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

Abstract

A three-wavelength full-scatter laser smoke-sensing method for detecting fire accident includes such steps as pumping smoke or aerosol in smoke detecting chamber, emitting three laser beams with different wavelengthes in said chamber by laser device, attenuating them by smoke, received by photoelectric receiver to output electric signals, amplifying, A / D convertion, computer analysis to obtain their extinction coefficient ratio, analyzing by neuron network to recognize smoke, and driving alarm device if it is "smoke of fire accident".

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. Sexual defects include: [0003] ①Because the relative sensitivity of smoke particles with different particle sizes to incident lig...

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Problems solved by technology

[0003] ①Because the relative sensitivity of smoke particles with different particle sizes to incident light scattering is different, when the particle size of smoke particles is less than 0.4 μm, scattered light cannot be produced, and the relative sensitivity is poor;

[0004] ②Smoke produced by fire can be roughly divided into invisible smoke, translucent white, gray smoke, and opaque black smoke. For completely transparent invisible smoke, photoelectric smoke detectors cannot detect it because it cannot scatter light; Black smoke has a strong absorption and blocking effect on light, and can only produce weak scattered light, which is almost undetectable;

[0005] ③ Existing light receiving devices are easily affected by environmental interference. When there is dust, water vapor, oil fume, wind and electromagnetic interference, it is easy to cause false alarms and low reliability;

[0006] ④ It cannot be used in special places with long-term smoke (such as temples, etc.)

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