| Thermal conductivity detector(TCD)is popular in gas chromatography detectors,it is widely used in the petrochemical,metuallugical,coal and other industries,TCD is an indispensable analysis tool.To analysis the qualitative and quantitative of analyte components,it's necessary to require gas analyzers of high sensitivity,fast response time,portable and other advantages.Since the micro thermal conductivity detector with high sensitivity,fast response,portable,and low power consumption,it has gradually occupied an important position in the field of thermal conductivity sensor.TCD is widely disposed in the gas chromatograph,and is also the important part of gas chromatograph.It can achieve gas-line analysis.Micro thermal conductivity detector is the research object in this paper,several key technologies are involved in the research work.it includes working principle and working environment of a TCD,the choose of thermal elements,the research and production of the micro thermal conductivity detector's cell body material and structures,the design of a constant current source,temperature control system,the design and application of SCM data acquisition system.First of all,the article describes the history and current development study of the TCD,and then discusses the basic theory of gas chromatography and the performance of TCD.Based on the theory,deeply analyzed its working principle,compared structural features between existing TCD and conventional mechanized TCD.At the same time,based on the theory of heat transfer finite element,to optimize and narrow the structure of TCD,using ANSYS software to simulate thermal steady-state.Since the change of Wheatstone bridge current flow will generate an error to the output signal of TCD,it is necessary to use constant current source.Based on the above several key technologies,designed a high sensitivity,wide detection range and low-cost micro thermal conductivity detector.After the micro thermal conductivity detector arranged in a gas chromatograph,the data acquired by SCM was analyzed by chromatography workstation.Finally,summarized and outlooked the entire contents of the paper. |
