Optical Absorption Measurement for Oil-in-Water Concentration
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Solution Overview
Problem
Existing systems for measuring oil-in-water concentrations using fluorescence are inaccurate beyond 1,000 parts per million, limiting their effectiveness in higher concentration ranges and requiring modifications to extend measurement accuracy and stability.
Innovation Solution
The apparatus employs a single channel for transmitting and receiving excitation and fluorescent signals using optical fibers, a laser as the excitation source, and a spectrometer as the detector, with a measurement chamber design that includes a measurement window and optical block with beam splitters and an attenuator to maintain light stability and compensate for variations in light output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional fluorometer is used to measure oil concentration, then measurements are accurate up to 1,000 ppm, but measurements become inaccurate beyond this concentration
Solution Approach 1:
The patent changes the measurement parameter from fluorescence intensity to light absorption intensity. By measuring how much light is absorbed by the oil-water mixture rather than relying on fluorescence emission, the system can accurately measure concentrations from 100 ppm to 100,000 ppm, extending the measurable range beyond the 1,000 ppm limit of conventional fluorometers.
2Measurement precision
If a light source is used for absorption measurement, then material concentration can be determined, but inaccuracies occur due to changes in light source output
Solution Approach 1:
The patent incorporates a feedback mechanism where the system continuously monitors the actual light output and automatically adjusts the measurement calculations to compensate for variations. The microprocessor compares the detected light intensity against reference values and corrects for light source drift, ensuring reliable measurements even as the light source aging or environmental conditions change.
Solution Approach 2:
The system performs self-calibration by using the known properties of the measurement chamber and reference standards to automatically compensate for light source variations. The apparatus self-corrects for light output changes without requiring manual intervention, maintaining measurement reliability over time.
3Device complexity
If a single channel is used for both excitation signal transmission and fluorescent signal reception, then device complexity is reduced, but signal separation becomes more difficult
Solution Approach 1:
The patent exploits the different wavelengths (colors) of light for excitation and absorption measurement. By using a broadband light source and measuring absorption at specific wavelengths that differ from the excitation wavelength, the system can distinguish between the excitation light and the absorbed light even through a single channel, eliminating the need for complex signal separation.
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 significantly increases the accuracy of oil-in-water measurements from 1,000 ppm to 100,000 ppm, providing a stable and precise determination of oil concentrations irrespective of changes in light source output, and can be adapted for measuring other materials in liquids through absorption techniques.
Implementation Method 1
measurement of material in a liquid through absorption of light
Implementation Method 2
an optical attenuator to adjust the intensity of a transmitted signal from the light source to a level similar to that of an absorbed light signal from the target region
Data Source
AI summary
The method and apparatus as shown in the present invention is to measure the absorption of light by material contained in a liquid. A transmitted signal is sent through a measurement window to a measurement chamber to a target point just inside the measurement window. The reflected signal indicates the amount of light absorbed by a material in the measurement chamber which allows for the amount of materials in a liquid to be determined. Adjustments are made through an optical block and a light control molecule to correct for variations in light intensity.