RU2528802C1 - Sound absorbing element - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: multilayer sound absorbing structure is placed in a sound absorbing element comprising a smooth surface and a perforated surface. The element is made as rigid and perforated walls, between which the layers of sound reflecting, and sound-proof materials of different density arranged in two layers are located. The layers of sound reflecting material are of complex profile composed of evenly distributed hollow tetrahedrons. The layers of sound reflecting material are made from heat insulation material, plates of basalt-based mineral wool like "Rockwool", or "URSA" mineral wool, or basalt wool of P-75 type, or glass wool lined with a glass felt are used as the above material.

EFFECT: enhanced efficiency of sound absorption and reliability of the structure in general.

4 cl, 1 tbl, 1 dwg

Description

The invention relates to industrial acoustics, and can be used to reduce the noise of the drive machines, facing industrial premises and other sound-absorbing structures.

The closest technical solution to the technical nature and the achieved result is a sound-absorbing element used as a facing of industrial premises, known from the RF patent No. 2463412 (prototype).

The disadvantage of the technical solution adopted as a prototype is the relatively low noise reduction due to the presence of voids between the layers, where there is no sound absorption between the layers of the sound absorber.

The technical result is an increase in the efficiency of sound attenuation and the reliability of the structure as a whole.

This is achieved by the fact that in a sound-absorbing element containing a smooth and perforated surface, between which a multilayer sound-absorbing structure is placed, it is made in the form of rigid and perforated walls, between which are layers of sound-reflecting, as well as sound-absorbing materials of different density, located in two layers, and The layers of sound-reflecting material are made of a complex profile, consisting of uniformly distributed hollow tetrahedrons, which allow reflecting falling in all directions x sound waves, which are located respectively on the rigid and perforated walls, and the layers of sound-reflecting material are made of heat-insulating material that can maintain a given microclimate in the room, and rockwool or mineral wool slabs made of rock wool or mineral wool are used as sound-absorbing material URSA type cotton wool, or P-75 type basalt cotton wool, or glass wool with glass wool lining, and the sound-absorbing element is lined acoustically transparent over its entire surface m material, such as fiberglass type E3-100 or a polymer of the type "visible", and the perforated wall has the following perforation parameters: hole diameter - 3 ÷ 7 mm, perforation percentage 10% ÷ 15%, and the shape of the holes can be made in the form of holes a round, triangular, square, rectangular or rhomboid profile, while in the case of non-circular holes, the conditional diameter should be considered the maximum diameter of the circle inscribed in the polygon.

The drawing shows a diagram of a sound-absorbing element.

The sound-absorbing element is made in the form of rigid 1 and perforated 6 walls, between which are layers of sound-reflecting 2 and 5 materials, as well as sound-absorbing 3 and 4 materials of different densities, located in two layers, the layers of sound-reflecting material made of a complex profile consisting of uniformly distributed hollow tetrahedra, allowing to reflect the sound waves incident in all directions, which are located respectively at the rigid 1 and perforated 6 walls, and the perforated wall has the following the other parameters of perforation: the diameter of the holes is 3 ÷ 7 mm, the percentage of perforation is 10% ÷ 15%, and the shape of the holes can be made in the form of holes of a round, triangular, square, rectangular or rhomboid profile, while in the case of non-circular holes as a conditional diameter should be considered the maximum diameter of the circle inscribed in the polygon.

The perforated wall 6 can be made of structural materials, with a layer of soft vibration-damping material, for example, VD-17 mastic, or “Gerlen-D” type material deposited on one or two sides of the material, and the ratio between the thicknesses of the material and the vibration-damping coating lies in the optimal range of values: 1 / (2.5 ... 3.5).

The perforated wall 6 can be made of stainless steel or a galvanized sheet with a thickness of 0.7 mm with a protective and decorative polymer coating of 50 μm thick or Polyester 25 μm thick, or an aluminum sheet with a thickness of 1.0 mm and a coating thickness of 25 microns. The perforation coefficient of perforated sheets is taken to be equal to or more than 0.25.

As the material of the sound-reflecting layers 2, 5, a material based on aluminum-containing alloys can be 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 in the range of 5 ... 10 MPa, bending strength in the range of 10 ... 20 MPa, for example foam aluminum.

As the material of the sound-reflecting layers 2, 5, sound-proofing plates based on glass staple fiber of the “Shumostop” type with a material density of 60 ÷ 80 kg / m ³ can be used.

To reduce or correct the reverberation time of premises, sound-absorbing materials and structures (sound absorbers) are used in its decoration.

Porous sound absorbers are made in the form of plates that are attached to the enclosing surfaces directly or on the basis of light and porous mineral piece materials - pumice, vermiculite, kaolin, slags, etc. with cement or other binder. Such materials are strong enough and can be used to reduce noise in corridors, foyers, staircases of public and industrial buildings.

Table 1 Material, object 125 250 500 1000 2000 4000 Unpainted concrete 0.01 0.012 0.016 0.019 0.023 0.035 Painted concrete 0.009 0.011 0.014 0.016 0.017 0.018 Marble 0.01 0.01 0.01 0.013 0.015 0.017 Brick unpainted 0.024 0.025 0.031 0.042 0.049 0.07 Painted brick 0.012 0.013 0.017 0.02 0.023 0.025 Gypsum plaster 0.02 0.026 0.04 0.062 0.058 0.028 Lime plaster 0.024 0.046 0.06 0.085 0.043 0.056 Fiberboard (MDF), 12 mm 0.22 0.3 0.34 0.32 0.41 0.42 Gypsum panel 10 mm to 100 mm from the wall 0.41 0.28 0.15 0.06 0.05 0.02 Parquet floor 0.04 0.04 0.07 0.06 0.06 0.07 Boardwalk Floor 0.2 0.15 0.12 0.1 0.08 0.07 Metlakh tile 0.01 0.01 0.02 0.02 0.02 0.03 Glazed Window Bindings 0.35 0.25 0.18 0.12 0.07 0.04 Lacquered Doors 0.03 0.02 0.05 0.04 0.04 0.04 Wool carpet 9 mm thick for concrete 0.02 0.08 0.21 0.26 0.27 0.37

The raw materials for their production are wood fibers, mineral wool, glass wool, synthetic fibers. The surface of the fibrous absorbers is treated with special porous paints that allow air to pass through (for example, Acutex T) or coated with breathable fabrics or non-woven materials, such as Loutra-force.

Currently, fibrous sound absorbers are the most common in construction practice. They not only proved to be the most effective from an acoustic point of view in a wide frequency range, but also meet the increased requirements for room design.

In fibrous absorbers, the dissipation of the energy of air vibrations and its transformation into heat occurs at several physical levels. Firstly, due to the viscosity of the air, and there is a lot of it in the interfiber space, the oscillation of air particles inside the absorber leads to friction. In addition, air is rubbed against fibers whose surface is also large. Thirdly, the fibers rub against each other and, finally, energy dissipation occurs due to the friction of the crystals of the fibers themselves. This explains that at medium and high frequencies the sound absorption coefficient of fibrous materials is in the range of 0.4 ... 1.0. The sound absorption coefficient a is equal to the ratio of the energy of the air vibration not reflected (absorbed inside and passed through) from the surface to the total energy acting on the surface. Sound absorption coefficients for most building materials are shown in table 1.

As sound-absorbing material of layers 3 and 4, rockwool-type mineral wool or URSA-type mineral wool, or P-75-type basalt wool or glass wool lined with glass wool, or foamed polymer, such as polyethylene or polypropylene. The surface of the fibrous absorbers is treated with special porous air-permeable paints (e.g. Acutex T) or coated with breathable fabrics or non-woven materials, such as Lutrasil.

The perforated wall 6 is made of solid decorative vibration-damping materials, for example, Agate, Anti-Vibrate, Shvim plastic compounds, and the inner surface of the perforated surface facing the sound-absorbing structure is lined with an acoustically transparent material, such as fiberglass type E3-100 or polymer such as "povid", or non-woven materials, such as "lutrasilom".

Sound-absorbing element operates as follows.

Sound energy from equipment located in the room, or another object that emits intense noise, passing through the perforated wall 6, enters layers 2 and 5 of the sound-reflecting material of a complex profile, consisting of uniformly distributed hollow tetrahedrons, which allow reflecting sound waves incident in all directions , and which are located respectively at the rigid 1 and perforated 6 walls, and then on layers 3 and 4 of soft sound-absorbing material of different densities located in two layers (for example, made th from basalt or glass fibers). In fibrous absorbers, the dissipation of the energy of air vibrations and its transformation into heat occurs at several physical levels. Firstly, due to the viscosity of the air, and there is a lot of it in the interfiber space, the oscillation of air particles inside the absorber leads to friction. The transition of sound energy into thermal energy (dissipation, energy dissipation) occurs in the pores of the sound absorber, which are the Helmholtz resonator model, where energy losses occur due to friction of the mass of air in the resonator neck oscillating with the excitation frequency against the wall of the neck itself, which has the form branched network of pore sound absorbers. In addition, there is air friction on fibers, the surface of which is also large. Thirdly, the fibers rub against each other and, finally, energy dissipation occurs due to the friction of the crystals of the fibers themselves. This explains that at medium and high frequencies the sound absorption coefficient of fibrous materials is in the range of 0.4 ... 1.0.

Claims (4)

1. Sound-absorbing element containing a smooth and perforated surface, between which is placed a multilayer sound-absorbing structure, characterized in that it is made in the form of rigid and perforated walls, between which are layers of sound-reflecting, as well as sound-absorbing materials of different densities, located in two layers, and The layers of sound-reflecting material are made of a complex profile, consisting of uniformly distributed hollow tetrahedrons, which allow reflecting falling in all directions uk waves, which are located respectively on rigid and perforated walls, and the layers of sound-reflecting material are made of heat-insulating material that can maintain a given microclimate in the room, and rockwool or rockwool type mineral wool slabs or rock wool of the type used as sound-absorbing material “URSA”, or P-75 type basalt wool, or glass wool with glass-fiber facing, moreover, the sound-absorbing element is lined with an acoustically transparent mat over its entire surface with a series, for example, fiberglass type E3-100 or a polymer of the type "visible", and the perforated wall has the following perforation parameters: hole diameter - 3 ÷ 7 mm, perforation percentage 10% ÷ 15%, and the shape of the holes can be made in the form of round holes , triangular, square, rectangular or rhomboid profile, while in the case of non-circular holes, the maximum diameter of a circle inscribed in a polygon should be considered as a conditional diameter. 2. The sound-absorbing element according to claim 1, characterized in that the porous sound-absorbing material is used as sound-absorbing material, for example, foam aluminum or cermets or a stone shell with a degree of porosity in the range of optimal values: 30 ÷ 45%, or metal foam, or material in the form of compressed crumb from solid vibration-damping materials, for example elastomer, polyurethane, or plastic compound such as Agate, Anti-Vibrate, Shvim, and the size of the fractions of the crumb lies in the optimal range of values : 0.3 ... 2.5 mm, and also porous mineral piece materials, for example pumice, vermiculite, kaolin, slags with cement or other binder, or synthetic fibers can be used, while the surface of the fibrous absorbers is treated with special porous paints that allow air to pass through for example, type Acutex T or coated with breathable fabrics or nonwoven materials, such as Lutrasil. 3. The sound-absorbing element according to claim 1, characterized in that a material based on aluminum-containing alloys is used as a sound-reflecting material, 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 in the range of 5 ... 10 MPa, bending strength in the range of 10 ... 20 MPa, for example foamed aluminum, or soundproofing boards based on glass staple fiber of the “Shumostop” type with a material density of 60 ÷ 80 kg / m ³ . 4. The 3-sound-absorbing element according to claim 1, characterized in that the perforated wall can be made of structural materials with a layer of soft vibration-damping material, for example, VD-17 mastic or “Gerlen-D” type, applied on their surface. the ratio between the thicknesses of the material and the vibration damping coating lies in the optimal range of values: 1 / (2.5 ... 3.5), or stainless steel, or a galvanized sheet 0.7 mm thick with a polymer protective and decorative coating of the “Pural” type 50 microns thick m, or "Polyester" with a thickness of 25 microns, or an aluminum sheet with a thickness of 1.0 mm and a coating thickness of 25 microns, or from solid decorative vibration-damping materials, such as plastic compounds such as "Agate", "Anti-Vibrate", "Shvim", and the inner surface is perforated the surface facing the sound-absorbing structure is lined with an acoustically transparent non-woven material, such as Lutrasil.

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