Patent ID: 8429966

Claim:
A capacitive fill level sensor, comprising: two electrodes having a plastic sheathing; a capacitance measuring device for detecting an electrical capacitance between the electrodes; an estimator device for estimating a fill level of a liquid between the electrodes based on the detected electrical capacitance and different dielectric constants for sections of the plastic sheathing in the liquid and outside of the liquid; and a compensation device for compensating for a drift of the detected electrical capacitance due to a change in the dielectric constant of a section of the plastic sheathing when this section dries out after a drop in the fill level, wherein the plastic sheathing in the liquid is impregnated with the liquid and the compensation device includes: a high-pass filter for determining high-frequency changes in the electrical capacitance; an accumulator for accumulating the high-frequency changes in the electrical capacitance to form an accumulation value; a damping element for periodic damping of the accumulation value at a damping rate; and an adder which is connected to the capacitance measuring device and to the accumulator for compensating for the detected electrical capacitance using the accumulation value.