RU2483971C2 - Vibration and noise protection device for vessel power equipment - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to ship building and concerns creation of vibration and noise protection systems for vessel power equipment. The suggested vibration and noise protection systems for vessel power equipment represent intermediate support made as closed spatial structure predominantly in the form of parallelepiped. Walls, bottom and ceiling of intermediate support represent plates with reinforcement ribs. On inner sides of the plates, soundproof claddings are installed. Closed spatial structure is equipped with at least two internal rigid links in the form of transversal and longitudinal plates rigidly connecting in pairs the middle parts of its opposite walls.

EFFECT: suggested device allows for increasing efficiency of vibration and noise protection of multimachine aggregates.

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Description

The invention relates to the field of shipbuilding and relates to the creation of vibration and noise protection systems for marine power equipment of all types of ships and ships.

The most effective way to reduce the noise and vibration of multi-machine aggregates and installations, which has become widespread in the world, in particular in shipbuilding, is to create blocks of multi-machine aggregates in which

- to reduce the vibration of foundations and the forces acting on the foundations, separate mechanisms are installed through vibration isolators on the supporting intermediate frame structure, which, in turn, is installed on the foundation through the second cascade of vibration isolation;

- to reduce airborne noise generated by the multi-machine unit in the environment, the entire multi-machine unit is closed by a soundproof casing.

. После частоты собственных колебаний несущей рамной конструкции виброизолирующий эффект пропорционален квадрату отношения частот, то есть $$ВИ\equiv \frac{{\omega }^2}{{\omega }_{н}^2}$$

. После частоты собственных колебаний отдельных механизмов (это область частот от 80 до 150 Гц) значение виброизоляции практически не зависит от частоты (В.И.Попков, С.В.Попков. «Колебания механизмов и конструкций». Издательство «Сударыня», С.Петербург, 2009 г.).In the operating frequency range of the vibration isolation system of a multi-machine unit, the lower frequency of which is higher than the highest frequency of natural vibrations of the mechanisms and the unit on the internal and external vibration isolators, the frequency response of the efficiency of the two-stage vibration isolation system has the form shown in figure 1. Figure 1 shows that up to the frequency of natural vibrations of the intermediate frame structure ω _{0, the frame} and mechanisms ω _{0, the mechanism, the} value of the vibration-isolating effect increases in proportion to the fourth degree of the ratio of the current ω to the initial frequency ω _i $$\mathrm{AT}\mathrm{AND}\equiv \frac{{\omega }^{\mathrm{four}}}{{\omega }_n^{\mathrm{four}}}$$

. After the frequency of natural vibrations of the supporting frame structure, the vibration-isolating effect is proportional to the square of the frequency ratio, i.e. $$\mathrm{AT}\mathrm{AND}\equiv \frac{{\mathrm{<figure-callout\; id="2"\; label="\omega "\; filenames="00000004.png,00000005.png"\; state="\{\{state\}\}">\omega </figure-callout>}}^2}{{\mathrm{<figure-callout\; id="2"\; label="\omega \; n"\; filenames="00000004.png,00000005.png"\; state="\{\{state\}\}">\omega \; </figure-callout>}}_n^{}}$$

. After the frequency of natural vibrations of individual mechanisms (this is the frequency range from 80 to 150 Hz), the value of vibration isolation is practically independent of frequency (V. I. Popkov, S. V. Popkov. “Oscillations of mechanisms and structures.” Publisher Sudarynya, S. Petersburg, 2009).

Existing designs of ship multi-machine aggregates have intermediate frames of various designs, but the shape is almost always flat.

There are various currently existing load-bearing structures used as part of two-stage shock absorbers with vibration-insulated equipment placed on them (see the industry standard “Foundations and frames of vibroactive technical means. General technical requirements and norms for acoustic design”. OST 95.0373-83).

A frame structure is also known for the installation of three diesel generators of the main power plant of a cruise ship (Technical Acoustics, Volume 5, Issue 1-2 (15-16), St. Petersburg, 1999, pp. 11-20) - prototype. The device is an intermediate support of a multi-machine unit for placing its equipment, as well as shock-absorbing mounts and sound insulation.

However, since the natural frequencies of such intermediate frames usually do not exceed 20-25 Hz, it is not possible to fully realize the vibration isolation efficiency of the two-stage shock-absorbing mount. In addition, to reduce the airborne noise generated by the multi-machine unit, it is necessary to install a soundproof casing on the frame structure. However, the latter can rarely be implemented in practice, due to the fact that this requires the presence of significant additional volumes in the room where the multi-machine unit is located. This is especially difficult, almost impossible to implement in a ship.

The task of the invention is to increase the efficiency of vibration and noise isolation of multi-machine units.

This is achieved by the fact that in the device of vibration and noise protection of marine power equipment, which is an intermediate support of a multi-machine unit for placing its equipment, shock absorbing fasteners and sound insulation, the latter according to the invention is made in the form of a closed volumetric design in the form of mainly parallelepiped. This three-dimensional structure is composed of reinforced ribs plates, on the inner sides of which are placed soundproof seams. Moreover, the closed volumetric structure inside is equipped with at least two transverse and longitudinal plates rigidly connecting in pairs the middle parts of its opposite walls.

The design of the intermediate support in the form of a closed volumetric structure in the form of a predominantly parallelepiped allows to significantly expand the frequency range in which the intermediate support can be considered as a solid due to the presence of internal transverse and longitudinal plates, as well as the reinforcement of the closed volumetric structure with stiffeners, which can significantly increase the vibration isolation the effectiveness of a two-stage vibration isolation system of a multi-machine unit. As can be seen from figure 1, the design of the intermediate support in the form of reinforced ribs of the closed volumetric structure and equipping it with internal transverse and longitudinal plates increases the effect of vibration isolation of the multi-machine unit by 10-15 dB. In addition, the use of an intermediate support in the form of a closed volumetric design allows you to realize the effect of sound insulation. This design fulfills both the role of enhancing the vibration-isolating effect and the sound-insulating effect of the vibration-acoustic protection system of a multi-machine unit.

The invention is illustrated by drawings, where figure 2 shows the intermediate support and figure 3 is a General view of a multi-machine unit.

The intermediate support is a closed volumetric structure in the form of a predominantly parallelepiped, which is made of plates 1-6 and reinforced on the inside with stiffeners 7, which are perpendicular to each other on the plane of the plates (figure 2). The intermediate support can also be made in the form of, for example, a truncated pyramid. The inner transverse plate 8 rigidly couples the middle parts of the plates of the opposite walls 1 and 4 in pairs, and the longitudinal plate 9 connects the walls 3 and 5. On the inner side of the plates 1-6 located along the contour, a layer of soundproofing stitching 10 is laid. In turn, the intermediate support with shock absorbing fasteners made up of supporting shock absorbers 11 and persistent shock absorbers 12, is installed on the foundation 13 (Fig.3). The equipment 14 located inside the three-dimensional structure is also mounted on a shock-absorbing mount 15.

The vibrational energy generated by the working mechanisms 15 of the multi-machine unit is transferred to the foundation 13 and to the space surrounding the unit in a many-fold reduced volume as a result of isolation and absorption of the vibrational energy provided by the shock-absorbing fasteners 11, 12 and 15 in combination with an intermediate support and sound-insulating covers 10.

The proposed device of vibration and noise protection of marine power equipment allows to increase the efficiency of vibration and noise insulation of multi-machine units due to the use of a special design of vibration and noise protection of marine power equipment in a two-stage vibration isolation system, which has increased first natural frequencies and soundproof properties, which distinguishes it from prototype.

Claims (1)

A device for vibration and noise protection of marine power equipment, which is an intermediate support of a multi-machine unit for placing its equipment, shock absorbing fasteners and sound insulation, characterized in that the intermediate support is made in the form of a closed volumetric structure in the form of mainly parallelepiped made up of reinforced stiffening plates, on the inner sides of which soundproofing sutures are placed, while the closed volumetric design inside is equipped with on at least two transverse and longitudinal plates rigidly connecting in pairs the middle parts of its opposite walls.

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