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Calibration method and device for long range guided wave inspection of piping

  • US 6,968,727 B2
  • Filed: 04/29/2003
  • Issued: 11/29/2005
  • Est. Priority Date: 04/29/2003
  • Status: Active Grant
First Claim
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1. A method of calibrating long range guided wave signals from a pipe under test consisting of the following steps:

  • first generating near a test area a first guided wave in said pipe under test by a transmitter probe and guided-wave instrumentation;

    first propagating said first guided wave along said pipe under test;

    first detecting in said pipe under test by a receiver probe and said guided-wave instrumentation first reflected signals from defects, if any;

    placing a first reference reflector on said pipe under test near said test area, but outside a dead zone for guided waves;

    generating a second guided wave in said pipe under test by said transmitter probe and said guided-wave instrumentation;

    second propagating said second guided wave along said pipe under test;

    second detecting in said pipe under test by said receiver probe and said guided-wave instrumentation second reflected signals from said first reference reflector and defect signals from said defects, if any;

    correcting for attenuation in said reflected signals and said defect signals; and

    calculating size of said defects using said first reflected signals and said second reflected signals.

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