Resonant acoustic absorber by kochetov

FIELD: machine building.

SUBSTANCE: resonant acoustic absorber comprises a rigid frame consisting of an upper active part and a lower reactive part. The reactive part is made as three coaxial and axisymmetrical resonant cylinders with their cavities being fitted by holes of different diameter serving as Helmholtz resonator necks. Supporting disks set at the cylinder ends connect the latter to each other in rigid and leaktight manner forming the reactive part of the rigid frame of the acoustic absorber. The upper active part is made in the form of a rigid perforated cylindrical shell with a perforated cover and a solid base. The cavity of the cylindrical shell is filled with sound absorbing material. At least one spiral acoustic absorbing element in the form of a cylindrical coil spring enclosing the shell is mounted around the perforated cylindrical shell. The upper and lower parts are interconnected by a resilient damping element.

EFFECT: improved efficiency of noise suppression at high frequencies.

2 cl, 1 dwg

 

The invention relates to noise reduction in industrial and transport objects.

Known design piece sound absorbers, made in the form of a volume of parallelepiped, cube-shaped, conical, cavity filled with sound absorbing material[1, 2, 3, 4]. Currently the fibrous absorbers are most commonly used in construction practice.

The disadvantages of the known piece of absorbers are the relatively low efficiency at low and medium frequencies, and they do not meet the increased requirements to the design space.

Known conical piece sound absorber according to the patent of Russian Federation №2282004 [5], consisting of a rigid frame, suspended from the hooks on ropes to the ceiling of the production building located inside the frame absorbent material wrapped mesh nylon cloth, the frame is shaped in the form of a cone attached to its lower flange hemisphere, also containing absorbent material wrapped mesh nylon cloth or fiberglass, and a filling of sound absorbing material may be air cavities located on the periphery of the hemisphere, and inside her in a checkerboard pattern on the three coordinate planes.

A disadvantage is its CPA�additional low efficiency of sound attenuation at high frequencies due to the lack of sound-reflecting layer, performing the functions of sound insulation at higher frequencies.

Known cylindrical resonant single-piece sound absorber according to the patent of Russian Federation №2303679 [6], consisting of a rigid frame, suspended from the hooks on ropes to the ceiling of the production building located inside the frame absorbent material wrapped mesh nylon cloth, the frame is made in the form of a cylindrical perforated glass and perforated round cap, inside of which is rigidly fixed to the nozzle axis of the Central rod, which is installed with the possibility of fixation of the round walls, inside one of which is sound-absorbing material wrapped mesh nylon cloth.

The disadvantage is the relatively low efficiency of sound attenuation at low frequencies due to the constrained size to accommodate resonant chambers.

Known cubic single-piece sound absorber according to the patent of Russian Federation №2334062 [7], consisting of a rigid frame, suspended from the hooks on ropes to the ceiling of the production building located inside the frame absorbent material wrapped mesh nylon cloth, the frame is shaped in the form of two cubic surfaces, one of which is foreign - made perforated and the other internal - acoustically transparent, and SV�capogrossi material, wrapped mesh nylon cloth, is located in the interval between the frames, which are interconnected by means of resonant inserts of different diameters and an internal cavity divided by a partition into two resonant cavities, one of which is filled with a sound absorber.

The disadvantage is the relatively low efficiency of sound attenuation at high frequencies due to the lack of sound-reflecting layers, which perform the functions of sound insulation at higher frequencies.

Known piece surround sound absorbers according to the patent of Russian Federation №2354786 [8] and the Russian Federation №2485256 [9], consisting of a rigid frame, suspended on the fastening element to the ceiling of the production building, the frame is made from sound absorbing material wrapped with acoustically transparent material.

Their disadvantage is the relatively low efficiency of sound attenuation at high frequencies due to the lack of Helmholtz resonators.

The closest technical solution to the technical essence and the achieved result is a single-piece sound absorber according to the patent of Russian Federation №2485256 [10], comprising a rigid perforated frame, which is placed inside the sound-absorbing material, the frame is made from the lower part of the conical shape of the lid and the upper part of cylindrical shape, which is attached to cover the lower part of the perforated frame simply�PTO shock-absorbing strip, allowing damping high-frequency vibrations, while the upper part of the cylindrical perforated frame hinged element, with which the frame is attached to a desired object, such as a ceiling industrial premises, and the cavity of the lower and upper parts of the perforated frame filled with sound absorbing materials of different density, and around the upper part of the cylindrical perforated frame is at least one, screw the sound-absorbing element piece of the absorber, made in the form of a cylindrical helical springs made of thick non-combustible absorbent material.

The disadvantages of this piece of insulation material is the relatively low efficiency of noise reduction at low and medium frequencies because of the lack of volume of cavities for Helmholtz resonators and cavities filled with insulation material, i.e. sinks of different densities.

The technical result - improving the efficiency of sound attenuation at high frequencies by introducing into the piece surround sound absorber cavities for Helmholtz resonators, which increase the efficiency at high frequencies.

This is achieved in that in the resonant sound absorber, containing a rigid frame from the top of the active part and the lower reactive �'asti the reactive part is made in the form of at least three coaxially and symmetrically spaced resonant cylinders, the cavity of which is provided with openings of different diameter, acts as the neck of the Helmholtz resonator and the supporting wheels located at the ends of the cylinder, is rigidly and hermetically connect them together, forming a reactive part of a rigid frame of the absorber, while the upper, active portion is formed in the form of a rigid perforated cylindrical shell with a perforated lid and solid base, and the cavity of cylindrical shells filled with sound absorbing material, and the connection of the upper and lower parts is accomplished by means of elastic damping element to damp high frequency oscillations, in this case, by a perforated lid perforated cylindrical shells hinged element, with which the frame is attached to a desired object, and around a perforated cylindrical shells is at least one, screw the sound-absorbing element made in the form of a cylindrical helical spring, covering the sidewall and supported in a support disc connected to the reactive part of the sound absorber.

The drawing shows a diagram of a resonant sound absorber.

Resonant zvukopis�Titel contains a rigid frame from the top of the active part 1 and the lower reactive part 4, made in the form of at least three coaxially and symmetrically spaced resonant cylinders 8, 9 and 11, the cavity of which is provided with openings 7, 10, 12 of different diameter, acts as the neck of the Helmholtz resonator. The supporting wheels 13 and 14 located at the ends of the cylinder, is rigidly and hermetically connect them together, forming a reactive part 4 of the rigid frame of the sound absorber.

The upper, active portion 1 is of a rigid perforated cylindrical shell 2 with a perforated lid and solid base, and the cavity of cylindrical shells filled with sound absorbing material. The connection of the upper 1 and the lower 4 parts is accomplished by means of elastic damping element 5, which allows to dampen high frequency vibrations to the perforated lid perforated cylindrical shell 2 hinged element, with which the frame is attached to a desired object, such as the ceiling of the room.

Around a perforated cylindrical shell 2 is at least one, screw the sound-absorbing element 3 is shaped in the form of a cylindrical helical spring, covering the sidewall 2 and supported in the supporting disk 6 connected to the reactive part 4 absorbers.

Screw the sound-absorbing element 3 is formed � the form of a hollow screw-absorbing element, educated external and internal helical surfaces forming the cavity (not shown), wherein the space formed by outer and inner helical surfaces filled with sound absorbing material (not shown) having a density less than that of the spiral sound-absorbing element 3.

Resonance sound absorber operates as follows.

Sound waves propagating in an industrial or transportation facilities, interact with sound-absorbing sound-absorbing material by the screw element 3, positioned in an upper active portion 1 of the frame, and a perforated cylindrical shell 2, thus there is noise reduction on low, medium and high frequencies, respectively.

The connection of the upper 1 and the lower 4 parts of the frame by means of elastic damping element 5 allows you to dampen high frequency oscillations that can emit a rigid frame, allowing it to be used for noise reduction of transport facilities. The absorption at medium and high frequencies is due to the acoustic effect based on the principle of Helmholtz resonators formed by the resonant air cavities of the cylinders 8, 9 and 11, the cavity of which is provided with openings 7, 10, 12 of different diameter, performing the functions of a flap operation� of the Helmholtz resonator, for damping noise in a given frequency band, in this case to suppress the sound vibrations in the desired audio frequency range, typically, large volumes of resonant cavities of the cylinders 8, 9 and 11 have chosen to suppress noise at low frequencies, and small - mid-and high frequencies. The interaction of sound waves with a spiral sound-absorbing element 3 leads to samohlasen in the high frequency range, and the execution of non-combustible absorbent materials fireproof waterproof design.

Sources of information

1. Kochetov O. S., Sazhin B. S. Reduction of noise and vibration in the production: theory, calculation, technical solutions. - Moscow: MGTU im. A. N. Kosygin, 2001. - 319 S. (Fig.P.III.10, p. 263).

2. Kochetov O. S. Textile vibroacoustic. Textbook for high schools. - Moscow: MGTU im. A. N. Kosygin, group "SOVAG Bevo" 2003. - 191 S. (Fig.P.2, p. 176).

3. Kochetov O. S. Laboratory workshop on industrial hygiene. Textbook for high schools. - Moscow: MGTU im. A. N. Kosygin, group "SOVAG Bevo" 2004. - 168 p. (Fig.6.6, p. 120).

4. Kochetov O. S. acoustic liners to reduce noise in the workplace industrial premises. The magazine "Safety in industry", No. 11, 2010, pp. 46-50 (Fig.1; p. 48 and Fig.2; p. 48).

5. Kochetov O. S., M. O. Kochetova, Khodakov Etc., Elin A. M. Conical piece deadener // Patent n� invention No. 2282004. Published 20.08.2006. Bulletin of inventions No. 23.

6. Kochetov O. S., M. O. Kochetova, Khodakov Etc. Cylindrical resonant piece deadener // Patent for the invention №2303679. Published 27.07.2007. Bulletin of inventions No. 21.

7. Kochetov O. S., M. O. Kochetova, Khodakov Etc. Cubic piece deadener // Patent for the invention №2334062. Published 20.09.2008. Bulletin of inventions No. 26.

8. Kochetov O. S., M. O. Kochetov, S. S. Kochetov, Kochetov, Sergey Sergeevich. Volume of single-piece sound absorber // Patent for the invention №2354786. Published 10.05.2009. Bulletin of inventions No. 13.

9. Kochetov O. S. single-Piece sound absorber // Patent for the invention №2485256. Published on 20.06.2013. Bulletin of inventions No. 17.

10. Kochetov O. S., Stareva M. O. Piece deadener // RF Patent for the invention №2495202. Published on 10.10.2013. Bulletin of inventions No. 28.

1. Resonant sound absorber, containing a rigid frame from the top of the active part and the lower reactive part, characterized in that the reactive part is made in the form of at least three coaxially and symmetrically spaced resonant cylinders, the cavity of which is provided with openings of different diameter, acts as the neck of the Helmholtz resonator and the supporting wheels located at the ends of the cylinder, is rigidly and hermetically connect them with each other, forming �aktivno part of a rigid frame insulation material the upper, active portion is formed in the form of a rigid perforated cylindrical shell with a perforated lid and solid base, and the cavity of cylindrical shells filled with sound absorbing material, and the connection of the upper and lower parts is accomplished by means of elastic damping element to damp high-frequency vibrations, while a perforated lid perforated cylindrical shells hinged element, with which the frame is attached to a desired object, and around a perforated cylindrical shells is at least one, screw the sound-absorbing element made in the form of a cylindrical helical spring, covering the sidewall and supported in a support plate, coupled with the reactive part of the sound absorber.

2. Resonance sound absorber according to claim 1, characterized in that the spiral sound-absorbing element made in the form of a hollow screw-absorbing element formed by outer and inner helical surfaces forming the cavity, wherein the space formed by outer and inner helical surfaces filled with sound absorbing material having a density less than that of the spiral sound-absorbing element.



 

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