公开(公告)号：EP1735612A4

公开(公告)日：2009-06-10

申请号：EP05732756

申请日：2005-03-28

申请人： TDW DELAWARE INC

发明人： VEACH WILLIAM D ,  LLOYD TYLER S ,  LUDLOW JED C

IPC分类号： G01N27/72 ,  F16L55/26 ,  G01N27/82 ,  G01N27/87 ,  G01N27/90 ,  G01R33/12

CPC分类号： G01N27/87 ,  F16L55/26 ,  G01N27/902

摘要： An instrument pig and method of operation thereof for determining the characteristics of a ferromagnetic pipeline through which it passes, including a pig body, first and second coaxial circumferential, spaced apart magnets of opposed polarities supported to the pig body and providing substantially complete magnetic saturation of an area of the pipeline between the magnets, first instruments between the magnets arranged to generate signals that are responsive to flux leakage providing first information as to anomalies in the pipeline interior and/or exterior surfaces, second instruments supported by the pig body between the magnets and arranged to generate signals that are responsive to eddy currents induced in the pipeline interior surface providing second information as to anomalies in the pipeline interior surface, signal processing circuitry combining the first and second signals and wherein the second instruments are energized only in response to signals generated by the signal processing circuitry.