基于恒温谐波检测双回路瓦斯浓度仪研究

针对传统气体传感器检测范围窄、易中毒、使用寿命短等缺陷，提出基于恒温谐波检测的双回路瓦斯浓度检测系统。通过ATMEGA16实现低浓度的电化学检测电路切换高浓度的红外吸收检测电路，恒温惠斯通电阻电桥检测电路可减少温度场对传感器性能影响；应用谐波检测原理消除红外光路干扰，稳定光源的输出功率，提高灵敏度。利用拉格朗日插值定理进行温度补偿，可消除温度漂移带来的瓦斯浓度二值性问题，并能在5.3%瓦斯浓度处实现高精度的瓦斯爆炸预警。实验结果表明：双回路检测仪具有高灵敏度、测量范围广、精度高等特点，可应用在突出灾害时瓦斯大量涌出检测中。

Study on dual-circuits gas detector based on constant temperature and harmonic detection

In order to solve the traditional gas sensors characteristics such as narrow range,easy to poisoning,short service life,the dual-circuits gas detector based on theory of constant temperature and harmonic detection has been put forward. The system can switch from bridge detection circuit to infrared absorption detection circuit by ATMEGA16 to measure gas concentration,the principle of the harmonic detection merged into infrared absorption sensor which eliminated interference of light path,and stabilized power output of the infrared light source. This sys?tem can eliminate the binary problems resulted from temperature drift,and realize the high precision gas explosion warning at 5.3%by using the theory of Lagrange Interpolating Polynomial for temperature compensation. The experi?ment results show that the dual-circuits detector has properties of high sensitivity and precision,wide measurement range,etc,and it has higher application value.