Application Research On Injecting Fixture Gas Pipeline With Pressure

At present, the construction of gas pipeline has made great achievements, with some important lines gradually completed, such as the Shanxi-Beijing line, Yagang line, Sheninglan,West-East natural gas transmission, the shan xi-bei jing second-line, JiNing link lines and zhong wu lines, and so on. which relieve China’s energy shortage. However with continuous running of gas transmission pipeline, pipeline itself will be damaged because of various factors inside and outside, especially in general mountainous areas due to poor geological conditions, especially in stonework section, anti-corrosion insulations are easily damaged and aging in the running process, sometimes man-made destruction and modification will result in gas transmission pipeline corrosion and perforation, even welding quality may cause gas leak,which endanger gas production activities in the upstream and downstream areas and social stability.so, It is urgent to develop a well-constructed, economic and practical, safe and reliable pressure injecting fixture to meet the requirement of constant gas pipeline transmission First through a large number of data collection, then discuss the theory many times, then make an overall design for gas pipeline injecting fixture, with repeated simulation experiment and constant improvement and the most suitable solution adjustment, we finally developed a natural gas pipeline with pressure injecting fixture which is mainly composed of fixture with sealed cavity, pressure relief sealing system, injection system. The on-line blockage is divided into four stages: fixture assembly, fixture installation, injection operation, steel-cover welding operation. The new method is applicable to emergent rescue work: the main gas pipe and branches, main line’s cracks and perforation leakage accident(as long as the deformation of the pipeline is not serious.) it can realize plugging under pressure(0 ~ 4.5 MPa) with non-stop natural gas transmission.The economic benefits brought by the application of pressure injecting fixture for natural gas pipeline with are obvious:(1)If you do not use online leak sealing fixture, but to close the upstream or downstream valves, then release and substitute the gas and then replace the line,which, on the one hand, will waste the vent gas between the two valve chamber, and also creates unnecessary pollution; on the other hand, such operation takes longer and cause a lot of negative effects on downstream users. Its direct and indirect losses will be caused.(2) If we use traditional plugging technology under pressure, we need to keep protective measures for leak to guarantee seal tee, by-pass tee, balance pipe nipple welding safety, and meanwhile toprefabricate by-pass pipe and perform further opening operation, plugging operation,substitution operation, and restore the normal operation of pipeline. To complete such an operation need about a week’s time, and the investment is large, so is the cost of manpower.(3)If we use online leak sealing fixture, it would be faster and consume less resources and manpower, which will greatly reduce the accident loss and ensure the security of downstream domestic gas and industrial production, and also will avoid the negative influence on downstream users for being cut off so long.