Fire Detection Using Staggered LED Wavelengths
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Solution Overview
Problem
Existing fire detection methods using the scattered light principle face challenges in accurately distinguishing between fire and nuisance particles like dust or steam, leading to potential false alarms and inefficient energy usage.
Innovation Solution
A method and device that radiate light pulses of different wavelengths into a scattered light volume, measuring and comparing scattered radiation intensities to determine quotients, which are then compared to specific values to differentiate between fire and nuisance particles, and output a fire alarm only when certain conditions are met, thereby reducing false alarms and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light pulses of multiple wavelengths are continuously radiated to improve detection accuracy, then measurement precision is improved, but energy consumption increases
Solution Approach 1:
The patent applies periodic action by radiating light pulses of different wavelengths in alternating sequences rather than continuously. The system switches between first wavelength light pulses (for forward scattering measurement) and second wavelength light pulses (for backward scattering measurement), achieving comprehensive detection data while minimizing energy consumption through pulsed, time-multiplexed operation.
Solution Approach 2:
The patent applies preliminary action by first measuring forward scattering with the first wavelength to assess particle presence, then conditionally proceeding to backward scattering measurements with the second wavelength only when needed. This staged approach allows the system to perform preliminary assessment before committing additional energy resources.
2Reliability
If multiple scattered radiation intensities are measured to differentiate fire from nuisance particles, then reliability is improved, but device complexity increases
Solution Approach 1:
The system uses periodic action to alternate between measuring forward scattering intensities (I1F, I2F) and backward scattering intensities (I1R, I2R) at different wavelengths. This time-multiplexed measurement approach enables comprehensive data collection for reliable fire differentiation without requiring all sensors to operate simultaneously, thereby managing device complexity.
Solution Approach 2:
The patent applies parameter changes by utilizing light pulses of two different wavelengths (first wavelength and second wavelength) to probe the scattered light volume. By measuring how particles scatter these different wavelengths differently in forward and backward directions, the system creates a distinctive signature that reliably differentiates fire particles from nuisance particles without adding complex hardware.
3Productivity
If light pulses are radiated at high frequency to improve detection speed, then productivity is improved, but energy consumption increases
Solution Approach 1:
The system implements periodic action by using pulsed light radiation at optimized frequencies for detection speed while maintaining energy efficiency. The control unit alternates between different wavelength pulses in a time-multiplexed manner, achieving rapid detection cycles without continuous energy expenditure, thus balancing productivity with energy conservation.
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 enhances the reliability of fire detection by accurately differentiating between fire and nuisance particles, while also being energy-efficient by minimizing unnecessary light pulse radiation.
Implementation Method 1
detectors using the scattered light principle, light pulses of a first wavelength λ1... and light pulses of a second wavelength λ2... are radiated into a common scattered light volume or measuring volume
Data Source
AI summary
Various embodiments may include a method for fire detection comprising: radiating light at a first wavelength into a scattered light volume and measuring a radiation intensity generated by forward scattering; radiating light at a second wavelength and measuring a second scattered radiation intensity generated by forward scattering; determining a first quotient from the scattered radiation intensities and comparing it to a first and second value; and if the first quotient lies between the first and the second value; radiating pulses at the second wavelength into and measuring a third intensity generated by backward scattering; determining a second quotient from the first and third scattered radiation intensity and comparing the second quotient with a third value; and generating a fire alarm if the second quotient exceeds the third comparison value.