Clamp-on Ultrasonic Flow Meter Pipe Wall Resonance Correction
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Solution Overview
Problem
Clamp-on ultrasonic flow measuring devices face significant measurement uncertainties due to unknown pipeline parameters, such as varying inner diameters and sound-damping properties, which are not effectively compensated for by existing technologies.
Innovation Solution
A method to ascertain pipe wall resonance frequencies using a field device with ultrasonic transducers, which involves determining transfer functions and received spectra to correct flow rate and velocity measurements, and to identify pipeline parameters like thickness and material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If clamp-on ultrasonic transducers are placed externally on the pipeline, then installation can occur without interruption of flow, but measurement uncertainty increases due to unknown pipeline parameters
Solution Approach 1:
The patent applies preliminary action by measuring pipe wall resonance frequencies and determining pipeline parameters (inner diameter, sound velocity, wall thickness) before performing flow measurements. This preliminary characterization of the pipeline allows the system to compensate for measurement uncertainties, resolving the contradiction between easy installation and measurement accuracy.
2Ease of manufacture
If average inner diameter values are used for the pipeline, then installation is simplified, but measurement accuracy deteriorates due to deviations at the measuring point
Solution Approach 1:
The patent changes the parameter approach by determining the actual inner diameter and sound velocity at the specific measuring point through resonance frequency analysis, rather than using average values. This localized parameter determination eliminates measurement errors caused by pipeline variations while maintaining installation simplicity.
3Device complexity
If pipeline parameters are not compensated for, then the measurement process remains simple, but measurement accuracy deteriorates due to sound-damping properties and internal accretion
Solution Approach 1:
The patent applies self-service by enabling the measurement system to automatically determine pipeline parameters (inner diameter, sound velocity, wall thickness) through resonance frequency analysis and use these parameters to compensate for measurement errors. The system self-calibrates without requiring external intervention, resolving the contradiction between simplicity and accuracy.
4Measurement precision
If pipe wall resonance frequencies are ascertained and used for correction, then flow measurement accuracy improves, but device complexity increases due to additional measurement and evaluation steps
Solution Approach 1:
The patent applies universality by designing the evaluation unit to perform multiple functions: determining pipe wall resonance frequencies, calculating pipeline parameters (inner diameter, sound velocity, wall thickness), and correcting flow measurements using these parameters. This multi-functional approach integrates the additional complexity into a unified system that achieves high measurement accuracy without proportionally increasing device complexity.
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 enhances the accuracy of flow measurements by accounting for pipeline-specific errors, allowing for precise correction of flow rates and velocities, and enables the identification of pipe wall parameters, thereby improving measurement reliability.
Implementation Method 1
a first ultrasonic transducer, which is placed on the pipeline at the measuring point
Implementation Method 2
ascertaining at least one pipe wall resonance frequency fres of a pipeline
Implementation Method 3
They can be operated according to the Doppler principle or according to the travel-time difference principle
Implementation Method 4
They can be operated according to the Doppler principle or according to the travel-time difference principle
Data Source
AI summary
A method for ascertaining at least one pipe wall resonance frequency of a pipeline in the region of a measuring point by means of a field device of process measurements technology having at least a first ultrasonic transducer, which is placed on the pipeline at the measuring point, comprising steps as follows: providing a first transfer function Utransducer(f) at least of the first or a plurality of ultrasonic transducers located in the region of the measuring point; ascertaining a received spectrum Urec(f) from a received signal Urec(t) after transmission of an ultrasonic signal; ascertaining a second transfer function Umeasuring point(f) from the first transfer function Utransducer(f) of the first or the plurality of ultrasonic transducers and from the received spectrum urec(f), wherein the second transfer function Umeasuring point(f) is characteristic for the measuring point; and ascertaining the at least one pipe wall resonance frequency fres, especially a plurality of resonance frequencies, in the region of the measuring point by evaluating the second transfer function Umeasuring point(f) from step III, as well as a clamp-on, ultrasonic, flow measuring device, a method for ascertaining flow, a method for ascertaining a change of the measuring point and an identification device.