Silencer for a vacuum pump

Abstract

This utility model discloses a silencing device for a vacuum pump, relating to the field of noise reduction equipment technology. It includes a first silencing unit and a second silencing unit connected to each other. Both the first and second silencing units have sound-absorbing layers, and each layer has a perforated plate on its outer side. The first silencing unit has a first air inlet and a first air outlet coaxially arranged, with the perforated plate connecting the two. The perforated plate contains an array of several silencing tubes extending axially along the first silencing unit. The second silencing unit has a second air inlet and a second air outlet perpendicularly arranged, with the perforated plate connecting them. The perforated plate contains at least one silencing plate. The cooperation of the first and second silencing units solves the problem of existing silencing devices having a simple structure and being unable to adapt to complex working conditions.

Description

Technical Field

[0001] This utility model relates to the field of noise reduction equipment technology, specifically a silencing device for a vacuum pump. Background Technology

[0002] A vacuum pump is a device or equipment that uses mechanical, physical, chemical or physicochemical methods to evacuate a container to obtain a vacuum. When it is running, it generates a lot of noise at the exhaust port, such as 98-135 dB(A) for Roots pumps and 80-100 dB(A) for water ring pumps. Therefore, it is often necessary to use noise reduction equipment to reduce noise.

[0003] A vacuum pump silencing device, disclosed in CN215058005U, reduces the noise of the vacuum pump by installing a silencing plate at the connection between the silencing device and the vacuum pump exhaust port. Simultaneously, a silencing baffle is installed on the inner wall of the silencing device for primary silencing, a silencing pipe is installed inside the silencing pipeline for secondary silencing, and polyester fiber silencing cotton is filled between the silencing baffle and the silencing pipe for tertiary silencing, significantly reducing the noise of the vacuum pump.

[0004] However, the aforementioned technical solutions suffer from a lack of diversity in their silencing structures. In practical applications, the frequency and intensity of noise generated by vacuum pumps vary significantly under different operating conditions, making it difficult for a single-structure silencing device to effectively attenuate noise at multiple frequencies. For example, when high-frequency and low-frequency noise coexist, the aforementioned devices may only have a good silencing effect on noise in specific frequency bands, while their ability to reduce noise in other frequency bands is insufficient, making them unsuitable for complex operating environments. Therefore, there is an urgent need to design a silencing device for vacuum pumps to adapt to complex operating conditions. Summary of the Invention

[0005] In view of this, the purpose of this application is to overcome the shortcomings of the prior art and to propose a silencing device for a vacuum pump.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: a silencing device for a vacuum pump, comprising a first silencing unit and a second silencing unit that are interconnected, wherein a sound-absorbing layer is provided in both the first and second silencing units, and a silencing perforated plate is provided on the outer side of each sound-absorbing layer; the first silencing unit has a first air inlet and a first air outlet arranged coaxially, and the silencing perforated plate of the first silencing unit connects the first air inlet and the first air outlet, wherein a plurality of silencing tube arrays extending axially along the first silencing unit are provided in the silencing perforated plate of the first silencing unit; the second silencing unit has a second air inlet and a second air outlet arranged perpendicularly to each other, and the silencing perforated plate of the second silencing unit connects the second air inlet and the second air outlet, wherein at least one silencing plate is provided in the silencing perforated plate of the second silencing unit.

[0007] Preferably, the first silencing unit and the second silencing unit are coaxially connected to form a gas passage, the first air inlet is connected to the vacuum pump outlet, and the first air outlet is connected to the second air inlet.

[0008] Preferably, the first silencing unit and the second silencing unit are vertically connected to form a gas passage, the second air inlet is connected to the vacuum pump outlet, and the second air outlet is connected to the first air inlet.

[0009] Preferably, the silencing perforated plate of the first silencing unit has a cylindrical structure, and the silencing tube array includes multiple silencing tubes. The multiple silencing tubes are distributed in a ring shape inside the silencing perforated plate of the first silencing unit and are fixed to the inner wall of the silencing perforated plate of the first silencing unit by a support frame.

[0010] Preferably, each of the multiple silencers has several perforations I.

[0011] Preferably, the silencing plate of the second silencing unit is a cuboid structure, and the silencing plate includes a resonant cavity and two triangular prism fixing brackets. The two triangular prism fixing brackets are respectively fixed on two opposite inner walls inside the silencing plate of the second silencing unit, and the resonant cavity is fixed between the two triangular prism fixing brackets.

[0012] Preferably, the resonant cavity has several perforations II.

[0013] Preferably, the sound-absorbing layer is made of one of glass wool, rock wool, ceramic fiber wool, polyester fiber wool, or polyurethane foam.

[0014] The beneficial effects achieved by this utility model due to the adoption of the above technical solution are as follows: The vacuum pump silencing device forms a multi-stage silencing structure by setting up a first silencing unit and a second silencing unit that are interconnected, with sound-absorbing layers and silencing perforated plates in both units. The silencing tube array of the first silencing unit can perform preliminary silencing treatment on the incoming gas, and the perforations I on the silencing tubes can further disperse and attenuate sound wave energy. The silencing plates of the second silencing unit, with their resonant cavity and triangular prism fixing frame structure, can perform further silencing of the gas, and the perforations II on the resonant cavity can also enhance the silencing effect. This multi-stage silencing structure can effectively attenuate noise of different frequencies and intensities, solving the problem of existing silencing devices having a single structure and being unable to adapt to complex working conditions. It can be widely used in various vacuum pump noise reduction scenarios, effectively reducing the large noise generated at the exhaust port during vacuum pump operation and improving the working environment. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of a silencing device for a vacuum pump according to the present invention; Figure 2 This is a schematic diagram of another installation configuration of the silencing device for a vacuum pump according to this utility model; Figure 3 for Figure 1 Schematic diagram of the structure of section AA in the middle; Figure 4 for Figure 1 A schematic diagram of the structure of the BB cross section.

[0016] The attached diagram lists the components represented by each number as follows: 1. First silencing unit; 11. First air inlet; 12. First air outlet; 13. Silencing tube array; 131. Silencing tube; 132. Support frame; 2. Second silencing unit; 21. Second air inlet; 22. Second air outlet; 23. Silencing plate; 231. Resonance cavity; 232. Triangular prism fixing frame; 3. Sound-absorbing layer; 4a / 4b. Silencing perforated plate. Detailed Implementation

[0017] 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.

[0018] The present invention will be described in detail with the following embodiments: Example

[0019] refer to Figure 1-4 A silencer for a vacuum pump, such as Figure 1 As shown, it includes a first silencing unit 1 and a second silencing unit 2 that are connected to each other. Both the first silencing unit 1 and the second silencing unit 2 are provided with a sound-absorbing layer 3, and the outer side of the sound-absorbing layer 3 is provided with a sound-absorbing perforated plate 4a and 4b. The sound-absorbing layer 3 can be made of glass wool, rock wool, ceramic fiber wool, polyester fiber wool or polyurethane foam (porous type), preferably polyester fiber wool. The shells of the first sound-absorbing unit 1 and the second sound-absorbing unit 2 are made of stainless steel. The sound-absorbing perforated plates 4a and 4b are fixed to the shells by welding or bolting. When the sound-absorbing layer 3 is laid, it completely covers the inner walls of the shells of the first sound-absorbing unit 1 and the second sound-absorbing unit 2, so as to achieve the initial sound absorption of noise.

[0020] like Figure 1As shown, the first silencing unit 1 has a first air inlet 11 and a first air outlet 12 arranged coaxially. The silencing plate 4a of the first silencing unit 1 connects the first air inlet 11 and the first air outlet 12. A plurality of silencing tube arrays 13 extending along the axial direction of the first silencing unit 1 are arranged in the silencing plate 4a of the first silencing unit 1. The first air inlet 11 and the first air outlet 12 are arranged coaxially, so that when the gas flows in the first silencer unit 1, the path is relatively direct, reducing the resistance to gas flow and preventing the generation of new noise.

[0021] At the same time, such as Figure 1 and 3 As shown, the silencing plate 4a of the first silencing unit 1 is a cylindrical structure. The silencing tube array 13 includes multiple silencing tubes 131. The multiple silencing tubes 131 are distributed in a ring shape inside the silencing plate 4a of the first silencing unit 1 and are fixed on the inner wall of the silencing plate 4a of the first silencing unit 1 by a support frame 132. Several through holes I are opened on each of the multiple silencing tubes 131. The cylindrical structure of the silencing plate 4a, combined with the annular distribution of the silencing tube array 13, effectively increases the contact area between the gas and the silencing structure, allowing noise of different frequencies to be attenuated to a certain extent when passing through the silencing tubes 131. Furthermore, each of the multiple silencing tubes 131 has several perforations I, which further disperse and disperse the airflow, causing noise to undergo multiple reflections and interferences at the perforations I, thereby enhancing the silencing effect, especially for mid-to-high frequency noise.

[0022] In the above structure, the silencing tube array 13 divides the large airflow channel formed by the silencing perforated plate 4a into many small parallel airflow channels. When the sound wave propagates in the pipe, the pipe cross-section suddenly changes, and some of the sound wave will be reflected back due to impedance mismatch, unable to continue propagating forward. At the same time, this structure increases the contact area between the sound wave and the pipe wall, thereby increasing the chance of reflection and interference, and consuming sound energy. This is especially effective for mid-to-high frequency noise because the wavelength of mid-to-high frequency sound waves is shorter and more easily affected by these small-scale structures. When the sound wave propagates to the perforation I, it will excite the air column at the hole I to vibrate like a piston. When the frequency of the external sound wave is the same as or close to the natural frequency of the resonant cavity, resonance will occur. During resonance, the air column rubs and vibrates violently at the hole, converting the sound energy (mechanical energy) into heat energy to the maximum extent, thereby consuming it.

[0023] like Figure 1 As shown, the second silencing unit 2 has a second air inlet 21 and a second air outlet 22 arranged perpendicularly to each other. The silencing plate 4b of the second silencing unit 2 is connected to the second air inlet 21 and the second air outlet 22. At least one silencing plate 23 is provided in the silencing plate 4b of the second silencing unit 2.

[0024] The perpendicular arrangement of the second air inlet 21 and the second air outlet 22 changes the direction of gas flow, causing the gas to form a more complex flow path within the second silencing unit 2. This complex flow path allows noise to collide with the silencing structure multiple times in different directions, further improving the silencing effect.

[0025] At the same time, such as Figure 1 and 4 As shown, the silencing plate 4b of the second silencing unit 2 is a cuboid structure. The silencing plate 23 includes a resonant cavity 231 and two triangular prism fixing brackets 232. The two triangular prism fixing brackets 232 are respectively fixed on two opposite inner walls of the silencing plate 4b of the second silencing unit 2. The resonant cavity 231 is fixed between the two triangular prism fixing brackets 232. Several perforations II are opened on the resonant cavity 231.

[0026] Specifically, the height of the resonant cavity 231 gradually increases from the second air inlet 21 toward the second air outlet 22. The upper part of the resonant cavity 231 is fixed on the inner wall of the silencing plate 4b below the second air inlet 21. The lower part of the resonant cavity 231 and the lower triangular prism fixing bracket 232 form a chamfer at the tail end, and the upper triangular prism fixing bracket 232 is inclined.

[0027] The combination of the cuboid-shaped silencing plate 4b and the silencing sheet 23 provides more reflective surface and silencing space for noise. Several perforations II are opened on the resonant cavity 231. When the gas carrying noise passes through the perforations II, eddies are formed in the resonant cavity 231, so that the noise energy is continuously consumed in the eddies, thereby effectively reducing the noise intensity, especially with good absorption and attenuation effect on low-frequency noise.

[0028] In the above structure, the core structure of the silencing plate 23 is the resonant cavity 231. Its large internal cavity contrasts sharply with the small cavity of the silencing tube. The low-frequency noise has an extremely long wavelength, and a sufficiently large cavity volume is required to excite effective resonance. When the low-frequency sound wave is incident, the sound wave pushes the air into the resonant cavity 231, forming a large amplitude vibration in the cavity. A large amount of low-frequency energy is converted into heat energy through air molecule friction and cavity wall vibration, thus achieving attenuation.

[0029] The combination of the triangular prism fixing frame 232 of the silencing plate 23 and the resonant cavity 231 creates an acoustic impedance abrupt change interface within the silencing unit. When low-frequency sound waves propagate, they encounter media with different acoustic impedances (air → triangular prism metal frame → air in the resonant cavity), resulting in a large number of reflections. Because the energy of low-frequency sound waves is concentrated in the propagation direction, the impedance abrupt change causes most of the low-frequency sound waves to be reflected back to the sound source side and unable to continue propagating.

[0030] Meanwhile, the cuboid structure of the sound-absorbing plate 23, combined with the cuboid sound-absorbing perforated plate 4b of the second sound-absorbing unit, ensures that the low-frequency sound waves need to change their propagation direction when turning due to the perpendicularity between the second air inlet 21 and the second air outlet 22. However, since the wavelength is too long, energy loss will occur due to the sudden change in the path during the turning process. This resistance sound insulation mechanism has a significant effect on blocking low-frequency noise.

[0031] A perforation II is made in the resonant cavity 231. When airflow carrying low-frequency noise enters the cavity through perforation II, it will form a vortex inside the cavity. The kinetic energy of the low-frequency airflow is coupled with the energy of the low-frequency sound wave. During the vortex motion, the viscous force between air molecules will convert a large amount of kinetic energy into heat energy. At the same time, the vortex will break the directional propagation characteristics of the low-frequency sound wave, causing the sound wave energy to be dispersed in all directions of the cavity, and further dissipated through absorption by the cavity wall.

[0032] In practical applications, the first silencing unit 1 and the second silencing unit 2 can be connected in two ways. One way is that the first silencing unit 1 and the second silencing unit 2 are coaxially connected to form a gas passage channel, such as... Figure 1 As shown, at this time, the first air inlet 11 is connected to the vacuum pump outlet, and the first air outlet 12 is connected to the second air inlet 21. In this connection mode, the gas enters the first air inlet 11 from the vacuum pump outlet, and after the initial silencing by the first silencing unit 1, it enters the second air inlet 21 from the first air outlet 12, and after further silencing by the second silencing unit 2, it is finally discharged from the second air outlet 22.

[0033] Another type is where the first silencing unit 1 and the second silencing unit 2 are vertically connected to form a gas passage channel, such as... Figure 2 As shown, the second air inlet 21 is connected to the vacuum pump outlet, and the second air outlet 22 is connected to the first air inlet 11. In this configuration, gas enters the second air inlet 21 from the vacuum pump outlet, is first silenced by the second silencing unit 2, then enters the first air inlet 11 from the second air outlet 22, and is finally silenced by the first silencing unit 1 before being discharged from the first air outlet 12. These two connection methods can be selected according to different operating conditions to adapt to various complex working environments, solving the problem that existing silencing devices have a simple structure and cannot adapt to complex working conditions.

[0034] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0035] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A silencer for a vacuum pump, characterized in that, It includes a first silencing unit (1) and a second silencing unit (2) that are connected to each other. Both the first silencing unit (1) and the second silencing unit (2) are provided with a sound-absorbing layer (3). The outer side of the sound-absorbing layer (3) is provided with a sound-absorbing perforated plate (4a, 4b). The first silencing unit (1) has a first air inlet (11) and a first air outlet (12) arranged coaxially. The silencing perforated plate (4a) of the first silencing unit (1) is connected to the first air inlet (11) and the first air outlet (12). A plurality of silencing tube arrays (13) extending along the axial direction of the first silencing unit (1) are arranged in the silencing perforated plate (4a) of the first silencing unit (1). The second silencing unit (2) has a second air inlet (21) and a second air outlet (22) arranged perpendicularly to each other. The silencing plate (4b) of the second silencing unit (2) is connected to the second air inlet (21) and the second air outlet (22). At least one silencing plate (23) is provided in the silencing plate (4b) of the second silencing unit (2).

2. The silencing device for a vacuum pump according to claim 1, characterized in that, The first silencing unit (1) and the second silencing unit (2) are coaxially connected to form a gas passage. The first air inlet (11) is connected to the vacuum pump outlet, and the first air outlet (12) is connected to the second air inlet (21).

3. The sound attenuation device for a vacuum pump according to claim 1, characterized by The first silencing unit (1) and the second silencing unit (2) are vertically connected to form a gas passage. The second air inlet (21) is connected to the vacuum pump outlet, and the second air outlet (22) is connected to the first air inlet (11).

4. The silencing device for a vacuum pump according to claim 2 or 3, characterized in that, The silencing perforated plate (4a) of the first silencing unit (1) is a cylindrical structure. The silencing tube array (13) includes multiple silencing tubes (131). The multiple silencing tubes (131) are distributed in a ring shape inside the silencing perforated plate (4a) of the first silencing unit (1) and are fixed on the inner wall of the silencing perforated plate (4a) of the first silencing unit (1) by a support frame (132).

5. The sound attenuation device for a vacuum pump according to claim 4, characterized in that, Several perforations (I) are provided on each of the multiple silencer tubes (131).

6. The sound attenuation device for a vacuum pump according to claim 2 or 3, characterized in that, The second silencing unit (2) has a cuboid structure for its silencing perforated plate (4b). The silencing plate (23) includes a resonant cavity (231) and two triangular prism fixing brackets (232). The two triangular prism fixing brackets (232) are respectively fixed on two opposite inner walls of the silencing perforated plate (4b) of the second silencing unit (2). The resonant cavity (231) is fixed between the two triangular prism fixing brackets (232).

7. The sound attenuation device for a vacuum pump according to claim 6, characterized in that The resonant cavity (231) has several perforations II.

8. The silencing device for a vacuum pump according to claim 1, characterized in that, The sound-absorbing layer (3) is made of one of glass wool, rock wool, ceramic fiber wool, polyester fiber wool or polyurethane foam.

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