The Research On Integrated Technology Of Gas Chromatography、Pre-concentrator And Surface Acoustic Wave Gas Sensor

With the development of society, the safety of public environment and industrial production has aroused people’s concern. In many detection objects, the analysis and detection of mixed gas in the environment is an important part. For the existing mixture of gas analysis and detection equipment, most of the detector is cumbersome because of the harsh working conditions. Meanwhile the equipment is difficult to popularize because the instrument cannot sampling automatically.SAW gas sensor is an alternative detection solution in small gas detection instrument because of its high sensitivity and small size characteristics. Gas phase chromatography can separate the mixed gas accurately and efficiently. Gas enrichment techniques can be used for environmental atmosphere sampling. This paper mainly studies the integration technology of enrichment device, gas phase chromatography and saw gas sensor in mixed gas analysis instrument.In this research, there is no standardization of the gas enrichment device, gas chromatography and SAW gas sensors. Therefore, according to previous document surveys, the cycle propulsion research methods of test, analyze, and optimize were used. Optimized reasonable integration scheme and controlling parameters were gained by a number of experiments.In the process of studying the integrated control methods of pre-concentrator, the development of enrichment device was summarized and analyzed appropriately. The test scheme of the performance of the concentrator is proposed according to analyzing the working characteristics and test conditions. A fast heating pulse generation circuit based on a single steady state trigger is proposed. The heating effect of different power supply voltage and the performance of the pre-concentrator were tested. The enrichment rate of the tubular concentrator by fast heating is improved to 56. Cryogenic adsorption enrichment device is designed and tested. It is found that cryogenic temperature can significantly improve the rate of enrichment of enrichment device. It was showed that desorption peak height of pre-concentrator enriching at cryogenic temperature is 2 times higher than that of the desorption peak at room temperature.The characteristics and composition of gas chromatography were introduced in this paper. The automatic sampling method based on second enrichment was designed and accomplished. The sampling time of the column was reduced to half of the sampling time with single enrichment.About the surface acoustic wave gas sensor, the structure, principle and the sensitive mechanism about the SAW device and SAW gas sensor were introduced. The driving circuit and counting module were designed for the double ended resonance type SAW device. The gas chamber of the SAW gas sensor is designed and the complete sealing of the gas chamber was realized. Also a scheme of gas chamber for SAW gas sensor as gas chromatographic detector is proposed. At last, a method based on similarity degree to identify the response peak of SAW gas sensor and calculate the position of the response peak was proposed in this paper. The source code and identify calculation results of example response data were given.