| 摘要 |
<p>A method and system for performing in-line measurement of stresses in pipeline walls 110 by continuous Barkhausen method comprises an inspection pig 100 including permanent or DC electromagnets 132, 134 for generating a magnetic field that moves with the inspection pig through a pipeline 110, inductive or other types of magnetic field sensors 142 for reading Barkhausen noise signals generated by the moving magnetic field, and associated instrumentation for amplifying 412, filtering 414, detecting 416 and storing 420 the Barkhausen noise signals. The size of the sensors may be selected to match the size of defects being investigated. By comparing trending data over time to determine changes in Barkhausen noise levels, greater detection sensitivity may be achieved. The method may be particularly advantageous for use in inspection pigs that also use magnetic flux leakage to determine pipeline defects, since the magnetic flux leakage method also use permanent or DC electromagnets.</p> |
