Development of gas fire detection system using tunable diode laser absorption spectroscopy

International Conference on Energy Engineering and Environmental Protection 2016

能源学;生态环境科学

Jiang, Y.L.^1 ; Li, G.^1 ; Yang, T.^1 ; Wang, J.J.^2

College of Civil and Environmental Engineering, Anhui Xinhua University, China^1

State Key Laboratory of Fire Science, University of Science and Technology of China, China^2

关键词: Detection sensitivity;    Fire-detection method;    Fire-extinguishing systems;    Physical parameters;    Second harmonic signals;    Smoke concentration;    Tunable diode laser absorption spectroscopy;    Wavelength modulation;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/52/1/012092/pdf
DOI  :  10.1088/1742-6596/52/1/012092

学科分类：环境科学（综合）

来源: IOP

【 摘 要 】

The conventional fire detection methods mainly produce an alarm through detecting the changes in smoke concentration, flame radiation, heat and other physical parameters in the environment, but are unable to provide an early warning of a fire emergency. We have designed a gas fire detection system with a high detection sensitivity and high selectivity using the tunable semiconductor diode laser as a light source and combining wavelength modulation and harmonic detection technology. This system can invert the second harmonic signal obtained to obtain the concentration of carbon monoxide gas (a fire characteristic gas) so as to provide an early warning of fire. We reduce the system offset noise and the background noise generated due to the laser interference by deducting the system background spectrum lines from the second harmonic signal. This can also eliminate the interference of other gas spectral lines to a large extent. We detected the concentration of the carbon monoxide gas generated in smoldering sandalwood fire and open beech wood fire with the homemade fire simulator, and tested the lowest detectable limit of system. The test results show that the lowest detectable limit can reach 5×10-6; the system can maintain stable operation for a long period of time and can automatically trigger a water mist fire extinguishing system, which can fully meet the needs of early fire warning.