance signal as a function of a composition of an aqueous liquid 7 in the container 2, and a control device 8, wherein, subsequent to a washing phase, the detergent concentration cten in the rinsing liquid 7 is monitored during the rinsing phase by the impedance sensor 9, and wherein the temporal increase in the detergent concentration cten is evaluated with regard to the further configuration of the rinsing phase. The invention further relates to a washing machine 1 suitable for carrying out the method.