Bubble generator for use in doppler ultrasonic flowmeter and doppler ultrasonic flowmeter

摘要

A bubble generator to bring out performance of a Doppler ultrasonic flowmeter to the maximum extent is provided. The bubble generator is provided with a bubble generation member generating bubbles suitable for a predetermined frequency of an ultrasonic pulse emitted into a fluid to be measured and feeding the bubbles into the fluid pipe, and a uniform dispersion member dispersing the bubbles fed uniformly in the pipe, the bubble generator is installed on an upstream side of the fluid pipe with respect to an ultrasonic transducer. The bubble generation member has a Venturi tube, and the uniform dispersion member has a negative pressure generating device, in which the fluid to be measured drawn out by the uniform dispersion member from inside the fluid pipe is returned into the fluid pipe together with the bubbles fed into the fluid pipe via the Venturi tube.