Recessed Inner Coating for Magnetic-Inductive Flowmeter

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Solution Overview

Problem

Magnetic-inductive flowmeters face issues with the inner coating being damaged or detached by flowing media, especially when measuring fluids with entrained particles, due to susceptibility at transition edges between the coating and the measuring tube surface.

Innovation Solution

The design features a recessed inner coating with a height of 0.1 μm to 1000 μm and a layer thickness of 0.1 μm to 1000 μm, applied only in the recessed area, providing a protected surface and reducing the risk of damage by positioning the coating countersunk relative to the connection cross-section, with electrodes arranged within the recess for perpendicular detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the inner coating is applied to the entire inner surface of the measuring tube, then electrical insulation is improved, but the coating is more susceptible to damage and detachment by the flowing medium

Engineering Contradiction:
Improveelectrical insulationVSAvoidcoating damage and detachment
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The inner coating is applied selectively only in the recessed area where the measuring tube cross-section is larger, rather than covering the entire inner surface. This local application provides sufficient electrical insulation in the critical region while avoiding the transition edges where damage occurs, thus resolving the contradiction between insulation reliability and coating durability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The inner coating is nested within the recessed area of the measuring tube, positioned counter to the flow direction. This nesting arrangement protects the coating from direct contact with the flowing medium while maintaining its electrical insulation function, effectively reducing damage and detachment risks.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Object-affected harmful factors

If the inner coating is applied only partially in the area of the electrodes, then coating damage is reduced, but electrical insulation may be insufficient

Engineering Contradiction:
Improvecoating damageVSAvoidelectrical insulation
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The inner coating is applied specifically in the recessed area where the measuring tube cross-section is larger, providing localized electrical insulation exactly where needed for electrode functionality. This selective application ensures sufficient insulation while minimizing coating exposure to damaging flow conditions.

Inventive Principle:
Principle #3Local quality

3Productivity

If the measuring tube cross-section is constant, then flow profile is maintained, but the inner coating is more exposed to the flowing medium

Engineering Contradiction:
Improveflow measurement accuracyVSAvoidcoating exposure
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The inner coating is nested within the recessed area of the measuring tube, positioned counter to the flow direction. This nesting arrangement protects the coating from direct contact with the flowing medium while maintaining the constant cross-section geometry needed for accurate flow measurement, thus resolving the contradiction between measurement accuracy and coating protection.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 recessed coating configuration significantly reduces the risk of damage and detachment, ensuring reliable electrical insulation and maintaining a constant measuring tube cross-section, thus protecting the inner coating from the flowing medium and preventing flow profile disruptions.

Implementation Method 1

a magnetic field generated by the magnetic device – for example, by coils

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

the charge carriers, ions, or charged particles present in the conductive fluid are deflected by the magnetic field. A voltage is generated at measuring electrodes arranged perpendicular to both the magnetic field and the flow direction due to this charge separation

Methodology Applied
Scientific EffectCharge separation: Hall Effect

Data Source

PatentEP2413107B1Magnetic-inductive flow measuring apparatus
Publication Date: 2020.04.08 KROHNE AG
  • EP2413107B1 patent drawingFigure 1
  • EP2413107B1 patent drawingFigure 2
  • EP2413107B1 patent drawingFigure 3

AI summary

The flowmeter has a measuring tube (1) provided with a rectangular measuring tube cross-section (3) and made of metal. The measuring tube comprises inlet and outlet sections (7, 8) with a connection cross-section. The measuring tube is expanded between the inlet and outlet sections such that a recess of the measuring tube is formed opposite to the connection cross-section. Two electrodes (2) are arranged in the recess such that an internal coating (6) is present in the recess and includes ceramic material selected from titanium oxide or aluminum silicate.