| 摘要 |
PURPOSE:To remotely measure the sonic velocity of an object to be measured always present at high temp. and the change thereof with high accuracy, by measuring the phase speed and group speed in the ultrasonic wave used either one of ultrasonic wave guides and performing operation on the basis of the measured values according to a specific formula. CONSTITUTION:A pair of ultrasonic wave guides 1, 2 formed the same are opposed to each other so as to provide a definite distance therebetween and a medium to be measured is interposed between the mutual other end parts of the wave guides 1, 2 and, thereafter, the phase speed Vp and group speed Vg in the ultrasonic wave used in either one of the wave guides 1, 2 are measured. Next, almost simultaneously with measurement, the time before ultrasonic waves are propagated through the wave guides 1, 2 from one end parts thereof to the other end parts thereof and the ultrasonic waves leaked from the wave guides 1, 2 are received at one-end parts of the other wave guides 1, 2 at first through the medium to be measured and the time before the ultrasonic waves further leaked in the medium to be measured from the other wave guides 1, 2 reciprocally propagate between one wave guides 1, 2 to be received are measured to calculate the difference DELTAt between both times and, by performing an operation on the basis of these measured values according to formula, the sonic velocity V of the medium to be measured can be specified.
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