Silencer for an air conditioning and/or ventilation system and method of sound attenuation
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Solution Overview
Problem
Air conditioning and ventilation systems generate noise due to airflow through ducts, which can transmit noise between rooms and increase noise levels in installation rooms.
Innovation Solution
A silencer with two sections: a sound-absorbing jacket adjacent to the noise source and a sound-insulating jacket further away, allowing sound to be directed into the installation room without significantly increasing noise levels, while maintaining airflow and minimizing transmission to other rooms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a silencer with uniform sound insulation is used throughout the air duct, then noise transmission to adjacent rooms is reduced, but noise levels in the installation room increase significantly
Solution Approach 1:
The silencer is divided into two sections with different sound insulation properties: a first section with high sound insulation (first outer shell) to prevent noise transmission to adjacent rooms, and a second section with lower sound insulation (second outer shell) to allow noise to be discharged into the installation room where it does not disturb occupants. This local differentiation of insulation properties resolves the contradiction by directing noise away from sensitive areas while venting it into tolerant areas.
2Object-affected harmful factors
If a long silencer with uniform sound absorption is used, then noise transmission is reduced, but the installation space required increases
Solution Approach 1:
Instead of using a long uniform silencer, the invention employs a compact design with two distinct sections of different lengths and insulation properties. The first section (with high insulation) is shorter, while the second section (with lower insulation) is longer, creating an asymmetric structure that achieves effective noise control in a reduced overall volume compared to traditional uniform designs.
Solution Approach 2:
The silencer is segmented into two functional sections with different acoustic properties. This segmentation allows each section to perform its specific function efficiently - the first section for noise blocking and the second for noise discharge - thereby achieving the required noise reduction performance in a more compact overall structure.
3Object-affected harmful factors
If sound-absorbing material is placed throughout the entire air duct, then noise is reduced, but airflow resistance and pressure loss increase
Solution Approach 1:
Sound-absorbing material is applied locally only in the first section where high noise reduction is critical, rather than throughout the entire duct system. The second section has minimal or no sound-absorbing material, allowing airflow to pass with less resistance. This localized application maintains noise reduction effectiveness while minimizing the negative impact on airflow and pressure loss.
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 silencer effectively reduces noise transmission to adjacent rooms and maintains low noise levels in the installation room, optimizing airflow and reducing pressure loss.
Implementation Method 1
The first sound-absorbing jacket surrounds the central air duct in a first section of the silencer
Implementation Method 2
The first outer shell surrounds the first sound-absorbing jacket. The first outer shell is sound-insulating
Implementation Method 3
The second outer shell has a lower sound insulation than the first outer shell. The second section is downstream of the first section in the flow direction
Data Source
Figure 1~2
Figure 3~6
Figure 7~10
AI summary
A silencer for an air conditioning and/or ventilation system comprises an inlet (63), an outlet (68), a central air duct (620) arranged between them, a first sound-absorbing jacket (66), and a first sound-insulating outer shell (64). The first sound-absorbing jacket (66) surrounds the central air duct (620) in a first section (60) of the silencer (6), and the first outer shell (64) surrounds the first sound-absorbing jacket (66). A second outer shell (65) surrounds the central air duct (620) in a second section (61) of the silencer (6), wherein the second section (61) is downstream of the first section (60) in the direction of flow (S), or the first section (60) is downstream of the second section (61) in the direction of flow (S). The second outer shell (65) has lower sound insulation than the first outer shell (64).The silencer (6) can be designed to be compact and it allows the sound to propagate into an environment where the sound is not disturbing.