Self-Calibrating Optical Turbidity Measurement With Movable Standard
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Solution Overview
Problem
Existing turbidity measuring apparatuses require regular calibration using Formazine, which is unstable and affected by stirring rates, and often necessitate on-site manual calibration, leading to inefficiencies and potential measurement errors.
Innovation Solution
A self-calibrating optical turbidity measuring apparatus that automatically adjusts calibration using a movable optical standard, allowing for remote calibration and reducing contact between the standard and the medium, thereby minimizing fouling and sensor drift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Formazine is used as a calibration standard, then calibration can be performed, but the standard is unstable and may drop out of solution quickly
Solution Approach 1:
The patent employs disposable single-use calibration cuvettes containing pre-filled Formazine standards. Each cuvette is designed for one-time use only, eliminating the need to maintain stable Formazine solutions in the instrument. The cuvette is discarded after calibration, ensuring fresh, stable calibration material for each use while avoiding the degradation issues of reusable Formazine solutions.
Solution Approach 2:
The calibration standard (Formazine solution) is prepared and sealed in advance within the disposable cuvette before use. This preliminary preparation allows the calibration material to be stored in optimal conditions until use, and the cuvette is designed to maintain solution stability until the moment of calibration, preventing premature degradation or precipitation.
2Measurement precision
If manual calibration is performed on-site, then calibration can be adjusted, but it requires regular manual intervention and leads to inefficiencies
Solution Approach 1:
The system enables self-calibration by automatically detecting the calibration cuvette type and concentration, then performing the calibration process without requiring manual intervention. The instrument reads the cuvette's embedded identification (e.g., RFID tag, barcode, or optical identifier) and automatically configures the appropriate calibration parameters, eliminating the need for operators to manually perform calibration procedures.
Solution Approach 2:
The patent replaces manual mechanical calibration operations with automated optical and electronic systems. The instrument uses optical sensors, RFID readers, or barcode scanners to identify the calibration cuvette, and then automatically executes the calibration algorithm, substituting human manual operations with automated electromechanical and optical systems to improve precision and reduce time loss.
3Reliability
If the optical standard is in constant contact with the medium, then calibration is continuous, but fouling increases and requires more maintenance
Solution Approach 1:
The patent extracts the optical calibration standard from the measurement path, using a separate disposable cuvette that is not in continuous contact with the process medium. The calibration cuvette contains its own isolated Formazine solution, physically separated from the sample being measured. This extraction eliminates cross-contamination and fouling of the calibration standard by the process medium, maintaining measurement reliability without generating harmful fouling effects.
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
Enhances measurement reliability and precision by reducing the need for manual calibration, minimizing fouling, and enabling frequent self-calibrations, thus improving handling and reducing maintenance intervals.
Implementation Method 1
Turbidity is a measure of cloudiness, haziness, absorbance, or amount of scattering of an optical beam applied through or across a liquid medium
Implementation Method 2
Turbidity is a measure of cloudiness, haziness, absorbance, or amount of scattering of an optical beam applied through or across a liquid medium
Data Source
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AI summary
A self-calibrating optical turbidity measuring apparatus (10), comprising: a housing (20) comprising a cavity (25) with an inner wall (26), wherein the inner wall (26) comprises an essentially straight section (22) in the area of a first end (21 ) of the cavity (25), and an opening for the medium (28), an optical standard (40), which is moveable between a first section (23) and a second section (24) within the essentially straight section (22), and a light source (30) and a light sensor (35), arranged at the first section (23) and configured to measure the turbidity of the medium, when the optical standard (40) is at the second section (24), and configured to measure the turbidity of the optical standard (40) and to determine, as a function of the measured turbidity, a calibration coefficient for performing a self-calibration, when the optical standard (40) is at the first section (23).