Silencing system
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Solution Overview
Problem
Existing silencing systems for tubular members, such as ventilation ports and air-conditioning ducts, face challenges in achieving both high ventilation performance and soundproofing due to the limitations of sound-absorbing materials, particularly at low frequencies, and the need for resonance-type silencers that are specific to the tubular member's frequency, which restricts general-purpose properties and effectiveness across multiple frequencies.
Innovation Solution
A silencing system with multiple silencers disposed on tubular members, featuring a cavity portion and an opening portion that communicate, incorporating a conversion mechanism to convert sound energy into thermal energy, with specific dimensions and placement to silence a range of resonant frequencies without relying on resonance, ensuring high soundproofing and ventilation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If sound-absorbing materials such as urethane and polyethylene are used to suppress noise transmission, then soundproof performance is improved, but ventilation performance deteriorates due to the need to increase the volume of sound-absorbing material to achieve effective low-frequency absorption
Solution Approach 1:
The invention divides the soundproofing function into multiple frequency-specific silencers arranged along the tubular member. Each silencer targets a specific resonant frequency range, allowing the system to achieve broad-spectrum soundproofing without requiring a single large-volume sound-absorbing material that would block ventilation.
Solution Approach 2:
The invention changes the approach from using sound-absorbing materials that rely on absorption coefficient to using resonance-type silencers that target specific frequencies. By adjusting the parameters of multiple silencers (length, diameter, spacing), the system achieves effective soundproofing across a wide frequency range while maintaining ventilation performance.
2Object-affected harmful factors
If the volume of sound-absorbing material is increased to improve absorption coefficient for low-frequency sound, then soundproof performance is improved, but the size of the ventilation port or air-conditioning duct must be increased
Solution Approach 1:
Instead of using a single large-volume sound-absorbing material, the invention segments the soundproofing function into multiple compact resonance-type silencers. Each silencer is small in volume but targets a specific frequency, collectively achieving broad-spectrum low-frequency noise control without increasing the overall ventilation port size.
Solution Approach 2:
The resonance-type silencers serve multiple functions: they target specific resonant frequencies of the tubular member while allowing other frequencies to pass through. This multi-functionality enables effective low-frequency noise control without requiring the ventilation port to be oversized.
3Object-affected harmful factors
If a resonance type silencer is used to silence sound having a specific frequency, then soundproof performance at that frequency is improved, but general-purpose properties deteriorate because the silencer is specific to the tubular member's frequency
Solution Approach 1:
The invention makes the silencing system universal by using multiple resonance-type silencers with different frequency targets. While each individual silencer is frequency-specific, the collective system can adapt to various tubular members with different resonant frequencies by selecting and arranging silencers appropriately, thus achieving both specificity and general-purpose properties.
Solution Approach 2:
The invention enables general-purpose properties by allowing parameter changes in the silencer configuration. By adjusting the number, spacing, dimensions, and frequency targets of the silencers, the same basic system design can be adapted to different tubular members and frequency requirements, maintaining versatility while achieving effective soundproofing.
4Object-affected harmful factors
If resonance type silencing mechanism is provided in the ventilation sleeve, then resonant sound is silenced, but the silencer size must be increased to 1/4 of the wavelength at resonant frequency
Solution Approach 1:
The invention segments the long silencer that would be required for low-frequency resonance control into multiple smaller silencers distributed along the tubular member. Each small silencer targets a specific frequency band, collectively achieving the soundproofing effect of a single large silencer while maintaining a compact overall size that does not obstruct ventilation.
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 system effectively silences multiple resonant frequencies while maintaining high ventilation performance and general-purpose properties, reducing the size and complexity of the silencing system, and preventing interactions that lead to new resonance peaks.
Implementation Method 1
incorporating a conversion mechanism to convert sound energy into thermal energy
Data Source
AI summary
An object is to provide a silencing system that can achieve both high ventilation performance and high soundproof performance, can silence a plurality of pieces of resonant sound, and has high general-purpose properties since the silencing system does not need to be designed according to a tubular member. In a silencing system where silencers are disposed on a tubular member, the silencers silence sound having a frequency of first resonance of the tubular member, each silencer includes a cavity portion and an opening portion, the opening portions are connected to a sound field space of the first resonance of the tubular member, a conversion mechanism for converting sound energy into thermal energy is disposed in each cavity portion or at a position where the conversion mechanism covers the opening portion, a ratio S1/Sd of the area S1 to the area Sd satisfies “0<S1/Sd<40%” in a case where the area of the opening portion of the silencer is denoted by S1 and the surface area of an inner wall of the cavity portion is denoted by Sd, and the depth Ld of the cavity portion in the traveling direction of an acoustic wave in the silencer satisfies “0.011×λ<Ld<0.25×λ,” in a case where the wavelength of an acoustic wave at the resonant frequency of the first resonance is denoted by λ.