Researching And Realizing The Instrument Of Gas Detecting With Non-Dispersive Infrared Measurement

The methane that is seen to a chemical material and a flammable gas can be found in lots of areas in which we are living and working. Now the leakage accident about methane have increased along with the development of the petroleum & gas industry in the world. At present, the methane detection equipments in our country have some disadvantage, such as the small detection area, slow reaction, easy aging and invalidation, regular adjusting, a big body, high cost and so on. The equipment don't meet people's requirement of detecting consistency of methane.In this paper, the main component of mine gas methane is used as a research sample. A gas detecting system is achieved using non-dispersive infrared techniques which are based on the fact that many gases have unique infrared absorption signatures in the specifically region. The system has the advantages of fast responding speed, freedom from inflammation and explosion, large dynamic range and freedom from poisoning, and the detecting segment can be placed in the flammable, explosive, poisonous places that people can't come in. Thus the concentration of methane can be remote real-time detected, and the system will give an alarm to people when it is dangerous, so the explosive accident caused by gas in mine can be avoided.The article expatiate on the infrared absorption theory, the basic theory of infrared detection of methane and the structure and soft flow of the methane detection instrument of infrared. The error of system is analyzed in this paper. The gas detecting system consists of the following: infrared light source,thin-film filter,and infrared detector which is associated electronics. Design a detect method based on one wavelength through two ray channel. Analyze how to use microprocessor control unit achieve collection,display and transmission.The results of the measurement using the gas detecting system display that the system is stable.The research of the paper is useful for the design of else gas monitoring such as carbon monoxide, carbon dioxide and sulfur dioxide.