Nephelometric Turbidimeter Contamination Detection via Movable Diffuser
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Solution Overview
Problem
Nephelometric turbidimeters face challenges in reliably detecting contamination within the sample cuvette, such as fouling or scratches, which can lead to non-plausible measurement results due to strong inhomogeneities and high technical effort in existing systems.
Innovation Solution
A method and device for a nephelometric turbidimeter that includes a switchable diffuser and a diffuser actuator to change the light beam from axial parallel to diffuse, allowing for a contamination test by comparing measured light intensity with a reference, generating a contamination signal if the difference exceeds a threshold, and incorporating a cleaning device for mechanical cuvette cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two separate light sources and two separate light detectors are used to provide different turbidity measurements under different scattering angles and penetration distances, then measurement reliability is improved, but device complexity increases
Solution Approach 1:
The patent employs a movable diffuser that can dynamically change position between a measurement position (where it is removed from the light path) and a contamination test position (where it is inserted into the light path). This dynamic reconfiguration allows a single light source and detector system to perform multiple functions, reducing device complexity while maintaining measurement reliability through the ability to switch between measurement mode and contamination detection mode.
2Reliability
If a diffuser is inserted into the light path to generate diffuse test light for contamination testing, then contamination detection capability is improved, but measurement time increases due to additional testing steps
Solution Approach 1:
The patent implements periodic contamination testing by automatically inserting the diffuser into the light path at predetermined intervals or before/after measurements. This periodic action allows the system to maintain high measurement speed for routine turbidity measurements while periodically performing contamination detection to ensure ongoing measurement accuracy, thus balancing contamination detection capability with measurement time efficiency.
3Measurement precision
If a cleaning device is added to mechanically clean the cuvette, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent incorporates an automated cleaning device that can be triggered by the control unit based on contamination test results or measurement quality indicators. The cleaning mechanism uses simple mechanical components (such as a wiper or spray system) that are integrated into the existing cuvette holder structure. This self-service approach maintains high measurement accuracy by automatically removing contaminants while minimizing additional device complexity through the use of straightforward cleaning mechanisms and automated control.
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 simplifies contamination detection, ensures reliable measurement plausibility, and maintains cuvette cleanliness, reducing the impact of fouling and scratches on measurement accuracy.
Implementation Method 1
A light detector detects the amount of light scattered by the suspended solid particles at an angle of at least 30° to the light beam axis
Implementation Method 2
the diffuser body is arranged between the measurement light source and the sample cuvette so that the diffuser body interferes with the axial parallel light beam and generates a diffuse test light entering the sample cuvette
Data Source
AI summary
A method for detecting a contamination of a cuvette of a turbidimeter. The turbidimeter includes a light source which emits a light beam directed to a cuvette, a scattering light detector, and a diffuser with a body and an actuator. The actuator moves the body between a parking position and a test position where the body is between the measurement light source and the cuvette, thereby interferes with the light beam, and generates a diffuse test light entering the cuvette. The method includes activating the actuator to move the body from the parking position into the test position, activating the light source, measuring a test light intensity received by the scattering light detector, comparing the test light intensity measured with a reference light intensity, and generating a contamination signal if a difference between a reference light intensity and the test light intensity measured exceeds a first threshold value.