Ultrasonic Flowmeter Transducer Caps for Pulse Integrity
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Solution Overview
Problem
Ultrasonic flowmeters face accuracy issues due to the dispersion of ultrasonic pulses as they travel through the fluid, leading to impaired measurement accuracy.
Innovation Solution
The flowmeter design features transducers with vibratory surfaces larger than the duct's cross-sectional diameter, isolated from the fluid by caps, and an optimized duct structure that minimizes signal degradation and ensures directional propagation of ultrasound, reducing scattering and turbulence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If transducers are located at opposite ends of the duct to transmit and receive ultrasonic pulses parallel to the duct, then the flowmeter can measure fluid flow rate, but the ultrasonic pulse spreads and disperses before reaching the second transducer, impairing measurement accuracy
Solution Approach 1:
The patent introduces caps as intermediary elements between the transducers and the fluid. These caps are acoustically coupled to the transducers and have vibratory surfaces that are acoustically coupled to the fluid, serving as a mediator to transmit ultrasonic pulses while preventing direct contact between transducers and fluid. This intermediary structure reduces pulse dispersion and maintains signal integrity.
Solution Approach 2:
The caps act as flexible acoustic coupling elements that can be made of materials with appropriate acoustic impedance. These thin film-like structures allow ultrasonic energy to pass through while isolating the transducers from the fluid, reducing scattering and dispersion of the ultrasonic pulses.
2Reliability
If transducers are isolated from fluid by caps to prevent corrosive effects, then transducer durability is improved, but signal degradation may occur due to the caps
Solution Approach 1:
The patent optimizes the thickness of the caps as a critical parameter to balance protection and signal transmission. By carefully selecting the cap thickness, the system achieves sufficient isolation from corrosive fluid while maintaining adequate acoustic coupling for high-quality signal transmission, minimizing signal degradation.
Solution Approach 2:
The caps are made from materials with specific acoustic properties that combine protective functions with acoustic transmission capabilities. The material selection and composition are designed to provide corrosion resistance while maintaining good acoustic coupling between the transducer and fluid.
3Measurement precision
If the duct diameter is reduced to match the transducer vibratory surface diameter, then ultrasonic pulse dispersion is reduced, but the duct becomes more susceptible to turbulence and scattering
Solution Approach 1:
The patent applies different geometric characteristics to different parts of the duct system. The duct has a larger diameter to reduce turbulence, while the transducer vibratory surfaces have optimized dimensions to control ultrasonic pulse dispersion. This local differentiation of geometric properties allows simultaneous optimization of fluid flow characteristics and ultrasonic signal quality.
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 design enhances the accuracy of fluid flow measurement by maintaining the integrity of ultrasound waves and reducing turbulence, resulting in precise flow rate calculations.
Implementation Method 1
ultrasonic transducers arranged respectively to transmit and receive ultrasonic pulses propagated through such fluid
Implementation Method 2
The transducers are provided with respective vibratory surfaces which transmit and/or receive ultrasound
Implementation Method 3
The thickness of the caps may be such as to optimise coupling between the transducers and such fluid
Implementation Method 4
The caps may be mounted in or on damping mountings to reduce signal degradation owing to ringing of the caps
Implementation Method 5
electronic circuitry connected to the transducers to provide a measure of the time delay between emission of an electronic pulse from one of the transducers and reception of the pulse by the other of the transducers
Data Source
AI summary
An ultrasonic flowmeter comprising an elongate duct through which fluid flows when the flowmeter is in use. Ultrasonic transducers are arranged respectively to transmit and receive ultrasonic pulses propagated through such fluid when the flowmeter is in use. Electronic circuitry is connected to the transducers to provide a measure of the time delay between emission of an electronic pulse from one of the transducers and reception of the pulse by the other of the transducers. The circuitry is constructed to enable an output to be provided which is dependent upon that delay and which is indicative of the rate of flow of fluid through the duct. The transducers are located respectively at opposite ends of the duct and are arranged to transmit and receive ultrasonic pulses propagated through the fluid substantially parallel to the duct from one end thereof to the other. The transducers are provided with respective vibratory surfaces which transmit and/or receive ultrasound, which vibratory surfaces have a diameter which exceeds the cross-sectional diameter of the duct.