| 摘要 |
<P>PROBLEM TO BE SOLVED: To accomplish a high-accuracy ultrasonic flowmeter by preventing measuring accuracy from being deteriorated by solid propagation of vibration of an ultrasonic vibrator during transmission. <P>SOLUTION: An ultrasonic flowmeter comprises: a measuring channel 1 in which a fluid to be measured flows; a pair of ultrasonic vibrators 2 and 7 capable of transmitting/receiving ultrasonic waves; detection means which detects just a predetermined number of zero-cross points in a reception waveform generated by ultrasonic wave signals transmitted from the ultrasonic vibrator 2, propagated in the fluid to be measured, and received by the ultrasonic vibrator 7; a propagation time measuring section 5 which measures a propagation time of ultrasonic waves to each of the detected zero-cross points; propagation time selection means 9 which selects a value to be used for arithmetically operating a flow rate from among values measured by the propagation time measuring section 5; and a control section 4 which determines the flow rate of the fluid filling a gap between the ultrasonic vibrators from the selected propagation time through arithmetic operation. <P>COPYRIGHT: (C)2013,JPO&INPIT |
