Flow-rate measurement method and ultrasonic flowmeter

Application Number: 00126996
Application Date: 1995.10.19
Publication Number: 1295235
Publication Date: 2001.05.16
Priority Information: 1994/10/19 JP 253414/94
International: G01F1/66
Applicant(s) Name: Matsushita Electric Industrial Co., Ltd.
Address:
Inventor(s) Name: Nagaoka Kofu;Nawa Motoyuki;Oji Kenzo
Patent Agency Code: 72001
Patent Agent: zhang zhicheng
Abstract An ultrasonic flow meter includes a conduit (2) through which a fluid flows, an ultrasonic generator (6), a receiver (8) for receving ultrasonic waves on the upstream or downstream side of the generator, a time counter (32) for determining the propagation time of the ultrasonic wave, a flow rate calculator (24) for calculating the flow rate from the propagation time, and a timing controller (26). The timing controller (26) sets a delay time corresponding to the flow rate measured from the relation between a flow rate which is set in advance, and the measured delay time. After the passage of this delay time the ultrasonic wave is emitted from the generator (6) on the basis of a driving signal outputted from a trigger section (14) and the flow rate is determined. Since the flow rate is thus measured with the delay time suitable for the flow rate, the flow rate is correctly determined, and power consumption is reduced.