Low-noise centrifugal fan

Abstract

The invention provides a low-noise centrifugal fan, relates to the technical field of centrifugal fans, and aims to solve the technical problem of high noise of a centrifugal fan in the prior art. A low-noise centrifugal fan comprises a volute, an air outlet is formed in the volute, a plurality of noise reduction through holes are formed in the peripheral wall of the volute, the noise reduction through holes are distributed in the peripheral direction of the peripheral wall of the volute in an array mode, a noise reduction cover is connected to the peripheral wall of the volute, and a noise reduction layer is arranged between the noise reduction cover and the peripheral wall of the volute. The noise reduction layer is arranged in the circumferential direction of the outer circumferential wall of the volute and covers all the noise reduction through holes. The noise reduction layer is formed by pressing at least one noise reduction material. A better noise reduction effect is achieved through the combined action of the volute, the noise reduction through holes and the noise reduction layer, and the requirement for use of a low-environment-noise ventilation and air conditioning system is met.

Description

Technical Field

[0001] The invention relates to the technical field of centrifugal fans, in particular to a low-noise centrifugal fan. Background Art

[0002] The centrifugal fan mainly includes an impeller, a volute and a motor. The impeller is the main working component that generates wind pressure and transmits energy; the volute is mainly used to introduce and exhaust gas, and at the same time convert part of the kinetic energy of the gas into pressure energy. The working principle of the centrifugal fan is mainly to generate centrifugal force through the high-speed rotation of the impeller, and throw the gas from the center of the impeller to the volute, so that the gas gains kinetic energy and pressure energy. Driven by the impeller, the gas leaves the impeller in the radial direction and relies on the centrifugal force generated to do work. When the gas flows through the impeller, it changes to radial direction and enters the diffuser. The cross-section of the diffuser gradually expands, converting part of the kinetic energy into pressure energy, so that the outlet gas has a certain pressure energy and is transported out.

[0003] In low-noise ventilation and air-conditioning systems, the noise requirements for centrifugal fans are high. Ordinary centrifugal fans generally reduce noise by reducing the fan speed, but low noise cannot be achieved in places with high noise requirements. Summary of the invention

[0004] In view of the deficiencies of the prior art, an object of the present invention is to provide a low-noise centrifugal fan to solve the technical problem of high noise of the centrifugal fan in the prior art.

[0005] In order to solve the above technical problems, the present invention provides a low-noise centrifugal fan, including a volute, which is provided with an air outlet, wherein a plurality of noise reduction through holes are provided on the outer peripheral wall of the volute, and the noise reduction through holes are distributed in an array along the circumferential direction of the outer peripheral wall of the volute, and a soundproof cover is connected to the outer peripheral wall of the volute, and a soundproofing layer is provided between the soundproofing cover and the outer peripheral wall of the volute, and the soundproofing layer is arranged along the circumferential direction of the outer peripheral wall of the volute and covers all the noise reduction through holes, and the soundproofing layer is pressed from at least one soundproofing material.

[0006] After adopting the above structure, the low-noise centrifugal fan of the present invention has the following advantages: when the low-noise centrifugal fan is working, when the noise wave generated by the air flow in the volute is projected into the surface of the volute, a part of it will be reflected back by the surface of the volute, thereby reducing the propagation of the noise. At the same time, the noise reduction through hole causes the reflected noise wave to be refracted and diffracted differently, thereby achieving the effect of noise reduction, and part of the noise wave propagated out from the noise reduction through hole is absorbed by the sound-absorbing layer made of sound-absorbing material, thereby also achieving the effect of noise reduction. The present invention achieves a better noise reduction effect through the combined action of the volute, the noise reduction through hole and the sound-absorbing layer, thereby meeting the use of ventilation and air-conditioning systems with low environmental noise.

[0007] As an improvement, a closed accommodating chamber is provided between the silencer hood and the outer peripheral wall of the volute, and the sound-absorbing layer is arranged in the accommodating chamber. With this structure, a closed accommodating chamber is formed by the silencer hood and the outer peripheral wall of the volute, and the sound-absorbing layer is arranged in the accommodating chamber, so that the silencer hood can also play a role in noise reduction, thereby further improving the noise reduction effect.

[0008] As an improvement, the silencer hood includes a circumferential portion, a front partition, a rear partition, a first end partition and a second end partition. The circumferential portion is arranged along the outer peripheral wall of the volute, the front partition and the rear partition are respectively arranged at the front and rear ends of the circumferential portion, the first end partition and the second end partition are respectively arranged at the two ends of the circumference of the circumferential portion, the front partition, the rear partition, the first end partition and the second end partition are all connected to the outer peripheral wall of the volute, and the front partition, the rear partition, the first end partition, the second end partition and the circumferential portion are surrounded to form a accommodating cavity; with this structure, the circumferential portion, the front partition, the rear partition, the first end partition and the second end partition of the silencer hood can also play a role in isolating and reducing noise, further improving the noise reduction effect.

[0009] As an improvement, the first end baffle and the second end baffle are both provided with connecting plates, and the two connecting plates are connected to the outer peripheral wall of the volute by bolts; this structure has the advantages of simple structure and convenient connection.

[0010] As an improvement, the sound-absorbing layer includes a first sound-absorbing layer and a second sound-absorbing layer from the inside to the outside, and the density of the second sound-absorbing layer is greater than the density of the first sound-absorbing layer. With this structure, the noise is absorbed layer by layer by arranging the first sound-absorbing layer and the second sound-absorbing layer with increasing density, thereby further improving the noise reduction effect.

[0011] As an improvement, the first sound-absorbing layer is pressed from glass fiber yarns, and the second sound-absorbing layer is pressed from felt. With this structure, the first sound-absorbing layer made of glass fiber yarns and the second sound-absorbing layer made of felt absorb the energy of sound waves, thereby reducing the reflection and propagation of sound waves and further improving the noise reduction effect.

[0012] As an improvement, the cross-section of the noise reduction through holes is circular, the aperture of the noise reduction through holes is 3 mm, and the perforation rate of the outer wall of the vortex casing is 1.6%; this structure is adopted to further improve the noise reduction effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a partial cross-sectional schematic diagram of the present invention.

[0014] Figure 2 It is a schematic diagram of the three-dimensional structure of the present invention.

[0015] Figure 3 It is a schematic diagram of the three-dimensional structure of the volute part in the present invention.

[0016] Figure 4It is a schematic diagram of the three-dimensional structure of the muffler cover part of the present invention.

[0017] Figure 5 It is a schematic diagram of the three-dimensional structure of the sound-absorbing layer in the present invention.

[0018] Figure numerals: 1. volute; 2. air outlet; 3. noise reduction through hole; 4. silencer cover; 41. circumferential portion; 42. front partition; 43. rear partition; 44. first end partition; 45. second end partition; 46. connecting plate; 5. silencer layer; 6. accommodating chamber; 7. motor; 8. impeller. DETAILED DESCRIPTION

[0019] The low noise centrifugal fan of the present invention is described in detail below with reference to the accompanying drawings.

[0020] like Figures 1 to 5 As shown, a low-noise centrifugal fan includes a volute 1, which is provided with an air outlet 2, wherein the air outlet 2 is arranged on the outer wall of the volute 1, a motor 7 is connected to the end face of the volute 1, and a plurality of impellers 8 are circumferentially arranged in the inner cavity of the volute 1. The specific arrangement of the air outlet 2, the motor 7 and the impeller 8 is the same as that in the prior art and will not be repeated here.

[0021] like Figure 1 and Figure 3 As shown, a plurality of noise reduction through holes 3 are provided on the outer peripheral wall of the volute 1. The noise reduction through holes 3 are distributed in an array along the circumferential direction of the outer peripheral wall of the volute 1 and are only distributed on the outer peripheral wall of the volute 1. No noise reduction through holes 3 are provided on the two opposite end faces of the volute 1.

[0022] like Figure 1 As shown, a silencer cover 4 is connected to the outer peripheral wall of the volute 1, and a silencer layer 5 is provided between the silencer cover 4 and the outer peripheral wall of the volute 1. The silencer layer 5 is arranged circumferentially along the outer peripheral wall of the volute 1 and covers all noise reduction through holes 3. The silencer layer 5 is pressed from at least one silencer material.

[0023] like Figure 4As shown, a closed accommodating chamber 6 is provided between the silencer cover 4 and the outer peripheral wall of the volute 1, and the silencer layer 5 is provided in the accommodating chamber 6; specifically, the silencer cover 4 includes a circumferential portion 41, a front baffle 42, a rear baffle 43, a first end baffle 44 and a second end baffle 45, the circumferential portion 41 is provided along the outer peripheral wall of the volute 1, the front baffle 42 and the rear baffle 43 are provided at the front and rear ends of the circumferential portion 41, the first end baffle 44 and the second end baffle 45 are provided at the circumferential ends of the circumferential portion 41, the front baffle 42, the rear baffle 43, the first end baffle 44 and the second end baffle 45 are all connected to the outer peripheral wall of the volute 1 The front partition 42, the rear partition 43, the first end partition 44, the second end partition 45 and the circumferential portion 41 together form a accommodating chamber 6, wherein the front partition 42 and the rear partition 43 are both arranged on the front and rear sides of the circumferential portion 41 along the circumferential direction of the circumferential portion 41, and the circumferential portion 41 covers all the noise reduction through holes 3. That is to say, after the silencer 4 is connected to the volute 1, all the noise reduction through holes 3 are located in the accommodating chamber 6, and the front partition 42, the rear partition 43, the first end partition 44 and the second end partition 45 are all attached to the outer peripheral wall of the volute 1, and the sound-absorbing layer 5 fills the entire accommodating chamber 6.

[0024] In addition, if Figure 4 As shown, the first end baffle 44 and the second end baffle 45 are both provided with a connecting plate 46 , and the two connecting plates 46 are connected to the outer peripheral wall of the volute 1 by bolts. Similarly, the two connecting plates 46 are also attached to the outer peripheral wall of the volute 1 .

[0025] The sound-absorbing layer 5 includes a first sound-absorbing layer and a second sound-absorbing layer from the inside to the outside. The density of the second sound-absorbing layer is greater than that of the first sound-absorbing layer. In this embodiment, the first sound-absorbing layer is pressed from glass fiber yarns, and the second sound-absorbing layer is pressed from felt. In some other embodiments, a third sound-absorbing layer or even more sound-absorbing layers may be further provided on the basis of the first sound-absorbing layer and the second sound-absorbing layer. The sound-absorbing material is a material with a high sound absorption coefficient. In addition to the above two types, materials such as foam plastics may also be selected.

[0026] When the gas passes through the portion of the volute 1 provided with the noise reduction through hole 3, the gas flow rate will increase, thereby causing the gas pressure to decrease. This pressure drop is controlled by the geometric shape and aperture size of the noise reduction through hole 3. In the present embodiment, the cross-section of the noise reduction through hole 3 is circular, the aperture of the noise reduction through hole 3 is 3 mm, the perforation rate of the outer wall of the volute 1 is 1.6%, and the thickness of the outer wall of the volute 1 is 1.2 mm, thereby producing a better noise reduction effect.

[0027] When the low-noise centrifugal fan is working, when the noise wave generated by the air flow in the volute 1 is projected into the surface of the volute 1, a part of it will be reflected back by the surface of the volute 1, thereby reducing the propagation of the noise. At the same time, the noise reduction through hole 3 causes the reflected noise wave to be refracted and diffracted differently, thereby achieving the effect of noise reduction, and part of the noise wave propagated out from the noise reduction through hole 3 is absorbed by the sound-absorbing layer 5 made of sound-absorbing material, thereby also achieving the effect of noise reduction. In addition, in addition to being used to fix the sound-absorbing layer 5, the sound-absorbing cover 4 can also play a certain role in isolating the noise. The present invention achieves a better noise reduction effect through the combined action of the volute 1, the noise reduction through hole 3, the sound-absorbing layer 5 and the sound-absorbing cover 4, thereby meeting the use of ventilation and air-conditioning systems with low environmental noise.

[0028] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned one embodiment, and all other embodiments obtained by those skilled in the art without making any creative work are within the scope of protection of the present invention.

Claims

1. A low-noise centrifugal fan, comprising a volute (1), wherein the volute (1) is provided with an air outlet (2), characterized in that: The outer wall of the volute (1) is provided with a plurality of noise reduction through holes (3), the noise reduction through holes (3) are distributed in an array along the circumferential direction of the outer wall of the volute (1), a silencer cover (4) is connected to the outer wall of the volute (1), a silencer layer (5) is provided between the silencer cover (4) and the outer wall of the volute (1), the silencer layer (5) is provided along the circumferential direction of the outer wall of the volute (1) and covers all the noise reduction through holes (3), and the silencer layer (5) is formed by pressing at least one silencer material.

2. The low noise centrifugal fan according to claim 1, characterized in that: A closed accommodating chamber (6) is provided between the silencer cover (4) and the outer peripheral wall of the volute (1), and the silencer layer (5) is provided in the accommodating chamber (6).

3. The low noise centrifugal fan according to claim 2, characterized in that: The silencer cover (4) comprises a circumferential portion (41), a front baffle (42), a rear baffle (43), a first end baffle (44) and a second end baffle (45); the circumferential portion (41) is arranged along the outer peripheral wall of the volute (1); the front baffle (42) and the rear baffle (43) are respectively arranged at the front and rear ends of the circumferential portion (41); the first end baffle (44) and the second end baffle (45) are respectively arranged at the circumferential ends of the circumferential portion (41); the front baffle (42), the rear baffle (43), the first end baffle (44) and the second end baffle (45) are all connected to the outer peripheral wall of the volute (1); the front baffle (42), the rear baffle (43), the first end baffle (44), the second end baffle (45) and the circumferential portion (41) together form the accommodating cavity (6).

4. The low noise centrifugal fan according to claim 3, characterized in that: The first end baffle (44) and the second end baffle (45) are both provided with a connecting plate (46), and the two connecting plates (46) are connected to the outer peripheral wall of the volute (1) by bolts.

5. The low noise centrifugal fan according to claim 1, characterized in that: The sound-absorbing layer (5) comprises, from the inside to the outside, a first sound-absorbing layer and a second sound-absorbing layer, wherein the density of the second sound-absorbing layer is greater than the density of the first sound-absorbing layer.

6. The low noise centrifugal fan according to claim 5, characterized in that: The first sound-absorbing layer is formed by pressing glass fiber yarns, and the second sound-absorbing layer is formed by pressing felt.

7. The low noise centrifugal fan according to claim 1, characterized in that: The cross-section of the noise reduction through holes (3) is circular, the aperture of the noise reduction through holes (3) is 3 mm, and the perforation rate of the outer peripheral wall of the volute (1) is 1.6%.

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