Vibrating Meter Differential Flow Correction

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Solution Overview

Problem

Existing vibrating meter systems, such as Coriolis flow meters, face challenges in maintaining accurate differential flow measurements across multiple sensors due to changes in operating conditions like temperature and pressure, leading to variations in zero offset, which can result in errors, especially when multiple meters are connected in series for applications like fuel consumption and leak detection.

Innovation Solution

A fluid flow system with a pipeline and two vibrating meters, each with a sensor assembly, is configured to determine flow rates and a differential flow rate, with a system controller that compares the differential flow rate to a threshold value or band, correcting flow characteristics if it falls below this threshold by adjusting the flow rates or determining a new differential zero offset to ensure accurate measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If multiple vibrating meters are connected in series to measure differential flow rates for fuel consumption and leak detection applications, then the ability to detect flow differences and leaks is improved, but measurement precision deteriorates due to zero offset variations caused by changes in operating conditions such as temperature and pressure

Engineering Contradiction:
Improvedifferential flow detection capabilityVSAvoidflow measurement accuracy
Core Design Contradiction:
Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The patent dynamically adjusts the zero offset parameter based on operating conditions (temperature, pressure, fluid density) to maintain measurement precision. The system continuously monitors these parameters and modifies the zero offset accordingly, transforming a static calibration parameter into a dynamic one that adapts to changing conditions, thereby resolving the contradiction between maintaining precision and operating across varying conditions

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system implements a feedback mechanism where the measured differential flow rate and operating conditions are continuously monitored, and the zero offset is adjusted based on this feedback. When the system detects deviations caused by changing conditions, it automatically compensates by updating the zero offset, creating a closed-loop control system that maintains measurement accuracy despite environmental variations

Inventive Principle:
Principle #23Feedback

2Ease of operation

If a fixed zero offset is used for calibration to simplify operation, then ease of operation is improved, but reliability deteriorates as the zero offset changes over time due to variations in temperature, pressure, and sensor mounting conditions

Engineering Contradiction:
Improvecalibration simplicityVSAvoidmeasurement consistency over time
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary calibration to establish an initial zero offset, but then implements continuous or periodic automatic recalibration to maintain reliability. This preliminary action is followed by ongoing adjustments that automatically update the zero offset based on current operating conditions, combining the simplicity of initial calibration with the reliability of continuous adaptation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent transitions the zero offset from a static, fixed parameter to a dynamic parameter that can change over time. The system allows the zero offset to be updated automatically based on real-time monitoring of operating conditions, making the calibration adaptable rather than fixed, thereby maintaining reliability without requiring frequent manual intervention

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If manual zero calibration is performed by stopping flow and closing valves to provide a reference at process conditions, then measurement precision is improved at the calibration point, but productivity deteriorates due to the time-consuming nature of the calibration process

Engineering Contradiction:
Improvezero offset accuracyVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system performs self-calibration by automatically determining the zero offset based on operating conditions without requiring manual intervention to stop flow or close valves. The meter uses its own sensors to monitor temperature, pressure, and flow conditions, and automatically adjusts the zero offset accordingly, enabling the calibration process to serve itself without external assistance, thereby eliminating downtime and maintaining productivity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the mechanical calibration process (which requires physically stopping flow and closing valves) with an electronic/software-based solution. The system uses digital signal processing and algorithmic calculations to determine and adjust the zero offset based on sensor data, substituting mechanical operations with electronic computations, thereby maintaining precision while eliminating the need for flow interruption and manual calibration procedures

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

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 improves the accuracy of differential flow measurements by correcting for errors caused by changes in operating conditions and ensures that multiple vibrating meters provide consistent readings, reducing the risk of false readings and improving the reliability of applications like fuel consumption monitoring.

Implementation Method 1

a magnet and an opposing drive coil have received great success in the flow meter industry. An alternating current is passed to the drive coil for vibrating the conduit(s) at a desired flow tube amplitude and frequency

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the pick-off sensors can use the motion provided by the driver to induce a voltage

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

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

Methodology Applied
Scientific EffectCoriolis force: Coriolis Force

Data Source

PatentEP2729771B1Method and apparatus for determining differential flow characteristics of a multiple meter fluid flow system
Publication Date: 2019.01.09 MICRO MOTION INC
  • EP2729771B1 patent drawingFigure 1
  • EP2729771B1 patent drawingFigure 2
  • EP2729771B1 patent drawingFigure 3

AI summary

A fluid flow system (300) is provided. The fluid flow system (300) includes a pipeline (302) with a flowing fluid. The fluid flow system (300) further includes a first vibrating meter (5) including a first sensor assembly (10) located within the pipeline (302) and configured to determine one or more flow characteristics, including a first flow rate. A second vibrating meter (5') including a second sensor assembly (10') located within the pipeline (302) is provided that is in fluid communication with the first sensor assembly (10) and configured to determine one or more flow characteristics, including a second flow rate. The fluid flow system (300) further includes a system controller (310) in electrical communication with the first and second vibrating meters (5, 5'). The system controller (310) is configured to receive the first and second flow rates and determine a differential flow rate based on the first and second flow rates. The system controller (310) is further configured to compare the differential flow rate to a threshold value or band and correct one or more flow characteristics if the differential flow rate is less than a threshold value or band.