RU2150148C1 - Sound-proof screen - Google Patents

Abstract

FIELD: hydroacoustic equipment. SUBSTANCE: device has front and back surfaces which provide sound reflection. Goal of invention is achieved by introduced additional reflecting surface, which is located inside screen and is designed as reinforcing layer. Required impedance value of this layer is achieved by means of shock absorbers, which have respective resonance frequency and are mounted on both sides of layer to achieve sufficient concentration. EFFECT: increased efficiency. dwg

Description

 The invention relates to the field of hydroacoustics, and in particular to a wide class of soundproof structures (screens). Known designs, for example, according to US Pat. NN 4164727, 4399526, 4559255, 4674595. A screen of this kind is used, for example, in the "Device that matches the acoustic signal" according to US patent N 4390976 from 07.28.83, priority from 01/27/1981, MKI H 04 R 17/00, as well as in the "Modular design of high-pressure acoustic screen" according to US patent N 4399526 from 08.16.83, priority from 01/27/81, MKI H 04 R 17/00, which is adopted as a prototype.

 The soundproofing screen described in this patent (see FIG. 1) includes layers of hard 1 and compliant 2 materials connected in the form of a “sandwich”, bordering each other. Hard layers are most often formed of composite materials reinforced with fiberglass, and compliant (elastic) layers are made of elastomeric materials with adjustable air cavities 3.

 It is known (see, for example, VE Glazanov “Shielding of hydroacoustic antennas”, L, Sudostroenie, 1986) that the value of the soundproofing efficiency of screens of this kind is determined mainly by the reflection of sound waves from the boundaries of the screen and medium discharge on the “front” and “back” sides of the screen (relative to the direction of sound propagation). Increasing the thickness of the screen does not change the number and characteristics of the reflecting boundaries, but only reduces its resonant frequency.

 The main disadvantage of the prototype screen design is that the resources for increasing the reflective properties of the boundaries of such a screen design are exhausted, and the possibilities of overlapping the entire specified frequency range by increasing the screen thickness are limited.

 The task of the invention is to increase the efficiency of the soundproofing screen in the low-frequency part of the working frequency range.

 This is achieved by creating additional reflective surfaces in the thickness of the screen without increasing its thickness by installing anti-vibrators on existing hard layers that separate elastic layers with cavities inside these cavities.

 The invention is illustrated by drawings, where in FIG. 2 and FIG. 3 shows sections of some variants of the proposed screen.

 In FIG. 4 presents the results of measurements in the acoustic pipe of sound insulation of one of the options of the proposed screen and the same screen without anti-vibration.

 The proposed acoustic screen, see FIG. 2 and FIG. 3, consists of two elastic layers 1 with cavities 2, separated by a rigid reinforcing layer 3, monolithically adhered to them, and an antivibrator 4 is installed on this layer in each cavity.

 Outside, the layers with cavities are also covered by rigid reinforcing layers 5, which ensure the tightness of the cavities and the structural strength with respect to hydrostatic loads.

 Antivibrator 4 (see, for example, II Klyukin “Combating noise and sound vibration in ships.” L, Sudpromgiz, 1961) is a mechanical resonator excited by vibrations of the screen reinforcing layer from the side of the viscoelastic element of the resonator.

 The achievement of the necessary technical result, that is, an increase in the efficiency of the soundproofing screen, is explained by the addition to the sound-reflecting action of the front and back surfaces of the screen a similar action of an additional reflective surface inside this screen. The impedance of this surface, necessary for such an action, is achieved by placing antivibrators with the necessary concentration on the existing reinforcing layer, which fit geometrically into the cavities provided for by the screen design in viscoelastic layers. The necessary concentration of antivibrators is provided by their bilateral installation on the reinforcing layer, while with a unilateral installation the desired concentration is not achieved.

 From a comparison of the frequency response 6 of the sample screen of the proposed design with the characteristic 7 of the sample of a similar screen without antivibrators (see Fig. 4), it can be seen that the effectiveness of the proposed solution in the low-frequency range can reach 10 - 12 dB. Curve 6 corresponds to antivibrators with a resonant frequency of 1.5 - 2 times lower than that for a screen without antivibrators.

Claims (1)

 A soundproofing screen, consisting of at least two layers of elastic material with cavities in which the anti-vibrators are placed, with a continuous reinforcing layer of hard material between them, and the outside of the screen is covered with solid layers of hard material, characterized in that the anti-vibrators are installed on both sides reinforcing layer.

Images