| 摘要 |
PROBLEM TO BE SOLVED: To accurately measure a flow rate by eliminating a resonance phenomenon due to a reverberation of an ultrasonic vibrator. SOLUTION: The ultrasonic flowmeter comprises a drive means 23 for driving a first ultrasonic vibrator 21 and a second ultrasonic vibrator 22 provided at an upstream and a downstream of a fluid pipeline 20 to receive and oscillate an ultrasonic signal, a phase deciding means 25 for deciding a driving phase of the means 23, and a counting means 24 for counting number of times of transmitting an ultrasonic wave between both the vibrators. The means 25 variably sets a driving phase according to a counted value of the means 24. Thus, the driving phases of adjacent oscillating drives of both the vibrators 21, 22 are changed by the variable set of the phase, a resonance phenomenon due to reverberations of both the vibrators is eliminated, and accurate flow rates can be measured.
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