Acoustic Flow Meter Using Electromagnetic Induction

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Solution Overview

Problem

Conventional non-invasive ultrasonic flow meters face limitations in temperature range, signal degradation due to material stress and coupling medium aging, and require precise clamping and alignment, restricting their application to a narrow temperature range and specific pipe conditions.

Innovation Solution

The design employs a high-frequency induction coil to generate ultrasonic waves without acoustic coupling, allowing for measurements through coatings and at elevated temperatures, with adjustable frequency to compensate for distance tolerances and temperature fluctuations, using a high-frequency induction coil to induce eddy currents and generate ultrasonic waves in a near-surface area of the pipe.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional ultrasonic flow meters use acoustic coupling with the pipe surface, then ultrasonic waves can be generated in the pipe, but the device requires precise clamping and alignment, and is limited to a narrow temperature range

Engineering Contradiction:
Improvesignal qualityVSAvoidinstallation and alignment requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the acoustic coupler component from the system. By using electromagnetic induction to generate ultrasonic waves directly in the pipe wall, the patent removes the need for mechanical acoustic coupling, thereby eliminating the requirements for precise clamping, alignment, and coupling medium maintenance while improving reliability across temperature ranges

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the mechanical acoustic coupling system with an electromagnetic field-based ultrasonic generation system. Instead of using piezoelectric converters that require mechanical contact and acoustic coupling, the patent uses an induction coil to generate eddy currents in the pipe wall, which interact with a magnetic field to produce ultrasonic waves, substituting mechanical coupling with electromagnetic induction

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If acoustic couplers and coupling media are used to generate ultrasonic waves in the pipe, then ultrasonic flow measurement can be performed, but the coupling medium ages and signal quality decreases over time

Engineering Contradiction:
Improveflow measurement capabilityVSAvoidcoupling medium lifespan
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The invention extracts and eliminates the coupling medium from the system. By using electromagnetic induction to generate ultrasonic waves directly in the pipe wall, the patent removes the need for gel-like coupling media that age and deteriorate, thereby eliminating the problem of signal quality degradation over time while maintaining reliable flow measurement capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention enables the pipe wall itself to serve as the medium for ultrasonic wave generation. Through electromagnetic induction, eddy currents are generated directly in the conductive pipe wall, which then generates ultrasonic waves through interaction with a magnetic field, eliminating the need for external coupling media and enabling indefinite operational duration

Inventive Principle:
Principle #25Self-service

3Temperature

If piezoelectric converters are used for high-temperature applications, then flow measurement can be performed at temperatures up to 180°C, but the converters must operate below their Curie temperature and are subject to thermal stress

Engineering Contradiction:
Improveoperating temperature rangeVSAvoidconverter stability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The invention replaces piezoelectric converters with an electromagnetic induction system. By using an induction coil to generate eddy currents in the pipe wall and interacting these with a magnetic field to produce ultrasonic waves, the patent eliminates piezoelectric materials that have Curie temperature limitations, enabling operation at higher temperatures without thermal stress on converters

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the fundamental operating parameters of the ultrasonic generation system from piezoelectric mechanical vibration to electromagnetic induction. This parameter change allows the system to operate at temperatures above 180°C by eliminating the Curie temperature constraint of piezoelectric materials and reducing thermal stress through non-contact electromagnetic coupling

Inventive Principle:
Principle #35Parameter changes

4Reliability

If wedge-shaped acoustic couplers are used to couple ultrasonic waves into the pipe wall, then ultrasonic flow measurement can be performed, but the installation is critical and requires maintaining a defined distance between transmitter and receiver

Engineering Contradiction:
Improveultrasonic wave couplingVSAvoiddistance alignment precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention extracts and eliminates the wedge-shaped acoustic coupler from the system. By using electromagnetic induction to generate ultrasonic waves directly in the pipe wall, the patent removes the need for maintaining defined distances between transmitter and receiver, thereby eliminating critical installation requirements and distance alignment precision constraints

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution enables flow measurement across a wider temperature range, reduces signal degradation, and eliminates the need for coupling media, providing improved measurement accuracy and adaptability by allowing the flow meter to operate without direct contact and through various coatings, while compensating for positioning and temperature-induced signal fluctuations.

Implementation Method 1

the transmitting transducer is designed as a high-frequency induction coil without acoustic coupling of the transmitting transducer to the surface of the object to generate a varying magnetic field in a region of the metallic object near the surface

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

Through the interaction of these eddy currents with a static or quasi-static magnetic field, an ultrasonic wave is generated in the object due to Lorentz forces or magnetostriction

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Implementation Method 3

Through the interaction of these eddy currents with a static or quasi-static magnetic field, an ultrasonic wave is generated in the object due to Lorentz forces or magnetostriction

Methodology Applied
Scientific EffectMagnetostriction: Magnetostriction

Data Source

PatentEP3249367B1Acoustic flow meter
Publication Date: 2020.09.02 ROSEN SWISS AG
  • EP3249367B1 patent drawingFigure 1
  • EP3249367B1 patent drawingFigure 2
  • EP3249367B1 patent drawingFigure 3

AI summary

Acoustic flow meter for the non-invasive determination of the flow or flow rate in electrically conductive objects through which media flow, in particular pipes or pipelines, comprising a transmitting transducer for generating at least one ultrasound wave in the object, which couples into the medium as a longitudinal wave on an inner surface of the object facing the medium, and a receiving transducer for detecting an ultrasound signal in the object, wherein the ultrasound signal is at least partially generated by the longitudinal wave, wherein the transmitting transducer is designed as a high-frequency induction coil without acoustic coupling of the transmitting transducer with the surface of the object for generating a varying magnetic field in a near-surface region of the object, in particular metallic, and the ultrasound wave is generated by the interaction of the varying magnetic field with a static or quasi-static magnetic field in this region.