Acoustic Shutter Ventilation Channels for Low-Frequency Noise

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Solution Overview

Problem

Existing acoustic shutter assemblies fail to effectively reduce low-frequency noise while maintaining ventilation capabilities, especially in areas with heavy traffic.

Innovation Solution

The integration of acoustic reflectors between sound-absorbing material layers in the ventilation duct, which creates multiple ventilation channels that disrupt the linear path of sound waves, combined with perforated plates for sound absorption and stability, and varying thicknesses of sound-absorbing materials for enhanced noise reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a simple labyrinth ventilation duct is used, then ventilation is maintained, but low-frequency noise reduction is insufficient

Engineering Contradiction:

Improvelow-frequency noiseVSAvoidventilation capability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The ventilation duct is segmented into multiple parallel channels by acoustic reflectors, creating a complex multi-path structure that disrupts low-frequency noise propagation while maintaining ventilation flow through the distributed channels

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The acoustic reflectors extend the ventilation path from a simple linear duct into a three-dimensional multi-channel structure with varying directions, forcing sound waves to navigate complex paths while air flows through the distributed channels

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If acoustic reflectors are added to block noise, then soundproofing improves, but device complexity increases

Engineering Contradiction:

Improvenoise entryVSAvoidventilation duct structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The acoustic reflectors serve multiple functions simultaneously: they block noise propagation, define ventilation channel boundaries, and provide structural support for the sound-absorbing material, thereby reducing the need for separate components

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The ventilation duct combines acoustic reflectors (rigid material) with sound-absorbing material (porous material) in a composite structure that achieves both noise blocking and sound absorption functions within a single integrated system

Inventive Principle:

Principle #40Composite materials

3Object-affected harmful factors

If uniform thickness sound-absorbing material is used, then manufacturing is simplified, but low-frequency noise absorption is insufficient

Engineering Contradiction:

Improvelow-frequency noise absorptionVSAvoidsound-absorbing material configuration

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The sound-absorbing material is configured with varying thicknesses at different locations within the ventilation duct, with thicker material positioned where low-frequency noise absorption is most critical, optimizing acoustic performance without uniform complexity

Inventive Principle:

Principle #3Local quality

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

Significantly reduces noise entry without compromising ventilation, with the thickest sound-absorbing material layer outside for additional insulation and V-formed reflectors preventing moisture and dust accumulation.

Implementation Method 1

a first layer of sound absorbing material arranged at the inside of the frame and an outer layer of sound absorbing material arranged at the outside of the frame

Methodology Applied

Scientific EffectSound absorption: Acoustic Absorption

Implementation Method 2

a number of acoustic reflectors in the form of plate material are arranged between the first and second layers of sound absorbing material so that the ventilation duct is separated into a number of respective ventilation channels

Methodology Applied

Scientific EffectAcoustic reflection: Reflection

Data Source

PatentUS11566466B2Acoustic shutter assembly

Publication Date: 2023.01.31 RAMBOLL DENMARK CONTRACTING APS

AI summary

The acoustic shutter assembly (1) includes at least one window pane (2, 3) arranged in a frame (4). At least one ventilation duct (7) is arranged in the frame between an outer ventilation opening (8) and an inner ventilation opening (9), extending between a first layer of sound absorbing material arranged at an inside (5) and a second layer of sound absorbing material arranged at an outside. A number of acoustic reflectors (12) in the form of plate material are arranged between the first and second layers of sound absorbing material so that the ventilation duct is separated into a number of respective ventilation channels (13) formed between the acoustic reflectors. Each ventilation channel changes direction at least once between the outer ventilation opening and the inner ventilation opening, thereby at least substantially blocking any linear path from the outer ventilation opening to the inner ventilation opening.