Patent ID: 8176783
Filing Date: 2012-05-15
Classification: G01N

Abstract:
1. An apparatus for non-contact characterization of a fluid in a container or a pipe, said container or said pipe having a wall having an outer surface, comprising in combination: an air-coupled transmitting transducer disposed outside of said container or said pipe for generating ultrasonic waves approximately perpendicular to the outer surface of the wall at a chosen first distance therefrom; a sweep generator for exciting said air-coupled transmitting transducer at chosen frequencies in a selected frequency range, whereby resonant vibrations are generated in the fluid; an air-coupled receiving transducer disposed in any configuration on the other side of said container or said pipe from said transmitting transducer at a second chosen distance from the outer surface of the wall, for receiving said resonant vibrations emitted by said fluid and perpendicular to the outer surface of the wall, said receiving transducer producing an electrical signal in response to the ultrasonic waves received thereby; a narrow-band tracking filter for receiving the electrical signal from said receiving transducer at the chosen frequencies in the selected frequency range and for generating a noise-filtered signal therefrom; a signal processor for receiving the noise-filtered signal from said narrow-band tracking filter and producing a signal containing simultaneous amplitude and phase information from the ultrasonic waves in the frequency domain; and circuitry for receiving the signal from said signal processor in the frequency domain and transforming the signal into the time domain by Fast Fourier Transform.