Ultrasonic Flow Meter Envelope Correction for Time-of-Flight Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ultrasound-based fluid velocity measurement techniques are limited by accuracy and flexibility due to factors such as turbulence and temperature variation, particularly in partially filled pipes.
Innovation Solution
A method involving digital time of flight measurement using ultrasonic transducers and digital signal processing, including envelope detection and cross-correlation techniques to calculate time differences between upstream and downstream signals, correcting for cycle and sample slip errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If analog processing is used for ultrasound measurement, then device complexity is reduced, but measurement precision deteriorates due to limited accuracy and flexibility
Solution Approach 1:
The patent replaces analog signal processing with digital signal processing. The system uses ADC (analog-to-digital converter) to convert ultrasonic signals into digital format, enabling more precise measurement through digital envelope detection and time difference calculation. This substitution of analog processing with digital processing resolves the contradiction by achieving higher measurement precision while maintaining acceptable device complexity through efficient digital algorithms.
2Measurement precision
If digital signal processing with envelope detection is applied, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the signal processing into distinct functional stages: envelope detection, threshold crossing identification, and time difference calculation. By breaking down the complex digital signal processing into manageable segments, the system achieves high measurement precision through each optimized stage while keeping overall device complexity controlled through modular implementation.
Solution Approach 2:
The patent utilizes parameter changes in the digital domain, specifically transforming the ultrasonic signal into its envelope representation and detecting threshold crossings. This parameter transformation enables precise measurement of time differences without requiring complex analog circuitry, thus improving measurement precision while managing device complexity through efficient digital parameter manipulation.
3Measurement precision
If envelope-based time difference calculation is used, then measurement precision is improved for fluid velocity, but processing time increases
Solution Approach 1:
The patent applies preliminary envelope detection to the ultrasonic signal before performing time difference calculation. By pre-processing the signal to extract the envelope and identify threshold crossing points, the system prepares the data in advance, which speeds up the subsequent time difference calculation. This preliminary action reduces overall processing time while maintaining high measurement precision through accurate envelope-based measurements.
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
Improves measurement accuracy and reduces power consumption by stabilizing signal measurements through envelope-based corrections, enhancing the precision of fluid flow calculations.
Implementation Method 1
Ultrasonic transducers may be placed within the pipes. Fluid flow may be measured by multiplying fluid velocity by the interior area of the pipe.
Implementation Method 2
determining a first envelope of the first signal, and determining a first time the first envelope crosses a threshold
Data Source
AI summary
In an embodiment, a system for measuring material flow in a pipe is disclosed. A first transducer is operable to transmit a first signal having a first frequency at a first time and receive a second signal at a second time, and a second transducer spaced apart from the first transducer and is operable to receive the first signal and transmit the second signal having the first frequency. A signal processing circuit communicatively coupled to the first transducer and the second transducer, the signal processing circuit is operable to determine a first envelope of the first signal and a second envelope of the second signal and calculate a flow rate based on the first envelope of the first signal and the second envelope of the second signal.