Coriolis Flow Meter Balance System for Density-Induced Vibration
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Solution Overview
Problem
Single tube Coriolis flow meters become imbalanced with changing fluid densities, leading to adverse effects on performance and reliability, as the center of mass shifts, causing vibrations that compromise measurement accuracy and meter longevity.
Innovation Solution
A balance system comprising a balance bar and brace bars is coupled to the flow tube, positioning the combined center of mass proximate the axis of rotation, minimizing the moment of inertia and reaction forces, thereby maintaining balance across a wide range of densities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single tube Coriolis flow meter is used to avoid pressure drop and plugging issues, then ease of operation is improved, but the flow meter becomes imbalanced with changing fluid densities causing vibrations that worsen measurement precision and reliability
Solution Approach 1:
A balance system comprising a balance bar and brace bars is coupled to the flow tube. The balance bar is positioned below the axis of rotation and has a center of mass that, when combined with the flow tube's center of mass, positions the overall center of mass proximate the axis of rotation. This counterbalances the flow tube and minimizes vibrations caused by fluid density changes, thereby maintaining measurement precision while using a single tube design.
2Device complexity
If the center of mass of the flow tube is positioned above the axis of rotation, then the flow tube structure is simplified, but vibrations increase compromising reliability
Solution Approach 1:
The balance bar is positioned below the axis of rotation and configured with a center of mass that counterbalances the flow tube. The combined center of mass of the flow tube and balance bar lies proximate the axis of rotation, minimizing vibrations and improving reliability without significantly increasing device complexity.
Solution Approach 2:
The balance system introduces an asymmetric configuration where the balance bar is positioned below the axis of rotation while the flow tube remains above it. This asymmetric arrangement creates the necessary counterbalancing effect to minimize vibrations caused by the flow tube's position above the rotation axis.
3Reliability
If balance weights are attached to offset the driver and pickoffs weight, then some balance is achieved, but vibrations from center of mass positioned above the rotation axis are not addressed
Solution Approach 1:
The balance bar serves as a counterweight positioned below the axis of rotation. Its center of mass is specifically configured to counterbalance not only the driver and pickoffs but also the flow tube itself. The combined center of mass of all components lies proximate the axis of rotation, addressing vibrations from the entire assembly rather than just offsetting component weights.
Solution Approach 2:
The balance system combines the balance bar, brace bars, flow tube, driver, and pickoffs into a unified balanced assembly. The centers of mass of all these components are integrated to lie proximate the axis of rotation, creating a combined balanced system that minimizes overall vibrations rather than treating each component separately.
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 configuration ensures accurate measurements, extends the life of the flow meter by minimizing vibrations and reducing the impact of fluid density changes, resulting in improved performance and reliability.
Implementation Method 1
the balance system (211) is sized and located such that the combined center of mass (C cm ) of the curved flow tube (210) and the balance system (211) lies proximate an axis of rotation
Implementation Method 2
positioning the combined center of mass proximate the axis of rotation, minimizing the moment of inertia and reaction forces
Implementation Method 3
a conduit is excited in one or more vibration modes as a material flows through the conduit, and the motion of the conduit is measured at points spaced along the conduit
Implementation Method 4
Coriolis mass flow meters, typically operate by detecting motion of a vibrating conduit that contains a material
Data Source
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AI summary
A flow meter (200) includes a flow tube (210) and a balance system (211). The balance system (211) is coupled to the flow tube (210). Both the flow tube (210) and the balance system (211) have a center of mass. The balance system (211) is sized and located such that the combined center of mass (Ccm) of the flow tube (210) and the balance system (211) lies proximate an axis of rotation of the flow tube (210).