Non-Contact Turbidity Sensor Using Transmitted Light

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Solution Overview

Problem

Current turbidity measurement methods in liquids are prone to errors due to varying liquid levels and interference with the light source, requiring submersion which complicates maintenance and is labor-intensive, especially in applications like storm drains and industrial processes.

Innovation Solution

A monitoring system that emits light towards the liquid surface from a distance, using a light detector to capture the intensity and spatial distribution of transmitted light, with processing circuitry determining turbidity without physical contact, allowing for easier installation, reduced maintenance, and efficient data analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a light source is submerged into the liquid for turbidity measurement, then measurement can be performed, but maintenance becomes difficult and the liquid process may be disturbed

Engineering Contradiction:
Improveturbidity measurementVSAvoidmaintenance difficulty
Core Design Contradiction:
Measurement precisionVSEase of repair

Solution Approach 1:

The patent introduces an intermediary medium (air gap) between the light source/detector and the liquid. The system measures turbidity by directing light through the liquid from above without submerging the optical components, using the liquid's surface as the measurement interface. This resolves the contradiction by enabling measurement while preventing contact between the light source and liquid, thus eliminating maintenance difficulties.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If a photodetector is placed in the liquid body for measurement, then turbidity can be measured, but the liquid process is interfered with and contamination risk increases

Engineering Contradiction:
Improveturbidity measurementVSAvoidprocess interference and contamination
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the light source and photodetector from the liquid environment and positions them above the liquid surface. The measurement is performed by directing light through the liquid column from above and detecting the transmitted or scattered light. This extraction eliminates process interference and contamination risks while maintaining measurement capability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If light source and detector are placed at specific distance from liquid surface, then measurement accuracy improves, but installation complexity increases

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidinstallation requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs dynamic adjustment mechanisms that allow the light source and detector to be positioned at optimal distances from the liquid surface during operation. The system can adapt to varying liquid levels and measurement requirements, maintaining accuracy without requiring fixed, complex installation structures. This dynamic positioning capability resolves the contradiction between precision and installation complexity.

Inventive Principle:
Principle #15Dynamics

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 solution provides accurate and efficient turbidity measurements with reduced maintenance needs and improved usability, enabling better monitoring of liquid properties in various applications, including storm drains and industrial processes, by eliminating the need for physical contact and allowing for networked communication of measurement data.

Implementation Method 1

a light source configured to emit light towards the surface of said liquid, such that at least a portion of said light is transmitted through said liquid

Methodology Applied
Scientific EffectLight transmission: Light

Implementation Method 2

a light detector configured to detect light that has been emitted from said light source and transmitted through said liquid and to generate a representation of the intensity and spatial distribution of the emitted light that has been detected

Methodology Applied
Scientific EffectLight detection: Photoelectric Effect

Data Source

PatentEP3814755B1Sensor for level and turbidity measurement
Publication Date: 2023.03.22 IVL SVENSKA MILJOINST AB
  • EP3814755B1 patent drawingFigure 1~3
  • EP3814755B1 patent drawingFigure 4a~4d
  • EP3814755B1 patent drawingFigure 5a~5d

AI summary

The present invention relates to a monitoring system for measuring and communicating properties of a liquid, wherein said monitoring system is configured to be arranged in a mounted position above and at a distance from a surface of the liquid, and wherein said monitoring system comprises: a light source configured to emit light towards the surface of said liquid, such that at least a portion of said light is transmitted through said liquid; a light detector configured to detect light that has been emitted from said light source and transmitted through said liquid and to generate a representation of the intensity and spatial distribution of the emitted light that has been detected; a processing circuitry being configured to determine the turbidity of the liquid based on said representation.