Method and apparatus for detecting external cracks from within a metal tube
- Albuquerque, NM
A method and tool using a continuous electromagnetic wave from a transverse magnetic-dipole source with a coaxial electric-dipole receiver is described for the detection of external sidewall cracks and other anomalies in boiler tubes and other enclosures. The invention utilizes the concept of radar backscatter rather than eddy-currents or ultrasound, which are sometimes used in prior art crack-detection methods. A numerical study of the distribution of the fields shows that the direct transmission from the source to the receiver is reduced from that in free space. Further, if the diameter of the receiver dipole is made sufficiently small, it should be possible to detect cracks with a scattering loss of up to -40 dB in thin-walled boiler tubes.
- Research Organization:
- SANDIA CORP
- Assignee:
- Sandia Corporation (Albuquerque, NM)
- Patent Number(s):
- US 6271670
- Application Number:
- 09/246,262
- OSTI ID:
- 873919
- Country of Publication:
- United States
- Language:
- English
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