Three wave length total scattering laser smoke sensing fire hazard detecting method and its apparatus

Abstract

The method and device for detecting a smoke-sensing fire with a three-wavelength full-scattering laser of the present invention are characterized in that smoke or aerosol is sucked into the smoke detection chamber by an air pump, and three laser beams of different wavelengths are emitted by the laser and injected into the smoke detection chamber to be absorbed by the smoke. After attenuation, it is emitted to the photoelectric receiving tube and converted into an electrical signal. After being amplified, the multi-channel data acquisition card performs A / D conversion, and then it is sent to a microcomputer to analyze and process the attenuation data of the three beams of laser light to obtain the wavelength of the three beams. The extinction coefficient ratio is used as the input of the smoke recognition neural network. The smoke recognition neural network analyzes and judges the input data. When it is confirmed as "fire smoke", it controls the alarm controller to drive the fire linkage alarm equipment to issue an alarm. Fire aerosol" will not call the police. The invention can accurately and reliably identify fire smoke and non-fire aerosol, and has the advantages of intelligent identification, consistent sensitivity, high reliability, strong ability to resist environmental interference, and the like.

Description

Technical field: [0001] The invention belongs to the technical field of fire detection, in particular to a laser smoke detection method and a device thereof. Background technique: [0002] Existing fire detectors include smoke-sensing, temperature-sensing, photo-sensing, etc. Smoke-sensing fire detectors can be further divided into photo-sensing smoke-sensing detectors and ion-sensing smoke-sensing detectors. One of the most widely used detectors in the world. According to the Proceedings of the Third Asia-Oceania Symposium on Fire Science and Technology, June 10-12, 1998, pp.319-331, the existing photoelectric smoke detectors are Using smoke particles to scatter and absorb incident light to detect the concentration of smoke and then realize fire alarm, it has the characteristics of no radioactive pollution, strong adaptability, and low cost. In terms of performance, there are the following defects: ①Due to the different relative sensitivities of smoke particles with diffe...

AI Technical Summary

Problems solved by technology

According to the Proceedings of the Third Asia-Oceania Symposium on Fire Science and Technology, June 10-12, 1998, pp.319-331, the existing photoelectric smoke detectors are Using smoke particles to scatter and absorb incident light to detect the concentration of smoke and then realize fire alarm, it has the characteristics of no radioactive pollution, strong adaptability, and low cost. In terms of performance, there are the following defects: ①Due to the different relative sensitivities of smoke particles with different particle sizes to incident light scattering, when the particle size of smoke particles is less than 0.4 μm, scattered light cannot be produced, and the relative sensitivity is poor; It can be divided into invisible smog, translucent white, gray smog, and opaque black smog. For completely transparent invisible smog, photoelectric smoke detectors cannot detect it because it cannot scatter light; while black smog has a strong effect on light. The absorption and shielding effect can only produce weak scattered light, and it can hardly be detected; ③The existing light receiving device is easily affected by environmental interference, and it is easy to be damaged when there is dust, water vapor, oily smoke, wind and electromagnetic interference. Causes false alarms and low reliability; ④It cannot be used in special places with long-term smoke (such as temples, etc.)

[0003] The smoke detection experimental system introduced in Volume 21, Issue 2, P79-81 of "Applied Laser" is mainly composed of power supply, laser, collimating lens, test smoke box, receiving lens, photoelectric receiving tube, signal amplifier and computer data acquisition system. Through the monitoring of the attenuation of the laser by the smoke, after inversion calculation, the characteristic parameters such as the concentration, average particle size and particle size distribution of the smoke are obtained, so as to identify different types of fire smoke and interference sources, but there are the following defects: ① The laser is powered by a universal power supply, which cannot guarantee the stable light intensity of the laser; ②There is no alarm function, and the fire linkage alarm equipment cannot be driven; ③The smoke enters the test smoke box by diffusion, passively waiting for the smoke, and the response ability is poor; ④Three beams of laser The cross arrangement is adopted, all pass through the center of the smoke box, the optical path length is equal to the diameter of the smoke box, when the smoke concentration is low, the detection sensitivity of the photoelectric receiving tube is very low

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