A method for judging the signal of the inner detection line of the three-axis magnetic flux leakage in a pipeline depression

Abstract

The invention provides a method for determining pipeline recesses through triaxial magnetic leakage internal detection line signals. The method uses four three-dimensional hall sensors to record three magnetic leakage signals with independent axial directions, analyzes component characteristics of magnetic leakage in three directions at pipeline defects through a specialized?magnetic leakage data read tool, and determines types of the defects as well as depth, length and width information of the defects. If the following conditions are met, recesses can be determined to exist in the pipeline: (1) an amplitude changing of an axial signal is less than or equal to 5 mt; (2) a radial signal is a bidirectional pulse wave, a height amplitude of the signal?is more than or equal to 20 mt and a continuously changed length of the signal is more than 10 mm; and (3) an amplitude changing of a transverse signal is less than or equal to 5 mt. A relationship between the defect sizes and the magnetic leakage signals is that a defect depth d (mm) is in an exponential relationship with the height amplitude h (mt) of the radial signal, that is, d=18.82*e^0.001h. The method is simple and reliable to determine recess signals of the internal detection.

Description

technical field [0001] The invention relates to a method for judging signals of internal detection lines of three-axis magnetic flux leakage in concave pipelines. It relates to the technical fields of measuring magnetic variables and pipeline systems. Background technique [0002] At present, the detection and judgment of pipeline sag mainly adopts geometric internal detectors. The detectors are loaded with multiple robotic arms. If the pipeline is deformed, the robotic arms will automatically expand and contract. At the same time, the sensor on the robotic arm will send a signal, enter the data storage system, and use professional deformation analysis. The software performs data analysis to obtain the geometric deformation size and position on the pipeline. However, this method can only find sags larger than 2% of the pipe diameter. During the actual operation of the pipeline, the threat degree of the sag is determined or the existing domestic and foreign sag repair judgme...

AI Technical Summary

Problems solved by technology

Specifically, the following technical features are disclosed: use four three-way Hall sensors to record the magnetic flux leakage signals in three independent axes, analyze the characteristics of the magnetic flux leakage components in the three directions through a special magnetic flux leakage data reading tool, and judge the defect. type and the depth, length, and width of the defect, but no criterion for judging the dent

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