| 摘要 |
<p>The present invention relates to a method for adjusting a zero point of an ultrasonic flowmeter and a method for measuring a distance between ultrasonic vibrators. In the zero point adjustment method according to the present invention, which is performed by using a flowmeter where at least a pair of ultrasonic vibrators are disposed, a first time and a second time are measured, the first time being from ultrasonic emission at an upstream side vibrator on a fluid moving path to reception at a downstream side vibrator through two reflections between the ultrasonic vibrators and the second time being from ultrasonic emission at the downstream side vibrator to reception at the upstream side vibrator through two reflections, ultrasonic emission and reception are performed respectively from the upstream side to the downstream side from the downstream side to the upstream side without any reflection process so that a third time and a fourth time are measured, and then a zero point time difference between upstream-to-downstream ultrasonic transmission and downstream-to-upstream ultrasonic emission is calculated through a computation process before accurate zero point adjustment using this value and correction value setting in a controller. According to the present invention, the value obtained in the computation step can be used for accurate measurement of the distance between the ultrasonic vibrators.</p> |
