Magnetic-Inductive Flow Sensor Frequency Tuning

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Solution Overview

Problem

Existing filling devices using magnetic-inductive flow sensors face challenges in maintaining accurate and repeatable flow measurements under varying operating conditions, particularly outside the specified temperature range, leading to potential overfilling and increased material costs due to safety margins.

Innovation Solution

The method involves operating the magnetic-inductive flow sensor with a test magnetic field frequency higher than the standard frequency to determine if a stable magnetic field can be generated, adjusting the working magnetic field frequency accordingly, and recalibrating the sensor to improve measurement accuracy and repeatability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the magnetic field frequency is increased beyond the standard frequency to improve measurement resolution, then the measurement accuracy and repeatability improve, but the stability of the magnetic field decreases

Engineering Contradiction:
Improveflow measurement accuracyVSAvoidmagnetic field stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent applies dynamics by making the magnetic field frequency adjustable rather than fixed. The control unit dynamically selects between a first magnetic field frequency (lower, more stable) and a second magnetic field frequency (higher, better measurement resolution) based on operational requirements. This dynamic adjustment allows the system to optimize between stability and measurement precision depending on the filling phase and conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the magnetic field frequency parameter to resolve the contradiction. By operating at different frequency values (first frequency for stability, second frequency for measurement resolution), the system can adapt to different operational demands. The control unit monitors conditions and switches between frequency parameters to maintain both stability when needed and measurement accuracy when needed.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If a higher magnetic field frequency is used to improve measurement resolution, then the filling process precision improves, but the risk of electrochemical processes at electrodes increases

Engineering Contradiction:
Improvefilling process precisionVSAvoidelectrochemical processes at electrodes
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent uses periodic action by alternating between different magnetic field frequencies during the filling process. The control unit switches between the first (lower) and second (higher) frequencies at different phases of the filling operation. This periodic switching allows the system to benefit from high-frequency measurement resolution during critical phases while using lower frequencies during other phases to minimize electrochemical effects at the electrodes.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts the magnetic field frequency based on the filling phase and detected conditions. During phases where high measurement resolution is critical, the system uses the second frequency; during other phases, it switches to the first frequency to reduce electrochemical processes. This dynamic adaptation allows optimization of both precision and electrode protection throughout the filling cycle.

Inventive Principle:
Principle #15Dynamics

3Productivity

If the magnetic field frequency is increased to reduce the number of measured values needed, then the measurement speed improves, but the measurement accuracy decreases

Engineering Contradiction:
Improvemeasurement speedVSAvoidflow measurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by making the magnetic field frequency adjustable based on operational requirements. The control unit can select between a first frequency (slower but more accurate) and a second frequency (faster but less accurate) depending on the filling phase and conditions. This dynamic selection allows the system to optimize measurement speed when time is critical while maintaining accuracy when precision is paramount.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the magnetic field frequency parameter to balance speed and accuracy. By operating at different frequency values, the system can achieve faster measurements when needed while maintaining higher accuracy during critical measurement phases. The control unit monitors conditions and adjusts the frequency parameter accordingly to optimize the trade-off between productivity and measurement precision.

Inventive Principle:
Principle #35Parameter changes

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

This approach enhances the absolute measurement accuracy and repeatability of filling processes, allowing for precise filling without overfilling and reducing material waste by minimizing safety margins.

Implementation Method 1

a magnetic field generating device (7) for generating a magnetic field (B) passing through the measuring tube (6) perpendicular to the flow direction of the medium flow

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

The measuring principle of magnetic-inductive flow measurement is based on the force acting on moving charge carriers in a magnetic field (Lorentz force) and the resulting charge separation in the medium flow in the area of ​​the magnetic field

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Implementation Method 3

The separated charge carriers generate an electric field in the medium, the strength of which is proportional to the medium's velocity. Using two measuring electrodes on the circumference of the measuring tube, a measuring voltage proportional to the medium's flow can be tapped

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4624873A1Method for operating a filling device having a filling valve
Publication Date: 2025.10.01 KROHNE MESSTECHNICK GMBH & CO KG
  • EP4624873A1 patent drawingFigure 1
  • EP4624873A1 patent drawingFigure 2
  • EP4624873A1 patent drawingFigure 3

AI summary

Described and illustrated is a method (1) for operating a filling device (2) and a corresponding filling device (2) with a filling valve (3) for controlling a medium flow, with a magnetic-inductive flow sensor (4) for measuring the medium flow released by the filling valve (3), and with a control and evaluation unit (5) for controlling the filling valve (3), wherein the magnetic-inductive flow sensor (4) has a measuring tube (6) for guiding the medium flow, a magnetic field generating device (7) for generating a magnetic field (B) passing through the measuring tube (6) perpendicular to the flow direction of the medium flow, wherein the control and evaluation unit (5) controls the magnetic field generating device (7) such that in a standard operation (9), the magnetic field (B) changes its polarity with a standard magnetic field frequency (f_stand) as the work magnetic field frequency (f_work),wherein the control and evaluation unit (5) determines at least one flow measurement value (flow) in the interval (10) of a constant magnetic field polarity and a stable magnetic field (8) on the basis of a standard calibration (kal_stand) as a work calibration (kal_work), and wherein the control and evaluation unit (5) controls the filling valve (3) to carry out a filling process (11) with at least one plateau phase (12) of the flow and an associated plateau flow measurement value (flow_plat) with a defined target filling quantity according to a filling curve (13), wherein the filling curve (13) indicates the degree of opening (O) of the filling valve (3). Increased accuracy of the measurement is achieved in that, in a test phase (14), the control and evaluation unit (5) operates the magnetic field generating device (7) with a test magnetic field frequency (f_test) which is greater than the set work magnetic field frequency (f_work), whereby it is checked (15),whether a stable magnetic field (B) is also generated at the test magnetic field frequency (f_test) in an interval (10) of a constant magnetic field polarity and that when a stable magnetic field (B) is generated, the test magnetic field frequency (f_test) is set and used as the new work magnetic field frequency (f_work).