Design Of The High Precision Infrared Optical Gas Sensor

The increasing developing economy brings more and more serious environmentalproblems, and high-precision gas detection techniques play a more and more important role inthe areas of hazardous chemical monitoring and environmental pollution control. Byinvestigating laboratory available sensors, which do not have the advantages of the highdetection precision and convenience etc, those cannot meet the development needs of society.Considering the current testing requirements in the field of gas detection, especially for thatinfrared absorption technique has many advantages in this field, we presents a high-precisioninfrared gas sensor for the detection of methane.This article introduces the principle of high-precision systems methane sensor,preparation and performance testing calibration and focused on several aspects of the impactsensor detection performance. The main research work is as follows:Firstly, elliptical chamber structure is proposed. The elliptical chamber structure hashigher infrared absorption rate by theoretical analysis and optimized by experiment;Secondly, weak signal detection module is designed. A third-order filter amplifier circuitwas designed to process the output current signal of pyroelectric crystal and become withinone voltage;Thirdly, software algorithms are fixed. On the one hand, the gas concentration andintensity of the mathematical model is processed by temperature compensation and opticalmodel correction; on the other hand, the method of quadratic interpolation look-up table isused in the experimental calibration, which further reduces the calculation error thoughparabola instead of straight line.In summary, this article major describes three aspects to improve the detection accuracyof the sensors. The sensors were calibrated and tested on response time and detectionaccuracy by gas distribution system, this experiment results show that the error of the sensor is controlled within0.04%and the response time of the sensor is also shortened to20s. Aftercomparing the similar products at home and abroad, it is clear that this new designed sensorexhibits enhanced performances including higher detection sensitivity, lower detection errorand shorter response time.