Resonator Inner Wall Sound Absorption
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Solution Overview
Problem
Existing noise reduction devices, such as Helmholtz resonators, often require additional sound-absorbing layers that are costly and interfere with resonance, and filling these devices with damping materials is complex and expensive, while also causing annoying whistling sounds due to turbulent airflow.
Innovation Solution
An inner wall with predetermined permeability and sound-absorbing properties, such as a perforated plastic film or fleece, is used within the resonator chamber, eliminating the need for additional damping layers and allowing for independent control of resonance frequencies without impairing the Helmholtz effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If additional sound-absorbing layers are placed in front of the inner wall, then sound absorption is improved, but the resonance in the resonator chamber is influenced and the cost increases
Solution Approach 1:
The invention merges the sound-absorbing function with the inner wall itself by making the inner wall air-permeable and sound-absorbing. This eliminates the need for separate additional sound-absorbing layers, thereby reducing device complexity and cost while maintaining effective sound absorption and preserving the resonance characteristics of the resonator chamber.
Solution Approach 2:
The inner wall is designed to serve multiple functions simultaneously: it provides structural containment of the resonator chamber, enables sound absorption through its air-permeable and sound-absorbing properties, and maintains the resonance effect. This multi-functionality eliminates the need for separate dedicated sound-absorbing components.
2Object-affected harmful factors
If the resonator chamber is filled with sound-absorbing damping material, then sound absorption is improved, but the Helmholtz effect is influenced and the manufacturing complexity increases
Solution Approach 1:
The invention merges the sound-absorbing function with the inner wall structure itself, eliminating the need for separate damping materials that would require complex filling processes. The air-permeable and sound-absorbing inner wall provides sound absorption inherently, simplifying manufacturing while preserving the Helmholtz resonance effect.
3Reliability
If wall openings are made in the inner wall for communication with the resonator chamber, then the Helmholtz effect is achieved, but turbulent flow occurs causing whistling sounds
Solution Approach 1:
The invention uses an air-permeable and sound-absorbing inner wall that functions as a porous material. This allows the inner wall to provide sound absorption and enable communication with the resonator chamber without creating the turbulent flow and whistling sounds associated with discrete wall openings, while maintaining the Helmholtz resonance effect.
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 design effectively reduces airborne and structure-borne noise across a wide frequency range without additional sound-absorbing layers, preventing whistling noises and maintaining the Helmholtz effect, thus offering a cost-effective and efficient noise reduction solution.
Implementation Method 1
the inner wall in the area of the at least one resonator chamber additionally is designed to be sound-absorbing due to a predetermined permeability
Implementation Method 2
Devices for reducing airborne and structure-borne noise, so-called Helmholtz resonators, are typically constructed in such a way that communication with a resonance chamber takes place via targeted wall openings
Data Source
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AI summary
The invention relates to a device (1, 1', 1") for reducing airborne and structure-borne sound having at least one resonator chamber (2, 13, 14, 20, 21, 22, 23) arranged between a supply (7, 7") and a discharge (8, 8"), wherein the resonator chamber is delimited transverse to a longitudinal direction (9, 9") outwards by an outer wall (3', 3', 3") and inwards by an inner wall (4, 4', 4"), wherein the resonator chamber (2, 13, 14, 20, 21, 22, 23) is delimited in the longitudinal direction by a first end wall (5, 15) and a second end wall (6, 16, 17) spaced apart therefrom, and wherein the inner wall (4, 4', 4") is designed to be air-permeable with respect to the adjacent resonator chamber (2, 13, 14, 20, 21, 22, 23). The invention is characterized in that the inner wall (4, 4', 4") is designed to be sound-absorbing by a predetermined permeability in the region of the at least one resonator chamber (2, 13, 14, 20, 21, 22, 23).