Fluidic Oscillator With Piezo Control for Independent Pulse Frequency

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Solution Overview

Problem

Traditional oscillators for generating pulsating gas flows are limited in their ability to adjust oscillation frequency independently of gas pressure or flow rate, which is undesirable for various applications.

Innovation Solution

The oscillator incorporates a piezo-electric actuator, specifically a bender actuator, to generate a control signal that can be easily modulated to control the oscillation frequency independently of inlet gas pressure or flow rate, using a bistable fluidic amplifier to amplify this control signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional oscillators are used to generate pulsating gas flows, then the device structure is simple, but the oscillation frequency cannot be adjusted independently of gas pressure or flow rate

Engineering Contradiction:
Improveoscillation frequency adjustmentVSAvoiddevice structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

A piezoelectric actuator is introduced as an intermediary component to generate control signals that independently regulate oscillation frequency. The actuator converts electrical signals to mechanical displacement, controlling the fluidic amplifier's switching between outlets without being influenced by gas pressure or flow rate variations, thus resolving the contradiction between frequency adjustability and device simplicity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The traditional mechanical adjustment method for oscillation frequency is replaced with an electro-mechanical system using a piezoelectric actuator. This substitution allows frequency control through electrical signals rather than mechanical modifications, enabling independent frequency adjustment while maintaining relatively simple device structure

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

Solution Approach 3:

The oscillation frequency is controlled by changing the electrical parameters (voltage frequency) supplied to the piezoelectric actuator rather than changing mechanical or geometric parameters of the oscillator itself. This parameter change approach enables flexible frequency adjustment independent of gas pressure and flow rate conditions

Inventive Principle:
Principle #35Parameter changes

2Speed

If inlet gas pressure is varied to adjust oscillation frequency, then the oscillation frequency can be varied, but the total flow rate of gas through the oscillator is strongly influenced

Engineering Contradiction:
Improveoscillation frequencyVSAvoidgas flow rate
Core Design Contradiction:
SpeedVSQuantity of substance

Solution Approach 1:

The piezoelectric actuator serves as a mediator that decouples the relationship between oscillation frequency and gas flow rate. By introducing this intermediate control component, frequency can be adjusted through electrical signals without directly altering gas pressure, thus maintaining stable gas flow rate while achieving frequency variation

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The direct mechanical control of frequency through pressure variation is replaced with an electro-mechanical control system. The piezoelectric actuator translates electrical frequency control into mechanical switching actions, allowing frequency adjustment without the unwanted side effect of gas flow rate changes

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

3Adaptability or versatility

If a piezo-electric actuator is used to generate control signals, then the oscillation frequency can be controlled independently of gas pressure, but additional components are required

Engineering Contradiction:
Improvefrequency control independenceVSAvoidnumber of components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The piezoelectric actuator performs multiple functions: it generates control signals, modulates gas flow distribution, and enables frequency control. By consolidating these functions into a single component, the increase in device complexity is minimized while achieving frequency control independence from gas pressure

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The piezoelectric actuator acts as a compact intermediary that bridges electrical control and gas flow modulation. This single component replaces what would otherwise require multiple separate control mechanisms, achieving frequency independence while adding minimal complexity to the overall system

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

This solution allows for reliable and independent control of oscillation frequency, enabling efficient modulation of large gas flows with minimal electrical energy consumption, and is suitable for generating small gas bubbles with a narrow size distribution.

Implementation Method 1

the oscillator comprises a piezo-electric actuator for generating said control signal

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The bender actuator actuates by bending in a direction perpendicular to a direction in which the bender actuator extends

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 3

the oscillator comprises a bistable fluidic amplifier for amplifying a control signal

Methodology Applied
Scientific EffectFluidic amplification:

Data Source

PatentEP3895792B1Oscillator for generating two or more pulsating fluid flows from a constant fluid flow and a method of generating fluid bubbles in a liquid
Publication Date: 2025.05.21 ALFA LAVAL ROTTERDAM BV
  • EP3895792B1 patent drawingFigure 1
  • EP3895792B1 patent drawingFigure 2~3
  • EP3895792B1 patent drawingFigure 4~5

AI summary

Oscillator (1b, 1c) for generating two or more pulsating fluid flows from a constant fluid flow, whereby the oscillator (1b, 1c) comprises a first fluid inlet (6) for receiving a fluid flow and a first fluid outlet (2) and a second fluid outlet (2) for each outputting a said pulsating fluid flow, whereby the oscillator (1b, 1c) comprises a bistable fluidic amplifier (6,7,8,9) for amplifying a control signal, whereby the fluidic amplifier (6,7,8,9) is placed between the first fluid inlet (6) and the fluid outlets (2,3), whereby the oscillator (1b, 1c) comprises a piezo-electric actuator (15) for generating said control signal. Also a method of generating fluid bubbles (40) in a liquid, using such an oscillator (1b, 1c) according to any of the previous claims is used, whereby a pulsating fluid flow from the fluid outlets (2,3) is used to generate fluid bubbles (40) in the liquid.