Ultrasonic Flowmeter With Lamb-Wave Reference Path Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ultrasonic flowmeters with transducers on the outside of the measuring tube face challenges in accurately determining the coupling angle and path of ultrasonic signals due to dependencies on measuring tube material, thickness, and medium parameters, leading to systematic errors in flow measurements.
Innovation Solution
Incorporating a third ultrasonic transducer to define a reference path for Lamb waves in the measuring tube wall, allowing for the determination of Lamb wave propagation velocity, which is used to correct the measurement path and transit time, thereby improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If ultrasonic transducers are arranged on the outside of the measuring tube, then the flow measurement can be performed without interrupting the medium flow, but the coupling angle and signal path become uncertain leading to systematic errors
Solution Approach 1:
The patent introduces a reference path through the measuring tube wall as an intermediary element. By measuring the propagation time of ultrasonic signals along this reference path (which travels through the tube wall material), the system can calculate the actual coupling angle and signal path length in the medium, thereby correcting the flow measurement and eliminating systematic errors caused by uncertain coupling conditions
Solution Approach 2:
The system uses the reference path measurement as feedback to continuously determine the actual coupling angle and signal path characteristics. This feedback information is then used to correct the flow velocity calculation, ensuring accurate measurements even when coupling conditions vary due to changes in tube material, thickness, or medium properties
2Adaptability or versatility
If the coupling angle depends on measuring tube parameters and medium parameters, then the system can adapt to different materials and conditions, but the signal path becomes uncertain causing systematic errors
Solution Approach 1:
The reference path acts as an intermediary measurement channel that travels through the tube wall material. By measuring ultrasonic propagation time along this known path, the system can calculate the actual coupling angle and signal path length in the medium, thereby determining the exact signal path even when coupling conditions vary with different tube materials, thicknesses, or medium properties
Solution Approach 2:
The system dynamically determines coupling angle and signal path parameters based on actual measurements from the reference path. Instead of relying on fixed or assumed parameters, the system continuously adapts the measurement parameters (coupling angle, path length) based on the measured propagation time through the tube wall, ensuring accuracy across varying conditions
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 method enhances the accuracy of flow velocity determination by precisely defining the measuring path and transit time within the tube, reducing systematic errors and improving overall measurement precision.
Implementation Method 1
at least a first and a second ultrasonic transducer, wherein the first ultrasonic transducer and the second ultrasonic transducer are each configured as an ultrasonic transmitter and/or an ultrasonic receiver
Implementation Method 2
evaluating the measured signals... determines the velocity of a medium flowing through the measuring tube
Implementation Method 3
the reference path L0 comprises the path of the Lamb wave emitted by at least one ultrasonic transmitter into the measuring tube wall
Data Source
AI summary
An ultrasonic flowmeter includes at least a first, a second, and a third ultrasonic transducer, and a control and evaluation unit for controlling the ultrasonic transducers and for evaluating measured signals. The flowmeter is configured such that, during operation, the first and second ultrasonic transducers are arranged on a measuring tube offset relative to one another such that a measuring path is present therebetween. The measuring path is defined by the course of the ultrasonic measuring signal during operation. The third ultrasonic transducer is arranged on the measuring tube during operation such that an additional reference path is defined, which includes the course of the Lamb wave emitted by at least one ultrasonic transmitter into the measuring tube wall. The control and evaluation unit determines the velocity of a medium flowing through the measuring tube taking into account the propagation velocity of the Lamb wave in the measuring tube wall.