TRANSIENT ELECTROMAGNETIC METHOD FOR DETECTING IRREGULARITIES ON CONDUCTIVE CONTAINERS HAVING VARIATIONS IN JACKET THICKNESS

摘要

A transient electromagnetic method for detecting irregularities on container walls by measuring wall thickness. The method utilizes a transmitting antenna and separate receiving antennas so as to form a loop-loop configuration. The transmitting antenna induces current into the container wall and the receiving antennas detect the induced current and produce received signals. The distance between the antennas and the container wall can vary, particularly where insulation is interposed therebetween. The variations in antenna distance affects the received signals. The affects are corrected by determining the maximum of the respective received signal and determining the arrival time of the maximum. The maximum and the arrival time are used to determine the thickness of the wall.