Multichannel Flow Tube Vibratory Meter Design

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Solution Overview

Problem

Vibratory meters face challenges in accurately measuring flow rates of multiphase fluids due to decoupling errors, velocity of sound effects, and flow profile issues, which existing solutions only partially address and often increase the complexity or size of the meter.

Innovation Solution

The implementation of a multichannel flow tube with a specific effective diameter and drive frequency calculation, based on the inverse Stokes number and kinematic viscosity, to minimize decoupling and velocity of sound errors, and improve flow profile accuracy without increasing meter size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single large flow tube is used, then the meter can handle higher flow rates, but decoupling errors increase due to larger diameter allowing gas bubbles and particles to separate from bulk fluid

Engineering Contradiction:
Improveflow rate capacityVSAvoidmeasurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The flow tube is divided into multiple parallel channels with smaller effective diameters. This segmentation allows the meter to handle higher total flow rates through multiple channels while each individual channel maintains sufficiently small diameter to prevent decoupling of gas bubbles and particles from the bulk fluid, thereby resolving the contradiction between flow rate capacity and measurement accuracy.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If the flow tube diameter is reduced to minimize decoupling errors, then measurement accuracy improves, but the meter size and dimensions increase adversely

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidmeter dimensions
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

Instead of reducing the diameter of a single flow tube, the invention transitions to multiple parallel channels arranged in a compact configuration. This dimensional reorganization allows the system to achieve the effective small diameter needed for accurate measurement while maintaining a compact overall meter footprint by distributing the flow capacity across multiple smaller channels rather than requiring a single large tube.

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

3Measurement precision

If additional sensors and detectors are added to measure fluid properties, then measurement accuracy improves, but device complexity increases

Engineering Contradiction:
Improvefluid property measurement accuracyVSAvoidmeter complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The multichannel flow tube structure itself provides the measurement capability by creating flow conditions that minimize decoupling errors and improve measurement accuracy inherently. The geometry and configuration of the multichannel tube serve as the primary measurement mechanism, eliminating the need for additional complex sensors and detectors to compensate for measurement errors, thereby resolving the contradiction between measurement precision and device complexity.

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 enhances the accuracy of flow rate measurements by reducing decoupling, velocity of sound, and flow profile errors directly, improving the performance of vibratory meters across various fluid conditions without adding complexity or size to the meter.

Implementation Method 1

As material begins to flow through the flow tube(s), Coriolis forces cause each point along the flow tube(s) to have a different phase.

Methodology Applied
Scientific EffectCoriolis force: Coriolis Force

Implementation Method 2

The time delay between the two or more pickoffs is proportional to the mass flow rate of material flowing through the flow tube(s).

Methodology Applied
Scientific EffectPhase difference detection:

Data Source

PatentEP3779375B1Vibratory flow meter with multichannel flow tube
Publication Date: 2023.06.28 MICRO MOTION INC
  • EP3779375B1 patent drawingFigure 1
  • EP3779375B1 patent drawingFigure 2~5
  • EP3779375B1 patent drawingFigure 6

AI summary

Vibratory meters (5), and methods for their use measuring a fluid are provided. Each vibratory meter includes a multichannel flow tube (300) comprising two or more fluid channels (302), a pickoff (170), a driver (180), and meter electronics (20) configured to apply a drive signal to the driver at a drive frequency ω, and measure a deflection of the multichannel flow tube with the pickoff. In examples, at least one fluid channel has an effective diameter that is related to kinematic viscosity, inverse Stokes number, and drive frequency; velocity of sound and drive velocity; or the length of the flow tube. In further examples, the driver may apply a drive signal to the driver having a drive frequency proportional to the kinematic viscosity, inverse Stokes number, and effective diameter; or velocity of sound and effective diameter.