Patent ID: 6925891
Filing Date: 2005-08-09
Classification: G01F

Abstract:
1. An ultrasonic flowmeter comprising: first and second ultrasonic transducers which transmit and receive ultrasonic waves, and which are placed so as to form a path for propagation of the ultrasonic waves in a flow passage for a fluid; a transmitting section which drives one of said first and second ultrasonic transducers at a resonance frequency; a first matching section which is connected to said transmitting section, and which adjusts the output impedance of said transmitting section; a receiving section which has an input impedance lower than the adjusted output impedance, and which receives the ultrasonic wave reaching the other of said first and second ultrasonic transducers; a first switching section for selectively connecting said first matching section and one of said first and second ultrasonic transducers; and a second switching section for selectively connecting said receiving section and one of said first and second ultrasonic transducers, wherein the flow volume of the fluid is measured by detecting a bidirectional-propagation time difference between the ultrasonic waves propagating in said propagation path.