Patent ID: 6951133

Claim:
An apparatus for nondestructive testing of metallic structures comprising: (A) a housing having an opening surrounding an exterior wall of a metallic object having a longitudinal axis; said metallic object translatable, along its longitudinal axis, through the housing; and (B) a first electromagnetic acoustic transducer comprising: (1) a first plurality of substantially similar permanent magnets mounted in the housing and arranged in a first array and positioned substantially in planar radial fashion, about a first radial center, around the opening at substantially equal intervals with ends of adjacent magnets possessing opposite polarity; said first array positioned transverse to, and with the first radial center substantially colinear with, the longitudinal axis of said metallic object; each of said first plurality of substantially similar permanent magnets comprising: (a) a first end adjacent to the opening and (b) a second end substantially perpendicular to and spaced from the wall wherein the second end is notched in the plane substantially colinear with the longitudinal axis of the metallic object; and (2) a first electrically conductive wire coil mounted in the housing and positioned within an annular channel formed by the notched second ends of the first plurality of substantially similar permanent magnets.