Process Gas Analyzer Oxygen Interference Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing process gas analyzers face challenges in accurately measuring oxygen content in process gas mixtures due to the influence of atmospheric oxygen within the measuring heads, which requires costly oxygen-free gas flushing or additional optical components to compensate for interference.
Innovation Solution
Incorporating a temperature sensor in each measuring head to record and store ambient reference spectra at different temperatures, allowing the evaluation device to subtract the oxygen absorption from the detected absorption spectrum, thereby calculating the oxygen concentration without the need for oxygen-free gas flushing or additional optical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If oxygen-free gas flushing is used to prevent atmospheric oxygen interference, then measurement accuracy is improved, but operational costs increase due to consumption of expensive flushing gas
Solution Approach 1:
The patent extracts and removes the atmospheric oxygen absorption component from the measured spectrum through mathematical subtraction. By recording reference spectra without process gas and subtracting them from measurement spectra, the harmful atmospheric oxygen interference is separated and eliminated, allowing accurate measurement without oxygen-free flushing gas.
Solution Approach 2:
The patent creates a copy of the atmospheric oxygen absorption spectrum through reference measurements and uses this copied spectral information to compensate for and remove the interference in actual measurements. The reference spectra serve as a template that is subtracted from measurement spectra to eliminate the atmospheric oxygen component.
2Measurement precision
If additional optical components are added to compensate for atmospheric oxygen interference, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent replaces physical/optical compensation methods with a mathematical/software-based solution. Instead of adding optical components like reference cells or beam splitters, the system uses computational subtraction of reference spectra to remove atmospheric oxygen interference, thereby maintaining measurement accuracy while avoiding increased device complexity.
3Measurement precision
If measuring heads are sealed to prevent ambient air ingress, then measurement accuracy is improved, but device complexity and cost increase due to additional sealing and flushing systems
Solution Approach 1:
The patent enables the measurement system to compensate for atmospheric oxygen interference using its own measurement capabilities. By recording reference spectra and performing mathematical subtraction, the system serves itself to remove the interference without requiring external sealing systems or additional flushing infrastructure.
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 method effectively compensates for the influence of atmospheric oxygen, improving measurement accuracy and reducing operational costs by eliminating the need for oxygen-free gas flushing and additional optical components, while accounting for temperature variations in the measuring heads.
Implementation Method 1
In laser absorption spectroscopy, a measurement gas mixture is irradiated with light from a wavelength-tunable laser diode and the concentration of a gas component of interest in the measurement gas mixture is determined based on the reduction in light intensity caused by the absorption of the light at the point of a selected absorption line of the gas component
Implementation Method 2
a temperature sensor is arranged in at least one of the two measuring heads, which is designed to record the current temperature when measuring the absorption spectrum
Data Source
Figure 1~2
Figure 3~4
AI summary
A process gas analyzer contains a wavelength-tunable laser diode (7) and a detector (8) in two separate measuring heads (5, 6), which are mounted on diametrically opposite sides of a system component (1) containing a process gas (2). To compensate for the influence of atmospheric oxygen in the measuring heads (5, 6) on the measurement of the oxygen content in the process gas mixture (2), a temperature sensor (23, 24) is arranged in at least one of the two measuring heads (5, 6). Ambient reference spectra (27, 272f) of the ambient air contained in the two measuring heads (5, 6), recorded at different temperatures and without the process gas mixture (2), are stored in a memory (26) of an evaluation unit (19).The evaluation unit (19) is further configured to select one of the stored ambient reference spectra (272f) depending on the current temperature detected by the temperature sensor (23, 24) or to calculate it from two stored ambient reference spectra (272f) and to subtract it from the currently detected absorption spectrum (182f) of the process gas mixture (2) and to determine the oxygen concentration in the process gas mixture (2) from the difference spectrum (302f).