Infrared Thermal Image Detection Micro Leakage Of Liquid Lmmonia Lressure Lipeline Lesearch In Low Lemperature

With the improvement of people’s living standard, people to the growing demand for fruits, vegetables, meat, according to statistics, our country residents per capita daily intake of fruits and vegetables is 1.027 kg, after a scientific calculation, China’s annual total consumption of fruits and vegetables, about 4.873 tonnes, while people of quality products requirements are increasingly stringent. Cold storage can guarantee the supply of fruit, vegetables, meat and its freshness, as a result of the need, the number of cold storage in our country is increasing day by day. Most of the cold storage enterprises to use the refrigerant liquid ammonia, ammonia is a toxic substance. It also has flammable, explosive, belongs to the 2.3 toxic substances. Liquid ammonia leakage after the formation of ammonia accumulation in the air can make human and animal poisoning and explosion limit concentration is reached in case of fire may cause an explosion that could have serious impact on social security. Involved in ammonia refrigeration enterprises to use liquid ammonia pipeline leak serious, due to economic and safety, low temperature liquid ammonia pressure pipeline usually wrapped a layer of insulation materials, for cold insulation layer. Because of the cold layer, people cannot directly observe the liquid ammonia pipeline, increasing the difficulty of examination. Various detection methods such as ultrasonic testing, X-ray testing, acoustic emission testing were due to various limitations for the package protection layer of cold liquid ammonia pressure pipeline detection, for security layer of cold liquid ammonia pressure pipeline, there is no a safe, reliable, convenient detection method. In this paper, we study using infrared thermal imaging technology of cryogenic liquid ammonia pressure pipeline micro leak detection with the characteristics of safety, convenience, rapidity, macro; but it also has some limitations, since many factors influence the results of the examination, test results of partial to qualitative, non quantitative.This paper proposed using infrared thermography detection instrument of low temperature ammonia pressure pipeline detection scheme and method. Through the detection of ammonia refrigeration entity enterprise of low temperature ammonia pressure pipeline, summed up three kinds of cold insulation layer temperature anomalies hazard phenomenon. In each type, a typical hidden danger case is selected and the data analysis is carried out. Through the calculation of the cold layer thickness, thermal conductivity, frost layer shape analysis, and the internal density analysis of the hidden danger case, the point of the cold source of the heat preservation layer is analyzed. Finally by using the tools of destruction insulation layer, remove the cold insulation materials, ammonia concentration detection of hidden instance using ammonia concentration detector, ammonia concentration values can be obtained, conclusion for the analysis of leak verification, and draw a conclusion. Through the analysis and verification can be concluded, in particular to the observation of low temperature ammonia pressure insulation of pipeline for cold surface layer thermogram features and frost on the surface morphology and internal density distribution law to judge the security layer of cold of the existence of the internal liquid ammonia micro leakage.