Method and apparatus for determining the amount of magnetic debris adhering to the exterior of a tube

摘要

A method and apparatus for magnetically measuring the amount and location of magnetite (Fe3O4) debris adhering to the exterior of heat exchanger tubes which can be made of Inconel. A probe containing one or more coils of electrical wire is used to traverse the interior of the subject tube. One of the probe coils is energized with direct electric current to magnetize the magnetite coating on the tube exterior as the probe traverses the tube. The thickness of the magnetized coating is deduced from measurement of the voltage generated across a second coil of wire on a probe which traverses the tube at constant velocity.