Research On Encapsulation Improvement And Detection Method Of Methane Sensor

Methane gas sensor is the key perception link of the perception mine Io T, and is one of the necessary device to ensure a safe work environment in coal mines. Nowadays, catalytic combustion methane sensors are mainly and widely used in coal mines. However, it is cannot satisfy the requirement of lower power consumption with high sensitivity for perception mine Io T. In order to reduce the power consumption, this thesis has mainly studied the improvement of catalytic element(pellistor) package and methane detection method.Firstly, the paper analyzed the heat transfer mechanism of silica aerogel and the thermal loss paths for pellistor in conventional package. To solve the problem of the amount of heat lost to ambient atmosphere through pellistor traditional package, an improved package was proposed by introducing hydrophobic silica aerogel powder as thermal insulation material filled in TO metal cap. Experimental results show that the performances of pellistor encapsulated by hydrophobic silica aerogel are enhanced with power consumption decrease of approximately 30%.Secondly, on the basis of the above research results, a further study of the performance impact of pellsitor with the forming hydrophobic silica aerogel package has been taken. In this paper, the preparation technology of pellistor package which prepared by hydrophobic silica aerogel was investigated. The silica aerogel forming package was synthesized by mixing hydrophobic silica aerogel, ethanol and tetraethoxysilane at ambient drying pressure. And the factors affecting the block silica formation were analyzed and optimized. The experimental results show that pellistor can be well encapsulated with block silica and the power consumption of pellistor was decreased.In the end, a pulse detection method based on pellistor was proposed to measure methane concentration. Additional, software system was designed for testing the novel methane detection. The test result show that, novel pulse detection method can further decrease the power consumption of pellistor and the detection signal is linear with methane concentration.