Dishwasher Turbidity Sensor Positioning to Prevent Soil Adherence

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Solution Overview

Problem

Conventional dishwashers face challenges in maintaining precise and stable turbidity measurements over time due to soil adherence on turbidity sensors in the drain path, leading to decreased light transmittance and inaccurate readings.

Innovation Solution

Positioning the turbidity sensor higher than the remaining water level in the drain path prevents soil adherence, keeping the sensor clean and allowing for precise and stable turbidity sensing throughout the washing cycle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the turbidity sensor is positioned in the drain path below the wash tub, then the sensor can sense the turbidity of washing water during the washing cycle, but soil adheres to the inside of the piping where the sensor is placed, decreasing light transmittance and lowering measurement accuracy over time

Engineering Contradiction:
Improveturbidity measurement accuracyVSAvoidlong-term measurement stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent extracts the turbidity sensor from the drain path piping where it would be exposed to soil-containing water. Instead, the sensor is positioned in a sensor chamber that receives water from the drain path via a separate inlet, allowing the sensor to measure turbidity without being exposed to soil that would adhere to the piping.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary sensor chamber that acts as a mediator between the drain path and the turbidity sensor. Water from the drain path is directed into this chamber through an inlet, and the sensor measures turbidity in this intermediate space rather than directly in the drain path piping, preventing soil adherence to the sensor.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the turbidity sensor is placed in the circulation path of washing water, then the sensor can monitor turbidity during washing, but water remains in the piping after draining ends, causing soil to adhere to the sensor and reduce light transmittance

Engineering Contradiction:
Improveturbidity sensing capabilityVSAvoidsoil adherence to sensor
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the sensor from the main drain path where water remains after draining. The sensor is positioned in a separate sensor chamber that is filled with water during washing but is positioned higher than the final water level after draining, ensuring the sensor is not exposed to remaining water and soil.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the spatial dimension by positioning the sensor vertically higher than the maximum level of remaining water after draining. This vertical positioning ensures that when draining ends, the sensor is above the water line and not exposed to soil-containing remaining water, preventing soil adherence.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 configuration ensures accurate turbidity measurements over a long period by preventing soil from adhering to the sensor, allowing the dishwasher to effectively determine contamination levels and adjust washing cycles accordingly.

Implementation Method 1

a transmitting light sensor is used composed of a light-emitting unit and light-receiving unit

Methodology Applied
Scientific EffectLight transmittance: Light

Data Source

PatentEP2540207B1Dish washing machine
Publication Date: 2019.12.04 PANASONIC HOLDINGS CORP
  • EP2540207B1 patent drawingFigure 1
  • EP2540207B1 patent drawingFigure 2~3
  • EP2540207B1 patent drawingFigure 4~5

AI summary

A turbidity sensor for sensing information related to the turbidity of washing water is placed in a position higher than the level of the washing water remaining in the drain path when draining of the dishwasher ends. Accordingly, water does not remain inside the piping of the drain path where the turbidity sensor is placed to keep the inside clean. This allows the dishwasher to sense the turbidity of washing water precisely and stably over a long period while washing objects to be washed appropriately according to the level of contamination of the objects.