| 摘要 |
PURPOSE:To make the measurement of the liquid level accurate, by measuring the propagation time of ultrasonic waves through a part of a metal medium immersed in liquid whose temperature is kept constant, thereby making constant the propagation speed of the metal, whose distance is to be converted. CONSTITUTION:A wave transmitting and receiving medium 1 is made of a bent metallic pipe or the like, which is provided with both end parts 1a and 1b and a folded part 1c. The folded part 1c is immersed in a very low temperature liquid 3. Ultrasonic wave vibrators 4 and 5 are attached to the medium 1, and fixed to a cover plate 6 of a constant temperature tank 2. A transmitting instrument 7 and a receivng side measuring device 8 are connected to the vibrators 4 and 5, respectively. Ultrasonic vibration waves are imparted to one end of the medium 1. The time period of the passage of the waves in the part of the medium immersed in the liquid is computed 8, based on the phase difference between the passing time of the ultrasonic waves propagated through the medium 1 and the passing time of the ultrasonic waves propagated in one leg of the medium 1 from the other leg of the medium 1 along the liquid surface 3a. Thus the liquid level is measured. |
