Gas Concentration Measurement Using Dynamic Absorption Coefficients
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Concentration measurement devices face inaccuracies due to variations in light source wavelength, particularly with LEDs, which affect absorbance measurements of gases, despite using correction factors and absorption coefficients, leading to insufficient error suppression.
Innovation Solution
A concentration measurement method and device that uses a reference gas with an absorption peak wavelength matching the light source's peak wavelength, combined with a bandpass filter to narrow the light spectrum, allowing for precise concentration calculations based on measured peak wavelengths and temperatures, thereby reducing measurement errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a reference gas with fixed absorption coefficient is used for concentration measurement, then the measurement process is simple, but measurement accuracy deteriorates due to light source wavelength variations
Solution Approach 1:
The patent introduces a dynamic correction mechanism that adjusts the absorption coefficient based on the actual light source wavelength. Instead of using a fixed absorption coefficient, the system measures the actual wavelength and selects or calculates the corresponding absorption coefficient from pre-stored data, making the measurement system adaptive to wavelength variations while maintaining operational simplicity.
Solution Approach 2:
The patent changes the parameter of absorption coefficient from a fixed value to a variable value that depends on the light source wavelength. By storing absorption coefficients for multiple wavelengths and selecting the appropriate one based on actual measurement conditions, the system maintains measurement accuracy without complicating the user operation.
2Measurement precision
If correction factors are applied to account for wavelength variations, then measurement accuracy improves slightly, but error suppression remains insufficient
Solution Approach 1:
The patent implements a feedback mechanism where the actual light source wavelength is measured and used to adjust the absorption coefficient. This closed-loop approach ensures that the correction is based on real measurement data rather than assumed values, significantly improving error suppression reliability.
Solution Approach 2:
The patent creates a lookup table or database that copies and stores absorption coefficients for multiple wavelengths. During measurement, the system copies the appropriate absorption coefficient from the stored data based on the actual wavelength, providing accurate corrections without complex real-time calculations.
3Adaptability or versatility
If the light source wavelength is allowed to vary within a range, then the light source design is flexible, but absorbance measurements become inaccurate
Solution Approach 1:
The patent changes the absorption coefficient parameter dynamically based on the actual wavelength. This allows the system to accommodate wavelength variations in the light source design while maintaining measurement accuracy through appropriate parameter adjustment.
Solution Approach 2:
The patent performs preliminary action by pre-storing absorption coefficients for multiple wavelengths before actual measurement. This allows the system to handle wavelength variations without requiring real-time complex calculations, maintaining both design flexibility and measurement accuracy.
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 enables accurate concentration measurement of various gases by minimizing wavelength-dependent errors, improving measurement accuracy and reducing variations in absorption coefficients.
Implementation Method 1
a light from a light source having a predetermined wavelength is made incident on a measurement cell through which a gas flows, and transmitted light passing through the measurement cell is received by a light receiving element
Implementation Method 2
absorbance is measured. Further, from the measured absorbance, the concentration of the measured gas can be determined according to Lambert-Beer's law
Data Source
AI summary
A concentration measurement method performed in a concentration measurement device including an electric unit having a light source and a photodetector, a fluid unit having a measurement cell through which a gas flows, and a processing circuit for calculating a concentration of the gas based on an intensity of a light passing through the measurement cell. The concentration measurement method includes a step of determining an absorption coefficient of the measurement gas using a reference absorption coefficient determined in association with the reference gas and a correction factor associated with the measurement gas, and a step of obtaining a concentration of the measurement gas flowing in the measurement cell using the absorption coefficient of the measurement gas. When the absorption peak wavelength of the measurement gas is longer than the peak wavelength of the light source, a reference gas having a longer absorption peak wavelength than the peak wavelength of the light source is used, and when the absorption peak wavelength of the measurement gas is shorter than the peak wavelength of the light source, a reference gas having a shorter absorption peak wavelength than the peak wavelength of the light source is used.