The Design And Application Of Optic Fiber Gas Monitoring System

Coal is one of the most important energy in China.Coal mine is the main production unit of coal.The number of coal mine is over 300,000 in China,which contains more than 40% of the coal mines with high gas and coal and gas outburst.Gas accident deaths accounted for ninety percent of the total casualties.The gas to ensure mine safety has become a top priority.Mine has been the gas monitoring and control on the most important position,so effective real-time detection of underground gas will play a huge economic and social significance in the coal industry and the lives of the miners.This article firstly discuss common detection method of optic fiber methane sensor and development of optic fiber methane sensor at home and abroad.Secondly,it studied optic fiber methane detection principle,chose the suitable absorption spectra of methane.After comparing the characteristics of different detection method,we selected the fitting solution from the usual absorption gas detection method based on implementation,reliability,low cost and other factors to consider.Thirdly,a gas monitoring system for detecting methane had been designed.Lower machine had also been designed from hardware, software and etc.C8051 micro-controller based on hardware to achieve the laser current control, optical signal acquisition,data processing,keyboard,display and other functions,it could independently analyze data,alarm,but also communicate with the host computer. VB-based software development,can communicate with lower computer,alarm,control external devices,such as starting or stopping functions.Different sensors for a variety of use environment was designed to solve the traditional electronic sensors and infrared sensors used in the field which had issues such as frequent maintenance,unstable performance,and etc.Gas sensors used underground tunnel enhanced anti-dust and anti-water capabilities,it had a longer maintenance cycles and stability.Gas sensors used on drainage pipeline enhanced anti-water and gas diffusion function,it had a higher accuracy and response speed.Finally,the gas monitoring system carried performance test and installed and tested in coal mine return airway and on gas pumping pipes.while ensuring the use of function,the system increased the sensitivity to 20ppm,accuracy was improved to 0.7% of the true value.The maintenance cycle extended to six months.Comparing with other systems,this system had obvious advantages in accuracy,stability and etc., it ensured that the sensor was be a great site to ensure the safety of the work environment.