| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect a liquid level, when measuring the liquid level of a vessel from the propagation time of an ultrasonic wave propagated through a liquid inside liquid level measurement piping in communication with the vessel.SOLUTION: An ultrasonic wave U is emitted to a liquid 12a inside liquid level measurement piping 12, the ultrasonic wave U reflected on the liquid 12a inside the liquid level measurement piping 12 is received, and on the basis of the relationship between frequency and sonic speed of the ultrasonic wave U propagating the liquid 12a inside the liquid level measurement piping 12, the received signal is converted to a propagation distance signal and the propagation distance signal is converted to the liquid level of a vessel 10. |
