Application in coal mine of fiber methane monitoring system based on spectrum absorption

摘要

A novel all fiber optic multipoint methane monitoring system is researched for remotely detecting the concentration of methane gas in coal mines. A 1653nm distributed feedback (DFB) laser is used as the light source, by taking the triangular signal to modulate the light frequency of the DFB laser. The concentration of methane can be monitored and displayed on the screen. And the function of the sounding and light alarm bell and communication are achieved. Since the sensor head is made without any active electrical components, it is intrinsically safe when used in the hazard environment such as coal mines. With the use of a optical fiber links between monitor and sensor header, the system can provide a remote and online monitor/measurement information, which makes this system particular suitable for the safety monitoring in the coal mines. The monitor unit can connect to multi-sensors. The measurement range of each sensor can be selected according to the customer's demand during 0-100%. The results show that the system has good performance in stability and sensitivity. It is an innovative "total solution" for coal mine safety monitoring and hazard warning.