A ventilation pipe noise reduction muffler

Abstract

A ventilation duct noise reduction silencer relates to the technical field of pipeline noise reduction. The noise reduction silencer is connected to a cooling tower exhaust duct and comprises a rectangular inner tube. The rectangular inner tube is installed on the air outlet end of the cooling tower exhaust duct by multiple bolts. A plurality of silencer rings are provided on the inner circumference of the rectangular inner tube. A silencer portion is provided between two adjacent silencer rings. The silencer portion is arranged horizontally or vertically. A plurality of circles of sound insulation portions are provided on the outer circumference of the rectangular inner tube. The silencer rings and the silencer portions are combined to reduce the noise of the rectangular inner tube, mainly by reflecting the noise and repeatedly reflecting it in the cavity, thereby significantly improving the noise reduction effect. In addition, the sound insulation portion is provided to further hinder the noise from propagating outward from the rectangular inner tube, thereby improving the noise reduction effect, and there will be no problems of slag falling and failure.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline noise reduction, and in particular to a ventilation pipe noise reduction muffler. Background Art

[0002] Aerodynamic noise pollution is a common problem at the exhaust vents of industrial ventilation systems, such as cooling towers and air circulation systems. This noise primarily originates from broadband turbulent noise caused by airflow disturbances, as well as medium- and low-frequency rotational noise generated by impeller rotation. Its acoustic characteristics are characterized by strong penetration and long-range propagation. Existing noise reduction measures for ventilation systems primarily employ a combination of reactive mufflers and resistive sound-absorbing materials, such as the application of sound-absorbing materials like silencing felt on the exterior of ventilation ducts. However, actual applications have shown that this traditional noise reduction solution has significant technical defects: first, the airflow impedance caused by the resistive structure will reduce the system air volume by 15%-30%, directly affecting the heat exchange efficiency of equipment such as cooling towers; second, the composite propagation characteristics of broadband noise make it difficult for a single noise reduction method to cover the entire frequency band of noise. Actual measured data show that when the exhaust speed is lower than 3m / s, the noise reduction efficiency decays by more than 40%; third, sound-absorbing materials are prone to fiber shedding and aging degradation when exposed to a humid and hot environment for a long time. Literature research shows that the noise reduction coefficient (NRC) value of the sound-absorbing felt decreases by an average of 0.6 after two years of use, seriously weakening the long-term noise reduction effect.

[0003] What is more noteworthy is that the existing technology has not fully considered the coordinated optimization of aerodynamics and acoustic characteristics. The energy peak of turbulent noise in ventilation ducts is concentrated in the range of 50Hz-2000Hz, while traditional resistive silencers are only effective for specific resonant frequencies. The sound absorption efficiency of resistive materials in the medium and low frequency bands is insufficient, resulting in limited overall noise reduction effects. At the same time, the secondary aerodynamic noise problem caused by the increased surface roughness of the material further offsets part of the noise reduction benefits. This technical contradiction makes it difficult for existing solutions to achieve continuous and effective noise control while ensuring the system air volume, which restricts the application of equipment in sensitive places such as medical areas and residential areas. Summary of the Invention

[0004] The present invention provides a ventilation pipe noise reduction muffler to solve the above-mentioned shortcomings of the prior art, that is, the problem of poor ventilation pipe noise reduction effect, and has strong practicality.

[0005] In order to achieve the purpose of the present invention, the following technologies are proposed:

[0006] A ventilation duct noise reduction silencer is connected to a cooling tower exhaust duct, comprising a rectangular inner tube, which is installed on the air outlet end of the cooling tower exhaust duct by means of a plurality of bolts. A plurality of silencer rings are provided on the inner circumference of the rectangular inner tube, and a silencer portion is provided between two adjacent silencer rings. The silencer portion is arranged horizontally or vertically, and a plurality of circles of sound insulation portions are provided on the outer circumference of the rectangular inner tube. The silencer rings and the silencer portion are combined to silence the rectangular inner tube, mainly by reflecting the noise and repeatedly reflecting it in the cavity, thereby reducing the energy required for noise propagation, thereby significantly improving the noise reduction effect. In addition, the sound insulation portion is provided to further hinder the noise from propagating outward from the rectangular inner tube, thereby improving the noise reduction effect, and there will be no problems of slag falling and failure.

[0007] Furthermore, the silencer ring includes an inner rectangular ring, a conical frame plate is formed at the rear end of the inner rectangular ring, the outer end of the conical frame plate expands outward, and a front frame plate is formed at the front end of the inner rectangular ring. The front frame plate, the inner rectangular ring and the conical frame plate together form an annular cavity, and a plurality of partitions are welded in the annular cavity. Two adjacent partitions, the inner rectangular ring, the front frame plate and the conical frame plate form a silencer cavity. A silencer fiber sheet is provided in the open end of the silencer cavity, and the outer periphery of the conical frame plate and the outer periphery of the front frame plate are fixed to the inner periphery of the rectangular inner tube by welding. One end of the silencer cavity is connected with a strip hole, and the strip hole is located on the conical frame plate, wherein the opening size of the conical frame plate is larger One end faces the air inlet end of the rectangular inner tube. When airflow enters the rectangular inner tube, the presence of the tapered frame plate reduces the cross-sectional area through which the airflow can pass, leaving a larger cross-sectional area at the rear end of the front frame plate. This causes reflection and phase interference during noise propagation, with some sound waves returning to the direction of the sound source. During this reflection process, the returning sound waves and the sound waves generated by the sound source overlap, resulting in overlapping troughs and peaks, thereby weakening the propagation of the sound waves. The tapered structure of the tapered frame plate not only provides a gradual structure for the passage of air but also facilitates the reflection of sound waves, thereby enhancing the noise reduction effect. To further enhance the effect, multiple silencer rings are arranged at intervals. This creates multiple expansion and contraction chambers when the airflow is discharged, further reducing noise transmission. Furthermore, since the silencer rings are arranged around the circumference of the rectangular inner tube, they prevent noise from propagating outward while also preventing interference with the airflow. In addition, when the noise propagates forward, it will form sound wave diffraction through the strip holes, and considering that the smaller the size of the strip holes, the less energy is consumed during diffraction, the width and depth of the strip holes are set to between 0.1mm and 0.5mm. The setting of the strip holes increases the amount of noise entering during noise diffraction, and the noise entering the strip holes and diffracting will form multiple reflections and phase interference in the silencer cavity, thereby further reducing the energy of the noise propagating outward. In addition, the noise is further reduced by the silencer fiber sheets that are set. In summary, the silencer ring can not only achieve the purpose of noise reduction, but also avoid causing major obstacles to the exhaust effect.

[0008] Furthermore, in order to supplement the silencing of the parts of the two adjacent silencer rings and reduce the noise inside the airflow, thereby reducing the noise in the area directly opposite the air outlet of the rectangular inner tube, a silencer is also provided. The silencer includes a plurality of groups of vertical members arranged in pairs, and the two ends of the vertical members in the length direction are respectively welded to the inner wall of the rectangular inner tube. The length direction of the vertical members is perpendicular to the length direction of the rectangular inner tube. The vertical members are hollow structures, and the inner walls of the vertical members are formed with grooves. The grooves on each group of vertical members are arranged oppositely, and the outer sides of the vertical members are relatively close to each other. A convex shell is welded to the wall, and the convex shell is arranged opposite to the groove. When the noise propagates, it propagates outward from between two adjacent vertical pieces, and first passes through the cavity formed by the vertical pieces and the rectangular inner tube. Due to the presence of the groove, this cavity will form a structure with a small cavity at the air inlet end, a large cavity in the middle, and a small space at the air outlet end. This structure can form multiple reflections and phase interference on the noise, and is combined with the above-mentioned silencer ring to further achieve the effect of noise reduction. Moreover, this structure is located inside the rectangular inner tube, thereby reducing the noise reduction effect of the area directly facing the outlet of the rectangular inner tube.

[0009] Furthermore, the groove has an isosceles trapezoidal structure. This structural design not only helps to reflect noise, but also enables the airflow to flow smoothly to avoid affecting the flow of air.

[0010] Furthermore, the front end of the cross section of the vertical member is an isosceles trapezoidal structure, which can increase and then decrease the space at the air inlet end, ensuring smooth passage of airflow while reflecting noise through the inclined surface thereon.

[0011] Furthermore, the rear end of the cross section of the vertical member is in an arc-shaped structure, so as to enhance the reflection and phase interference of noise through the arc surface, thereby further enhancing the noise reduction effect.

[0012] Furthermore, from the above description, it can be seen that since the groove is only provided on one side of the vertical member, the noise reduction effect between the two adjacent groups of vertical members is weak, so the cross-section of the convex shell is an isosceles trapezoidal structure, and micropores are respectively provided on the two inclined surfaces of the convex shell. A middle partition is welded inside the convex shell, and the two ends of the convex shell in the length direction are closed by welding an end plate. The middle partition is welded to the outer wall of the vertical member, and the middle partition divides the cavity of the convex shell with an isosceles trapezoidal structure into two parts. Through the setting of the convex shell, a structure with a larger air inlet end space, a smaller middle position space, and a larger air outlet end space can be formed between the two adjacent vertical members, thereby further improving the noise reduction effect through this structure. In addition, the inclined surface on the convex shell can reflect and phase interfere with the noise, and when the noise is diffracted through the micropores, its propagation energy will be reduced, and since the noise enters a closed cavity, multiple reflections can prevent the further propagation of the noise.

[0013] Furthermore, although a certain noise reduction effect can be achieved through the silencer ring and the silencer part, some noise will still diffuse outward through the rectangular inner tube. In order to further improve the noise reduction and sound insulation effect, a sound insulation part is specially set up. The sound insulation part includes multiple sound insulation units, and the sound insulation units are ring-shaped on the rectangular inner tube.

[0014] The sound insulation unit includes four outer tubes, the inner walls of which are affixed with sound insulation felt. The outer tubes have a cavity inside, and a circular hole is opened at one end of the outer tubes. An inner tube is arranged in the cavity of the outer tubes, and the inner tube has a liquid-filled cavity. The ends of the inner tubes in the longitudinal direction are closed, and an inner plate is formed in a sealing manner at the other end of the inner tube in the longitudinal direction. The inner plate is sunk into the inner tube, and an injection tube is formed on the inner plate. The outer end of the injection tube is connected to a closure cap by a thread, and the closure cap faces the circular hole. The above-mentioned outer tubes are made of iron or aluminum alloy. They are mainly used to protect the sound insulation components inside them to increase service life and also facilitate the fixing of them and the sound insulation components inside them to the rectangular inner tube. The inner tube provided therein can reduce the transmission of isolated noise by filling it with liquid, such as water, and the injection tube on it facilitates the injection operation of liquid. In addition, by filling the inner tube with liquid, such as water, the noise transmission can be reduced while absorbing the noise energy. After absorbing the noise energy, it also helps to dissipate the heat generated by the noise transmission.

[0015] A pair of triangular plates are formed at both ends of the outer wall of the outer pipe fitting, and the inner wall of the triangular plate is a slope. The ends of the two adjacent outer pipe fittings are provided with L-shaped plates, and the outer ends of the L-shaped plates are respectively bent with fixed end plates. The fixed end plates are fixed to the outer pipe fittings by screws. A rectangular hole is opened on the fixed end plate, and the triangular plate is passed through the rectangular hole, and the inner wall of the outer end of the rectangular hole acts on the slope of the triangular plate. When connected, the L-shaped plate and the rectangular hole on it can act on the slope of the triangular plate, so that the sound insulation felt of each outer pipe fitting and its inner wall can be tightly attached to the rectangular outer pipe, thereby improving the noise reduction and sound insulation effect.

[0016] The outer wall of the outer pipe is formed with a plurality of isosceles trapezoidal grooves along its length direction, and a notch is provided at the outer end of the isosceles trapezoidal groove, and the notch faces the front end of the outer pipe, and the opening size of the inner end of the isosceles trapezoidal groove is larger than the opening size of its outer end. The outer wall of the outer pipe is formed with a plurality of connecting plates along its length direction, and a clamping plate with an isosceles trapezoidal structure is formed at the other end of the connecting plate. When two adjacent sound insulation units are connected and fixed, the clamping plate on the sound insulation unit at the front end is clamped in the isosceles trapezoidal groove, and the connecting plate is clamped in the notch. The isosceles trapezoidal groove and the clamping plate are provided to facilitate the connection operation between the two adjacent sound insulation units.

[0017] Furthermore, the inner wall of the outer tube is provided with a plurality of inner strips, the length direction of the inner strips is parallel to the length direction of the outer tube, the inner wall of the inner strips is tightly attached to the outer wall of the inner tube, and fillers such as foam materials are filled between the inner strips and the inner tube. The inner strips improve the deformation resistance of the outer tube to a certain extent, and also serve as a buffer and energy absorption component to prevent damage to the inner tube when it is hit.

[0018] Furthermore, an inner plug-in column is provided on the inner side of the closing cover, and the inner plug-in column is inserted into the liquid injection tube. The provision of the inner plug-in column improves the sealing effect of the closing cover.

[0019] Furthermore, a plurality of inclined plates are provided in the cavity of the inner tube, and a gap exists between one end of the inclined plate and the inner plate. The provision of the inclined plates can improve the internal strength of the inner tube.

[0020] Furthermore, a pair of air hoods are provided on the inner plate, the air hoods are cylindrical in structure, and the outer ends of the air hoods extend out of the outer side of the inner plate, the inner ends of the air hoods are located on the inner side of the inner plate, the outer ends of the air hoods are formed with a conical hole, the outer ends of the conical holes are small ends, a plurality of exhaust holes are provided on the peripheral side of the air hood, the exhaust holes are located on the inner side of the inner plate, the inner end of the air hood is provided with an inner hole, a plurality of guide strips are formed on the inner periphery of the air hood, a sealing disk is provided inside the air hood, the outer periphery of the sealing disk is clamped on the guide strips, a conical column is formed on the outer end of the sealing disk, the outer end of the conical column is small ends, when water is filled into the inner tube, the air hood facilitates the discharge of air in the inner tube, and when the water is full, the sealing disk can move upward with the buoyancy of the water, and insert the conical column into the conical hole to seal the air hood.

[0021] The advantages of the above technical solution are:

[0022] The present invention improves the noise reduction effect of the cooling tower exhaust port while having little influence on the exhaust flow rate;

[0023] The present invention further improves the noise reduction and sound insulation effects by arranging sound insulation facilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.

[0025] Figure 1 Shown is a three-dimensional structural diagram of a ventilation pipe noise reduction muffler.

[0026] Figure 2 A first-perspective stereoscopic structural diagram of the silencer is shown.

[0027] Figure 3 A second perspective stereoscopic structural diagram of the silencer ring is shown.

[0028] Figure 4It shows the three-dimensional structure of the silencer ring and the silencer part.

[0029] Figure 5 A perspective structural diagram of the muffler is shown.

[0030] Figure 6 A three-dimensional structural diagram of the convex hull is shown.

[0031] Figure 7 A three-dimensional structural diagram of the sound insulation part is shown.

[0032] Figure 8 Shown is a three-dimensional structural diagram of the outer pipe.

[0033] Figure 9 A three-dimensional structural diagram of the inner tube is shown.

[0034] Reference numerals:

[0035] Cooling tower exhaust pipe 1;

[0036] Silencer 2, inner rectangular ring 20, conical frame plate 21, strip hole 22, partition 23, silencer cavity 24, front frame plate 25;

[0037] The muffler 3, the vertical member 30, the groove 300, the convex shell 31, the micro hole 310, and the middle partition 311;

[0038] Sound insulation part 4, outer pipe 400, sound insulation felt 401, isosceles trapezoidal groove 402, notch 403, clamping plate 404, connecting plate 405, triangular plate 406, L-shaped plate 407, side reinforcement plate 408, fixed end plate 409, rectangular hole 410, inner strip 411, inner tube 412, inner plate 413, inclined plate 414, liquid injection tube 415, closing cover 416, inner plug 417, breathable cover 418, inner hole 419, exhaust hole 420, guide strip 421, sealing plate 422, tapered column 423, tapered hole 424;

[0039] Rectangular inner tube 5. DETAILED DESCRIPTION

[0040] like Figure 1 As shown, a ventilation duct noise reduction silencer is connected to the cooling tower exhaust duct 1, including a rectangular inner tube 5, which is installed on the air outlet end of the cooling tower exhaust duct 1 by multiple bolts. A plurality of silencer rings 2 are provided on the inner circumference of the rectangular inner tube 5, and a silencer part 3 is provided between two adjacent silencer rings 2. The silencer part 3 is arranged horizontally or vertically, and a plurality of circles of sound insulation parts 4 are provided on the outer circumference of the rectangular inner tube 5.

[0041] like Figure 2 and Figure 3As shown, the silencer 2 includes an inner rectangular ring 20, a conical frame plate 21 is formed at the rear end of the inner rectangular ring 20, the outer end of the conical frame plate 21 expands outward, and a front frame plate 25 is formed at the front end of the inner rectangular ring 20. The front frame plate 25, the inner rectangular ring 20 and the conical frame plate 21 together form an annular cavity, and a plurality of partitions 23 are welded in the annular cavity. Two adjacent partitions 23, the inner rectangular ring 20, the front frame plate 25 and the conical frame plate 21 form a silencer cavity 24, and a silencer fiber sheet is provided in the open end of the silencer cavity 24, and the outer periphery of the conical frame plate 21 and the outer periphery of the front frame plate 25 are fixed to the inner periphery of the rectangular inner tube 5 by welding. One end of the silencer cavity 24 is connected to a strip hole 22, and the strip hole 22 is located on the conical frame plate 21. The internal silencer component of the rectangular inner tube formed by the above structure forms a plurality of cavities in the rectangular inner tube 5, the air inlet end of which gradually decreases and the air outlet end of which becomes larger. This cavity structure reduces noise through the reflection and phase interference of sound waves, and reduces the propagation energy of noise through the diffraction of sound waves by the strip holes 22 and the reflection of each silencer cavity 24, thereby improving the noise reduction effect.

[0042] like Figures 4 to 6 As shown, the muffler 3 includes a plurality of groups of vertical members 30 arranged in pairs, the front end of the cross section of the vertical member 30 is an isosceles trapezoidal structure, and the rear end of the cross section of the vertical member 30 is an arc-shaped structure. The two ends of the vertical member 30 in the length direction are respectively welded to the inner wall of the rectangular inner tube 5, and the length direction of the vertical member 30 is perpendicular to the length direction of the rectangular inner tube 5. The vertical member 30 is a hollow structure, and a groove 300 is formed on the inner wall of the vertical member 30. The groove 300 is an isosceles trapezoidal structure. The grooves 300 on each group of vertical members 30 are arranged opposite to each other, and a convex shell 31 is welded to the outer wall of the vertical member 30, and the convex shell 31 is arranged opposite to the groove 300. The cross-section of the convex shell 31 is an isosceles trapezoidal structure, and micropores 310 are respectively opened on the two inclined surfaces of the convex shell 31. A middle partition 311 is welded inside the convex shell 31, and the two ends of the convex shell 31 in the longitudinal direction are closed by welding an end plate. The middle partition 311 is welded to the outer wall of the vertical member 30. The middle partition 311 divides the cavity of the isosceles trapezoidal structure of the convex shell 31 into two parts.

[0043] In summary, the muffler 3 is arranged to reduce and attenuate the noise in each large cavity formed by the silencer ring 2, and is intended to reduce the noise reduction effect in the area directly opposite the air outlet of the rectangular inner tube 5. The noise reduction is achieved by forming a plurality of noise reduction structures, wherein the air inlet space formed by each pair of vertical members 30 is relatively large, then gradually shrinks, and then the air outlet space is enlarged by the groove 300, then reduced again, and finally enlarged. In addition, the noise reduction effect is enhanced by combining the structure formed by the convex shell 31, in which the air inlet space is large, the middle space is small, and the air outlet space is small. In addition, the noise reduction effect is enhanced by combining the above structures, and the noise reduction effect is enhanced by combining the noise reduction method of consuming sound wave energy through sound wave diffraction and multiple reflections in a closed space.

[0044] like Figure 1 As shown, the sound insulation part 4 includes a plurality of sound insulation units, and the sound insulation units are sleeved on the rectangular inner tube 5.

[0045] like Figures 7 to 9 As shown, the sound insulation unit includes four outer pipes 400, the inner wall of the outer pipe 400 is pasted with a sound insulation felt 401, the inner part of the outer pipe 400 has a cavity, and one end of the outer pipe 400 is provided with a circular hole, the cavity of the outer pipe 400 is provided with an inner pipe 412, the inner wall of the outer pipe 400 is provided with a plurality of inner strips 411, the length direction of the inner strips 411 is parallel to the length direction of the outer pipe 400, the inner wall of the inner strips 411 is closely attached to the outer wall of the inner pipe 412, the inner pipe 412 has a liquid-filled cavity, and the cavity of the inner pipe 412 There are multiple inclined plates 414, and there is a gap between one end of the inclined plate 414 and the inner plate 413. The end of the inner tube 412 in the length direction is closed, and the other end of the inner tube 412 in the length direction is sealed with the inner plate 413. The inner plate 413 is sunk inside the inner tube 412, and an injection tube 415 is formed on the inner plate 413. The outer end of the injection tube 415 is connected to a closing cover 416 through a thread. The closing cover 416 is opposite to the circular hole. An inner column 417 is provided on the inner side of the closing cover 416, and the inner column 417 is inserted into the injection tube 415.

[0046] A pair of air hoods 418 are provided on the inner plate 413. The air hoods 418 are cylindrical in structure, and the outer ends of the air hoods 418 extend out of the outer side of the inner plate 413, and the inner ends of the air hoods 418 are located on the inner side of the inner plate 413. The outer ends of the air hoods 418 are formed with tapered holes 424, and the outer ends of the tapered holes 424 are small ends. A plurality of exhaust holes 420 are provided on the peripheral sides of the air hoods 418, and the exhaust holes 420 are located on the inner side of the inner plate 413. An inner hole 419 is provided on the inner end of the air hoods 418. A plurality of guide bars 421 are formed on the inner periphery of the air hoods 418. A sealing disk 422 is provided in the air hood 418, and the outer periphery of the sealing disk 422 is clamped on the guide bars 421. A conical column 423 is formed on the outer end of the sealing disk 422, and the outer end of the conical column 423 is a small end.

[0047] A pair of triangular plates 406 are formed at both ends of the outer wall of the outer tube fitting 400. The inner wall of the triangular plate 406 is a slope with an inclination angle of 45 degrees. An L-shaped plate 407 is provided at the end of the two adjacent outer tube fittings 400. Side reinforcing plates 408 are welded on both sides of the L-shaped plate 407 to prevent the L-shaped plate 407 from deformation. The outer ends of the L-shaped plate 407 are respectively bent with fixed end plates 409, which are fixed to the outer tube fitting 400 by screws. A rectangular hole 410 is opened on the fixed end plate 409, and the triangular plate 406 is inserted into the rectangular hole 410, and the inner wall of the outer end of the rectangular hole 410 acts on the slope of the triangular plate 406.

[0048] The outer wall of the outer tube 400 is formed with a plurality of isosceles trapezoidal grooves 402 along its length direction, and a notch 403 is provided at the outer end of the isosceles trapezoidal groove 402, and the notch 403 faces the front end of the outer tube 400. The opening size of the inner end of the isosceles trapezoidal groove 402 is larger than the opening size of its outer end. The outer wall of the outer tube 400 is formed with a plurality of connecting plates 405 along its length direction, and a clamping plate 404 with an isosceles trapezoidal structure is formed at the other end of the connecting plate 405. When two adjacent sound insulation units are connected and fixed, the clamping plate 404 on the sound insulation unit at the front end is clamped in the isosceles trapezoidal groove 402, and the connecting plate 405 is clamped in the notch 403.

[0049] In this embodiment, when water is injected into the inner tube 412, the water pipe can be connected to the injection pipe 415, and then water is injected into the inner tube 412. During the injection process, air enters the breathable cover 418 through the exhaust hole 420 and is finally discharged from the tapered hole 424. As water continues to be injected, the sealing disk 422 will be pushed upward by the buoyancy and pressure of the water, and finally the cone 423 is inserted into the tapered hole 424. Then the closing cover 416 is screwed onto the injection pipe 415. Next, the water-filled outer tube 400 and the soundproofing felt 401 thereon are placed snugly against the rectangular inner tube 5, so that every four outer tubes 400 fit over the rectangular inner tube 5. L-shaped plates 407 are then secured to two adjacent outer tubes 400, with the outer ends of the rectangular holes 410 acting on the triangular plates 406. Once secured, the retaining plates 404 of the outer tubes 400 on the adjacent soundproofing units are secured within the isosceles trapezoidal grooves 402, thus completing the securing of the entire soundproofing unit 4. The soundproofing process utilizes the principle that water hinders the propagation of sound waves to enhance the noise isolation effect.

[0050] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It is apparent that various modifications and variations may be made by those skilled in the art without departing from the spirit and scope of the present invention. Thus, the present invention is intended to encompass such modifications and variations as long as they fall within the scope of the claims and their equivalents.

Claims

1. A ventilation pipe noise reduction muffler connected to a cooling tower exhaust pipe (1), characterized in that: It comprises a rectangular inner tube (5), which is mounted on the air outlet end of the cooling tower exhaust pipe (1) via a plurality of bolts; A plurality of silencer rings (2) are provided on the inner circumference of the rectangular inner tube (5), a silencer portion (3) is provided between two adjacent silencer rings (2), the silencer portion (3) is arranged horizontally or vertically, and a plurality of sound insulation portions (4) are provided on the outer circumference of the rectangular inner tube (5); The silencer ring (2) includes an inner rectangular ring (20), a conical frame plate (21) is formed at the rear end of the inner rectangular ring (20), the outer end of the conical frame plate (21) expands outward, and a front frame plate (25) is formed at the front end of the inner rectangular ring (20), the front frame plate (25), the inner rectangular ring (20) and the conical frame plate (21) are surrounded to form an annular cavity, a plurality of partitions (23) are welded in the annular cavity, two adjacent partitions (23), the inner rectangular ring (20), the front frame plate (25) and the conical frame plate (21) form a silencer cavity (24), a silencer fiber sheet is provided in the open end of the silencer cavity (24), and the outer periphery of the conical frame plate (21) and the outer periphery of the front frame plate (25) are fixed to the inner periphery of the rectangular inner tube (5) by welding, and one end of the silencer cavity (24) is connected to a strip hole (22), and the strip hole (22) is located on the conical frame plate (21); The muffler (3) includes a plurality of groups of vertical members (30) arranged in pairs, the rear end of the cross section of the vertical member (30) is in an arc-shaped structure, the two ends of the vertical member (30) in the length direction are respectively welded to the inner wall of the rectangular inner tube (5), the length direction of the vertical member (30) is perpendicular to the length direction of the rectangular inner tube (5), the vertical member (30) is a hollow structure, the inner wall of the vertical member (30) is formed with a groove (300), the grooves (300) on each group of vertical members (30) are arranged opposite to each other, and the outer wall of the vertical member (30) is welded with a convex shell (31), and the convex shell (31) is arranged opposite to the groove (300); The groove (300) has an isosceles trapezoidal structure; The front end of the cross section of the vertical member (30) is an isosceles trapezoidal structure; The cross section of the convex shell (31) is an isosceles trapezoidal structure, and micropores (310) are respectively opened on the two inclined surfaces of the convex shell (31). A middle partition (311) is welded inside the convex shell (31), and both ends of the convex shell (31) in the longitudinal direction are closed by welding an end plate. The middle partition (311) is welded to the outer wall of the vertical member (30), and the middle partition (311) divides the cavity of the convex shell (31) in the isosceles trapezoidal structure into two parts. The sound insulation part (4) includes a plurality of sound insulation units, and the sound insulation units are sleeved on the rectangular inner tube (5); The sound insulation unit includes four outer tubes (400), the inner walls of the outer tubes (400) are pasted with sound insulation felt (401), the outer tubes (400) have a cavity inside, and a circular hole is opened on one end of the outer tubes (400), an inner tube (412) is provided in the cavity of the outer tubes (400), the inner tubes (412) have a liquid-filled cavity, the ends of the inner tubes (412) in the longitudinal direction are closed, and the other end of the inner tubes (412) in the longitudinal direction is sealed with an inner plate (413), the inner plate (413) is sunk inside the inner tubes (412), an injection tube (415) is formed on the inner plate (413), the outer end of the injection tube (415) is connected to a closing cap (416) by a thread, and the closing cap (416) is directly opposite to the circular hole; A pair of triangular plates (406) are formed at both ends of the outer wall of the outer tube (400), and the inner walls of the triangular plates (406) are inclined surfaces. L-shaped plates (407) are provided at the ends of the two adjacent outer tubes (400), and fixed end plates (409) are bent at the outer ends of the L-shaped plates (407). The fixed end plates (409) are fixed to the outer tube (400) by screws. A rectangular hole (410) is provided on the fixed end plates (409), and the triangular plates (406) are inserted into the rectangular holes (410), and the inner walls of the outer ends of the rectangular holes (410) act on the inclined surfaces of the triangular plates (406). The outer wall of the outer tube (400) is formed with a plurality of isosceles trapezoidal grooves (402) along its length direction, the outer ends of the isosceles trapezoidal grooves (402) are provided with notches (403), and the notches (403) face the front end of the outer tube (400), the inner end opening size of the isosceles trapezoidal grooves (402) is larger than the outer end opening size, and the outer wall of the outer tube (400) is formed with a plurality of connecting plates (405) along its length direction, and the other ends of the connecting plates (405) are formed with a clamping plate (404) in the shape of an isosceles trapezoidal structure, and when two adjacent sound insulation units are connected and fixed, the clamping plate (404) on the sound insulation unit at the front end is clamped in the isosceles trapezoidal groove (402), and the connecting plate (405) is clamped in the notch (403).

2. The ventilation pipe noise reduction muffler according to claim 1, characterized in that: The inner wall of the outer tube (400) is provided with a plurality of inner strips (411), the length direction of the inner strips (411) is parallel to the length direction of the outer tube (400), and the inner wall of the inner strips (411) is closely attached to the outer wall of the inner tube (412); An inner plug-in column (417) is provided on the inner side of the closing cover (416), and the inner plug-in column (417) is inserted into the liquid injection tube (415); A plurality of inclined plates (414) are provided in the cavity of the inner tube (412), and a gap exists between one end of the inclined plate (414) and the inner plate (413).

3. The ventilation pipe noise reduction muffler according to claim 1, characterized in that: A pair of breathable covers (418) are provided on the inner plate (413), the breathable covers (418) are cylindrical in structure, and the outer end of the breathable covers (418) extends outward from the outer side of the inner plate (413), the inner end of the breathable covers (418) is located on the inner side of the inner plate (413), the outer end of the breathable covers (418) is formed with a tapered hole (424), the outer end of the tapered hole (424) is a small end, and a plurality of exhaust holes (424) are provided on the circumference of the breathable covers (418). 20), the exhaust hole (420) is located on the inner side of the inner plate (413), the inner end of the breathable cover (418) is provided with an inner hole (419), the inner periphery of the breathable cover (418) is formed with a plurality of guide bars (421), a sealing disk (422) is provided inside the breathable cover (418), the outer periphery of the sealing disk (422) is clamped on the guide bars (421), and a conical column (423) is formed on the outer end of the sealing disk (422), and the outer end of the conical column (423) is a small end.

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