Chamberless Smoke Detection Using Intersecting Light Cones
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Solution Overview
Problem
Conventional smoke detectors in aircraft suffer from false alarms due to unwanted airborne particles entering the sensor chamber, which can lead to increased sensitivity and power consumption, and lack effective air quality monitoring capabilities for PM2.5 and PM10 particles.
Innovation Solution
A chamberless smoke detection system utilizing multiple light sources emitting light cones with intersecting symmetry axes, combined with light sensing devices and a polarizing filter to discriminate particle types, allowing for robust smoke detection and indoor air quality monitoring, including PM2.5 and PM10 particle detection, without the need for additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a chamber is used to protect the measurement volume, then measurement integrity is improved, but unwanted particles can still enter and cause false alarms
Solution Approach 1:
The patent removes the chamber entirely from the detector design, transitioning from a chamber-based to a chamberless architecture. This extraction eliminates the chamber that previously trapped particles causing false alarms, while maintaining measurement integrity through alternative means (multiple light sources with intersecting symmetry axes and particle discrimination algorithms).
Solution Approach 2:
The patent changes the detection parameters by using multiple light sources emitting at different wavelengths (e.g., 405nm UV, 450nm blue, 940nm IR) and analyzing scattered light characteristics. This multi-parameter approach enables particle discrimination without a physical chamber, resolving the contradiction between protection and false alarm prevention.
2Reliability
If light sources are constantly on to maintain detection capability, then detection reliability is improved, but power consumption and user nuisance increase
Solution Approach 1:
The patent implements periodic or on-demand activation of light sources rather than continuous operation. The system can activate specific light sources based on detection needs, enabling reliable detection while significantly reducing power consumption and eliminating constant light exposure to users.
3Object-affected harmful factors
If chamber inlets have controlled dimensions to prevent particle entry, then false alarms are reduced, but smoke particle diffusion becomes more difficult
Solution Approach 1:
The patent removes the chamber with its restrictive inlets entirely, replacing it with a chamberless design that uses multiple light sources with intersecting symmetry axes. This eliminates the bottleneck effect of controlled inlets while maintaining false alarm reduction through particle discrimination based on scattered light analysis.
4Object-affected harmful factors
If no chamber is used to eliminate particle trapping, then false alarms are reduced, but measurement volume protection is compromised
Solution Approach 1:
The patent employs multiple light sources (UV, visible, IR wavelengths) that serve both detection and particle discrimination functions simultaneously. This multi-functional approach provides measurement integrity without a chamber, as the combined light scattering analysis from different wavelengths enables reliable smoke detection and false alarm discrimination.
Solution Approach 2:
The system uses a composite approach combining multiple light sources with different wavelengths and a polarizing filter to create a robust chamberless detection system. The intersection of light cones from multiple sources creates overlapping measurement volumes that maintain integrity without physical protection, while the polarizing filter adds another layer of particle type discrimination.
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 provides enhanced detection capabilities with reduced false alarms, improved sensitivity, and integrated air quality monitoring, meeting aerospace application requirements while minimizing power consumption and nuisance from constant light exposure.
Implementation Method 1
use near infrared light, or lights of other wavelengths, scattering inside a small plastic chamber
Implementation Method 2
a polarizing filter optically coupled to a respective one of the light sensing devices wherein an airborne particle type is discriminated via the use the polarizing filter
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3A~3C
AI summary
A system for smoke detection and indoor air quality monitoring, comprising: two or more light sources (102, 104) configured to emit light into a monitored space, wherein at least two of the two or more light sources emit respective light cones each having a respective symmetry axis, wherein the symmetry axes of the respective light cones intersect one another; one or more light sensing devices (106, 108, 110) configured to receive scattered light; and a processor operatively connected to the one or more light sensing devices to evaluate the scattered light for the presence of one or more indoor air quality conditions in the monitored space.