Long-Range Flame Detection Using Optical Concentrators and Filters
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Solution Overview
Problem
Current flame detection systems, particularly outdoor detectors, have limited detection ranges (30 to 120 meters) and are costly, leading to delayed fire detection in situations like wildfires, which can cause significant damage before intervention is possible.
Innovation Solution
A long-range flame detector system using non-imaging optical concentrators and pyroelectric detectors, with thermally isolated receiving surfaces and wavelength-specific filters, enhances detection range to approximately 900 meters by optimizing light collection and thermal isolation, allowing for early fire detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pyroelectric detectors are used for flame detection, then the system can detect a wide range of wavelengths from UV to deep IR, but the sensitivity is much lower compared to semiconductor detectors
Solution Approach 1:
The patent combines multiple pyroelectric detectors with different wavelength sensitivities into a single system, along with optical concentrators and filters, to achieve broad spectral coverage while maintaining adequate sensitivity through the synergistic effect of multiple detectors working together
Solution Approach 2:
The patent introduces optical concentrators as intermediary devices that concentrate light onto the pyroelectric detectors, and spectral filters as intermediaries that select specific wavelength ranges, thereby enhancing the detection capability of the inherently less sensitive pyroelectric detectors
2Length of stationary object
If current outdoor detection systems are used, then the detection range is 30 to 120 meters, but this is not long enough to reliably detect fires in remote areas before they spread significantly
Solution Approach 1:
The patent transitions from conventional planar detection approaches to a three-dimensional optical concentration system using parabolic cylindrical concentrators that focus light from a wide field of view onto the detectors, enabling long-range detection by utilizing the geometric concentration of light in space
Solution Approach 2:
The system performs preliminary detection at extended ranges by concentrating optical energy before the fire reaches critical stages, allowing early warning and giving sufficient time for intervention before the fire spreads to vulnerable areas
3Length of stationary object
If non-imaging optical concentrators are used to focus light onto pyroelectric detectors, then the detection range can be extended to approximately 900 meters, but the system complexity increases
Solution Approach 1:
The patent divides the detection system into separate functional modules: optical concentrators for light concentration, spectral filters for wavelength selection, and pyroelectric detectors for signal detection, allowing each component to be optimized independently while working together to achieve extended range
4Loss of energy
If pyroelectric detectors are placed in direct contact with optical concentrator exits, then thermal losses occur, but thermal isolation reduces detection sensitivity
Solution Approach 1:
The patent introduces an intermediary air gap between the optical concentrator exit and the pyroelectric detector, which acts as a thermal barrier to reduce heat loss while still allowing optical energy to pass through to the detector, thereby maintaining detection sensitivity while reducing thermal losses
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 enables early detection of fires at extended ranges, reducing damage by providing a detection range of 80 to 2000 meters, improving fire detection capabilities in challenging environments.
Implementation Method 1
A compound parabolic concentrator (CPC) is an example of a non-imaging concentrator. CPCs accept incoming radiation over a relatively wide range of angles.
Implementation Method 2
Pyroelectric detectors use a material in which temperature changes generate a current. Because light will increase the temperature of the material, pyroelectric detectors can be used for the detection of fires and other light sources.
Implementation Method 3
a first of the plurality of filters transmits light of a first wavelength range to a first of the detectors, and a second of the plurality of filters transmits light of a second wavelength range to a second of the detectors
Data Source
AI summary
A flame detector including: a plurality of detectors; a plurality of filters; a plurality of non-imaging optical concentrators having an entrance arranged to receive light incident on the flame detector and an exit arranged to deliver the light to a coupled detector. A first of the plurality of filters transmits light of a first wavelength range to a first of the detectors, and a second of the plurality of filters transmits light of a second wavelength range to a second of the detectors, wherein the second wavelength range is different from the first wavelength range.