CN111649009A

CN111649009A - Composite noise eliminator for air inlet of high-speed centrifugal fan

Info

Publication number: CN111649009A
Application number: CN202010570554.0A
Authority: CN
Inventors: 方健; 余知义; 吴立华; 董继勇
Original assignee: Nanjing Cigu Technology Co Ltd
Current assignee: Nanjing Cigu Technology Co Ltd
Priority date: 2020-06-22
Filing date: 2020-06-22
Publication date: 2020-09-11
Also published as: WO2021258432A1

Abstract

The invention discloses a composite noise eliminator for air inlet of a high-speed centrifugal fan, which comprises an inlet flange, a first divergent pipe, a second divergent pipe, a noise eliminator, an upper end cover, a lower end cover and an outlet flange, wherein the inlet flange is arranged at the top of the inlet flange; the small end of the first gradually-expanding pipe is connected with the inlet flange, the large end of the first gradually-expanding pipe is connected with one surface of the upper end cover, the muffler device is arranged between the upper end cover and the lower end cover, the other surface of the lower end cover is connected with the large end of the second gradually-expanding pipe, the small end of the second gradually-expanding pipe is connected with the outlet flange, and the outlet flange is connected with the air inlet end of the fan; the silencing device comprises a silencing channel and a shell, wherein the silencing channel is arranged in the shell and comprises a perforated plate, a facing layer and a sound absorption material, and the facing layer is positioned between the perforated plate and the sound absorption material; based on the expansion and resistance silencing principle, the invention effectively eliminates the noises of low, medium and high frequency bands, has wide silencing frequency band, solves the problem of high frequency failure of the conventional silencer, and has the advantages of simple structure, simple manufacturing process, easy manufacture, convenient maintenance and installation.

Description

Composite noise eliminator for air inlet of high-speed centrifugal fan

Technical Field

The invention relates to the field of fan noise control, in particular to a composite muffler device for air inlet of a high-speed centrifugal fan.

Background

The high-speed centrifugal fan is widely applied to industries such as medicine, environmental protection, chemical industry, petroleum and the like. The fan mainly has aerodynamic noise, mechanical noise, motor noise and basic vibration noise in the operation process, the noise has the characteristic of wide frequency, the noise energy of the middle and high frequency ranges is high, the air inlet noise mainly comes from fan impeller fundamental frequency noise and air inlet pulsating airflow sound or is caused by the mixing of the two, the air inlet pulsating airflow sound mainly has low frequency of 125Hz, 500Hz and 1000Hz, and the frequency ranges are more prominent, so that people are irritated and have abnormal pulse and heart. The prior high-speed centrifugal fan air inlet noise elimination technology has the following problems: 1. the noise elimination frequency band is narrow, the noise elimination quantity is low, and the manufacturing process is complex; 2. the serious problem of high-frequency failure, low noise of air inlet of the fan, and noise of middle and high frequency bands can not be effectively controlled.

Disclosure of Invention

The technical purpose is as follows: the invention discloses a composite silencer for high-speed centrifugal fan air inlet, which is simple in manufacturing process, high in high-frequency failure frequency, wide in silencing frequency band, large in silencing quantity and convenient to maintain and install, and aims to overcome the defects of the existing high-speed centrifugal fan air inlet silencing technology in silencing frequency band and structure.

The technical scheme is as follows: in order to achieve the technical purpose, the invention adopts the following technical scheme:

a composite muffler device for air inlet of a high-speed centrifugal fan comprises an inlet flange, a first divergent pipe, a second divergent pipe, a muffler device, an upper end cover, a lower end cover and an outlet flange; the first gradually-expanding pipe is connected with the inlet flange and the upper cover plate, and the noise eliminator is fixed between the upper cover plate and the lower cover plate; the second divergent pipe is connected with the lower cover plate and the outlet flange.

The silencing device comprises a shell and a silencing channel, wherein the silencing channel comprises a perforated plate, a protective layer and a sound absorbing material, the protective layer is positioned between the perforated plate and the sound absorbing material, the perforated plate is positioned on the innermost side of the silencing device, and the protective layer is pressed on the sound absorbing material; the perforated plate is provided with round holes which are uniformly arranged, and the perforated plate, the protective layer and the sound absorption material jointly form a composite sound absorption structure to effectively absorb the low-frequency pulsation noise of the air intake.

Preferably, the small end of the first gradually-expanding pipe is connected with the inlet flange, and the large end of the first gradually-expanding pipe is connected with the end face of the upper cover plate; the large end of the second gradually-expanding pipe is connected with the end face of the lower cover plate, and the small end of the second gradually-expanding pipe is fixedly connected with the outlet flange; the gradually expanding pipes at the two ends are based on an expansion silencing theory, so that an expansion structure for flow field optimization is facilitated, and pressure loss is effectively reduced; the low-frequency noise can be effectively reduced, meanwhile, the air flow is facilitated, the resistance loss of air is reduced, and the air inlet efficiency is ensured.

Preferably, the upper cover plate and the lower cover plate are provided with mounting holes matched with the shapes of the sections of the silencing channels to fix the silencing channels.

Preferably, the muffling channel cross-sectional shape includes, but is not limited to, the following forms: round, square, regular pentagon, regular hexagon, regular octagon, wherein regular hexagon is preferred; wherein the radius of the circumscribed circle of the silencing channel is 50 mm-250 mm, and the distance between the edges of the silencing channel is 20 mm-200 mm; the number of the silencing channels is 12-40; the high-frequency failure frequency of the silencing channel is high, the applicability to the air inlet broadband noise of the fan is high, and the silencing channel still has good silencing performance for high-frequency section noise.

Preferably, the sound absorption material is of a porous structure, can be superfine glass wool or polyurethane foam plastic, and is preferably superfine glass wool, and the thickness of the sound absorption material is 20 mm-150 mm; the bulk density is 20kg/m 3-50 kg/m3, and the water content is 0.2% -3%; the mass moisture absorption rate is 2% -8%, and the hydrophobic rate is more than or equal to 98%; the superfine glass wool has proper flow resistance, uniform pores, and higher sound absorption performance and chemical stability.

Preferably, the perforated plate material includes, but is not limited to: aluminum alloys, galvanized sheets, etc., preferably galvanized sheets; the aperture of the perforated plate is 0.5 mm-10 mm; the hole spacing is 2 mm-15 mm, the plate thickness of the perforated plate is 2 mm-5 mm, and the perforation rate is 10% -40%.

Preferably, the materials of the armor layer include, but are not limited to: glass fiber cloth, non-woven fabric and film, preferably glass fiber cloth.

When the invention is used, the outlet flange is connected with an inlet pipeline of the fan, and the inlet flange is connected with an air inlet pipeline; after the fan starts, the air passes through the inlet flange from the admission line, through first divergent pipe, along with the sectional area increase, and the gaseous velocity of flow reduces, and gaseous through noise eliminator gets into the second divergent pipe after fully eliminating the noise, and the sectional area reduces gradually, and the gaseous velocity of flow accelerates, gets into inside the fan through the outlet flange.

Has the advantages that: according to the composite noise elimination device for the air inlet of the high-speed centrifugal fan, the gradually expanding pipes are arranged at the two ends, and by utilizing an expansion noise elimination theory, low-frequency noise is effectively reduced, airflow flowing is facilitated, and resistance loss can be reduced; the high-frequency failure frequency of the silencing channel is high, the device is more applicable to the air inlet broadband noise of a fan, and the device still has good silencing performance on high-frequency section noise; the sound absorption material has good acoustic performance, proper flow resistance, uniform pores, higher sound absorption performance and chemical stability; when the perforated plate and the protective surface layer are used on the porous material, the middle and low frequency sound absorption coefficients can be improved to some extent, a composite sound absorption structure is effectively formed, and low frequency pulsation noise of inlet air is effectively absorbed; the silencer has wide silencing frequency band, solves the problem of high-frequency failure of the conventional silencer, has simple structure, simple manufacturing process, easy manufacture and convenient maintenance and installation, and can be used for eliminating the air inlet noise of fans of various types and models.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.

FIG. 1 is an overall block diagram of the present invention;

FIG. 2 is a cross-sectional view of the sound attenuating structure;

FIG. 3 is a cross-sectional view of the muffling channel;

FIG. 4 is a three-dimensional perspective view of a perforated plate of the muffling channel of FIG. 3;

FIG. 5 is a cross-sectional view of the perforated plate of the muffling channel of FIG. 3;

wherein: 1-inlet flange, 2-first divergent pipe, 3-second divergent pipe, 4-silencing device, 5-upper end cover, 6-lower end cover, 7-outlet flange, 8-silencing channel, 801-perforated plate, 802-protective layer, 803-sound-absorbing material and 9-shell.

Detailed Description

The present invention will be more clearly and completely described below by way of a preferred embodiment in conjunction with the accompanying drawings, without thereby limiting the scope of the invention to the described embodiment.

Fig. 1 shows a composite muffler device for air intake of a high-speed centrifugal fan, which comprises an inlet flange 1, a first divergent pipe 2, a second divergent pipe 3, a muffler device 4, an upper end cover 5, a lower end cover 6 and an outlet flange 7; the small end of the first gradually expanding pipe 2 is connected with the inlet flange 1, and the large end is connected with the upper end cover 5; the silencing device is fixed between the upper end cover 5 and the lower end cover 6; as shown in fig. 2, the muffler device includes a housing 9 and a muffler channel 8, the muffler channel 8 is arranged in parallel in the housing 9, and the cross-sectional shape of the muffler channel 8 is a regular hexagon.

Taking the example that the air intake of a fan is 210 m/min and the diameter of a pipeline at the inlet of the fan is D1=500mm, designing the noise reduction amount to be 40dB according to the highest noise energy of one meter measuring point at the inlet of the original fan, namely 101dB (A), the environmental noise standard and the noise reduction requirement, and determining the effective noise reduction section D2 to be 800 mm-2000 mm according to the expansion ratio R = D1/D2= 0.25-0.625; the effective silencing length L is 800 mm-3000 mm.

The silencing channel 8 is a composite silencing structure, as shown in fig. 3, and comprises a perforated plate 801, a protective layer 802 and a sound absorption material 803; the perforated plate 801 is preferably a galvanized plate, and the plate surface is uniformly provided with round holes which are positioned at the innermost side of the silencing passage 8, the perspective view is shown as 4, and the cross section view is shown as 5. The protective layer 802 is made of glass fiber cloth and is pressed on the sound absorption material 803 by the perforated plate 801, the perforated plate 801 and the protective layer 802 effectively form a composite sound absorption structure, and the sound absorption coefficients of medium and low frequencies are improved.

The sound absorption material 803 uses ultra-fine glass wool, and has good acoustic performance, proper flow resistance, uniform pores, and high sound absorption performance and chemical stability.

The upper end cover 5 and the lower end cover 6 are provided with mounting holes matched with the sections of the silencing passages 8 and used for fixing the silencing passages 8, the lower end cover 6 is connected with the large end of the second gradually expanding pipe 3, and the small end of the second gradually expanding pipe 3 is fixedly connected with the outlet flange 7.

The first gradually-expanding pipe 2 and the second gradually-expanding pipe 3 are respectively and oppositely arranged at two ends of the muffler device 4, low-frequency noise can be effectively reduced by utilizing an expansion muffling theory, air flow flowing is facilitated, resistance loss of air is reduced, air inlet efficiency is guaranteed, and meanwhile the muffling effect of the muffler device 4 can be improved.

The invention provides a composite silencer for air inlet of a high-speed centrifugal fan, which is characterized in that an inlet flange 1 is connected with an air inlet pipe, an outlet flange 7 is connected with an inlet of the fan, when the fan is started, air enters a first gradually-expanding pipe 2 through the air inlet pipe, the flow speed is reduced, the air passes through a silencing passage 8 of a silencer 4 and then enters a second gradually-expanding pipe 3, the flow speed is increased, and the air enters the fan through the outlet flange 7 to complete silencing.

The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.

Claims

1. The utility model provides a compound noise eliminator that high-speed centrifugal fan admitted air which characterized in that: comprises an inlet flange (1), a first gradually expanding pipe (2), a second gradually expanding pipe (3), a silencing device (4), an upper end cover (5), a lower end cover (6) and an outlet flange (7);

the small end of the first gradually-expanding pipe (2) is fixedly connected with the inlet flange (1), the large end of the first gradually-expanding pipe is connected with the upper end cover (5), the other surface of the upper end cover (5) is connected with the silencing device (4), the upper end surface and the lower end surface of the silencing device (4) are respectively connected with the upper end cover (5) and the lower end cover (6), the other surface of the lower end cover (6) is connected with the large end of the second gradually-expanding pipe (3), and the small end of the second gradually-expanding pipe (3) is connected with the outlet flange (7);

the noise elimination device (4) comprises a noise elimination channel (8) and a shell (9), wherein the noise elimination channel (8) is arranged in the shell (9); and a perforated plate (801), a protective layer (802) and a sound absorption material (803) are arranged on the side surface of the sound attenuation channel (8), and the protective layer (802) is positioned between the perforated plate (801) and the sound absorption material (803).

2. The composite muffler device for the air inlet of the high-speed centrifugal fan as claimed in claim 1, wherein: the silencing channels (8) are uniformly arranged in parallel in the shell (9), and two ends of the silencing channels are fixed through the upper end cover (5) and the lower end cover (6).

3. The composite muffler device for the air inlet of the high-speed centrifugal fan as claimed in claim 1, wherein: the edge distance of the silencing channel (8) is 20 mm-200 mm.

4. The composite muffler device for the air inlet of the high-speed centrifugal fan as claimed in claim 1, wherein: the radius of the circumcircle of the noise elimination channel (8) ranges from 50mm to 150mm, and the number of the noise elimination channels (8) ranges from 12 to 40.

5. The composite muffler device for the air inlet of the high-speed centrifugal fan as claimed in claim 1, wherein: the cross section of the silencing channel (8) is one of a circle, a square, a regular pentagon, a regular hexagon and a regular octagon.

6. The composite muffler device for the air inlet of the high-speed centrifugal fan as claimed in claim 1, wherein: the sound absorption material (803) is made of one of superfine glass wool or polyurethane foam plastic, the thickness of the sound absorption material is 20 mm-150 mm, and the bulk weight of the sound absorption material is 20kg/m and 50kg/m for carrying out thin-wall high-speed thin-wall.

7. The composite muffler device for the air inlet of the high-speed centrifugal fan as claimed in claim 6, wherein: the water content of the sound absorption material (803) is 0.2-3%, the mass moisture absorption rate is 2-8%, and the hydrophobic rate is more than or equal to 98%.

8. The composite muffler device for the air inlet of the high-speed centrifugal fan as claimed in claim 1, wherein: the material of the protective layer (802) is one of glass fiber cloth, non-woven fabric and thin film.

9. The composite muffler device for the air inlet of the high-speed centrifugal fan as claimed in claim 1, wherein: the perforated plate (801) is made of one of aluminum alloy or galvanized plates and is provided with small holes which are uniformly distributed, the aperture is 0.5 mm-10 mm, and the perforation rate is 10% -40%.

10. The composite muffler device for the air inlet of the high-speed centrifugal fan as claimed in claim 9, wherein: the thickness of the perforated plate (801) is 2 mm-5 mm.