| 摘要 |
PROBLEM TO BE SOLVED: To provide a flow-velocity measuring device, wherein all conditions of less dissipation power, high measuring accuracy and especially the capability of highly accurate flow-velocity measurement even in the case of low flow velocity are provided, by using an ultrasonic transceiver characterized by a small shape, high wave transmitting and receiving sensitivity, less frequency dependency and less characteristic change caused by the fluctuation of temperature and loads. SOLUTION: A laminated piezoelectric element 1, which is constituted by laminating a plurality of piezoelectric plates, is used. A sound matching layer is formed on the sound emitting surface, which is one surface of the piezoelectric element. An ultrasonic wave transceiver, which can effectively converts a driving voltage into an emitted ultrasonic wave 5, is used. The element is driven by a plurality of the voltage, whose frequency is lower than a resonance frequency, and the ultrasonic wave is emitted into fluid. The propagating time of the ultrasonic wave through the specified propagating path is measured. Thus, the flow velocity of the fluid is measured. |
