Filling level measuring device and method for the non-contact determination of the filling level of a filling product in a receptacle

#The present invention relates in general to a method for the non-contact determination of an overfilling of a receptacle filled with a filling product, wherein an envelope curve is generated from echo signals reflected on a filling product surface. Moreover, the present invention relates to an evaluation arrangement for realizing a method of this kind, and a filling level measuring device equipped with an evaluation arrangement of this kind.

#Filling level measuring devices of the kind of interest here, work in particular according to the so-called pulse echo principle and scan a reflected echo signal.

#Filling level measuring devices working on the pulse echo principle and scanning a reflected echo signal, generate from the scanned echo signal a series of data as to each echo in the echo image or the so-called envelope curve. Generating an envelope curve from echo signals is sufficiently known and, accordingly, further explanations as to this technology are not required here (cf., for example, German Patent DE 44 07 369 C2; M. Scholnik “Introduction to Radar Systems”, 2nd edition, 1980, McGraw-Hill; Peter Devine “Radar level measurement—the user's guide”, VEGA Controls Ltd., 2000, ISBN 0-9538920-0-X).

#For the further explanation and the better understanding, several embodiments of the present invention are described in more detail in the following with reference to the attached drawings. Therein show:

#FIG. 1 shows an extremely schematic cross-sectional view of a receptacle filled with a filling product and of a filling level measuring device mounted in the top zone of the receptacle;

#FIG. 2 shows a schematic representation of an exemplary embodiment of a filling level measuring device according to the present invention;

#FIG. 1 shows a filling level measuring device 1 is mounted in the top zone of a receptacle 5. Within receptacle 5, a filling product 6, bulk material or liquid, is present forming a filling product surface 7.

#The filling level measuring device 1 mounted in receptacle 5 comprises a housing 2 and a horn antenna 3. Via a cable 4, in particular a so-called 4-20 mA two-wire loop, the filling level measuring device is connected to a power supply unit and communication unit (not shown here).

#FIG. 2 illustrates the filling level measuring device 1 having an evaluation arrangement 10, a transmitting arrangement 11 and a receiving arrangement 12. With transmitting arrangement 11, short radar pulses in the microwave range are emitted via horn antenna 3 in the direction of the filling product surface 7. These signals are reflected on the filling product surface 7 and are received via the same antenna 3. In the receiving arrangement 12, these signals are further processed according to prior art, and are evaluated in the evaluation arrangement 10. For this purpose, an envelope curve is generated from the individual echo signals in a conventional manner. This envelope curve is then in turn closer examined using mathematical methods, in particular so as it is illustrated in the following flow charts.