阅读说明：本技术 一种高速高压离心鼓风机降噪结构及其降噪方法 (Noise reduction structure and noise reduction method of high-speed high-pressure centrifugal blower ) 是由 桂云峰 张勇 杨崎峰 杜海英 李毅 于 2021-08-25 设计创作，主要内容包括：本发明公开了一种高速高压离心鼓风机降噪结构及其降噪方法,包括上箱体、下箱体和连接风筒,所述上箱体的底端通过连接风筒竖直连接在下箱体的顶端,在上箱体的前侧设置有出风口,在下箱体的后侧设置有进风口,在下箱体内具有谐振腔体、出风消音腔体、第一过滤板和多层消音通道板,由进风口至出风消音腔体之间的谐振腔体内依次设置所述第一过滤板和消音通道板,在所述上箱体内的左右两侧壁及顶部安装有1/4波长管,在所述上箱体的前侧内壁上且沿出风口外围设置有导流板。本发明通过将高速风流由下箱体向上箱体流动的路径中被逐渐减弱,高速空气在高速流动过程中不仅增加消声管道长度,同时在谐振腔体内严格控制了空气的流速,能够达到良好的抑制消音降噪效果。(The invention discloses a noise reduction structure of a high-speed high-pressure centrifugal blower and a noise reduction method thereof, and the noise reduction structure comprises an upper box body, a lower box body and a connecting air duct, wherein the bottom end of the upper box body is vertically connected to the top end of the lower box body through the connecting air duct, an air outlet is arranged at the front side of the upper box body, an air inlet is arranged at the rear side of the lower box body, a resonant cavity, an air outlet noise reduction cavity, a first filter plate and a plurality of layers of noise reduction channel plates are arranged in the lower box body, the first filter plate and the noise reduction channel plates are sequentially arranged in the resonant cavity between the air inlet and the air outlet noise reduction cavity, 1/4 wave-length tubes are arranged on the left side wall and the right side wall and the top in the upper box body, and a guide plate is arranged on the inner wall of the front side of the upper box body and along the periphery of the air outlet. According to the invention, high-speed wind flow is gradually weakened in a path of flowing from the lower box body to the upper box body, so that the length of the silencing pipeline is increased in the high-speed air flowing process, and meanwhile, the flow speed of the air is strictly controlled in the resonant cavity, and good silencing and noise reduction effects can be achieved.)

1. The utility model provides a structure of making an uproar falls in high-speed high-pressure centrifugal blower which characterized in that: the noise reduction structure comprises a noise reduction box body, the noise reduction box body comprises an upper box body, a lower box body and a connecting air duct, the bottom end of the upper box body is vertically connected with the top end of the lower box body through the connecting air duct, an air outlet is arranged at the front side of the upper box body, an air inlet is arranged at the rear side of the lower box body, a resonance cavity, an air outlet silencing cavity, a first filter plate and a plurality of layers of silencing channel plates are arranged in the lower box body, the lower box body is divided into a resonant cavity and an air outlet silencing cavity, the first filter plate and the silencing channel plate are sequentially arranged in the resonant cavity from the air inlet to the air outlet silencing cavity, 1/4 wave tubes are arranged on the left and right side walls and the top in the upper box body, a guide plate is arranged on the inner wall of the front side of the upper box body and along the periphery of the air outlet, an air outlet connecting pipe is arranged on the outer wall of the front side of the upper box body and along the air outlet direction of the air outlet.

2. The noise reduction structure of a high-speed high-pressure centrifugal blower according to claim 1, wherein: one side of keeping away from first filter at the amortization passageway board is provided with the second filter, still is provided with the grid net in wind gap department, the second filter will lower box internal partitioning is resonance cavity and air-out amortization cavity, the second filter is located connect the vertical direction rear side of dryer lower extreme, first filter and second filter setting are in the resonance cavity of box down, wherein, the upper end of first filter and the upper end of second filter are connected respectively on the top inner wall of box down, the lower extreme of first filter and the lower extreme of second filter are connected respectively on the bottom inner wall of box down.

3. A high speed high pressure centrifugal blower noise reduction structure according to claim 1 or 2, characterized in that: the number of the connecting air cylinders is more than 1 or 2, a plurality of layers of silencing channel plates are distributed in the resonant cavity of the lower box body at intervals in the vertical direction from the top end to the bottom end, and a silencing ventilation channel is formed between every two adjacent layers of silencing channel plates.

4. The noise reduction structure of a high-speed high-pressure centrifugal blower according to claim 3, wherein: each layer of the silencing channel plate is an inverted V-shaped silencing channel plate or a herringbone silencing channel plate, and a V-shaped or herringbone silencing ventilation channel is formed between each layer of the inverted V-shaped silencing channel plate or the herringbone silencing channel plate.

5. The noise reduction structure of a high-speed high-pressure centrifugal blower according to claim 3, wherein: the inner wall of the front side of the lower box body is provided with a sound absorption element.

6. The noise reduction structure of a high-speed high-pressure centrifugal blower according to claim 1, wherein: the upper box body comprises an upper box outer shell and an upper box inner shell arranged along the peripheral inner wall of the upper box outer shell in a clearance manner, a buffer silencing cavity body which is communicated with each other is arranged between the inner bottom end of the outer casing body of the upper box and the outer bottom end of the inner casing body of the upper box in a separating way, the bottom of the buffering silencing cavity is communicated with the top of the air outlet silencing cavity of the lower box body through a connecting air duct, the bottom of the inner shell of the upper box body is communicated with the buffering silencing cavity through an air outlet channel opening, a plurality of 1/4 wave tubes are arranged on the left side wall, the right side wall and the top of the inner shell of the upper box at intervals, the guide plate is arranged above the buffering and silencing cavity and along the periphery of the air outlet, the front side of the guide plate penetrates through the front side wall of the upper inner box shell and then is connected to the front side inner wall of the upper outer box shell, and the rear side of the guide plate is in close contact with the rear side wall of the upper inner box shell.

7. The noise reduction structure of a high-speed high-pressure centrifugal blower according to claim 6, wherein: the 1/4 wave tube has an open end and a closed end, the closed end of the 1/4 wave tube is vertically contacted with the inner side wall of the upper box outer shell, and the open end of the 1/4 wave tube vertically extends to the center direction along the left and right side walls and the top of the upper box inner shell.

8. The noise reduction structure of a high-speed high-pressure centrifugal blower according to claim 6, wherein: the guide plate is an upwards-opened U-shaped guide plate, a V-shaped guide plate or an arc-shaped guide plate, the top of the buffering and silencing cavity is hollowed out, the lower end of the guide plate is positioned above the top of the buffering and silencing cavity, and the upper end opening of the guide plate upwards extends along the periphery of the air outlet and is close to the top end of the inner shell of the upper box.

9. A high speed high pressure centrifugal blower noise reduction structure according to claim 6 or 8, wherein: the top of the impact silencing cavity is sealed, air outlet channel openings are formed in two ends of the top of the buffering silencing cavity, and the lower end of the guide plate is fixedly connected with the outer wall of the top of the impact silencing cavity.

10. A noise reduction method of a high-speed high-pressure centrifugal blower is characterized in that: a high speed high pressure centrifugal blower noise reduction structure using any one of claims 1 to 9, comprising the steps of: connecting the front side of the upper box body with a high-speed high-pressure centrifugal blower and a connecting air outlet, and enabling high-speed air flow to sequentially enter an air outlet silencing cavity and a resonance cavity along an air inlet, wherein the flow velocity of the high-speed air flow entering the air inlet is not more than 7 m/s; the high-speed air flow enters the air outlet silencing cavity and is filtered by the grille net and the first filter plate, and the filtered high-speed air flow is subjected to preliminary noise reduction in a V-shaped plate or a herringbone silencing ventilation duct formed by a plurality of layers of silencing channel plates; the high-speed air flow that preliminarily made an uproar upwards sends into buffering amortization cavity through resonance cavity, a plurality of connection dryer and carries out the amortization once more and fall and make an uproar, and high-speed air current continues the lateral wall of flow guide plate upwards to flow, is the 1/4 wavelength pipe contact that interval distribution installed with the left and right sides wall and the top of last incasement shell respectively and carries out the amortization and fall and make an uproar, and high-speed air current flows downwards and discharges from the air outlet from the inside wall of flow guide plate at last, gets into high-speed high-pressure centrifugal blower.

Technical Field

The invention belongs to the technical field of noise reduction of high-speed and high-pressure blowers, particularly relates to the technical field of noise elimination and reduction of blowers, and particularly relates to a noise reduction structure of a high-speed and high-pressure centrifugal blower and a noise reduction method thereof.

Background

The high-frequency pneumatic noise generated by the high-speed high-pressure blower during high-speed operation is large, the noise needs to be reduced to a reasonable range, however, the requirement of a noise reduction and noise elimination material adopted for noise reduction is high, and the device for controlling the noise reduction and noise elimination has a large volume, occupies a large space and has a large influence on the performance of the whole blower. The existing device for treating the noise of the equipment is provided with devices for damping and reducing noise, absorbing and reducing noise, insulating and reducing noise, comprehensively reducing noise and the like, and the structural type of the device can be divided into three types of resistive noise reduction, resistant noise reduction and impedance combined noise reduction. The vibration and noise reduction technology is to research vibration isolation and noise reduction from the noise control angle, only to research how to reduce air noise and mechanical noise, and to change the nearly rigid connection between a vibration source (namely a sound source) and a foundation or other objects into elastic connection to prevent or weaken the transmission of vibration energy; the sound absorption and noise reduction technology is a traditional common and effective device for controlling a noise transmission path by using a sound absorption technology, when sound waves meet various solid obstacles in the transmission process, one part of the sound waves are reflected, the other part of the sound waves enter the inside of the solid obstacles to be absorbed, and a small part of the sound waves can be transmitted to the other side of the solid obstacles; the sound insulation and noise reduction technology is a commonly used technical measure in noise control engineering, various plates and components of a wall body are used as shielding objects or maintenance structures, noise is controlled within a certain range, and the noise is prevented from being transmitted in the air and cannot pass through the air smoothly, so that the purpose of reducing the noise is achieved. The noise reduction device has a complex structure, the adopted materials are mainly soundproof cotton (rubber plates, foamed rubber plates, damping plates and the like), silencing cotton (polyester fibers, centrifugal glass cotton, rock wool, mineral wool, plant fibers and the like) and porous soundproof materials (galvanized mesh plates, stainless steel mesh plates and the like), and the noise reduction coefficients of the materials are low (not more than 0.8). Therefore, the existing noise reduction device is difficult to solve and eliminate the problem of large high-frequency pneumatic noise, and in view of this, noise reduction of the high-speed high-pressure blower is a key technical problem to be solved urgently.

Disclosure of Invention

The invention aims to provide a noise reduction structure of a high-speed high-pressure centrifugal blower and a noise reduction method thereof. In order to achieve the purpose, the invention adopts the following technical scheme:

according to one aspect of the invention, a noise reduction structure of a high-speed high-pressure centrifugal blower is provided, the noise reduction structure comprises a noise reduction box body, the noise reduction box body comprises an upper box body, a lower box body and a connecting air duct, the bottom end of the upper box body is vertically connected to the top end of the lower box body through the connecting air duct, an air outlet is arranged on the front side of the upper box body, an air inlet is arranged on the rear side of the lower box body, a resonant cavity, an air outlet noise reduction cavity, a first filter plate and a plurality of layers of noise reduction channel plates are arranged in the lower box body, the lower box body is internally divided into the resonant cavity and the air outlet noise reduction cavity, the first filter plate and the noise reduction channel plates are sequentially arranged in the resonant cavity between the air inlet and the air outlet noise reduction cavity, 1/4 wave long pipes are arranged on the left side wall, the right side wall and the top in the upper box body, a guide plate is arranged on the inner wall of the front side of the upper box body and along the periphery of the air outlet, an air outlet connecting pipe is arranged on the outer wall of the front side of the upper box body and along the air outlet direction of the air outlet.

The scheme is further preferred, one side of keeping away from first filter at the amortization passageway board is provided with the second filter, still is provided with the grid net in wind inlet department, the second filter will for resonant cavity and air-out amortization cavity down the box internal partitioning, the second filter is located connect the vertical direction rear side of dryer lower extreme, first filter and second filter setting are in the resonant cavity of box down, wherein, the upper end of first filter and the upper end of second filter are connected respectively on the top inner wall of box down, the lower extreme of first filter and the lower extreme of second filter are connected respectively on the bottom inner wall of box down.

The above scheme is further preferred, the number of the connecting air ducts is more than 1 or 2, a plurality of layers of the silencing channel plates are distributed in the resonant cavity of the lower box body at intervals in the vertical direction from the top end to the bottom end, and a silencing ventilation channel is formed between every two adjacent layers of the silencing channel plates.

According to the scheme, the scheme is further preferable, each layer of the silencing channel plate is an inverted V-shaped silencing channel plate or a herringbone silencing channel plate, and a V-shaped or herringbone silencing ventilation channel is formed between each layer of the inverted V-shaped silencing channel plate or the herringbone silencing channel plate.

In the above aspect, it is further preferable that a sound absorbing member is provided on the front inner wall of the lower case.

In a further preferred mode of the above scheme, the upper box body comprises an upper box outer shell and an upper box inner shell arranged along the peripheral inner wall of the upper box outer shell in a clearance manner, a buffer silencing cavity body which is communicated with each other is arranged between the inner bottom end of the outer casing body of the upper box and the outer bottom end of the inner casing body of the upper box in a separating way, the bottom of the buffering silencing cavity is communicated with the top of the air outlet silencing cavity of the lower box body through a connecting air duct, the bottom of the inner shell of the upper box body is communicated with the buffering silencing cavity through an air outlet channel opening, a plurality of 1/4 wave tubes are arranged on the left side wall, the right side wall and the top of the inner shell of the upper box at intervals, the guide plate is arranged above the buffering and silencing cavity and along the periphery of the air outlet, the front side of the guide plate penetrates through the front side wall of the upper inner box shell and then is connected to the front side inner wall of the upper outer box shell, and the rear side of the guide plate is in close contact with the rear side wall of the upper inner box shell.

Preferably, one end of the 1/4 wave tube is open, and the other end is closed, the closed end of the 1/4 wave tube is vertically contacted with the inner side wall of the upper box outer shell, and the open end of the 1/4 wave tube vertically extends to the center direction along the left and right side walls and the top of the upper box inner shell.

The above scheme is further preferred, the guide plate is the U-shaped guide plate, V-arrangement guide plate or the arc guide plate of upwards open-ended, the top fretwork of buffering amortization cavity, the lower extreme of guide plate is located the top of buffering amortization cavity, and the upper end opening of this guide plate upwards extends along the air outlet periphery and is close to the inside top of last incasement shell.

The scheme is further preferred, the top of the impact silencing cavity is sealed, air outlet channel openings are formed in two ends of the top of the buffering silencing cavity, and the lower end of the guide plate is fixedly connected with the outer wall of the top of the impact silencing cavity.

According to another aspect of the present invention, there is provided a noise reduction method of a high-speed high-pressure centrifugal blower, comprising the steps of: connecting the front side of the upper box body with a high-speed high-pressure centrifugal blower and a connecting air outlet, and enabling high-speed air flow to sequentially enter an air outlet silencing cavity and a resonance cavity along an air inlet, wherein the flow velocity of the high-speed air flow entering the air inlet is not more than 7 m/s; the high-speed air flow enters the air outlet silencing cavity and is filtered by the grille net and the first filter plate, and the filtered high-speed air flow is subjected to preliminary noise reduction in a V-shaped plate or a herringbone silencing ventilation duct formed by a plurality of layers of silencing channel plates; the high-speed air flow that preliminarily made an uproar upwards sends into buffering amortization cavity through resonance cavity, a plurality of connection dryer and carries out the amortization once more and fall and make an uproar, and high-speed air current continues the lateral wall of flow guide plate upwards to flow, is the 1/4 wavelength pipe contact that interval distribution installed with the left and right sides wall and the top of last incasement shell respectively and carries out the amortization and fall and make an uproar, and high-speed air current flows downwards and discharges from the air outlet from the inside wall of flow guide plate at last, gets into high-speed high-pressure centrifugal blower.

In summary, the invention adopts the above technical scheme, and the invention has the following technical effects:

the noise reduction structure can absorb low-frequency noise entering the lower box body, the upper box body can capture and resist most high-frequency noise, so that the high-frequency noise of the original airflow is reduced by impedance, and high-speed airflow is gradually weakened in a path of flowing from the lower box body to the upper box body, so that the noise reduction of medium-high frequency noise achieves an ideal effect; the path through which the high-speed wind flow (air) flows not only increases the length of the silencing pipeline, but also increases the silencing area, strictly controls the flow speed of the air in the noise reduction structure, and can achieve good silencing and noise reduction effects.

Drawings

FIG. 1 is a schematic front view of a noise reducing structure of a high speed, high pressure centrifugal blower according to the present invention;

FIG. 2 is a schematic rear view of a noise reduction structure of a high-speed high-pressure centrifugal blower according to the present invention;

FIG. 3 is a schematic view of the internal overall structure of a noise reduction structure of a high-speed high-pressure centrifugal blower according to the present invention;

FIG. 4 is a schematic side view of a high speed, high pressure centrifugal blower noise reduction structure of the present invention;

FIG. 5 is a schematic structural view of a lower case of the present invention;

FIG. 6 is a schematic structural view of a first embodiment of the upper case of the present invention;

FIG. 7 is a schematic structural view of a second embodiment of the upper case of the present invention;

in the drawing, an upper box outer shell 100, an upper box inner shell 101, a buffering and silencing cavity 102, a protrusion 102a, an air outlet passage port 103, a noise reduction box body 200, an upper box 1, a lower box 2, a connecting air duct 3, an air outlet 10, an 1/4 wave tube 11, a guide plate 12, an air outlet connecting pipe 13, an air inlet 20, a resonant cavity 21, an air outlet silencing cavity 21a, a first filter plate 22, a silencing passage plate 23, a second filter plate 24, a silencing air duct 25, and a sound absorption element 26.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings by way of examples of preferred embodiments. It should be noted, however, that the numerous details set forth in the description are merely for the purpose of providing the reader with a thorough understanding of one or more aspects of the present invention, which may be practiced without these specific details.

Referring to fig. 1, 2, 3 and 4, the noise reduction structure of a high-speed high-pressure centrifugal blower according to the present invention comprises a noise reduction box body 200, wherein the noise reduction box body 200 comprises an upper box body 1, a lower box body 2 and connecting air ducts 3, the number of the connecting air ducts 3 is 1 or more than 2, the number of the connecting air ducts 3 is preferably 4, the bottom end of the upper box body 1 is vertically connected to the top end of the lower box body 2 through the connecting air ducts 3, the high-speed air of the lower box body 2 flows through the connecting air ducts 3 into the upper box body 1, so that the high-speed air flows in the connecting air ducts 3 to reduce vibration and eliminate noise, an air outlet 10 is arranged on the front side of the upper box body 1, an air inlet 20 is arranged on the rear side of the lower box body 2, the air outlet 10 is connected to the high-speed high-pressure centrifugal blower, the high-frequency air sucked by the high-speed high-pressure centrifugal blower flows through the air inlet 20 and is fed into the lower box body 2 to reduce noise, then the air is sent into the upper box body 1 through the connecting air duct 3 for noise reduction, and high-speed air flows out of the air outlet 10 and enters the high-speed high-pressure centrifugal blower to be sent out; 1/4 wave tubes 11 are arranged on the left and right side walls and the top in the upper box body 1, thereby forming a 1/4 wave tube array for eliminating medium and high frequency noise, a guide plate 12 is arranged on the inner wall of the front side of the upper box body 1 and along the periphery of the air outlet 10, an air outlet connecting pipe 13 is arranged on the outer wall of the front side of the upper box body 1 and along the air outlet direction of the air outlet 10, can be connected with the inlet of the high-speed high-pressure centrifugal blower through the air outlet connecting pipe 13, 1/4 wave tubes are uniformly distributed and applied in the upper box body 1, 1/4 wave tubes generate resisting sound to the noise of corresponding frequency bands, can capture and resist most high-frequency noise, so that the high-frequency noise of the primary air flow is reduced by the resistance, one part of the low-frequency noise is absorbed in the process of returning to and entering the lower box body 2, and the other part of the low-frequency noise enters the air outlet 10 along the guide plate 12 and is sent to the pressure centrifugal blower; in the present invention, as shown in fig. 4 and 5, a resonance chamber 21, an outlet silencing chamber 21a, a first filter plate 22 and a multi-layer silencing passage plate 23 are provided in the lower box 2, the interior of the lower box body 2 is divided into a resonant cavity 21 and an air outlet silencing cavity 21a, the first filter plate 22 and a silencing channel plate 23 are sequentially arranged in the resonant cavity 21 from the air inlet 20 to the air outlet silencing cavity 21a, a second filter plate 24 is provided on the side of the silencing passage plate 23 remote from the first filter plate 22, a grid net (not shown) is further disposed at the air inlet 20, and after the high-frequency and high-speed air flow enters from the air inlet 20, the air is filtered by a grating net and a first filter plate 22, and then is blocked by a multi-layer silencing channel plate 23 to form bending and turning flow, so that the noise generated by high-speed air flow is weakened, and the noise reduction treatment effect is achieved; the second filter plate 24 divides the interior of the lower box body 2 into a resonance cavity 21 and an air outlet silencing cavity 21a, the second filter plate 24 is positioned at the rear side of the lower end of the connecting air duct 3 in the vertical direction, the first filter plate 22 and the second filter plate 24 are arranged in the resonance cavity 21 of the lower box body 2, wherein the upper end of the first filter plate 22 and the upper end of the second filter plate 24 are respectively connected on the inner wall of the top end of the lower box body 2, the lower end of the first filter plate 22 and the lower end of the second filter plate 24 are respectively connected on the inner wall of the bottom end of the lower box body 2, a high-frequency high-speed air flow enters from the air inlet 20 and is subjected to speed reduction in the air outlet silencing cavity 21a through the filter plate filtering and silencing channel plate 23 and is sent into the resonance cavity 21, the volume of the resonance cavity 21 is more than 4 times of the volume of the air outlet silencing cavity 21a, so as to store, buffer and reduce the speed in the high-frequency high-speed air flow resonance cavity 21, the volume of the upper box body 1 is smaller than that of the resonant cavity 21 of the lower box body 2, air flow sent out from the resonant cavity 21 is further subjected to noise reduction in the upper box body, the upper box body 1 and the lower box body 2 are mainly made of carbon steel structures, the material thickness is 2-3 mm according to acoustic vibration requirements, reinforcing ribs are arranged, and control of overall noise caused by vibration of the cavities is prevented.

In the invention, as shown in fig. 4 and 5, a plurality of layers of the silencing channel plates 23 are distributed in the resonance cavity 21 of the lower box body 2 at intervals in the vertical direction from the top end to the bottom end, a silencing ventilation channel 25 is formed between every two adjacent layers of the silencing channel plates 23, each layer of the silencing channel plates 23 is an inverted V-shaped silencing channel plate or a herringbone silencing channel plate, a V-shaped or herringbone silencing ventilation channel 25 is formed between every two layers of the inverted V-shaped silencing channel plates or the herringbone silencing channel plates, air flow is bent and flows in a V-shaped or herringbone manner in the silencing ventilation channel 2 between every two layers of the silencing channel plates 23 at a high speed, friction is generated on the silencing channel plates 23, the flow direction is changed, and the generated noise is weakened in the transmission path, so that the noise reduction and treatment of medium-high-frequency noise achieve the ideal effect. The silencing channel plate 23 is a silicon crystal sand plate, the thickness of the silicon crystal sand plate is 25-45 mm, silencing blind grooves are uniformly distributed on the surface of the silicon crystal sand plate, and the silicon crystal sand plate is suitable for medium-high frequency noise treatment, so that low-frequency noise is absorbed, and the medium-high frequency noise is reduced to achieve an ideal effect; the sound absorption element 26 is arranged on the inner wall of the front side of the lower box body 2, the sound absorption element 26 (sound absorption material) is a sound absorption element such as glass fiber, a silicon crystal plate or suction cotton, so that high-frequency noise is damped in the resonant cavity 21 of the lower box body 2, and the effects of noise reduction and noise reduction are achieved.

In the present invention, as shown in fig. 3 and fig. 6, the upper box 1 includes an upper box outer casing 100 and an upper box inner casing 101 disposed along the peripheral inner wall of the upper box outer casing 100 with a gap, a buffer silencing cavity 102 disposed between the inner bottom of the upper box outer casing 100 and the outer bottom of the upper box inner casing 101 and communicating with each other is partitioned, the bottom of the buffer silencing cavity 102 communicates with the top of the outlet silencing cavity 21a of the lower box 2 through a connecting wind pipe 3, the front side of the buffer silencing cavity 102 and the front side of the lower end of the upper box outer casing 100 are provided with a protrusion 102a protruding toward the front side of the upper box outer casing 100, the protrusion 102a is flush with the front side wall of the lower box 2, the inner width of the buffer silencing cavity 102 is greater than the inner width of the lower end of the upper box inner casing 101, so as to increase the volume thereof and accommodate more air volume, plays a certain role in reducing noise and speed of the high-speed air flow. It is a plurality of to be interval distribution at the left and right sides wall and the top of casing 101 in last case 1/4 wave tube 11, in the top of buffering amortization cavity 102 and along air outlet 10 periphery setting guide plate 12, the front side of this guide plate 12 run through and connect on the front side inner wall of last case shell body 100 behind the preceding lateral wall of casing 101 in last case, the rear side of guide plate 12 with the back lateral wall in close contact with of casing 101 in last case to carry out the shutoff with both sides around guide plate 12 through the front and back inside wall of last case shell body 100, make high-speed air flow along guide plate 12 internal guide flow.

In the present invention, as shown in fig. 3 and 6, one end of the 1/4 wave tube 11 is open, and the other end is closed, the closed end of the 1/4 wave tube 11 vertically contacts the inner sidewall of the upper box outer casing 100, the open end of the 1/4 wave tube 11 vertically extends to the center direction along the left and right sidewalls and the top of the upper box inner casing 101, the length of the open end of the 1/4 wave tube 11 vertically extending to the center direction of the upper box inner casing 101 is not more than 6mm, that is, the length of the open end of the 1/4 wave tube 11 protruding to the direction of the upper box inner casing 101 is not more than 6mm, when the high-speed air flow enters the 1/4 wave tube 11 of the upper box inner casing 101, the 1/4 wave tube 11 generates a sound resisting the noise of the corresponding frequency band, and respectively treats the noise of the frequency bands of 2000Hz, 4000Hz, and 6000Hz, thereby eliminating the sound level of the original noise. The original noise is processed and returned, and then flows into the air inlet 20 along the guide plate 12, and is captured and counteracted in the process of returning to the buffering silencing cavity 102 of the upper box inner shell 101 and the lower box 2, so that the high-frequency noise of the original air flow is reduced by impedance, and the noise generated by the high-speed air flow in the flowing process is further weakened, thereby achieving the noise reduction treatment effect.

In the embodiment of the present invention, as shown in fig. 3 and fig. 6, the flow guiding plate 12 is a U-shaped flow guiding plate, a V-shaped flow guiding plate or an arc-shaped flow guiding plate which is opened upward, the top of the buffering and noise-reducing cavity 102 is hollow, the lower end of the flow guiding plate 12 is located above the top of the buffering and noise-reducing cavity 102, the upper end opening of the flow guiding plate 12 extends upward along the periphery of the air outlet 10 to be close to the top end of the inside of the upper box inner shell 101, the distance between the upper end of the flow guiding plate 12 and the inner wall of the top end of the upper box inner shell 101 is set according to the flow rate of the high-speed air flow, because the front and rear sides of the flow guiding plate 12 are sealed by the front and rear inner side walls of the upper box outer shell 100, the high-speed air flow is guided to flow along the flow guiding plate 12, when the high-speed air flow flows out from the lower box 2 and flows out through the buffering and noise-reducing cavity 102, the flow guiding plate 12 flows upward on the two sides and contacts the 1/4 waveguide tube 11 for noise reduction, the high-speed air flow moves downwards from the upper opening of the guide plate 12 and then moves to the air outlet 10 to be discharged from the inner space of the guide plate 12.

In the embodiment of the present invention, as shown in fig. 3 and 7, the top of the impact silencing cavity 102 is sealed, and a plurality of outlet openings 103 are disposed at two ends of the top of the impact silencing cavity 102, the bottom of the upper inner casing 101 is communicated with the impact silencing cavity 102 through the outlet openings 103, the lower end of the flow guide plate 12 is fixedly connected to the outer wall of the top of the impact silencing cavity 102, because the two ends of the top of the impact silencing cavity 102 are disposed with the outlet openings 103 for air to flow out, the high-speed air flow can only flow out through-hole outlet openings 103 on the impact silencing cavity 102 at two sides of the lower end of the flow guide plate 12, the high-speed air flow is silenced and damped in the impact silencing cavity 102, and the front and rear sides of the flow guide plate 12 are blocked by the front and rear inner side walls of the upper outer casing 100, when the high-speed air flow flows out from the lower casing 2 and flows out through two ends of the impact silencing cavity 102, the high-speed air flows upwards from two sides of the outer part of the guide plate 12 and contacts with the 1/4 wave tube 11 to perform noise reduction treatment, so that the high-speed air flows downwards from the upper end opening of the guide plate 12 and then moves to the air outlet 10 to be discharged, and the high-speed air flows continuously contact with the 1/4 wave tube 11 to perform noise reduction treatment in the flowing process in the guiding flowing process of the inner space and the outer part of the guide plate 12.

According to another aspect of the present invention, with reference to fig. 1 to 6, the present invention provides a noise reduction method for a high-speed and high-pressure centrifugal blower, which mainly utilizes a noise reduction structure for a high-speed (50000r/min) and high-pressure (80KPa) centrifugal blower to reduce noise, and mainly includes the following steps: connecting the front side of the upper box body 1 with a high-speed high-pressure centrifugal blower and a connecting air outlet 10, and enabling high-speed air flow to sequentially enter an air outlet silencing cavity 21a and a resonant cavity 21 along an air inlet 20; after the high-speed air flow enters the air outlet silencing cavity 21a and is filtered by the grille net and the first filter plate 22, the high-speed air flow after being filtered passes through a V-shaped plate or herringbone silencing ventilation channel 25 formed by a plurality of layers of silencing channel plates 23 for primary noise reduction; the high-speed air that preliminarily made an uproar flows through resonant cavity 21, a plurality of connection dryer 3 upwards send into buffering amortization cavity 102 and carry out the amortization again and fall the noise, wind is the U-shaped, the lateral wall of V-arrangement or curved guide plate 12 continues to flow upwards, it is the 1/4 wave tube 11 contact of interval distribution installation to carry out the amortization with the left and right sides wall and the top of last incasement casing 101 respectively and falls the back of making an uproar, the inside wall that is the U-shaped at last, V-arrangement or curved guide plate 12 flows downwards and discharges from air outlet 10, get into high-speed high-pressure centrifugal blower. The noise reduction method of the high-speed (more than 50000r/min) high-pressure (more than 80KPa) centrifugal blower has the characteristics of large ventilation volume, small internal resistance and resistance, when external air is coarsely filtered by the first filter plate 22, then enters the V-shaped silencing channel plate or the herringbone silencing channel plate 23, then is finely filtered by the second filter plate 24, and then enters the cavity 21 of the resonant cavity in the lower box body 2, so that the air from the air inlet 20 can be cleaned, part of inlet air noise is eliminated, the internal noise is prevented from diffusing outwards, clean air enters the resonant cavity 21 of the lower box body 2, the volume of the resonant cavity 21 of the lower box body 2 is large, the resonant cavity 21 of the lower box body 2 is internally provided with the sound absorption element 20 (sound absorption material) for absorbing sound with different frequencies and different wavelengths, the majority of noise reduction is realized, the clean high-speed air enters the upper box body 1 through the connecting air duct 3, the high-speed air flows in the upper box body 1 along the guide of the outer space and the inner space of the guide plate 12, 1/4 wave length tubes 11 are arranged on the inner walls of two sides and the inner wall of the top of the upper box body 1, the high-speed air flowing along the guide of the outer space of the guide plate 12 contacts with the 1/4 wave length tube 11 to perform noise reduction, at least 3 1/4 wave length tubes are arranged according to the noise frequency design, the upper box body 1 performs grading treatment on different sections of wavelengths, mainly treats the noise in 2000Hz, 4000Hz and 6000Hz frequency bands respectively, plays an impedance role on a main noise source, the 1/4 wave length tube generates resistant sound to the noise in corresponding frequency bands, thereby eliminating the sound level of the original noise, the installation of the 1/4 wave length tube 11 can be replaced, is particularly suitable for medium-high frequency noise treatment, after the 1/4 wave length tube 11 is replaced according to different fans and noise frequencies, the ideal noise reduction effect can be achieved. The noise reduction structure (silencer) is arranged in a blower box body and is simple and easy to install, the noise reduction structure (silencer) is firstly arranged in the lower box body 1 and then arranged in the upper box body 2, and then the lower box body is arranged in the connecting air cylinder 3, after air enters from the air inlet 20 of the lower box body 2, high-speed air flows upwards and enters the upper box body 1, so that the length of a noise reduction pipeline is increased, the noise reduction area is increased, the flow velocity of the air in the noise reduction structure is strictly controlled (the flow velocity of the high-speed air flow entering the air inlet 20 is not more than 7 m/s), the flow velocity is reduced by 1/5 compared with that of the conventional blower volute air inlet, and a preliminary test is carried out on the high-speed high-pressure centrifugal blower structure, the noise reduction value can reach 30-35dB (A), and good noise reduction inhibition effects can be achieved.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be construed as the protection scope of the present invention.