A negative pressure machine muffler prepared from a composite sound attenuation material

Abstract

This utility model discloses a negative pressure compressor silencer made of composite sound-absorbing material, including a negative pressure fan body and a silencer pipe fixedly installed on the air inlet end of the negative pressure fan body. An air inlet channel is fixedly installed on the inner wall of the silencer pipe, and a primary noise reduction mechanism is provided on the inner wall of the air inlet channel near the pipe opening. The primary noise reduction mechanism includes an air inlet cylinder fixedly installed on the inner wall of the air inlet channel, and multiple air inlets are opened on the outer wall of the air inlet cylinder. This utility model, through the inner ring silencer cylinder, outer ring silencer cylinder, and silencer ring cylinder of the primary noise reduction mechanism forming a multi-stage sound absorption structure, utilizes the cooperation between the silencer holes and the annular cavity to allow sound waves to reflect and diffract between different cavities, effectively absorbing mid-to-high frequency noise. The coaxial and annular array distribution design of the air inlets guides the airflow to enter evenly, reducing the generation of eddy noise. The composite structure of the perforated metal cylinder and the sound insulation felt further blocks the transmission of noise, improving the broadband noise reduction effect.

Description

Technical Field

[0001] This utility model relates to the field of ventilation equipment technology, and more specifically, it relates to a negative pressure machine silencer made of composite sound-absorbing material. Background Technology

[0002] Negative pressure fans, commonly used in industrial ventilation, dust removal, and cooling, generate strong aerodynamic noise during operation due to the high-speed rotation of the impeller and the high-speed flow of air, severely impacting the working environment and equipment stability. Silencers are key components for reducing the noise of negative pressure fans, and their performance depends on the synergistic effect of sound-absorbing materials and structural design. Composite sound-absorbing materials, through combinations of various materials, can achieve efficient noise reduction across different frequency bands, representing an important technological direction for improving silencer performance and are widely used in industrial scenarios requiring noise control.

[0003] Currently, negative pressure compressor silencers on the market face multiple challenges in practical applications: some silencers have insufficient absorption efficiency for mid-to-high frequency noise, making it difficult to meet stringent noise reduction standards; when airflow enters the silencer, uneven distribution can easily generate eddy noise, exacerbating energy loss and noise pollution; some silencer structures are inconvenient to maintain, and after long-term use, the silencer materials are easily affected by dust and moisture, leading to a decline in performance and a reduction in the overall noise reduction effect of the equipment. Therefore, we propose a negative pressure compressor silencer made of composite silencer materials to solve the above problems. Utility Model Content

[0004] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide a negative pressure machine silencer made of composite sound-absorbing material.

[0005] To solve the above-mentioned technical problems, this utility model is achieved through the following technical solution:

[0006] This utility model is a negative pressure machine silencer made of composite sound-absorbing material, including a negative pressure fan body and a sound-absorbing pipe fixedly installed on the air inlet end of the negative pressure fan body. An air inlet channel is opened on the inner side wall of the sound-absorbing pipe, and a primary sound-absorbing mechanism is provided on the inner side wall of the air inlet channel near the pipe opening.

[0007] The initial silencing mechanism includes an air inlet duct fixedly installed on the inner wall of the air inlet channel. Multiple air inlets are provided on the outer wall of the air inlet duct. An inner annular groove and an outer annular groove are provided on the inner wall of the air inlet duct. An inner annular silencer is slidably connected to the inner wall of the inner annular groove, and an outer annular silencer is slidably connected to the inner wall of the outer annular groove. Both the inner and outer annular silencers have annular cavities inside. Multiple silencing holes are provided on both the outer and inner walls of the inner and outer annular silencers. The annular cavities and silencing holes are interconnected. A silencing ring is fixedly installed on the inner wall of the annular cavity. A sealing cap is fixedly installed at the end of the air inlet duct, and multiple air outlets are provided on the outer wall of the sealing cap.

[0008] In a preferred embodiment of this invention, the air inlet duct and the sealing cover are fixed together by multiple bolts.

[0009] As a preferred embodiment of this utility model, the air inlet and the air inlet duct located in the middle are coaxially arranged, and a plurality of air inlets are distributed in a ring array on the end of the air inlet duct.

[0010] As a preferred embodiment of this utility model, the air inlet, inner ring groove and outer ring groove are coaxially arranged, and the air inlet and air outlet on the same side are coaxially arranged.

[0011] As a preferred technical solution of this utility model, the material of the sound-absorbing ring cylinder is glass wool.

[0012] As a preferred embodiment of this utility model, a perforated metal cylinder is fixedly installed on the inner wall of the air inlet channel, the air inlet cylinder is fixedly installed on the inner wall of the perforated metal cylinder, and sound insulation felt is filled between the inner wall of the silencing pipe and the outer wall of the perforated metal cylinder.

[0013] In a preferred embodiment of this invention, the distance between two adjacent silencing holes is the same.

[0014] The advantages of this utility model are:

[0015] 1. The inner ring silencer, outer ring silencer, and silencer ring cylinder of the primary noise reduction mechanism form a multi-stage sound absorption structure. By utilizing the cooperation between the silencer holes and the ring cavity, sound waves are reflected and diffracted between different cavities, effectively absorbing mid-to-high frequency noise. The coaxial and ring array distribution design of the air inlet guides the airflow to enter evenly, reducing the generation of eddy noise. The composite structure of the perforated metal cylinder and the sound insulation felt further blocks the transmission of noise and improves the broadband noise reduction effect.

[0016] 2. The detachable structure with bolted fastening facilitates the replacement of internal noise reduction components during maintenance, ensuring stable performance over long-term use. The equidistant distribution of noise reduction holes and the coaxial arrangement of all components ensure uniform sound wave scattering and avoid sound energy concentration. The overall structure balances noise reduction efficiency and airflow smoothness, making it suitable for high-load and complex noise environments of industrial negative pressure fans, effectively improving the equipment's noise control capabilities and practicality. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a negative pressure machine silencer made of a composite sound-absorbing material according to this utility model.

[0018] Figure 2 for Figure 1 Enlarged view of the structure at point A in the middle.

[0019] Figure 3This is a side sectional view of the air inlet duct in a negative pressure machine silencer made of a composite sound-absorbing material according to this utility model.

[0020] Figure 4 This is a front view of the silencing pipe in a negative pressure machine silencer made of a composite silencing material according to this utility model.

[0021] Reference numerals: 1. Negative pressure fan body; 2. Silencing duct; 3. Air inlet channel; 4. Air inlet casing; 5. Air inlet; 6. Inner ring groove; 7. Outer ring groove; 8. Inner ring silencer; 9. Outer ring silencer; 10. Annular cavity; 11. Silencing hole; 12. Silencing ring cylinder; 13. Sealing cover; 14. Air outlet; 15. Metal perforated cylinder; 16. Sound insulation felt. Detailed Implementation

[0022] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are for illustrative purposes only and are not intended to limit the scope of this utility model. The utility model is described in more detail below by way of example with reference to the accompanying drawings. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of this utility model.

[0023] Reference Figure 1-4 A negative pressure compressor silencer made of composite sound-absorbing material includes a negative pressure fan body 1 and a silencer duct 2 fixedly installed on the air inlet end of the negative pressure fan body 1. An air inlet channel 3 is formed on the inner wall of the silencer duct 2, and a primary silencer mechanism is provided on the inner wall of the air inlet channel 3 near the pipe opening. The primary silencer mechanism includes an air inlet cylinder 4 fixedly installed on the inner wall of the air inlet channel 3. Multiple air inlets 5 are formed on the outer wall of the air inlet cylinder 4. An inner annular groove 6 and an outer annular groove 7 are formed on the inner wall of the air inlet cylinder 4. The inner ring silencer 8 is slidably connected to the wall, and the outer ring silencer 9 is slidably connected to the inner wall of the outer ring groove 7. Both the inner ring silencer 8 and the outer ring silencer 9 have annular cavities 10 inside. Both the outer and inner walls of the inner ring silencer 8 and the outer ring silencer 9 have multiple silencing holes 11. The annular cavity 10 and the silencing holes 11 are connected. A silencer ring cylinder 12 is fixedly installed on the inner wall of the annular cavity 10. A sealing cover 13 is fixedly installed at the end of the air inlet duct 4. Multiple air outlets 14 are opened on the outer wall of the sealing cover 13.

[0024] To further explain, the primary noise reduction mechanism within the air inlet channel 3 utilizes a three-layer nested structure of the air inlet duct 4, the inner ring silencer duct 8, and the outer ring silencer duct 9, in conjunction with the silencer ring duct 12 within the annular cavity 10 and multiple sets of silencer holes 11, to form a multi-stage resonant sound absorption system. When airflow enters through the air inlet 5, it is reflected and diffracted between different cavities, causing sound energy to be converted into heat energy and consumed in the porous material of the silencer ring duct 12, significantly improving the absorption efficiency of mid-to-high frequency noise. The staggered design of the air outlet 14 of the sealing cover 13 and the air inlet 5 extends the sound wave propagation path and enhances the noise reduction effect.

[0025] like Figure 2 As shown, the air inlet duct 4 and the sealing cover 13 are fixed together by multiple bolts.

[0026] To further explain, bolts facilitate disassembly, maintenance, or replacement of internal noise reduction components, thereby extending equipment lifespan and reducing operation and maintenance costs.

[0027] like Figure 2 and Figure 4 As shown, the air inlet 5 and the air inlet duct 4 in the middle are arranged coaxially, and multiple air inlets 5 are arranged in a ring array at the end of the air inlet duct 4.

[0028] To further explain, this design allows the remaining five air inlets to be distributed in a ring array, ensuring that the airflow is evenly dispersed into the primary noise reduction mechanism. This avoids the generation of vortex noise from localized high-speed airflow and optimizes the propagation path of sound waves between the cavities, thereby improving the uniformity of noise reduction.

[0029] like Figure 2 and Figure 3 As shown, the air inlet duct 4, the inner ring groove 6 and the outer ring groove 7 are arranged coaxially, and the air inlet 5 and the air outlet 14 on the same side are arranged coaxially.

[0030] To further explain, this design ensures the concentricity of each layer of sound-absorbing structure, allowing sound waves to be reflected uniformly within the annular cavity 10, thus reducing sound energy leakage; the coaxial design of the air inlet 5 and the air outlet 14 ensures smooth airflow while utilizing the reflection and superposition effect of sound waves in the coaxial channel to enhance the cancellation of noise at specific frequencies.

[0031] like Figure 2 and Figure 3 As shown, the material of the sound-absorbing ring cylinder 12 is glass wool.

[0032] To further explain, the porous structure of glass wool material provides excellent absorption performance for mid-to-high frequency noise, and it is also resistant to high temperatures (up to 200℃) and corrosion, making it suitable for the long-term operating environment of the negative pressure fan body 1 and ensuring the stability of the noise reduction effect.

[0033] like Figure 1 and Figure 2As shown, a perforated metal cylinder 15 is fixedly installed on the inner wall of the air inlet channel 3, and the air inlet duct 4 is fixedly installed on the inner wall of the perforated metal cylinder 15. Sound insulation felt 16 is filled between the inner wall of the silencing pipe 2 and the metal perforated cylinder 15 and the outer wall.

[0034] To further explain, the perforated metal cylinder 15 serves as a support structure, protecting the internal sound-absorbing components from airflow impact and absorbing noise in specific frequency bands through the principle of perforation resonance. The sound-absorbing felt 16 is filled between the sound-absorbing pipe 2 and the perforated metal cylinder 15, effectively blocking noise transmission and forming a composite noise reduction system of "sound absorption + sound insulation", which is especially effective against low-frequency noise and solid-borne sound transmission.

[0035] like Figure 2 As shown, the distance between any two adjacent silencers 11 is the same.

[0036] To further explain, the equidistant distribution of the silencing holes 11 ensures that the sound waves are evenly scattered within the annular cavity 10, avoiding local sound energy concentration caused by uneven hole spacing, making the sound absorption performance of the entire silencing structure more stable and balanced, and improving the broadband noise reduction effect.

[0037] The working principle of the negative pressure machine silencer made of composite sound-absorbing material provided by this utility model is as follows:

[0038] 1. Start the negative pressure fan: Turn on the negative pressure fan body 1 through the control system or power switch. The negative pressure fan body 1 generates negative pressure and draws outside air into the negative pressure fan body 1 through the silencer duct 2.

[0039] 2. Airflow enters the primary noise reduction mechanism: Air enters the air inlet channel 3 through the silencer duct 2 and first reaches the air inlet 5 at the end of the air inlet duct 4. The middle air inlet 5 and other air inlets 5 distributed in the ring array together guide the airflow to be evenly dispersed, reducing eddy noise.

[0040] 3. Multi-stage noise reduction: After the airflow enters the air inlet duct 4, some sound waves enter the annular cavity 10 of the inner ring silencer 8 and the outer ring silencer 9 through the silencer hole 11. The glass wool material silencer ring 12 in the annular cavity 10 absorbs the mid-to-high frequency noise and converts the sound energy into heat energy. The sound waves are reflected and diffracted multiple times in the annular cavity 10, and interact with the airflow repeatedly through the silencer hole 11, further attenuating the noise energy.

[0041] 4. Airflow discharge and initial elimination mechanism: After being processed by the inner ring silencer 8 and the outer ring silencer 9, the airflow is discharged from the initial elimination mechanism through the air outlet 14 on the sealing cover 13 and enters the subsequent channel of the air inlet channel 3.

[0042] 5. Composite noise reduction effect: As the airflow continues to move forward in the air inlet channel 3, the perforated metal cylinder 15 absorbs noise in a specific frequency band through the principle of resonance. The sound insulation felt 16 filled between the sound-absorbing pipe 2 and the perforated metal cylinder 15 blocks the transmission of noise, thus enhancing the overall noise reduction effect.

[0043] 6. Maintenance Operation: If the primary silencing mechanism needs to be replaced or cleaned, turn off the power supply of the negative pressure fan body 1, remove the bolts connecting the air inlet duct 4 and the sealing cover 13, take out the inner ring silencer 8 and the outer ring silencer 9 for maintenance, and regularly check whether the glass wool silencer ring 12 has accumulated dust or is damaged, and clean or replace it if necessary.

[0044] 7. Shut down the equipment: After production is completed, disconnect the power supply to the negative pressure fan body 1 and stop the equipment from running.

[0045] The above are merely specific embodiments of this utility model, but the technical features of this utility model are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on this utility model to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of this utility model.

Claims

1. A negative pressure machine silencer made of composite sound-absorbing material, characterized in that, It includes a negative pressure fan body (1) and a silencer pipe (2) fixedly installed on the air inlet end of the negative pressure fan body (1). An air inlet channel (3) is provided on the inner side wall of the silencer pipe (2), and a primary silencer mechanism is provided on the inner side wall of the air inlet channel (3) near the pipe opening. The initial silencing mechanism includes an air inlet duct (4) fixedly installed on the inner wall of the air inlet channel (3). Multiple air inlets (5) are provided on the outer wall of the air inlet duct (4). An inner ring groove (6) and an outer ring groove (7) are provided on the inner wall of the air inlet duct (4). An inner ring silencer (8) is slidably connected to the inner wall of the inner ring groove (6), and an outer ring silencer (9) is slidably connected to the inner wall of the outer ring groove (7). The inner ring silencer (8) and the outer ring silencer (9)... The inner ring silencer (8) and the outer ring silencer (9) are provided with multiple silencer holes (11) on their outer and inner walls. The ring cavity (10) and the silencer holes (11) are connected. A silencer ring cylinder (12) is fixedly installed on the inner wall of the ring cavity (10). A sealing cover (13) is fixedly installed at the end of the air inlet cylinder (4). Multiple air outlets (14) are provided on the outer wall of the sealing cover (13).

2. The negative pressure machine silencer made of composite sound-absorbing material according to claim 1, characterized in that, The air inlet duct (4) and the sealing cover (13) are fixed together by multiple bolts.

3. The negative pressure machine silencer made of composite sound-absorbing material according to claim 1, characterized in that, The air inlet (5) and the air inlet tube (4) located in the middle are arranged coaxially, and a plurality of air inlets (5) are arranged in a ring array on the end of the air inlet tube (4).

4. A negative pressure machine silencer made of composite sound-absorbing material according to claim 1, characterized in that, The air inlet (4), inner ring groove (6) and outer ring groove (7) are arranged coaxially, and the air inlet (5) and air outlet (14) on the same side are arranged coaxially.

5. A negative pressure machine silencer made of composite sound-absorbing material according to claim 1, characterized in that, The material of the sound-absorbing ring cylinder (12) is glass wool.

6. A negative pressure machine silencer made of composite sound-absorbing material according to claim 1, characterized in that, A perforated metal tube (15) is fixedly installed on the inner wall of the air inlet channel (3), and the air inlet tube (4) is fixedly installed on the inner wall of the perforated metal tube (15). Sound insulation felt (16) is filled between the inner wall of the silencing pipe (2) and the outer wall of the perforated metal tube (15).

7. A negative pressure machine silencer made of composite sound-absorbing material according to claim 1, characterized in that, The distance between any two adjacent silencers (11) is the same.

Images