NDIR Gas Analyzer Optopneumatic Detector for Source Ageing Correction
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Solution Overview
Problem
NDIR gas analyzers face challenges in diagnosing faults due to the ageing of the infrared radiation source and dirt deposits in the optical radiation path, particularly in single-beam devices where regular calibration with calibration gas is necessary, reducing availability for measurement.
Innovation Solution
Incorporating an optopneumatic detector in the radiation path, either between the infrared radiation source and the measuring vessel or between the measuring vessel and the detector device, filled with a gas that either matches or does not match the measuring gas component's absorption spectrum, to generate a detector signal that corrects for radiation source intensity and dirt-related changes, allowing for continuous monitoring and correction of measurement results without interrupting the measurement process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If regular calibration with calibration gas is performed to compensate for emitter ageing and window dirt, then measurement accuracy is maintained, but availability for measurement purposes is reduced
Solution Approach 1:
The patent implements preliminary action by continuously monitoring the infrared radiation intensity before actual measurements using a photodetector. This allows the system to detect emitter ageing and window dirt accumulation in advance, enabling real-time compensation without interrupting the measurement process for calibration.
Solution Approach 2:
The patent employs feedback by using the photodetector to continuously monitor the infrared radiation intensity and feeding this information back to correct measurement values. The system automatically adjusts for emitter ageing and window dirt based on the monitored radiation levels, maintaining accuracy without requiring external calibration gas interventions.
2Reliability
If a two-beam NDIR gas analyzer with zero compensation and further flow or pressure-sensitive sensor is used to monitor functionality and regulate infrared radiation source, then functionality monitoring is improved and calibration intervals can be extended, but device complexity increases
Solution Approach 1:
The patent extracts the monitoring function from the main measurement path by using a separate photodetector that only monitors the infrared radiation intensity without participating in the actual gas concentration measurements. This separation allows functionality monitoring to be added with minimal impact on the core measurement system.
Solution Approach 2:
The patent implements multi-functionality by using the photodetector to serve multiple purposes: monitoring emitter ageing, detecting window dirt accumulation, and providing data for both functionality assessment and measurement correction. This single component performs what would otherwise require multiple separate systems.
3Reliability
If optopneumatic detector is added to continuously monitor infrared radiation source for dirt and ageing, then measurement reliability is improved, but device complexity increases
Solution Approach 1:
The patent introduces an intermediary photodetector that mediates between the infrared radiation source and the measurement system. This intermediary component continuously monitors the radiation intensity and provides correction data, acting as a buffer that improves reliability without requiring direct modification of the core measurement apparatus.
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 continuous monitoring and correction of measurement results, maintaining system sensitivity and reducing the need for frequent calibration, thereby enhancing the reliability and availability of the gas analyzer.
Implementation Method 1
the absorption spectrum of the gas 16 lies outside of the spectra of the measuring gas component 5 and further transverse gases in the gas mixture 4
Implementation Method 2
at least one optopneumatic detector 15, 15' that is arranged in the radiation path of the infrared radiation source 1
Data Source
AI summary
The invention relates to a NDIR-gas analyser comprising an infrared radiation source (1), a measuring vessel (3) containing a gas mixture (4) having a measuring gas component (5) that is to be detected, and a detector device (7) that is arranged behind the measuring vessel that can detect the influence of ageing of the radiation source (1) and optionally dirt deposits in the optical radiation path without interrupting measuring. According to the invention, at least one optopneumatic detector (15) is arranged in the beam path of the radiation source (1), said detector being filled with any gas (16) when arranged between the radiation source (1) and the measuring vessel (3). The concentration of measuring gas components is lower in the detector (15) than in the measuring vessel (3) if filled with the measuring gas components, and said detector is filled with a gas when arranged between the measuring vessel (3) and the detector device (7), the absorption spectrum of the detector being outside of the spectrum of the measuring gas components (5) and other transversal gases in the gas mixture (4). The measuring signal (12) of the detector device (7) is corrected by the detector signal (21) generated by the detector (15).