Evaluating fill-level of container, using mechanical vibration system with piezoelectric elements

摘要

The filling level evaluation involves a receiver converter which receives the vibrations of the mechanical vibration system and converts this into an electric output signal. At least two identical stacks (14,15) are prepared with piezo-electric elements (16). A tension bolt (5) is coupled with its end lying opposite the diaphragm (4) at the top side of the stacks and decouples the underside of the stacks from the diaphragm. Oscillating rods (2,3) are excited by the application of an AC voltage at the excitation converter of the two stacks. The individual output signals of the receiver converter are combined. With an in-phase vibration of the oscillating rods, the complete output signal assumes approximately a zero value, and with an antiphase vibration of the oscillating rods, assumes a value, differing from zero.