Research On Optical Fiber Coal Mine Gas Sensor

In recent years, the coal gas explosion occurs frequently, people’s lives and property ofthe country has caused serious harm.Because methane gas is the main ingredient in the coalgas, so detecting methane gas has become the key area of scientific research. The traditionalanoptical type of methane gas sensor can check to a low concentration of methane gas, butthey have many shortcomings such as the response of the sensor slow, vulnerable topollution, short life and hard to monitor continuously in real-time in the large scale. Thispaper studies methane gas sensor system based on the optical fiber absorption spectrum,which combines optical fiber technology and weak photoelectric signal processingtechnology, realizes real-time, rapid and efficient testing. And if we change the light sourceand the corresponding photoelectric devices, it can also achieve the real-time distributed tomany kinds of gas detection.The first chapter presents the significance of gas detection, the characteristic of anopticaltype and optical fiber type gas sensor and research status of mine gas sensor; The secondchapter presents the choiced absorption characteristics of the gas molecular, absorptionlinear and absorption width, and analyzes the absorption of methane gas spectrum line; Thethird chapter researchs the principle and characteristic of the scheme of several detectiontechnology based on spectrum absorption, and gives single point and more detection systemframework of the optical fiber methane sensor; The fourth chapter designs all the parts of thesingle point optical fiber methane sensing system, given the design principle of the variousparts and choiced devices; The fifth chapter tests the sensing system and then analyzes theexperiment results; The sixth summarizes this article, points out the defects of the systemand discusses the application of this technology.The experimental results of the fifth chapter show that this system in concentrationbelow5%,0.3%was the biggest error detection; in concentration higher5%, the testingerror increases,5%was the maximum error. The experiment test also shows that the systemhas a good stability and sensitivity, system resolution was620PPM.