ULTRASONIC FILLING-LEVEL MEASURING APPARATUS WITH MAXIMUM LEVEL RECOGNITION

摘要

An apparatus for detecting a filling level for a liquid in a container (1) has an ultrasonic transmitter (7) for transmitting ultrasonic signals into the liquid and an ultrasonic receiver (7) for receiving ultrasonic signals reflected at least from a surface (2) of the liquid. At least one principal ultrasonic reflector (6), in the form of a solid, is provided which is arranged in the region of a principal sound cone for the ultrasonic signals inside the container (1) at a level which corresponds essentially to a prescribed maximum level (2) for the liquid in the container (1). When filling the container (1) with the liquid, the ultrasonic signals are first of all reflected with changing intensity and direction at the liquid surface disrupted by the flow movement, which results in ultrasonic echoes which are difficult to identify and imprecise. As soon as the principal ultrasonic reflector (6) is immersed completely in the liquid, however, a stable, essentially constant ultrasonic echo is produced. This echo makes it possible to establish that the filling level of the liquid has reached at least the level of the principal ultrasonic reflector (6).