EP0750777A1 - Foil sound absorber - Google Patents

Foil sound absorber

Info

Publication number
EP0750777A1
EP0750777A1 EP95912132A EP95912132A EP0750777A1 EP 0750777 A1 EP0750777 A1 EP 0750777A1 EP 95912132 A EP95912132 A EP 95912132A EP 95912132 A EP95912132 A EP 95912132A EP 0750777 A1 EP0750777 A1 EP 0750777A1
Authority
EP
European Patent Office
Prior art keywords
sound absorber
film
absorber according
foil sound
foil
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP95912132A
Other languages
German (de)
French (fr)
Other versions
EP0750777B1 (en
Inventor
Helmut Fuchs
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
Original Assignee
Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
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Publication date
Application filed by Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV filed Critical Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
Priority to SI9530271T priority Critical patent/SI0750777T1/en
Publication of EP0750777A1 publication Critical patent/EP0750777A1/en
Application granted granted Critical
Publication of EP0750777B1 publication Critical patent/EP0750777B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/162—Selection of materials
    • G10K11/168—Plural layers of different materials, e.g. sandwiches

Definitions

  • the invention relates to a film absorber for absorbing sound
  • the oscillation amplitude of the plate becomes particularly large at the natural frequencies ".
  • This resonance-like resonance of the partial surfaces with their characteristic bending vibrations meant that high damping of the stimulating sound waves could be achieved at least in the vicinity of a natural frequency even if the internal damping remained relatively low but the deformation of the film material was severe.
  • attempts have been made (“sound absorbing component” - DE 29 21 050, "sound absorbing component” - DE 32 33 654)
  • PVC has in common with many other plastics that - even when used indoors - it is not permanently UV-resistant and therefore discoloration can occur. For reasons of environmental protection, the market is reacting cautiously to all PVC products today. In some countries, the use of PVC in large quantities in buildings is also prohibited for reasons of fire protection.
  • the object of the invention is therefore to provide a film absorber which is simple to manufacture and easy to clean. According to the invention, this is done by the photo lienabsorber solved according to claim 1. Advantageous refinements are characterized in the subclaims.
  • the film absorber according to the invention completely avoids the cup-shaped formations and consists only of several (preferably: 3) completely flat films which are arranged one behind the other (preferably: all parallel to one another and to the wall) in front of a reverberant rear wall (for example a very heavy component) are.
  • the foils can be made of any material, e.g. Plastic or metal. Your transverse dimensions are largely, e.g. according to the respective installation case, freely selectable. 2, their acoustic properties are essentially determined by their basis weights m "and distances D from one another and from the wall.
  • the shape and configuration of the between the films and the wall play, at least in the case of perpendicular sound
  • the voids formed and the type of fastening of the foils to spacers or frames for fastening the absorbers to the rear wall play only a subordinate role in terms of sound technology, since the absorber according to the invention does not essentially derive its effectiveness from the internal damping in the foil material by stimulating bending deformations at kinks , Edges and supports and hardly derived from the friction between contact surfaces or from the friction of vibrating air particles on fine fibers or in narrow pores, it enables a previously unsuitable adaptation of the acoustic design to the respective input in terms of material selection and shape When designing for the same sound spectrum, it requires approximately the same depth and basis weight as the known film absorbers.
  • the film absorber according to the invention according to Figure 2 is, like that according to DE 27 58 041, DE 29 21 050 or DE 32 33 654, a complex resonance system. With its low resistance, similar to the conventional film absorber (see Fuchs, HV; Ackermann, U .; Frommhold, W .: Development of non-porous absorbers for technical sound insulation. Building Physics 1 1 (1 989), p. 28-36), it enables unexpected broadband activity even with a relatively small number of resonance mechanisms (preferably: 3).
  • Figure 3 shows the simplest example of a resonance system constructed from only a single film, an important optimization principle of the absorbers according to the invention.
  • the film For broadband attenuation at high frequencies, the film should have the lowest possible basis weight m "and not (for larger m") prefer a correspondingly smaller distance. In order to optimally absorb at low frequencies, however, not only the basis weight should be increased, but also the thickness D of the air cushion at the same time. In this way it can be achieved that the simplest single-shell structure for low frequencies needs a significantly smaller depth than a homogeneously constructed porous or fibrous absorber.
  • Figure 5 shows a calculation result for three foils of the same weight with a total depth of 100 mm.
  • the comparison with measurements in the so-called impedance tube with a cross-section of 200 x 200 mm ⁇ shows very good agreement up to the measuring limit of 1 200 Hz ( Figure 6).
  • the film absorbers according to the invention can be made absorbent by means of staggered mass / spring systems consisting of thin films with air spaces with almost any broadband absorption, in particular if (as seen in the direction of sound incidence) the basis weights m "of the films are increased and the distances D also enlarged between them towards the wall.
  • the cavity resonator which is formed by the film 1, the side frames 2 or spacers and the rear wall R, is advantageously gas-tight.
  • the film absorber according to the invention can be designed to be acoustically broadband and to be manufactured significantly more cost-effectively and, because of the closed surface, it is more maintenance-friendly.
  • the flat, completely flat and smooth construction of the film absorber according to the invention offers significant advantages with regard to deposits and cleaning.
  • the flat film absorber can be manufactured significantly more simply and cost-effectively.
  • the film absorber according to the invention can be configured as desired, similarly to silencers made of homogeneous mineral wool, and can be modularly constructed, preferably together with the hard-walled rear wall, as a sound-absorbing component with the Create the required stiffness in freely selectable dimensions.
  • a water-impermeable, thin cloth can be obtained as the first film facing the room.
  • a particularly resistant variant can also use novel, extremely tear-resistant, thin plastic fabric as the first film.
  • the film absorber according to the invention offers a variety hitherto unknown for sound absorbers, which accommodates its use in room acoustics.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Building Environments (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)
  • Chair Legs, Seat Parts, And Backrests (AREA)
  • Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
  • Accessory Devices And Overall Control Thereof (AREA)
  • Laminated Bodies (AREA)
  • Diaphragms For Electromechanical Transducers (AREA)

Abstract

PCT No. PCT/DE95/00341 Sec. 371 Date Nov. 18, 1996 Sec. 102(e) Date Nov. 18, 1996 PCT Filed Mar. 13, 1995 PCT Pub. No. WO95/25325 PCT Pub. Date Sep. 21, 1995A foil sound absorber consists of at least two smooth, flat and air-tight foils separated from each other and from a reverberant rear wall R by different distances D.

Description

BESCHREIBUNG DESCRIPTION
Folien-SchallabsorberFoil sound absorber
Die Erfindung betrifft einen Folienabsorber zur Absorption von SchallThe invention relates to a film absorber for absorbing sound
1. Einleitung1 Introduction
In der Raumakustik (z.B. bei Wand- und Decken-Auskleidungen), in der Lärmbe¬ kämpfung an lauten Maschinen (z.B. bei Kapselungen und Abschirmungen) sowie beim technischen Schallschutz (z.B. durch Schalldämpfer in Strömungskanälen) dominiert, wie in Bild 1 angedeutet, der Einsatz von mehr oder weniger homoge¬ nen Schichten aus faserigem/porösem Material (z.B. künstlicher Mineralfaser (KMF)). Die jahrelange Diskussion über mögliche Gefährdungen durch Feinstäube und Fasern (Köster, J.; Grünau, E.B.: Mineralfasern: Eine Gefahrenquelle, Expert- Verlag, Ehningen, 1993) sowie durch Ablagerungen und Keimbildung in solchen Schichten hat dazu geführt, daß man einerseits das poröse Material mit geeigneten Folien und Vliesen abzudecken und einzupacken versucht und andererseits nach alternativen Schallabsorbern sucht, die ganz ohne den Einsatz solcher porösen Materialien auskommen. Bei der Anmelderin führte diese Suche frühzeitig zur Entwicklung von drei ganz unterschiedlich aufgebauten Absorbern für völlig ver¬ schiedene schalltechnische Anwendungen ("Schallabsorbierendes Bauelement" - DE 27 58 041 ; "Schalldämpfer-Box" DE 34 04 208; "Schallabsorbierendes Glas¬ oder Kunstglas-Bauteil" DE- 43 1 5 759). Sie können - jeder für sich, aber auch in Kombination und zur Ergänzung der Wirksamkeit konventioneller Absorber - einen weiten Frequenzbereich von ca. 50 Hz aufwärts bis in den kHz-Bereich und ein sehr breites Anwendungsfeld abdecken. Es fehlte auch nicht an mehr oder minder erfolgreichen Versuchen, die Wirkungs-Mechanismen in diesen meist flächig auf¬ gebauten Absorbern zu beschreiben. So wird z.B. in Mechel F.; Kiesewetter, N.: Schallabsorber aus Kunststoff-Folie. Acustica 47 (1 981 ), S. 83-88 gezeigt, daß eine ebene Kunststoff-Folie, die von einer schräg auftreffenden Schallwelle zu er¬ zwungenen Biegewellen angeregt wird, nicht in der Lage ist, einen wesentlichen Teil der Schallenergie durch innere Reibung zu vernichten. Um den Dissipations- grad trotzdem wesentlich zu erhöhen, wird vorgeschlagen, die Folie so zu verfor- men, daß "rechteckige Flächenstücke von einigen Zentimetern Länge und Breite entstehen, die am Rande durch einen Knick begrenzt sind. Der Knick am Rande dieser Platten wirkt als Befestigung und hindert die Folie an dieser Stelle in ihrer freien Bewegung. Dadurch wird die Platte zu Eigenschwingungen angeregt. Die Wellenlängen dieser Eigenschwingungsformen sind im Frequenzbereich bis zu 5000 Hz wesentlich kleiner als die Spurwellenlänge der auftreffenden Luftschall¬ welle. Die Schwingungsamplitude der Platte wird besonders groß bei den Eigen¬ frequenzen". Durch dieses resonanzartige Mitschwingen der Teilflächen bei ihren charakteristischen Biegeschwingungen meinte man, auch bei weiterhin verhält¬ nismäßig geringer innerer Dämpfung, aber starker Verformung des Folienmaterials zumindest in der Nähe einer Eigenfrequenz hohe Dämpfung der anregenden Schallwellen erreichen zu können. Um trotz dieser prinzipiell auf nur schmale Fre¬ quenzbänder beschränkten Wirkungsweise profilierter Folien zu einem breitbandi- gen Schallabsorber zu gelangen, hat man versucht ("Schallabsorbierendes Bau¬ element" - DE 29 21 050, "Schallabsorbierendes Bauelement" - DE 32 33 654)In room acoustics (e.g. for wall and ceiling linings), in noise abatement on noisy machines (e.g. encapsulation and shielding) and in technical noise protection (e.g. through silencers in flow channels), use is dominant, as indicated in Figure 1 of more or less homogeneous layers of fibrous / porous material (eg artificial mineral fiber (KMF)). The years of discussion about possible dangers from fine dust and fibers (Köster, J .; Grünau, EB: mineral fibers: A source of danger, Expert Verlag, Ehningen, 1993) as well as through deposits and nucleation in such layers has led to the fact that on the one hand the porous Tried to cover and pack material with suitable foils and nonwovens and, on the other hand, is looking for alternative sound absorbers that can do without the use of such porous materials. For the applicant, this search led early to the development of three completely different absorbers for completely different acoustic applications ("sound-absorbing component" - DE 27 58 041; "silencer box" DE 34 04 208; "sound-absorbing glass or synthetic glass - Component "DE-43 1 5 759). They can cover a wide frequency range from approx. 50 Hz up to the kHz range and a very wide range of applications - each individually, but also in combination and to supplement the effectiveness of conventional absorbers. There was also no lack of more or less successful attempts to describe the mechanisms of action in these mostly flat absorbers. For example, in Mechel F .; Kiesewetter, N .: Sound absorber made of plastic film. Acustica 47 (1 981), pp. 83-88 showed that a flat plastic film, which is excited by an obliquely incident sound wave to force bending waves, is not able to destroy a substantial part of the sound energy through internal friction. In order to significantly increase the degree of dissipation, it is proposed to deform the film in such a way that "rectangular areas of a few centimeters in length and width are created, which are delimited at the edge by a kink. The kink at the edge of these plates acts as Attachment and prevents the film from moving freely at this point. This causes the plate to vibrate naturally. The wavelengths of these natural oscillation forms in the frequency range up to 5000 Hz are considerably smaller than the track wavelength of the impinging airborne sound wave. The oscillation amplitude of the plate becomes particularly large at the natural frequencies ". This resonance-like resonance of the partial surfaces with their characteristic bending vibrations meant that high damping of the stimulating sound waves could be achieved at least in the vicinity of a natural frequency even if the internal damping remained relatively low but the deformation of the film material was severe. In order to achieve a broadband sound absorber in spite of this principle of action of profiled foils, which is limited to only narrow frequency bands, attempts have been made ("sound absorbing component" - DE 29 21 050, "sound absorbing component" - DE 32 33 654)
durch Tiefziehen in den Boden- und Seitenflächen der Folien Platten unter¬ schiedlicher Größe zu schaffen, durch Bevorzugung rechteckig langgestreckter anstelle von quadratischen Teilflächen innerhalb einer und derselben Platte eine höhere Zahl von Eigen¬ frequenzen anregbar zu machen, durch vielfache, kleinere und größere Verformungen sowie zusätzliche Masse-Einschlüsse in den tiefgezogenen Folien eine solche Vielfalt der Ei¬ genschwingungen zu ermöglichen, daß praktisch alle interessierenden Fre¬ quenzanteile des zu dämpfenden Schallfeldes möglichst vollständig absor¬ biert werden können. Ergebnis dieser Optimierung von 10 und mehr gleichzeitig anregbaren Biege¬ schwingungen ist eine stark zerklüftete, rauhe Oberfläche des Schallabsorbers. 2. Nachteile der konventionellen Folien-Absorberto create plates of different sizes by deep drawing in the bottom and side surfaces of the foils, to make it possible to excite a higher number of natural frequencies by preferentially elongated rather than square partial areas within one and the same plate, by means of multiple, smaller and larger deformations and additional mass inclusions in the deep-drawn foils to enable such a variety of natural vibrations that practically all frequency components of interest in the sound field to be damped can be absorbed as completely as possible. The result of this optimization of 10 and more bending vibrations which can be excited simultaneously is a strongly jagged, rough surface of the sound absorber. 2. Disadvantages of conventional film absorbers
Die oben beschriebenen Becher-Ausprägungen, Profilierungen, Strukturierungen, Eintiefungen, Sicken und Nuten in den bisher verwendeten Folien-Absorbern wei¬ sen eine Reihe schwerwiegender Nachteile auf: ihre Herstellung gelingt bisher mit vertretbarem Aufwand nur mit bestimmten Folien auf Polyvinylchlorid (PVC)-Basis. Andere Kunststoff-Folien mit vergleichbaren inneren Verlusten zur Energie-Dissipa- tion der Biegeschwingungen lassen derartige Verformungen nicht zu.The cup designs, profiles, structuring, recesses, beads and grooves described above in the film absorbers used hitherto have a number of serious disadvantages: their manufacture has so far been possible with reasonable effort only with certain films based on polyvinyl chloride (PVC) . Other plastic films with comparable internal losses for energy dissipation of the bending vibrations do not allow such deformations.
PVC hat mit vielen anderen Kunststoffen gemeinsam, daß es - selbst bei der An¬ wendung in Innenräumen - nicht dauerhaft UV-beständig ist und deshalb Verfär¬ bungen eintreten können. Aus Gründen des Umweltschutzes reagiert der Markt heute zurückhaltend auf alle PVC-Produkte. In manchen Ländern ist die Verwen¬ dung von PVC in größeren Mengen in Gebäuden auch aus Gründen des Brand¬ schutzes untersagt.PVC has in common with many other plastics that - even when used indoors - it is not permanently UV-resistant and therefore discoloration can occur. For reasons of environmental protection, the market is reacting cautiously to all PVC products today. In some countries, the use of PVC in large quantities in buildings is also prohibited for reasons of fire protection.
Solange die dünnen (0,2 - 0,4 mm dicken) Folien beim Tiefziehen nicht reißen und auch bei der Montage sowie bei der Wartung nicht verletzt werden, sind die einge¬ schlossenen Hohlräume zwar dauerhaft gegen eindringende Feuchtigkeit und Ver¬ schmutzungen geschützt. Aber die charakteristische, zerklüftete Oberfläche bietet in staubhaltiger, feuchter Umgebung dennoch Möglichkeiten für Ablagerungen und Verschmutzungen aller Art. In Naßräumen kann diesen zwar durch Abwaschen und Abbürsten bis zu einem gewissen Grade begegnet werden. Eine intensivere und häufigere Reinigung wirkt sich aber dennoch negativ auf die Dauerhaltbarkeit dieser Art von Folien-Absorbern aus.As long as the thin (0.2-0.4 mm thick) foils do not tear during deep drawing and are not damaged during assembly or maintenance, the enclosed cavities are permanently protected against the ingress of moisture and dirt. But the characteristic, jagged surface offers possibilities for deposits and soiling of all kinds in dusty, humid surroundings. In wet rooms, these can be countered to a certain extent by washing and brushing. However, more intensive and frequent cleaning has a negative impact on the durability of this type of film absorber.
Alle diese Nachteile schränken die Materialauswahl zur Herstellung der herkömmli¬ chen Folien-Absorber sowie ihre Anwendbarkeit im Bereich der Raumakustik und des technischen Schallschutzes zur Wandauskleidung und Schallkapselung erheb¬ lich ein. Als Schalldämpfer in Lüftungskanälen haben sich Folien-Absorber bisher überhaupt nicht bewährt.All of these disadvantages considerably restrict the choice of materials for producing the conventional film absorbers and their applicability in the field of room acoustics and technical sound insulation for wall lining and sound encapsulation. So far, film absorbers have not proven themselves as silencers in ventilation ducts.
Aufgabe der Erfindung ist es daher, einen Folienabsorber zu schaffen, der einfach herzustellen ist und einfach zu reinigen. Erfindungsgemäß wird dies durch den Fo- lienabsorber nach Anspruch 1 gelöst. Vorteilhafte Ausgestaltungen sind in den Unteransprüchen gekennzeichnet.The object of the invention is therefore to provide a film absorber which is simple to manufacture and easy to clean. According to the invention, this is done by the photo lienabsorber solved according to claim 1. Advantageous refinements are characterized in the subclaims.
3. Darstellung der Erfindung3. Presentation of the invention
Der erfindungsgemäße Folien-Absorber vermeidet die becherförmigen Ausformun¬ gen ganz und besteht nur aus mehreren (bevorzugt: 3) völlig ebenen Folien, die vor einer schallharten Rückwand (z.B. einem sehr schweren Bauteil) hintereinander (bevorzugt: alle parallel zueinander und zur Wand) angeordnet sind. Die Folien kön¬ nen aus beliebigem Material, z.B. Kunststoff oder Metall, sein. Ihre Querabmes¬ sungen sind weitgehend, z.B. dem jeweiligen Einbaufall entsprechend, frei wähl¬ bar. Ihre akustischen Eigenschaften werden gemäß Bild 2 im wesentlichen von ihren Flächengewichten m" und Abständen D zueinander und zur Wand bestimmt. Im Gegensatz zum herkömmlichen Folien-Absorber spielen, zumindest beim senk¬ rechten Schalleinfall, die Form und Ausgestaltung der zwischen den Folien und der Wand gebildeten Hohlräume sowie der Art der Befestigung der Folien auf Ab¬ standshaltern oder Rahmen zur Befestigung der Absorber an der Rückwand eine nur untergeordnete schalltechnische Rolle. Da der erfindungsgemäße Absorber seine Wirksamkeit nicht wesentlich aus der inneren Dämpfung im Folien-Material durch Anregung von Biegeverformungen an Knickungen, Kanten und Auflagern und auch kaum aus der Reibung zwischen Kontaktflächen oder aus der Reibung schwingender Luftteilchen an feinen Fasern oder in engen Poren ableitet, ermög¬ licht er hinsichtlich Materialauswahl und Formgebung eine bisher nicht mögliche Anpassung der schalltechnischen Auslegung auf den jeweiligen Einsatzfall. Dabei benötigt er bei Auslegung auf dasselbe Schallspektrum etwa gleiche Bautiefe und etwa gleiches Flächengewicht wie die bekannten Folien-Absorber.The film absorber according to the invention completely avoids the cup-shaped formations and consists only of several (preferably: 3) completely flat films which are arranged one behind the other (preferably: all parallel to one another and to the wall) in front of a reverberant rear wall (for example a very heavy component) are. The foils can be made of any material, e.g. Plastic or metal. Your transverse dimensions are largely, e.g. according to the respective installation case, freely selectable. 2, their acoustic properties are essentially determined by their basis weights m "and distances D from one another and from the wall. In contrast to conventional film absorbers, the shape and configuration of the between the films and the wall play, at least in the case of perpendicular sound The voids formed and the type of fastening of the foils to spacers or frames for fastening the absorbers to the rear wall play only a subordinate role in terms of sound technology, since the absorber according to the invention does not essentially derive its effectiveness from the internal damping in the foil material by stimulating bending deformations at kinks , Edges and supports and hardly derived from the friction between contact surfaces or from the friction of vibrating air particles on fine fibers or in narrow pores, it enables a previously unsuitable adaptation of the acoustic design to the respective input in terms of material selection and shape When designing for the same sound spectrum, it requires approximately the same depth and basis weight as the known film absorbers.
Der erfindungsgemäße Folien-Absorber nach Bild 2 ist, ähnlich wie derjenige nach DE 27 58 041 , DE 29 21 050 oder DE 32 33 654, ein komplexes Resonanz-Sy¬ stem. Mit seinem, ähnlich dem herkömmlichen Folien-Absorber, geringen Kennwi¬ derstand (vgl. Fuchs, H.V.; Ackermann, U.; Frommhold, W.: Entwicklung von nichtporösen Absorbern für den technischen Schallschutz. Bauphysik 1 1 (1 989), S. 28-36 ) ermöglicht er bereits bei einer verhältnismäßig kleinen Zahl von Reso¬ nanz-Mechanismen (bevorzugt: 3) eine unerwartet breitbandige Wirksamkeit. Bild 3 zeigt am einfachsten Beispiel eines nur aus einer einzigen Folie aufgebauten Resonanz-Systems ein wichtiges Optimierungs-Prinzip der erfindungsgemäßen Ab¬ sorber. Für eine breitbandige Dämpfung bei hohen Frequenzen sollte die Folie ein möglichst geringes Flächengewicht m" aufweisen und nicht etwa (bei größerem m") einen entsprechend kleineren Abstand bevorzugen. Um dagegen bei tiefen Frequenzen optimal zu absorbieren, sollte nicht etwa nur das Flächengewicht vergrößert werden, sondern gleichzeitig die Dicke D des Luftkissens. So läßt sich erreichen, daß bereits der einfachste einschalige Aufbau für tiefe Frequenzen mit deutlich geringerer Bautiefe auskommt als ein homogen aufgebauter poröser oder faseriger Absorber.The film absorber according to the invention according to Figure 2 is, like that according to DE 27 58 041, DE 29 21 050 or DE 32 33 654, a complex resonance system. With its low resistance, similar to the conventional film absorber (see Fuchs, HV; Ackermann, U .; Frommhold, W .: Development of non-porous absorbers for technical sound insulation. Building Physics 1 1 (1 989), p. 28-36), it enables unexpected broadband activity even with a relatively small number of resonance mechanisms (preferably: 3). Figure 3 shows the simplest example of a resonance system constructed from only a single film, an important optimization principle of the absorbers according to the invention. For broadband attenuation at high frequencies, the film should have the lowest possible basis weight m "and not (for larger m") prefer a correspondingly smaller distance. In order to optimally absorb at low frequencies, however, not only the basis weight should be increased, but also the thickness D of the air cushion at the same time. In this way it can be achieved that the simplest single-shell structure for low frequencies needs a significantly smaller depth than a homogeneously constructed porous or fibrous absorber.
Diese Tendenz verstärkt sich noch bei mehrschichtig aufgebauten erfindungsge¬ mäßen Folien-Absorbern: durch Anbringung von Folie 1 zusätzlich vor Folie 2 in Bild 4 verschiebt sich der zu tiefen Frequenzen abfallende Teil der Dämpfungskurve um 1 - 2 Terzen.This tendency is even more pronounced in the case of multilayer film absorbers according to the invention: by adding film 1 additionally to film 2 in FIG. 4, the part of the damping curve which drops to low frequencies is shifted by 1-2 thirds.
Bild 5 zeigt ein Rechenergebnis für drei gleich schwere Folien mit einer gesamten Bautiefe von 100 mm. Der Vergleich mit Messungen im sogenannten Impedanz¬ rohr mit einem Querschnitt von 200 x 200 mm^ zeigt sehr gute Übereinstimmung bis zur Meßgrenze von 1 200 Hz (Bild 6).Figure 5 shows a calculation result for three foils of the same weight with a total depth of 100 mm. The comparison with measurements in the so-called impedance tube with a cross-section of 200 x 200 mm ^ shows very good agreement up to the measuring limit of 1 200 Hz (Figure 6).
Messungen im sogenannten Hallraum folgen den Rechenergebnissen ebenfalls recht gut, siehe Bild 7 und 8.Measurements in the so-called reverberation room also follow the calculation results quite well, see Figures 7 and 8.
In Bild 8 wurden zusätzlich die Meßergebnisse aus Bild 2 von DE 27 58 041 für einen in der Bautiefe und dem Flächengewicht ungefähr vergleichbaren Folien-Ab¬ sorber eingetragen. Den Vergleich von zwei dreischalig aufgebauten Folien-Absor¬ bern entsprechend etwa Bild 3 mit A = 50 mm zeigt Bild 9. Offenbar lassen sich mit dem erfindungsgemäßen Folien-Absorber die tieferen Frequenzen, mit dem Folien-Absorber nach der DE 27 58 041 dagegen die höheren etwas besser absorbieren. Das Defizit des ebenen Folien-Absorbers läßt sich durch eine einfache Kassettie- rung der großflächigen Luftkissen bei dem im Hallraum sowie in größeren Räumen allgemein dominierenden schrägen Schalleinfall wettmachen. Dazu ist es not¬ wendig, die Luftzwischenräume nach Bild 10 mit einer regelmäßigen (z.B. bie- nenwabenförmigen) oder auch unregelmäßigen (z.B. aus zerknüllten Folien beste¬ henden) Rasterstruktur so zu unterteilen, daß dadurch Teilräume von der Größe weniger cm entstehen. Die Kassettierung kann dabei durch Zwischenwände aus Kunststoff oder Metall erfolgen, die Folien sollen jedoch die Innenkassette nicht berühren bzw. nicht aufliegen. Sie kann an den Seitenberandungen des Folienab¬ sorbers selbst aufgehängt bzw. befestigt sein. Eine solche Optimierung bei hohen Frequenzen ist z.B. vom streifenden Schalleinfall bei Schalldämpfer-Kulissen in Strömungskanälen her bekannt, die deshalb innen "kassettiert" ausgeführt wer¬ den. Es sei aber betont, daß zur Minderung schädlicher Reflexionen in der Raum¬ akustik auch häufig Schallabsorber verlangt werden, die insbesondere die etwa senkrecht auftreffenden Schallwellen absorbieren können.In Figure 8, the measurement results from Figure 2 of DE 27 58 041 were also entered for a film absorber which was approximately comparable in terms of structural depth and basis weight. Figure 9 shows a comparison of two three-layered film absorbers, corresponding to approximately Figure 3 with A = 50 mm. Apparently, the lower frequencies can be achieved with the film absorber according to the invention, but with the film absorber according to DE 27 58 041 absorb higher something better. The deficiency of the flat film absorber can be compensated for by a simple cassette of the large air cushions in the case of the oblique sound that generally dominates in the reverberation room and in larger rooms. For this purpose, it is necessary to subdivide the air gaps according to Figure 10 with a regular (eg honeycomb-shaped) or irregular (for example consisting of crumpled foils) grid structure in such a way that partial spaces of a size of a few cm are created. The cassette can be made using plastic or metal partitions, but the foils should not touch or rest on the inner cassette. It can be hung or fastened to the side edges of the film absorber itself. Such an optimization at high frequencies is known, for example, from the grazing sound incidence in the case of silencer backdrops in flow channels, which are therefore carried out "cassette-coated" on the inside. However, it should be emphasized that in order to reduce harmful reflections in room acoustics, sound absorbers are also often required, which can in particular absorb the approximately perpendicularly incident sound waves.
4. Vorteile ebener Folien-Absorber4. Advantages of flat film absorbers
Die erfindungsgemäßen Folien-Absorber lassen sich durch hintereinander gestaffelt angeordnete Masse/Feder-Systeme bestehend aus dünnen Folien mit Luftzwi¬ schenräumen nahezu beliebig breitbandig absorbierend machen, insbesondere dann, wenn man (in Schalleinfallsrichtung gesehen) Flächengewichte m" der Folien steigert und die Abstände D zwischen ihnen zur Wand hin ebenfalls vergrößert.The film absorbers according to the invention can be made absorbent by means of staggered mass / spring systems consisting of thin films with air spaces with almost any broadband absorption, in particular if (as seen in the direction of sound incidence) the basis weights m "of the films are increased and the distances D also enlarged between them towards the wall.
Der Hohlraumresonator, der durch die Folie 1 , die seitlichen Rahmen 2 oder Ab- standshalterungen und die Rückwand R gebildet wird, ist dabei vorteilhafterweise gasdicht ausgebildet.The cavity resonator, which is formed by the film 1, the side frames 2 or spacers and the rear wall R, is advantageously gas-tight.
Wählt man z.B. glasklare Folien aus Acrylglas mit Dicken mit ungefähr 0,1 bis 0,5 mm, so läßt sich ein völlig transparenter Absorber aufbauen, der - zumindest bei senkrechtem Schalleinfall - den gesamten für die Verständlichkeit von Sprache wichtigen Frequenzbereich optimal absorbiert. (Für Frequenzen oberhalb 1 - 2 kHz ist in Mehrzweckräumen für Sprache und Musik regelmäßig bereits durch Ausstat¬ tung und Publikum genügend Absorption vorhanden ). Gegenüber dem Kunstglas- Bauteil nach DE 43 1 5 759 mit seiner mikro-perforierten Lochplatte als Schallab¬ sorber läßt sich der erfindungsgemäße Folien-Absorber akustisch breitbandiger auslegen und bedeutend kostengünstiger herstellen und wegen der geschlossenen Fläche wartungsfreundlicher gestalten.If, for example, one chooses crystal-clear foils made of acrylic glass with thicknesses of approximately 0.1 to 0.5 mm, a completely transparent absorber can be built up, which - at least with vertical sound incidence - optimally absorbs the entire frequency range important for the intelligibility of speech. (For frequencies above 1 - 2 kHz, there is already sufficient absorption by the equipment and the public in multi-purpose rooms for speech and music). Opposite the art glass Component according to DE 43 1 5 759 with its micro-perforated perforated plate as sound absorber, the film absorber according to the invention can be designed to be acoustically broadband and to be manufactured significantly more cost-effectively and, because of the closed surface, it is more maintenance-friendly.
Wählt man dagegen mechanisch und chemisch hochbeständige Folien aus Kunst¬ stoffen, Metallen oder Verbundwerkstoffen, so läßt sich auch ein sehr robuster und breitbandiger Absorber für den technischen Schallschutz entwerfen, der ganz ohne empfindliche faserige oder poröse Materialien auskommt.If, on the other hand, mechanically and chemically highly resistant films made of plastics, metals or composite materials are selected, then a very robust and broadband absorber for technical sound insulation can be designed, which does not need any sensitive fibrous or porous materials.
Die flächige, völlig ebene und glatte Bauweise des erfindungsgemäßen Folien-Ab¬ sorbers bietet hinsichtlich Ablagerungen und Reinigung wesentliche Vorteile.The flat, completely flat and smooth construction of the film absorber according to the invention offers significant advantages with regard to deposits and cleaning.
Gegenüber dem Membran-Absorber nach DE 34 04 208 mit seiner aufwendigen Unterkonstruktion aus gegeneinander abgeschlossenen Hohlkammern kann der ebene Folien-Absorber bedeutend einfacher und kostengünstiger hergestellt wer¬ den.Compared to the membrane absorber according to DE 34 04 208 with its elaborate substructure made of hollow chambers sealed against one another, the flat film absorber can be manufactured significantly more simply and cost-effectively.
Da er an keine bestimmten Raster als Unterkonstruktion oder Rahmen gebunden ist, läßt sich der erfindungsgemäße Folien-Absorber - ähnlich wie Schalldämpfer aus homogener Mineralwolle - beliebig elementieren und in Modulbauweise, be¬ vorzugt zusammen mit der schallharten Rückwand, als schallabsorbierendes Bau¬ teil mit der erforderlichen Steifigkeit in frei wählbaren Abmessungen herstellen.Since it is not bound to a specific grid as a substructure or frame, the film absorber according to the invention can be configured as desired, similarly to silencers made of homogeneous mineral wool, and can be modularly constructed, preferably together with the hard-walled rear wall, as a sound-absorbing component with the Create the required stiffness in freely selectable dimensions.
Eine weitere Ausführungsform, z.B. für Schwimmhallen, kann als dem Raum zuge¬ kehrte erste Folie ein wasserundurchlässiges, dünnes Tuch erhalten. Eine beson¬ ders widerstandsfähige Variante kann als erste Folie auch neuartige, äußerst rei߬ feste, dünne Kunststoff-Gewebe verwenden.Another embodiment, e.g. for swimming pools, a water-impermeable, thin cloth can be obtained as the first film facing the room. A particularly resistant variant can also use novel, extremely tear-resistant, thin plastic fabric as the first film.
In der Farbgestaltung und Oberflächenstruktur bietet der erfindungsgemäße Folien- Absorber eine bisher für Schallabsorber nicht bekannte Vielfalt, die seinem Einsatz in der Raumakustik entgegenkommt. In terms of color design and surface structure, the film absorber according to the invention offers a variety hitherto unknown for sound absorbers, which accommodates its use in room acoustics.

Claims

Patentansprüche claims
1. Folien-Schallabsorber, wobei mindestens zwei glatte, ebene, luftundurch¬ lässige Folien (1) mit verschiedenem Abstand D zueinander und zu einer schallharten Rückwand R angeordnet sind.1. Foil sound absorber, wherein at least two smooth, flat, air-impermeable foils (1) are arranged at different distances D from one another and to a reverberant rear wall R.
Folien-Schallabsorber nach Anspruch 1,Foil sound absorber according to claim 1,
dadurch gekennzeichnet,characterized,
daß das Flächengewicht m" der Folien 0,05 - 1 kg/m^, und der Abstand D 5- 100 mm beträgt.that the basis weight m "of the films 0.05 - 1 kg / m ^, and the distance D is 5- 100 mm.
Foiien-Schallabsorber nach den Ansprüchen 1 - 2,Foil sound absorber according to claims 1-2,
dadurch gekennzeichnet,characterized,
daß die Folien mit steigendem Flächengewicht m" und etwa in gleichem Maße steigendem Abstand D zur Rückwand angeordnet sind.that the foils are arranged with increasing basis weight m "and approximately the same increasing distance D to the rear wall.
Folien-Schallabsorber nach den Ansprüchen 1 - 3,Foil sound absorber according to claims 1-3,
dadurch gekennzeichnet,characterized,
daß die Folien auf Abstandshalterungen oder Rahmen (2) aus Metall, Kunst¬ stoff, Verbundwerkstoffen am äußeren Rand befestigt sind. that the foils are attached to spacers or frames (2) made of metal, plastic, composite materials on the outer edge.
5. Folien-Schallabsorber nach den Ansprüchen 1 - 4,5. foil sound absorber according to claims 1-4,
dadurc h gekennz eichnet ,characterized ,
daß die freihängende Fläche der Folie etwa 0,1 ... - 1 m^ beträgt.that the free hanging surface of the film is about 0.1 ... - 1 m ^.
6. Folien-Schallabsorber nach den Ansprüchen 1 - 5,6. foil sound absorber according to claims 1-5,
da d urch g e kennz eichnet,characterized,
daß die Folie aus Kunststoff, Acrylglas, Metall, z.B. Aluminium, oder Ver¬ bundwerkstoffen besteht.that the film made of plastic, acrylic glass, metal, e.g. Aluminum, or composite materials.
7. Folien-Schallabsorber nach den Ansprüchen 1 - 6,7. foil sound absorber according to claims 1-6,
dadurch gekennzeichnet,characterized,
daß die Luftzwischenräume regelmäßig oder unregelmäßig kassettiert sind, wobei die Innenkassetten die schwingende Folie nicht behindern, anderer¬ seits aber die Schallausbreitung im Luftzwischenraum unterbinden, und die Wände (3) der Innenkassetten starr und aus dem gleichen oder verschiede¬ nem Material ausgebildet sind.that the air gaps are regularly or irregularly cassette-shaped, the inner cassettes not obstructing the vibrating film, but on the other hand preventing sound propagation in the air gap, and the walls (3) of the inner cassettes being rigid and made of the same or different material.
8. Folien-Schallabsorber nach den Ansprüchen 1 -7,8. foil sound absorber according to claims 1 -7,
dadurch g ekennzeichnet,characterized,
daß die äußerste Folie aus wasserundurchlässigem Gewebe, Tuch oder Kunststoffgewebe besteht. that the outermost film consists of waterproof fabric, cloth or plastic fabric.
9. Folien-Schallabsorber nach den Ansprüchen 1 -8,9. foil sound absorber according to claims 1 -8,
dad urch g ekennz eichnet,characterized,
daß die äußere Folie gefärbt und/oder bedruckt ist.that the outer film is colored and / or printed.
10. Folien-Schallabsorber nach den Ansprüchen 1 - 9,10. Foil sound absorber according to claims 1-9,
dadurch gekennzeichnet,characterized,
daß der Hohlraum, der durch die Folie (1), den Rahmen (2) und die Rück¬ wand R gebildet ist, gasdicht ausgebildet ist. that the cavity formed by the film (1), the frame (2) and the rear wall R is gas-tight.
EP95912132A 1994-03-15 1995-03-13 Foil sound absorber Expired - Lifetime EP0750777B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
SI9530271T SI0750777T1 (en) 1994-03-15 1995-03-13 Foil sound absorber

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE4408782 1994-03-15
DE4408782A DE4408782A1 (en) 1994-03-15 1994-03-15 Foil sound absorber
PCT/DE1995/000341 WO1995025325A1 (en) 1994-03-15 1995-03-13 Foil sound absorber

Publications (2)

Publication Number Publication Date
EP0750777A1 true EP0750777A1 (en) 1997-01-02
EP0750777B1 EP0750777B1 (en) 1999-07-28

Family

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Country Status (8)

Country Link
US (1) US5750944A (en)
EP (1) EP0750777B1 (en)
JP (1) JPH09510303A (en)
AT (1) ATE182713T1 (en)
DE (2) DE4408782A1 (en)
ES (1) ES2135712T3 (en)
GR (1) GR3031089T3 (en)
WO (1) WO1995025325A1 (en)

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Publication number Publication date
JPH09510303A (en) 1997-10-14
WO1995025325A1 (en) 1995-09-21
ATE182713T1 (en) 1999-08-15
US5750944A (en) 1998-05-12
DE59506479D1 (en) 1999-09-02
ES2135712T3 (en) 1999-11-01
EP0750777B1 (en) 1999-07-28
DE4408782A1 (en) 1995-09-21
GR3031089T3 (en) 1999-12-31

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