Folded Pole Shoe and Field Guide for Magnetic Flowmeter

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Solution Overview

Problem

The connection between the field guide and the magnet system in electromagnetic flow meters is critical and prone to poor contact, leading to increased magnetic resistance and a worse signal-to-noise ratio due to mechanical stress and changes in contact pressure.

Innovation Solution

A magnetic-inductive flow meter design featuring a magnet system with folded pole shoe and field guide plates that form a stable magnetic and mechanical contact, ensuring a good transition of the magnetic field, and a pressing device to maintain constant contact, which includes elements like clipping, potting, gluing, or screwing for secure alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If flat contact surfaces are used to connect field guide and coil systems, then the structure is simple, but magnetic resistance increases significantly due to poor contact

Engineering Contradiction:
Improvestructure simplicityVSAvoidmagnetic resistance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The contact surface is segmented into multiple folded plates instead of a single flat surface. The field guide and pole shoe are divided into multiple folded sections that interlock, creating multiple contact points and pathways for magnetic flux, thereby reducing magnetic resistance while maintaining structural simplicity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The contact interface is transitioned from a two-dimensional flat surface to a three-dimensional folded structure. The folded plates create multiple layers and dimensions of contact, increasing the effective contact area and improving magnetic connection without significantly increasing overall device complexity

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

2Ease of manufacture

If small changes in contact pressure are allowed, then the device is easy to assemble, but magnetic resistance changes strongly affecting signal quality

Engineering Contradiction:
Improveassembly easeVSAvoidsignal-to-noise ratio
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The folded plate structure provides dynamic adaptation to contact pressure variations. The folds can flex and deform to accommodate assembly tolerances and operational stresses, maintaining stable magnetic contact over time while remaining easy to assemble initially

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The folded structure pre-accommodates potential contact pressure variations through its flexible geometry. The folds act as built-in cushions that absorb mechanical stresses and maintain consistent magnetic contact pressure, preventing signal degradation before it occurs

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Stability of the object's composition

If the field guide is rigidly fixed to ensure stable magnetic field, then magnetic field stability improves, but mechanical stress increases between electrodes

Engineering Contradiction:
Improvemagnetic field stabilityVSAvoidmechanical stress
Core Design Contradiction:
Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The folded plates function as flexible magnetic conduits that can bend and deform elastically. This flexibility allows the field guide to accommodate mechanical stresses and electrode movements while maintaining stable magnetic field guidance, preventing stress concentration and damage

Inventive Principle:
Principle #30Flexible shells and thin films

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 design enhances the magnetic field strength and stability, improving the signal-to-noise ratio and reducing mechanical stress, resulting in more accurate flow measurements.

Implementation Method 1

The functional principle is based on the fact that a flow rate-dependent electrical voltage can be induced in electrically conductive media by means of a magnetic field

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a field guide which is set up to guide the magnetic field between a side of the first coil which is remote from the measuring tube and a side of the measuring tube which is remote from the first coil

Methodology Applied
Scientific EffectMagnetic field conduction: Magnetic Field

Data Source

PatentEP3682198B1Magnetic-inductive flowmeter
Publication Date: 2023.08.16 ENDRESS HAUSER FLOWTEC AG
  • EP3682198B1 patent drawingFigure 1
  • EP3682198B1 patent drawingFigure 2
  • EP3682198B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a magnetically inductive flowmeter (1), comprising: a measuring tube (10) with a measuring tube axis; a magnet system (20) with a first coil system (21) comprising a first coil (21.1) and a first coil core (21.1) which is arranged within the first coil, said magnet system being designed to generate a magnetic field which is oriented perpendicularly to the measuring tube axis; at least two measuring electrodes (30) for tapping an electric voltage induced in the medium; and a field guide (40) which is designed to guide the magnetic field between a first coil side facing away from the measuring tube and a measuring tube side facing away from the first coil, said magnet system having a first pole shoe (21.3) which is designed to conduct the magnetic field between the measuring tube and the field guide. The invention is characterized in that the first pole shoe has at least one folded pole shoe sheet, and the field guide has at least one folded field guide sheet, wherein the first pole shoe and the field guide are magnetically and mechanically contacted at least in an inner region of the first coil.