| 摘要 |
PROBLEM TO BE SOLVED: To provide an ultrasonic flowmeter of high trackability, even under intense flow fluctuation conditions, and moreover, which is reduced in electric power consumption. SOLUTION: Although the propagation time of ultrasonic waves propagating between the first oscillator 2 and the second oscillator 3 is measured by a measuring control means 4 and the measuring means 4 is operated in synchronism with synchronous clocks, supplied from a low-speed quartz oscillation circuit 15 and a high-speed CR oscillation circuit 16, the flowmeter is operated synchronized with the high-speed clock supplied from the high-speed CR oscillation circuit 16, only in the last portion of the propagation time measurement, and is operated in synchronism with the low-speed clock supplied from the quartz oscillation circuit 15, at other times. The operation time of the high-speed clock, consuming high electric power, is thereby restrained to be a minimum, and a sampling interval can be set short, flow measurement capable of tracking flow changes with high trackability becomes possible. COPYRIGHT: (C)2008,JPO&INPIT
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