Sonic Filter Container Wall Acoustic Impedance Matching

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Solution Overview

Problem

The efficiency of sonic filters and separators is reduced due to back reflections at the fluid-container wall interface caused by acoustic impedance mismatch, resulting in less energy being delivered to the fluid, which increases the required acoustic drive power and reduces operating efficiency.

Innovation Solution

Selecting the container wall's material and thickness to ensure a ½ wavelength of a desired frequency exists within the container wall, minimizing back reflections and maximizing energy delivery to the fluid, while also employing an improved excitation method to lower the required acoustic drive power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a transducer is situated outside the container to generate standing waves in the fluid, then the device complexity is reduced and ease of operation is improved, but back reflections occur at the fluid-container wall interface due to acoustic impedance mismatch, resulting in energy loss and reduced operating efficiency

Engineering Contradiction:

Improveease of operationVSAvoidloss of energy

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The container wall is designed as an acoustic intermediary with specific thickness (1/4 wavelength or 1/2 wavelength) and material properties to match acoustic impedance between the transducer and fluid, reducing back reflections and improving energy transfer efficiency

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The container wall thickness is specifically optimized to 1/4 wavelength or 1/2 wavelength of the desired frequency to create constructive interference and minimize acoustic reflections, thereby maximizing energy delivery to the fluid

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If the container wall thickness and material are optimized to minimize back reflections, then energy delivery to the fluid is maximized and operating efficiency is improved, but the device complexity increases due to specific manufacturing requirements

Engineering Contradiction:

Improveloss of energyVSAvoiddevice complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The container wall is constructed from specific materials with controlled acoustic impedance properties to match the fluid and transducer, reducing reflections and improving energy transfer while maintaining structural integrity

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If standard container wall materials and thicknesses are used, then ease of manufacture is improved, but back reflections reduce the maximum energy delivery to the fluid, increasing the required acoustic drive power

Engineering Contradiction:

Improveease of manufactureVSAvoidpower

Core Design Contradiction:

Ease of manufactureVSPower

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The container wall, which normally causes harmful reflections due to acoustic impedance mismatch, is redesigned with specific thickness and material properties to convert it into a beneficial acoustic transformer that enhances energy transfer to the fluid

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 approach significantly enhances the operating efficiency of sonic filters and separators by maximizing energy delivery to the fluid, reducing the necessary acoustic drive power and improving overall performance.

Implementation Method 1

the interface between the fluid and the container wall causes back reflections (toward the transducer) due to the mismatch in acoustic impedance between the container wall and the fluid

Methodology Applied

Scientific EffectAcoustic impedance mismatch: Reflection

Implementation Method 2

a standing wave may be set up in a fluid by acoustically driving the fluid

Methodology Applied

Scientific EffectStanding wave: Resonance

Implementation Method 3

ensure about a 1⁄2 wavelength of a desired frequency exists within the container wall

Methodology Applied

Scientific EffectAcoustic resonance: Resonance

Implementation Method 4

The transducer is configured on the outside of the container wall, and is also configured to provide a standing wave into the fluid

Methodology Applied

Scientific EffectAcoustic radiation: Acoustic Radiation Pressure

Data Source

PatentUS9833763B2Optimizing acoustic efficiency of a sonic filter or separator

Publication Date: 2017.12.05 CIDRA CORP SERVICES INC

AI summary

Apparatus features a container and a transducer. The container is made of a selected material and has a container wall with a selected thickness, and configured to hold a fluid therein. The transducer is configured on the outside of the container wall, and is also configured to provide a standing wave into the fluid. The selected thickness and material of the container wall is chosen to ensure about a ½ wavelength of a desired frequency exists within the container wall, so as to substantially reduce back reflections toward the transducer due to any mismatch in acoustic impedance at the interface between the container wall and the fluid, and so as to substantially maximize the amount of energy delivered to the fluid, thus improving the operating efficiency of the apparatus.