Capacitive Level Probe Segmented Electrodes Eliminate Dead Zones

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Solution Overview

Problem

Capacitive filling level measurements face challenges due to variations in the permittivity of filling materials, which require time-consuming calibration processes and result in dead zones and non-linear measurements.

Innovation Solution

A filling level measuring device with a filling level probe having a first and second electrode, integrated with measurement electronics that allow operation in three measurement modes, enabling continuous, permittivity-independent filling level measurement without dead zones.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single measurement electrode is used for capacitive filling level measurement, then the device structure is simple, but dead zones occur and measurement continuity is compromised

Engineering Contradiction:

Improveelectrode structureVSAvoidmeasurement continuity

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The single measurement electrode is divided into two separate measurement electrodes (first measurement electrode and second measurement electrode) arranged one after the other. This segmentation eliminates the dead zone that occurs between electrodes in traditional single-electrode designs, ensuring continuous measurement coverage along the entire measurement section.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If calibration is performed for different filling materials with varying permittivity, then measurement accuracy is improved, but calibration time increases significantly

Engineering Contradiction:

Improvefilling level accuracyVSAvoidcalibration time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The dependency on permittivity values is extracted and eliminated from the measurement process. The evaluation unit determines filling level based on capacitance ratios between measurement electrodes and container wall, rather than requiring absolute capacitance values that depend on material permittivity. This allows universal application across different filling materials without recalibration.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The measurement approach changes from using absolute capacitance values (which vary with permittivity) to using capacitance ratios between different electrode-container configurations. This parameter transformation makes the measurement independent of filling material properties, eliminating the need for material-specific calibration.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If the container cross section or probe diameter varies along the measurement section, then adaptability to different containers is improved, but measurement linearity deteriorates

Engineering Contradiction:

Improvecontainer compatibilityVSAvoidmeasurement linearity

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

Instead of requiring perfect cylindrical geometry for ideal linear measurement, the invention accepts and compensates for geometric variations. By using multiple measurement electrodes and evaluating capacitance ratios, the system achieves accurate linear measurements even when container cross-section or probe diameter varies along the measurement section.

Inventive Principle:

Principle #16Partial or excessive action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution provides a continuous, accurate, and permittivity-independent filling level measurement, reducing calibration time and eliminating dead zones, thus improving the reliability and efficiency of capacitive filling level measurements.

Implementation Method 1

capacitive filling level measurements are known in the prior art and are based on detecting a filling level, i.e. a filling height of liquids and/or bulk materials in a container by using a capacitive sensor to determine changes in capacitance

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

the capacitance value of the capacitor arrangement will increase or decrease. Hence, the capacitance value of the capacitor arrangement is a measure of the filling level or filling height of a filling material in the container

Methodology Applied

Scientific EffectDielectric constant: Dielectric Permittivity

Data Source

PatentUS12326354B2Capacitive filling level probe without dead zone

Publication Date: 2025.06.10 RECHNER IND ELEKTRONIK

AI summary

A filling level measuring device, a method for capacitive filling level measurement of filling material in a container that includes a counter electrode integrated therein using a filling level probe, and a method for calibrating a filling level probe, that includes introducing the filling level probe into the container. The filling level probe has first and second spaced apart electrodes extending successively and substantially parallel to the counter electrode, thereby defining a measurement path. The level probe is operable in a first, second, or third measurement mode, by switching between a measurement potential or a shielding potential that can each be applied to the first and second electrodes, while a counter electrode potential is applied to the counter electrode. For capacitive filling level measurement, relative capacitance changes measured with a calibrated level probe in each measurement mode compared to an empty container, are used.