RU2568799C1 - Multi-section noise suppressor - Google Patents

Multi-section noise suppressor Download PDF

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Publication number
RU2568799C1
RU2568799C1 RU2014125708/02A RU2014125708A RU2568799C1 RU 2568799 C1 RU2568799 C1 RU 2568799C1 RU 2014125708/02 A RU2014125708/02 A RU 2014125708/02A RU 2014125708 A RU2014125708 A RU 2014125708A RU 2568799 C1 RU2568799 C1 RU 2568799C1
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Russia
Prior art keywords
sound
absorbing
pipe
perforated
layer
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RU2014125708/02A
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Russian (ru)
Inventor
Олег Савельевич Кочетов
Мария Олеговна Стареева
Мария Михайловна Стареева
Анна Михайловна Стареева
Татьяна Дмитриевна Ходакова
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Олег Савельевич Кочетов
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Priority to RU2014125708/02A priority Critical patent/RU2568799C1/en
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Publication of RU2568799C1 publication Critical patent/RU2568799C1/en

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Abstract

FIELD: machine building.
SUBSTANCE: noise suppressor contains a cylindrical casing, end inlet nozzle rigidly connected with central pipe made with perforation. Between the casing and central pipe at least one perforated pipe is located. Pipes are located coaxially with possibility to create resonant cavities. Between the casing and perforated pipe, and in end part of the central pipe the sound absorbing elements are installed. Porosity of the sound absorbing element located between the casing and perforate pipe by 2.5…5.0 times is below the porosity of the sound absorbing element in end part of the central pipe. Sound absorbing elements comprise a smooth surface and a perforated surface between which a multilayer sound absorbing structure is placed and consists of three layers of sound-absorbing material.
EFFECT: increased efficiency of sound suppression.
2 dwg

Description

The invention relates to a technique for damping noise.
The closest technical solution in technical essence is a multi-section silencer according to the patent of the Russian Federation No. 2281405, F01N 1/00 (prototype), containing a cylindrical body, an end outlet pipe, rigidly connected to a central pipe having perforation, perforated partitions are made in the form of coaxially located to the casing and the central pipe of the additional perforated pipe, and the ends of all pipes are rigidly connected to the casing by means of blind partitions.
The disadvantage of the prototype is the relatively low efficiency of sound attenuation due to the possibility of the occurrence of a "radiation effect" and, as a result, the penetration of sound waves both along the axis of the muffler and through its two walls.
The technical result is an increase in the efficiency of sound attenuation due to the exclusion of the "radiation effect" and the penetration of sound waves both along the axis of the silencer and through its two walls by introducing sound-absorbing elements on the propagation path of sound waves.
This is achieved by the fact that in a multi-section silencer containing a cylindrical body, an end inlet pipe rigidly connected to the central pipe having perforation and forming with the body through perforated baffles in the form of at least one additional perforated pipe coaxially located to the body and the central pipe, and the ends of all pipes are rigidly connected to the body by means of continuous partitions, one of which is rigidly connected to the inlet pipe, and the other is located opposite on the side of the pipe, a sound-absorbing element is located between the body and the perforated pipe and a sound-absorbing element is fixed in the end part of the central pipe, fixed by a lock washer, the porosity of the sound-absorbing element located between the body and the perforated pipe is 2.5 ... 5.0 times lower than the porosity of the sound-absorbing element located in the end part of the Central pipe, and the sound-absorbing element contains a smooth and perforated surface, between which is placed a multilayer sound-absorbing I have a structure that consists of three layers of sound-absorbing material, the first layer being more rigid, made solid and profiled and fixed on a smooth surface, and the second layer, softer than the first, made intermittent and located in the focus of the sound-reflecting surfaces of the first layer, and the third layer of the sound-absorbing element is made of foamed sound-absorbing material, for example, construction sealing foam, and is located between the first, more rigid, layer and the perforated surface of the sound-absorption element.
In FIG. 1 shows a frontal section of the proposed silencer, FIG. 2 is a diagram of a sound absorbing element.
The multi-section silencer comprises a cylindrical body 1, an end inlet pipe 2, rigidly connected to a central pipe 3 having a perforation 9. At least one additional perforated pipe 4 with a perforation 10 is located between the body 1 and the central pipe 3, and the pipes are coaxially located form resonant cavities, and the ends of all pipes are connected to the housing 1 by means of solid partitions, one of which is rigidly connected to the inlet pipe 2, and the other 5 is located on the opposite side pipe 2 us. A sound-absorbing element 7 is located between the housing 1 and the perforated pipe 4. At the end of the central pipe 3 there is a sound-absorbing element 8, fixed by a lock washer. Sound-absorbing elements 7 and 8 can be made of both hard sound-absorbing materials, such as Akmigran, Vinipore, etc., and soft, such as mineral wool or fiberglass, then in this case the sound-absorbing elements 7 and 8 should be placed in fiberglass (not shown in the drawing) in order to prevent “absorption” of the sound absorber through the perforation 6.
Multi-section silencer operates as follows.
Sound waves along with a turbulent stream of compressed air enter through the end inlet pipe 2 into the cavity of the central perforated pipe 3, while the phenomenon of radiation effect is completely eliminated due to the presence of a solid partition 5, which acts as a soundproof screen. Resonance cavities formed by coaxially arranged tubes 1, 3, 4, perform the functions of Helmholtz resonators, while the holes 6, 9, 10 of the perforation are the neck of the resonators arranged in series. By choosing the gaps between the pipes 1, 3, 4 and the diameters of the perforation holes 6, 9, 10, you can tune Helmholtz resonators to any frequency band where noise attenuation is required, and any desired efficiency can be achieved by the number of resonant cavities. Due to the presence of several pipes in the proposed silencer, the sound-insulating ability of sound attenuation to the direct penetration of sound waves increases. The resistance of the proposed silencer is small due to the location of the perforation holes in a through-hole design, which allows to increase their throughput. The increase in the efficiency of sound attenuation occurs due to the exclusion of the "radiation effect" and the penetration of sound waves through the walls of the muffler due to the introduction of sound-absorbing elements 7 and 8 on the path of propagation of sound waves.
Moreover, the porosity of the sound-absorbing element 7 is 2.5 ... 5.0 times lower than the porosity of the sound-absorbing element 8 to exclude a possible increase in the resistance of the silencer, which can significantly affect the performance of the equipment.
The coaxial arrangement of the pipes made it possible to significantly simplify the design of the proposed noise suppressor, as well as improve its operation due to the fact that contaminants are easily removed from it: water droplets, oils, which can increase the noise suppressor resistance during long-term operation.
The sound-absorbing element (Fig. 2) is made in the form of a smooth 11 and perforated 12 surfaces, between which is placed a sound-absorbing structure consisting of three layers of sound-absorbing material, the first layer 13 being more rigid, made solid and profiled and fixed on a smooth surface 11, the second layer 14, softer than the first, is intermittent and located in the focus of the sound-reflecting surfaces of the first layer 13.
The intermittent sound-absorbing layer 14, located in the focus of the continuous profiled layer 13, is made in the form of bodies of revolution, for example in the form of balls, ellipsoids of revolution, and is fastened with rods 16 (a section with one rod 16 is shown in the drawing) parallel to smooth 11 and perforated 12 surfaces that are rigidly connected to a smooth surface 11 by means of vertical fastening elements perpendicular to them, for example, in the form of plates 17, one end of which is rigidly fixed to a smooth surface 11, and the second is made in the form of x a collar covering the rod 16 and tightening it with a screw (not shown in the drawing).
The continuous profiled layer 13 of the sound-absorbing element is made of a more rigid sound-absorbing material, in which the reflection coefficient of sound is greater than the sound-absorption coefficient, and the profiles 15 are formed by spherical surfaces interconnected so that as a whole each of the profiles 15 forms an integral dome-shaped profile focusing reflected sound on the same soft intermittent sound-absorbing layer 14.
The third layer 18 of the sound-absorbing element is made of foamed sound-absorbing material, for example, construction sealing foam, which increases the sound-insulating properties of the structure as a whole by filling the voids formed by layers 11 and 12, and also increases the reliability of the structure as a whole when installed on equipment operating in conditions with increased shock and vibration loads. The third layer 18 is located between the first, more rigid, layer 13 and the perforated surface 12 of the sound-absorbing element.
As the sound-absorbing material of the first, more rigid layer 13, a material based on aluminum-containing alloys was used, followed by filling them with titanium hydride or air with a density in the range of 0.5 ... 0.9 kg / m 3 with the following strength properties: compressive strength within 5 ... 10 MPa, bending strength in the range of 10 ... 20 MPa, for example foam aluminum.
As the sound-absorbing material of the second, softer layer 14, rockwool-type mineral wool or URSA-type mineral wool, or P-75 type cotton wool, or glass wool lined with glass wool, or foamed polymer can be used, for example polyethylene or polypropylene.
The material of the perforated surface 12 can be made of solid decorative vibration-damping materials, for example, agate, antivibrate, and shvim plastic compounds, the inner surface of the perforated surface 12 facing the sound-absorbing structure, lined with an acoustically transparent material, for example, fiberglass type E3 -100 or "Poviden" type polymer.
Sound-absorbing element operates as follows.
Sound energy, passing through a layer of perforated surface 12 and a third layer 18 of a sound-absorbing element made of foamed sound-absorbing material, falls on an intermittent sound-absorbing layer 14 located at the focus of a continuous profiled layer 13, where the primary dissipation of sound energy occurs. Then, sound energy enters the continuous profiled layer 13 of sound-absorbing material formed by spherical surfaces forming a solid dome-shaped profile focusing the reflected sound onto a soft sound absorber 14. Here, the sound energy is converted into heat (dissipation, energy dissipation), i.e. in the pores of the sound absorber, which are the Helmholtz resonator model, there are energy losses due to friction, which fluctuates with the excitation frequency of the mass of air in the resonator neck against the walls of the neck itself, which has the form of an extensive network of micropores of the sound absorber. The perforation coefficient of the perforated surface 12 is taken to be equal to or more than 0.25.

Claims (1)

  1. A multi-sectional silencer comprising a cylindrical body, an end inlet pipe rigidly connected to a central pipe made with perforation, and at least one additional perforated pipe is located between the body and the central pipe, and the coaxially arranged pipes are capable of forming resonant cavities , the ends of all pipes are connected to the housing by means of continuous partitions, one of which is rigidly connected to the inlet pipe, and the other is located opposite sound side, between the body and the perforated pipe and in the end part of the central pipe there are sound-absorbing elements, and the porosity of the sound-absorbing element located between the body and the perforated pipe is 2.5 ... 5.0 times lower than the porosity of the sound-absorbing element located in the end part central pipe, characterized in that the sound-absorbing element contains a smooth and perforated surface, between which is placed a multilayer sound-absorbing structure, which consists of three oi of sound-absorbing material, the first layer being more rigid, made solid and profiled and fixed on a smooth surface, the second layer, softer, made intermittent and located at the focus of the sound-reflecting surfaces of the first layer, and the third layer of the sound-absorbing element is foamed and located between the first, more rigid layer and perforated surface of sound-absorbing elements.
RU2014125708/02A 2014-06-25 2014-06-25 Multi-section noise suppressor RU2568799C1 (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2641991C1 (en) * 2016-10-10 2018-01-23 Олег Савельевич Кочетов Multi-section silencer
RU2641993C1 (en) * 2016-10-10 2018-01-23 Олег Савельевич Кочетов Multi-section noise suppressor

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1408030A (en) * 1971-12-06 1975-10-01 Safety Vehicles Develop Silencer for exhaust gases
EP0916906A2 (en) * 1997-11-10 1999-05-19 Stifab Farex AB A sound absorber for ventilation ducts
RU2281405C1 (en) * 2004-12-28 2006-08-10 Олег Савельевич Кочетов Multisectional silencer
RU2328650C1 (en) * 2006-12-11 2008-07-10 Открытое акционерное общество Научно-производственное объединение "Искра" Silencer
RU106658U1 (en) * 2010-07-09 2011-07-20 Общество с ограниченной ответственностью "Инновационный Центр "Опережение" Muffler
RU2511858C1 (en) * 2013-04-10 2014-04-10 Олег Савельевич Кочетов Element of noise muffler by kochetov

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1408030A (en) * 1971-12-06 1975-10-01 Safety Vehicles Develop Silencer for exhaust gases
EP0916906A2 (en) * 1997-11-10 1999-05-19 Stifab Farex AB A sound absorber for ventilation ducts
RU2281405C1 (en) * 2004-12-28 2006-08-10 Олег Савельевич Кочетов Multisectional silencer
RU2328650C1 (en) * 2006-12-11 2008-07-10 Открытое акционерное общество Научно-производственное объединение "Искра" Silencer
RU106658U1 (en) * 2010-07-09 2011-07-20 Общество с ограниченной ответственностью "Инновационный Центр "Опережение" Muffler
RU2511858C1 (en) * 2013-04-10 2014-04-10 Олег Савельевич Кочетов Element of noise muffler by kochetov

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2641991C1 (en) * 2016-10-10 2018-01-23 Олег Савельевич Кочетов Multi-section silencer
RU2641993C1 (en) * 2016-10-10 2018-01-23 Олег Савельевич Кочетов Multi-section noise suppressor

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