Ultrasonic Flowmeter Transducer Frequency Shift for Broadband Signals

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Solution Overview

Problem

Existing ultrasonic flowmeters produce narrowband measurement signals due to identical vibration behavior of transmitter and receiver transducers, leading to evaluation difficulties and susceptibility to interference from electronic components and temperature dependence.

Innovation Solution

Incorporate mechanical vibration-influencing elements into at least one ultrasonic transducer to shift its natural frequencies relative to another, ensuring a coordinated relationship between the natural frequencies of both transducers to achieve a broadband measurement signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If both ultrasonic transducers are designed with identical vibration behavior and natural frequencies, then the device structure is simple and manufacturing is easier, but the measurement signal becomes narrowband and difficult to evaluate

Engineering Contradiction:
Improvetransducer manufacturing simplicityVSAvoidmeasurement signal bandwidth
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent applies asymmetry by intentionally designing the first and second transducers with different natural frequencies. The first transducer has a first natural frequency while the second transducer has a second natural frequency that is intentionally offset from the first. This asymmetric frequency design creates a broadband measurement signal that combines both frequency components, resolving the contradiction between manufacturing simplicity and measurement signal quality.

Inventive Principle:
Principle #4Asymmetry

2Measurement precision

If electronic components are used to generate additional natural frequencies in ultrasonic transducers, then the measurement signal bandwidth is increased, but the system becomes susceptible to interference and temperature dependence

Engineering Contradiction:
Improvemeasurement signal bandwidthVSAvoidinterference susceptibility
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces electronic frequency generation with a mechanical solution. Instead of using electronic components to generate additional natural frequencies, the invention uses mechanical transducer design with different physical configurations. The first transducer has a first mechanical design producing a first natural frequency, while the second transducer has a different mechanical design producing a second natural frequency. This mechanical substitution eliminates the interference and temperature dependence issues associated with electronic components while achieving the desired broadband measurement signal.

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

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 broadband measurement signal is easier to process and less susceptible to interference, providing improved measurement accuracy and stability.

Implementation Method 1

a first transducer element (8) arranged in the first transducer housing (7) for generating and/or receiving ultrasonic signals

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the first transducer housing (7) and the second transducer housing (9) are designed to be at least partially mechanically oscillatable and to emit or transmit signals

Methodology Applied
Scientific EffectMechanical vibration: Vibration

Implementation Method 3

the mechanical vibration influencing element influences the vibration behavior of the first ultrasonic transducer in such a way that the natural frequencies of the first ultrasonic transducer are frequency-shifted relative to the natural frequencies of the second ultrasonic transducer

Methodology Applied
Scientific EffectNatural frequency shift: Resonance

Implementation Method 4

a measurement signal characterizing the flow, which results from the transmitted ultrasonic signal passing through the first ultrasonic transducer and the second ultrasonic transducer

Methodology Applied
Scientific EffectUltrasonic transmission: Ultrasound

Data Source

PatentEP4293325B1Ultrasonic flow measuring device
Publication Date: 2025.08.20 KROHNE AG
  • EP4293325B1 patent drawingFigure 1~2
  • EP4293325B1 patent drawingFigure 3~4
  • EP4293325B1 patent drawingFigure 5~6

AI summary

An ultrasonic flowmeter (1) for determining the flow rate of a medium is shown and described, comprising at least one pair of ultrasonic transducers (3) comprising a first ultrasonic transducer (4) and a second ultrasonic transducer (5), wherein the first ultrasonic transducer (4) and the second ultrasonic transducer (5) are configured for transmitting and/or receiving ultrasonic signals, wherein the first ultrasonic transducer (4) comprises a first transducer housing (7) and a first transducer element (8) arranged in the first transducer housing (7) for generating and/or receiving ultrasonic signals, wherein the second ultrasonic transducer (5) comprises a second transducer housing (9) and a second transducer element (10) arranged in the second transducer housing (9) for generating and/or receiving ultrasonic signals.wherein the first transducer housing (7) and the second transducer housing (9) are at least partially designed to be mechanically oscillatable and are at least partially excited to mechanical vibrations for signal emission and signal coupling, respectively, and with a control and evaluation unit (11) for controlling the ultrasonic transducers (4, 5) and for evaluating a measurement signal characterizing the flow rate, which is characterized in that at least the first ultrasonic transducer (4) has a first mechanical vibration control element (12) for influencing the vibration behavior of the first ultrasonic transducer (4) and that the mechanical vibration control element (12) influences the vibration behavior of the first ultrasonic transducer (4) in such a way that the natural frequencies of the first ultrasonic transducer (4) are frequency-shifted relative to the natural frequencies of the second ultrasonic transducer (5), such that the measurement signal characterizing the flow rate,the ultrasound signal resulting from the transmission of the ultrasound signal passing through the first ultrasound transducer (4) and the second ultrasound transducer (5) is broadband, in any case more broadband than after passing through only one of the ultrasound transducers (4, 5).