Vibrating Flowmeter Asymmetric Flow Detection

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Solution Overview

Problem

Existing vibrating flowmeters lack the ability to detect obstructions or residue build-up in flow tubes, which affects the accuracy of mass flow measurements.

Innovation Solution

The integration of strain gages with Wheatstone bridge circuits in a flowmeter configuration allows for the detection of asymmetric flow between flow tubes, enabling the identification of obstructions or residue accumulation by measuring strain differences and outputting signals indicative of flow asymmetry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional vibrating flowmeters are used, then mass flow measurement is achieved, but the ability to detect obstructions or residue build-up is lost

Engineering Contradiction:
Improvedetection capabilityVSAvoidobstruction detection information
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The flowmeter is segmented into multiple independent flow tubes, each equipped with its own strain gage measurement system. By monitoring each tube individually and comparing their responses, the system can detect obstructions or residue build-up in specific tubes that would otherwise go undetected in traditional single-tube designs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Strain gages serve as intermediary sensors that directly measure mechanical strain in the flow tubes. These strain measurements provide intermediate data that reveals information about obstructions and residue build-up, which then feeds into the overall flow measurement system to improve reliability and detection capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If strain gages are integrated into the flowmeter, then flow asymmetry detection is enabled, but device complexity increases

Engineering Contradiction:
Improveflow measurement accuracyVSAvoidsensor integration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The strain gage integration system is designed to perform multiple functions: it detects flow asymmetry between tubes, identifies obstructions or residue build-up, and provides data for accurate flow measurement. This multi-functionality justifies the added complexity by delivering comprehensive monitoring capabilities from a single integrated system.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The strain gage measurement system is merged with the existing vibrating flowmeter structure, combining obstruction detection and flow measurement functions into a single integrated device. This merging reduces overall system complexity compared to having separate detection and measurement systems.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If multiple strain gages are used to detect asymmetric flow, then obstruction detection precision is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveflow asymmetry detection precisionVSAvoidassembly complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

Strain gages are strategically positioned at specific locations on the flow tubes where strain measurements provide maximum information about flow asymmetry and obstructions. This localized placement optimizes measurement precision while minimizing the number of sensors required, thereby reducing manufacturing complexity compared to uniform distribution of sensors.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The strain gages are pre-positioned and pre-wired during manufacturing in predetermined locations on the flow tubes. This preliminary arrangement of sensors and their connections simplifies the assembly process and reduces manufacturing complexity, as the precise positioning required for optimal measurement precision is already established during production.

Inventive Principle:
Principle #10Preliminary action

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 solution enables the detection and reporting of flow asymmetry, ensuring accurate mass flow measurements and preventing errors caused by obstructions or residue build-up, thereby improving the reliability of the flowmeter.

Implementation Method 1

two or more strain gages coupled to the two flow tubes and configured to detect a phase of the drive mode vibration

Methodology Applied
Scientific EffectStrain gage measurement: Piezoresistive Effect

Implementation Method 2

one or more bridge circuits in electrical communication with the two or more strain gages, configured to output a signal indicating an asymmetric flow between the two or more flow tubes

Methodology Applied
Scientific EffectWheatstone bridge: Wheatstone Bridge

Implementation Method 3

a driver coupled to the two flow tubes and configured to induce a drive mode vibration in the two flow tubes

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP3129754B1Apparatus and method for detecting asymmetric flow in vibrating flowmeters
Publication Date: 2020.11.11 MICRO MOTION INC
  • EP3129754B1 patent drawingFigure 1
  • EP3129754B1 patent drawingFigure 2
  • EP3129754B1 patent drawingFigure 3

AI summary

A flowmeter is provided that includes a sensor assembly and meter electronics. The flowmeter comprises two or more flow tubes, a driver coupled to the flow tubes that is oriented to induce a drive mode vibration in the flow tubes. Two or more strain gages are coupled to the two flow tubes and oriented to detect the phase of the drive mode vibration. One or more bridge circuits is in electrical communication with the two or more strain gages, wherein the bridge circuits are configured to output a signal indicating an asymmetric flow between the two flow tubes.