Multi-Path Infrared Gas Sensing for Wide Concentration Ranges
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Solution Overview
Problem
Existing gas measurement technologies struggle with accurately measuring a wide range of gas concentrations, particularly in fluid environments, and are limited in their ability to distinguish between multiple gases in a mixture, especially when concentrations vary significantly.
Innovation Solution
The apparatus employs multiple optical paths of different lengths within an enclosed space, combined with infrared radiation sources and detectors, to measure gas concentrations by analyzing infrared radiation absorption at specific wavelengths, allowing for the detection of multiple gases and extending the measurable concentration range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single optical path is used for gas measurement, then the device complexity is reduced, but the measurement precision and concentration range are limited
Solution Approach 1:
The single optical path is segmented into multiple separate optical paths, each with a specific length optimized for measuring different gas concentration ranges. This allows the system to maintain high measurement precision across a broad concentration spectrum while keeping each individual path simple and manageable.
Solution Approach 2:
The patent introduces a new dimension of path length variation to the optical measurement system. By creating optical paths of different lengths (e.g., first optical path with length L1, second optical path with length L2), the system gains the ability to measure both high and low gas concentrations simultaneously, resolving the contradiction between measurement precision and device complexity.
2Adaptability or versatility
If multiple optical paths of different lengths are used, then the measurable concentration range is extended, but the device complexity increases
Solution Approach 1:
Each optical path is designed to serve multiple functions: measuring different gas concentrations, detecting different gases with distinct absorption wavelengths, and providing reference measurements. The system achieves versatility in concentration range adaptability while maintaining relatively simple individual path structures that can be implemented using standard optical components.
3Adaptability or versatility
If a single detector measures all wavelengths, then the device complexity is reduced, but the ability to distinguish multiple gases is compromised
Solution Approach 1:
The detection system is segmented into multiple detectors, each specialized for measuring infrared radiation at specific wavelengths corresponding to different gases. This segmentation allows the system to distinguish between multiple gases (e.g., methane, carbon dioxide, water vapor) while keeping each detector's function simple and focused on a specific wavelength range.
Solution Approach 2:
Each detector is assigned a specific local quality of wavelength sensitivity, optimized for detecting particular gases. The first detector measures at a first wavelength absorbed by a first gas, while the second detector measures at a second wavelength absorbed by a second gas, enabling selective gas detection without requiring complex spectral analysis capabilities in each detector.
4Measurement precision
If the optical path length is increased, then the detection sensitivity for low concentration gases is improved, but the measurement time and energy consumption increase
Solution Approach 1:
The measurement task is segmented across multiple optical paths of different lengths. Shorter paths are used for high concentration measurements (reducing measurement time), while longer paths are used for low concentration measurements (increasing sensitivity). This segmentation allows the system to optimize both measurement precision and time efficiency without compromising either aspect.
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 precise measurement of gas concentrations across a broader range and in mixtures with varying gas concentrations, facilitating applications in leak detection, hydrocarbon analysis, and environmental monitoring.
Implementation Method 1
at least one inlet to the internal space comprising a gas-permeable membrane separating the internal space from surrounding fluid while allowing gases to diffuse from the surrounding fluid into the internal space
Implementation Method 2
at least one infrared radiation source to send infrared radiation into the internal space, at least one infrared radiation detector with connected circuitry to receive and measure the intensity of infrared radiation from the at least one source
Data Source
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AI summary
The concentration of one or more gases in a surrounding fluid is measured using apparatus having a gas-permeable membrane separating an enclosed internal space within the apparatus from the surrounding fluid while allowing gases to diffuse from the surrounding fluid into the internal space. One or more sources sends infrared radiation along optical paths to one or more infrared detectors measuring intensity of radiation after absorption by gas(es) in the internal space and concentrations are determined from measured absorptions. The apparatus has more than one optical path through the internal space, enabling measurements of concentration over a greater range or enabling measurements of more than one gas present in very different concentrations or having very different infrared absorptivities.