Study on the Sealing Performance of Large-Diameter Monolithic Insulating Joints

With the growing demand for energy and the continuous development of oil and gas field exploitation technologies, the transportation of oil and gas through pipelines has seen extensive application and development. Insulating joints are essential anti-corrosion devices in pipeline engineering and play an irreplaceable role. As one of the weakest components in pipelines, incidents caused by the rupture of insulating joints have been frequent in recent years. This thesis focuses on large-diameter monolithic insulating joints and primarily investigates their sealing characteristics through numerical simulation methods. It establishes a scientific and rational analysis model for large-diameter monolithic insulating joints and explores the main factors affecting their sealing performance. The study examines the impact of different medium pressures and the amount of seal compression on the sealing performance of insulating joints. It is found that a U-shaped seal can form a seal under medium pressures ranging from 6MPa to 18MPa. As the medium pressure increases, the difference between contact pressure and medium pressure significantly reduces, stabilizing when the pressure exceeds 12MPa, making medium pressure no longer a major factor affecting seal performance. It is also found that the sealing effect of the U-shaped seal improves with increasing medium pressure; a compression amount of 2mm can form a good seal, and higher compression amounts can increase the equivalent stress on the seal, affecting its lifespan. This research holds significant implications for the safe operation of pipeline engineering.