Fire field multi- parameter laser wavelength modulated spectrum detection method and apparatus

Abstract

The invention discloses a fire scene multi-parameter laser wavelength modulation spectrum detection method and a device thereof, wherein, fire smoke products are treated through a smoke pre-treatment device and then pumped into a white cell through an air extracting pump; a multi-channel laser controller scans and modulates the wavelengths of a plurality of DFB lasers according to the time-sharing and multiplexing working mode, and all waves of laser share an optical fiber and are outputted sequentially through a wave combiner, then are aligned by a fiber collimator and sent to the white cell to detect the fire smoke products; a photoelectric detector converts light intensity signals of laser repeatedly reflected and absorbed by the white cell into electrical signals which are sent to two phase-locking magnifier modules for frequency selecting magnification so as to obtain a fundamental frequency component and a second harmonic component; a multi-channel data acquisition card converts output voltage signals of the phase-locking magnifiers into digital signals which are sent to a micro-computer for real-time data processing, so that the fire scene multi-parameter information containing the oxygen concentration of the fire scene, concentrations of various toxic gases and smoke concentration is obtained. The detection method and device can realize real-time on-line monitoring to fire scene multi-parameters, and have the advantages of being real-time, multi-component and highly sensitive, good selectivity of gas, high reliability and strong environmental disturbance resistance ability.

Description

Technical field: [0001] The invention belongs to the technical field of fire monitoring, in particular to a laser absorption gas analysis and detection method and a device thereof. Background technique: [0002] The multi-parameters of the fire scene include the oxygen concentration of the fire scene, the concentration of various toxic gases and the smoke concentration, which are important factors affecting the escape and rescue of people in a fire. Among the gas analysis and detection methods, the common detection methods at present mainly include the following: the electrochemical method using electrodes and electrolytes to detect gas; the electrical method using semiconductor gas device detection; using the refractive index or Optical methods for detecting gases by using properties such as light absorption. These methods have their own fields of application, but limited by the detection mechanism, the electrochemical and electrical methods have defects such as short sens...

AI Technical Summary

Problems solved by technology

[0003] ①Fourier Transform Infrared Spectroscopy (FTIR) can measure and analyze gas concentration in a wide infrared band. Although this method has high sensitivity and can realize simultaneous analysis and measurement of multiple toxic gases, it needs to use spectroscopic elements and scanning methods , and gas sampling is required, gas measurement and analysis can only be carried out in the laboratory, and online real-time detection of gas products at the fire scene cannot be realized

[0004] ②Existing optical methods, the optical path of gas detection equipment is relatively fragile, easily affected by environmental interference, and it is more difficult to monitor the smoke concentration at the same time

[0005] ③ Existing gas monitoring methods are difficult to achieve real-time online detection of multi-component gases

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