Patent ID: 7899628
Filing Date: 2011-03-01
Classification: G01M

Abstract:
1. A method for detecting longitudinal-seam anomalies in a low frequency pipeline weld of a pipeline, the method comprising: (a) receiving magnetic flux leakage data by a computer, the magnetic flux leakage data related to one or more anomaly air gaps within a longitudinal pipeline weld; (b) displaying the magnetic flux leakage data on a display as one or more selected patterns of data representing selected signal characteristics of the pipeline weld; and (c) analyzing the magnetic flux leakage data responsive to the selected signal characteristic and selected critical flaw dimensions of the pipeline weld, the selected signal characteristics being indicators of potential longitudinal-seam anomalies in the pipeline weld and the selected critical flaw dimensions being indicators of at least a maximum length of the potential longitudinal-seam anomalies along a pattern of magnetic flux leakage data, the analyzing including: (1) determining optimal display settings on the display, the optimal display settings being responsive to different magnetic flux leakage characteristics; (2) determining whether the magnetic flux leakage data is consistent with a first predetermined anomaly level responsive to the optimal display settings to thereby define a level one anomaly candidate, the first predetermined anomaly level having first selected signal characteristics consistent with the presence of longitudinal-seam anomalies; (3) if the magnetic flux leakage data is consistent with the level one anomaly candidate, then determining if the level one anomaly candidate is consistent with a second predetermined anomaly level responsive to the optimal display settings, the second predetermined anomaly level defining a level two anomaly candidate having second selected signal characteristics different than the first selected signal characteristics and still consistent with the presence of longitudinal-seam anomalies; (4) if the level one anomaly candidate is consistent with the level two anomaly candidate, then determining if the level two anomaly candidate is consistent with a third predetermined anomaly level responsive to the optimal display settings, the third predetermined anomaly level defining a level three anomaly candidate having third selected signal characteristics different than the first and second selected signal characteristics and yet still consistent with the presence of longitudinal-seam anomalies, the third selected signal characteristics also being indicative of the presence of the selected critical flaw dimensions of a pipeline weld; (5) if the level two anomaly candidate is consistent with the third level anomaly candidate, then determining if the level three anomaly candidate is consistent with a fourth predetermined anomaly level responsive to the optimal display settings, the fourth predetermined anomaly level defining a level four anomaly candidate having fourth selected signal characteristics different than the first, second, and third selected signal characteristics and yet still consistent with the presence of longitudinal-seam anomalies; and (6) if the level three anomaly candidate is consistent with the level four anomaly candidate, then generating an output of the level four anomaly candidate to further determine if the level four anomaly candidate is consistent with a fifth predetermined anomaly level, the fifth predetermined anomaly level defining a level five anomaly candidate having fifth selected signal characteristics different from the first, second, third and fourth selected signal characteristics and yet still being indicative of one or more longitudinal-seam anomalies in the pipeline weld potentially leading to fluid leakage within the pipeline when the pipeline contains fluid therein.