Research And Design Of CO Gas Analyzer

The environmental pollution has become the global hot topic, especially the atmospheric pollution is getting worse. To reduce the air that being polluted by noxious gases, both the industrials and auto industry are trying best to control the emission of harmful gases, which include carbon monoxide, carbon dioxide, hydrocarbon, NOX as well as particles. Naturally, the gas analyzers are developing greatly due to the detecting of harmful gases receives more and more attention.Nowadays, there are several ways to detect harmful gases efficiently, such as electrochemical type, thermal-conductivity type, catalytic combustion type, infrared spectroscopy type and so on. Owing to the technology of the thermal devices, the optical devices and the electric devices being greatly developing as the improvement of science and technology and the development of electronic technology, the infrared gas analysis technology has developed. Now the infrared gas analysis technique has being becoming the hot research point both the domestic and the international.The research object of the paper is the Non-Dispersive Infra-Red(NDIR) gas analyzer. Then, this paper did in-depth study based on the test gas of the carbon monoxide. The paper first introduces the research background of infrared gas analyzer, summarize the development history of infrared gas analyzer, compare the different types and principles of gas analyzer,and then designed and implemented the whole NDIR gas analyzer. The sensitivity and portable of the NDIR gas analyzer are significantly improved by driving the infrared source using electrical modulation mode other than pulsator modulation mode by replacing traditional IR source by the source with excellent performance in black body radiation. The embedded microcontroller is used as the core of the controlling system in the design. To ensure the accuracy and stability of the gas analyzer results, the high precision rectifier filter circuit and the AD sampling circuit is designed in the system. The various links those are necessary from the design to the implementation in the system are designed and verified, including the design of the electronic circuit, distribute gas system, optics system and so on. The gas analyzer designed in the paper is accurate and stable after improved according to a large number of experimental data being analyzed. The design of the carbon monoxide gas analyzer in the paper will provide the theoretical basis and practical guiding significance for the research of the single component or multi-component infrared gas analyzer.