Ultrasonic Anemometer Transducer Reflection

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Solution Overview

Problem

Pitot tubes used in the aeronautical field are vulnerable to obstructions such as water, ice, or foreign bodies, leading to erroneous measurements of air flow speed, which can be dangerous, especially in bad weather conditions where pilots may not notice the inconsistency.

Innovation Solution

An electronic device with two electroacoustic transducers and a reflecting surface, emitting and receiving chirp-type acoustic signals to determine fluid flow speed by measuring travel times and correcting frequency bands, allowing for reliable and non-intrusive measurement of fluid flow speed without disturbing the flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Pitot tube is used to measure air flow speed, then measurement function is provided, but measurement reliability deteriorates due to obstruction by water, ice, or foreign objects

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidobstruction by water, ice, or foreign objects
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical Pitot tube system with an ultrasonic measurement system. Instead of using physical air inlets that can be blocked, the invention uses ultrasonic transducers to emit and receive acoustic signals through the air stream, measuring flow velocity based on the Doppler effect or travel time differences without any physical obstruction points.

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

Solution Approach 2:

The patent introduces acoustic waves as an intermediary medium to measure flow velocity. Rather than directly measuring pressure differences with physical inlets, the system uses ultrasonic waves that pass through the air stream, allowing indirect measurement of flow velocity while avoiding direct contact with potentially obstructing elements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If Pitot tube measures total and static pressure to determine flow speed, then flow speed measurement is achieved, but device complexity increases due to multiple pressure chambers and differential pressure gauge

Engineering Contradiction:
Improveflow speed measurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the measurement function from the complex multi-chamber Pitot tube structure and implements it using only ultrasonic transducers and signal processing electronics. The physical structure is simplified to essentially one component (the transducer assembly) while maintaining measurement capability through acoustic signal analysis.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical differential pressure measurement system with an acoustic-based measurement system. Instead of using pressure chambers, tubes, and mechanical gauges, the invention uses ultrasonic transducers to emit and receive acoustic signals, with flow velocity determined from signal travel time or frequency shifts, eliminating complex mechanical components.

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

3Reliability

If Pitot tube is fixed on aircraft fuselage to determine relative wind speed, then relative wind measurement is provided, but vulnerability to obstructions increases in adverse weather conditions

Engineering Contradiction:
Improverelative wind measurement reliabilityVSAvoidobstruction by water, ice, or foreign objects
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the exposed mechanical Pitot tube with an ultrasonic measurement system that has no physical air inlets to be blocked. The ultrasonic transducers measure flow velocity through acoustic signals that pass through the air, eliminating the vulnerability to obstructions by water, ice, or foreign objects that plagues traditional Pitot tubes.

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

Solution Approach 2:

The ultrasonic measurement system inherently provides its own protection against obstructions by using acoustic waves that can pass through or around potential blocking elements. The system continues to function even in adverse weather conditions without requiring additional heating, de-icing, or protective mechanisms.

Inventive Principle:
Principle #25Self-service

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 device provides accurate and reliable measurements of fluid flow speed, reducing the risk of erroneous readings due to obstructions and improving safety by eliminating the need for temperature, pressure, or density measurements, thus simplifying the device and enhancing reliability.

Implementation Method 1

a first electroacoustic transducer, adapted to emit and/or receive an acoustic signal along a first central axis

Methodology Applied
Scientific EffectAcoustic signal propagation: Sound

Implementation Method 2

determine, as a function of the distance (h), the angle (θ), the first acoustic signal emitted and the second acoustic signal received, a flow velocity of the fluid

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Implementation Method 3

a surface adapted to reflect an acoustic signal, the surface being arranged at a point of intersection of the first central axis and the second central axis

Methodology Applied
Scientific EffectAcoustic reflection: Reflection

Data Source

PatentEP3781952B1Ultrasonic anemometer
Publication Date: 2024.10.16 ASSOC TRANSFERTS TECH MANS
  • EP3781952B1 patent drawingFigure 1~2
  • EP3781952B1 patent drawingFigure 3~4
  • EP3781952B1 patent drawing

AI summary

The invention relates to an electronic device for measuring the flow speed of a fluid, comprising at least two electro-acoustic transducers suitable for emitting and/or receiving acoustic signals through the flow of the fluid, the electronic device being suitable for determining a measurement of the flow speed of the fluid based on the characteristics of an acoustic signal emitted and those of one or more acoustic signals received, said received acoustic signals corresponding to reflections of the acoustic signal emitted.