T-Shaped Magnetic Core for Flowmeter Flux Leakage

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Solution Overview

Problem

Magnetic flowmeters with small diameter process pipes face challenges in fitting coil shields around electrode isolation tunnels and maximizing magnetic flux, often experiencing elevated coil temperatures and flux leakage due to incomplete magnetic return paths.

Innovation Solution

A T-shaped magnetic core extending transversely from the flowtube with lateral arms provides a low reluctance magnetic return path, using high permeability materials to enhance flux efficiency, and a non-metallic winding spool to reduce thermal issues, allowing for easier testing and diagnostics by completing the magnetic circuit before housing assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a traditional coil configuration is used in small diameter flowtubes, then the magnetic flowmeter can be compact, but coil temperatures become elevated and magnetic flux leakage increases

Engineering Contradiction:
Improveflowtube diameterVSAvoidcoil temperature
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

A non-metallic spool acts as an intermediary component between the magnetic core and the coil windings. This spool provides thermal isolation, preventing heat transfer from the coil to the flowtube, thereby reducing coil temperature while maintaining the compact small diameter configuration

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The magnetic core is segmented into a T-shaped configuration with separate arms that extend laterally from the stem. This segmentation creates distinct magnetic pathways and improves flux distribution, reducing flux leakage while maintaining compact dimensions

Inventive Principle:
Principle #1Segmentation

2Volume of moving object

If a traditional coil configuration is used in small diameter flowtubes, then the magnetic flowmeter can be compact, but magnetic flux leakage increases due to incomplete magnetic return paths

Engineering Contradiction:
Improveflowtube diameterVSAvoidmagnetic flux leakage
Core Design Contradiction:
Volume of moving objectVSLoss of energy

Solution Approach 1:

The magnetic core is segmented into a T-shaped configuration with a vertical stem and lateral arms. This segmentation creates complete magnetic return paths through the arms, ensuring efficient flux circulation and reducing leakage while maintaining compact small diameter dimensions

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The magnetic core extends in multiple dimensions with lateral arms projecting perpendicular to the flowtube axis. This three-dimensional configuration creates efficient magnetic return paths that were not possible with traditional planar coil configurations, reducing flux leakage in the compact space

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Loss of energy

If more winding turns are used to increase magnetic flux, then flux generation improves, but coil temperature increases

Engineering Contradiction:
Improvemagnetic flux efficiencyVSAvoidcoil temperature
Core Design Contradiction:
Loss of energyVSTemperature

Solution Approach 1:

The non-metallic spool serves as a thermal intermediary that isolates the coil from the flowtube, allowing increased winding turns to improve magnetic flux efficiency without proportionally increasing coil temperature, as the thermal path to the flowtube is blocked

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the material parameter of the spool from metallic to non-metallic, fundamentally altering the thermal conduction properties. This allows the system to accommodate more winding turns for improved flux generation while the non-conductive material prevents heat accumulation

Inventive Principle:
Principle #35Parameter changes

4Object-affected harmful factors

If coil shields are fitted around electrode isolation tunnels, then electromagnetic shielding improves, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improveelectromagnetic interferenceVSAvoidcoil shield installation
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The T-shaped magnetic core structure merges multiple functions: it provides magnetic flux pathways through its arms, acts as a structural support for the coil windings via the non-metallic spool, and creates thermal isolation. This consolidation reduces the number of separate components needed, simplifying the overall device structure while maintaining electromagnetic shielding effectiveness

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

This configuration reduces coil temperature by 40°C, decreases the number of winding turns by 35-44%, and simplifies testing while maintaining signal strength, improving flux generation efficiency and part count reduction.

Implementation Method 1

provides a low reluctance magnetic return path

Methodology Applied
Scientific EffectMagnetic reluctance: Magnetic Reluctance

Implementation Method 2

using high permeability materials to enhance flux efficiency

Methodology Applied
Scientific EffectMagnetic permeability: Ferromagnetism

Implementation Method 3

Due to Faraday's Law of electromagnetic induction, a voltage or Electromotive Force (EMF) is generated between the pair of electrodes disposed in the process fluid

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3019835B1Improved magnetic core configuration for magnetic flowmeters
Publication Date: 2020.01.08 MICRO MOTION INC
  • EP3019835B1 patent drawingFigure 1
  • EP3019835B1 patent drawingFigure 2
  • EP3019835B1 patent drawingFigure 3

AI summary

A flowtube assembly for a magnetic flowmeter (150) is provided. The flowtube assembly includes a flowtube (156) configured to receive a flow of process fluid therethrough. A magnetic core (152) is mounted relative to the flowtube (156) and includes a stem (157) extending from the flowtube (156) to a pair of arms. Each of the arms (153, 155) extends away from the stem (157). A spool (182) having a plurality of magnetic windings (164) is disposed about the stem (157) and spaces the plurality of windings (164) from the flowtube (156).