US 11,774,409 B2
Electromagnetic acoustic transducer (EMAT) for corrosion mapping
Phillip D. Bondurant, Covington, WA (US); Anthony Mactutis, Auburn, WA (US); and Richard Lyle Dougherty, Tacoma, WA (US)
Assigned to QUEST INTEGRATED, LLC, Kent, WA (US)
Filed by QUEST INTEGRATED, LLC, Kent, WA (US)
Filed on Dec. 7, 2021, as Appl. No. 17/544,520.
Application 17/544,520 is a continuation of application No. 16/490,479, granted, now 11,209,401, previously published as PCT/US2018/020638, filed on Mar. 2, 2018.
Claims priority of provisional application 62/466,264, filed on Mar. 2, 2017.
Prior Publication US 2022/0137004 A1, May 5, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. G01N 29/24 (2006.01); G01N 29/04 (2006.01)
CPC G01N 29/2412 (2013.01) [G01N 29/043 (2013.01); G01N 2291/0258 (2013.01)] 27 Claims
OG exemplary drawing
 
1. An apparatus for detecting or measuring corrosion or erosion in an object, comprising:
an electromagnetic acoustic transducer (EMAT) having:
a ferromagnetic core;
a plurality of permanent magnets arranged peripherally around the ferromagnetic core and configured to produce a magnetic field through the ferromagnetic core; and
a coil configured between the ferromagnetic core and the object,
wherein the current in the coil is generated by a series of voltage pulses, and wherein a leading voltage pulse or a trailing voltage pulse in the series are shorter than the pulses in the middle of the series, and
wherein the current in the coil is about zero at an ending edge of the trailing voltage pulse.