Patent ID: 9448248
Filing Date: 2016-09-20
CPC Classification: G01F,G01N

Claim Text:
1. A method for detecting a fluid surface ( 10 ), comprising the following steps: providing at least one probe ( moving the probe ( 2 ) into or out of a fluid ( 4 ); charging the probe ( applying a periodic third electric signal (S 3 ) to one or more electrically conductive regions separate from the probe ( 2 ) simultaneously with applying the first electric signal (S 1 ) to the probe ( 2 ), wherein the third electric signal (S 3 ) is based on the first electric signal (S 1 ); at least partially discharging the probe ( 2 ) so as to obtain a discharging current; detecting a second electric signal (S 2 ) based on the discharging current; analyzing the second electric signal (S 2 ) or a signal derived from the second electric signal (S 2 ) with respect to the capacitance (C) of the probe ( 2 ); and identifying the fluid surface ( 10 ) of the fluid ( 4 ) based on a change of the capacitance (C) of the probe ( 2 ).