Research On Automatical High-Precision Mixed-Gas System

At present, the precision and efficiency of an automatic mixed-gas system with large volume capacity is low in factory. Thus it is difficult to meet the production requirements. As a result, this situation affects the quality of gas products and the development of new products. Based on the method of PVTt, the automatic mixed-gas system with high precision is developed. This system consists of a data-acquisition card, pressure sensors, proportional valves, air control values and Solenoid valves and so on.Firstly, the mixed-gas principle and the mixed-gas method is researched in this thesis. The interchangeability of gas and the data calculation of gas mixture is discussed. On the basis of study on the method of gas flow meters, the high-precision method of PVTt is proposed. In addition, Temperature and flow errors affecting precision of system is deeply discussed and Solutions are proposed.Then, the thesis makes out the research work from the overall plan, the system software and hardware. Focusing on the high-precision pressure signal acquisition, raw gas flow precise control, data acquisition modules procedures, the thesis makes an in-depth exposition for their realization.At last, the Gas Chromatograph is introduced, including the principle, internal parts, performance indicators, operation steps. The paper lists lots of testing data, which were obtained by the Gas Chromatograph, and uses statistic theory to analyze those data. According to analysis results, the paper summarizes the precision of the mixed-gas system.