Damping Structure for Clamp-On Ultrasonic Flow Meter
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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 challenges in accurately measuring fluid flow.
Innovation Solution
The use of a damping structure affixed to the pipe, including a housing to modify ultrasonic vibrational characteristics, piezoelectric films, and blocks to attenuate structural vibrations, thereby reducing the impact of structural borne noise and enhancing the transmission of fluid borne signals.
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 attenuation, but the structural component masks the fluid borne component
Solution Approach 1:
The patent divides the pipe wall into different functional zones by applying damping material selectively. The damping material is applied in segments along the pipe circumference, creating zones with different acoustic properties. This segmentation allows the structural signal to be attenuated in specific regions while preserving fluid signal transmission paths, thereby reducing masking effects and improving measurement precision without excessive energy loss.
Solution Approach 2:
The patent applies damping material with specific acoustic attenuation properties to localized regions of the pipe wall where structural signal generation or propagation is problematic. By modifying the local quality of the pipe wall in these specific zones, the structural borne signal is attenuated at its source or along critical propagation paths, while other regions maintain their waveguide properties for fluid signal transmission, thus improving measurement accuracy without overall signal loss.
2Measurement precision
If damping material is applied to the pipe wall, then structural borne signals are attenuated, but the complexity of the device increases
Solution Approach 1:
The patent extracts and isolates the damping function into a separate, removable component that can be applied to the pipe wall independently of the flow metering system. This damping layer or coating can be applied, removed, or adjusted without affecting the core measurement apparatus, thereby improving signal-to-noise ratio while minimizing the increase in overall device complexity. The damping material acts as a standalone element that addresses structural signal attenuation without complicating the main measurement mechanism.
3Measurement precision
If the pipe wall stiffness is increased to reduce structural vibrations, then the propagation of structural borne signals is impeded, but the flexural stiffness modification requires additional structural components
Solution Approach 1:
The patent employs composite material structures that combine materials with different mechanical and acoustic properties. The housing or damping structure uses composite construction where layers or components with varying stiffness and damping characteristics are combined to achieve effective vibration attenuation. This composite approach provides the necessary flexural stiffness modification to impede structural signal propagation while maintaining a relatively simple overall structure, as the composite materials themselves provide both structural support and damping functions.
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 proposed solution effectively dampens structural borne ultrasonic signals, improving the signal-to-noise ratio and enabling more accurate fluid flow measurements by minimizing the interference from ring-around signals, thus enhancing the reliability of ultrasonic flow meter readings.
Implementation Method 1
The substrate is comprised of a piezoelectric film and the tunable circuit is comprised of a RLC circuit
Implementation Method 2
The damping structure dampens the structural component of the ultrasonic signal to impede propagation of the structural component to the receiver
Data Source
AI summary
An apparatus is presented for damping an undesired component of an ultrasonic signal. The apparatus includes a sensor affixed to a pipe. The sensor includes a transmitter and a receiver. The transmitted ultrasonic signal includes a structural component propagating through the pipe and a fluid component propagating through a flow in the pipe. The receiver receives one of the transmitted components. The apparatus includes a damping structure. The damping structure dampens the structural component of the ultrasonic signal to impede propagation of the structural component to the receiver. The damping structure includes one of a housing secured to the pipe to modify ultrasonic vibrational characteristics thereof, a plurality of film assemblies including a tunable circuit to attenuate structural vibration of the pipe, and a plurality of blocks affixed to the pipe to either reflect or propagates through the blocks, the undesired structural component of the ultrasonic signal.