Gas Analysis Device Dynamic Detection Method Switching
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Solution Overview
Problem
Existing gas analysis devices using laser absorption spectroscopy face limitations in measuring gas concentrations over a wide dynamic range, particularly experiencing signal saturation at high concentrations and requiring calibration with standard gases.
Innovation Solution
A gas analysis device that switches between harmonic synchronous detection and direct absorption methods based on gas concentration, using modulation switching means to select appropriate detection methods for accurate and continuous measurement across varying concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If harmonic synchronous detection method is used to measure gas concentration, then measurement sensitivity is improved, but measurement range becomes limited due to signal saturation at high concentrations
Solution Approach 1:
The patent implements dynamic switching between two detection methods (harmonic synchronous detection and direct absorption method) based on the measured gas concentration level. The system automatically selects the appropriate method to maintain optimal performance across different concentration ranges, resolving the contradiction between sensitivity and measurement range.
Solution Approach 2:
The patent changes the detection parameter by switching between two different detection methods. At low concentrations, harmonic synchronous detection is used for high sensitivity, while at high concentrations, direct absorption method is used to avoid signal saturation, thus expanding the overall measurement range while maintaining precision.
2Adaptability or versatility
If direct absorption method is used to measure gas concentration, then measurement range is extended, but measurement sensitivity is reduced
Solution Approach 1:
The system dynamically selects the detection method based on concentration levels. Direct absorption method is employed for high concentration measurements where it provides adequate range without saturation, while harmonic synchronous detection is activated for low concentration measurements to maintain high sensitivity.
Solution Approach 2:
The detection parameter is changed by switching methods: direct absorption for high concentrations (extended range) and harmonic synchronous detection for low concentrations (high sensitivity). This parameter change strategy resolves the contradiction between range and sensitivity.
3Measurement precision
If harmonic synchronous detection is used for continuous concentration monitoring, then accuracy is maintained at low concentrations, but signal saturation occurs at high concentrations
Solution Approach 1:
The patent implements a dynamic measurement system that continuously monitors gas concentration and automatically switches between detection methods to maintain both accuracy and reliability across the full concentration range. This prevents signal saturation while preserving detection accuracy.
Solution Approach 2:
The detection parameter is dynamically changed based on concentration levels. Harmonic synchronous detection parameters are used for low concentrations to ensure accuracy, while direct absorption parameters are used for high concentrations to prevent saturation and maintain reliability.
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
Enables real-time measurement of gas concentrations over a wide dynamic range without signal saturation, reducing the need for calibration with standard gases and improving measurement accuracy and efficiency.
Implementation Method 1
a gas analysis device that uses the absorption of laser light to measure the concentration of a specific gas in a gas to be measured
Implementation Method 2
laser light emitted from the laser irradiation unit is detected by the light reception unit after passing through the gas to be measured in the sample cell
Implementation Method 3
Performing harmonic detection requires modulation of the frequency of light that is irradiated onto the gas to be measured. Letting 'a' represent the modulation amplitude of the sine wave signal for frequency modulation
Implementation Method 4
a first measurement means for synchronously detecting the detection signal from the light reception unit using a frequency that is an integer-multiple of the frequency and calculating the concentration of a specific gas based on the detection result if modulation is set by the modulation switching means
Data Source
AI summary
If the specific gas concentration is relatively high, controller sets 0 as the modulation amplitude in a modulation amplitude controlling voltage generator for frequency modulation of laser light, controls a switching unit to select the output of a second ADC, and causes a computation unit to compute according to the direct absorption detection method to calculate the water molecule volume concentration. If the specific gas concentration is relatively low, the modulation amplitude is set to A, not 0, controls switching unit to select the output of a first ADC, which digitizes a synchronized detection signal, and causes the computation unit to compute according to the harmonic synchronous detection method to calculate the water molecule volume concentration. The concentration calculated using either of the methods is compared against a threshold value, and if decided that an accurate result cannot be obtained, the method is switched as the measurements are continuously executed.