Piezoelectric Vortex Sensor Wide Dynamic Range
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Vortex shedding flowmeters face limitations in detecting weak vortex pressure fields in slow flowing fluids, resulting in a limited turndown ratio of about 10:1, which is insufficient for many applications.
Innovation Solution
A high compliance vortex sensor unit with a piezoelectric vane, comprising a piezoelectric polymer film laminated with a compliant substrate and encapsulated in a silicone rubber integument, is designed to detect vortex pressure fields over a wide range of intensities and frequencies, achieving a turndown ratio of 40:1 to 50:1 by enhancing sensitivity to weak fields while withstanding stronger ones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a typical piezoelectric vortex detecting transducer is used, then accurate flow rate measurements can be obtained, but the measurement range is limited to a turndown ratio of about 10:1
Solution Approach 1:
The patent changes the physical parameters of the vortex sensor by using a compliant substrate that allows the piezoelectric vane to flex and adapt to varying vortex pressure field intensities. This enables the sensor to maintain measurement accuracy across a wide turndown ratio of 40:1 to 50:1, overcoming the limited adaptability of conventional rigid piezoelectric transducers.
Solution Approach 2:
The patent employs a composite structure consisting of a piezoelectric polymer film laminated with a compliant substrate and encapsulated in silicone rubber. This composite material approach allows the sensor to simultaneously achieve sensitivity to weak vortex fields and robustness against strong vortex fields, expanding the measurement range while maintaining precision.
2Measurement precision
If the vortex sensor is made more sensitive to detect weak vortex pressure fields in slow flowing fluids, then the minimum detectable flow rate decreases, but the sensor becomes unable to withstand strong vortex pressure fields at high flow rates
Solution Approach 1:
The patent applies beforehand cushioning by encapsulating the piezoelectric vane in a silicone rubber integument. This protective layer cushions the sensitive piezoelectric element against strong vortex pressure fields at high flow rates, preventing damage while allowing the sensor to maintain high sensitivity for detecting weak vortex fields at low flow rates.
Solution Approach 2:
The patent uses flexible shells and thin films by employing a compliant substrate and silicone rubber encapsulation. These flexible structures allow the piezoelectric vane to adapt to varying pressure field intensities, enabling the sensor to detect very weak vortex fields while withstanding strong vortex fields without structural failure.
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 solution enables highly accurate and repeatable flow rate measurements from 0.5 gpm to 20 gpm with 99-100% accuracy, effectively expanding the measurement range and maintaining sensitivity and robustness across varying flow rates.
Implementation Method 1
a piezoelectric vane, comprising a piezoelectric polymer film laminated with a compliant substrate and encapsulated in a silicone rubber integument, is designed to detect vortex pressure fields
Implementation Method 2
Vortex shedding flowmeters operate by creating a series of vortices, commonly called a Karmen vortex street, in a flowing fluid
Data Source
AI summary
A vortex shedding flowmeter has a vortex sensor with a cantilever mounted transducer vane comprising a piezoelectric polymer film laminated together with an elastic substrate and that is encapsulated in an elastomeric integument to enable the transducer vane to withstand vortex pressure fields that span more than three orders of magnitude with sensitivities that provide high turn down ratios.