Application of plastic joint expanding plugging technology for rush repair of pipelines

With respect to the rush repair and technical reform of in-service oil and gas pipelines, plastic joint expanding plugging technology is developed. This technology uses the compression expansion characteristic of the plastic PTFE joint. A dedicated cutter is used to cut off small complete pipe sections from the pipeline in the radial direction under the closed condition. The PTFE joint is installed on the hydraulic lift rod machinery and then embedded in the position where small complete pipe sections are cut off. The lift rod machinery is used to compress the PTFE joint so that the PTFE joint follows the circumferential expansion. When the joint surface is expanded to the top and bottom nicks of the pipe section, the expansion will continue and the PTFE part is embedded into the nicks to plug the pipeline to realize the plugging of pipeline. As shown from the results of application in the pressure-induced pipe technical reform in a valve chambers in the West-to-East Gas Pipeline, plastic joint expansion plugging technology can reach technical requirements by using a layer of plugging and provide better plugging effects without installation of nitrogen isolation capsule, which extremely improves the safety and operability of maintenance for in-service pipelines.