Device for monitoring a predetermined level of a liquid in a container

摘要

For monitoring a predetermined level of a liquid in a container an ultrasonic transducer is fitted on the outer surface of the container wall at a measurement point situated at the height of the level to be monitored. The ultrasonic transducer contains a piezoelectric element which generates, when excited by an alternating voltage pulse having a given transmission frequency, an ultrasonic transmission pulse which is transferred via a diaphragm to the container wall and which converts ultrasonic vibrations transferred from the container wall to the ultrasonic transducer into electrical reception signals. So that the piezoelectric element for given dimensions can be operated in a large frequency range, and so that a good adaptation to the diaphragm is achieved, the piezoelectric element consists of a porous piezoelectric ceramic having a type 3-3 connectivity.