Coriolis Flow Meter Magnet Assembly Vibration Resistance

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Solution Overview

Problem

Existing Coriolis mass flow meters face challenges in securely attaching permanent magnets to vibration generators and pickups, leading to potential mechanical damage from vibrations and limited durability, especially under high-temperature conditions.

Innovation Solution

A magnet holder made of non-magnetic stainless steel, coaxially connected to a stainless steel protective housing via welding or soldering, providing a robust and corrosion-resistant assembly that completely surrounds the permanent magnet, ensuring reliable protection and alignment, and using an adhesive for additional security.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a plastic magnet holder is used to protect the permanent magnet, then the magnet is protected from mechanical damage, but the attachment between the magnet holder and protective housing requires comparatively great effort due to permanent vibration load

Engineering Contradiction:
Improveprotection of permanent magnetVSAvoidattachment effort
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The magnet holder material is changed from plastic to non-magnetic stainless steel, fundamentally altering the material parameters to achieve vibration resistance while maintaining ease of assembly through deformation capability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The attachment method is changed from mechanical fastening (screws, clips) to plastic deformation of the magnet holder itself, which permanently deforms the stainless steel to create a secure mechanical lock without requiring separate fastening components

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

2Strength

If a plastic magnet holder is used, then the magnet is protected from mechanical damage, but the service life is limited under high-temperature conditions

Engineering Contradiction:
Improveprotection of permanent magnetVSAvoidservice life
Core Design Contradiction:
StrengthVSDuration of action of stationary object

Solution Approach 1:

The material temperature threshold parameter is increased by selecting non-magnetic stainless steel with a melting point exceeding 1000°C, allowing the magnet holder to withstand high-temperature industrial environments that would degrade plastic materials

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The solution combines non-magnetic stainless steel material properties (high temperature resistance, vibration resistance) with a protective housing structure to create a composite assembly that withstands both mechanical and thermal stresses

Inventive Principle:
Principle #40Composite materials

3Device complexity

If a magnet holder made of magnetic material is used, then the structure is simple, but the magnet holder affects the magnetic field of the permanent magnet

Engineering Contradiction:
ImprovestructureVSAvoidmagnetic field integrity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The magnet holder is specifically designed with non-magnetic material properties in the region surrounding the permanent magnet, creating a localized non-magnetic zone that preserves magnetic field integrity while maintaining structural functionality

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The non-magnetic stainless steel magnet holder acts as an intermediary structure between the permanent magnet and the external environment, providing mechanical support and protection without interfering with the magnetic field, unlike magnetic materials that would distort or absorb the field

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution enhances the service life of the magnet holder by withstanding continuous vibrations and high temperatures without affecting the magnetic field, ensuring the magnet is protected from mechanical damage and maintaining magnetic flux density.

Implementation Method 1

The magnet holder is made of non-magnetic or non-magnetizable stainless steel, so the magnet holder does not affect the magnetic field of the permanent magnet

Methodology Applied
Scientific EffectMagnetic field non-interference: Diamagnetism

Implementation Method 2

the magnet holder being soldered or welded to the protective housing, for example. Suitable welding processes include: resistance welding, especially resistance spot welding, but also other welding processes, e.g. B. laser welding

Methodology Applied
Scientific EffectWelding: Welding

Implementation Method 3

Soft soldering, hard soldering or high-temperature soldering, for example, are suitable as soldering methods

Methodology Applied
Scientific EffectSoldering: Soldering

Implementation Method 4

The material of the protective housing should have a high overall magnetic permeability so that the protective housing can guide the magnetic field lines emanating from the permanent magnet

Methodology Applied
Scientific EffectMagnetic field guidance: Magnetic Field

Implementation Method 5

The magnet holder made of stainless steel is not susceptible to damage from permanent vibrations

Methodology Applied
Scientific EffectVibration resistance: Vibration

Implementation Method 6

using an adhesive for additional security

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2333496B1Coriolis mass flow measuring device and magnet assembly for such a measuring device
Publication Date: 2018.09.19 KROHNE AG
  • EP2333496B1 patent drawingFigure 1~2
  • EP2333496B1 patent drawingFigure 3
  • EP2333496B1 patent drawingFigure 4

AI summary

The flow meter has a measuring tube excited to oscillations, and a magnetic assembly (1) for generating and/or measuring the oscillations. The assembly has a magnetic holder (3) for holding a permanent magnet (2), where the holder is firmly bonded within a protective housing (4) of the assembly, and the holder and the housing are made of nonmagnetic stainless steel. The holder forms a receiving space (5) for the magnet such that the magnet is inserted into the receiving space, where an open end (6) of the holder is plastically deformed for holding the magnet.