Silencer air duct

Abstract

The silencing air pipe comprises a pipe shell and a flow guide body, the pipe shell has a front pipe, a middle pipe and a tail pipe, a plurality of flow guide holes are arranged in the front pipe, the inner wall of the middle pipe near one end of the front pipe has a first conical surface, the inner wall of the middle pipe near one end of the tail pipe has a second conical surface, the first conical surface and the second conical surface are coaxial with the pipe shell, a plurality of through holes are densely arranged on the side wall of the tail pipe, a sound absorption layer is arranged on the outer wall of the tail pipe, the outer part of the flow guide body is a cylindrical structure, the front end of the flow guide body has an outer conical surface, the flow guide body is coaxially arranged in the tail pipe, a gap is formed between the outer wall of the flow guide body and the inner wall of the tail pipe, the rear end of the flow guide body is directed to the rear end of the tail pipe, the outer conical surface is arranged in the middle pipe, and the outer conical surface is located at the same position as the second conical surface in the axial direction of the pipe shell, and the projection of the flow guide hole and the outer conical surface in the axial direction of the pipe shell partially overlaps.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of the sound attenuation air pipe structure, especially relates to a sound attenuation air pipe. BACKGROUND

[0002] The pipeline is more widely applied in various gas delivery and recovery, but the gas flow in the pipeline process, because of the impact of airflow, it is easy to produce larger noise, causes noise pollution to the workshop and factory periphery. In order to solve the above-mentioned noise problem, the existing scheme is wrapped in the pipeline outside sound attenuation cotton, for absorbing part noise, but the sound attenuation means of this kind of way is relatively single, and the sound attenuation effect is poor. INVENTION CONTENTS

[0003] In order to solve the technical problems of the prior art, the utility model provides a sound attenuation air pipe, which has multiple sound attenuation structures, and can effectively reduce the noise radiated outward during gas transmission.

[0004] In order to achieve the purpose of the utility model, the following scheme is adopted:

[0005] A sound attenuation air pipe, comprising: a pipe shell and a flow guide body;

[0006] The pipe shell has a front pipe, a middle pipe and a tail pipe arranged coaxially in sequence, and the gas flows from the front pipe to the tail pipe;

[0007] A plurality of flow guide holes are arranged in the front pipe along the circumference, and the flow guide holes are parallel to the pipe shell;

[0008] The inner diameter of the middle pipe is greater than that of the front pipe and the tail pipe, the inner wall of the middle pipe near the front pipe end has a first conical surface, the first conical surface is inclined towards the tail pipe, the inner wall of the middle pipe near the tail pipe end has a second conical surface, the second conical surface is inclined towards the front pipe, and the first conical surface and the second conical surface are coaxial with the pipe shell;

[0009] A plurality of through holes are densely arranged on the side wall of the tail pipe, and a sound absorbing layer is arranged on the outer wall of the tail pipe;

[0010] The outer part of the flow guide body is a cylindrical structure, the front end of the flow guide body has an outer conical surface, the flow guide body is coaxially arranged in the tail pipe, there is a gap between the outer wall of the flow guide body and the inner wall of the tail pipe for forming an annular cavity, the rear end of the flow guide body is directed towards the rear end of the tail pipe, the outer conical surface is located in the middle pipe, and the outer conical surface and the second conical surface are located at the same position in the axial direction of the pipe shell;

[0011] The projection of the flow guide hole and the outer conical surface in the axial direction of the pipe shell partially overlaps.

[0012] The utility model has the advantages that multiple sound attenuation structures are arranged, which can comprehensively eliminate high, medium and low frequency noise, have better sound attenuation effect, and can effectively reduce the noise transmitted outward through the pipeline during gas transmission. Attached Figure Description

[0013] The accompanying drawings described herein are merely illustrative of selected embodiments, not all possible implementations, and are not intended to limit the scope of this invention.

[0014] Figure 1 A schematic diagram of the exhaust end of the silencer duct of this application is shown.

[0015] Figure 2 A schematic diagram of the air inlet end of the silencer duct of this application is shown.

[0016] Figure 3 A cross-sectional view of a preferred structure of the silencer duct of this application is shown.

[0017] Figure 4 It shows Figure 3 A magnified view of a portion of point A in the middle.

[0018] The markings in the diagram are: shell-1, front tube-11, middle tube-12, first conical surface-121, second conical surface-122, tail tube-13, through hole-131, cylinder-2, guide hole-21, sound-absorbing layer-3, guide fluid-4, outer conical surface-41, ring-42, rib-43, conical ring-44, extension rod-45. Detailed Implementation

[0019] To make the objectives, technical solutions and advantages of the embodiments of this utility model clearer, the implementation methods of this utility model will be described in detail below with reference to the accompanying drawings. However, the examples described in this utility model are only some embodiments of this utility model, and not all embodiments.

[0020] like Figures 1 to 3 As shown, a sound-absorbing duct includes: a duct shell 1 and a fluid guide 4.

[0021] The shell 1 has a front tube 11, a middle tube 12 and a tail tube 13 arranged coaxially in sequence, and the gas flows from the front tube 11 to the tail tube 13.

[0022] Multiple flow guide holes 21 are arranged in a circular array along the inner edge of the front tube 11, and the flow guide holes 21 are parallel to the tube shell 1.

[0023] The inner diameter of the middle tube 12 is larger than the inner diameter of the front tube 11 and the tail tube 13. The inner wall of the middle tube 12 near the front tube 11 has a first conical surface 121, which is inclined toward the tail tube 13. The inner wall of the middle tube 12 near the tail tube 13 has a second conical surface 122, which is inclined toward the front tube 11. Both the first conical surface 121 and the second conical surface 122 are coaxial with the tube shell 1.

[0024] The tailpipe 13 has multiple through holes 131 densely arranged on its side wall, and a sound-absorbing layer 3 is fitted on the outer wall of the tailpipe 13.

[0025] The outer part of the guide fluid 4 is a cylindrical structure with an outer conical surface 41 at its front end. The guide fluid 4 is coaxially inserted into the tail tube 13. There is a gap between the outer wall of the guide fluid 4 and the inner wall of the tail tube 13 to form an annular cavity. The rear end of the guide fluid 4 faces the rear end of the tail tube 13. The outer conical surface 41 is located inside the middle tube 12, and the outer conical surface 41 and the second conical surface 122 are aligned in the axial direction of the tube shell 1.

[0026] The projections of the flow guide hole 21 and the outer conical surface 41 onto the axis of the tube shell 1 partially overlap.

[0027] The sound-absorbing duct with the above structure, after the airflow enters the front pipe 11 from the front section of the pipe shell 1, the cross section of the pipe corresponding to the front and rear ends of the front pipe 11 is changed by the guide hole 21 and the middle pipe 12 with a larger inner diameter. This causes the sound generated by the airflow to change the impedance during propagation, resulting in sound energy interference, thereby reducing the sound energy radiated to the outside of the pipe, so as to reduce noise. This method is mainly used to reduce mid- and low-frequency noise.

[0028] like Figure 3 As shown by the solid arrow, after the airflow enters the middle tube 12 through the guide hole 21, part of the airflow will flow directly into the annular cavity, while the other part of the airflow will impact the outer conical surface 41, as shown by the arrow. Figure 3 As shown by the dashed arrow, the outer conical surface 41 reflects part of the sound energy generated by the airflow. The reflected sound energy will interfere with the sound energy of the airflow that directly enters the annular cavity, thereby further improving the noise reduction effect. The reflected sound energy will be reflected in sequence by the second conical surface 122 and the first conical surface 121, and will continue to interfere with the sound energy of the airflow discharged from the guide hole 21, so as to further improve the noise reduction effect. The airflow that comes into contact with the outer conical surface 41 will eventually flow into the annular cavity after the pressure inside the middle tube 12 increases.

[0029] After the airflow enters the annular cavity, some of the sound waves are conducted to the sound-absorbing layer 3 through the through hole 131. During the propagation of the sound waves inside the sound-absorbing layer 3, the sound energy is converted into heat energy due to friction and dissipated, so that the noise propagating along the pipe is attenuated with distance, thereby achieving the purpose of noise reduction. This kind of noise reduction structure is mainly used to eliminate mid-to-high frequency noise.

[0030] The above methods can comprehensively eliminate high, medium, and low frequency noise, resulting in a better noise reduction effect and effectively reducing the noise transmitted outward through the pipeline during gas transmission.

[0031] Preferred, such as Figure 2 , Figure 3As shown, a detachable cylinder 2 is coaxially inserted inside the front tube 11, and a flow guide hole 21 is opened on the cylinder 2 to reduce the manufacturing difficulty of the tube shell 1 and facilitate replacement after the inner wall of the flow guide hole 21 is worn.

[0032] Preferred, such as Figure 3 As shown, a ring 42 is coaxially provided on the outer side of the rear end of the guide fluid 4. The inner diameter of the ring 42 is the same as the inner diameter of the tail pipe 13. A countersunk hole is provided at the end of the tail pipe 13 for installing the ring 42. The ring 42 and the guide fluid 4 are connected by multiple ribs 43. With the above structure, the guide fluid 4 can be coaxially installed in the tail pipe 13, and a predetermined distance is ensured between the guide fluid 4 and the inner wall of the tail pipe 13. The ring 42 is locked to the tail pipe 13 with screws. Alternatively, when installing the silencer duct, the end face of the pipe connected to the pipe shell 1 can be used to press the ring 42 into the countersunk hole.

[0033] Preferred, such as Figure 3 As shown, the front end of the fluid guide 4 is coaxially provided with an extension rod 45, which passes through the cylinder 2 to improve the installation stability of the fluid guide 4 and prevent the front end of the fluid guide 4 from generating large-amplitude vibrations.

[0034] Preferably, the fluid guide 4 has a hollow structure to reduce the overall weight of the silencer duct.

[0035] Specifically, flanges are provided at both ends of the casing 1 to facilitate installation and connection. The front pipe 11, the middle pipe 12, and the tail pipe 13 are all circular pipe structures.

[0036] Preferably, the sound-absorbing layer 3 is made of centrifugal glass wool or asbestos, and the sound-absorbing layer 3 is covered with a metal shell, which protects the sound-absorbing layer 3.

[0037] Preferred, such as Figure 4 As shown, a conical ring 44 is coaxially provided on the outer wall of the guide fluid 4, with its cone apex facing the front end of the guide fluid 4. There is a gap between the large end edge of the conical ring 44 and the inner wall of the tail pipe 13. The conical ring 44 can guide the airflow to flow towards the inner wall of the tail pipe 13, so that the sound energy generated by the airflow can also flow to the side wall of the tail pipe 13, thereby increasing the probability of sound energy entering the sound-absorbing layer 3 and thus improving the noise reduction effect.

[0038] The above description is merely a preferred embodiment of this utility model and does not imply its uniqueness or limitation. Those skilled in the art should understand that various changes or equivalent substitutions made to this utility model without departing from its scope are all within the protection scope of this utility model.

Claims

1. A sound attenuating air duct characterized by, The utility model relates to a sound absorption device, including: A pipe shell (1) and a flow guide body (4); The pipe shell (1) has a front pipe (11), a middle pipe (12) and a tail pipe (13) arranged coaxially in sequence, and gas flows from the front pipe (11) to the tail pipe (13); A plurality of flow guide holes (21) are arranged in an array along the circumference in the front pipe (11), and the flow guide holes (21) are parallel to the pipe shell (1); The inner diameter of the middle pipe (12) is greater than the inner diameters of the front pipe (11) and the tail pipe (13), the inner wall of the middle pipe (12) near one end of the front pipe (11) has a first conical surface (121), the first conical surface (121) is inclined towards the tail pipe (13), the inner wall of the middle pipe (12) near one end of the tail pipe (13) has a second conical surface (122), the second conical surface (122) is inclined towards the front pipe (11), and the first conical surface (121) and the second conical surface (122) are coaxial with the pipe shell (1); A plurality of through holes (131) are densely arranged on the side wall of the tail pipe (13), and a sound absorption layer (3) is arranged on the outer wall of the tail pipe (13); The flow guide body (4) has a cylindrical structure, the front end of the flow guide body (4) has an outer conical surface (41), the flow guide body (4) is coaxially arranged in the tail pipe (13), there is a gap between the outer wall of the flow guide body (4) and the inner wall of the tail pipe (13) for forming an annular cavity, the rear end of the flow guide body (4) is directed towards the rear end of the tail pipe (13), the outer conical surface (41) is located in the middle pipe (12), and the outer conical surface (41) is located at the same position as the second conical surface (122) in the axial direction of the pipe shell (1); The projection of the flow guide hole (21) and the outer conical surface (41) in the axial direction of the pipe shell (1) partially overlaps.

2. A sound attenuating air duct according to claim 1, wherein A detachable cylinder (2) is coaxially arranged in the front pipe (11), and the flow guide hole (21) is arranged on the cylinder (2).

3. A sound attenuating air duct according to claim 2, wherein An annular ring (42) is coaxially arranged on the rear end of the flow guide body (4), the inner diameter of the annular ring (42) is the same as the inner diameter of the tail pipe (13), a counterbore is arranged at the tail end of the tail pipe (13) for mounting the annular ring (42), and the annular ring (42) is connected to the flow guide body (4) by a plurality of ribs (43).

4. A sound attenuating air duct according to claim 3, wherein An extension rod (45) is coaxially arranged on the front end of the flow guide body (4) and arranged in the cylinder (2).

5. A sound attenuating air duct according to claim 1, wherein The flow guide body (4) has a hollow structure.

6. A sound attenuating air duct according to claim 1, wherein Flanges are arranged at both ends of the pipe shell (1).

7. A sound attenuating air duct according to claim 1, wherein The front pipe (11), the middle pipe (12) and the tail pipe (13) all have a circular pipe structure.

8. A sound attenuating air duct according to claim 1, wherein The sound absorption layer (3) is made of centrifugal glass wool or asbestos, and a metal shell is arranged on the outer part of the sound absorption layer (3).

9. A sound attenuating air duct according to claim 1, wherein A conical ring (44) is coaxially arranged on the outer wall of the flow guide body (4), the tip of the conical ring (44) is directed towards the front end of the flow guide body (4), and there is a gap between the large end edge of the conical ring (44) and the inner wall of the tail pipe (13).

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