| 摘要 |
PROBLEM TO BE SOLVED: To measure an accurate flow rate by detecting a mixing of a bubble noise. SOLUTION: An apparatus for ultrasonically measuring a flow rate measures the flow rate of a fluid by using a velocity of an ultrasonic wave to be propagated from the upstream side to the downstream side/from the downstream side to the upstream side in the fluid. The apparatus detects abrupt changes in a sing-around-frequency during measurement of a flowing velocity of the wave, to thereby decide the mixture of the bubble noise. The apparatus measures the propagation time of the wave from a transmitter to a receiver prior to the measurement, controls the timing of a generation of a gate signal thereafter in the measurement, to match with the measurement time and always optimally sets the timing of the signal.
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