Air-conditioning duct attenuator

Description

[0001] The invention relates to a sound attenuator according to the preamble of claim 1, which attenuator can be installed in an air-conditioning duct.

[0002] The invention also relates to a method according to the preamble of claim 10 for manufacturing a sound attenuator.

[0003] In the prior art there is known a disk valve which can be installed in the exhaust air duct connection of a room space. The speed and quantity of the air flow are adjusted by turning the valve closing disk around its axis, so that the slot between the closing disk and the valve housing grows or diminishes depending on the winding direction of the closing disk.

[0004] A drawback with a disk valve is that the creation of an air flow with a given direction requires a possibility to measure the slot between the closing disk and the valve housing, and respectively a precise adjusting of the slot. However, this only results in an approximate adjusting of the air flow. Another drawback with a disk valve is that it has poor noise attenuation qualities, wherefore noise attenuation proper must be realized by means of a separate structure.

[0005] From the Finnish utility model application U-920690, there is known an air-conditioning duct adjusting device, wherein orifice holes are cut in the throttle damper, and the adjusting of the air flow quantity is carried out by covering a sufficient number of said holes by rubber or plastic plugs. The adjusting of the air flow with this type of adjusting device is more precise than with a disk valve, but again the drawback of said adjusting member is the lack of noise attenuation, in which case noise attenuation must be realized by means of a separate structure.

[0006] In the prior art there are known several noise attenuators that can be installed in an air-conditioning duct and used in connection with disk valves, for instance. One of them is disclosed in the patent publication US-4667770. This noise attenuator comprises a tube made of some noise attenuating material, in which tube there is installed a helical wall member. The noise attenuator is installed in an air-conditioning duct. The drawback with this attenuator is its complicated structure which leads to high manufacturing costs.

[0007] The Finnish patent application FI-981973 introduces an adjustable noise attenuator to be fitted in an air-conditioning duct. Said attenuator comprises a so-called bracing device, i.e. a perforated cylindrical housing, the outer surface whereof is provided with noise attenuating material. Inside the bracing device, there is arranged a piston compiled of two discs and provided with perforations, and in between said discs there is arranged porous material. The adjusting of the quantity of the air flow in the attenuator is based on the shifting of the perforated piston in the direction of the axis of the bracing device, so that a larger or a smaller part of the air flow is allowed to flow through the bracing device and through the porous material located outside the bracing device. The noise attenuator is installed in between the air-conditioning duct outlet and the connecting box.

[0008] The patent publication US-5 696 361 describes a multi-duct sound attenuator comprising an outer casing and a plurality of ducts made of stainless steel, wherein the space between the ducts is filled with sound absorbing material.

[0009] A drawback with the above described noise attenuator is the complexity of the structure as well as the space required by the installation thereof, particularly the space required by the pull-out member of the manual control device. Moreover, it is pointed out that the noise attenuator is primarily designed to be installed in between an air-conditioning duct and a connecting box.

[0010] The object of the present invention is to eliminate the drawbacks connected to the above described air-conditioning duct adjusting elements and/or noise attenuators. Another object of the invention is to realize a new air-conditioning duct attenuator.

[0011] In order to realize this, the attenuator according to the invention is characterized by what is specified in claim 1.

[0012] The method according to the invention for manufacturing the attenuator is characterized by what is specified in claim 10.

[0013] Preferred embodiments of the invention are characterized by what is specified in the dependent claims.

[0014] An advantage of the air-conditioning duct according to the invention is that thereby the quantity of the air flowing through the air-conditioning duct can be adjusted precisely to a desired magnitude, and simultaneously it effectively attenuates any noises created in the air-conditioning duct and/or carried through it. Hence another advantage of the invention is that there is no need to install a separate noise attenuator in the air-conditioning duct in the vicinity of said attenuator.

[0015] Another advantage of the invention is that in addition to precisely adjusting the magnitude of the air flowing through, the invention also functions as a measuring device in order to define the pressure difference and flowing rate.

[0016] Yet another advantage of the invention is its simplicity of structure and the limited number of separate components. Thus the attenuator according to the invention is economical to manufacture.

[0017] Further, an advantage of the invention is that it can be installed in an air-conditioning duct with a rigid shell without separate installation elements. The diameter of the attenuator can be defined so that it can be attached to the air-conditioning duct by means of friction, without separate fastening members.

[0018] Yet another advantage of the invention is that several attenuators according to the invention can be arranged adjacently and/or successively, either at the same spot in the air-conditioning duct or spaced apart. This improves noise attenuation in the air-conditioning ducts and/or reduces the air flow pressure in several steps between the separate parts of the air-conditioning duct system.

[0019] A particular advantage of the invention is that it is a versatile and user-friendly device that can be fitted in many different spots in an air-conditioning duct system by simple steps and without any proper changes in the duct system. Thereby it is possible to replace, at least partly, the pressure reducing boxes or corresponding elements in inlet air ducts.

[0020] Yet another advantage of the invention is that it can be installed both in the inlet air duct and in the exhaust air duct of a room space. A particular advantage in such an application is that the connecting of the air-conditioning duct to room space can be realized for example by means of a cover plate that matches the interior decoration. In principle, the visual design of the cover plate can be chosen freely; the only prerequisite is that in connection with it, there are provided one or several apertures for the air flow.

[0021] The invention is explained in more detail with reference to the appended drawings, where

figure 1

is a front-view illustration of an attenuator according to the invention,

figure 2a

illustrates the attenuator of figure 1, seen along the section A - A; and

figure 2b

illustrates, in cross-section, plugs that can be fitted in the flow apertures of the attenuator of figure 1,

figure 3

illustrates, in cross-section, an attenuator according to the invention as installed in an air-conditioning duct,

figure 4

illustrates the embodiment of figure 3, seen in the transversal section B - B;

figure 5

illustrates the embodiment of figure 3, seen at the front, along the section C - C,

figure 6a

is a schematical illustration of the manufacturing process of the attenuator according to the invention, seen from above, and

figure 6b

illustrates the manufacturing of the attenuator, seen from the side.

[0022] An advantageous attenuator 10 according to the invention, figures 1, 2a and 2b, comprises a housing 1, realized of a porous, sound-absorbing and resilient material. In shape, the housing 1 is advantageously cylindrical. In the housing 1, there is arranged a number of flow apertures 2; 2¹, 2², 2³ that are parallel to the housing shell la and simultaneously to the longitudinal axis E - E of the housing 1. In shape, the flow apertures 2; 2¹, 2², 2³ are advantageously cylindrical.

[0023] The housing 1 is realized for instance of one of the following materials or of a combination of these: open cell and/or closed cell foam plastic, such as polyether or polyester foam plastic, mineral wool or glass wool, pressed rag and felt. At least as regards the shell la of the housing 1, it must be made of a resilient material, so that it is supported and advantageously compressed against the inner surface 4a of the air-conditioning duct, when it is fitted in the air-conditioning duct.

[0024] In cross-section, the housing 1 is similar to the air-conditioning duct 4 where it should be fitted in. The housing 1 is often circular in cross-section, i.e. the housing 1 is cylindrical, when the air-conditioning duct is a round tube in cross-section, as is illustrated for example in figures 3 and 4. However, the cross-section of both the housing and the air-conditioning duct can likewise represent some other geometrical shape, such as an ellipse, parallelogram, square, polygon or a combination of these.

[0025] Advantageously the diameter d of the housing 1 is slightly larger than the corresponding diameter D of the air-conditioning duct 4. Now the attenuator 10 is installed in the air-conditioning duct 4 for example by simply inserting it in the duct through the open inlet or outlet end, whereafter it expands and is pressed in position in the duct 4, against the inner wall 4a of said duct. In that case the housing 1 of the attenuator 10 remains in place in the duct 4 by means of friction, and it does not need any particular fastening means.

[0026] The length L of the housing 1 of the attenuator 10 is advantageously within the range of 15 - 50 mm. Several attenuators of this type can be placed in succession, for example so that they are in contact, apertures matching. It also is possible to leave suitable intervals in between. The noise attenuation properties of a described attenuator group are better than those of one single attenuator.

[0027] The number of the apertures 2; 2¹, 2², 2³ of the attenuator 10 is advantageously 3 - 10. The apertures 2 are arranged in the housing 1 at suitable intervals. In case the apertures 2 are equal in size, as is the case in the drawings, they are advantageously arranged symmetrically and evenly with respect to the central point or central axis on the transversal surface of the housing 1, i.e. on the surface that is perpendicular to the air flow in the air-conditioning duct.

[0028] In the embodiments illustrated in the drawings, the apertures 2; 2¹, 2², 2³ of the attenuator 10 are equally large holes with circular cross-sections. However, the apertures 2; 2¹, 2², 2³ of the attenuator can also be realized so that they are different in size, and even different in cross-section.

[0029] In this embodiment, the attenuator 10 also includes at least one plug 3, most advantageously a number of plugs 3; 3¹, 3², 3³. The shape and measures of the cross-section of each plug 3 essentially correspond to those of the flow apertures 2; 2¹, 2², 2³ provided in the housing 1, wherein the plug 3; 3¹, 3², 3³ can be fitted. Because the flow apertures 2; 2¹, 2², 2³ are advantageously cylindrical in shape, the plugs 3; 3¹, 3², 3³ are advantageously cylindrical in shape, too.

[0030] Each plug 3; 3¹, 3², 3³ is realized of porous, sound-absorbing material. Most advantageously each plug 3; 3¹, 3², 3³ is realized of the same porous, sound-absorbing and advantageously resilient material as the housing 1.

[0031] In a preferred embodiment, the attenuator 10 according to the invention is realized so that a piece corresponding to the flow aperture 2; 2¹, 2², 2³ is removed of the housing, and said piece is turned into a plug 3; 3¹, 3², 3³ that fits in the respective aperture. Figures 2a and 2b illustrate an embodiment of this type. In that case the diameter da2 of the plug 3; 3¹ is essentially equal to the diameter dal of the respective flow aperture 2; 2¹.

[0032] The flow apertures 2; 2¹, 2², 2³ and the corresponding plugs 3; 3¹, 3², 3³ arranged in the housing 1 of the attenuator 10 are preferably cylindrical.

[0033] The quantity of the air flow in the attenuator 10 is adjusted as follows. When the quantity of the air flow should be reduced, one or several plugs 3; 3¹, 3², 3³ at a time are inserted in the corresponding flow apertures 2; 2¹, 2², 2³ provided in the housing 1. Respectively, a larger air flow can be realized by removing the plug 3; 3¹, 3², 3³ from one or several apertures 2; 2¹, 2² 2³. Thus the air flow in the air-conditioning duct 4 that is provided with the attenuator 10 can be adjusted in steps.

[0034] The flow aperture 2; 2¹, 2², 2³ is arranged to function as the air flow measuring spot. A precise adjusting of the air flow magnitude is achieved by measuring in advance the air flow magnitude with various numbers of open flow apertures 2; 2¹, 2², 2³ in the housing 1. The measuring results are advantageously arranged in tables; on the basis of said tables, the desired limits for adjusting the air flow magnitudes can be set in advance, as well as the air quantities that should be increased and/or reduced step by step in each embodiment. On the basis of the obtained measurement results, the number of required open and closed flow apertures 2; 2¹, 2², 2³ per the desired air flow magnitude can be looked up in the table, and the adjustments can be respectively altered by adding or removing plugs 3; 3¹, 3², 3³.

[0035] The shape of the orifice of the air-conditioning duct, in which the air-conditioning duct attenuator according to the invention is installed, does not have to be the same as in that spot of the air-conditioning duct where the attenuator 10 is installed, but it can be shaped according to the needs of the situation. Thus the air or cover plate 8 covering the orifice of the air-conditioning duct 4 can be designed and installed in a way that is esthetically suitable. The only requirement for the cover plate 8 is that the air flow must be allowed to pass fairly freely through the holes provided therein, or around its edge or edges.

[0036] The attenuator 10 according to the invention is advantageously manufactured by utilizing a cutting water jet, as is illustrated in figures 6a and 6b. The housing blank 6 is cut of a porous plate-like, sound-absorbing material 5, by a high-pressure water jet 7. The housing blank 6 is in turn made into an attenuator 10 by cutting, in a corresponding fashion, flow apertures 2; 2¹, 2², 2³ at predetermined spots of the housing blank 6. Moreover, said flow apertures are preferably cut so that the pieces that are cut out of the flow apertures 2; 2¹, 2², 2³ constitute plugs 3; 3¹, 3², 3³ that fit in said apertures. It is an advantage of the manufacturing method that the plugs 3; 3¹, 3², 3³ are thus manufactured of the same plate as the housing 1. Another advantage is that the manufacturing process is rapid and the final product is well-made and properly finished.

Claims

1. A sound attenuator that can be installed in connection with an air-conditioning duct, which attenuator (10) includes a housing (1) which is realized of a porous, sound-absorbing and resilient material, and that in said housing, there is arranged a number of flow apertures (2; 2¹, 2², 2³) in parallel to the housing shell (1a), the shape and measures of the cross-section of said housing (1) being arranged to correspond to the cross-section of the air-conditioning duct (4) in which the attenuator (10) should be fitted, so that the shell (1a) of the air-conditioning duct is supported, and advantageously expanded and compressed, against the inner surface of the air-conditioning duct (4a), characterized in that the attenuator (10) also includes at least one plug (3; 3¹, 3², 3³) with a cross-sectional shape and measures that essentially correspond to those of the respective flow aperture (2; 2¹, 2², 2³) provided in the housing (1), in which flow aperture the plug (3; 3¹, 3², 3³) can be inserted when adjusting the magnitude of the air flow in the air-conditioning duct (4) where the air-conditioning duct attenuator should be fitted in.

2. A sound attenuator according to claim 1, characterized in that the flow apertures (2; 2¹, 2², 2³) are arranged to function as the air flow measurement point.

3. A sound attenuator according to claim 1 or 2, characterized in that the plug (3; 3¹, 3², 3³) is realized of the same porous, sound-absorbing and resilient material as the housing (1).

4. A sound attenuator according to claim 3, characterized in that a piece corresponding to the flow aperture (2; 2¹, 2², 2³) is removed of the housing (1), and that said piece is made into a plug (3; 3¹, 3², 3³) that fits in said aperture.

5. A sound attenuator according to any of the preceding claims, characterized in that the number of the apertures (2; 2¹, 2², 2³) is 3 - 10.

6. A sound attenuator according to any of the preceding claims 1 - 5, characterized in that the length (L) of the housing (1) is between 15-50 mm.

7. A sound attenuator according to any of the preceding claims, characterized in that the flow apertures (2; 2¹, 2², 2³) and the respective plugs (3; 3¹, 3², 3³) are cylindrical in shape.

8. A sound attenuator according to any of the preceding claims, characterized in that the porous, sound-absorbing material is advantageously one of the following materials or a combination thereof: open cell and/or closed cell foam plastic, such as polyether and/or polyesther foam plastic, mineral wool or glass wool, pressed rag and felt.

9. A method for manufacturing an attenuator that can be installed in connection with an air-conditioning duct (4), characterized in that a housing blank (6) is cut from a plate-like, porous and sound-absorbing material (5) by a high-pressure water jet (7), which housing blank (6) is in turn made into an attenuator (10) by cutting, in corresponding fashion, flow apertures (2; 2¹, 2², 2³) at predetermined spots of the housing blank (6), so that the pieces that are cut off to form the flow apertures constitute plugs (3; 2¹, 2², 2³) that fit in said apertures.

Ansprüche

1. Schalldämpfer, der in Verbindung mit einem Klimaanlagenkanal eingebaut werden kann, wobei der Dämpfer (10) ein Gehäuse (1) umfasst, das aus einem porösen, Schall absorbierenden und elastischen Material verwirklicht ist, und wobei in dem Gehäuse eine Anzahl von Strömungsöffnungen (2; 2¹, 2², 2³) parallel zu der Gehäusehülle (1a) angeordnet ist, wobei die Form und Abmessungen des Querschnitts des Gehäuses (1) derart eingerichtet sind, dass sie dem Querschnitt des Klimaanlagenkanals (4), in den der Dämpfer (10) eingepasst werden soll, entsprechen, so dass die Hülle (1a) des Klimaanlagenkanals gegen die Innenfläche des Klimaanlagenkanals (4a) abgestützt und vorteilhaft ausgedehnt und zusammengedrückt ist, dadurch gekennzeichnet, dass der Dämpfer (10) auch mindestens einen Stopfen (3; 3¹, 3², 3³) mit einer Querschnittsform und Querschnittsabmessungen aufweist, die im Wesentlichen jenen der jeweiligen Strömungsöffnung (2; 2¹, 2², 2³), die in dem Gehäuse (1) vorgesehen sind, entsprechen, wobei der Stopfen (3; 3¹, 3², 3³) in die Strömungsöffnung eingesetzt werden kann, wenn die Größe der Luftströmung in dem Klimaanlagenkanal (4), in den der Klimaanlagenkanaldämpfer eingepasst werden soll, eingestellt wird.

2. Schalldämpfer nach Anspruch 1,
dadurch gekennzeichnet, dass
die Strömungsöffnungen (2; 2¹, 2², 2³) derart eingerichtet sind, dass sie als Luftströmungs-Messpunkt wirken.

3. Schalldämpfer nach Anspruch 1 oder 2,
dadurch gekennzeichnet, dass
der Stopfen (3; 3¹, 3², 3³) aus dem gleichen porösen, Schall absorbierenden und elastischen Material wie das Gehäuse (1) verwirklicht ist.

4. Schalldämpfer nach Anspruch 3,
dadurch gekennzeichnet, dass
ein Stück, das der Strömungsöffnung (2; 2¹, 2², 2³) entspricht, von dem Gehäuse (1) entfernt ist, und dass das Stück zu einem Stopfen (3; 3¹, 3², 3³) hergestellt ist, der in die Öffnung passt.

5. Schalldämpfer nach einem der vorhergehenden Ansprüche,
dadurch gekennzeichnet, dass
die Anzahl der Öffnungen (2; 2¹, 2², 2³) 3 - 10 beträgt.

6. Schalldämpfe nach einem der vorhergehenden Ansprüche 1-5, dadurch gekennzeichnet, dass die Länge (L) des Gehäuses (1) zwischen 15 - 50 mm beträgt.

7. Schalldämpfer nach einem der vorhergehenden Ansprüche,
dadurch gekennzeichnet, dass
die Strömungsöffnungen (2; 2¹, 2², 2³) und die jeweiligen Stopfen (3; 3¹, 3², 3³) eine zylindrische Form aufweisen.

8. Schalldämpfer nach einem der vorhergehenden Ansprüche,
dadurch gekennzeichnet , dass
das poröse, Schall absorbierende Material vorteilhafterweise eines der folgenden Materialien oder eine Kombination davon ist: offenzelliger und/oder geschlossenzelliger Schaumkunststoff wie etwa Polyether und/oder Polyesterschaumkunststoff, Mineralwolle oder Glaswolle, gepresstes Tuch und Filz.

9. Verfahren zum Herstellen eines Dämpfers, der in Verbindung mit einem Klimaanlagenkanal (4) eingebaut werden kann,
dadurch gekennzeichnet, dass
ein Gehäuserohling (6) aus einem plattenartigen, porösen und Schall absorbierenden Material (5) durch einen Hochdruck-Wasserstrahl (7) geschnitten wird, wobei der Gehäuserohling (6) wiederum zu einem Dämpfer (10) hergestellt wird, indem in entsprechender Weise Strömungsöffnungen (2; 2¹, 2², 2³) an vorbestimmten Punkten des Gehäuserohlings (6) geschnitten werden, so dass die Stücke, die herausgeschnitten werden, um die Strömungsöffnungen zu erzeugen, Stopfen (3; 2¹, 2², 2³) bilden, die in die Öffnungen passen.

Revendications

1. Atténuateur acoustique susceptible d'être installé en association avec un conduit de climatisation lequel atténuateur (10) comprenant un logement (1) qui est réalisé en matériau poreux, absorbant phonique et élastique, et un certain nombre d'ouvertures de flux (2 ; 2¹, 2², 2³) étant disposées dans ledit logement parallèlement à l'enveloppement du logement (1a), les forme et dimensions de la section transversale dudit logement (1) étant adaptées pour correspondre à la section transversale du conduit de climatisation (4) dans lequel l'atténuateur (10) doit être installé de telle sorte que l'enveloppe (1a) du conduit de climatisation soit supportée et de façon avantageuse dilatée et compressée contre la surface intérieure du conduit de climatisation (4a), caractérisé en ce que l'atténuateur (10) comprend également au moins un bouchon (3 ; 3¹, 3², 3³) de forme et de dimensions en section qui correspondent sensiblement à celles de l'ouverture de flux respective (2 ; 2¹, 2², 2³) prévue dans le logement (1), le bouchon (3 ; 3¹, 3², 3³) pouvant être inséré dans l'ouverture de flux lors du réglage de l'amplitude du flux d'air dans le conduit de climatisation (4) où l'atténuateur du conduit de climatisation est prévu pour être installé.

2. Atténuateur acoustique selon la revendication 1, caractérisé en ce que les ouvertures de flux (2 ; 2¹, 2², 2³) sont disposées pour fonctionner comme point de mesure du flux d'air.

3. Atténuateur acoustique selon la revendication 1 ou 2, caractérisé en ce que le bouchon (3 ; 3¹, 3², 3³) est réalisé dans le même matériau poreux absorbant acoustique et élastique que le logement (1).

4. Atténuateur acoustique selon la revendication 3, caractérisé en ce qu'une pièce correspondant à l'ouverture de flux (2 ; 2¹, 2², 2³) est retirée du logement (1), et en ce que ladite pièce est faite en un bouchon (3 ; 3¹, 3², 3³) qui s'ajuste dans ladite ouverture.

5. Atténuateur acoustique selon l'une quelconque des revendications précédentes, caractérisé en ce que le nombre d'ouvertures (2 ; 2¹, 2², 2³) est compris entre 3 et 10.

6. Atténuateur acoustique selon l'une quelconque des revendications précédentes 1 à 5, caractérisé en ce que la longueur (L) du logement (1) est comprise entre 15 et 50 mm.

7. Atténuateur acoustique selon l'une quelconque des revendications précédentes, caractérisé en ce que les ouvertures de flux (2 ; 2¹, 2², 2³) et les bouchons respectifs (3 ; 3¹, 3², 3³) ont une forme cylindrique.

8. Atténuateur acoustique selon l'une quelconque des revendications précédentes, caractérisé en ce que le matériau poreux et absorbant acoustique est avantageusement l'un des matériaux suivants ou une combinaison entre ceux-ci : matière synthétique alvéolaire à alvéole ouverte ou fermée telle que une mousse de polyéther ou polyester, de la laine minérale ou de la laine de verre, du chiffon pressé ou du feutre.

9. Procédé de fabrication d'un atténuateur susceptible d'être installé en association avec un conduit de climatisation (4) caractérisé en ce qu'une ébauche de logement (6) est découpée à partir d'un matériau (5) en forme de plaque poreux et absorbant acoustique par un jet d'eau à haute pression (7), ladite ébauche (6) de logement étant à son tour transformé en un atténuateur (10) par découpe, dans une forme complémentaire, d'ouvertures de flux (2 ; 2¹, 2², 2³) à des endroits prédéterminés de l'ébauche (6) de logement de telle sorte que les pièces qui sont découpées pour former les ouvertures de flux constituent des bouchons (3 ; 2¹, 2², 2³) qui s'ajustent dans lesdites ouvertures.

Drawing