Vortex Flow Meter Sensor Plate Stiffness and Resonance
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Solution Overview
Problem
Vortex flow meters face challenges in achieving accurate measurements due to the trade-off between measurement accuracy and plate thickness, where thinner plates provide more accurate measurements but are more prone to failure.
Innovation Solution
A vortex flow meter design featuring a diaphragm-supported vortex oscillation sensor plate with thin edges and support struts that increase stiffness and natural resonant frequency, while viscous damping and inertial balancing enhance the system's stability and frequency response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a thin sensor plate is used, then measurement accuracy is improved, but reliability deteriorates due to increased susceptibility to failure
Solution Approach 1:
The sensor plate is divided into multiple segments or elements that can independently respond to vortex-induced vibrations. This segmentation allows each element to be thinner and more responsive (improving measurement accuracy) while the distributed structure reduces the risk of complete failure (improving reliability).
Solution Approach 2:
The sensor plate utilizes composite material construction combining materials with different properties. This allows the plate to achieve the necessary thinness for accurate vortex detection while incorporating materials or structures that enhance durability and resistance to failure.
2Measurement precision
If a thin sensor plate is used, then measurement accuracy is improved, but structural strength deteriorates
Solution Approach 1:
The sensor plate features non-uniform thickness distribution with varying local properties. Critical regions have optimized thickness and material properties to maximize vibration response for accurate measurement, while other regions provide necessary structural support and strength.
Solution Approach 2:
Composite material construction enables the plate to achieve regions of thinness for sensitivity while incorporating reinforcement elements or high-strength materials in specific areas to maintain overall structural integrity.
3Reliability
If support struts are added to increase stiffness, then reliability is improved, but measurement precision may deteriorate due to additional constraints
Solution Approach 1:
The support struts serve as intermediary elements that provide necessary structural support while being designed to minimize their influence on the vortex-induced vibrations. They act as a bridge between the thin sensor plate and the mounting structure, providing stability without significantly constraining the plate's natural oscillation response.
Solution Approach 2:
The support struts are designed with dynamic characteristics that allow them to be flexible at the operating frequency range of vortex oscillations. This enables the struts to provide structural support at static and low-frequency loads while allowing the sensor plate to respond freely to vortex-induced vibrations at higher frequencies.
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
The design improves measurement accuracy and reliability by increasing the natural resonant frequency and signal-to-noise ratio, allowing for a wider frequency range and reduced flapping of the sensor plate edges, thus enhancing the overall performance of the flow meter.
Implementation Method 1
measuring the frequency or period of vortices in a Karman vortex street set up in a moving fluid
Implementation Method 2
Viscous material in contact with the rotatable strut in the isolation chamber, the viscous material damping rotational motion of the rotatable strut
Data Source
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AI summary
A vortex flow meter includes a vortex responsive assembly having a diaphragm. The diaphragm seals a base end of the assembly to form an isolation chamber. The assembly is adapted to seal an opening in a sidewall of a flow passage. Support struts preferably protrude from the assembly into the flow passage. In one configuration, a vortex oscillation sensor plate has a proximate edge supported on the diaphragm and an opposite distal edge that is unsupported. The vortex oscillation sensor plate has upstream and downstream edges preferably supported by the support struts. A pivoting strut extends along a central region of the vortex oscillation sensor plate. The pivoting strut extends through the diaphragm. The pivoting strut transfers vortex oscillations to a sensor. An electronic transmitter circuit receives a sensor output and provides an output related to flow of the fluid.