Method and apparatus for establishing and/or monitoring the filling level of a medium in a container
AssigneeEndress + Hauser GmbH + Co. KG
InventorsSascha D'Angelico, Sergej Lopatin
Life of this patent
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Abstract
The invention relates to a method and an apparatus for establishing and/or monitoring the filling level of a medium in a container and to the determination of the density of a medium in a container. It is the object of the invention to propose a method and an apparatus which permit reliable determination and/or monitoring of the filling level or the density of a medium. With reference to the apparatus according to the invention, the object is achieved by virtue of the fact that at least a first mode and a second mode of the oscillations of the oscillable unit (2) are evaluated, and the evaluated modes are used to detect a change in mass at the oscillable unit (2).
Claims38
A method for determining at least one of a filling level and a density of a medium in a container, the method comprising the steps of:
- exciting an oscillable unit to oscillate by means of an exciter oscillation;
- detecting that a predetermined filling level has been reached as soon as the oscillable unit oscillates at an oscillation frequency which exhibits a predetermined frequency change with respect to a frequency of the exciter oscillation;
- determining the density of the medium with the aid of the oscillation frequency of the oscillable unit;
- and
- evaluating at least a first mode and a second mode of the oscillations of the oscillable unit which exist while the oscillable unit is in contact with the medium to detect a change in mass at the oscillable unit.
An apparatus for determining at least one of a filling level and a density of a medium in a container, the apparatus comprising:
- an oscillable unit which is configured to be fitted to the container;
- a drive/reception unit which excites the oscillable unit to oscillate with the aid of a prescribed exciter frequency, and which receives oscillations of the oscillable unit;
- and
- a control/evaluation unit which detects that a predetermined filling level has been reached as soon as a prescribed change in frequency occurs, and which determines the density of the medium with the aid of an oscillation frequency of the oscillable unit;
- wherein the control/evaluation unit uses at least a first mode and a second mode of the oscillations of the oscillable unit which exist while the oscillable unit is in contact with the medium for the purpose of evaluation, and the control/evaluation unit detects a change in mass at the oscillable unit with the aid of the evaluated modes.
Dependencies are inferred from the claim text.