Design Of The MFL Inner Inspection Of Pipeline Defect Device And A Quantitative Research On The Defect

Pipeline transportation of oil and gas transportation now occupy an important position in the oil and gas pipelines due to the erosion of long-term chemical properties of oil and gas, pipelines prone to cracks and other defects in the pipeline, once due to the oil and gas pipeline explosion caused by defects in fire and other accidents, not only on the environment pollution and cause great harm, but also bring huge economic losses and life security. Huang Wei Sinopec oil pipeline in November 22, 2013 in Qingdao, Huangdao Development Zone explosion due to leakage, resulting in 62 deaths, 136 people were injured, the direct economic losses of about 751.72 million yuan. Therefore, the oil and gas pipeline industry must conduct regular MFL testing, the risk of pipeline transportation fell to the lowest controllable range. It also has important practical significance for the study of the magnetic detection of defective drain pipe has both theoretical significance.The topic for the MFL leakage detection device reconstruct the defect structure and defect quantification of the magnetic signal a theoretical and experimental analysis. Leakage through the pipeline defects magnetic dipole magnetic field modeling analysis, while the pipeline leakage field of surface defects in magnetic charge carried ANSYS finite element modeling and simulation analysis, quantitative research pipeline defect length, width, depth and magnetic flux leakage signals the relationship between technology, pipeline leakage magnetic circuit defect detection device equivalent magnetic circuit of a mathematical model to optimize the design; proposed distribution of the work area of the sensor and the permanent magnet magnetic shielding is installed between the iron yoke to reduce the magnetic field on the interfere with the sensor, improved signal to noise ratio and the detection accuracy and simulation analysis of its effectiveness; and based on the optimization of the magnetic circuit and magnetic shielding device structure design symmetrical magnetic poles decentralized structure; topic of Hall sensor detects magnetic flux leakage signal based USB2085 data acquisition card and LabVIEW software to build a simple design defect detection experiment platform; proposes the application of a uniform bicubic B-spline surface fitting defect signal, the point raised- Newton iteration of quantitative analysis of defect signals to achieve defect geometry quantitative analysis, based on LabVIEW software environment to achieve defect leakage magnetic signal preprocessing data acquisition, and application software Matlab fitting quantify defects, lay the foundation for the visual analysis of pipeline defects.