Magnetic-Inductive Flow Probe With Capacitive Fill-Level Sensing

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Solution Overview

Problem

Existing magnetic-inductive flowmeters lack the capability to determine the fill level of a pipeline, with existing solutions either requiring additional openings that expose electrodes to abrasive and corrosive media or relying on capacitive methods that require galvanic contact with the medium.

Innovation Solution

A magnetic-inductive flow measuring probe with a housing that generates a magnetic field inside a cylindrical housing, using conductive field guidance elements as sensor electrodes to determine fill level capacitance, allowing for capacitive monitoring without direct contact and integrating a coil arrangement for flow velocity measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If level monitoring electrode establishes galvanic contact with the medium, then level monitoring is enabled, but the electrode is exposed to abrasive and corrosive medium

Engineering Contradiction:
Improvelevel monitoring capabilityVSAvoidexposure to abrasive and corrosive medium
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an insulating wall as an intermediary between the level monitoring electrode and the medium. The electrode is arranged in the insulating wall, which acts as a mediator that allows capacitive coupling with the medium for level detection while physically protecting the electrode from direct contact with abrasive and corrosive substances.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces galvanic contact-based level monitoring with capacitive coupling. Instead of requiring direct electrical contact between the electrode and medium, the system uses changes in capacitance caused by the medium's proximity to detect fill level, thereby eliminating the need for mechanical/galvanic contact.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If additional opening is made for level monitoring electrode, then level monitoring is possible, but the electrode remains unprotected and exposed

Engineering Contradiction:
Improvelevel monitoring functionVSAvoidadditional opening in measuring tube
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The insulating wall serves multiple functions: it provides electrical insulation for the measuring tube, protects the level monitoring electrode from the medium, and enables capacitive level sensing. By integrating these functions into a single component, the patent eliminates the need for additional openings while maintaining level monitoring capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If field guidance arrangement serves as sensor electrode, then capacitive fill level determination is enabled without direct contact, but requires integration with coil arrangement

Engineering Contradiction:
Improveprotected capacitive sensingVSAvoidintegration of field guidance and sensing functions
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The field guidance arrangement is designed to perform dual functions: guiding the magnetic field for flow measurement and serving as a capacitive sensor electrode for level monitoring. This multi-functionality reduces the need for separate components while enabling protected capacitive sensing through the insulating wall.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the field guidance arrangement with the capacitive sensing function by arranging the field guidance elements in or on the insulating wall. This combination allows the same structural element to fulfill both magnetic field guidance and level sensing roles, integrating multiple functions into a unified design.

Inventive Principle:
Principle #5Merging (Combining)

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

Enables continuous monitoring of fill level, distinguishing between full and partial filling, and determining flow velocity-dependent quantities by combining capacitive and inductive methods, ensuring the probe is protected from abrasive and corrosive media.

Implementation Method 1

A magnetic-inductive flow meter comprises measuring devices that, based on Faraday's law of electromagnetic induction, detect a flow velocity-dependent quantity of a medium relative to the measuring device

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the field guidance arrangement serves as a sensor electrode for the capacitive determination and/or monitoring of at least one process variable, in particular a fill level of the medium in the pipeline

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP4147012B1Magnetically inductive flow measuring probe and method for determining a fill level
Publication Date: 2025.11.26 ENDRESS HAUSER FLOWTEC AG
  • EP4147012B1 patent drawingFigure 1~2
  • EP4147012B1 patent drawingFigure 3~4

AI summary

The invention relates to a magnetically inductive flow measuring device, in particular a magnetically inductive flow measuring probe, comprising: a housing (2); at least one measuring electrode (3, 4) for forming a galvanic contact with the medium and for tapping an induced voltage in the medium; a device for generating a magnetic field, wherein the device is arranged in the housing (2), wherein the device comprises a field guide assembly (5) and a coil arrangement (6), wherein the field guide assembly (5) functions as a sensor electrode for capacitively determining and/or monitoring at least one process variable, in particular a fill level of the medium in the tube line or the measuring tube. The invention also relates to a method for determining a fill level of a medium in a measuring tube or in a tube line using the magnetically inductive flow measuring device according to the invention.