A capacitive sensor for detection of the level of a medium

Abstract

A capacitive sensor (1) for detecting the level of a medium comprises a control circuit, a supporting structure (2), and a detection structure on the supporting structure (2). The detection structure comprises a plurality of electrodes (E), which each include a connection part (T) and a plurality of detection parts (J), which are connected to the connection part (T) and extend in a direction transverse to a direction of length (X) of the sensor, the detection parts (J) of one electrode (E) being arranged in a substantially interdigitated configuration with respect to the detection parts (J) of another electrode (E). The detection structure includes a plurality of first detection sections (S), which extend in succession in the direction of length (X) and include at least one top section (Si), closest to the proximal end region, and one or more underlying sections (S2, S3, S4), amongst which at least one bottom section (S4), closest to the distal end region, the detection parts (J) of each of the first and second electrodes (E) being at the corresponding first detection section (S). Each first detection section (S) includes a first electrode (E) and one said second electrode (E), the first and second electrodes (E) of each first detection section (S) being set on the supporting structure (2) electrically insulated from one another and with respect to the first and second electrodes (E) of each of the other first detection sections (S). The control circuit is prearranged for selectively applying an electrical potential difference between the first and second electrodes (E) of a corresponding detection section (S), detecting a value of electrical capacitance between them, and determining, on the basis of the aforesaid value of electrical capacitance, the level of the medium, each first detection section (S) being thereby usable for carrying out detections of capacitance in a way independent of the other first detection sections (S).

Description

technical field [0001] The present invention relates to capacitive sensors for detecting the level of common media such as liquids, fluid substances, powdered materials or materials in bulk. The invention has been developed with particular reference to sensors to be installed or integrated in a vehicle tank, such as a fuel tank or a tank of additives necessary for the operation of a motor vehicle engine. Background technique [0002] Level sensors are used in a variety of contexts to detect residual quantities of liquid present in common containers such as tanks. [0003] Some of these sensors are based on the measurement of an electrical quantity such as capacitance or impedance or conductivity / resistivity using at least two electrodes. In some solutions the electrodes are in direct contact with the liquid, while in other solutions the sensor is provided with a housing for isolating the electrodes from the liquid. Sensors in which electrodes are in contact with a liquid a...

AI Technical Summary

Problems solved by technology

However, the operation of these sensors is affected by possible detection errors due to electrical interference or parasitic capacitance

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