Optimization Method And Technical Research Of Odor Detection System

With the development of economy,the human living environment is increasingly suffering trample upon,the destruction of the environment causes great damage to human health,the odorous gas pollution is one of them.Odorous gas pollution widely exists in industrial,agricultural and urban construction.Because the odor research in China started late,so there is still a gap compared with advanced countries in the world about detection technology.With people-oriented thought is deeply rooted in the hearts of the people,the development of a rapid accurate effective odor gas detection system is urgently needed.The topic uses a composite odor examination system which is based on the sensor array.The system is divided into three parts that are upper system,middle system and lower system,PC system regards industrial control computer as the carrier,whose programming language is graphical language LabVIEW.The middle and lower machine system are based on embedded MCU as the core and install the corresponding hardware circuit configuration.Lower machine is responsible for collecting the data,and then transports the data to middle machine system,the middle machine through the preliminary processing,and then hands them in upper machine system for deeper processing,the upper machine processes the stench of odor gas concentration.The completed content of this thesis mainly has:1.The structure of gas path is optimized,the preprocessing module is installed in the gas path parts and style of the pump changes absorption to blow;2.The zero circuit of metal oxide sensors are optimized,so that we solve the existence of temperature drift and drift for a long time;3.The program of middle and lower machine are compiled.Compared with the old process,the new C language program becomes simple and readable,besides,the program execution uses less time,so that we improve the efficiency of the experiment;4.In terms of experimental methods,we optimize the choice of the background gas,propose in laboratory experiments with background gas and dilut with background gases to remain consistent.For optimization of the system,we do lots of experiment,the experiment selectes gas objects include two categories: elemental gas methyl sulfide and dimethyl disulfide;Mixed gas mainly is a mixture of sulfide,through many tests,the optimization system is better than before optimization experiment.The limits of elemental gas methyl sulfide and dimethyl disulfide are respective 40 PPB and 10 PPB;The limit of detection concentration(LDC)of mixed gas can reach 5 PPB.