EP1624122B2 - Arrangement of a sound absorbing element attached to the inner side of an external wall of a building and method of its manufacture. - Google Patents

Description

The invention relates to an arrangement of an applied on the inside of a building exterior wall sound-absorbing element and a method for its preparation.

Sound-absorbing elements which can be attached to walls or ceilings play an important role in structural engineering for damping environmental noise and influencing the frequency response of rooms. In particular, with sound-absorbing elements, the reverberation time of rooms can be shortened and the formation of resonance sound, which is caused by unfavorable dimensioning or geometry of the space caused standing waves, can be reduced. The attenuation of frequencies below 100 Hz is often associated with considerable effort or previously had an unsatisfactory architectural appearance.

Sound-absorbing elements according to the prior art are often constructed as plate resonators, such as in the EP 0 811 097 described. The disclosed in this document Plattenresonator for broadband attenuation of rooms includes a thin front panel made of metal, which is excitable at sound waves below 125 Hz for resonant oscillation, also a back plate made of an elastomer, and a full-surface solid connection between the front panel and back plate, for example by double-sided adhesive tape and, finally, a boundary which is closed on all sides by the back plate and does not hinder lateral sound entry into the back plate. This plate resonator can be attached to the ceiling or wall using edge fasteners.

From the document FR 2,841,580 disclosing all features of the preamble of claim 1, an arrangement of a sound absorbing member applied to a ceiling or wall is known. The element has a construction of a lower layer with cellulose and a surface layer connected to the lower layer, which has a higher specific gravity than the lower layer.

In the document DE 295 17 568 U1 describes a prefabricated insulation board made of cellulose, which serves as a plaster base to attach to a wall and apply a mineral plaster layer on it.

The document US 2,094,839 discloses a conveyor having a material supply unit adapted to receive cellulosic material, a metering unit for metering the material supplied, and a fan for delivering the metered material to a spray head, the metering unit comprising a screw conveyor for continuously conveying the cellulosic material and the fan connected to the output of the screw conveyor.

A disadvantage of this known sound-absorbing element is the fact that it can develop satisfactory effect only in small rooms, if one does not accept that the sound-absorbing element is sized as large as the wall or ceiling to which it is attached. Since the latter is hardly feasible for visual and practical reasons, the sound-absorbing element can only "selectively" act in space. Another disadvantage of the known sound-absorbing element is that its attachment has to be done very carefully and optionally with the use of vibration damping elements so as not to become the cause of resonant vibrations that can lead to unpleasant noise. In the attachment of the known sound-absorbing elements to the wall or ceiling, there is also the risk of the formation of sound bridges by sound impinging on the sound-absorbing element via the fasteners is forwarded to the masonry. Finally, in the known sound-absorbing element also has a problem that it acts as an internal insulation without vapor barrier in the case of application to the inside of a building exterior wall and can lead to condensate formation at the boundary layer to the masonry due to dew point shift. This can lead to mold growth. The above-mentioned moisture problems become greater, the greater the area proportion of the known sound-absorbing elements in comparison to the sum of the wall and ceiling surfaces.

The present invention has for its object to solve the problems occurring in the known sound-absorbing elements.

The invention achieves this object by providing an arrangement of a sound-absorbing element with the characterizing features of claim 1.

Advantageous embodiments and modifications of the invention are set forth in the subclaims.

The inventive arrangement of an applied on the inside of a building exterior wall, sound-absorbing element with the structure of the element of a lower layer with cellulose as the main component and a fully connected to the lower layer upper layer of a material having a higher specific gravity than the lower layer acts as broadband Plate resonator, which absorbs sound over a large area, wherein the flexibility of the cellulosic material of the lower layer and the elastic mass of the upper layer cooperate to attenuate sound broadband. The topsheet is elastic to some extent. The sound-absorbing element can be applied both on flat and on uneven or curved surfaces.

It can be mentioned that it is known that an exposed cellulose insulation layer sprayed on walls and ceilings for thermal insulation also has an acoustic damping effect, which, however, is only noticeable in higher frequency ranges. However, a broadband sound absorption behavior over the entire construction acoustically relevant frequency range can not be achieved with the known exposed cellulose insulating layers.

In addition to the excellent acoustic absorption properties, the sound-absorbing element according to the invention has the great advantage that it can extend over the entire surface of walls or ceilings of rooms and thus neither distracting works in architectural terms nor displaced space. The sound-absorbing element according to the invention is characterized by high sorption capacity, wherein the absorbed moisture is released back to the ambient air, so that condensation is avoided.

In the sound-absorbing element according to the invention, its upper layer is formed as a plaster layer, with mineral plasters being preferred. Alternatively, the top layer may be formed of structural panels such as wood, gypsum or plasterboard. The In these cases, sound-absorbing element presents itself as a wall which can be treated like ordinary walls, for example by applying a paint.

For precise adjustment of the frequency response of the sound-absorbing element according to the invention, i. in which frequency range it develops its sound-absorbing effect is provided in a development of the invention to provide the upper layer with sound passages. By number, dimensioning and shape of the sound passages, the frequency response can be set exactly. Alternatively or additionally, to adjust the frequency response, the upper layer can be subdivided into regions which are decoupled from each other in terms of vibration.

Furthermore, it can be provided to adjust the frequency response of the sound-absorbing element in addition to varying the thickness and / or the binder addition by changing the density of the lower layer by using screened in a certain grading cellulose. The grading curve is determined by the sequential arrangement of sieves of different mesh size to which the cellulose to be screened is fed. By changing the grinding process in the production of the cellulose flakes, the fiber length can be varied so that the amount of cellulose particles passing through the respective sieve sets is within the desired range.

For good adhesion of the cellulose particles, binders may be added to the underlayer when applied. Preferably, the dynamic stiffness of the underlayer is adjusted by the amount and type of binders added. The dynamic stiffness of the lower layer in turn influences the frequency response of the sound-absorbing element. The added, preferably organic, binders comprise either powdered, water-activatable binders, or liquid adhesives, such as latex adhesive or polyvinylacetate-based adhesive.

Since cellulose is an organic material that can be attacked by mold under unfavorable climatic conditions, it is provided in a development of the invention to mix fungicides to the lower layer. Likewise, to achieve fire-retardant properties fire retardants, such as borates, are added to the undercoat.

According to the invention, there is an adhesive, full-surface connection between the lower layer and the upper layer. This full-surface bonding can be assisted by providing a tie layer with good adhesion between the backsheet and the topsheet.

In order to prevent the occurrence of sound bridges due to abutment of the sound-absorbing element and adjacent walls, or the mechanical vibration capability of the upper layer is impaired, it is provided in one embodiment of the invention that at least partially sound decoupling elements are arranged at the peripheral edges. Foam tapes or Elastomerbänder perform well in this regard. Likewise, the aforementioned sound decoupling elements can be used to divide the upper layer into a plurality of mutually vibrationally decoupled areas.

The invention also provides a method for producing an arrangement of a sound-absorbing element on a wall, characterized by the features of claim 9.

The inventive method is characterized by ease of use and great flexibility and is very well feasible even on uneven ground.

The cellulose particles of the underlayer are applied by spraying on the wall, wherein in one embodiment of the invention, the cellulose particles are mixed prior to application with an adhesive foam, which also serves as a transport material and provides bond strength among the cellulose particles. Alternatively, the cellulose particles are mixed with water before being applied to the wall.

In order to ensure a reliable adhesion between the wall and the lower layer of the sound-absorbing element according to the invention, under some circumstances it may be necessary to improve the adhesion before applying the lower layer Priming layer, in particular binder layer to apply to the wall. It is also possible to form the underlayer by producing underlayer panels in factories by placing the binder-added cellulose in frames and allowing it to dry, then removing the panels from the frames and transporting them to the site where they are cemented using an adhesive or the like. attached to the wall, whereupon the topsheet can be applied.

In order to set the acoustic absorption properties, it is provided according to the invention to form sound penetration holes in the upper layer and / or to subdivide the upper layer into regions which are decoupled from one another in terms of vibration.

In order to prevent sound bridges from arising between the sound-absorbing element and walls, according to the invention provision can be made for arranging sound-decoupling elements for defining a peripheral edge of the sound-absorbing element and optionally for vibration isolation between regions of the upper layer to be subdivided. The sound decoupling elements are expediently placed before the application of the underlayer, to which foam tapes are ideally suited. Alternatively, the Schallentkopplungsfugen can also be milled later from the upper class and optionally closed by foam tapes.

In a further development of the method according to the invention for quickly producing a planar underlayer with a certain layer thickness prior to the application of this sublayer at intervals of, for example, 60 - 100 cm to each other peeling strips mounted on the substrate. Thereafter, the material of the underlayer is applied. Immediately after the application of the backsheet, the excess backsheet material is withdrawn through a puller which is passed to the puller bar and which preferably comprises a rotating roller. The Abziehleisten remain even after curing of the lower layer in the same and are covered by the upper layer. This embodiment of the method according to the invention is suitable for producing the underlayer on a wall surface.

In a variant of this method, at a certain distance to the ground, i. to the wall, and clamped at a certain distance parallel guide profiles between the floor and ceiling. Then the extractor is mounted in corresponding guide grooves of the guide profiles and guided along the profiles over the substrate to be deducted in order to remove excess underlayer material. It is preferred to advance the puller by motor. It is further preferred to arrange the guide profiles movable by motor, so that a semi-automatic production of the lower layer by a person is possible. Optionally, the guide profiles may be mounted in a guide linkage and the guide linkage may be designed to be motor-displaceable.

A conveying device which can be used according to the invention has a feed unit for receiving cellulose material, a metering unit for metering the supplied cellulose material and a fan in order to convey the metered cellulose material to a spray head. In order to achieve a uniform, continuous cellulose flow, it is provided that the metering unit has a screw conveyor for continuously conveying the cellulosic material, and that the fan is connected to the output of the screw conveyor. In contrast to the known conveying devices with rotary feeder, the screw conveyor ensures a continuous delivery of the cellulose material supplied to it, the conveying screw causing a homogenization of the delivery flow. The additional measure of arranging the fan at the exit of the screw conveyor, the cellulosic material is sucked out of the screw conveyor, mixed with fresh air and blown through an outlet to a spray head. With the conveying device which can be used according to the invention, the pulsed delivery flows occurring in the known conveying devices can be reliably prevented.

A good efficiency of the invention used according to the conveyor device is achieved when the fan is designed as a radial fan.

In order to uniformly feed the screw conveyor with cellulose material, the conveyor device which can be used according to the invention is provided in one embodiment Equip the metering unit with at least two provided with paddles waves, wherein preferably adjacent shafts are rotatable in opposite directions.

In order to further improve the homogeneity of the cellulose conveying stream, it is advantageous for the dosing unit to be preceded by a cellulose loosening unit which comprises a large number of paddles arranged on rotatable shafts.

The invention will now be described by way of non-limiting embodiments with reference to the drawings.

In the drawings show Fig. 1 a horizontal section through a building exterior wall and an applied on the inside of the wall according to the invention sound-absorbing element, Fig. 2 an interior view of a building wall with a sound-absorbing element according to the invention applied thereto, which is cut open in layers, Fig. 3 a cellulose conveyor according to the invention in perspective, partially cut open and in an exploded view, Fig. 4 the principle of a spray head for use in the manufacture of a sound-absorbing element according to the invention, Fig. 5 a practical spray head for use in the manufacture of a sound-absorbing element according to the invention, Fig. 6 a diagram illustrating the ratio of the proportions by weight of different particle sizes, and Fig. 7 a puller for removing excess material of the underlayer.

First up Fig. 1 With reference thereto, a horizontal section through a building wall 7 and an inventive sound-absorbing element 1 applied thereto are shown in the view from above. The sound-absorbing element 1 has a structure of a lower layer 2 with cellulose as the main constituent and a surface layer 3 of a mineral plaster, which has a higher specific gravity than the lower layer 2 and is connected in a planar manner to the lower layer 2. The upper layer 3 is subdivided into two regions 3, 3 separated from one another by a gap 3a '. The gap 3a 'could also be filled with a vibration decoupling element. For environmental reasons, it is preferred that the cellulose contains a relatively high proportion of waste paper. Furthermore, cellulose binders are added. When Binders on the one hand powdery, water-activatable binders, such as corn starch, can be used. On the other hand, liquid adhesives, such as latex adhesive or polyvinylacetate-based adhesive, can also be used as the binder. Likewise foam adhesives can be used. The amount of binder addition affects the dynamic stiffness of the underlayer 2, which in turn affects the frequency response of the sound absorbing element. To prevent mold formation, a fungicide, such as ammonium phosphate, may be added to the cellulose. It is also possible to add flame-retardant additives, for example borate-based inorganic fire-retardants.

The density of the underlayer 2 of the sound absorbing member 1 is adjusted in addition to the type and amount of binder addition by selecting the average particle size of the cellulose according to a certain grading curve, thus controlling the acoustic properties of the sound absorbing member 1 as well as the quality and mechanical strength of the underlayer 2 are. The grading curve is determined by a set of eight sieves with a diameter of 20 cm and different mesh sizes between 4 and 0.045 mm. It should be noted that the density of the lower layer increases with increasing coarse fraction. The grading curve influences the resonance behavior and thus the frequency-dependent sound absorption behavior of the lower layer 2. Good acoustic properties are exhibited, for example, by a sound-absorbing element in which cellulose having particle sizes in the range of FIG. 6 shown Sieblinie was used.

The upper layer 3 of the sound-absorbing element 1 is formed of a mineral plaster. Thus, the sound-absorbing element can be treated after its application as an ordinary wall and has excellent absorption capacity for room humidity.

Fig. 2 shows an interior view of a building wall 7 made of bricks with a sound-absorbing element 1 according to the invention applied thereto, wherein the element 1 is cut open to illustrate its layer structure. First, on the wall 7, a sound-decoupling member 4, such as a foam tape, is attached, which defines the circumference and the thickness of the sound-absorbing member 1. If the wall 7 bad Adhesion, it may be necessary to apply a primer layer 6, which in the simplest case water for wetting the wall 7 includes, but may also contain additional binder. On this prepared wall is applied by spraying, as explained below, the lower layer 2 of cellulose and binders. There is a full-surface bond between the wall 7 and the lower layer 2. On the lower layer 2, a bonding layer 5 is applied, on which in turn the upper layer 3 is applied. For the preparation of the upper layer 3 of the plaster is applied by hand or machine on the lower layer 2 and then peeled off and triturated the plaster surface. The acoustic attenuation characteristics of the sound absorbing member 1 are set by round sound passage holes 3b and slit-shaped sound passage holes 3a respectively formed in the upper layer 3 and the width-height ratio of the fields formed by the foam strips.

The method for producing the sound-absorbing element 1 on the wall 7 comprises applying the underlayer 2 to the wall 7, wherein the underlayer 2 comprises cellulose particles as a main constituent, which are mixed with binders and optionally additives such as fungicides and / or flame retardants. The lower layer 2 is allowed to air-dry after application and thereby solidify. Subsequently, the upper layer 3 is applied to the lower layer 2 in such a way that a planar connection between the lower layer 2 and the upper layer 3 prevails.

The method for applying the underlayer 2 to the wall 7 is a spraying method in which the cellulose is fed to a spray head and injected with binders offset under pressure on the wall.

However, attempts to spray the binder-added cellulose onto a wall using conventional blow-in machines to convey the cellulosic material to the spray head did not produce the desired results because the flow proved to be extremely inhomogeneous resulting in uneven density and thickness the lower class led. The conventional blowing machines have a storage container, in the material to be transported, such as cellulose flakes, is introduced and loosened by a stirrer. Below the reservoir is a rotary feeder, which has a number of distributed around the circumference of a wheel cells with a given volume. In the bottom of the storage container an ejection surface is formed, the clear width is adjustable by a slider. The cellulosic flakes fall through the ejection surface into the cell of the rotating cell wheel just below the ejection surface and fill the cell. The cell wheel conveys the cellulose flakes into a stream of compressed air, which transports them further to the spray head. Due to the division of the cellulose flakes into discrete cells, varying amounts of cellulose enter the stream of compressed air, namely when a cell moves into the compressed air stream, initially a few cellulose flakes and then the bulk. Between two cells, the stream of cellulose flakes completely disappears. Thus, in the known blowing in a clocked flow.

To remedy the problems described, it was therefore necessary to develop a novel conveying device that can produce a continuous flow of cellulose. Fig. 3 shows in perspective a conveyor device 10 according to the invention for conveying cellulosic material to a spray head. The conveying device 10 comprises a feed hopper 11 into which ground cellulose pulps, optionally mixed with pulverulent binders, are introduced (arrow A). Under the feed hopper 11 is a loosening unit 12, in which a plurality of arranged on shafts 13 paddles 14 loosen the cellulose material and in the direction of arrow B (in the drawing to the left), where it falls through a bottom opening in a metering unit 15 ( Arrow C). The metering unit 15 comprises two counter-rotating shafts 16, on which paddles (16a) are made of spring steel, which press the supplied cellulose flakes into the intake of a screw conveyor 18, which feeds the material continuously to a centrifugal fan 19 (arrow D), the cellulose from the screw conveyor sucked in and mixed with air and the resulting cellulose-air mixture further homogenized and at an output port 20 delivers (arrow E). The output port 20 is connectable to a hose, not shown, the other end opens into a spray head. The shafts 16 and the screw conveyor 18 are driven by an electric motor 17.

Fig. 4 schematically shows a spray head 21, which from the conveyor 10 ( Fig. 3 ) delivered (arrow E) cellulose-air mixture is supplied axially. The spray head 21 is double-walled and includes an outer shell 22 which surrounds an inner shell 23 concentrically. The outer shell 22 has two closable by shut-off valves 25, 26 supply lines G, H, can be supplied through the water, binder, liquid additives or foam adhesive in the annular space between the outer shell 22 and inner shell 23. The inner jacket 23 has a plurality of passage openings distributed over the entire lateral surface, so that the liquid materials introduced through the feed lines G, H reach the interior of the inner jacket 23 and can there connect with the axially conveyed cellulose / air mixture E. This mixture F is ejected axially through the spray nozzle 24, where it attaches to the wall 7 as a lower layer 2.

It should be mentioned that during the spraying process either a foam adhesive, which is of a foam-like consistency, is introduced through the supply line H into the spray head 21 in order to embed and bind the cellulose therein or water which is mixed with liquid adhesive is supplied through the feed line 25 to wet the cellulose as evenly as possible. By the second supply line G further additives can be introduced into the spray head 21.

Fig. 5 shows a presently preferred embodiment of a spray head 27 for spraying a cellulose underlayer on a wall. The spray head 27 is connected to a hose 30, the other end is connectable to a conveyor to promote cellulose to the spray head and eject after previous moistening through the cavity 33. The spray head 27 has a combined internal and external humidification in the form of a central nozzle 32 and ring-shaped arranged on the outside of the spray head annular nozzles 31. The central nozzle 32 is fed via a shut-off valve 29 water-adhesive mixture. The ring nozzles 31 can be supplied via a shut-off valve 28 water-adhesive mixture. The two shut-off valves 28, 29 are independently controllable, so that the flow rates of the water-adhesive mixture to the center nozzle or to the annular nozzles are separately controlled.

For rapid production of a planar underlayer 2 with a certain layer thickness, before the application of this underlayer 2 at intervals of, for example, 60-100 cm, peeling strips 42 can be mounted on the substrate, as in FIG Fig. 7 shown. Thereafter, the material of the underlayer is applied, as explained above. Immediately after application of the backsheet 2, the excess backsheet material is withdrawn through a puller 40, which preferably includes a rotating roller 41, which is passed to the stripper bars 42. The Abziehleisten 42 remain even after curing of the lower layer 2 in the same and are covered by the upper layer. This embodiment of the method according to the invention is suitable both for producing the underlayer on a ceiling and on a wall surface. Alternatively, at a certain distance from the ground, ie to the wall or ceiling, as well as at a certain distance from each other parallel guide profiles between floor and ceiling or between opposite walls or between Profilstehern be braced. Then the extractor is mounted in corresponding guide grooves of the guide profiles and guided along the profiles over the substrate to be deducted in order to remove excess underlayer material. It is preferred to advance the puller by motor. It is further preferred to arrange the guide profiles movable by motor, so that a semi-automatic production of the lower layer by a person is possible. Optionally, the guide profiles may be mounted in a guide linkage and the guide linkage may be designed to be motor-displaceable.

Claims (18)

1. An arrangement of a sound absorbing element attached to the inner side of an external wall of a building, with a configuration comprised of a lower layer (2) with cellulose as the main component and a connected upper layer (3) fully two-dimensionally adhering to the lower layer (2), which has a higher specific weight than the lower layer,
   characterized in that
   the lower layer is sprayed onto the inner side of an external wall of a building (2) and that the upper layer (3) includes a plaster coating made from a mineral plaster also having optionally through-passage openings (3a, 3b) for the sound and/or being divided into areas that are vibration-decoupled from each other.
2. An arrangement according to claim 1, characterized in that the upper layer (3) includes a plaster layer made from a plastic-coated mineral plaster.
3. An arrangement according to any of the preceding claims, characterized in that there have been added binding agents to the lower layer (2).
4. An arrangement according to claim 3, characterized in that the binding agents include powder-like organic binding agents that may activated by water, foam adhesives or liquid adhesives.
5. An arrangement according to claim 4, characterized in that the binding agents include latex adhesives or adhesives on the basis of polyvinyl acetate.
6. An arrangement according to any of the preceding claims, characterized in that the lower layer (2) contains additives such as fungicides and/or flame inhibitors.
7. An arrangement according to any of the preceding claims, characterized in that there is provided a binding layer (5) between the lower layer (2) and the upper layer (3).
8. An arrangement according to any of the preceding claims, characterized in that there are arranged at the circumferential edges at least in part sound decoupling elements (4).
9. A method for the manufacture of an arrangement according to any of claims 1 to 8, characterized by the spraying of a lower layer (2) of cellulose particles containing binding agents and optionally additives such as fungicides and/or flame inhibitors onto the ceiling or wall (7); as far as necessary, the hardening of the lower layer (2); and the applying of an upper layer (3) onto the lower layer (2) by fully two-dimensionally adhering the lower layer to the upper layer, wherein

   - the upper layer has a higher specific weight than the lower layer,

   - the upper layer includes a plaster layer made from mineral plaster, and

   - the upper layer optionally has through-passage openings (3 a, 3b) for the sound and/or is divided into areas that are vibration-decoupled from each other.
10. A method according to claim 9, characterized in that the cellulose particles are mixed with an adhesive foam before being applied onto the wall.
11. A method according to claim 10, characterized in that the cellulose particles are mixed with water before being applied onto the wall.
12. A method according to any of claims 9 to 11, characterized in that before the lower layer is applied, there is applied to the wall (7) an undercoat layer (6), in particular a binding agent layer, improving adhesiveness.
13. A method according to any of claims 9 to 12, characterized by the arrangement of sound decoupling elements (4) for defining a circumferential edge of the sound absorbing element.
14. A method according to any of claims 9 to 13, characterized in that before the lower layer (2) is applied, there are arranged levelling bars (42) in intervals to each other at the wall or ceiling or guidance profiles in a certain distance to the wall or ceiling, and that after applying the lower layer excessive material of the lower layer is levelled by means of a levelling device (40) guided at the levelling bars or guidance profiles and preferably comprising a rotating roller (41).
15. A method according to claim 14, characterized in that the levelling device (40) is advanced by a motor.
16. A method according to claim 14 or 15, characterized in that the guidance profiles are slidable, in particular slidable by a motor.
17. A method according to claim 9, characterized by the lower layer being applied by means of a conveyor device for spraying a lower layer (2) made of cellulose particles containing binding agents and optionally additives onto a ceiling or wall (7),
    wherein the conveyor device has a supplier unit (11) for receiving cellulose material, a dosing unit for dosing the supplied cellulose material and a ventilator for conveying the dosed cellulose material to a spray head, wherein the dosing unit (15) has a conveyor screw (18) for continuously conveying the cellulose material and wherein the ventilator (19) is connected to the exit of the conveyor screw (18), characterized in that there is arranged upstream of the dosing unit (15) a cellulose loosening unit (12) including a plurality of paddles (14) arranged on pivotable shafts (13); wherein in particular the ventilator (19) is formed as a radial ventilator; and/or wherein the dosing unit (15) has at least two shafts (16) provided with paddles (16a), wherein preferably two adjacent shafts are pivotable in opposite directions.
18. A method according to any of claims 9 to 16, characterized in that the lower layer is applied by a conveyor device as defined in claim 17.

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