Heat exchangers are devices used in the industry to transfer heat between two fluids by thermal conduction through the material of the exchanger. In the petrochemical and power generation industries, typical heat exchangers have tens or hundreds of tubes. Bobbin probes and multiplexed or nonmultiplexed array probes are used for the eddy current inspection of nonferromagnetic tubing in heat exchangers and condensers. In this paper, the ability of three different probe types (bobbin probes, nonmultiplexed array probes, and multiplexed array probes) to detect and depict volumetric and linear discontinuities is evaluated and compared. The signals obtained from the inspection of tube samples with those three probe types and the resulting data representations are measured and analyzed. The bobbin probe has a simple design that gave a good signal for long axial discontinuities and significant holes, but it is not sensitive to the orientation of some discontinuities or smaller discontinuities and doesn’t provide imagery of the discontinuity’s angular location or morphology. The nonmultiplexed probe allows for a low-resolution detection but can miss small angular extent discontinuities. The high-definition multiplexed array probe provided superior detection of circumferentially oriented discontinuities and detailed visualization of the surface.
Addepalli, S., D. Eiroa, S. Lieotrakool, A.-L. François, J. Guisset, D. Sanjaime, M. Kazarian, J. Duda, R. Roy, and P. Phillips, 2015, “Degradation Study of Heat Exchangers,” Procedia CIRP: Proceedings of the Fourth International Conference on Through-life Engineering Services, Vol. 38, pp. 137–142.
ASME, 2011, 2010 ASME Boiler & Pressure Vessel Code, with Addenda: Section V - Nondestructive Examination, American Society of Mechanical Engineers, New York, New York.
Bajula, David R., 2004, “Electromagnetic Testing of Process Tubing and Heat Exchangers,” in Nondestructive Testing Handbook, Third Edition, Vol. 5: Electromagnetic Testing, ed. Satish S. Udpa and Patrick O. Moore, American Society for Nondestructive Testing, Columbus, OH, pp. 382–385.
Cecco, V.S., G. Van Drumen, and F.L. Sharp, 1997, Advanced Manual for: Eddy Current Test Method, National Standard of Canada 0226-4587 CAN/CGSB-48.14-M86, Canadian General Standard Board, Ottawa, Ontario, Canada.
Konerza, Jonathan, 2012, “Inspection of Stainless Steel Heat Exchanger Tube with Eddy Current Array Probe,” 12th EPRI Balance-of-Plant Symposium, 6–8 August, Orlando, FL.
Krzywosz, K., and P. Lara, 2001, “Guideline for Condition Assessment and Inspection of Fossil Plant Heat Exchangers,” EPRI, Palo Alto, CA.
Stetler, Bruce, 2012, “Non-Multiplexed vs. Multiplexed Eddy Current Array Probes for Heat Exchanger Inspection,” in 2012 Annual Conference Paper Summaries CD-ROM, American Society for Nondestructive Testing, Columbus, OH.
Udpa, Satish, and Nathan Ida, 2004, “Probes for Electromagnetic Testing, Parts 1 and 2,” in Nondestructive Testing Handbook, Third Edition, Vol. 5: Electromagnetic Testing, ed. Satish S. Udpa and Patrick O. Moore, American Society for Nondestructive Testing, Columbus, OH, pp. 127–131 and pp. 148–151.
Wright, Michael, 2014, Eddy Current Array Technology, 1st ed., Eclipse Scientific Products, Waterloo, Canada.
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