Hollow Probe Unit With Detachable Ring Electrodes

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Solution Overview

Problem

Existing capacitive and conductive field devices face challenges with buildup formation, which distorts measurement results, and their construction is often complex and costly, particularly when high frequencies are used to mitigate buildup.

Innovation Solution

A probe unit with a rod-shaped, hollow body made of insulating material, featuring detachable ring-shaped electrodes and integrated fastening units, such as snap elements, allows for easy assembly and ensures electrical isolation without requiring special tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high frequency excitation signal is used to reduce buildup, then measurement accuracy is improved, but device complexity and cost increase

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidelectronics complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the geometric parameters of the electrode structure (introducing a conical outer surface and corresponding conical inner surface) to optimize the electric field distribution. This structural parameter change allows effective measurement at lower frequencies by improving the capacitive coupling, thereby avoiding the need for complex high-frequency electronics while maintaining measurement accuracy.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If complex electrode assembly is used to ensure electrical isolation, then measurement accuracy is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improveelectrical isolation accuracyVSAvoidassembly ease
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent merges the electrical isolation function directly into the structural design of the probe housing. The conical outer surface and conical inner surface are integrated as single-piece components that inherently provide electrical isolation through their geometric configuration and material properties, eliminating the need for separate isolation mechanisms and simplifying assembly.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The electrode assembly is segmented into distinct functional parts: the conical outer surface electrode, the conical inner surface electrode, and the probe housing. Each component is designed as a separate piece that can be manufactured independently and then assembled together, making the manufacturing process simpler while maintaining the electrical isolation required for accurate measurement.

Inventive Principle:
Principle #1Segmentation

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 design simplifies manufacturing and assembly, reduces the risk of buildup, and maintains accurate measurement results by ensuring stable electrical connections and isolation between electrodes.

Implementation Method 1

According to the capacitive measurement principle, the dependence of the response signal on the capacitance of the capacitor formed by the sensor electrode and the wall of the container, or by the capacitor formed by the sensor electrode and a second electrode, is utilized.

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

Depending on the conductivity of the medium, either the medium itself or the insulation of the sensor electrode forms the dielectric of this capacitor.

Methodology Applied
Scientific EffectDielectric: Dielectric

Implementation Method 3

the conductive measuring principle detects whether there is an electrical contact between a probe electrode and the wall of a conductive container or a second electrode via the conductive medium used in the application of the conductive measuring principle.

Methodology Applied
Scientific EffectConduction (electrical): Conduction (electrical)

Data Source

PatentEP3740741B1Probe unit
Publication Date: 2022.06.22 ENDRESS & HAUSER GMBH & CO KG
  • EP3740741B1 patent drawingFigure 1
  • EP3740741B1 patent drawingFigure 2a~2b

AI summary

The invention relates to a probe unit (2) for a capacitive and/or conductive device (1) for determination and/or monitoring of at least one process variable of a medium (4) in a receptacle (3), comprising a rod-shaped probe body (8), which is configured in the form of a hollow body, in particular having a cylindrical wall, and has an internal volume (V), at least one annular electrode (5a, 5b) which can be mounted, in particular releasably, around the wall of the probe body, and at least one fastening unit (9, 10) which is configured to fasten the at least one electrode (5a, 5b), in particular releasably, at a predeterminable position on the probe body (8). The invention further relates to a device (1) for capacitive and/or conductive determination and/or monitoring of at least one process variable of a medium (4) in a receptacle (3) having a probe unit (2) according to the invention.