Patent ID: 6025724
Filing Date: 2000-02-15
Classification: G01N

Abstract:
A method of determining a moisture content of material on a bobbin featuring a hollow core, the method comprising the steps of:(a) transmitting a microwave beam substantially through at least a portion of the bobbin, such that said microwave beam is a transmitted microwave beam;(b) receiving said transmitted microwave beam to form a received microwave beam;(c) determining a phase shift and an attenuation from said received microwave beam;(d) repeating steps (a) to (c) for at least a portion of the material on the bobbin, such that a plurality of phase shifts and a plurality of attenuations is obtained;(e) using at least one empirical factor to correct said plurality of attenuations, producing a plurality of corrected attenuations;(f) calculating a raw moisture content of the material from said corrected attenuations;(g) compensating for the presence of the core by using a previously obtained characterization of the core during a calibration step to form a plurality of corrected phase shifts;(h) determining a density of the material from said corrected phase shifts; and(i) calculating a final moisture content of the material from said density and from said raw moisture content.