Patent ID: 8997581
Filing Date: 2015-04-07
Classification: G01F

Abstract:
1. A flow rate measuring device comprising: a flow rate measurement part having two sides, wherein the flow rate measurement part comprises a first ultrasound transmission element/reception element on one side and a second ultrasound transmission element/reception element on the other side, with a distance L therebetween, wherein the resonance frequency of each ultrasound transmission element/reception element is a frequency of an isolated peak of group velocities of guided waves, from among a plurality of peaks of group velocities of guided waves, and wherein the semi-amplitude of a power spectrum of ultrasound excited/received by the ultrasound transmission element/reception elements is a value that does not overlap with another peak of group velocities; a flow rate computation circuit for calculating a propagation time T 1 and a propagation time T 2 , wherein the flow rate computation circuit further obtains a flow velocity of a fluid from a propagation time difference between propagation time T 1 and propagation time T 2 , the propagation time T 1 being a time in which a first guided wave, excited by being driven by the first ultrasound transmission element/reception element, propagates from upstream to downstream to the second ultrasound transmission element/reception element set apart by gap L, and the propagation time T 2 being a time in which a second guided wave, excited by being driven by the second ultrasound transmission element/reception element, propagates from downstream to upstream to the first ultrasound transmission element/reception element set apart by gap L.