Gas Pipeline With Pressure Sealing Fixture Optimization Design

With the development of society，the gas pipeline construction has reached a peak.However，with gas pipeline aging and rapid increase of urban construction and retrofit, pipelinefailure occurs frequently due to pipeline corrosion and the third party damage. Pipeline failureand leakage will cause serious environmental pollution and energy waste，especially threatenequipment and personal safety.In this paper, the techniques for repairing urban gas pipeline under the working pressurewere studied. Technique of injecting glue using fixtures was focused on, according to presentresearch status at home and abroad for gas pipeline leakage and analysis of the existing repairtechniques. Considering that PE anti-corrosion coating on gas pipelines is unlikely to peel offwithout open flame conditions and that traditional fixtures is lack of PE coating structures,cumbersome and are inconvenient for repair operation, the fixture structure was improvedbased on a mechanical analysis to make them lighter and more convenient for field operationand reduce the use of material and cost. Then the improved fixtures for defective pipes withdifferent diameters (straight pipe, tee joint, and elbow) were analyzed using the finite elementmethod. Finally a bench test and a field plugging test were conducted to verify if the PEcoating could peel off and ensure the sensitivity, effectiveness and safety of the improvedfixtures in the plugging test.With a combination of theoretical research, numerical simulation, bench test, and fieldapplication, the study tried to promote the application of the glue injection technique usingfixtures in the repair of urban gas pipelines, effictively solving the leakage of gas pipelinewith3PE coating and providing a reference for the research on related equipment of thistechnology.