JP2531054B2 - Air conditioning duct noise attenuator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a hall, an audiovisual room,
The present invention relates to an air-conditioning duct noise attenuating device for a recording studio and various other structures, which is capable of effectively reducing the noise propagating in the duct with a simple configuration.

[0002]

2. Description of the Related Art In designing halls, audio-visual rooms, recording studios, etc., sufficient measures must be taken against noise intruding through air-conditioning ducts as well as sound insulation structures on wall surfaces.

[0003] In the conventional design of a building, the building design and the equipment design are performed separately. Therefore, as a noise reduction measure for the air conditioning duct, the iron plate duct may be passed through the duct space provided in the building design as it is, or the duct space may be used. A damping device (sound-absorbing elbow, sound-absorbing chamber, muffler-type silencer, etc.) was installed inside to secure the required volume reduction.

FIG. 2 shows a conventional noise reduction measure for an air conditioning duct. In this building 10, in addition to the main space such as a stage, a room, and a corridor, a duct space 14 that is surrounded and enclosed by a boundary wall 12 is configured, and an air conditioning duct 16 made of a steel plate duct is formed in the space. 18 is passed through a hole 19 formed in the boundary wall 12. Duct space 1
In FIG. 4, a straight pipe type silencer (muffler type silencer) 20 is inserted in the air conditioning duct 16. The silencer 20 has a cross-sectional area S larger than the cross-sectional area ρ of the air conditioning duct 16 and is lined with a sound absorbing material, so that the noise propagating in the air conditioning duct 16 due to expansion-type sound reduction and absorption-type sound absorption. Reduce the sound.

In the duct space 14, two stages of sound absorbing elbows 22 and 24 are inserted in the air conditioning duct 18. The sound absorbing elbows 22 and 24 each bend the flow path at a right angle and are lined with a sound absorbing material to reduce the noise propagated in the air conditioning duct 18 by the reflection due to the right angle bending and the sound absorption by the lined sound absorbing material.

In the sound reduction by the silencer 20, the volume reduction is proportional to S / ρ. Therefore, in order to increase the volume reduction,
The silencer 20 must have a large cross-sectional area, and in order to obtain the necessary volume reduction, the silencer 20 becomes large in size, the cost becomes high, and the duct space 14 needs to be wide. In addition, the amount of attenuation of low-pitched sound is small, and particularly in the case of high-pitched sound type, the amount of attenuation in reduction is only about 5 to 10 dB. In addition, the experimental data (catalog value) cannot be secured at the construction site.
It was easily affected by the installation conditions.

In the sound reduction by the sound absorbing elbows 22 and 24, the sound reduction volume is small, and in particular, only a few dB can be obtained. Further, it was not easy to install the sound absorbing elbows 22 and 24 on the air conditioning duct 18 in the duct space 14.

Therefore, an air conditioning duct noise attenuating device which solves such a problem and has a large noise reduction effect with a simple structure and a small installation space is proposed in Japanese Patent Application No. Proposed as 86735.

This is a material in which an air-conditioning duct is piped through a portion surrounded by a boundary wall of a building, and a part or all of the duct positioned in the surrounding wall of the boundary wall is acoustically almost transparent. It is composed of.

That is, this air-conditioning duct noise attenuator realizes a sound-reducing structure by fusing architectural design and equipment design, and is surrounded by a boundary wall of a building such as a duct space or dead space that is provided in advance. The sound is reduced using the space itself. That is, the air that has flowed through the duct passes through the portion that is made of a material that is acoustically almost transparent, but the sound that has propagated in the duct is almost transmitted through the portion surrounded by the field wall. Since the portion made of a flexible material is leaked out of the duct and diffused, expansion type noise reduction is performed there. In this case, the volume reduction is proportional to [the cross-sectional area of the diffusion portion] / [the cross-sectional area of the duct], but the cross-sectional area of the portion that causes the diffusion is the cross-sectional area of the boundary wall surrounding portion itself, so the conventional silencer (Fig. Code 2
Compared with 0), it is possible to secure an extremely wide cross-sectional area, to obtain a large volume reduction, and in particular, to secure a large amount of attenuation in the bass range as compared with the conventional one.

Further, since a part of the duct only needs to be made of an acoustically almost transparent material (for example, glass wool duct), it can be constructed easily and easily, and the installation space can be small.

Further, even if there are a plurality of ducts (a plurality of ducts), the same volume reduction as in the case where they are arranged independently is obtained for each duct. Therefore, even if the number of ducts increases, the size of the installation space remains the same. However, the more strains there are, the more effective it is.

[0013]

In an air conditioning system, there are a supply system that sends cold (or warm) air and a return system that sucks indoor air during cooling and heating. In conventional air conditioning systems, separate noise reduction measures have been taken for the supply system and the return system. Therefore, a large space is required to arrange the noise damping means. This invention intends to provide an air-conditioning duct noise attenuating device which utilizes the air-conditioning duct noise attenuating device of the above-mentioned Japanese Patent Application No. 2-86735 so that noise suppression measures for supply system and return system can be performed in the same space. is there.

[0014]

DISCLOSURE OF THE INVENTION The present invention is directed to a boundary wall surrounding portion surrounded by a boundary wall of a building, and a part of a duct which is piped through the boundary wall surrounding portion and is located in the boundary wall surrounding portion. Alternatively, it is provided with a supply system air conditioning duct which is entirely made of an acoustically almost transparent material, and a return system air conditioning duct which has the field wall surrounding portion as a part of the duct. .

[0015]

According to the present invention, the noise attenuation of the supply system can be achieved by utilizing the air-conditioning duct noise attenuating device of Japanese Patent Application No. 2-86735. Further, the return system uses the space itself of the field wall surrounding portion where the supply system air conditioning duct noise attenuator is arranged as a part of the duct to achieve noise attenuation by expansion type noise reduction.

According to this structure, the noise damping device can be disposed in the same space in the supply system and the return system, so that the space can be saved.

[0017]

FIG. 1 shows an embodiment of the present invention. This building 30 is provided in advance for duct piping, or is a dead space and is surrounded by a boundary wall 32 (a concrete wall or a slab). A so-called duct space 31 (boundary wall surrounding portion) is configured, and four supply system air conditioning ducts 34 to 37 are passed through it.

In the supply system air conditioning ducts 34 to 37, the portions 34a to 37a outside the duct space 31 (generally connected to the main space such as a room or stage) are iron plate ducts. The opening end portion is fixed to the outer surface of the boundary wall 32 by bolting or the like so as to communicate with the holes 40 of the same cross-sectional area formed in the left and right boundary walls 32.

Further, in the air conditioning ducts 34 to 37, portions 34a to 37a inside the duct space 31 are glass wool ducts, and bolts are attached to the inner surface of the boundary wall 32 so that the open ends thereof communicate with the holes 40. It is fixed by a stopper. The glass wool ducts 34b to 37b are formed by forming glass wool boards having relatively hard seats into a pipe shape, and in some cases, an aluminum cover (which is almost transparent for bass) may be provided on the outer cover. This glass wool duct is almost impermeable to air,
It is acoustically almost transparent.

Flowing air to each of the main spaces flows through the air conditioning ducts 34 to 37. In addition, noise from blowers and the like provided in the supply system and the return system also propagates through them.

The return air conditioning duct 50 is constructed by hermetically inserting the iron plate duct 50a into the holes 52 formed in the upper and lower boundary walls 32 and fixing it to the boundary wall 32 with bolts or the like.
As a result, a return-type air flow path is configured with the duct space 31 as a part of the duct.

According to the configuration of FIG. 1 described above, in the supply system, the air flowing in the air conditioning ducts 34 to 37 passes through the glass wool ducts 34b to 37b as it is. At this time, the glass wool ducts 34b to 37b function as a heat insulating material for the flowing cold (or warm) air. In addition, the noise that has propagated through the air conditioning ducts 34 to 37 is not limited to the glass wool duct 34b in the duct space 31.
Leakage through the walls of ~ 37b and diffuses into the duct space 31. Due to this diffusion, expansion type sound reduction is performed. Further, absorption type sound absorption is also performed by the glass wool ducts 34b to 37b themselves.

In the return system, the air and noise flowing in the air conditioning duct 50 diffuse into the duct space 31, and expansion-type noise reduction is performed at this time. At this time, since the glass wool ducts 34b to 37b serve as a partition plate in a so-called muffler structure, more effective sound absorption is performed, and glass wool or the like need not be lined on the inner wall of the duct space 31. The amount can also be reduced. Then, the air is discharged from the lower air conditioning duct 50.

FIG. 3 conceptually shows the noise reduction operation by the expansion type noise reduction for one air conditioning duct 34 of the supply system of FIG. Assuming that the cross-sectional area of the duct space 31 is S ₀ and the cross-sectional area of the air conditioning duct 34 is ρ ₀ , expansion-type noise reduction provides a volume reduction proportional to S ₀ / ρ ₀ . S
_{Since 0} can be set to be much larger than the cross-sectional area S of the conventional silencer 20 (FIG. 2), a large volume reduction can be obtained especially in the bass range. Further, with respect to sounds in the midrange and treble ranges, the material itself of the glass wool ducts 34b to 37b can be effectively absorbed by being a sound absorbing material.

Further, even if the number of systems (the number of ducts) is increased, the same volume reduction as in the case of arranging them independently can be obtained for each system. Therefore, the larger the number of systems, the greater the noise reduction effect. In other words, assuming that the volume reduction when only one duct is arranged is A, the total volume reduction when n ducts are arranged is nA, which is 1 per unit as compared with the case where only one duct is arranged. An equivalent volume reduction is obtained for each duct with a duct space of / n.

FIG. 4 shows an air conditioning duct 5 of the return system shown in FIG.
0 is a conceptual illustration of the noise reduction operation by expansion type noise reduction. When the cross-sectional area of the duct space 31 is S ₁ and the cross-sectional area of the air conditioning duct 50 is ρ ₁ , a volume reduction proportional to S ₁ / ρ ₁ can be obtained by the expansion type sound absorption. Since S ₁ can be made much larger than the cross-sectional area S of the conventional silencer 20 (FIG. 2), a large volume reduction can be obtained especially in the low sound range.
Further, with respect to sounds in the midrange and treble ranges, the material itself of the glass wool ducts 34b to 37b can be effectively absorbed by being a sound absorbing material.

Due to the above sound-absorption function, according to the embodiment shown in FIG.
Low noise of (noise criterion) -15 or less can be easily realized.

If a sound absorbing material such as glass wool is lined on the inner wall surface of the duct space 31 shown in FIG.
With the return system, the sound reduction effect can be enhanced.

[0029]

[Modification] In the above-described embodiment, the supply system and the air conditioning ducts 34 to 37 are constituted by the glass wool ducts 34b to 37b over the entire duct space 31, but as shown in FIG. 34-37 can also be constituted by glass wool ducts 34b-37b.

Further, in the above embodiment, the inner diameters of the glass wool ducts 34b to 37b are made substantially the same as the inner diameters of the iron plate ducts 34b to 37b, but they do not necessarily have to be the same inner diameter.

Further, in the above-mentioned embodiment, the supply system acoustically almost transparent material is glass wool, but rock wool or other various materials substantially impermeable to air and acoustically substantially transparent are used. be able to.

[0032]

As described above, according to the present invention, the noise attenuating device can be disposed in the same space in the supply system and the return system, so that the space can be saved. Further, as shown in the above embodiment, if the acoustically almost transparent material forming the supply system is made of glass wool or the like, a sound absorbing effect can be obtained in this part in both the supply system and the return system.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a conventional device.

FIG. 3 is a conceptual diagram showing a sound reducing action in the supply system of the apparatus of FIG.

FIG. 4 is a conceptual diagram showing a sound reduction effect in the return system of the apparatus of FIG.

FIG. 5 is a vertical sectional view showing another embodiment of the supply system according to the present invention.

[Explanation of symbols]

30 Buildings 31 Duct Space (Bounding Wall Surrounding Part) 32 Boundary Wall 34 to 37 Supply Air Conditioning Duct (Duct Main Body) 34b to 37b Glass Wool Duct (Acoustic Acoustically Transparent Material) 50 Return Air Conditioning Duct

Claims (1)

(57) [Claims] 1. A boundary wall surrounding portion surrounded by a boundary wall of a building, and a part or all of a duct which is piped through the boundary wall surrounding portion and is located in the boundary wall surrounding portion is substantially acoustically transparent. An air conditioning duct noise attenuating apparatus comprising: a supply air conditioning duct made of a flexible material; and a return air conditioning duct having the boundary wall surrounding portion as a part of the duct.