RU2583441C1 - Kochetov device for acoustic protection of operator - Google Patents

Abstract

FIELD: acoustics.

SUBSTANCE: invention relates to means of safety of operation of operators in emergency situations, particularly at high levels of noise. Device for acoustic protection of operator comprises operator workstation, equipped with means of reducing noise. Operator workstation is located between acoustic shields, which protect operator from direct sound propagating from vibration active equipment. Above working zone there is suspended ceiling, arranged in upper zone of room. To reduce sound vibration operator workstation is equipped with floor on elastic base providing two staged protection of operator. Also there is rocker acoustic absorber, which consists of rigid frame suspended by hooks on ropes to building ceiling with sound absorbing material wrapped in mesh caproic fabric located inside frame. Expanded stretching steel sheet is fixed to frame. Wall noise absorbing panel installed on cover consists of sound-absorbing plate-type sound insulating material of “Shumanet-ECO” type (50 mm); plaster-fiber sheet 12.5 mm; sheet brand 12.5 mm; profile of “Vibronet PN” type 100/40; gasket of “Vibrostek-M” type (2 layers); sealant of “Vibrosil” type. “Shumanet-BM” type plates are used as effective middle layer in sound-insulating frame partitions or lining from sheets of GKL/GVL, chip boards, plywood, as well as in systems of acoustic perforated screens or suspended ceilings. In assembly of sandwich panels flat gasket “VIBROSTEK-M” is used, which is laid in two layers in places of its support on floor, as well as at contact points of panels with side walls and ceiling. When mounting “Vibrosil” type sealant is used: one-component vibration isolating silicone sealant for sealing of joints and connections in special sound insulating structures. As vibration isolating wall fasteners “VIBROFLEX” type shock-absorbing device is used for solving tasks of reducing noise and vibrations transfer in premises of any type and purpose. For mounting to vertical enclosing structures wall versions of ER type fasteners, which is microporous polyurethane elastomer, especially for solving tasks of sound and vibration insulation. Acoustic noise absorbing panel is made in form of sound-absorbing structure consisting of rigid and perforated walls, between which multilayer sound absorbing element is placed made in form of five layers, two of which, adjacent to walls are sound-absorbing layers from materials of different density, while three central layers are combined. Axial layer is made sound absorbing, and two symmetrical adjoining layers are made from sound reflecting material of complex profile composed of evenly distributed hollow tetrahedrons. Each of perforated walls has following perforation parameters: hole diameter is 3÷7 mm, perforation percentage is 10÷15 %. Sound-absorbing material used is in the form of Rockwool mineral wool boards on a basalt base or URSA mineral wool or P-75 basalt wool or glass wool lined with glass felt. Sound absorbing element on its entire surface is lined with an acoustically transparent material, for example, EZ-100 glass cloth or Poviden polymer.

EFFECT: invention allows to improve efficiency of noise suppression.

1 cl, 7 dwg, 2 tbl

Description

The invention relates to safety equipment for operators in emergency situations, in particular at elevated noise levels.

The closest technical solution to the technical nature and the achieved result is acoustic protection according to the patent of the Russian Federation No. 139312 [prototype] as a way of acoustic protection for the operator, namely, that the operator’s workplace is equipped with noise reduction means.

The disadvantage of the technical solution adopted as a prototype is the relatively low efficiency of sound attenuation due to the relatively low coefficient of sound absorption.

The technical result is an increase in the efficiency of sound attenuation.

This is achieved by the fact that in the operator’s acoustic protection device containing the operator’s workplace located between the acoustic screens and the acoustic suspended ceiling, the operator’s workplace is equipped with a floor on an elastic base in the upper area of the room to reduce sound vibration, while the operator performs two-stage vibration protection.

In FIG. 1 shows a general view of an apparatus for acoustic protection of an operator; FIG. 2 - floor structure of the premises on an elastic base, in FIG. 3 shows a shock-absorbing structure for installing a wall panel; FIG. 4 shows a structure of a wall sound-absorbing panel mounted on a floor, in FIG. 5 is a design of the rocker sound absorbers, in FIG. 6 is a graph of sound absorption efficiency of applied panels; FIG. 7 is a variant of the acoustic wall panel diagram.

The device for acoustic protection of the operator (Fig. 1) contains the building frame made in the form of an elastic base 1, which is the floor of the room (Fig. 2), heat and sound insulating barriers 2, rigidly connected to the columns 3, which in turn are connected to the metal structure 4, for example in the form of a farm. An acoustic suspended ceiling 5 is placed in the zone of the trusses 4 and is made in the form of rocker sound absorbers installed with a certain pitch, the lower part of which protrudes from the lower part of the trusses 4 towards the base 1. Acoustic wall panels 6 are mounted on fences 2 on a shock-absorbing structure for installing a wall panel Fig. 3). On the elastic base 1 of the room installed vibroacoustic equipment 7 and 8 with different spectral characteristics of sound power levels. The operator’s workstation 15, including control panels 16 and 17 of equipment 7 and 8, is located between the acoustic screens 9 and 11, and in one of them, for example, the 9th, a soundproof inspection hatch 10 is made to control visualization of observation of the process. The building frame is closed from above with a soundproof coating 12, which also functions as a roof, in which there are vertical 13 and inclined 14 window openings in the form of vacuum soundproof glass packets.

The floor structure on an elastic base (Fig. 2) contains a mounting plate 18 made of concrete reinforced with vibration damping material, which is installed on the base plate 19 of the floor with cavities 20 through layers of vibration damping material 21 and waterproofing material 22 installed with a gap relative to the bearing walls 23 production premises. In order to ensure effective vibration isolation of the mounting plate 18 in all directions, the layers of the vibration damping material 21 and the waterproofing material 22 are made with a flange that is closely adjacent to the supporting structures of the walls 7 and the base supporting plate 19 of the floor. To increase the efficiency of sound insulation and sound absorption in the workshops located under the floor, the cavities 20 are filled with vibration damping material, for example, foamed polymer, or polyethylene, or polypropylene.

The floor structure on an elastic base works as follows. When installing vibroactive equipment 7 and 8 on plate 18, two-stage vibration protection occurs due to vibration damping inclusions in the mass of plate 18 itself, and also due to a layer of vibration damping material 21, which can be used as: Vibrosil needle-punched mats based on silica or aluminoborosilicate fiber, a material made of solid vibration-damping materials, such as plastic, from soundproofing plates based on glass staple fiber of the Shumostop type with a material density of 60 ÷ 80 kg / m ³ .

The transition of sound energy into thermal energy (dissipation, energy dissipation) occurs in the pores of sound-absorbing material, which is a 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 walls of the mouth itself, having the form branched pore network of sound-absorbing material. Moreover, needle-punched mats consist of fibers having a diameter not lower than the maximum permissible hygienic value, do not contain carcinogenic asbestos and ceramic fibers, and such harmful binders as phenol are not included in their composition. Therefore, with confidence they can be attributed to the class of heat and sound insulating materials that meet high hygienic and fire safety requirements. We add that fiberglass materials have low thermal conductivity, are not influenced by steam, oil, water, and have high temperature stability.

Acoustic wall panels 6 can be made in the form of slabs of rockwool basalt mineral wool, or URSA mineral wool, or P-75 basalt wool, or glass wool lined with glass wool, or foamed polymer, such as polyethylene or polypropylene, and the sound-absorbing element over its entire surface is lined with an acoustically transparent material, such as fiberglass type EZ-100 or polymer type "Poviden."

A possible embodiment of the acoustic wall panel 6 in the form of a sound-absorbing structure (Fig. 7), which is made in the form of a smooth, rigid wall 30 and a perforated wall 36, between which there is a multilayer sound-absorbing element made in the form of five layers, two of which are adjacent to walls 30 and 36, are sound-absorbing layers 31 and 35 of materials of different densities, and the three central layers 32, 33, 34 are combined, and the axial layer 33 is made sound-absorbing, and two symmetrically located and adjacent their layers 32 and 34 to it are made of sound-reflecting material, a complex profile consisting of uniformly distributed hollow tetrahedrons, which allow reflecting sound waves incident in all directions. The perforated wall 36 has the following perforation parameters: the diameter of the holes 3 ÷ 7 mm, the percentage of perforation 10% ÷ 15%, and the shape of the holes can be made in the form of holes of a round, triangular, square, rectangular or diamond shape, while in the case of non-circular holes as the conditional diameter should be considered the maximum diameter of the circle inscribed in the polygon.

Each of the walls 30 and 36 can be made of structural materials with a layer of soft vibration-damping material, for example, VD-17 mastic or “Gerlen-D” type material applied to one or two sides of the material, and the ratio between the thicknesses of the material and vibration-damping coating lies in the optimal range of values: 1 / (2.5 ... 3.5).

Each of the walls 30 and 36 can be made of stainless steel or galvanized sheet with a thickness of 0.7 mm with a protective and decorative polymer coating such as Pural 50 μm thick or Polyester 25 μm thick, or an aluminum sheet 1.0 mm thick and coating thickness 25 microns. The perforation coefficient of perforated sheets is taken to be equal to or more than 0.25.

Each of the walls 30 and 36 can be made of solid, decorative vibration damping materials, such as plastic compounds such as Agate, Anti-Vibrate, Shvim, and the inner surface of the perforated surface facing the sound-absorbing structure is lined with an acoustically transparent material, such as fiberglass type EZ-100 or a polymer of the “poviden” type, or nonwoven materials, for example, “lutrasil”.

Sound-absorbing design works as follows.

Sound energy from equipment located in the room or another object that emits intense noise from the object, passing through the perforated wall 36, enters the layer 35 of soft sound-absorbing material, and then encounters layers 34, 33 and 32 of complex reflective sound-reflecting material, respectively consisting of uniformly distributed hollow tetrahedra, which allow reflecting sound waves incident in all directions, but part of the sound energy passes through layers 32 and 34 of sound-reflecting material, and interactions interacts with the axial layer 33 of sound-absorbing material, where the final dissipation of sound energy occurs.

Layers 31 and 35 of soft sound-absorbing material of different densities can be made, for example, of basalt or glass fiber). 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 a 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 frequency of excitation on the neck wall, which has the form of a branched sound absorber pore network. In addition, there is air friction on the 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.

A device for acoustic protection of the operator operates as follows.

The operator’s workplace 15 is placed between the acoustic screens 9 and 11 and protects the operator from direct sound that is spreading from the vibroactive equipment 7 and 8. In order to increase the protection against reflected sound waves above the work area (workplace), an acoustic suspended ceiling 5 is installed, located in the upper area of the room (farm zone 4). It reduces the levels of sound waves emanating from equipment 7 and 8, due to the multiple reflection of sound waves from the rocker sound absorbers. To reduce sound vibration, the operator’s workplace is equipped with a floor on an elastic base. When installing vibroactive equipment 7 and 8 on plate 18, two-stage vibration protection occurs due to vibration damping inclusions in the mass of plate 18 itself, and also due to a layer of vibration damping material 21, which can be used as: Vibrosil needle-punched mats based on silica or aluminoborosilicate fiber, a material made of solid vibration-damping materials, such as plastic, from soundproofing plates based on glass staple fiber of the Shumostop type with a material density of 60 ÷ 80 kg / m ³ .

Indoors, where the area of open brick, plaster, concrete, tile, glass, metal is large, a long echo is always heard. If in such rooms there are several sources of sound (people's conversation, music, industrial noises), then direct sound is superimposed on its loud first reflections, which leads to speech illegibility and an increased noise level in the room. To reduce or correct the reverberation time of premises, sound-absorbing materials and structures (sound absorbers) are used in its decoration.

From an acoustic point of view, sound absorbers can be divided into the following groups: porous (including fibrous); porous with perforated screens; resonant; layered structures; piece or volume.

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, slag, 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

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 Lutrasil.

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.

Recall that the sound absorption coefficient α is equal to the ratio of the energy of the air vibrations 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. Fibrous and porous materials are used mainly to improve acoustic performance in cinemas, theaters, concert halls, studios, and auditoriums. In addition, they are used to reduce noise in kindergartens, schools, hospitals, restaurants, offices, retail halls, lobbies, waiting rooms, industrial premises.

The operator’s workstation 15 is reliably protected both from the acoustic load on the operator and from mechanical factors of the production environment, such as, for example, shavings in the workshop or moving parts of equipment.

Sound energy from equipment 7 and 8 located in the room, passing through the perforated wall of the acoustic wall panels 6, enters the layers of sound-absorbing material (which can be either soft, such as basalt or glass fiber, or hard, such as shell rock). 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. The perforation coefficient of the perforated wall is taken to be equal to or more than 0.25. To prevent the eruption of a soft sound absorber, a fiberglass fabric, for example, type EZ-100, is located between the sound absorber and the perforated wall. In this case, the acoustic suspended ceiling 5, located in the upper zone of the room (farms zone 4), reduces the levels of sound waves emanating from equipment 7 and 8, and the operator’s workstation 15, located between the acoustic screens 9 and 11, is reliably protected as from acoustic load on the operator, and on the mechanical factors of the production environment, such as, for example, shavings floating in the workshop or moving parts of the equipment.

In FIG. 4 shows the design of a wall sound-absorbing panel mounted on the ceiling, which consists of 24 - sound-absorbing plate of the Schumanet-ECO type (50 mm); 25 - sheet gypsum fiber 12.5 mm; 26 - gypsum plasterboard sheet 12.5 mm; 27 - profile type Vibronet PN 100/40; 28 - gasket type Vibrostek-M (2 layers); 29 - sealant type Vibrosil.

Sound-absorbing plate like Schumanet-ECO or SHUMANET-BM

Sound absorbing mineral wool board. SHUMANET-BM slabs are used as an effective middle layer in the design of soundproofing frame partitions or claddings of sheets GKL / GVL, chipboard, plywood, as well as in systems of acoustic perforated screens or suspended ceilings. Composition: hydrophobized mineral wool slab based on basalt rocks. Dimensions: Plate length: 1000 mm. Plate width: 600 mm. Plate thickness: 50 mm. Physical characteristics: bulk density: 40 kg / m ³ . The number of plates in the package: 4 pcs. Amount of packaging: 2.4 m ² . Packing volume: 0.12 m3. Package weight: 5.5 kg.

table 2 Acoustic Test Results frequency Hz one hundred 125 160 200 250 320 400 500 630 SHUMANET-BM plates without rel 0.14 0.26 0.40 0.56 0.67 0.82 1.00 1.00 1.00 SHUMANET-BM plates with a ratio of 50 mm from a hard surface 0.45 0.54 0.68 0.76 0.92 0.96 0.99 1.00 1.00 frequency Hz 800 1000 1250 1600 2000 2500 3200 4000 5000 SHUMANET-BM plates without rel 1.00 1.00 1.00 1.00 0.99 0.99 0.93 0.90 0.90 SHUMANET-BM plates with a ratio of 50 mm from a hard surface 1.00 1.00 0.98 0.95 0.90 0.88 0.85 0.83 0.80

Vibrostek-M is a tape packed from a soundproof fiberglass packed in a roll. Structural noise isolation is ensured by the elastic properties of the porous-fibrous structure of the material. This determines the stable physical and mechanical characteristics of the gasket under static and dynamic loads, as well as the preservation of the declared acoustic properties over a long service life.

VIBROSTEK-M is used as a cushioning material in building structures during the installation of a panel system, frame soundproofing partitions and cladding, as well as wooden floors and ceilings. Composition: multilayer soundproof fiberglass LB300, based on fiberglass type “C”. Vibroacoustic characteristics: dynamic modulus of elasticity u: 0.18 MPa at a load of 2 kPa, 0.35 MPa at a load of 5 kPa. Relative compression ratio units: 0.25 at a load of 2 kPa, 0.35 at a load of 5 kPa.

When installing sandwich panels, the VIBROSTEK-M strip gasket is laid in two layers at the points of their support on the floor, as well as at the places where the panels come in contact with the side walls and the ceiling. When mounting frame partitions and claddings, the VIBROSTEK-M material is used between the frame profiles (fasteners) and the supporting building structures. VIBROSTEK-M material tapes are also used in the places where the cladding sheets of the partition (cladding) are adjacent to other building structures.

Vibrosil type sealant: VIBROSIL, a one-component vibration-isolating silicone sealant, is designed to seal joints and joints in special soundproof structures. Sealant provides high vibration isolation of joints between building structures. Reduces the propagation of structural noise over them and thereby enhances their own sound insulation. It is used to fill joints in the construction of soundproof (floating) floors, panel systems, frame soundproofing partitions and claddings. Composition: sealant is made on the basis of silicone resins and silicon-containing modifying additives.

VIBROFLEX vibration-isolating wall mounts (Fig. 3) are a shock-absorbing device for solving problems of reducing noise and transmitting vibrations in rooms of any type and purpose. For mounting to vertical enclosing structures, wall versions of EP type fasteners have been developed. Scope: wall mounts are used for soundproofing wall cladding, vibration isolation of pipelines of engineering networks, ventilation ducts, suspended engineering equipment and other vibration-emitting units. Composition: the design is based on the unique Sylomer material - it is a microporous polyurethane elastomer specially developed for solving problems of sound and vibration isolation.

The composite rocker sound absorber (Fig. 5) consists of at least two parts of a rigid frame, pulled together by clamps and suspended by hooks on rails (not shown in the drawing) or directly attached to the ceiling of a production building. Inside the frame is a sound-absorbing material wrapped in a mesh nylon fabric or fiberglass. In some cases, expanded glass sheet (not shown) may be attached over the glass fabric 3 to the frame. The frame can be made in the form of a rectangular parallelepiped with dimensions of d × h × b ribs, the ratio of which lies in the optimal range of d: h: b = 2: 1: 0.5 or a cube with k × L rib size, where min L = 100 mm; k is the coefficient of proportionality, lying in the range from 1 to 10 in steps of 2. Inside the wings, cavities not filled with sound-absorbing material can be made. For all suspension schemes, the optimal size ratios must be observed: m - from the point of suspension of the frame on the guide to the ceiling and c - the distance between the axes of adjacent frames, and the ratio of these sizes should be in the optimal range of values: m: c = 1: 1 ... 0, 5: 1. The filling is carried out with a sound-absorbing non-combustible material (for example, vinipore, fiberglass) with a protective layer of fiberglass, preventing the sound absorber from falling out.

Rocker sound absorber works as follows.

Sound waves propagating in the production room interact with cavities filled with sound absorber. Sound absorption at low and medium frequencies occurs due to the acoustic effect constructed on the principle of Helmholtz resonators formed by cavities. Different volumes of resonant cavities are used to suppress sound vibrations in the required sound frequency range, as a rule large volumes to suppress noise in the low-frequency range, and small ones in the medium and high frequencies.

The proposed method of acoustic protection is an effective way to combat industrial noise.

Claims (1)

A device for acoustic protection of an operator, comprising an operator’s workstation equipped with noise reduction means, an operator’s workplace is located between acoustic screens that protect the operator from direct sound propagating from vibroactive equipment, and an acoustic suspended ceiling is installed above the workspace located in the upper area of the room and to reduce sound vibration, the operator’s workplace is equipped with a floor on an elastic base, which provides two-stage vibration protection of the operator, as well as a rocker absorber is provided, which consists of a rigid frame suspended by hooks on cables to the building ceiling with sound-absorbing material located inside the frame wrapped in mesh nylon fabric, and expanded metal sheet is attached to the frame, and the frame is made in the form of a rectangular parallelepiped with edge sizes d × h × b, the ratio of which lies in the optimal range of d: h: b = 2: 1: 0.5 or a cube with the edge size k × L, where min L = 100 mm; k is a proportionality coefficient ranging from 1 to 10 in increments of 2, and for all suspension schemes, the optimal size ratios must be observed: m - from the point of suspension of the frame on the guide to the ceiling and c - the distance between the axes of adjacent frames, and the ratio of these sizes should be in the optimal range of values: m: c = 1: 1 ... 0.5: 1, use the design of the wall sound-absorbing panel mounted on the ceiling, which consists of a sound-absorbing plate of the Schumanet-ECO type (50 mm); gypsum sheet 12.5 mm; gypsum plasterboard sheet 12.5 mm; profile type Vibronet PN 100/40; gaskets like Vibrostek-M (2 layers); Vibrosil type sealant, using SHUMANET-BM boards as an effective middle layer in the design of soundproofing frame partitions or claddings of sheets GKL / GVL, chipboard, plywood, as well as in systems of acoustic perforated screens or suspended ceilings, and when installing sandwich panels use the VIBROSTEK-M strip gasket, which is laid in two layers at the places of their support on the floor, as well as at the places where the panels come into contact with the side walls and the ceiling; during installation, Vibrosil type sealant is used: one-component vibration-insulating silicone sealant for sealing joints and joints in special soundproofing structures, and VIBROFLEKS as vibration-isolating wall mounts - a shock-absorbing device for solving problems to reduce noise and transmit vibrations in rooms of any type and purpose, and use for mounting to vertical enclosing structures wall mounting options like EP - microporous polyurethane elastomer, especially for solving problems of sound and vibration isolation, characterized in that the acoustics The sound-absorbing panel is made in the form of a sound-absorbing structure consisting of a rigid and perforated walls, between which there is a multilayer sound-absorbing element made in the form of five layers, two of which adjacent to the walls are sound-absorbing layers of materials of different densities, and the three central layers are combined, and the axial layer is made sound-absorbing, and two symmetrically located adjacent layers are made of sound-reflecting material of a complex profile, consisting of uniformly distributed hollow tetrahedrons, each of the perforated walls has the following perforation parameters: hole diameter 3 ÷ 7 mm, perforation percentage 10% ÷ 15%, and rockwool basalt-based mineral wool boards are used as sound-absorbing material, or mineral wool of the URSA type, or basalt wool of the P-75 type, or glass wool lined with glass wool, and the sound-absorbing element over its entire surface is lined with an acoustically transparent material, such as fiberglass type E -100 or polymer type "poviden".

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