Study On Plugging Capsule Of The Long-distance Refined Oil Transportation Pipeline

With the development of the online pipeline replacement to the higher pressure, the shorter time operation and the defect of no mechanical incision, the occluder which is a key tool used in the sealing process, is required to apply in a variety of work conditions with longer service life and simpler design, etc. At present, the baffle bag type plugging and the leather bowl type plugging are often used to repair the pipeline in domestic and abroad. Both the baffle bag type plugging and the leather bowl type plugging plug need insert the holes and will leave the flange and other components when the sealing operation is completed, which may lead to the hidden danger of the incision and the decrease in the service life of the pipeline. This is the starting point of this paper, putting forward a kind of pipeline plugging capsule which can self-relief and leave no mechanical incision on the pipe wall.By studying and analyzing the working principle and material properties of the plugging capsule, the structure and material of the plugging capsule are determined. By the uniaxial tensile test on the rubber material, the shape and the size of the capsule are calculated according to the tensile test data and the force analysis of the capsule. The MATLAB software is uesd to match the curve of super elastic material and obtain the simulation parameters of rubber materials. The nonlinear finite element analysis method is used to simulate the sealing contact between the diameter phi 530mm rubber capsule and the diameter of phi 610mm pipeline, which analyze the difference of sealing ability under the broken pipe situation between the single rubber, two rubber-one cloth structure and three rubber-two cloth structure to optimize the structure of the capsule. In the process of structure design about rubber capsule, two kinds of schemes are put forward to viewing of the shortcomings of the single layer rubber. Through the research and simulation analysis, a new type of rubber-skeleton composite material is identified.The analysis shows that the structure of the pure rubber can be expanded to the specified length to meet the friction force, but the stress concentration phenomenon exists in the end face which is easier to be damaged. In the structure of the two rubber-one cloth structure, the existence of the skeleton material reduces the expansion of the end face, but the strength of the framework and rubber are not enough and easier to be broken. In the structure of three rubber-two cloth structure, the skeleton material and the capsule all can meet the strength requirement. The simulation results show that the sealing can be realized under sealing pressure difference of 0.05Mpa and the residual medium pressure of the 0.5Mpa.