USA As Represented by Secretary of the Navy

Narendra K Batra

Kirth E Simmonds

Richard B Mignogna

A method and an apparatus are provided for measuring the thickness of a coating material using ultrasonic signals. A broad band of frequencies is transmitted by a transducer towards a layer of coating layer on a substrate and a trailing signal is received from the coating layer/substrate interface while a leading backscattered signal from a fluid/coating layer is gated out. The trailing signal is deconvolved into a set of frequencies. The resonant frequency of the coating layer is determined as the frequency with the greatest amplitude. The thickness of the material is calculated as a function of the resonant frequency of the coating layer.

Method for measuring coating thickness using ultrasonic spectral tracking

An aspect of the present invention is an apparatus for inspecting a base of a liquid filled tank for corrosion, having (a) a housing for use in the liquid filled tank; (b) a set of one or more ultrasonic transducers mounted to the housing, for directing one or more ultrasonic pulses at the base, where the ultrasonic pulses each have a frequency selected to produce a return signal from the base, and for receiving this return signal; and (c) a data capturing system for storing information from these return signals. Optional features include a second set of one or more ultrasonic transducers for directing one or more ultrasonic pulses at the liquid/gas interface at a frequency selected to produce a return signal from the liquid/gas interface, a data analysis system, a locomotive system, and a spatial location system. Another aspect of the invention is a method for inspecting a base of a liquid filled tank for corrosion, having the steps: (a) directing a broadband ultrasonic pulse at the base from an ultrasonic transducer within the tank, where the ultrasonic pulse includes a resonant frequency for the tank base over the range of expected thicknesses for the base; (b) receiving a return signal with the ultrasonic transducer; (c) performing a Fourier analysis on the return signal to generate a frequency domain signal; and (d) determining the thickness of the base from the frequency domain signal.

Method and apparatus for in situ measurements of corrosion of submerged surfaces

An aspect of the present invention is an apparatus for inspecting a base of liquid filled tank for corrosion, having (a) a housing for use in the liquid filled tank; (b) a set of one or more ultrasonic transducers mounted to the housing, for directing one or more ultrasonic pulses at the base, where the ultrasonic pulses each have a frequency selected to produce a return signal from the base, and for receiving this return signal; and (c) a data capturing system, for storing information from these return signals. Optional features include a second set of one or more ultrasonic transducers for directing one or more ultrasonic pulses at the liquid/gas interface at a frequency selected to produce a return signal from the liquid/gas interface, a data analysis system, a locomotive system, and a spatial location system. Another aspect of the invention is a method for inspecting a base of a liquid filled tank for corrosion, having the steps: (a) directing a broadband ultrasonic pulse at the base from an ultrasonic transducer within the tank, where the ultrasonic pulse includes a resonant frequency for the tank base over the range of expected thicknesses for the base; (b) receiving a return signal with the ultrasonic transducer; (c) performing a Fourier analysis on the return signal to generate a frequency domain signal; and (d) determining the thickness of the base from the frequency domain signal.

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Springfield, VA, United States of America

Narendra K Batra