Patent ID: 7019518
Filing Date: 2006-03-28
Classification: G01B

Abstract:
1. A method for determining the thickness of a ferromagnetic material having a known conductivity and permeability comprising the steps of: (a) engaging the ferromagnetic material with an electrically isolated constant signal that is an electromagnetic signal of constant frequency and amplitude for inducing a changed signal within the ferromagnetic material, (b) generating a stepped saturation signal over a range of currents that is electrically isolated from the ferromagnetic material for engagements with the ferromagnetic material, (c) detecting by electrically isolated means the changed signal as the saturation signal is varied over the range of currents, (d) determining the relationship between the changed signal and the stepped saturation signal, and (e) evaluating the thickness of the material based upon the relationship between the charged signal and the stepped saturation signal.