Research on Method of Detecting Methane Concentration of Coal Mines Based on the Difference of Two State Distributed Feedback Laser
This paper presents a new method of detecting Methane Concentration of Coal Mines: the Method of Difference of Two States (MDTS). A special square current driving pulse makes the Distributed Feedback Laser (DFB) working at two wavelengths, one at strong absorption peak, while another at sick one. After the laser goes through Methane gas , the laser power will change respectively ,comparing the change, we can get the Methane Concentration. In this paper, the light path length is 20 cm, the two wavelengths are 1650.948nm and 1650.8161nm. At first , the gas cell be filled with purge nitrogen, measured the light power difference (D0) between the wavelengths, get the zero concentration point of the system ,then filling methane of various concentration: 0.874 % ~8.737% v/v, measured the light power difference (Di,i=1,2,3…) between the two wavelengths again. Recorded the ratio (Di / D0) of various concentration .The result is consistent with the theory. Using this method, the fluctuation of the light power can be eliminated, zero concentration point of the system can be easy gotten, no reference gas cell need, simplified sensor design and lower the cost of the system.
Methane1 Distributed Feedback Laser Narrow-band Absorption
ZHANG Yue ZHANG Jilong TIAN Erming LI Xiao WANG Zhibin
National Key Laboratory For Electronic Measurement Technology, Taiyuan, 030051
国际会议
北京
英文
2007-08-05(万方平台首次上网日期,不代表论文的发表时间)