Interference photoelectric smoke and fire detecting method and its device

Abstract

The invention relates to interference photoelectric sensing smoke and fire detection method and device. The method includes: a. the light from the light source is divided into two beams with an optical splitter, one beam is emitted to the oscillation reference reflecting mirror, another beam is emitted to the target smoke sensing part; the scattering light generated by smoke and reflected light from the reference reflecting mirror are returned to the splitter to be superposed and carries on interference, and generates interference light signal; b. receives the interference signal with the photoelectric detector, and it is converted into interference photoelectric signal; c. the signal processing and analyzing device receive the interference signal, amplifies and processes them, judges if there has scattering light signal form fire smoke. The invention uses optical interference theory, upgrades the detection signal-to-noise ration and flexibility; the device needs not detection chamber and smoke absorbing device, it can be put into the open space to be detected, it can realizes the early detection to fire. The interference signal can be transmitted in fiber.

Description

technical field [0001] The invention belongs to the technical field of fire detection, in particular to an interference photoelectric smoke fire detection method and a device thereof. Background technique [0002] Most of the existing fire detection technologies are based on three types of principles: detecting smoke, detecting temperature, and detecting optical radiation. Among them, the smoke-sensitive fire detection technology is the mainstream technology used in the world at present, and it is divided into ion-sensing smoke fire detection technology and photoelectric smoke fire detection technology. Although the detection and response performance of the former to smoke of various particle sizes is relatively balanced, because its core component is the 241 americium radioactive source, there are environmental protection problems that cannot be ignored in the aspects of manufacturing, storage, transportation, use and scrap disposal, as well as the impact on humid environme...

AI Technical Summary

Problems solved by technology

In this way, in the early stage of the fire, the early fire cannot be detected before the smoke enters the barrier of the detection room; at the same time, its ability to resist ambient light interference is poor

In addition, in the existing technology, the weak scattered light intensity produced by the smoke on the incident light is obtained by the photoelectric conversion of the photodetector and the amplification of the electrical signal. Due to the thermal noise of the photodetector, the detection signal of the weak light The noise ratio decreases, resulting in a decrease in sensitivity; in addition, after the photoelectric conversion, when the weak electrical signal is amplified, the system's ability to resist environmental electromagnetic interference is poor, which is likely to cause false alarms and reduce reliability

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