Turbidity Sensor Plausibility Check via Multi-Path Detection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing turbidity measurement methods, such as the four-beam alternating light method, are insensitive to minor disturbances and lack self-diagnosis capabilities, leading to inaccurate results due to component fluctuations and soiling, which cannot be detected in real-time.

Innovation Solution

The method involves using multiple propagation paths with different detectors to calculate additional turbidity values, allowing for plausibility checks by comparing solids concentrations and outputting error messages or repeating measurements if deviations exceed threshold values, and utilizing machine learning to adapt and diagnose faults in the measurement system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the four-beam alternating light method is used to measure turbidity, then component fluctuations and soiling are compensated to a certain extent, but the measurement system lacks self-diagnosis capabilities and remains insensitive to minor disturbances

Engineering Contradiction:
Improvecompensation for component fluctuations and soilingVSAvoidsensitivity to minor disturbances
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The measurement system is divided into multiple independent propagation paths (direct and indirect paths for multiple emitters and detectors). Each path provides independent measurement data that can be individually evaluated for plausibility, allowing the system to segment the overall measurement into verifiable components that can detect minor disturbances in specific paths.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system implements feedback by comparing measured turbidity values against expected ranges and plausibility criteria. When deviations are detected in specific propagation paths, the system provides feedback through error messages and can trigger corrective actions such as repeating measurements, thereby enabling self-diagnosis of minor disturbances.

Inventive Principle:
Principle #23Feedback

2Reliability

If multiple propagation paths are used to compensate for soiling and component fluctuations, then measurement reliability improves, but the complexity of the measurement system increases

Engineering Contradiction:
Improvecompensation for soiling and component fluctuationsVSAvoidnumber of emitters and detectors
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple emitters and detectors serve multiple functions: they simultaneously provide direct propagation path measurements for primary turbidity determination and indirect propagation path measurements for soiling compensation and self-diagnosis. This multi-functionality reduces the need for separate dedicated components for each measurement objective.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system merges the primary turbidity measurement function with the soiling compensation and self-diagnosis functions into a single integrated measurement process. The same emitters and detectors used for measuring turbidity also generate data for detecting soiling and component faults, eliminating the need for separate diagnostic hardware.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If plausibility checks and error detection are implemented, then measurement accuracy improves, but the measurement process requires additional evaluation steps

Engineering Contradiction:
Improveaccuracy of turbidity measurementVSAvoidevaluation process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system implements partial plausibility checks by evaluating only critical parameters and propagation paths rather than performing exhaustive analysis of all measurement data. Error detection focuses on the most significant deviations from expected behavior, applying evaluation effort selectively to maintain accuracy while avoiding unnecessary complexity.

Inventive Principle:
Principle #16Partial or excessive action

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 enhances the accuracy of turbidity measurements by detecting interference and component faults, ensuring more reliable results and enabling real-time plausibility checks and self-diagnosis of the turbidity sensor.

Implementation Method 1

A light-emitting diode is used as an emitter to generate a measuring light beam in a suitable wavelength range

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

a photodiode can be used as a detector, which generates a detector signal, for example a photocurrent or a photovoltage, from the scattered light received

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 3

measuring the intensity of light scattered by the dispersed particles (nephelometry)

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP2260290B1Method and apparatus for measuring turbidity
Publication Date: 2021.11.03 ENDRESS HAUSER CONDUCTA GMBH CO KG
  • EP2260290B1 patent drawingFigure 1~2
  • EP2260290B1 patent drawingFigure 3a~3b
  • EP2260290B1 patent drawingFigure 4a~4b

AI summary

In a method for measuring the turbidity in a test medium by means of a turbidity sensor comprising at least one first and a second emitter and at least one first and a second detector, the first and the second emitter are successively excited in order to generate a light signal that is directed into the test medium. The respective light signal reaches the first detector on a first path of propagation through the test medium and is converted into a first detector signal by said first detector while reaching the second detector on a second path of propagation through the test medium and being converted into a second detector signal by said second detector. A turbidity value is determined using the first and the second detector signal. An additional detector signal is determined by means of at least one additional detector which the light signal reaches on another path of propagation, and the plausibility of the turbidity value is verified on the basis of the additional detector signal.