Coriolis Flow Meter Gusset Mode Separation

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Solution Overview

Problem

Existing Coriolis flow meters face challenges in minimizing the adverse impact of unwanted lateral mode vibrations, which can interfere with the processing of Coriolis response signals and compromise output accuracy, often requiring excessive parts and being limited in applicability to specific designs.

Innovation Solution

The integration of gussets coupled to the flow tubes at bends, specifically positioned between straight portions, to increase the frequency separation between the drive mode and lateral mode frequencies, thereby reducing interference and improving signal processing accuracy without adding unnecessary components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional Coriolis flow meter design is used, then the structure is simple, but the lateral mode frequency is close to drive mode frequency causing signal interference and reduced measurement precision

Engineering Contradiction:
Improvesignal processing accuracyVSAvoidlateral mode vibration interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by adding gussets specifically at the bend portions of the flow tube. These gussets locally modify the structural properties at critical locations where lateral mode vibrations are most problematic, increasing stiffness and raising lateral mode frequency without requiring global structural changes to the entire flow tube.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes physical parameters of the flow tube structure by adding gussets with specific geometric parameters (thickness, width, positioning). This modifies the stiffness distribution and mass distribution of the flow tube, thereby changing the vibration characteristics and increasing the frequency separation between drive mode and lateral mode.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If existing methods to reduce lateral mode interference are applied, then measurement accuracy improves, but the device complexity increases due to excessive parts

Engineering Contradiction:
Improveoutput accuracyVSAvoidnumber of components
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the function of lateral mode suppression with the existing flow tube structure by integrating gussets directly into the bend portions. This combines the structural support function with the vibration control function, eliminating the need for separate lateral mode stabilizers or additional damping components that would increase device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The gussets are designed to automatically provide lateral mode frequency elevation through their inherent structural stiffness. The flow tube with gussets serves itself by using its own modified structure to suppress lateral vibrations, without requiring external active control systems, sensors, or additional adjustable components.

Inventive Principle:
Principle #25Self-service

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 effectively raises the lateral mode frequency, enhancing the separation between vibration modes and reducing noise interference, thereby improving the accuracy of flow meter readings without the need for additional parts or complex configurations.

Implementation Method 1

the flow tubes may be said to be driven in a vertical plane by the driver. These vertical vibrations are relatively large since they are at the first out of phase bending mode of the flow tubes and they are driven at their resonance frequency.

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

The Coriolis deflections of the vibrating flow tubes with material flow also occur in the same vertical plane as the drive vibrations. The Coriolis deflections occur at the drive frequency but the tube deflections have the shape of a bending mode with a higher frequency.

Methodology Applied
Scientific EffectCoriolis force: Coriolis Force

Data Source

PatentEP2359101B1Coriolis flow meter with improved mode separation
Publication Date: 2021.10.13 MICRO MOTION INC
  • EP2359101B1 patent drawingFigure 1
  • EP2359101B1 patent drawingFigure 2
  • EP2359101B1 patent drawingFigure 3

AI summary

A flow meter (20) including one or more flow tubes (103) and a driver (104A, 104B) adapted to vibrate the one or more flow tubes (103) at a drive frequency is provided. The flow meter (20) comprises a gusset (260). The gusset (260) is coupled to and extends along the flow tube (103) such that a frequency separation between the drive frequency and at least a second vibration frequency is increased.