Digital Ultrasonic Flow Measurement With Envelope Slip Correction

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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, especially 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, to calculate the time difference between upstream and downstream signals, correcting for cycle and sample slip errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If analog processing is used for ultrasound measurement, then device complexity is reduced, but measurement precision deteriorates due to turbulence and temperature variation

Engineering Contradiction:

Improveprocessing complexityVSAvoidflow measurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces analog signal processing with digital signal processing. Digital processing provides superior noise rejection, enables more sophisticated algorithms for turbulence compensation, and allows for precise measurement even under varying temperature conditions, thereby improving measurement precision while maintaining acceptable device complexity through software-based solutions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs dynamic adjustment of measurement parameters including adaptive thresholding for envelope detection, variable sampling rates, and real-time compensation for temperature and turbulence effects. These parameter changes enable the system to maintain high measurement precision across varying operating conditions while managing device complexity through algorithmic adaptation rather than hardware complexity.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If digital signal processing with envelope detection is applied, then measurement precision improves, but use of energy increases

Engineering Contradiction:

Improvetime difference measurement accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic envelope detection and threshold crossing identification rather than continuous processing. By sampling the ultrasonic signal periodically and only processing it when envelope crossings are detected, the system achieves high measurement precision for time difference while significantly reducing overall power consumption compared to continuous digital processing.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system uses the signal's own envelope characteristics to trigger processing events. The envelope detection and threshold crossing identification allow the system to self-regulate processing based on signal presence, avoiding unnecessary energy consumption during low-signal periods while maintaining precision when needed.

Inventive Principle:

Principle #25Self-service

3Measurement precision

If envelope threshold comparison is used for time difference calculation, then measurement precision improves for cycle slip correction, but device complexity increases

Engineering Contradiction:

Improvecycle and sample slip correction accuracyVSAvoidsignal processing complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces envelope detection as an intermediary step between raw signal acquisition and final time difference measurement. By first extracting the envelope and identifying threshold crossings, the system simplifies the complex task of cycle and sample slip correction into a more manageable process, achieving high precision without excessive device complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 threshold comparisons and delta error correction, enhancing 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.

Methodology Applied

Scientific EffectUltrasonic transmission: Ultrasound

Implementation Method 2

determining a first envelope of the first signal, and determining a first time the first envelope crosses a threshold

Methodology Applied

Scientific EffectEnvelope detection:

Data Source

PatentUS12474190B2Envelope based sample correction for digital flow metrology

Publication Date: 2025.11.18 TEXAS INSTRUMENTS INC

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.