The Use of Time-Reversal Technology for Level Measurement in Liquid Tanks

One of the most widely spread measuring tasks in chemistry or food technology is the continuous determination of fill levels in liquid tanks. The aim of this paper is to present a new contactless and noninvasive measuring method based on ultrasonic time-reversal and correlation techniques. The novel method enables asserted fill levels to be identified and small deviations of them to be calculated even if the direct path from the sensor to the liquid surface is obstructed. This article will present the structure and principle of the measuring system as well as the procedure of signal processing. A simulative approach is used to demonstrate the excitation of a virtual sound source in the liquid and to show both the advantages and limits of the new technique. In addition a simplified model is developed where the solutions of the simulations are applied to.