| 摘要 |
PROBLEM TO BE SOLVED: To increase measurement precision in a device for measuring the flow velocity and/or flowrate of fluid, such as air, gas, and water, by utilizing ultrasonic waves. SOLUTION: Sound wave transmission/reception means 21, 22 fix a piezoelectric vibrator 35 onto the inner surface of cases 36, 40 and incorporate a charge detection circuit used as an electric signal conversion means at a position adjacent to the piezoelectric vibrator 35 inside the cases 36, 40. As a result, strength to noise from the outside can be increased by adjacently incorporating the piezoelectric vibrator 35 and an electric circuit into the cases 36, 40, the distance of a signal line can be shortened, thus achieving stable, precise flow velocity and flowrate measurement that is hardly affected by a change in characteristics caused by a change with time and a change in temperature. COPYRIGHT: (C)2005,JPO&NCIPI
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