The Development Of Methane Detection System Based On Infrared Absorption

Recent years, with Chinese rapid development and increasing coal production, security incidents caused by excessive Gas concentration have occurred sometimes in the production. The effective way to prevent such accidents is to detect mine Gas concentration accurately and timely. Infrared absorption Gas detection system is characteristic of high sensitivity, short response time and hard poisoning, therefore, its study has practical significance.In this thesis methane is detected, which is the main component of Gas. By the analysis of selective absorption of infrared gas, the absorption line of methane gas is determined and the theoretical basis of gas absorption measurement is obtained. DSP chip is chose as a control, because of the high-speed data processing performance. The system can realize the sample of weak Gas signal and the design of corresponding digital filter, in order to achieve a precise measurement of methane concentration.System development including hardware and software aspects:on the hardware side, light source, the gas chamber and detector provided by the system are selected, meanwhile, reasonable source driver circuit, amplification filter circuit, weak signal conditioning circuits, analog-digital conversion circuit and DSP control circuit are designed; on the software side, system initialization, temperature acquisition and measurement, signal sampling, digital filtering and other aspects of software design are completed.Finally, the relevant system experiments are completed and error analysis of experimental data is done. The result shows that the infrared absorption gas detection system achieved the expected objective, with a certain degree of accuracy and stability.