JPH0620990U - silencer - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a silencer that is easy to construct, easy to maintain, and has excellent sound absorption characteristics. [Structure] A plurality of cylindrical sound absorbing cylinders 13 are appropriately arranged in a duct 12. The sound absorbing cylinder preferably has a cylindrical sound absorbing material arranged in a cylindrical protective cylinder. As for the arrangement of the sound absorbing cylinders in the duct, a plurality of sound absorbing cylinders are arranged so as to be perpendicular to and parallel to the air flow direction, or a plurality of sound absorbing cylinders are parallel to the air flow direction. Is preferably arranged so that

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a silencer or silencer provided in the middle of a duct of an air conditioner or the like to prevent noise from a noise source such as a blower.

[0002]

[Prior art]

 Conventionally, the following types of duct silencers are generally used. (1) As shown in FIG. 5 (a), an inner pasting silencer 1 A in which a flat sound absorbing material 3 is pasted on the inner surface of a duct 2. (2) As shown in FIG. 5 (b), a split silencer 1B in which the inside of the duct 2 is divided by parallel core materials 4, and a flat sound absorbing material 3 is attached to the inner surface of the duct and the surface of the core material. (C) As shown in FIG. 5 (c), the duct 2 is vertically and horizontally divided into core members 4 and 5, and a flat sound absorbing member 3 is attached to the inner surface of the duct and the surface of the core member to attach the flat sound absorbing member 3C. .

[0003]

[Problems to be solved by the device]

 However, all such conventional silencers have the following problems. In other words, (1) Since the inner-attachment silencer 1A has the sound absorbing material internally attached to the entire inner surface of the duct, it is necessary to cut the flat sound absorbing material along the inner surface of the duct to adjust the dimensions. However, the workability is poor, and in addition, there are many wastes in the sound absorbing material due to deformation of the sound absorbing material (material with odd dimensions). Further, since the sound absorbing material is arranged only on the outer peripheral portion of the air passage, the sound absorbing effect is poor. (2) The split-type silencer 1B and the cell-type silencer 1C have a better sound absorbing effect than the inner-attachment type silencer 1A, but the workability is further deteriorated, and the abnormal shape of the sound absorbing material is generated more frequently. Further, there is a drawback that it may be difficult to remove due to the rust of the fixing metal fittings during the maintenance period.

The present invention has been made in view of the above conventional problems, and an object thereof is to provide a silencer that is easy to construct and easy to maintain, unlike the conventional silencer.

[0005]

[Means for Solving the Problems]

 The present inventor has found that a silencer with excellent workability can be constructed by appropriately arranging a plurality of cylindrical sound absorbing tubes in the duct, and completed the present invention.

[0006] That is, the gist of the present invention is a silencer characterized in that a plurality of cylindrical sound absorbing cylinders are provided in a duct at intervals.

The sound absorbing cylinder used here is preferably one in which a cylindrical sound absorbing material is arranged in a cylindrical protective cylinder from the viewpoint of workability and sound absorbing properties.

In the silencer of the present invention, the arrangement of the plurality of sound absorbing cylinders provided in the duct is not particularly limited, but it is preferable to adopt one of the following two ways.

(1) A plurality of sound absorbing cylinders are arranged in a plurality of stages in the air flow direction in the duct, and in each stage, the sound absorbing cylinders are arranged at right angles to the air flow direction and parallel to each other. The silencer with this arrangement is also called a "split cell mixed type". In the case of this arrangement, it is preferable to arrange the sound absorbing cylinder immediately behind the sound absorbing cylinder in the front stage so as to be at a right angle when viewed in the direction of the air flow.

(2) A plurality of sound absorbing cylinders are arranged parallel to the air flow direction in the duct. The silencer based on this arrangement should be called "pseudo cell mixed type". In the case of this arrangement, it is preferable that the cylindrical sound absorbing material has a hollow structure having reflectors having no air permeability at both ends.

[0011]

[Action]

 Since the silencer with the above-mentioned configuration has a plurality of sound absorbing cylinders arranged at intervals in the duct, it is only necessary to mount the sound absorbing cylinders in the duct by an appropriate means, and the construction is easy and wasteful sound absorbing material. Does not occur. Further, in this silencer, sound is absorbed by a plurality of sound absorbing cylinders arranged in the duct, but since the sound absorbing cylinders are arranged at intervals, the resistance to the air flow in the duct is small, and Since the contact area with the air flow is large, the sound absorption efficiency is good.

Here, if the sound absorbing cylinder is provided with a cylindrical sound absorbing material in a cylindrical protective cylinder, there is no specificity of the direction in the axial direction and the circumferential direction. There is no need, and construction becomes even easier. In addition, since the protective cylinder covers and protects the sound absorbing material, it is easy to handle during transportation and construction.

In the split cell mixed type silencer, when the sound absorbing cylinder is viewed in the sound traveling direction (air flow direction), the sound absorbing cylinder is arranged so that its side surface blocks the entire surface of the duct. Reliably enters the side surface of the cylindrical sound absorbing material, and a high sound absorbing effect is obtained.

In the quasi-cell mixed type using the sound absorbing cylinder having the hollow structure having the reflectors at both ends, since the reflector is attached to the front surface (with respect to the traveling direction of the sound) of the sound absorbing cylinder, the sound is absorbed by the sound absorbing cylinder. Incident on the side surface thereof, which increases the contact between the sound wave and the sound absorbing material and enhances the sound absorbing effect. Further, the sound wave incident on the inside of the sound absorbing cylinder is diffusely reflected by the hollow portion inside due to the function of the reflector and comes into contact with the sound absorbing material, whereby the sound is further absorbed. Thus, a high sound absorbing effect can be obtained.

[0015]

【Example】

 FIG. 1 shows a split cell mixed type silencer according to an embodiment of the present invention. (A) is a schematic horizontal sectional view of the silencer, (b) is a schematic vertical sectional view of the silencer, and (c). 8A is a schematic cross-sectional view of the silencer as viewed in the direction of arrow XX in FIG. In FIG. 1, reference numeral 11A indicates the entire silencer. The silencer 11A includes a sound absorbing cylinder 13 having a cylindrical sound absorbing material, which is arranged in the duct 12 at a plurality of intervals. The plurality of sound absorbing cylinders 13 are arranged such that the plurality of sound absorbing cylinders 13 have a plurality of stages in the sound in the duct 12 with respect to the approach direction (the direction of the air flow, that is, the arrow A direction) (7 stages in the embodiment of the drawings). Is provided). Here, the plurality of sound absorbing cylinders 13 forming each stage are arranged at right angles to the direction A of the air flow and parallel to each other, but the sound absorbing cylinders of the stage immediately following the sound absorbing cylinder 13 of the preceding stage. 13 is arranged so as to be a right angle when viewed in the direction of the air flow. That is, the sound absorbing cylinders 13 are horizontally arranged in the first stage located on the most upstream side of the air flow and the third stage, the fifth stage, and the seventh stage downstream thereof, but they are arranged between them. In the second stage, the fourth stage, and the sixth stage, the sound absorbing cylinders 13 are arranged vertically. Further, the sound absorbing cylinders 13 arranged in parallel to each other are arranged such that the sound absorbing cylinders 13 in the subsequent stage are located between the sound absorbing cylinders 13 in the front stage and the sound absorbing cylinders 13 when viewed in the sound entering direction. .

Here, the distance p between the sound absorbing cylinders 13 and the distance d between the steps in each step are determined in consideration of the resistance given to the air flow and the sound deadening efficiency. In addition, it is preferable that the diameter is about twice the diameter of the sound absorbing cylinder 13. Further, the number of stages of the sound absorbing cylinder 13 is not limited to the seven stages shown in the figure, and may be appropriately determined according to the required sound absorbing performance.

FIG. 2 is a schematic perspective view showing the sound absorbing cylinder 13 used in the silencer of FIG. 1, and FIG. 3 is a schematic sectional view showing a part of the sound absorbing cylinder 13 and a mounting mechanism of the sound absorbing cylinder. The sound absorbing cylinder 13 has a breathable cylindrical protective cylinder 15, a hollow cylindrical sound absorbing material 16 provided on the inner surface thereof, and caps 17 attached to both ends thereof. As the protective cylinder 15, it is preferable to use punching metal, wire netting or the like alone or in combination. If the opening ratio of the opening of the protective tube 15 is too small, the sound is reflected and the sound absorption rate is lowered. On the contrary, if it is too large, the strength is lowered and the protective tube cannot serve as a protective tube. Taking these factors into consideration, it is usually selected to be about 25 to 80%.

As the sound absorbing material 16, a material having sound absorbing performance such as glass wool and rock wool can be appropriately used. It is preferable that the outer surface of the sound absorbing material 16 is covered with a thin synthetic resin film for protection. The cap 17 is used to protect the sound absorbing material and to attach the sound absorbing cylinder 13, and is usually made of a metal plate, and the eyebolt 18 is fixed to the center thereof. The cap 17 may be a breathable one (for example, punching metal) or a non-breathable one. The size of the sound absorbing cylinder 13 is not particularly limited, and is determined in consideration of ease of handling, size of the duct, and the like. For example, the sound absorbing cylinder 13 has an outer diameter of 200 to 500 mm and a length of 1 m to 4 m.

The sound absorbing cylinder 13 is fixed by connecting the eye bolt 18 fixed to the cap 17 to the eye bolt 22 on the duct 12 side by the shackle 19, the chain 20, and the shackle 21. The sound absorbing cylinder 13 may be fixed to the duct 12 by using other suitable fixing means instead of using the chain 20. Further, the body of the sound absorbing cylinder 13 may be fixed with a band or the like. It may be fixed at a predetermined position in the duct by using an appropriate fixing means. However, when the chain is used as in the illustrated embodiment, it is possible to easily adjust the space between the sound absorbing cylinders and the space between the sound absorbing cylinders and the inner surface of the duct with a high degree of freedom.

In FIG. 1, in the silencer 11 A having the above-described configuration, the air flow flows in the direction of the arrow A in the duct 12, but the sound absorbing cylinders 13 are arranged with a space therebetween, so that the air flow obstructs the space. Since the sound absorbing cylinder 13 has a cylindrical shape, it has a low resistance to air flow. Therefore, the pressure loss is small, and therefore the energy loss when blowing air is small, and the load on the equipment is small. The noise from the blower and the like travels in the same direction as the air flow, that is, in the direction of arrow A, but these sounds are perpendicular to the axis of the sound absorbing cylinder 13 that is horizontally and vertically arranged in the duct 12. The light is incident in the direction and is absorbed by the sound absorbing material 16 (see FIG. 3). As can be seen from FIG. 1 (c), the sound absorbing cylinder 13 is arranged so as to close almost the entire surface of the inside of the duct 12, so that the sound absorbing effect is great. Thus, the noise transmitted in the duct can be effectively suppressed.

In manufacturing the silencer 11 A having the above structure, it is only necessary to attach the sound absorbing cylinder 13 to a predetermined position in the duct 12 using a chain or the like. Therefore, the workability is extremely good and the construction is easy. In addition, the sound absorbing cylinder 13 having the above-described structure has a high exterior strength, can be rolled and carried, and is extremely lightweight, and thus is easy to handle. For example, when the diameter of the sound absorbing cylinder 13 is 400 mm, the density of the sound absorbing material is 40 kg / m ³ , and the thickness is 50 mm, the weight of the sound absorbing cylinder 13 per 1 m of axial length is about 8 kg. Thus, the silencer 11A is extremely easy to manufacture. In addition, at the time of repair, it is sufficient to remove the sound absorbing cylinder 13 by removing the chain, which facilitates maintenance.

In the above-described embodiment, the sound absorbing cylinder 13 used in the silencer 11A is the one shown in FIGS. 2 and 3, but the sound absorbing cylinder 13 is not limited to this and has a cylindrical shape. It is optional as long as it has a sound absorbing function, and for example, the one disclosed in Japanese Utility Model Laid-Open No. 62-186200 may be used. Further, the shape of the sound absorbing cylinder 13 is not limited to a cylindrical shape, but can be modified such as a square shape.

FIG. 4 shows a pseudo-cell mixed type silencer 11B according to another embodiment of the present invention. (A) is a schematic horizontal sectional view of the silencer, and (b) is a schematic vertical sectional view of the silencer. FIG. 6C is a schematic sectional view of the silencer as seen in the direction of arrow YY in FIG. In FIG. 4, this silencer 11B also has a plurality of sound absorbing cylinders 13 provided with a cylindrical sound absorbing material arranged in the duct 12 at intervals. In the present embodiment, a plurality of sound absorbing cylinders 13 are arranged in the duct. They are arranged in parallel with the direction A of the air flow in 12. The sound absorbing cylinder 13 used here also has the structure shown in FIGS. 2 and 3. However, in the sound absorbing cylinder 13 used for the silencer 11B, it is preferable that the caps 17 at both ends act as reflectors, so that the cap 17 is not breathable (hence, punching metal or the like cannot be used).

Here, the interval p between the sound absorbing cylinders 13 arranged in parallel may be appropriately determined in consideration of the resistance given to the air flow and the sound deadening efficiency. In the embodiment shown in the drawings, the plurality of sound absorbing cylinders 13 arranged in parallel are provided in two stages in the air flow direction, but the number of stages can be appropriately increased or decreased, and the length of the sound absorbing cylinders 13 to be used and required sound absorption It may be set appropriately according to the performance. Further, when the sound absorbing cylinders 13 are provided in a plurality of stages in the air flow direction, the interval D is not limited, but it is usually about 1 m or preferably about 1/4 wavelength of the sound absorbing target frequency.

In this silencer 11 B, since the reflector (cap 17) is attached to the front surface (relative to the traveling direction of sound) of the sound absorbing cylinder 13, sound enters the sound absorbing cylinder 13 from its side surface, It enters the inside through the cylindrical sound absorbing material 16 (see FIG. 3). As a result, the contact between the sound wave and the sound absorbing material is increased, and the sound absorbing effect is enhanced. Further, the sound wave incident on the inside of the sound absorbing cylinder is diffusely reflected by the hollow portion inside the sound absorbing cylinder due to the function of the reflector and comes into contact with the sound absorbing material, whereby the sound is further absorbed. Thus, a high sound absorbing effect can be obtained.

Even when the silencer 11 B is manufactured, since the sound absorbing cylinder 13 only needs to be attached to the duct 12 at a predetermined position, the construction is extremely easy.

The sound absorbing cylinder 13 used for the silencer 11B is not limited to the one having the above-described configuration, and can be changed as appropriate as long as it has a cylindrical shape and a sound absorbing function. However, in order to exhibit a highly efficient sound absorbing effect, it is preferable that the sound absorbing cylinder has a hollow structure and that both ends thereof have a reflector.

[0027]

[Effect of device]

 As described above, the silencer of the present invention has a plurality of sound absorbing cylinders arranged at intervals in the duct.Therefore, simply install the sound absorbing cylinders in the duct by an appropriate means during construction. It has good effects that it is easy to install and does not generate wasteful sound absorbing material, and that in repairing, the sound absorbing cylinder can be removed, which facilitates maintenance.

Further, as shown in the embodiment, when the sound absorbing cylinder is provided with the cylindrical sound absorbing material in the cylindrical protective cylinder, there is no specificity of the direction in the axial direction and the circumferential direction. Sometimes it is not necessary to consider the mounting direction, which makes the construction even easier, and since the protective cylinder covers and protects the sound absorbing material, it is easy to handle during transportation and construction.

[Brief description of drawings]

1A and 1B show a split cell mixed type silencer according to an embodiment of the present invention, wherein FIG. 1A is a schematic horizontal sectional view of the silencer, FIG. 1B is a schematic vertical sectional view of the silencer, and FIG. ) Is a schematic sectional view of the silencer as seen in the direction of arrow XX in (a).

FIG. 2 is a schematic perspective view showing a sound absorbing cylinder 13 used in the silencer of FIG.

FIG. 3 is a schematic cross-sectional view showing a part of the sound absorbing cylinder 13 and a mounting mechanism of the sound absorbing cylinder.

4A and 4B show a pseudo cell mixed type silencer according to a second embodiment of the present invention, wherein FIG. 4A is a schematic horizontal sectional view of the silencer, and FIG. 4B is a schematic vertical sectional view of the silencer. c) shows the silencer with arrow Y in (a)
-Schematic sectional view seen in the Y direction

5A, 5B, and 5C are schematic cross-sectional views showing a conventional silencer.

[Explanation of symbols]

 11A Split cell mixed type silencer 11B Pseudo cell mixed type silencer 12 Duct 13 Sound absorbing tube 15 Protective tube 16 Cylindrical sound absorbing material 17 Cap

Claims (4)

[Scope of utility model registration request] 1. A silencer, characterized in that a plurality of cylindrical sound absorbing cylinders are provided in the duct at intervals. 2. The silencer according to claim 1, wherein the sound absorbing cylinder has a cylindrical protective cylinder and a cylindrical sound absorbing material provided inside thereof. 3. A plurality of the sound absorbing cylinders are provided in a plurality of stages with respect to the air flow direction in the duct, and the sound absorbing cylinders of each stage are arranged at right angles to the air flow direction and parallel to each other. The silencer according to claim 1 or 2, wherein 4. The sound absorbing cylinder has a hollow structure having non-breathable reflectors at both ends, and a plurality of sound absorbing cylinders are arranged parallel to the air flow direction in the duct. The silencer according to claim 1 or 2.