A low-resistance rectifier silencer

Abstract

The present invention belongs to the field of pipeline silencer and specifically discloses a low-resistance rectifier silencer, which includes an outer tube, an inlet cannula, an outer perforated tube, an outlet cannula, an inner perforated tube and a rectifier tube, wherein: the inlet cannula, the outer perforated tube and the outlet cannula are connected in sequence and are all located inside the outer tube; the outer side of the inlet cannula, the outer perforated tube and the outlet cannula are filled with sound-absorbing material between the outer tube and the outer tube; the inlet cannula is a tapered gradually diverging tube, and the outlet cannula is a tapered gradually converging tube; the rectifier tube is a tapered gradually diverging tube with a closed inlet, which is located at the center of the device axis and close to the inlet side; the inner perforated tube is connected to the rectifier tube, and a rectifier cavity is formed in the inner perforated tube and the rectifier tube; multiple holes are opened on the inner perforated tube and the outer perforated tube, and the inner perforated tube and the outer perforated tube are coaxially arranged. The device of the present invention can effectively improve the sound attenuation while ensuring low resistance performance and reducing the frequency limit of the expansion cavity, and has a simple structure and is easy to manufacture.

Description

Technical Field

[0001] The present invention belongs to the field of pipeline silencer, and more specifically, relates to a low-resistance rectifying silencer. Background Art

[0002] A silencer is a device that attenuates or reflects noise inside a fluid pipeline that also transmits noise. In order to reduce the noise of the pipeline system, a low-resistance rectifying silencer is arranged in the inter-port flow channel of the centralized cooling system to control the noise of the pipeline system, while taking into account the low-resistance design requirements of the gravity operation of the centralized cooling system. Existing reactive silencers are mainly used for low-frequency silencing. Resistive silencers have good high-frequency sound absorption effects but have large flow resistance. Micro-perforated silencers still have certain limitations in terms of pass-through frequency. The impedance composite silencer can increase the sound absorption of the overall frequency band, but there will still be problems with the pass-through frequency and large flow resistance.

[0003] In view of this, there is an urgent need for a noise reduction structure that not only meets the noise reduction requirements of the entire frequency band, but also meets the low resistance requirements of operation. Summary of the Invention

[0004] In response to the above defects or improvement needs of the prior art, the present invention provides a low-resistance rectifier silencer, the purpose of which is to control the silencer of the pipeline system, while increasing the silencer volume and taking into account the low-resistance requirements of the gravity operation of the centralized cooling system.

[0005] To achieve the above object, according to one aspect of the present invention, a low-resistance rectifying muffler is provided, comprising an outer tube, an inlet cannula, an outer perforated tube, an outlet cannula, an inner perforated tube and a rectifying tube, wherein:

[0006] The inlet cannula, the outer perforated tube, and the outlet cannula are connected in sequence and are all located inside the outer tube. The outer side of the inlet cannula, the outer perforated tube, and the outlet cannula are integrally formed, and the space between the outer side and the outer tube is filled with sound-absorbing material. The inlet cannula is a tapered gradually expanding tube, and the outlet cannula is a tapered gradually converging tube.

[0007] The rectifier tube is a conical, gradually expanding tube with a closed inlet, which is located at the center of the device axis and close to the inlet side of the device; the inner perforated tube is connected to the rectifier tube, and a rectifier cavity is formed inside the inner perforated tube and the rectifier tube; multiple holes are opened on the inner perforated tube and the outer perforated tube, and the inner perforated tube and the outer perforated tube are coaxially arranged.

[0008] As a further preference, the effective length of the inlet cannula is 0.5L, and the effective length of the outlet cannula is 0.25L, where L is the effective length of the outer tube, and the effective length refers to the length in the axial direction of the device.

[0009] As a further preference, the inlet cannula and the outlet cannula both have rigid tube walls; the inlet cannula and the corresponding area of ​​the outer tube form a 1 / 4 resonance cavity, and the outlet cannula and the corresponding area of ​​the outer tube form a 1 / 4 resonance cavity.

[0010] As a further preference, the diffusion angle of the inlet cannula is 10° to 14°, and the contraction angle of the outlet cannula is 10° to 40°.

[0011] As a further preference, the ratio of the area of ​​the inlet cannula at the outlet to the area of ​​the inlet is 2:1 to 6:1, and the ratio of the area of ​​the outlet cannula at the inlet to the area of ​​the outlet is 2:1 to 6:1.

[0012] As a further preference, the perforation rates of the inner perforated tube and the outer perforated tube are both 10% to 20%, and the diameter of each hole is 2 to 5 mm.

[0013] As a further preference, the aspect ratio of the low-resistance rectifying silencer is 1.2-3.

[0014] As a further preference, the sound-absorbing material is polyurethane sound-absorbing cotton.

[0015] As a further preference, a support plate is provided between the outer perforated tube and the inner perforated tube for support.

[0016] As a further preference, the inlet cannula, the outer perforated tube, the outlet cannula, the inner perforated tube, the rectifier tube and the support plate are all made of stainless steel plates.

[0017] In general, the above technical solutions conceived by the present invention have the following technical advantages compared with the existing technology:

[0018] 1. The present invention effectively improves sound attenuation by providing an internal rectifier cavity and external sound-absorbing materials. Furthermore, the overall device forms an expansion cavity. The tapered, expanding inlet cannula and the rectifier tube act as a diversion mechanism, mitigating the high resistance generated by the sudden change in area when liquid flows from the external capillary tube into the expansion cavity, significantly reducing resistance losses. This effectively improves sound attenuation while maintaining low resistance performance. The device's simple structure facilitates fabrication, making it suitable for widespread adoption in fields such as pipeline silencing and noise reduction.

[0019] 2. After entering the silencer, the liquid is split into two parts. One part of the sound carried by the fluid enters the sound-absorbing material area through the outer perforated tube. The sound energy is converted into heat energy through energy conversion, consuming part of the sound. At the same time, the sound resonates in the 1 / 4 resonance cavity to achieve silencer. The other part of the sound carried by the fluid enters the rectifier cavity through the inner perforated tube. The sound passes through the perforated wall and consumes part of the sound energy, thereby achieving an improvement in the overall frequency band silencer.

[0020] 3. The longer the intubation length, the lower the peak frequency in the transmission loss curve and the smaller the resistance loss of the muffler. The effective length of the inlet intubation is designed to be 0.5L, and the effective length of the outlet intubation is designed to be 0.25L. The specific inlet intubation length is 1 / 2 of the expansion chamber length, which can eliminate the odd multiples of half the wavelength passing through the frequency, and the outlet intubation length is 1 / 4 of the expansion chamber length, which can eliminate the even multiples of half the wavelength passing through the frequency, reducing the frequency limitation of the expansion chamber.

[0021] 4. The larger the angle of the tapered inlet pipe, the lower the peak frequency in the transmission loss curve, but the overall sound attenuation decreases. When the tapered angle is less than a certain angle, the resistance loss caused by the sudden change of the cross section can be effectively reduced. The diffusion angle and contraction angle of the inlet and outlet pipes are designed accordingly.

[0022] 5. The larger the expansion ratio of the tapered tube, the better the noise reduction performance, but the greater the resistance loss. Balancing the resistance and noise reduction, the expansion ratio of the low-resistance rectifier muffler is designed accordingly to maximize the noise reduction while meeting the space size requirements.

[0023] 6. Reducing the perforation diameter or increasing the perforation ratio of the perforated tube can improve the muffler's performance at medium and high frequencies. The smaller the perforation diameter or the lower the perforation ratio, the lower the pressure loss of the muffler. To balance the muffler's performance and resistance, the perforation ratio of the inner and outer perforated tubes is designed to be 10% to 20%, and the diameter of each hole is 2 to 5 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a radial cross-sectional view of a low-resistance rectifying muffler according to an embodiment of the present invention;

[0025] Figure 2 This is an axial cross-sectional view of a low-resistance rectifying muffler according to an embodiment of the present invention;

[0026] Figure 3 This is the transmission loss curve of the low-resistance rectifying silencer according to the embodiment of the present invention.

[0027] In all drawings, the same reference numerals are used to denote the same elements or structures, where: 1 - inlet cannula, 2 - outer perforated tube, 3 - rectifier tube, 4 - sound absorption area, 5 - support plate, 6 - outlet cannula, 7 - inner perforated tube, 8 - outer tube. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0029] The embodiment of the present invention provides a low-resistance rectifier type silencer, such as Figure 1 and Figure 2 As shown, it includes an outer tube 8, an inlet cannula 1, an outer perforated tube 2, an outlet cannula 6, an inner perforated tube 7 and a rectifier tube 3, wherein:

[0030] The inlet cannula 1, the outer perforated tube 2, and the outlet cannula 6 are connected in sequence and are all located within the outer tube 8. The interior of the outer tube 8 is an expansion chamber. One side of the inlet cannula 1 is directly connected to the external cooling water pipeline, and the other side is connected to the outer perforated tube 2. The outer side of the whole formed by the inlet cannula 1, the outer perforated tube 2, and the outlet cannula 6 is filled with sound-absorbing material between the outer side and the outer tube 8 to form a sound-absorbing area 4.

[0031] The inlet cannula 1 is a tapered gradually expanding tube, and the outlet cannula 6 is a tapered gradually converging tube. The tapered tube structure can effectively reduce flow resistance loss;

[0032] The rectifier tube 3 is a tapered, gradually expanding tube with a closed inlet. It is located at the center of the expansion chamber axis and close to the inlet side, which can reduce the flow resistance inside the muffler. The inner perforated tube 7 is connected to the rectifier tube 3, and the inner perforated tube 7 and the rectifier tube 3 form a rectifier cavity.

[0033] The inner perforated tube 7 and the outer perforated tube 2 are both provided with a plurality of holes. The inner perforated tube 7 and the outer perforated tube 2 are coaxially arranged. Preferably, the inner perforated tube 7 and the outer perforated tube 2 have the same length. A support plate 5 is provided between the outer perforated tube 2 and the inner perforated tube 7 for support.

[0034] Furthermore, both the inlet cannula 1 and the outlet cannula 6 have rigid walls; the inlet cannula 1 forms a quarter-resonance cavity with the expansion cavity wall (corresponding to the region of the outer tube 8, where the corresponding region is within the same axial range of the device), while the outlet cannula 6 forms a quarter-resonance cavity with the expansion cavity wall (corresponding to the region of the outer tube 8). Furthermore, when the resonant frequency is equal to the muffler's own pass frequency, the muffler's sound attenuation can be improved.

[0035] Furthermore, the diffusion angle of the inlet cannula 1 is 10° to 14°, and the contraction angle of the outlet cannula 6 is 10° to 40°.

[0036] Furthermore, the ratio of the area at the outlet of the inlet cannula 1 to the area at the inlet is 2:1 to 6:1, and the ratio of the area at the inlet of the outlet cannula 6 to the area at the outlet is 2:1 to 6:1.

[0037] Furthermore, the effective length of the inlet cannula 1 is 0.5L, and the effective length of the outlet cannula 6 is 0.25L, where L is the effective length of the outer tube 8, and the effective length refers to the length in the axial direction of the device.

[0038] Furthermore, the aspect ratio of the device (i.e., the expansion chamber) is 1.2 to 3. The larger the aspect ratio, the better the sound attenuation performance, but the greater the resistance loss. The aspect ratio of the device is designed to balance the sound attenuation performance and the resistance loss.

[0039] Furthermore, the perforation ratio (the percentage of holes on the tube wall surface to the entire tube wall surface area) of the inner perforated tube 7 and the outer perforated tube 2 is 10% to 20%, and the diameter of each hole is 2 to 5 mm.

[0040] Furthermore, the sound-absorbing material is polyurethane sound-absorbing cotton.

[0041] Furthermore, the inlet cannula 1 , the outer perforated tube 2 , the outlet cannula 6 , the inner perforated tube 7 , the rectifier tube 3 and the support plate 5 are all made of stainless steel plates.

[0042] The following are specific embodiments:

[0043] In the low-resistance rectifying silencer, the expansion ratio of the inlet cannula 1 and the outlet cannula 6 is 4, the diffusion angle of the inlet cannula 1 is 12.5°, and the contraction angle of the outlet cannula 6 is 24.5°; the effective length of the inlet cannula 1 is 0.5L, and the effective length of the outlet cannula 6 is 0.25L; the aspect ratio of the expansion cavity is 1.3; the wall thickness of the inner perforated tube 7 and the outer perforated tube 2 is 4mm, the perforation rate is 15%, and the aperture of each hole is 5mm.

[0044] For this low-resistance rectifying silencer, when the inlet flow velocity is 4.07 m / s, the calculated inlet pressure is 9452.5 Pa, the outlet pressure is 8309.9 Pa, and the pressure loss is 1142.6 Pa. Figure 3 As shown, this low-resistance rectifier muffler essentially eliminates the pass-through frequency within the 5-3000Hz frequency range. The sound insulation falls below 8dB only in the 1400-1500Hz and 2700-2800Hz bands, with the lowest sound insulation being 5.6dB, occurring around 2800Hz. The sound insulation in the remaining frequency bands is above 8dB. The average sound insulation within the 50-3000Hz frequency range is 15.8dB, demonstrating good noise reduction performance.

[0045] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A low-resistance rectifier silencer, characterized in that: It comprises an outer tube (8), an inlet cannula (1), an outer perforated tube (2), an outlet cannula (6), an inner perforated tube (7) and a rectifier tube (3), wherein: The inlet cannula (1), the outer perforated tube (2), and the outlet cannula (6) are connected in sequence and are all located inside the outer tube (8); the outer side of the whole formed by the inlet cannula (1), the outer perforated tube (2), and the outlet cannula (6) and the outer tube (8) are filled with sound-absorbing material; the inlet cannula (1) is a tapered gradually expanding tube, and the outlet cannula (6) is a tapered gradually converging tube; The rectifier tube (3) is a tapered, gradually expanding tube with a closed inlet, which is located at the center of the device axis and close to the inlet side of the device; the inner perforated tube (7) is connected to the rectifier tube (3), and the inner perforated tube (7) and the rectifier tube (3) form a rectifier cavity; the inner perforated tube (7) and the outer perforated tube (2) are both provided with a plurality of holes, and the inner perforated tube (7) and the outer perforated tube (2) are coaxially arranged; The effective length of the inlet cannula (1) is 0.5L, and the effective length of the outlet cannula (6) is 0.25L, where L is the effective length of the outer tube (8), and the effective length refers to the length in the axial direction of the device; The inlet cannula (1) and the outlet cannula (6) both have rigid tube walls; the corresponding areas of the inlet cannula (1) and the outer tube (8) form a 1 / 4 resonance cavity, and the corresponding areas of the outlet cannula (6) and the outer tube (8) form a 1 / 4 resonance cavity.

2. The low-resistance rectifying type silencer according to claim 1, characterized in that: The diffusion angle of the inlet cannula (1) is 10° to 14°, and the contraction angle of the outlet cannula (6) is 10° to 40°.

3. The low-resistance rectifying type muffler according to claim 1, characterized in that: The ratio of the area at the outlet of the inlet cannula (1) to the area at the inlet is 2:1 to 6:1, and the ratio of the area at the inlet of the outlet cannula (6) to the area at the outlet is 2:1 to 6:

1.

4. The low-resistance rectifying type muffler according to claim 1, characterized in that: The perforation rates of the inner perforated tube (7) and the outer perforated tube (2) are both 10% to 20%, and the diameter of each hole is 2 to 5 mm.

5. The low-resistance rectifying type silencer according to claim 1, characterized in that: The low-resistance rectifying type silencer has an aspect ratio of 1.2 to 3.

6. The low-resistance rectifying type silencer according to claim 1, characterized in that: The sound absorbing material is polyurethane sound absorbing cotton.

7. The low-resistance rectifying muffler according to any one of claims 1 to 6, characterized in that: A support plate (5) is provided between the outer perforated tube (2) and the inner perforated tube (7) for support.

8. The low-resistance rectifying type muffler according to claim 7, characterized in that: The inlet cannula (1), the outer perforated tube (2), the outlet cannula (6), the inner perforated tube (7), the rectifier tube (3) and the support plate (5) are all made of stainless steel plates.

Images