A noise reduction device and noise reduction method for an exhaust pipe of a magnetic levitation vacuum pump

Abstract

The invention discloses a noise reduction device and a noise reduction method for an exhaust pipe of a magnetic levitation vacuum pump. The noise reduction device comprises a gradual noise reduction pipe, one end of the gradual noise reduction pipe is connected to the exhaust pipe through an air intake straight pipe, and the other end is connected to an air outlet straight pipe; along the exhaust flow direction, the diameter of the gradual noise reduction pipe gradually increases, a diverter noise reduction plate is provided in the gradual noise reduction pipe along the axial direction, the diverter noise reduction plate divides the gradual noise reduction pipe into two independent noise reduction channels, and a plurality of guide vanes are provided on the surface of the diverter noise reduction plate on a side close to the air intake straight pipe along the air intake direction; the gradual noise reduction pipe of the invention uses the diverter noise reduction plate to divide the pipe into two noise reduction channels, sound energy can be effectively dissipated in the channels, air flow pulsation is small, thereby reducing exhaust noise; the arc structure of the guide vane effectively reduces the original BPF noise level, reduces the secondary harmonic, makes the noise broadband, and improves the noise reduction effect.

Description

Technical Field

[0001] The present invention relates to the technical field of silencing and noise reduction equipment, and in particular to a noise reduction device and a noise reduction method for an exhaust pipeline of a magnetic levitation vacuum pump. Background Art

[0002] Due to the characteristics of high speed, large exhaust flow, high noise level radiated by the outlet pipe, wide frequency band and large noise pollution of the suspended vacuum pump, it is difficult to effectively eliminate the high-frequency noise even if the existing pipe is wrapped. At the same time, the sound insulation is limited. Adding a silencer structure inside the pipe will affect the exhaust and cause greater resistance loss. Summary of the invention

[0003] Technical purpose: In view of the shortcomings of the above-mentioned existing exhaust pipe silencers, the present invention discloses a magnetic levitation vacuum pump exhaust pipe noise reduction device and noise reduction method.

[0004] Technical solution: To achieve the above technical objectives, the present invention adopts the following technical solution:

[0005] A noise reduction device for an exhaust pipe of a magnetic levitation vacuum pump comprises a gradual muffler pipe, one end of the gradual muffler pipe is connected to an exhaust pipe through an air intake straight pipe, and the other end is connected to an air outlet straight pipe; along the exhaust flow direction, the diameter of the gradual muffler pipe gradually increases, a diverter muffler plate is provided in the gradual muffler pipe along the axial direction, the diverter muffler plate divides the gradual muffler pipe into two independent muffler channels, and a plurality of guide vanes are provided on the surface of the diverter muffler plate along the air intake direction on the side close to the air intake straight pipe.

[0006] Preferably, the ratio of the diameter of the air inlet end to the air outlet end of the gradual silencer pipe of the present invention is d1 / d2=k, and the value of k is 0.6~1.

[0007] Preferably, the guide vane of the present invention adopts an arc structure arranged along the airflow direction, including a first arc segment located on the outside and a second arc segment located on the inside, the blade thickness between the first arc segment and the second arc segment gradually increases in the direction away from the diversion silencer, and rounded corners are used at the ends of the first arc segment and the second arc segment for transition.

[0008] Preferably, the first arc segment of the present invention adopts an arc structure, with the convex surface facing the air inlet side; the radius of the first arc segment a=m*d2 / 2; m is a correction coefficient, which is 0.2-0.6, and the central angle corresponding to the arc length of the first arc segment is , , where r is the rated speed of the vacuum pump in working condition, and N is the number of blades of the rotating impeller.

[0009] Preferably, the second arc segment of the present invention includes a first arc segment and a second arc segment, b of the first arc segment is n*d1 / 2; n is a correction coefficient, which is 0.3 to 0.8, and the central angle corresponding to the arc length of the first arc segment is , ; The second arc segment is tangent to the first arc segment and the fillet.

[0010] Preferably, the radius d of the rounded corner of the present invention is i =d0*lg(Nr / 60)*(2k+1),d0= t*(d2-d1) / 2 ;t is the correction coefficient, ranging from 0.1 to 0.8, where i represents the number of the guide vane along the inlet direction, ranging from 1 to j, j is the total number of guide vanes, k=i-1, d i Indicates the fillet radius corresponding to the i-th guide vane.

[0011] Preferably, the guide vanes of the present invention are arranged alternately and spaced along the air intake direction on two surfaces of the splitter silencer plate.

[0012] Preferably, a sound-absorbing structure is provided on the pipe wall of the gradual sound-absorbing pipe of the present invention.

[0013] The present invention discloses a method for reducing the noise of an exhaust pipe of a magnetic levitation vacuum pump. By using the noise reduction device, the gas in the exhaust pipe of the magnetic levitation vacuum pump enters a gradient silencer pipe from an air intake straight pipe, the airflow is separated by a shunting silencer sheet and enters a silencer channel of the gradient silencer pipe, the guide vanes rectify the intake air to eliminate the inlet flow distortion caused by the cross flow, and the silencer structure of the gradient silencer pipe is used to silence and reduce the noise of the intake air, and finally the gas is discharged from the air outlet straight pipe.

[0014] Beneficial effects: The noise reduction device and noise reduction method for the exhaust pipe of a magnetic levitation vacuum pump provided by the present invention have the following beneficial effects:

[0015] 1. The two ends of the gradual silencer pipe of the present invention are butt-jointed through straight pipes, which can reduce the steps of the gas flow channel, reduce resistance loss, and ensure exhaust efficiency while silencing.

[0016] 2. The gradient muffler pipe of the present invention uses a diverter muffler sheet to separate the pipe into two muffler channels, so that the sound energy can be effectively dissipated in the channel, and the air flow pulsation is small, thereby reducing the exhaust noise.

[0017] 3. The present invention improves the aerodynamic noise caused by the steady non-uniform flow of the rotating gas of the fluid through the arc structure of the guide vane, eliminates the inlet flow distortion caused by the cross flow of the inlet airflow, effectively reduces the original BPF noise level, reduces the second harmonic, makes the noise broadband, and has a good barrier to the noise in the medium and high frequency bands, solving the problem of poor sound insulation effect of pipeline wrapping. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0019] Figure 1 This is a cross-sectional view of the gradual muffler pipe structure of the present invention;

[0020] Figure 2 This is a schematic diagram of the guide blade structure of the present invention;

[0021] Figure 3 A comparison diagram of the noise spectrum of the present invention and the noise spectrum of the existing exhaust pipe;

[0022] Among them, 1-gradient silencer pipe, 2-inlet straight pipe, 3-outlet straight pipe, 4-diversion silencer plate, 5-guide blade, 6-first arc segment, 7-second arc segment, 8-rounded corner, 9-first circular arc segment, 10-second circular arc segment. DETAILED DESCRIPTION

[0023] Reference will now be made in detail to embodiments of the present disclosure, one or more examples of which are set forth herein below. Each embodiment and example is provided by explaining the apparatus, composition and materials of the present disclosure, rather than limiting. On the contrary, the following description provides a convenient illustration of an exemplary embodiment for implementing the present disclosure. In fact, it will be clear to those skilled in the art that various modifications and variations can be made in the teachings of the present disclosure without departing from the scope or spirit of the present disclosure. For example, a feature shown or described as a part of an embodiment can be used in conjunction with another embodiment to produce yet another embodiment. It is expected that the present disclosure covers such modifications and variations within the scope of the appended claims and their equivalents. Other objects, features and aspects of the present disclosure are disclosed in or clear from the following detailed description. It will be understood by those of ordinary skill in the art that this discussion is only a description of exemplary embodiments and is not intended to limit the wider aspects of the present disclosure.

[0024] like Figure 1-Figure 2 As shown, the present invention discloses a noise reduction device for the exhaust pipe of a magnetic levitation vacuum pump, comprising a gradual silencer pipe 1, one end of the gradual silencer pipe 1 is connected to the exhaust pipe through an air intake straight pipe 2, and the other end is connected to an air outlet straight pipe 3; along the exhaust flow direction, the diameter of the gradual silencer pipe 1 gradually increases, and a diverter silencer plate 4 is provided in the gradual silencer pipe 1 along the axial direction, and the diverter silencer plate 4 divides the gradual silencer pipe 1 into two independent silencer channels, and a plurality of guide blades 5 are provided on the surface of the diverter silencer plate 4 along the air intake direction on the side close to the air intake straight pipe 2.

[0025] The high-speed and high-pressure airflow in the exhaust duct is divided into two parts at the air inlet straight pipe 2, and the sound energy is effectively dissipated in the two silencer channels; in a specific embodiment, the ratio of the diameter of the air inlet end to the air outlet end of the gradient silencer duct 1 of the present invention is d1 / d2=k, and the value of k is 0.6~1, preferably 0.8.

[0026] The guide vane 5 of the present invention adopts an arc structure arranged along the airflow direction, including a first arc segment 6 located on the outside and a second arc segment 7 located on the inside. The blade thickness between the first arc segment 6 and the second arc segment 7 gradually increases in the direction away from the diversion silencer 4, and a rounded corner 8 is used at the ends of the first arc segment 6 and the second arc segment 7 for transition; the structure of the guide vane 5 can improve the aerodynamic noise caused by the steady non-uniform flow of the rotating gas of the fluid, reduce the second harmonic, and make the noise broadband; the silencer structure is set in conjunction with the pipe wall of the gradual silencer pipe 1 to effectively eliminate the exhaust noise.

[0027] The sound-absorbing structure of the present invention comprises a sound-insulating layer, a damping vibration-isolating layer and a sound-insulating layer arranged in sequence from outside to inside to form a composite sound-insulating structure; the sound-absorbing layer is composed of a sound-absorbing material layer and a perforated protective layer, and the sound-absorbing material is fixed by the perforated protective layer.

[0028] In order to further improve the noise reduction effect, the present invention arranges the guide blades 5 on the two surfaces of the split silencer sheet 4 along the air intake direction in an alternating manner, and adopts different structural designs for the guide blades at different positions, such as Figure 2 As shown, the first arc segment 6 of the present invention adopts an arc structure, with the convex surface facing the air inlet side; the radius of the first arc segment 6 is a=m*d2 / 2; m is a correction coefficient, which is 0.2~0.6, preferably 0.3; the central angle corresponding to the arc length of the first arc segment 6 is , , where r is the rated speed of the vacuum pump in working condition, and N is the number of blades of the rotating impeller.

[0029] The second arc segment 7 includes a first arc segment 9 and a second arc segment 10, wherein b of the first arc segment 9 is n*d1 / 2; n is a correction coefficient, which is 0.3 to 0.8, preferably 0.5; the central angle corresponding to the arc length of the first arc segment 9 is , The second arc segment 10 is tangent to the first arc segment 9 and the fillet 8, and the radius is e; the radius of the fillet 8 of the present invention is d i =d0*lg(Nr / 60)*(2k+1),d0= t*(d2-d1) / 2 ;t is the correction coefficient, ranging from 0.1 to 0.8, preferably 0.5; where i represents the number of the guide vane along the air inlet direction, ranging from 1 to j, j is the total number of guide vanes, k=i-1, d i Indicates the fillet radius corresponding to the i-th guide vane.

[0030] By setting guide vanes of different structures, the noise energy of harmonics can be effectively eliminated, making the noise broadband; at the same time, the guide vanes can be designed according to the operation of the magnetic levitation vacuum pump to ensure the noise elimination effect, such as Figure 3 As shown, by setting the noise reduction device of the present invention in the exhaust duct, the inlet flow distortion caused by the cross flow of the inlet airflow can be eliminated, the original BPF noise level can be effectively reduced, the second harmonic can be reduced, the noise can be broadbanded, and the noise reduction and silencing effect can be improved.

[0031] The present invention discloses a method for reducing the noise of an exhaust pipe of a magnetic levitation vacuum pump based on the structure of the noise reduction device. The gas in the exhaust pipe of the magnetic levitation vacuum pump enters a gradient silencer pipe from an air intake straight pipe, and the airflow is separated by a diversion silencer sheet and enters a silencer channel of the gradient silencer pipe. The guide vanes rectify the intake air to eliminate inlet flow distortion caused by cross flow, and the silencer structure of the gradient silencer pipe is used to silence and reduce the noise of the intake air. Finally, the gas is discharged from the air outlet straight pipe, so that the gas noise energy in the exhaust pipe is effectively reduced after passing through the gradient silencer pipe.

Claims

1. A noise reduction device for an exhaust pipe of a magnetic levitation vacuum pump, characterized in that: The invention comprises a gradual muffler pipe (1), one end of which is connected to an exhaust pipe via an intake straight pipe (2), and the other end of which is connected to an exhaust straight pipe (3); the diameter of the gradual muffler pipe (1) gradually increases along the exhaust flow direction; a flow splitter muffler sheet (4) is provided in the gradual muffler pipe (1) along the axial direction; the flow splitter muffler sheet (4) divides the gradual muffler pipe (1) into two independent muffler channels; a plurality of guide vanes (5) are provided on the surface of the flow splitter muffler sheet (4) on the side close to the intake straight pipe (2) along the intake direction. ), the guide blades (5) are arranged alternately and spaced along the air intake direction on two surfaces of the flow-dividing silencer plate (4); the guide blades (5) adopt an arc structure arranged along the airflow direction, comprising a first arc segment (6) located on the outside and a second arc segment (7) located on the inside, the blade thickness between the first arc segment (6) and the second arc segment (7) gradually increases in a direction away from the flow-dividing silencer plate (4), and a rounded corner (8) is used for transition at the ends of the first arc segment (6) and the second arc segment (7) away from the flow-dividing silencer plate (4).

2. A magnetic levitation vacuum pump exhaust pipe noise reduction device according to claim 1, characterized in that: The ratio of the diameter of the air inlet end to the air outlet end of the gradient muffler pipe (1) is d1 / d2=k, and the value of k is 0.6-1.

3. A magnetic levitation vacuum pump exhaust pipe noise reduction device according to claim 1, characterized in that: The wall of the gradual noise reduction pipe (1) is provided with a noise reduction structure.

4. A method for reducing noise in the exhaust pipe of a magnetic levitation vacuum pump, using the noise reduction device according to claim 3, characterized in that: The gas in the exhaust pipe of the magnetic levitation vacuum pump enters the gradual silencer pipe from the straight intake pipe. The airflow is separated by the diversion silencer sheet and enters the silencer channel of the gradual silencer pipe. The guide vanes rectify the intake air to eliminate the inlet flow distortion caused by the cross flow. The silencer structure of the gradual silencer pipe is used to silence and reduce the noise of the intake air. Finally, the gas is discharged from the straight outlet pipe.

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