Gas Concentration Measurement with Collinear Dual-Wavelength Absorption
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Solution Overview
Problem
Existing methods for determining gas species concentrations in containers are hindered by variations in total pressure and background effects, leading to inaccurate measurements.
Innovation Solution
A method using two collinear electromagnetic radiation paths with different wavelengths to determine the concentration of a first gas species, utilizing the characteristics of a second gas species to account for pressure variations and background effects, and an apparatus to implement this method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If infrared absorption spectroscopy is used to determine gas species concentration, then non-invasive and non-destructive measurement is achieved, but measurement accuracy is reduced due to pressure variations and background effects
Solution Approach 1:
A reference gas species is introduced as an intermediary element to compensate for pressure variations and background effects. The reference gas absorbs radiation at a different wavelength, and its absorption characteristics serve as a mediator to correct the measurement of the target gas species, thereby maintaining accuracy without compromising the non-invasive measurement capability
Solution Approach 2:
The method changes the measurement parameters by introducing a second wavelength corresponding to a reference gas species with different absorption characteristics. By measuring both wavelengths and analyzing their ratio, the system compensates for pressure and background effects, improving concentration determination accuracy while preserving the non-invasive approach
2Device complexity
If single wavelength infrared radiation is used to measure gas concentration, then measurement simplicity is maintained, but accuracy deteriorates under varying total pressure conditions
Solution Approach 1:
The method adds another dimension to the measurement by introducing a second wavelength (reference gas species) in addition to the first wavelength (target gas species). This dimensional expansion allows the system to separate the effects of pressure variations from concentration measurements, improving accuracy without significantly increasing operational complexity
3Reliability
If infrared radiation passes through container walls and gas to enable non-contact measurement, then destructive analysis is avoided, but background interference from external substances increases
Solution Approach 1:
The reference gas species acts as an intermediary that helps distinguish between absorption signals from the target gas species and background interference. By measuring the reference gas absorption at a different wavelength, the system can separate and compensate for background effects, maintaining non-destructive measurement capability while reducing interference from external substances
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
Accurately measures gas species concentrations under varying conditions by compensating for total pressure and background interference, enabling high-precision detection of gas species like oxygen, water vapor, and carbon dioxide.
Implementation Method 1
infrared absorption spectroscopy is a known method, which is suitable to determine the concentration of specific monitored gases species in a container
Implementation Method 2
The radiation intensity of the infrared radiation is reduced in absorption bands specific for different species of gas
Data Source
AI summary
Method of determining a concentration of a first gas species in an interior space (3′) of a container (3), wherein the method comprises the steps:—transmitting first electromagnetic radiation of a first wavelength along a first radiation path (1) across said container, wherein said first wavelength corresponds to the wavelength of an absorption line of said first gas species;—transmitting second electromagnetic radiation of a second wavelength along a second radiation path (2) across said container, wherein said second wavelength corresponds to the wavelength of an absorption line of a second gas species, wherein said second radiation path is collinear with said first radiation path in a section (4) of said first radiation path and wherein said section extends at least across said interior space of said container;—receiving transmitted first electromagnetic radiation and determining a first characteristics of the received first electromagnetic radiation;—receiving transmitted second electromagnetic radiation and determining a second characteristics of the received second electromagnetic radiation;—determining said concentration of said first gas species in function of said first characteristics and of said second characteristics. Furthermore, the invention refers to an apparatus for determining a concentration of a gas species and to a use of the method.