基于TDLAS的煤矿用激光甲烷传感器的设计

Design of Laser Methane Sensor for Coal Mine Based on TDLAS

针对目前煤矿使用的甲烷传感器存在精度低、稳定性差、易受其他气体影响的问题,设计了一种基于谐波检测技术的激光甲烷传感器,并详细分析了TDLAS(Tunable Diode Laser Absorption Spectroscopy)基本原理。对传感器的系统总体设计、激光器及控制电路、光电转换及前置放大电路、RS485电路、频率信号电路、系统软件设计进行了重点介绍。同时分别对催化甲烷传感器、红外甲烷传感器和激光甲烷传感器通入标准甲烷气样和柴油车尾气进行测量,结果表明激光甲烷传感器检测精度高、误差小、不受交叉气体的干扰,符合国家煤矿安全标准的各项要求,能进一步保障煤矿的安全生产。

Aiming at the low precision,poor stability and susceptibility to other gases of the current methane sensors in coal mines,a laser sensor based on harmonic detection is designed,and the basic principle of TDLAS is analyzed in detail.The overall design of sensor system,laser and control circuit,photoelectric conversion and preamplifier circuit,RS485 circuit,frequency signal circuit and system software design are introduced emphatically.At the same time,the catalytic methane sensor,infrared methane sensor and laser methane sensor are respectively introduced into the standard methane gas sample and diesel vehicle exhaust gas for measurement.The results show that the laser methane sensor has the advantages of high detection accuracy,slight error and no interference from cross-gas.In accordance with the requirements of the National coal mine safety standards,it can further ensure the safe production of coal mines.