Patent ID: 6216544
Filing Date: 2001-04-17
Classification: G01F

Abstract:
An ultrasonic flowmeter comprising:a flow path includinga flow measurement section in which a fluid flows, said flow measurement section being defined by at least one wall section, a cross-section of said flow measurement section having a shape; anda pair of ultrasonic oscillators both configured to transmit and receive from each other an ultrasonic wave having a propagation frequency, said ultrasonic wave comprising a direct wave and a reflected wave which is reflected from one of said at least one wall section resulting in a phase difference corresponding to the difference between a propagation distance of said direct wave and a propagation distance of said reflected wave, said pair of ultrasonic oscillators being separated by a distance, said pair of ultrasonic oscillators connected to at least one of said at least one wall section;a measurement section coupled to said pair of ultrasonic oscillators and configured to measure a propagation time of said ultrasonic wave which propagates between said pair of ultrasonic oscillators; anda calculation section coupled to said measurement section and configured to calculate a flow of said fluid in said flow measurement section in response to a measurement result output from said measurement section;wherein said flow path is configured to reduce an influence of the phase difference between said direct wave and said reflected wave upon said measurement result by changing at least one of said propagation frequency of said ultrasonic wave, said distance separating said pair of ultrasonic oscillators and said shape of said cross-section of said flow measurement section.