The Research And Design Of Photoelectric Smoke Detecors Using Forward/Backward Scattered Light Or Double Wavelengths Light

This article introduce the kind of point photoelectric smoke detectors and standards for testing production, analyse and show that this detector is't sensitive to black smoke and little diameter particle produced from the solid or liquid fire, and send out false alarm after detecting some aerosol such as steam,fog,fly ash. This article introduce fruits of research made for solving this problems in CHINA and other country.This article introduce the conception of Rayleight scattering,Mie scattering,Optical scattering,scattering angle of scattering theory , and introduce deduction relate to the design of forward/backward scattering smoke detector, research the principle and characteristic of point smoke detectors using scattered light or transmitted light, research and introduce means for distinguish factors that are not fire from the model of fire energy detect..This article compare the forward scattering detector and backward scattering detector based on Mie Scattering Theroy and experimentation, design the forward/backward scattering smoke detector that can detect four kinds of test fire in GB4715-2005 and the algorithm about relative ratio of photo intensity.For enhancing to ,this article study the design of photoelectric smoke detecors using double wavelengths light.This article analyse and show the principle of circuit,the protocol communicating to the fire alarm unit,the design of software and realization of pivotal technique such as low power,optical chamber of forward/backward scattering smoke detector.This article supply data of experimentation in designing the photoelectric smoke eetecor using forward/backward scattered light or double wavelengths light to validate the deduction and actual effect.