RU2551146C1 - Resonant acoustic absorber by kochetov - Google Patents

Abstract

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

Description

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

Known designs of piece sound absorbers made in the form of volumetric parallelepipeds, cubic, conical, the cavities of which are filled with sound-absorbing material [1, 2, 3, 4]. Currently, fibrous sound absorbers are the most common in construction practice.

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

Known conical piece sound absorber according to the patent of the Russian Federation No. 22822004 [5], consisting of a rigid frame suspended by hooks on cables to the ceiling of the industrial building, with a sound-absorbing material located inside the frame wrapped in a mesh nylon fabric, the frame is made in the form of a cone attached to its lower flange with a hemisphere also containing sound-absorbing material wrapped in a mesh nylon fabric or fiberglass, and filling with sound-absorbing material can be like with air cavities located on the periphery of the hemisphere, and inside it in a checkerboard pattern along three coordinate planes.

Its disadvantage is the relatively low efficiency of sound attenuation at high frequencies due to the lack of sound-reflecting layers that perform sound insulation functions at high frequencies.

Known cylindrical resonant piece sound absorber according to the patent of the Russian Federation No. 23033679 [6], consisting of a rigid frame suspended by hooks on cables to the ceiling of the industrial building, with a sound-absorbing material located inside the frame wrapped in a mesh nylon fabric, the frame is made cylindrical in the form of a perforated glass and round lid, inside which is located, rigidly fixed on the axis of the glass of the Central rod, on which are mounted with the possibility of fixing round partitions Inside a sound-absorbing material which is wrapped hexanoic mesh cloth.

The disadvantage is the relatively low noise attenuation efficiency at low frequencies due to the cramped dimensions for placing resonant cameras.

Known cubic piece sound absorber according to the patent of the Russian Federation No. 2334062 [7], consisting of a rigid frame suspended by hooks on cables to the ceiling of the industrial building, with a sound-absorbing material located inside the frame wrapped in a mesh nylon fabric, the frame is made in the form of two cubic surfaces, one of which, the outer one, is perforated, and the other, the inner one, is acoustically transparent, and the sound-absorbing material wrapped in a mesh nylon fabric is located in the gap between the frame themselves, which are interconnected by resonant inserts of different diameters, and the internal cavity is 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 that perform the functions of sound insulation at high frequencies.

Known volumetric piece sound absorbers according to the patent of the Russian Federation No. 2354786 [8] and the Russian Federation No. 2485256 [9], consisting of a rigid frame suspended on a fastener to the ceiling of an industrial building, the frame is made with sound-absorbing material wrapped in an acoustically transparent material.

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

The closest technical solution in terms of technical nature and the achieved result is a piece sound absorber according to the patent of the Russian Federation No. 2485256 [10], containing a rigid perforated frame, inside which a sound-absorbing material is placed, the frame is made of the lower part of the conical shape with a cover and the upper part of the cylindrical shape, which is attached to the cover of the lower part of the perforated frame by means of a vibration damping pad, which allows damping high-frequency vibrations, while to the upper part is cylindrical about the perforated carcass, an element is pivotally fixed by means of which the carcass is attached to the desired object, for example, the ceiling of the production room, and the cavities of the lower and upper parts of the perforated carcass are filled with sound-absorbing materials of different densities, with at least one around the upper part of the cylindrical a screw sound-absorbing element of a piece absorber, made in the form of a cylindrical helical spring from a dense non-combustible sound-absorbing th material.

The disadvantages of this piece of sound absorber is the relatively low noise reduction efficiency at low and medium frequencies due to the lack of volume cavities for Helmholtz resonators and cavities filled with a sound absorber, i.e. absorbers of various densities.

EFFECT: increased efficiency of sound attenuation at high frequencies by introducing volume cavities for Helmholtz resonators into a piece sound absorber, which increase efficiency at high frequencies.

This is achieved by the fact that in a resonant sound absorber containing a rigid frame of the upper active part and the lower reactive part, the reactive part is made in the form of at least three coaxially and axisymmetrically located resonant cylinders, the cavities of which are provided with openings of different diameters that perform the functions of the mouths of the resonator Helmholtz, and the support disks located at the ends of the cylinders rigidly and hermetically connect them together, forming the reactive part of the rigid frame of the sound absorber, with the top The active part is made in the form of a rigid perforated cylindrical shell with a perforated lid and a solid base, the cavity of the cylindrical shell is filled with sound-absorbing material, and the connection of the upper and lower parts is made by means of an elastic damping element that allows damping high-frequency vibrations, while to the perforated cover of the perforated cylindrical the shell is pivotally fixed to the element by which the frame is attached to the desired object, and around the perforated at least one helical sound-absorbing element is arranged in the form of a cylindrical helical spring, enclosing the shell and resting on a support disk connected to the reactive part of the sound absorber.

The drawing shows a diagram of a resonant sound absorber.

The resonant sound absorber contains a rigid frame of the upper active part 1 and the lower reactive part 4, made in the form of at least three coaxially and axisymmetrically located resonant cylinders 8, 9 and 11, the cavities of which are provided with openings 7, 10, 12 of different diameters, performing functions of the necks of the Helmholtz resonator. The supporting disks 13 and 14, located at the ends of the cylinders, rigidly and hermetically connect them together, forming the reactive part 4 of the rigid frame of the sound absorber.

The upper, active, part 1 is made in the form of a rigid perforated cylindrical shell 2 with a perforated lid and a solid base, and the cavity of the cylindrical shell is filled with sound-absorbing material. The connection of the upper 1 and lower 4 parts is made by means of an elastic damping element 5, which allows damping high-frequency vibrations, while an element is pivotally fixed to the perforated cover of the perforated cylindrical shell 2, by which the frame is attached to the desired object, for example, the ceiling of the room.

Around the perforated cylindrical shell 2 is located at least one screw sound-absorbing element 3, made in the form of a cylindrical helical spring, covering the shell 2 and resting on the supporting disk 6 connected to the reactive part 4 of the sound absorber.

The screw sound-absorbing element 3 is made in the form of a hollow screw sound-absorbing element formed by the external and internal screw surfaces forming a cavity (not shown in the drawing), while the space formed by the external and internal screw surfaces is filled with sound-absorbing material (not shown in the drawing) with a density less than that of a screw sound-absorbing element 3.

The resonant sound absorber operates as follows.

Sound waves propagating at an industrial or transport facility interact with the sound-absorbing material of a screw sound-absorbing element 3 located in the upper active part 1 of the frame, as well as in the perforated cylindrical shell 2, while there is a decrease in noise at low, medium and high frequencies, respectively.

The connection of the upper 1 and lower 4 parts of the frame by means of an elastic damping element 5 allows you to damp high-frequency vibrations that can be emitted by a rigid frame, which allows it to be used to reduce noise on transport objects. Sound absorption at medium and high frequencies occurs due to the acoustic effect, built on the principle of Helmholtz resonators, formed by the air cavities of resonant cylinders 8, 9 and 11, the cavities of which are provided with openings 7, 10, 12 of different diameters, which serve as the neck of the Helmholtz resonator, to suppress noise in a given frequency band, while in order to suppress sound vibrations in the desired sound frequency range, as a rule, large volumes of cavities of resonant cylinders 8, 9 and 11 are chosen to suppress noise in low-frequency range, and small - in the medium and high frequencies. The interaction of sound waves with a screw sound-absorbing element 3 leads to noise attenuation in the high frequency range, and the implementation of a sound absorber from non-combustible materials makes the design fireproof.

Information sources

1. Kochetov O.S., Sazhin B.S. Noise and vibration reduction in production: theory, calculation, technical solutions. - M.: MSTU. A.N. Kosygina, 2001 .-- 319 p. (Fig. P.III.10, p. 263).

2. Kochetov O.S. Textile vibroacoustics. Textbook for universities. - M.: MSTU. A.N. Kosygina, the group "Sauvage Bevo" 2003. - 191 p. (Fig. A.2, p. 176).

3. Kochetov OS Laboratory workshop on industrial sanitation. Textbook for universities. - M.: MSTU. A.N. Kosygina, the group "Sovezh Bevo" 2004. - 168 p. (Fig.6.6, p. 120).

4. Kochetov O.S. Sound-absorbing structures to reduce noise in the workplace of industrial premises. The journal "Labor safety in industry", No. 11, 2010, pp. 46-50 (Fig. 1; p. 48 and Fig. 2; p. 48).

5. Kochetov O.S., Kochetova M.O., Khodakova T.D., Elin A.M. Conical piece sound absorber // Patent for invention No. 2282004. Published on August 20, 2006. Bulletin of inventions No. 23.

6. Kochetov O.S., Kochetova M.O., Khodakova T.D. Cylindrical resonant piece sound absorber // Patent for invention No. 2303679. Published on July 27th, 2007. Bulletin of inventions No. 21.

7. Kochetov O.S., Kochetova M.O., Khodakova T.D. Cubic piece sound absorber // Patent for invention No. 2334062. Published on September 20, 2008. Bulletin of inventions No. 26.

8. Kochetov O.S., Kochetova M.O., Kochetov S.S., Kochetov Sergey Sergeevich. Volumetric piece sound absorber // Patent for invention No. 2354786. Published on May 10th, 2009. Bulletin of inventions No. 13.

9. Kochetov O.S. Piece sound absorber // Patent for invention No. 2485256. Published 06/20/2013. Bulletin of inventions No. 17.

10. Kochetov O.S., Stareeva M.O. Piece sound absorber // RF patent for the invention No. 2495202. Published 10/10/2013. Bulletin of inventions No. 28.

Claims (2)

1. The resonant sound absorber containing a rigid frame of the upper active part and the lower reactive part, characterized in that the reactive part is made in the form of at least three coaxially and axisymmetrically located resonant cylinders, the cavities of which are provided with holes of different diameters, performing the functions of the neck of the resonator Helmholtz, and the supporting disks located at the ends of the cylinders rigidly and hermetically connect them together, forming the reactive part of the rigid frame of the sound absorber, while the upper , the active part is made in the form of a rigid perforated cylindrical shell with a perforated cover and a solid base, and the cavity of the cylindrical shell is filled with sound-absorbing material, and the connection of the upper and lower parts is made by means of an elastic damping element that allows damping high-frequency vibrations, while to the perforated cover of the perforated cylindrical shell an element is pivotally fixed by means of which the frame is attached to the desired object, and around the perforated hydrochloric cylindrical shell is at least one sound-absorbing helical element made in the form of a coil spring encompassing shroud and resting in the support disc connected to the reactive part of the absorber. 2. The resonant sound absorber according to claim 1, characterized in that the screw sound-absorbing element is made in the form of a hollow screw sound-absorbing element formed by the external and internal screw surfaces forming a cavity, while the space formed by the external and internal screw surfaces is filled with sound-absorbing material with a density less than that of a screw sound-absorbing element.

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