Research Of Spectrμm Absorption Infrared Methane Sensor

With the development of coal industry, methane explosion and outburst accidents occur frequently, methane detection becomes an important subject in coal mine safety production. The main components of mine gas is methane, methane concentration, oxygen and fire source are main factors of methane explosion. Therefore, the real-time application of reliable methane concentration monitoring technology has important significance for society and economy in order to reducing the loss of state property and people life.Basing on the current situation and development status of methane detection, The thesis key research includes following contents:1) Firstly, the conventional detection methods of methane and the present home and abroad development situation of the infrared methane sensors have been summarized in this thesis. Then, the principle of infrared spectrum absorption and differential absorption technology are introduced, laying a theoretical foundation for the thesis.2) Secondly, the infrared methane sensor system using methane gas has strong absorption spectrum at 3.31μm is designed based on the principle of infrared spectrum absorption, differential absorption technology and the working mode of single optical path and dual-wavelength. The hardware design of infrared methane sensor is emphatically introduced and light source modulation technology was studied. Differential amplification circuit serves as the core of signal conditioning circuit, methane concentration information is acquired by high speed A/D chip.3) Thirdly, the methane absorption experiments have been implemented by the differential absorption infrared methane sensor. Binomial Expression fits relationship between methane concentration and voltage. The indication compared experiment, consistent experiment and stability experiment have been verified. The experiment results show the sensor system runs steadily and various technical indexes meet the requirement of project.4) Finally, Influence of coal dust with different particle size and humidity on the stability and reliability of infrared methane sensor has been researched. In addition, dustproof and waterproof technology of infrared methane sensor have been studied. The long time and continuous experiments of coal dust and humidity on infrared methane sensor have been performed respectively using self construction experiment of coal dust and humidity. The important conclusion that influence of coal dust on infrared methane sensor shows linear relationship and influence of humidity on infrared methane sensor also shows linear relationship in certain time was obtained, experimental model of influence of coal dust and humidity on infrared methane sensor was established preliminarily.