RU172683U1 - Resonator panel - Google Patents

Abstract

The proposed technical solution relates to devices used in the construction of structures for protection against noise, and relates to the design features of building panels, which reduce noise levels to standards when installed in a protected area. The panel has a frame base of wooden impregnated bars. The space between the front and rear walls contains a sound absorber and an air cavity in which stiffeners are placed diagonally. An element for attaching panels is installed on the upper and lower bars of the frame when they are assembled into the screen in the form of an elastic tape. The front skin is made in the form of a grid and a clamping grill with rails installed with a slotted gap, providing a snug fit of the grid to the plate. The gap between the rails in the grating is defined as a function of the frequency of the acoustic wave. The calculation is carried out according to the well-known formula. In combination with a sound absorber and an air cavity inside the device, the panel acts as a Helmholtz resonator, providing sound absorption of a wide range of acoustic waves. The result obtained is confirmed by measurements of noise behind screens equipped with such panels. The technological advantage of the development is the simplicity of maneuvering when equipping and repairing protective shields passing through a variety of technogenic zones with resonator arrays tuned to the wave frequencies of various noise pollution objects. 2 ill.

Description

The technical solution claimed as a utility model relates to industrial construction, and specifically to protection from acoustic waves generated in open technosphere zones during the operation of various machines and mechanisms and having the most diverse spectrum of sound waves from low to high frequency vibrations in their specificity.

A wide range of various developments are known in the prior art regarding noise protection by either simply reflecting it or absorbing it. To absorb noise at medium and high frequencies, various sound-absorbing materials are used. To achieve sound absorption at low frequencies, resonant absorbers are used, they are a combination of Helmholtz resonators combined in a single design [Bulkin VV, Belyaev V.E., Sergeev V.N. Design calculations of elements of RES in the conditions of mechanical and acoustic influences: Textbook. allowance / Ed. V.V. Bulkin. - Murom: CPI MI VlSU, 2004. - 132 s]. Such devices are widely used to create a given acoustic spectral characteristic.

Noise-absorbing panels are known, consisting of a housing with slotted traps and noise absorption elements located inside the housing. The mechanism of sound absorption consists in the passage of sound and other waves through slot traps into the body, deformation of the noise absorption element due to the action of waves on it and the dispersion of energy from sound and other waves on the noise absorption element. Such panels include panels described in RF patents No. 2266997, No. 2222662, No. 2176005, etc. The disadvantages of these absorbers are their lack of versatility when changing the frequency spectrum in the acoustic noise picture of the environment, as well as the difficulty of ensuring a small thickness of the screen structure and its inconstancy, this is due to the need to change the depth of the resonators depending on the changing frequency spectrum of acoustic noise, as well as the insufficient efficiency of sound attenuation, since all its internal resonators are tuned absorption of acoustic vibrations of only a certain frequency, while sound excitations on modern machines are usually broadband, which is caused by the existence of a large number of independent sound sources and the irregularity of certain physical processes.

, где d - диаметр отверстия в сменном элементе, м; f - резонансная частота, Гц; L - расстояние между отверстиями, м; h - расстояние между задней внутренней стенкой короба и окончанием сменного элемента, м; 1 - длина сменного элемента, м; с - скорость звука в воздухе при 20°С, обеспечить требуемый спектр поглощаемых частот. В патенте тех же разработчиков ПМ №139581 описана конструкция шумозащитнного устройства, где шумопроникающие отверстия выполнены в виде вертикально расположенных щелей, при этом профиль короба построен таким образом, чтобы расстояние между внутренними поверхностями задней стенки короба и панели было непостоянным, а ширина щели, ее глубина и изменяющееся по вертикали расстояние между внутренними поверхностями задней стенки короба и панели выбираются таким образом, чтобы в соответствии с зависимостью

, где h - расстояние между внутренними поверхностями панели и задней стенки короба, м; b - ширина щели, м; f - резонансная частота, Гц; L - ширина реек (расстояние между щелями), м; 1 - глубина щели, м; с - скорость звука в воздухе при 20°С, обеспечить требуемый спектр поглощаемых частот. Наличие щелей на панели обеспечивает образование совокупности резонаторов Гельмгольца, что и позволяет реализовать поглощение (ослабление) акустошумового сигнала, достигающего зоны установки экрана. Ширина и глубина щели, расстояние между внутренними поверхностями задней стенки короба и панели определяются исходя из диапазона частот, в котором необходимо обеспечить шумопоглощение. Таким образом, устройство реализует совокупность резонаторов Гельмгольца щелевого типа. При известном диапазоне частот, в котором необходимо осуществить поглощение, может быть сформировано такое сочетание основных размеров, при которых обеспечивается эффективное поглощение акустического шума в выбранном диапазоне частот. Вертикальное расположение резонаторов позволит получить возможность поглощения акустического шума в широком диапазоне частот без увеличения толщины экрана.The design of a noise absorber with openings for the passage of waves in the form of openings into which replaceable elements for selective damping of an acoustic wave are inserted is described (patent for PM No. 139578). Selection of replaceable elements and their placement is carried out by selection of distances and sizes inside the panel according to the formula in such a way that, in accordance with the dependence

where d is the diameter of the hole in the replaceable element, m; f is the resonant frequency, Hz; L is the distance between the holes, m; h is the distance between the rear inner wall of the box and the end of the replaceable element, m; 1 - the length of the replaceable element, m; c - the speed of sound in air at 20 ° С, to provide the required spectrum of absorbed frequencies. The patent of the same developers PM No. 139581 describes the design of a noise-proofing device, where the noise-penetrating holes are made in the form of vertically located slits, while the profile of the box is constructed so that the distance between the inner surfaces of the back wall of the box and the panel is not constant, and the width of the slot, its depth and the vertically variable distance between the inner surfaces of the rear wall of the box and the panel are selected so that in accordance with the dependence

where h is the distance between the inner surfaces of the panel and the rear wall of the box, m; b - slot width, m; f is the resonant frequency, Hz; L is the width of the rails (the distance between the cracks), m; 1 - slot depth, m; c - the speed of sound in air at 20 ° С, to provide the required spectrum of absorbed frequencies. The presence of slots on the panel provides the formation of a combination of Helmholtz resonators, which allows the absorption (attenuation) of the acoustic noise signal to reach the screen installation area. The width and depth of the gap, the distance between the inner surfaces of the rear wall of the box and panel are determined based on the frequency range in which it is necessary to provide noise absorption. Thus, the device implements a set of slotted Helmholtz resonators. With a known frequency range in which it is necessary to absorb, such a combination of basic dimensions can be formed that ensures effective absorption of acoustic noise in a selected frequency range. The vertical arrangement of the resonators will make it possible to absorb acoustic noise in a wide frequency range without increasing the thickness of the screen.

The patents described above are used to reduce noise only by enhancing the resonance effect inside the device. There is no sound-absorbing material in the structures, which makes the structure clearly aimed at one frequency and have small dimensions.

The disadvantage of these absorbers is their lack of versatility when changing the frequency spectrum in the noise picture of the environment, as well as the complicated technology of their manufacture and remounting to tune to the desired frequency, which does not allow them to be recommended for the manufacture of large-scale noise protection devices, for example, along highways and railways .

To solve the problem of large-scale and effective protection against noise pollution in open industrial areas, the manufacture of noise screens according to patent PM No. 104943 is widely implemented in practice. The screen is assembled from panels made in the form of a wooden frame containing a mineral wool slab and walls in the form of wooden sheathing from boards and battens, while from the side of the noise source, a grid is installed around the frame perimeter, pressed against the noise absorber by rails with a gap of at least 1/3 of the width of the battens . The panels are fastened to the screen through a rubber harness installed along the outer edge of the frame to ensure their tight fit, the panels are attached to the I-beam by a pressure corner. The main elements for noise absorption of such a panel are a mineral wool plate and an air cavity formed between the back wall and the plate, as well as the front wall structure facing the noise source, in the form of a grid and face rails with a fixed mesh size and a gap between the rails. However, the sound-absorbing properties of such panels are not sufficiently effective for low-frequency acoustic waves.

The objective of the proposed technical solution is to improve the design of the device with the aim of expanding the use of sound-absorbing panels in various acoustic environments and, ultimately, increasing the efficiency of protection of open industrial areas, as well as simplifying the technology of assembly and operation of noise screens from such panels.

, где d - величина зазора м; f - резонансная частота, Гц; L - ширина рейки м; h - расстояние между задней внутренней стенкой короба и плитой, м; 1 - длина щели, м; с - скорость звука в воздухе при 20°С.The problem was solved by manufacturing the front wall of the panel from a grid and a lattice assembled from front rails with a gap, the size of which is determined by the formula

where d is the size of the gap m; f is the resonant frequency, Hz; L is the width of the rail m; h is the distance between the rear inner wall of the box and the stove, m; 1 - slot length, m; C is the speed of sound in air at 20 ° C.

The achieved technical result of this design solution is to ensure a reliable fit of the grid to the plate, which enhances the resonant capabilities of the device as a whole, and the size of the passage gap between the rails in the grating, fixed depending on the wave frequency, ensures reliable sound absorption of the acoustic wave with such a frequency. This allows you to make screens with combinations of panels for different resonant frequencies.

The proposed solution is illustrated by drawings. In FIG. 1 shows a General view of the device. In FIG. 2 - the design of the clamping lattice.

The resonator panel is arranged as follows: it contains a rectangular frame frame (pos. 1 and 2), reinforced with two stiffening ribs (pos. 8), a front skin made in the form of a mesh (pos. 7) and a clamping grille (pos. 11), consisting of horizontally spaced rails mounted on vertical slats (key 12). The rear wall (item 4) is made in the form of a set of tongue-and-groove boards. A filler (pos. 5 and 6) is installed in the cavity between the casing, attached to the frame with diagonals (pos. 10). A seal is attached to the frame (key 9). The design of the lattice (Fig. 2) is quite simple. The slats at their ends in a horizontal position are attached in any way to the guide rails. The gap between the rails is set by calculation according to the well-known formula as a function of the frequency of the acoustic wave. The clamping grids are installed on the front wall along the panel frame using nails or self-tapping screws.

Tests of panels with resonator arrays of different gaps between the rails showed positive results. Panels with resonators are mounted around a source of low-frequency noise, such as a transformer. The necessary gaps between the rails in the clamping grid are selected at the design stage. Using the above formula, the structural parameters of the clamping grids tuned to a specific resonant frequency of the acoustic wave are calculated. For example, with a gap width of 1 mm, it is determined by frequencies of 125-180 Hz. A clamping front grille assembled from front battens with a wooden plank thickness of 20 mm, with a plank width of 50 mm and a gap width of 1 mm is capable of absorbing a wave with a frequency of 157 Hz generated by transformer substations installed in the city limits.

For a gap width of 2 mm, the resonant frequency will be 220 Hz, where the sound absorption will reach almost 1. When using the material in the structure, the sound absorption will work at frequencies from 200 Hz to 240 Hz. With a gap width of 3 mm, noise will be reduced in the range from 240 Hz to 280 Hz. With a gap width of 5 mm from 310 to 350 Hz, with a gap width of 10 mm from 440 to 480 Hz. Those. Considering the panel design, maximum sound absorption in the range up to 500 Hz is achieved.

Thus, panels tuned using a grating with predetermined gaps between the rails to a specific frequency of the sound wave operate as Helmholtz resonators. In combination with sound-absorbing material inside the panel, such panels provide noise protection over a wider range of acoustic waves. Such panels mounted around a noise source will reduce sound pressure levels from the source over the entire frequency range.

The paneling of the treated wood provides good compatibility with the architecture of the building in the presence of reliable soundproofing qualities. The panels meet the requirements of SNiP and are recommended for use for installation in screens. Simplification of the technology for assembling screens, their maintenance during operation, consists in the easy replacement of clamping grids with grids with the necessary fixed slotted gaps of the rails, depending on the type of noise-generating object.

Claims (2)

1. The resonator panel in the form of a wooden rectangular frame made up of wooden blocks containing a stiffener and a mineral wool plate placed in the cavity between the front and rear walls, while the back wall sheathing is solid, and the front facing the noise source is made of polymer grids and rails installed on the grid with a slotted gap, providing a snug fit of the grid to the plate, characterized in that the rails in a horizontal position are attached at the ends to vertical strips with a Hovhan presser lattice, while the magnitude of the gap between them is determined by a known calculation formula as a function of the resonant frequency of the acoustic wave. 2. The device according to p. 1, characterized in that the size of the gap between the rails of the lattice, calculated in accordance with the dependence

where d is the gap, m; f is the resonant frequency, Hz; L is the width of the rails, m; h is the distance between the rear inner wall of the box and the stove, m; l is the length of the slit, m; c - the speed of sound in air at 20 ° C, provides absorption of the acoustic wave of the required spectrum.

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