Coupled Fin Sensor Structure for Stable Vibration Mode Separation
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Solution Overview
Problem
Existing fin sensors face challenges with mode separation due to minimal frequency differences between in-phase and out-of-phase modes, leading to calibration errors and impracticality for industrial applications, exacerbated by imbalances caused by the rotation axis of the fins and net motion towards the sensor assembly.
Innovation Solution
The fin sensor design incorporates a base coupled to two fins with transducers, utilizing fin couplers and a balance rib to restrict motion, enhancing axial stiffness and phase separation, and employing varying base hardness for improved calibration and measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the fin rotation axis is controlled by fin position on the plate and driver location, then the fin can be driven to vibrate, but significant net movement occurs towards the sensor assembly causing calibration errors
Solution Approach 1:
The patent introduces a balance bar extending from the base plate to counterbalance the fin assembly. This counterweight mechanism offsets the net movement caused by fin vibration, preventing the sensor assembly from moving towards the conduit centerline and eliminating calibration errors while preserving fin vibration capability
2Adaptability or versatility
If the frequency difference between in-phase and out-of-phase modes is minimal, then the fin can generate mode separation, but calculations of fluid flow characteristics become confounded
Solution Approach 1:
The patent employs asymmetric fin positioning and balance bar configuration to create intentional imbalance in the fin assembly. This asymmetric design generates sufficient frequency separation between in-phase and out-of-phase modes, enabling accurate fluid flow calculations while maintaining mode separation capability
3Adaptability or versatility
If the tube and balance bar are driven to equal in-phase mode shapes, then mode separation can be achieved, but the system becomes difficult or impossible to drive to equal modes
Solution Approach 1:
The patent applies different material properties and structural characteristics to specific regions of the fin assembly. The balance bar and fin portions are designed with differentiated local properties that facilitate independent vibration modes, enabling the system to be driven to equal in-phase modes while maintaining operational ease
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 achieves enhanced mode separation and reduced calibration errors, enabling more accurate fluid flow measurements by stabilizing the motion of the fins and improving the sensor's practicality for industrial use.
Implementation Method 1
at least two transducers (104a and 104b) coupled to the fins (108a and 108b)
Implementation Method 2
the first fin (108a) being coupled to the second fin (108b) by at least one fin coupler (120a and/or 120b)
Implementation Method 3
the balance rib (118) being coupled to one or more of the base (106) and a base coupler (116)
Data Source
AI summary
An embodiment of a fin sensor is disclosed. The embodiment of the fin sensor has a base, the base coupled to a first fin and a second fin, the fin sensor further having at least two transducers coupled to the fins, the first fin being coupled to the second fin by at least one fin coupler.