Mechanical Design Of Spherical Pipeline Inner Detector

So far, the length of the oil and gas pipelines has got to more than250,000,000km in the worldwide. The total length of China’s oil and gas pipelines has reached77,000km, the pipeline length pre-get to140,000km in2016. Leak detectiontechnology is paid more concern under the influence of pipeline construction boom. Apipeline spherical detector is proposed in this paper, for the problem of tiny leaksdetection and high-precision positioning is eager to solved in the domestic andinternational pipeline transport. The detector equipped with sensors rolls with thefluid movement, collect a variety of information along the way, determine thepresence of small leaks and achieve precise positioning.The flange mechanical structure of pipe detector meets the internal spacerequirements and external environmental requirements. It is connected of two partsflange type. One part is the inner sphere, and the other is the outer shell.Corresponding to different sizes of the diameter, it simply replace the appropriatespherical shell. This structure reduces the processing cycle and improveinterchangeability. Boss structure inside the spherical detector fixed circuit boards,sensors and power module. The upper hemisphere and the lower one are fixed by theflange structure and sealed in the flat form of O-ring. It is easy to assemble and hasgood sealing performance. In the meanwhile, stress analysis related with the ballpressure resistance is operated by the nSimulationXpress. It shows that optimum wallthickness is10mm. Suppress experimental for the machining sphere gets a success.During the experiment the sphere doesn’t occur leaked, and the surface does notappear any deformation, cracks, etc. The experiment fully proves the reliability of thedesign.The stable movement of spherical detector in the pipeline is an importantprerequisite for leak detection. Hydrodynamic model of the detector under the role offluid can guide to optimize its structural design. The flow field numerical simulationresults of different radius detectors in the same pipeline show that,with the increaseof the spherical shell radius, fluid thrust and torque which the sphere suffers are alsoincreasing; the torque suffered by the ball near130mm diameter is relativelystable. The result of three-dimensional simulation verifies the correctness of thetwo-dimensional flow field simulation. Experiments in Langfang pipeline shows thatthe spherical detector move smoothly to the export in a attitude stabilization through curved pipes, inclined pipes and vertical pipes, and do not occur blocking andleakage.Mechanical structure is a carrier of the spherical detector; for complex workenvironment in the pipeline hydrodynamic analysis provide accurate numericalsimulation. Experimental results show that the mechanical structure sealingperformance, pressure resistance, and the layout of internal structure is good, andmotion posture are stable, which provide prerequisites for precise positioning of thetiny leak.