Ultrasonic Flow Meter Guided Wave Transducer Design
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Solution Overview
Problem
Conventional ultrasonic meters are prone to measurement errors due to their inability to accurately account for flow changes between laminar and turbulent flows, as they only measure average flow velocity in a specific area, leading to potential hysteresis issues and increased complexity when trying to correct for these changes.
Innovation Solution
The ultrasonic meter excites guided waves that radiate compression waves over a large excitation width and at an angle, allowing for a more comprehensive sampling of the flow profile, which is then averaged to account for various parts of the flow profile, thereby improving measurement accuracy and reducing sensitivity to flow changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ultrasonic meters measure average flow velocity in a specific area, then the measurement setup remains simple, but measurement accuracy deteriorates due to inability to account for flow changes between laminar and turbulent flows
Solution Approach 1:
The patent divides the flow measurement into multiple discrete ultrasonic beams traveling along different paths through the measuring tube. Each beam measures flow velocity along its specific path, and the control unit combines these individual measurements to calculate the overall flow rate. This segmentation allows accurate sampling of the entire flow profile without requiring a complex single-beam system with multiple correction mechanisms.
Solution Approach 2:
The patent transitions from measuring flow velocity along a single linear path to measuring velocity along multiple paths that collectively sample the entire cross-sectional area of the flow. By distributing ultrasonic beams across different spatial dimensions and angles, the system achieves comprehensive flow profile measurement without concentrating complexity in a single measurement point.
2Measurement precision
If multiple transmitters and receivers are used to reduce measurement errors, then measurement accuracy improves, but device complexity and manufacturing costs increase
Solution Approach 1:
The patent makes each ultrasonic transducer capable of performing multiple functions: transmitting ultrasonic waves, receiving reflected waves, and serving as both a source and detector for different beam paths. This multi-functionality reduces the total number of transducers needed while maintaining accurate multi-path measurement capability, as each transducer contributes to multiple measurement functions simultaneously.
Solution Approach 2:
The patent combines the transmission and reception functions into a unified ultrasonic measurement system where transducers serve dual purposes. By merging the roles of separate transmitters and receivers and allowing each transducer to participate in multiple beam paths, the system achieves comprehensive flow measurement with fewer components than would be required if each function were performed by dedicated separate devices.
3Measurement precision
If pre-conditioning of flow is applied to improve measurement accuracy, then measurement precision improves, but flow resistance increases and setup complexity increases
Solution Approach 1:
The patent replaces mechanical flow conditioning devices (such as flow straighteners, honeycombs, or conditioning sections) with a non-intrusive ultrasonic measurement approach. By using ultrasonic waves to measure flow velocity directly in the existing flow path, the system achieves accurate measurements without introducing mechanical elements that would increase flow resistance or require additional space for flow conditioning.
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 enables more accurate flow measurements by integrating over a larger volume, effectively accounting for the entire flow cross-section, reducing errors and complexity, and maintaining low flow resistance.
Implementation Method 1
These devices use at least one ultrasonic transducer to couple an ultrasonic wave into the fluid flowing through the measuring tube. This wave travels in a straight line or, after several reflections off walls or special reflector elements, is guided to a second ultrasonic transducer.
Implementation Method 2
The flow velocity through the measuring tube can be determined from the transit time of the ultrasonic wave between the transducers, or from the difference in transit time if the transmitter and receiver are reversed.
Implementation Method 3
it is proposed to combine the excitation of guided waves in the measuring tube, which, as will be explained in more detail later, can lead to the radiation of a compression wave into the fluid extending in the direction of propagation of the guided waves
Implementation Method 4
combine the excitation of guided waves in the measuring tube, which, as will be explained in more detail later, can lead to the radiation of a compression wave into the fluid
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
The invention relates to an ultrasonic meter for sensing a flow variable dependent on a flow of a fluid, having a control device (2), a measurement tube (3) which is formed by multiple side walls (7), mutually adjacent side walls being at an angle to each other, and through which the fluid can flow in a longitudinal direction (14) of the measurement tube (3), and a first and a second ultrasonic transducer (5, 6) which are spaced from each other in the longitudinal direction (14) on the measurement tube (3). The first and second ultrasonic transducers (5, 6, 16, 20, 28, 31, 34, 35) each comprise a transducer element (29, 32) or a predefined arrangement of multiple transducer elements (29, 32). The first and/or second ultrasonic transducer (5, 6, 16, 20, 28, 31, 34, 35) can be actuated by the control device (2) to excite an acoustic wave which is guided in a side wall (7) of the measurement tube (3) and can be guided via the fluid to the respectively other ultrasonic transducer (5, 6, 16, 20, 28, 31, 34, 35) and can be sensed there by the control device (2) to determine a signal propagation time. An excitation width (10, 17, 30, 33) of the first and/or second ultrasonic transducer (5, 6, 16, 20, 28, 31, 34) over which the transducer element (29, 32) or the arrangement of transducer elements (29, 32) extends is at least 50% of the width (9) of an inner face (8) of the side wall (7) on which the ultrasonic transducer (5, 6, 16, 20, 28, 31, 34, 35) in question is arranged, and/or a propagation direction (11, 18, 21, 22) of the guided wave which can be excited by the first and/or second ultrasonic transducer (5, 6, 16, 20, 28, 31, 34, 35) is at an angle to the longitudinal direction (14) of the measurement tube (3), and/or the guided wave can be emitted by the first and/or second ultrasonic transducer (5, 6, 16, 20, 28, 31, 34, 35) over a predefined angle range (36).