FI91093C - Arrangements for lowering the noise level in the maintenance corridor of a paper machine - Google Patents

Description

91093.

Arrangement for reducing the noise level in the paper machine maintenance operation Arrangemang for att sånka ljudnivån i underhållskorridoren av en pappersmaskin 5

The invention relates to an arrangement for reducing the noise level in the operating room of a paper machine, in particular in the vicinity of the wet end of the paper machine and / or the paper post-treatment devices, which arrangement comprises at least one stepping wall, at least one sound-absorbing wall.

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There are increasingly stringent requirements for noise abatement. Especially in the industry, noise pollution has appeared in several different locations in various computer rooms. Paper mills are particularly demanding in terms of noise abatement, as there are several different noise sources in the paper machine room. In the wet end of the paper machine, the wire and press sections in particular cause a lot of noise. In paper mills, various paper finishing equipment, such as slitters and machine calenders, are also bad sources of noise.

With modern high-speed paper machines with a speed of more than 1200 m / min, the noise level at the wet end of the paper machine, especially the wire and press section, is in the data center 20 treatment hall at a distance of about 7 m from the paper machine, up to more than 90 dBA and up to 95 dBA. As the speeds of the paper machine increase, the noise values naturally also increase. The worst sources of noise in the wetland are suction rollers, whose sound pressure levels of more than 100 dBA have been measured at a distance of about 1 m. The press nips in the press section are also bad sources of noise.

25 The sound level, for example at the wet end of a paper machine, depends not only on the noise coming directly from the machine, but also on the reflections from the various surfaces of the paper machine room and the machine. As has been known, efforts have been made to reduce the noise level by installing sound-absorbing material on the walls and ceiling of the paper machine room.

No satisfactory solution has been proposed for reducing the wet noise level of paper machine rooms, although various sound dampers, 30 2 closed hoods and the housing of the wire and / or press section have been tried. The disadvantages of the dampers are the location of the damping, the soiling of the hood and, in both cases, the obstruction caused by the muffler from the control room and the operating room to the machine and the disconnection,

The object of the invention is to provide a solution for reducing the noise level of a paper machine room, in particular its wet end and post-processing equipment, which, however, does not cut off the visual connection from the control points to the machine and does not complicate process maintenance and / or other machine operations.

raised in order to achieve Edellå shown and later in the pååmåarien the invention is mukaiseile jåijestelylle pååasiallisesti characterized, and working åånenvai-15 suppression as the silencer elements are vertical and pitkånomaisia and and working åånenvai-suppression as the silencer elements are disposed in parallel vålimatkan form to suit each other in such a way and working of the damper element vålistå is nåko- and accessible hoitokåytåvåltå paper machine .

20 In this explanatory note, the word "baffle" means a self-supporting element, i.e. a damping element.

The noise-reducing effect of the sound-absorbing wall or baffle wall used in the invention is based not only on the attenuation of sound between the baffles, but also on the elimination of reflections. In addition, for sound sources other than those perpendicular to the direction of the sound wave, there is also a sound attenuation. Using the solution according to the invention, it can be estimated that the noise level in the vicinity of the sound-absorbing wall is 5-8 dB lower than without it. Thus, with the device according to the invention, it seems even possible to lower the noise level (85 dBA) in the therapeutic area in the wet end of 30 paper machines.

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In the arrangement according to the invention, the intervals between the baffle walls of the sound-absorbing wall are dimensioned so that, if necessary, it is possible to pass between the baffles, for example, so that the most common passages have a larger passage and other passages have a smaller passage. The baffle wall can also be movable, in which case the baffle wall can be moved away from the delta of the wire change during maintenance operations, e.g.

The intervals between the baffles provide a continuous face connection and unobstructed access to the paper machine while providing sound attenuation and thus a reduction in noise level.

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The arrangement according to the invention is suitable for use in the sound attenuation of noisy machines of all types of paper mills, in particular in reducing the noise level of the wire and press section of a paper machine as well as post-processing equipment, e.g. slitters and machine calenders. In addition, the baffle transfer arrangements can be implemented in such a way that the baffle wall can be moved, e.g. in front of the drying section and / or behind the headbox of the paper machine.

Depending on the frequency spectrum of the noise, an absorbent material can be used as the sound-absorbing material in the baffle wall and / or the wall can be formed of resonator and / or Helmholtz attenuators.

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In the following, the invention will be described in detail with reference to the figures of the accompanying drawing, to the details of which, however, the invention is not intended to be narrowly limited in any way.

Fig. 1 schematically shows an example of an application of a sound-absorbing wall used in the arrangement according to the invention.

Figures 2A and 2B show schematic examples of baffles, i.e. damping elements, to be used in the arrangement according to the invention.

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Figure 3 shows a schematic example of support rails used in connection with a sound-absorbing wall.

Fig. 4 schematically shows an example of a sound attenuation wall transfer mechanism.

Figures 5A and 5B show schematic examples of transfer arrangements for use with a sound attenuation wall.

Figures 6A and 6B show schematic examples of baffle turnovers.

Figure 7 schematically shows an example of a low frequency sound attenuation element for use in connection with baffles.

Figures 8A and 8B schematically show an arrangement according to the invention fitted to the wire and press section of a paper machine.

Figures 9A-9C schematically show different applications for the arrangement according to the invention.

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Figure 10 schematically shows an arrangement according to the invention fitted in connection with a slitter.

Fig. 1 shows a schematic side view of a sound-absorbing wall 10 comprising self-supporting, vertical and elongate damping elements, i.e. baffles 11. In the arrangement according to the invention, there are several superimposed sound-absorbing walls. The vertical damping elements 11 of the sound attenuation wall 10 are arranged in a row at a distance from each other. The damping elements 11 are formed as a wall structure, e.g. by means of support rails 12,13, of which 30 support rails 13 are at the lower edge of the sound-absorbing wall 10 and the support rail 12 is at the upper edge of the sound-absorbing wall 10. The sound-absorbing wall layers 10j, IO2 are connected to each other e.g.

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5 91093 so that the lower support rail 13 of the next upper layer 102 is attached to the upper support rail 12 of the lower layer 10}. Similarly, several vertical layers 10 can be formed. The sound-absorbing wall 10 is movable on the floor 30 via the wheels 15. The wheels 15 are connected to the lower support rail 13 of the lowest damping wall layer 10j 5.

The thickness S of one damping element 11, i.e. the baffle 11, is about 100-150 mm. The damping elements 11 are spaced apart so that there is room between them and that there is a face-to-face connection between them to the paper machine. The distance L between the damping gate-10 elements 11 is e.g. 500-700 mm. The height H of the sound-absorbing wall 10 is e.g. 2500-3000 mm. The width K of the sound attenuation wall 10 in the longitudinal direction of the machine is e.g. 5000-6000 mm.

The distance L between the damping elements 11 of the sound-absorbing wall 10 is dimensioned in such a way that 15 can pass between them if the machine needs maintenance and also so that there is a direct face-to-face connection to the machine from the control room 11 between the baffles 11. It is also possible to dimension the baffle spacings L in such a way that in the most common passages the distance L between the baffles 11 is larger and elsewhere the distance L is smaller, but still such that, if necessary, the spacer L can accommodate. The total height of the baffle wall 10 via the height H of the wall grooves 20 10j, IO2 is preferably dimensioned such that the height of the arrangement exceeds the height of the machine in the vertical direction. Height H is adjusted by adding sound-absorbing wall layers above.

On the treatment side of the paper machine, 10 sound-absorbing walls 10 are placed in parallel, e.g. 3-5 25 pieces, whereby they extend in the longitudinal direction of the paper machine to the area of the wire and press section.

Figures 2A and 2B schematically show a baffle 11, i.e. a damping element 11, comprising frame structures 21 which are e.g. a U-rail and a perforated plate, rib structure or fiberglass mat protection material 22 protecting and 6 protecting the sound damping material 30 23. but does not impair its sound-absorbing properties. The width P of the Baffel 11 is e.g. 800-1200 mm.

The damping material 23 is selected so as to achieve the desired sound damping properties. The damping material can be, for example, based on absorbent damping, in which case, for example, with 100 mm thick mineral wool the absorption properties are as follows: frequency Hz 125 250 500 1000 2000 4000 10 absorption coefficient 0.50 0.78 0.95 0.90 0.88 0.90 0.90.

Based on the measurements (the measurement has been performed 7 m from the press section), the sound level of the wet end of the paper machine is at its highest in the frequency range of 500 Hz to 4 kHz. In these areas, the sound absorption of the material is practically 100% achieved with the material described above. For example, in the damping element 11 the absorption surface is 3 m high and for the 1 m deep damping element 6 m2, i.e. for a wall with a height of 9 m, a width of 6 m and a baffle spacing of L 0.5 m (11 elements x 3 layers = 33), the absorption surface is 6 x 33 or - 200 m2.

20 Instead of an abscess damping material 23, a plate resonator or Helmholtz sound absorbers can also be used in the baffles 11, which will be described in more detail in connection with Fig. 7.

Figure 3 schematically shows the formation of the damping wall 10 by means of damping elements 11 and support rails 12,13. The damping elements 11 are fastened to the support rails 12,13 at a suitable distance from their upper and lower corners. The damping elements 11 are arranged in a row at a distance from one another next to each other so that the desired width K of the damping wall 10 is achieved.

Figure 4 shows a transfer mechanism in the damping wall 10. Pulls 15 or other I! Are connected to the lower part of the damping wall 10 on the treatment side of the paper machine. 7 91093 correspond to the transfer members 15. The wheels 15 run, for example, in grooves made in the floor 30 of the paper machine room (Figs. 5A and 5B). The quench 10 bar top section is attached to the frame beam 36 which extends transversely across the paper machine and is supported siirtoeli-men 37 to the kayttopuolen 35 of the beam protrusion 39 into the groove 38. The transverse five support members 36 are placed in such a way and working the ordinary course of normal production mode eivåt so in the wire and press section ylåpuolella at critical points. Preferably, the frame beams 36 are located at locations where there is no exposed paper web under the beam. It is also possible to use existing paper machine frame structures and maintenance bridges to support the 10 sound-absorbing walls.

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Figures 5A and 5B show schematic partial views of the transfer arrangements of the damping wall 10. Fig. 5A shows rail wheels 15 attached to support rails 13, which are adapted to move in rails 32 arranged in grooves 31 made in the floor 30.

Fig. 5B shows an application example in which the sound-absorbing wall 10 is transmitted by an electric motor 40 or e.g. a hydraulic motor or a similar transfer member, which electric motor 40 transmits the movement e.g. The sound attenuation wall 10 may also be without transfer members and devices.

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According to Figures 6A and 6B, the damping elements or baffles 11 of the sound-absorbing wall 10 can be formed as a sound-absorbing wall 10 so that they can, for example, be manually inverted like a vertical curtain so that they are completely closed in position A, in situations where

25 fully open for direct connection. The baffles 11 can be rotated from position A to position B or to a position between these positions. In position B, the baffles 11 form a closed sound-absorbing wall 10. In the embodiments according to Fig. 6A, the gap between the open baffles 11 in position A becomes quite large, whereby the sound attenuation decreases, Fig. 6B shows an embodiment 10, in which position A more effective sound attenuation is achieved compared to the application example according to Fig. 6A.

Fig. 7 shows an application example of a baffle 11 in which a reactive silencer structure 5 is used. Absorbent mufflers operate mainly at higher frequencies and have a maximum attenuation at about 1000 Hz, while reactive mufflers, mainly based on different resonator structures, operate most efficiently at low frequencies at 200-200 and their maximum attenuation is tuned. In the figure, the baffle 11 comprises trays 53 and 10 comprising two tray elements 50. In resonator or membrane dampers, a plate 51 is used, in which the oscillation of the plate converts the sound energy into thermal energy. In the Helm-Holz resonator, the resonator is formed by an air space which is in communication with the outside air through an opening 54 in the plate 52. The air plug in the opening 54 forms a mass which resonates with the spring force forming the air trapped in the cavity. The baffle 11 shown in Fig. 15 covers the membrane plate 51 and, if removed, a Helmholz damper is available and again, when removing the plate 52 with openings 54, it is a plate resonator.

Fig. 8A shows a schematic cross-section of a sound-absorbing wall 10 fitted in connection with a paper machine 100. On the treatment side, there is a damping wall 10, which can be moved by means of wheels 15. Vaimennusseinan påålle 10 is disposed forming an angle lisåvaimennusseinåmå to 14, 36 secured to the frame beam is supported vaimennusseinå kåyttopuolen over the supporting structures of the paper machine 35.39.

Fig. 8B is a top view of an application example shown in Fig. 8A, in which the sound-absorbing wall 10 comprises baffles 11 and is supported on the use side by means of frame beams 36. Reference numeral 103 denotes a headbox of a paper machine, which is followed in the direction of travel of the paper web W by a wire section 101 and a press section 102.

The distance E of the sound attenuation wall 10 from the paper machine is e.g. 3 m and the distance Ej from the wall, i.e. the width of the treatment hall is e.g. 6 m.

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Fig. 9A shows a schematic side view of a paper machine 100, in which the headbox 103 is followed by a wire section 101, further followed by a press section 102, followed by a drying section 104 (sound and heat insulated) encapsulated in an absorbent material.

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Fig. 9B is a schematic side view of sound attenuation walls 10 according to the invention fitted to a paper machine, which in the example of the figure protect the wet end of the paper machine by covering the longitudinal area of the headbox 103, the wire section 101 and the press section 102. The drying section 104 is encased in an absorbent material 80, and in addition 10, an absorbent material 81 is placed on the ceiling of the paper machine room to provide additional sound attenuation.

Fig. 9C shows an application example in which one of the sound-absorbing walls is moved in front of the drying section 104. When the sound attenuation walls 10 are moved in front of the drying section 104 and the lift doors 104 (not shown) of the drying section 104 are open, the sound attenuation wall 10 attenuates the noise propagating from the lift doors.

Fig. 10 shows an application example in which the slitter 105 is encased in a sound-absorbing or baffle-wall 10. The passages of the paper web W are naturally left free so that the paper web can pass.

The invention has been described above only with reference to some of its preferred application examples, the details of which, however, are not intended to limit the invention in any way, but many modifications and variations are possible within the scope of the inventive idea defined in the following claims.

Claims (10)

An arrangement for lowering the noise level in the maintenance corridor of a paper machine, in particular in the proximity of the wet spirit of the paper machine and / or the paper finishing apparatus, which arrangement comprises at least one sound attenuation wall (10), which attenuates sound attenuation (10) (11) and standing structures (12,13) for the dimming elements (11), characterized in that the dipping elements (11) in the light dimming are wavy (10) are vertical and elongated and that the dipping elements (11) in the sound dipping wave (10) are positioned side by side at a distance (L) from each other in such a way that there is sight and walking connection from the maintenance corridor to the paper machine between the dipping elements (11). 2. Arrangement according to claim 1, characterized in that the sound attenuation wave (10) comprises displacement means (15) for displacing the sound attenuation wave (10) in the longitudinal direction of the paper machine. 3. Arrangement according to claim 1, characterized in that the damping elements (11) are absorbent damping elements and comprise a sound damping material 20 (23), body structures (21) and a protective member (22) which protects the sound damping material (23). 4. Arrangement according to claim 1, characterized in that the dimming elements (11) are the dimming element based on reactive sound attenuation (FIG. 7). 25 5. Arrangement according to any one of claims 1-3, characterized in that the distance (L) between the damping elements (11) in the sound damping wave (10) is 500-700 mm. II 91093 Arrangement according to one of the preceding claims, characterized in that the arrangement comprises at least two side-by-side sound attenuation walls (10) in the longitudinal direction of the paper machine. Arrangement according to any of the preceding claims, characterized in that the arrangement comprises at least two sound damping walls (10) on top of each other in such a way that the total height of the arrangement corresponds at least to the height of the paper machine at the sound damping wave (10). 1 Arrangement according to one of the preceding claims, characterized in that the sound attenuation wave (10) is supported by an overhead beam (36) extending over the machine in the transverse direction of the machine, which was supported by a displacement member (37) on structures. on the operating side of the paper machine and / or on structures on a beam (35) located on the operating side. 15 Arrangement according to one of the preceding claims, characterized in that the displacement means (15) for the sound attenuation wave (10) are wheels which are arranged displaceable by means of a functional means (40) e.g. an electric motor or a hydraulic motor. 20 Arrangement according to one of the claims, characterized in that the sound attenuation wave (10) is arranged displaceable with the help of a hall crane.