Fresh air system pipeline noise reduction structure

Abstract

The utility model relates to the technical field of building ventilation systems, in particular to a noise reduction structure of a fresh air system pipeline. The utility model provides a fresh air system pipeline noise reduction structure which comprises a pipeline body and a noise reduction assembly, the noise reduction assembly comprises a plurality of noise reduction units arranged at intervals in the axial direction of the pipeline body, and each noise reduction unit is composed of a supporting frame, a porous sound absorption layer, a resonant cavity array and a flow guide cone. The supporting frame is the same as the inner wall of the pipeline body in shape and is fixed to the inner wall of the pipeline body, the porous sound absorption layer is attached to the inner side of the supporting frame, the resonant cavity arrays are located on the two sides of the porous sound absorption layer, and corresponding clamping grooves are formed in the positions, located on the porous sound absorption layer, of the supporting frame. The two ends of the resonant cavity array are fixed to the clamping grooves of the adjacent supporting frames respectively, the flow guide cone is located in the center area of the porous sound absorption layer, and the cone top of the flow guide cone points to the airflow direction.

Description

A noise reduction structure for fresh air system ducts Technical Field

[0001] This utility model relates to the field of building ventilation system technology, specifically to a noise reduction structure for a fresh air system duct. Background Technology

[0002] As the core equipment for air purification and circulation, the high-speed airflow in the duct of the fresh air system can easily cause aerodynamic noise (such as turbulence noise and eddy noise) and mechanical vibration noise, which seriously affects the comfort of the indoor environment.

[0003] Traditional pipe noise reduction structures often use a single porous sound-absorbing material (such as glass wool or polyurethane foam) or a simple resonant cavity design, which has the following shortcomings: First, a single sound-absorbing material is only effective for noise of a single frequency, and its ability to suppress noise of other frequencies is weak; Second, the resonant cavity of a fixed structure is difficult to match the resonance conditions of sound waves of different frequencies, and the noise reduction efficiency fluctuates greatly with frequency; Third, the traditional structure has a strong rigid connection with the pipe wall, and vibration is easily transmitted through rigidity, causing secondary radiated noise. Summary of the Invention

[0004] This utility model provides a silencing structure for a fresh air system duct. Through a composite silencing unit design, it achieves multiple noise reduction goals, including stable airflow guidance, broadband noise absorption, and vibration isolation.

[0005] The technical solution provided by this utility model is a silencing structure for a fresh air system duct, including a duct body and a silencing component. The silencing component includes multiple silencing units spaced apart along the axial direction of the duct body. Each silencing unit is composed of a support frame, a porous sound-absorbing layer, a resonant cavity array, and a flow guide cone. The support frame has the same shape as the inner wall of the duct body and is fixed to the inner wall of the duct body. The porous sound-absorbing layer is attached to the inner side of the support frame. The resonant cavity array is located on both sides of the porous sound-absorbing layer, and the support frame has corresponding slots at the outlet of the porous sound-absorbing layer. The two ends of the resonant cavity array are fixed to the slots of the adjacent support frame. The flow guide cone is located in the central area of ​​the porous sound-absorbing layer, and its cone apex points in the direction of airflow.

[0006] As a preferred embodiment of the present invention, the resonant cavity array is composed of multiple independent cavities arranged in a honeycomb pattern, and the neck opening diameter of each cavity in the resonant cavity array is in the range of 3-8mm.

[0007] As a preferred technical solution of this utility model, the porous sound-absorbing layer has a gradient density structure with multiple sound-absorbing holes. The porosity of the sound-absorbing holes gradually increases and the density gradually decreases along the airflow direction.

[0008] As a preferred technical solution of this utility model, the spacing between adjacent silencing units is 0.8 to 1.2 times the pipe diameter.

[0009] As a preferred embodiment of this utility model, the cone angle of the guide cone decreases by 5-10 degrees along the airflow direction, with the minimum cone angle being 5 degrees.

[0010] As a preferred technical solution of this utility model, the surface of the guide cone is provided with a spiral guide groove with a spiral angle of 15 degrees to 30 degrees.

[0011] As a preferred technical solution of this utility model, an elastic vibration isolation pad is provided between the support frame and the inner wall of the pipe, and the vibration isolation pad is made of EPDM rubber.

[0012] As a preferred embodiment of this invention, a sound-insulating cotton layer is filled between the resonant cavity array and the pipe body.

[0013] As a preferred technical solution of this utility model, the outer wall of the pipe is provided with a sound insulation layer, which has a three-layer structure of first aluminum foil, foamed aluminum and second aluminum foil from the inside to the outside.

[0014] The advantages of this utility model compared with the prior art are as follows:

[0015] 1. Wideband noise reduction: Gradient density porous sound-absorbing layer covers mid-to-high frequency noise absorption, honeycomb resonant cavity array matches low frequency noise resonance conditions, and sound insulation cotton layer supplements low frequency attenuation, achieving noise suppression across the entire frequency band from 200Hz to 5000Hz (noise reduction coefficient ≥0.8).

[0016] 2. Improved airflow stability: The variable cone angle guide cone and the spiral guide groove work together to guide the airflow along a smooth spiral path, reducing turbulence intensity by 40%-60% and reducing secondary eddy noise;

[0017] 3. Reliable vibration isolation: The double protection of the elastic vibration isolation pad and the aluminum foil-foam aluminum composite sound insulation layer on the outer wall of the pipe reduces the vibration transmission rate to below 0.3, avoiding secondary radiation noise caused by rigid vibration;

[0018] 4. Compact and efficient structure: The silencing unit is modularly designed with spacing adapted to mainstream pipe specifications (DN150-DN500), making installation and maintenance convenient. The silencing efficiency per unit length is more than 30% higher than that of traditional structures. Attached Figure Description

[0019] Figure 1 is a structural diagram of a duct silencing structure for a fresh air system according to this utility model.

[0020] Figure 2 is a cross-sectional three-dimensional structural diagram of a duct silencing structure for a fresh air system according to this utility model.

[0021] Figure 3 is an enlarged structural diagram of the sound-absorbing unit at point A of the sound-absorbing structure of the duct of a fresh air system according to this utility model.

[0022] Figure 4 is a structural diagram of the flow guide cone of a fresh air system duct silencing structure according to this utility model.

[0023] As shown in the figure:

[0024] 1. Pipe body; 2. Silencing unit; 3. Support frame; 4. Porous sound-absorbing layer; 5. Resonance cavity array; 6. Flow guide cone; 7. Slot; 8. Sound-absorbing hole; 9. Spiral flow guide groove; 10. Elastic vibration isolation pad layer; 11. Sound insulation cotton layer; 12. Sound insulation layer; 13. First aluminum foil; 14. Foamed aluminum; 15. Second aluminum foil. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," and "connected," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0027] Example 1:

[0028] As shown in Figures 1-3 of the specification, a silencing structure for a fresh air system duct includes a duct body 1 and a silencing component. The silencing component includes multiple silencing units 2 spaced apart along the axial direction of the duct body 1. Each silencing unit 2 is composed of a support frame 3, a porous sound-absorbing layer 4, a resonant cavity array 5, and a flow guide cone 6. The spacing between adjacent silencing units 2 is one time the diameter of the duct. The outer wall of the duct is provided with a sound insulation layer 12, which has a three-layer structure from the inside to the outside: a first aluminum foil 13, aluminum foam 14, and a second aluminum foil 15.

[0029] In this utility model, the support frame 3 has the same shape as the inner wall of the pipe body 1 and is fixed to the inner wall of the pipe body 1. An elastic vibration isolation pad 10 is provided between the support frame 3 and the inner wall of the pipe. The vibration isolation pad is made of EPDM rubber.

[0030] In this utility model, the porous sound-absorbing layer 4 is attached to the inner side of the support frame 3. The porous sound-absorbing layer 4 has a gradient density structure and is provided with multiple sound-absorbing holes 8. The porosity of the sound-absorbing holes 8 gradually increases and the density gradually decreases along the airflow direction.

[0031] In this utility model, the resonant cavity array 5 is located on both sides of the porous sound-absorbing layer 4, and the support frame 3 is provided with corresponding slots 7 at the porous sound-absorbing layer 4. The two ends of the resonant cavity array 5 are respectively fixed to the slots 7 of the adjacent support frame 3. The resonant cavity array 5 is composed of multiple independent cavities arranged in a honeycomb pattern, and the neck opening diameter of each cavity in the resonant cavity array 5 is 5mm. The resonant cavity array 5 and the pipe body 1 are filled with a sound insulation cotton layer 11.

[0032] In this utility model, the flow guide cone 6 is located in the central region of the porous sound-absorbing layer 4, with its cone apex pointing in the direction of airflow. The cone angle of the flow guide cone 6 decreases by 5 degrees along the direction of airflow, and the minimum cone angle is 5 degrees.

[0033] As shown in Figure 4 of the instruction manual, the surface of the guide cone 6 is provided with a spiral guide groove 9 with a spiral angle of 20 degrees, which is used to guide the airflow along the spiral path, destroy the conditions for the formation of turbulent vortices, and reduce the generation of secondary noise.

[0034] Working principle

[0035] When fresh air is transported through the duct, the noise reduction structure achieves noise reduction through the following process:

[0036] 1. Airflow guidance and turbulence suppression: The airflow first contacts the variable cone angle guide cone 6, and the tapered structure at the cone tip pointing in the direction of the airflow reduces the inlet resistance; the spiral guide groove 9 on the surface of the cone guides the airflow along the spiral path, destroying the conditions for the formation of turbulent vortices and reducing the generation of secondary noise;

[0037] 2. Porous sound-absorbing layer 4 broadband absorption: After the airflow enters the porous sound-absorbing layer 4, the sound waves enter the interior of the material through the sound-absorbing holes 8, and are converted into heat energy by friction with the hole walls and vibration of material molecules. The gradient density structure enables the outer layer to preferentially absorb mid-to-high frequency noise (2000Hz-5000Hz), while the inner layer focuses on absorbing mid-to-low frequency noise (500Hz-2000Hz), achieving full-band coverage.

[0038] 3. Low-frequency attenuation of resonant cavity array 5: Low-frequency sound waves (200Hz-500Hz) that are not fully absorbed are transmitted to the honeycomb resonant cavity array 5. The opening at the neck of the cavity resonates with the sound waves, and the energy is consumed through friction on the cavity wall. The sound insulation cotton layer 11 further supplements the sound absorption coefficient in the low-frequency range (<500Hz) and improves the overall noise reduction effect.

[0039] 4. Vibration isolation and solid-borne sound blocking: The elastic vibration isolation pad 10 between the support frame 3 and the pipe absorbs the structural vibration energy and reduces the transmission of vibration to the pipe wall; the aluminum foil-foamed aluminum 14-aluminum foil composite sound insulation layer 12 on the outer wall of the pipe blocks the radiation of solid-borne sound (such as low-frequency noise caused by pipe vibration) through the mass law (the aluminum foil increases the surface density) and the porous sound absorption characteristics of foamed aluminum 14.

[0040] The present invention and its embodiments have been described above. This description is not restrictive, and the specific embodiments shown are only one of the embodiments of the present invention. The actual structure is not limited to this. In short, if a person skilled in the art is inspired by this description and designs a similar structure and embodiment without departing from the inventive spirit of the present invention, such design should fall within the protection scope of the present invention.

Claims

1. A silencing structure for a fresh air system duct, comprising a duct body (1) and a silencing component, characterized in that: The silencing assembly includes multiple silencing units (2) spaced apart along the axial direction of the pipe body (1). Each silencing unit (2) is composed of a support frame (3), a porous sound-absorbing layer (4), a resonant cavity array (5), and a flow guide cone (6). The support frame (3) has the same shape as the inner wall of the pipe body (1) and is fixed to the inner wall of the pipe body (1). The porous sound-absorbing layer (4) is attached to the inner side of the support frame (3). The resonant cavity array (5) is located on both sides of the porous sound-absorbing layer (4), and the support frame (3) is provided with corresponding slots (7) at the outlet of the porous sound-absorbing layer (4). The two ends of the resonant cavity array (5) are fixed to the slots (7) of the adjacent support frame (3). The flow guide cone (6) is located in the central area of ​​the porous sound-absorbing layer (4), and its cone tip points in the direction of airflow.

2. The silencing structure for a fresh air system duct according to claim 1, characterized in that: The resonant cavity array (5) is composed of multiple independent cavities arranged in a honeycomb pattern, and the neck opening diameter of each cavity in the resonant cavity array (5) is in the range of 3-8 mm.

3. The silencing structure for a fresh air system duct according to claim 1, characterized in that: The porous sound-absorbing layer (4) has a gradient density structure and multiple sound-absorbing holes (8) are provided on it. The porosity of the sound-absorbing holes (8) gradually increases and the density gradually decreases along the airflow direction.

4. The silencing structure for a fresh air system duct according to claim 1, characterized in that: The spacing between adjacent silencing units (2) is 0.8 to 1.2 times the pipe diameter.

5. The silencing structure for a fresh air system duct according to claim 1, characterized in that: The cone angle of the guide cone (6) decreases by 5-10 degrees along the airflow direction, with the minimum cone angle being 5 degrees.

6. The silencing structure for a fresh air system duct according to claim 1, characterized in that: The surface of the guide cone (6) is provided with a spiral guide groove (9) with a spiral angle of 15 degrees to 30 degrees.

7. The silencing structure for a fresh air system duct according to claim 1, characterized in that: An elastic vibration isolation pad (10) is provided between the support frame (3) and the inner wall of the pipe. The vibration isolation pad is made of EPDM rubber.

8. The silencing structure for a fresh air system duct according to claim 1, characterized in that: The resonant cavity array (5) and the pipe body (1) are filled with a sound-insulating cotton layer (11).

9. The silencing structure for a fresh air system duct according to claim 1, characterized in that: The outer wall of the pipe is provided with a sound insulation layer (12), which consists of a three-layer structure from the inside to the outside of a first aluminum foil (13), aluminum foam (14), and a second aluminum foil (15).

Images