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Development of an Electromagnetic Acoustic Transducer for Inspecting the Wall Thickness of Offshore Risers from the Inside

  • W. H. van den Berg
  • M. H. Horns
  • A. B. M. Hoff
Part of the Acoustical Imaging book series (ACIM, volume 15)

Abstract

The design requirements for an electromagnetic acoustic transducer to determine remaining wall thickness of offshore gas risers from the inside are presented, together with the results of evaluation of a prototype. A specially designed configuration of high-energy-density permanent magnets, the choice of dedicated emitter/receiver coils and impedance matching between coils and electronics have resulted in optimum ultrasonic performance. Aspects related to implementation in an inspection vehicle, such as mechanical protection and negotiation of local obstructions inside a riser pipe, have received special attention and will be discussed.

Keywords

Magnet Pole Pipe Wall Receiver Coil Test Loop Local Obstruction 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Alers, G.A., 1981, Application of electromagnetic acoustic transducers (EMATs), Proceedings of the 26th National SAMPE Symposium, 28–30 April 1981, pp. 34–44.Google Scholar
  2. Beissner, R.E., 1976, Electromagnetic acoustic transducers, a survey of the state of the art, South-West Research Institute, San Antonio, Texas, NTIAC-76–1.Google Scholar
  3. Dobbs, E.R., 1973, Electromagnetic generation of ultrasonic waves, in: “Physical acoustics; principles and methods”, Vol. 10, W.P. Mason and R.N. Thurston, eds., Academic press, New York, Chapter 10, p. 127.Google Scholar
  4. Hammond, P., 1962, The calculation of the magnetic field of rotating machines, part 3. — Eddy currents induced in a solid slab by a circular current loop, The Institution of Electrical Engineers, Monograph No. 514S.Google Scholar
  5. Maxfield, B.W. and Fortunko, C.M., 1983, The design and use of electromagnetic acoustic wave transducers (EMATs), Materials Evaluation, 41: 1399.Google Scholar

Copyright information

© Plenum Press, New York 1987

Authors and Affiliations

  • W. H. van den Berg
    • 1
  • M. H. Horns
    • 1
  • A. B. M. Hoff
    • 1
  1. 1.Koninklijke/Shell-LaboratoriumAmsterdam (Shell Research B.V.)AmsterdamThe Netherlands

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