Pipe-Wall Damping Structure for Clamp-On Ultrasonic Flow Sensing
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Solution Overview
Problem
Clamp-on ultrasonic flow meters face interference from structural borne ultrasonic signals, which mask the desired fluid borne signals due to the pipe's effectiveness as a waveguide for structural acoustics, leading to inaccurate fluid flow measurements.
Innovation Solution
The use of a structurally significant housing and piezoelectric films applied to the pipe's outer surface to dampen structural borne ultrasonic vibrations, modifying the pipe's vibrational characteristics and providing alternate energy dissipation paths to attenuate the structural wave component, while enhancing the transmission of fluid borne ultrasonic waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the pipe wall is used as a waveguide for ultrasonic signals, then the structural borne signal can be transmitted with low loss, but the structural borne signal masks the fluid borne signal causing measurement interference
Solution Approach 1:
A damping structure is introduced as an intermediary element between the pipe wall and the ultrasonic signal path. This damping structure selectively absorbs and dissipates the structural borne ultrasonic energy while allowing the fluid borne signal to pass through, thereby mediating the conflict between signal transmission efficiency and interference reduction
Solution Approach 2:
The damping structure converts the harmful structural borne vibrations into beneficial thermal energy through internal friction and material damping. By transforming the masking signal into heat, the harmful structural vibrations are eliminated while the fluid borne measurement signal remains intact
2Object-affected harmful factors
If damping structures are added to the pipe wall, then the structural borne signal is attenuated, but the device complexity increases
Solution Approach 1:
The damping structure employs thin flexible damping layers or films applied to the pipe wall surface. These thin films provide effective structural vibration damping without adding significant structural complexity, maintaining the simplicity of the overall device while achieving the desired noise reduction
Solution Approach 2:
The damping characteristics of the structure are modified by changing material parameters such as damping coefficient, thickness, and material composition. By adjusting these parameters, optimal attenuation of structural borne signals is achieved without requiring complex multi-component damping systems
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 approach effectively reduces the impact of structural noise, improving the signal-to-noise ratio and enabling more accurate fluid flow velocity measurements by preferentially damping structural vibrations and enhancing the transmission of fluid borne signals.
Implementation Method 1
at least one damping structure for securing at least one sensor to the wall of the pipe, wherein the at least one damping structure is associated with the outer wall of the pipe for damping the ultrasonic signal propagating within the wall of the pipe
Implementation Method 2
modifying the damping characteristics of the pipe wall by providing multiple impedance changes in the pipe wall and by providing alternate energy dissipation paths for the ultrasonic signals
Implementation Method 3
The use of a structurally significant housing and piezoelectric films applied to the pipe's outer surface to dampen structural borne ultrasonic vibrations
Data Source
AI summary
A method and apparatus for damping an ultrasonic signal propagating in the wall of a pipe, the apparatus including at least one damping structure for securing at least one sensor to the wall of the pipe, wherein the at least one sensor includes a transmitter component and a receiver component for transmitting and receiving an ultrasonic signal, wherein the at least one damping structure is associated with the outer wall of the pipe for damping the ultrasonic signal propagating within the wall of the pipe and a processor that defines a convective ridge in the k-ω plane in response to the ultrasonic signals, and determines the slope of at least a portion of the convective ridge to determine the flow velocity of the fluid.