| 摘要 |
Process for locating the level of separation or interface, the position of which is unknown, between a liquid and another fluid, liquid or gas. The process consists in applying an ultrasound wave to the interface by means of a probe located at a reference point in the liquid, reflecting the wave onto the interface and sensing the reflected wave, preferably at the same point of reference, in order to define a measurement path; a time is then measured representing the time taken by the wave to traverse this path. Several reflectors are arranged at different known distances from the reference point. The time of the measurement path is used to select a reference reflector being the one among the reflectors which is the closest to the interface, at a distance from the emitter less than that from the interface. The length of the measurement path is deduced by using the time of the measurement path and the time of the reference path of the wave on the reference reflector. The invention is characterized in that there are at least two reflectors in the liquid medium, between the probe and the surface, and that the measurement of the speed of sound between the two last reflectors is used to determine the tendancy or the gradient so as to extrapolate with more precision the height of the liquid above the last reflector.
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