In view of the problem that the environment in local mine is complex, which makes it difficult to extract weak methane gas signal, a new methane detection technology based on dual difference was proposed according to the principle of infrared absorption spectrum. The detection technology adopted two wavelength-two path differential detec- ting structure and got light born voltage by a kind of monochromatic light＇ s twice difference passing the detector with different wavelength. Then it got outputs by AD7794 chip achieving two light signals＇ division. Finally the concentra- tion back-in-deuced formula was obtained through the measurement of variable concentrations of the methane gas in- jected into a new kind of gas chamber with different length which was designed by Ring-down cavity. The experimental results show that adopting dual difference can extract weak methane gas signal more effectively, and solve the perturba- tion problem of light path, and get higher precision and accuracy with error equal to 1%%针对煤矿井下环境复杂,难以提取瓦斯（甲烷）气体的微弱信号问题,根据红外光谱吸收原理,提出一种新的双差分瓦斯检测技术。它采用双光路双波长方法,先后两次射入不同波长的单色光,通过两次差分经过探测器得到光生电压。然后经AD7794芯片实现两路光信号相除得到输出,最后对不同浓度的甲烷气体通过不同长度的新型Ring-down腔气室进行测量得到其浓度反演式。实验结果表明,采用双差分检测技术,有效地提取了瓦斯气体微弱信号,解决了光路扰动问题,具有较高的精度和准确度,其误差为1%。
展开▼
