Fiber Optic Smoke Detection Using Multi-Wavelength Scattering
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Solution Overview
Problem
Conventional smoke detection systems in aircraft face challenges in distinguishing between hazardous smoke and non-hazardous particulates, leading to false alarms, and require improved sensitivity for early fire detection while minimizing false alarms.
Innovation Solution
A fiber optic detection system that utilizes multiple wavelengths of light and light sensitive devices to differentiate between smoke and non-hazardous sources by analyzing scattered light patterns, with a control unit processing signals to determine the presence and magnitude of smoke, and optionally providing temperature data to other aircraft systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photoelectric smoke detection systems are used to detect smoke particles, then fire detection capability is provided, but false alarms occur due to inability to distinguish smoke from non-hazardous particulates
Solution Approach 1:
The system uses multiple wavelengths of light (different parameter values) to probe the smoke particles. By analyzing scattering patterns at different wavelengths, the system can distinguish between smoke and non-hazardous particulates based on their different optical properties, thereby reducing false alarms while maintaining fire detection accuracy
Solution Approach 2:
The patent introduces scattered light analysis as an intermediary measurement mechanism. Instead of directly detecting particles, the system uses light scattering patterns as a mediator to indirectly characterize particle properties, enabling discrimination between hazardous and non-hazardous particles
2Measurement precision
If higher sensitivity detection is implemented to enable earlier fire detection, then detection capability is improved, but the risk of false alarms increases
Solution Approach 1:
The system employs multi-wavelength light parameters to enhance measurement precision. By measuring scattering intensity at multiple wavelengths simultaneously, the system achieves higher sensitivity for early smoke detection while using the spectral information to distinguish true smoke signals from false alarm sources
Solution Approach 2:
The patent adds the wavelength dimension to the detection process. Instead of measuring only light intensity at a single wavelength, the system measures scattering across multiple wavelengths, creating an additional dimension of data that enables both higher sensitivity and better discrimination against false alarms
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 effectively reduces false alarms by accurately detecting smoke and providing early fire detection, enabling better control of fires while minimizing nuisance alarms and improving sensitivity for critical aircraft areas.
Implementation Method 1
A fiber optic cable (28) has a node (34) located at a termination point of the fiber optic cable (28). The node (34) is in communication with the ambient atmosphere. A light source (36) and a light sensitive device (38) are coupled to the fiber optic cable (28).
Implementation Method 2
Smoke detection systems utilize anisotropic light scattering to reduce false alarms. The anisotropic light scattering results in the number of photons being redirected from their original direction non-uniformly with respect to angle.
Implementation Method 3
The anisotropic light scattering results in the number of photons being redirected from their original direction non-uniformly with respect to angle. In practice, this can be accomplished utilizing a combination of opto-electronic detectors and light sources
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
A detection system for measuring the presence of one or more conditions in a predetermined area includes a fiber harness (30) having at least one fiber optic cable for transmitting light. The at least one fiber optic cable defines a node (34) arranged to measure the one or more conditions. The node is arranged such that light scattered by an atmosphere adjacent the node is received by at least one core of the fiber optic cable. A control system (50) operably connected to the fiber harness includes a light source (36) for transmitting light to the node and a light sensitive device (38) configured to receive scattered light associated with the node. The control system analyzes more than one signal corresponding to more than one wavelength of the scattered light associated with the node to determine at least one of a presence and magnitude of the one or more conditions at the node.