US 2014/0152326 A1 · Method and System for Fluid Surface Detection

Abstract

The present invention pertains to a method for detecting a fluid surface, comprising the following steps: providing at least one probe having an electric capacitance with respect to its surroundings; moving the probe into or out of a fluid; charging the probe by applying a periodic first electric signal to the probe for activating the probe; applying a periodic third electric signal to one or more electrically conductive regions different from the probe simultaneously with applying the first electric signal to the probe, wherein the third electric signal corresponds to the first electric signal or an amplified/damped first electric signal; at least partially discharging the probe so as to obtain a discharging current; detecting a second electric signal based on the discharging current; analyzing the second electric signal or a signal derived from the second electric signal with respect to the capacitance of the probe; identifying the fluid surface of the fluid based on a change of the capacitance of the probe. It further relates to a corresponding system adapted to perform the method.

Claims15

Dependent claims

A method for detecting a fluid surface (10), comprising the following steps:

providing at least one probe (2) having an electric capacitance (C) with respect to its surroundings;
moving the probe (2) into or out of a fluid (4);
charging the probe (2) by applying a periodic first electric signal (51) to the probe (2) for activating the probe (2);
applying a periodic third electric signal (S3) to one or more electrically conductive regions separate from the probe (2) simultaneously with applying the first electric signal (51) to the probe (2), wherein the third electric signal (S3) is based on the first electric signal (51);
at least partially discharging the probe (2) so as to obtain a discharging current;
detecting a second electric signal (S2) based on the discharging current;
analyzing the second electric signal (S2) or a signal derived from the second electric signal (S2) 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).

6 more elements

An automated system (1) for detecting a fluid surface (10) of fluid (4) contained in a fluid vessel (3), comprising:

at least one probe (2, 2′) having an electric capacitance (C) with respect to its surroundings;
a moving mechanism (9), adapted for moving the probe (2, 2′) relative to fluid (4);
an electric circuitry (18), comprising:
a signal generating circuit (39) connected to the probe (2), configured to generate and apply a first electric signal (S1) to the probe (2) for charging the probe (2) so as to obtain an activated probe (2),
an electric drain (19) for discharging the activated probe (2) to generate a discharging current,
a controllable switch (33′), adapted to alternatively connect the probe (2) to the signal generating circuit (39) or to the drain,
a signal detecting circuit (38) connected to the probe (2), configured to detect a second electric signal (S2) based on the discharging current of the probe (2),
a shield signal circuit (27), adapted to apply a third electric signal (S3) being based on the first electric signal (S1) to one or more electrically conductive regions (2′, 11, 16, 17, 28) separate from the probe (2);
and
a controller (26), set up to control detection of the fluid surface (10).

7 more elements

Dependencies are inferred from the claim text.

Method and System for Fluid Surface Detection

Life of this patent

Method and System for Fluid Surface Detection

Life of this patent

Abstract

Claims15