Chimney hood muffler

Abstract

The present invention discloses a chimney hood silencer, including a hood structure, a silencer component and a mounting platform. The hood structure includes a hood shell, a load-bearing structure and a vibration-damping pad. The hood shell is composed of an upper umbrella cap and a lower cylinder. A sound-absorbing plate is arranged inside the hood shell to form a sound-absorbing umbrella cap for inner sound absorption and an outer cylinder sound-absorbing body. The silencer component includes an inner cylinder sound-absorbing body whose inner diameter is the sound-isolating plate and whose outer diameter is the sound-absorbing plate, and a cylindrical sound-absorbing body whose inner diameter and outer diameter are both the sound-absorbing plate. The mounting platform is arranged outside the exhaust pipe orifice, and the upper part is flush with the plane of the orifice. The inner cylinder sound-absorbing body is on the exhaust pipe orifice. The inner diameter of the sound-isolating plate of the inner cylinder sound-absorbing body is consistent with the inner diameter of the exhaust pipe. The outer cylinder sound-absorbing body, the cylindrical sound-absorbing body and the inner cylinder sound-absorbing body are installed vertically, and the bottoms are all on the same horizontal plane. A concentric circular silencer channel is formed between the silencer components, and the air outlet direction of the silencer channel is opposite to the air outlet direction of the exhaust pipe.

Description

Technical Field

[0001] The invention relates to a muffler, in particular to a chimney cap muffler installed at an air outlet of an exhaust chimney. Background Art

[0002] This includes boiler steam emissions from industries such as petroleum, chemical, metallurgy, and textiles, as well as emissions from other exhaust pipes. This causes the fan and equipment noise to be radiated through the exhaust pipe outlet. Since the exhaust pipe is located higher than the surrounding buildings and there is no effective barrier to block it, the noise affects the environment in a considerable range around it, which has a great impact on noise-sensitive points. Therefore, the current practice is to install a muffler first to reduce the noise before discharging it into the chimney. However, if there is no reserved space for a muffler in the equipment room, it will be difficult to achieve a noise reduction effect.

[0003] If a large chimney silencer is installed on the upper part of the exhaust pipe, the noise reduction design requirements can be met. However, the increased weight will affect the exhaust pipe design load, and the increased windward area will increase the impact of gusts. If the exhaust pipe is re-evaluated and reinforced, it will incur a considerable cost for noise control. The exhaust pipe of industrial enterprises is the main factor that causes excessive noise at the factory boundary. Summary of the invention

[0004] In order to overcome the influence of the existing fan and equipment noise radiated through the exhaust pipe outlet, the present invention provides a chimney cap muffler, which can not only meet the requirements of eliminating the aerodynamic noise radiated from the exhaust pipe outlet, but also has the advantages of small size, small windward surface, light weight, easy installation, low cost, etc. At the same time, it has the characteristics of high temperature resistance, airflow impact resistance, corrosion resistance and oil mist resistance, and small airflow resistance loss.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a chimney hood silencer includes a hood structure, a silencer component and a mounting platform, the hood structure includes a hood shell, a load-bearing structure, and a vibration-damping pad, the hood shell is composed of an upper umbrella cap and a lower cylinder, a sound-absorbing plate is arranged inside the hood shell to form a sound-absorbing umbrella cap for inner sound absorption and an outer cylinder sound-absorbing body, and the silencer component includes an inner cylinder sound-absorbing body whose inner diameter is the sound insulation board and the outer diameter is the sound absorption board, and a cylindrical sound-absorbing body whose inner diameter and outer diameter are both the sound absorption board. The mounting platform is arranged outside the exhaust pipe orifice, the upper part is flush with the plane of the pipe orifice, the inner cylinder sound-absorbing body is on the exhaust pipe orifice, the inner diameter of the sound insulation board of the inner cylinder sound-absorbing body is consistent with the inner diameter of the exhaust pipe, the outer cylinder sound-absorbing body, the cylindrical sound-absorbing body, and the inner cylinder sound-absorbing body are installed vertically, and the bottoms are all on the same horizontal plane, and a concentric circular silencer channel is formed between the silencer components, and the air outlet direction of the silencer channel is opposite to the air outlet direction of the exhaust pipe. The fan noise is dissipated to the surrounding space through the exhaust pipe orifice. Multiple annular air outlet silencer channels allow the fan noise to pass through the sound-absorbing umbrella cap and the annular silencer channel to form an impedance silencer structure. There is no direct channel for noise, which eliminates the high-frequency failure of noise, increases the silencer ratio of low-frequency noise, effectively increases the silencer volume, and has a full-frequency silencer function. The silencer channel exhausts air toward the ground around the exhaust pipe, and the noise propagation angle through the silencer channel forms a 90° angle with the direction of the noise sensitive point. The influence range of the exhaust noise is reduced, and the silencer and noise reduction effect is improved.

[0006] The sound absorbing board is a pinhole composite aluminum sound absorbing board, the inner cavity of the single-sided sound absorbing board is 0.05m-0.075m, the inner cavity of the double-sided sound absorbing board is 0.10m, and the width of the sound absorbing channel is 0.15mm-0.25mm. The composite pinhole sound absorbing board has the characteristics of high temperature resistance, air flow impact resistance, corrosion resistance and oil mist resistance, and small air flow resistance loss. It can be used in various types of boilers and steam turbine exhaust in industrial factories and mines such as power generation, chemical industry, metallurgy, and textiles. Reducing the thickness of the cylindrical sound absorbing body can increase the number of cylindrical sound absorbing bodies, increase the air flow channel of the cylindrical sound absorbing body, reduce the air flow velocity, and reduce the wind pressure loss. The smaller the distance between the cylindrical sound absorbing bodies, the larger the effective contact area between the sound absorbing material and the sound wave, which will increase the number of reflections of the sound wave in the channel between the sheets, that is, increase the contact opportunity between the sound wave and the sound absorbing material. The smaller the cross-section of each small channel, the greater the sound absorption amount.

[0007] The air outlet channel between the inner diameter of the soundproof board of the inner cylindrical sound absorber and the sound absorbing umbrella cap is more than 125% of the cross-sectional area of ​​the exhaust pipe orifice, and the effective area of ​​the annular silencer channel is more than 175% of the cross-sectional area of ​​the exhaust pipe orifice. The number and specifications of the cylindrical sound absorbers are determined according to the exhaust pipe diameter and the wind speed in the pipe. From the exhaust pipe → the inside of the sound absorbing umbrella cap → the silencer channel, the airflow velocity is gradually reduced, the airflow pressure loss is reduced, and the sound reduction effect is improved. According to the requirements of wind pressure, air volume and noise control, the height and width of the silencer channel can be adjusted accordingly.

[0008] The horizontal angle of the umbrella cap is 20 degrees, and the distance between the inner diameter top of the sound insulation board of the inner cylindrical sound absorbing body and the sound absorbing board of the sound absorbing umbrella cap is 32% to 37% of the inner diameter of the exhaust pipe. The effective area between the top of the inner sound absorbing cylinder and the sound absorbing umbrella cap can be greater than the effective area of ​​the chimney outlet, and the height of the chimney cap silencer can be minimized, and the windward area and gust load of the chimney cap silencer can be reduced under the premise of reducing the air flow velocity and reducing the air flow pressure loss.

[0009] The height of the inner cylindrical sound absorber is 0.5 to 1.0 m, the height of the outer cylindrical sound absorber is higher than that of the inner cylindrical sound absorber, and the height of the multiple cylindrical sound absorbers increases from the inside to the outside according to the relative positions, and the width of the sound absorption channel increases from the inside to the outside. The sound absorption effect decreases as the effective sound absorption length decreases. In order to ensure the same sound absorption effect of the air outlet sound absorption channel, reducing the width of the air outlet sound absorption channel can offset the effect of reducing the effective sound absorption length.

[0010] An elastic vibration-damping pad is arranged between the hood structure and the mounting platform, and the gap between the sound insulation board of the inner cylindrical sound-absorbing body and the exhaust pipe opening is filled with an elastic sound insulation material.

[0011] The beneficial effects of the present invention are: it can not only be used on the exhaust outlets of various fans, ventilators, etc. to reduce the aerodynamic noise of the tuyere, but also can be used for the high-temperature, corrosive and oil mist gases discharged from boiler steam and other exhaust pipes. It has a wide anechoic spectrum, small airflow pressure loss, small windward surface, light weight, and little impact on the gravity load and gusts of the chimney exhaust pipe, and no foundation reinforcement is required.

[0012] The present invention is further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a front cross-sectional structural diagram of the first embodiment of the present invention.

[0014] Figure 2 yes Figure 1 Top view of the .

[0015] Figure 3 It is a front cross-sectional structural diagram of the second embodiment of the present invention.

[0016] In the figure, 1. hood structure, 11. umbrella cap, 12. cylinder, 13. lifting ring, 14. vibration damping pad, 2. sound-absorbing component, 21. sound-absorbing board, 22. sound-absorbing umbrella cap, 23. outer cylinder sound-absorbing body, 24. sound insulation board, 25. inner cylinder sound-absorbing body, 26. cylindrical sound-absorbing body, 27. sound-absorbing channel, 3. installation platform, 4. exhaust pipe, 41. pipe mouth, 42. pipe wall, 43. elastic sound insulation material.

[0017] The specific implementation is Figure 1 , 2 In the first embodiment shown, the hood structure (1), a sound-absorbing component (2) and a mounting structure are included. The hood structure (1) includes a hood shell, a load-bearing structure, a mounting ring (13) and a vibration-damping pad (14). The hood shell is composed of an upper umbrella cap (11) and a lower cylindrical body (12). A sound-absorbing plate (21) is arranged on the inner side of the hood shell to form a sound-absorbing umbrella cap (22) for inner sound absorption and an outer cylindrical sound-absorbing body (23). An inner cylindrical sound-absorbing body (24) for inner sound insulation and outer sound absorption is arranged inside the outer cylindrical sound-absorbing body (23). The sound-absorbing component (2) includes an inner cylindrical sound-absorbing body (25) whose inner diameter is the sound-absorbing plate (24) and whose outer diameter is the sound-absorbing plate (21), and a cylindrical sound-absorbing body (26) whose inner diameter and outer diameter are both the sound-absorbing plate (21). The mounting platform (3) is arranged outside the outlet (41) of the exhaust pipe (4), with the upper portion being flush with the plane of the outlet (41); the inner cylindrical sound absorber (25) is on the outlet (41) of the exhaust pipe (4); the inner diameter of the sound insulation board (24) of the inner cylindrical sound absorber (25) is consistent with the inner diameter of the exhaust pipe (4); the outer cylindrical sound absorber (23), the cylindrical sound absorber (26), and the inner cylindrical sound absorber (25) are vertically mounted, with the bottoms all being on the same horizontal plane; a concentric circular sound absorption channel (27) is formed between the sound absorption components (2); and the air outlet direction of the sound absorption channel (27) is opposite to the air outlet direction of the exhaust pipe (4).

[0018] The sound absorbing plate (21) is a pinhole composite aluminum sound absorbing plate (21), the inner cavity of the single-sided sound absorbing plate (21) is 0.05m to 0.075m, the inner cavity of the double-sided sound absorbing plate (21) is 0.10m, and the width of the silencer channel (27) is 0.15m to 0.25m.

[0019] The air outlet passage between the inner diameter of the sound insulation board (24) of the inner cylindrical sound absorber (25) and the sound absorbing umbrella cap (22) is more than 125% of the cross-sectional area of ​​the pipe opening (41) of the exhaust pipe (4), the effective area of ​​the annular sound-absorbing passage (27) is more than 175% of the cross-sectional area of ​​the pipe opening (41) of the exhaust pipe (4), and the number of cylindrical sound absorbers (26) is determined according to the diameter of the exhaust pipe (4) and the air outlet volume.

[0020] The horizontal angle of the umbrella cap (11) is 20 degrees, and the distance between the top of the inner diameter of the sound insulation board (24) of the inner cylindrical sound absorber (25) and the sound absorbing board (21) of the sound absorbing umbrella cap (22) is 32% to 37% of the inner diameter of the exhaust pipe (4).

[0021] The height of the inner cylindrical sound absorber (25) is 0.5 to 1.0 m, the height of the outer cylindrical sound absorber (23) is higher than the inner cylindrical sound absorber (25), the heights of the plurality of cylindrical sound absorbers (26) increase from the inside to the outside according to their relative positions, and the width of the silencer channel (27) increases from the inside to the outside.

[0022] An elastic vibration-damping pad (14) is arranged between the hood structure (1) and the mounting platform (3), and the gap between the sound insulation board (24) of the inner cylindrical sound absorbing body (25) and the pipe opening (41) of the exhaust pipe (4) is filled with an elastic sound insulation material.

[0023] exist Figure 3 In the second embodiment shown, the diameter of the exhaust pipe (4) is relatively small, the air output is relatively small, and no cylindrical sound absorber (26) is provided between the outer cylindrical sound absorber (23) and the inner cylindrical sound absorber (25).

[0024] The above embodiments are only used to further illustrate a chimney hood silencer of the present invention, but the present invention is not limited to the embodiments. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention fall within the protection scope of the technical solution of the present invention.

Claims

1. A chimney hood muffler, comprising a hood structure and a muffler component, wherein the hood structure comprises a hood shell and a load-bearing structure, and is characterized by: The outer shell of the hood is composed of an upper umbrella cap and a lower cylinder. A sound-absorbing plate is arranged on the inner side of the outer shell of the hood to form a sound-absorbing umbrella cap for inner sound absorption and an outer cylindrical sound-absorbing body. The sound-absorbing component includes an inner cylindrical sound-absorbing body whose inner diameter is the sound insulation board and outer diameter is the sound-absorbing board, and a cylindrical sound-absorbing body whose inner diameter and outer diameter are both the sound-absorbing board. The inner cylindrical sound-absorbing body is outside the exhaust pipe orifice, and the top is on the same horizontal plane as the exhaust pipe orifice. The air outlet channel between the inner diameter of the sound insulation board of the inner cylindrical sound-absorbing body and the sound-absorbing umbrella cap is more than 125% of the cross-sectional area of ​​the exhaust pipe orifice, and the effective area of ​​the annular sound-absorbing channel is more than 175% of the cross-sectional area of ​​the exhaust pipe orifice. Concentric annular sound-absorbing channels are formed between the sound-absorbing components, and the air outlet direction of the sound-absorbing channel is opposite to that of the exhaust pipe.

2. The chimney cap muffler according to claim 1, characterized in that: The sound absorbing board is a pinhole composite aluminum sound absorbing board, the inner cavity of the single-sided sound absorbing board is 0.05m-0.075m, the inner cavity of the double-sided sound absorbing board is 0.10m, and the width of the muffler channel is 0.15mm-0.25mm.

3. The chimney cap muffler according to claim 1, characterized in that: The outer cylindrical sound absorber, the cylindrical sound absorber and the inner cylindrical sound absorber are installed vertically, and their bottoms are all on the same horizontal plane. The number of the cylindrical sound absorbers is determined according to the exhaust pipe diameter and the air output.

4. The chimney cap muffler according to claim 1, characterized in that: The horizontal angle of the umbrella cap is 20 degrees, and the distance between the inner diameter top of the sound insulation board of the inner cylindrical sound absorber and the sound absorbing board of the sound absorbing umbrella cap is 32% to 37% of the inner diameter of the exhaust pipe.

5. The chimney cap muffler according to claim 1, characterized in that: The height of the inner cylindrical sound absorber is 0.5-1.0m, the height of the outer cylindrical sound absorber is higher than the inner cylindrical sound absorber, and the height of the multiple cylindrical sound absorbers increases from the inside to the outside according to their relative positions, and the width of the silencer channel increases from the inside to the outside.

6. The chimney cap muffler according to claim 1, characterized in that: An elastic vibration-damping pad is arranged between the hood structure and the mounting platform, and the gap between the sound insulation board of the inner cylindrical sound-absorbing body and the exhaust pipe opening is filled with an elastic sound insulation material.

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