| 摘要 |
PROBLEM TO BE SOLVED: To easily diagnose an adverse effect of an ultrasonic flowmeter on measuring accuracy resulting from a sound reverberation state in particular of a wave sound environment while setting the ultrasonic flowmeter to a measuring point as it is.SOLUTION: A sampling period in a normal mode of an ultrasonic flowmeter 13 of a diagnostic object is defined as an actual sampling period T0 and a sampling period of a long period determined in advance to be used in a diagnostic mode is defined as a reference sampling period T1. The reference sampling period T1 is determined as a time being sufficiently longer than a time which is assumed to be a time required to attenuate sound reverberation. A propagation time difference &Dgr;t(T0) in the actual sampling period T0 and a propagation time difference &Dgr;t(T1) in the reference sampling period T1 are acquired as a measuring characteristic of the ultrasonic flowmeter 13, and in the case of being |&Dgr;t(T1)-&Dgr;t(T0)|≥&Dgr;t_th, it is determined that there is effect of the sound reverberation. As the measuring characteristic, a measuring flow amount, a propagation time inverse number difference, a measuring flow rate, or the like can be adopted in addition to the propagation time difference. |
