Photoelectric smoke sensing fire detecting method and apparatus based on depolarization rate

Abstract

The invention relates to a photo-electricity smoke sensing fire detection method and device based on depolarizing rate. Its features are that light beam is emitted to the smoke particle by the polarizer; the plane of the incidence beam is used as scattering base plane; the up and down sides of the receiving plane normal to the scattering base plane are set same two the first and second photo-electricity receivers both of which are aimed at the particle scattering center; and one of which end is set one polarization verifying machine; the optical axis of the polarizer and polarization verifying machine are normal to the scattering base plane. It uses the change of the polarization feature in particle light scattering to identify ash smoke particle, dark smoke particle, dust, water vapor interference source particle, reduce the rate of false alarm of the smoke sensing detecting, increase its response sensitivity.

Description

Technical field: [0001] The invention belongs to the technical field of fire detection, in particular to a photoelectric smoke detection method and device based on depolarization rate. Background technique: [0002] The "Fire Safety Journal" (Fire Safety Journal 1, 1997, Volume 29, pages 77-85) published in the UK pointed out that smoke particles are one of the important characteristic parameters in the early stage of fire, and the early detection of fire based on the light scattering principle of smoke particles is very important. One of the most important methods of fire detection. According to Maxwell's electromagnetic scattering theory, the process of particle light scattering contains three important information, namely light intensity, polarization and phase, among which phase information is more difficult to obtain, while light intensity and polarization information is relatively simple to obtain. Existing photoelectric smoke detectors, such as the smoke detection te...

AI Technical Summary

Problems solved by technology

Existing photoelectric smoke detectors, such as the smoke detection technology mentioned in U.S. Patent US2002084907, Japanese Patent JP2004227452 and European Patent DE69608363D, only use the scattered light intensity of smoke particles as the criterion for detecting fires, and fail to The use of polarization information that more deeply reflects the essential characteristics of particle light scattering cannot reliably and effectively identify gray smoke, black smoke, dust, and water vapor interference source particles, so it is impossible to fundamentally eliminate false alarms caused by interference source particles. The consistency of the response sensitivity of different types of smoke particles is poor, which limits the further improvement of sensitivity

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