Combustion-Zone Chemical Sensing with MIR Reflective Optics
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Solution Overview
Problem
Conventional TDLAS systems face challenges in operating at mid-infrared wavelengths due to attenuated transmission in fiber optics and chromatic aberration in lenses, limiting signal-to-noise ratio and detection sensitivity, especially for molecules with strong absorption features in the mid-infrared region.
Innovation Solution
A single optical head system with off-axis parabolic mirrors and a reflector, such as a retroreflector, is used to collimate and focus mid-infrared electromagnetic energy within a combustion zone, reducing fiber length and maintaining sufficient light intensity for detection, while accommodating a broad bandwidth of electromagnetic energy including mid-infrared, near-infrared, and visible light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional TDLAS systems use fiber optic cables to transmit mid-infrared light, then the system can maintain distances between electronics and combustion chamber, but the fiber optic transmission is attenuated reducing signal-to-noise ratio
Solution Approach 1:
The patent introduces a reflective optics system with mirrors and reflectors as intermediaries to redirect and focus mid-infrared light. Instead of relying solely on fiber optic transmission through the combustion chamber, the reflective optics act as mediators to guide the light path, reduce transmission distance through attenuating media, and maintain sufficient signal intensity for detection.
2Measurement precision
If conventional TDLAS systems use lenses to focus light, then the system can concentrate electromagnetic energy, but chromatic aberration occurs limiting detection sensitivity
Solution Approach 1:
The patent replaces the conventional lens-based focusing system with a reflective optics system using mirrors and reflectors. This substitution eliminates chromatic aberration because reflection does not suffer from the same wavelength-dependent focal length issues that lenses do. The reflective optics can focus mid-infrared light without the harmful chromatic effects that limit detection sensitivity.
3Reliability
If conventional TDLAS systems use separate pitch head and catch head, then the system can maintain distances from combustion zone, but the device complexity increases
Solution Approach 1:
The patent merges the pitch head and catch head functions into a single integrated optical head assembly. This combined structure maintains the ability to position components at safe distances from the combustion zone while reducing the overall system complexity by eliminating the need for separate pitch and catch head assemblies and their associated fiber optic connections.
4Adaptability or versatility
If conventional TDLAS systems use standard optical components, then the system can detect common gases, but the range of detectable molecules is limited
Solution Approach 1:
The patent changes the optical parameters by using reflective optics designed to work across a broad bandwidth including mid-infrared, near-infrared, and visible regions. This parameter change enables the system to detect a wider range of molecules with different absorption characteristics, expanding versatility while maintaining detection sensitivity through optimized optical path length and light intensity management.
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
The system increases detection sensitivity and reduces installation complexity and maintenance costs by maintaining sufficient light intensity and expanding the range of detectable molecules, including carbon monoxide and oxygen, through the use of a single optical head and reflective optics.
Implementation Method 1
pitch reflective optics on a first side of the combustion zone that collimate MIR electromagnetic energy from an input fiber
Implementation Method 2
a reflector on a second side of the combustion zone that reflects collimated MIR electromagnetic energy
Implementation Method 3
catch reflective optics on the first side of the combustion zone that focus reflected MIR electromagnetic energy into an output fiber
Implementation Method 4
TDLAS systems monitor the presence or concentration of gases within combustion process chambers and in combustion zones
Data Source
AI summary
A combustion-zone chemical sensing system (100) is disclosed that includes pitch reflective optics (110) that collimate MIR electromagnetic energy from an input fiber (150), a reflector (120), catch reflective optics (112) that focus reflected MIR electromagnetic energy into an output fiber (152), and a detector (140) to detect MIR electromagnetic energy from the output fiber. An optical head (102) for sensing a combustion zone (104) is disclosed that includes pitch reflective optics (110) that collimate MIR electromagnetic energy from an input fiber (150) towards a reflector (120), catch reflective optics (112) that focus MIR electromagnetic energy, reflected from the reflector, into an output fiber (152), and an alignment housing that interfaces with structure adjacent the combustion zone. A method for determining gas concentration within a combustion zone is disclosed that includes collimating MIR electromagnetic energy exiting from an input fiber to traverse a combustion zone and focusing reflected MIR electromagnetic energy from the combustion zone into an output fiber.