JPH06146845A - Noise eliminating device - Google Patents

Abstract

PURPOSE:To obtain a high noise eliminating performance of a device whose weight is reduced and whose resistance in relation to fluid is reduced. CONSTITUTION:In a noise eliminating device 1 provided in such constitution that a plurality of noise absorbing cylinders 2 formed by filling an noise absorbing material in a clearance between each outer cylinder 4 and inner cylinder 6 which are arranged at intervals and being formed in a square cylindrical shape are arranged in line in a casing 10, multiple transmission holes are formed on the outer cylinder 4 and the inner cylinder 6 of each noise absorbing cylinder 2, and a plurality of noise absorbing cylinder 2 is arranged zigzag the casing 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a muffler for silencing noise (sound waves) generated by a blower or the like, and more particularly to a muffler suitable for silencing a large blower or the like.

[0002]

2. Description of the Related Art Conventionally, sound waves generated from a blower,
Various proposals have been made as a muffling device that muffles sound using a sound absorbing tube.

As a conventional example of these, the Japanese Utility Model Publication 48-2
There are silencers described in Japanese Patent No. 9201, Japanese Utility Model Publication No. 49-16564, Japanese Utility Model Publication No. 1-95517, etc., respectively.

The silencer disclosed in Japanese Utility Model Publication No. 48-29201 has a structure in which a plurality of prismatic sound absorbing cylinders are arranged in a casing via corrugated spacing plates.

The muffler disclosed in Japanese Utility Model Publication No. 49-16564 has a structure in which a plurality of rectangular sound absorbing tubes are stacked and arranged in a grid pattern.

The muffler disclosed in Japanese Utility Model Laid-Open No. 1-95517 has a structure in which a plurality of cylindrical sound absorbing cylinders are stacked in a zigzag pattern or a grid pattern.

[0007]

By the way, at present,
BACKGROUND ART High performance, small size, and light weight of various devices are constantly being pursued, and a muffling device used for a blower and the like having a large capacity and a large size is also desired to be lightweight and have high muffling performance.

However, in each of the above-described conventional silencers, since the plurality of sound absorbing cylinders are closely arranged in close proximity to each other, for example, the guide cylinder is arranged in the casing having a square cross section with a side of 10 m. However, there is a problem that the weight of the muffler becomes heavy.

Further, as described in Japanese Utility Model Laid-Open No. 1-95517, in order to stack a plurality of cylindrical sound absorbing cylinders in a zigzag manner, a casing having a special shape adapted to this stacking structure is required, and the number of parts is increased. However, there is a problem in that the weight further increases with the increase of.

Further, in each of the conventional sound deadening devices, since the plurality of sound absorbing cylinders are arranged close to each other and densely arranged, each sound absorbing cylinder is arranged with respect to the total cross-sectional area of the casing in which the plurality of sound absorbing cylinders are arranged. The ratio of the area occupied by the cylinder is large, and for example, in the case of a cylindrical sound absorbing cylinder, the area through which the fluid can pass (open area) is about half of the total cross-sectional area in the casing. Therefore, there has been a problem that the resistance to the fluid becomes large and the pressure loss becomes large.

The present invention has been made in view of these points, and overcomes the above-mentioned problems in the conventional ones.
An object of the present invention is to provide a sound deadening device which can obtain good sound deadening performance, is light in weight, and has low resistance to fluid.

[0012]

In order to achieve the above-mentioned object, a silencer of the present invention according to claim 1 is arranged between the outer cylinder and the inner cylinder, which are arranged with a gap and are each formed in a square cylinder shape. In a sound deadening device in which a plurality of sound absorbing cylinders filled with a sound absorbing material in a gap are aligned in a casing, a plurality of through holes are formed in an outer cylinder and an inner cylinder of each sound absorbing cylinder, and a plurality of the sound absorbing cylinders are formed. The cylinders are arranged in a staggered manner in the casing.

A sound deadening device according to a second aspect of the present invention is characterized in that, in the first aspect, at least a part of the plurality of sound absorbing tubes is formed in a rectangular tubular shape.

[0014]

According to the silencer of the present invention as set forth in claim 1,
Since the sound absorbing cylinders formed in a plurality of quadrangular shapes can be easily arranged in a staggered manner, the number of the sound absorbing cylinders used can be reduced without changing the sound deadening performance.
The weight of the silencer can be reduced and the area through which the fluid can pass can be increased.

As described in claim 2, when at least a part of the plurality of quadrangular sound absorbing cylinders has a rectangular cylindrical shape having long sides and short sides, the above-described operation according to claim 1 is performed. In addition, it is possible to particularly significantly muffle sound waves of a specific frequency corresponding to the dimensions of the long side and the short side, and it is possible to make sound waves having a level of the specific frequency protruding over the entire frequency range of the sound waves. .

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

First, an embodiment of a sound absorbing cylinder used in the sound deadening apparatus according to the present invention will be described with reference to FIGS.

FIGS. 1 to 3 show an embodiment of a sound absorbing cylinder applied to a sound deadening apparatus according to the present invention. FIG. 1 is a partially cutaway side view showing a main part of the sound absorbing cylinder, and FIG. 1 is a cross-sectional view taken along the line AA of FIG. 1, and FIG.

As shown in FIGS. 1 and 2, the sound absorbing cylinder 2 used in the noise canceling device 1 of the present embodiment, which will be described later, has a large number of small-diameter through holes 3, 3 ,. In the rectangular outer cylinder 4 having a length of 4 mm, a large number of small-diameter through holes 5, 5 ... And the appropriate sound absorbing material 7 is filled in this gap, and
By connecting the respective ends of the prismatic outer cylinder 4 and the respective ends of the prismatic inner cylinder 6 with appropriate mouthpieces 8 and 8 which can properly receive sound waves inward, a substantially hollow rectangular cylindrical shape ( Rectangular). The long side wall portion 4a and the short side wall portion 4b of the prismatic outer cylinder 4 are connected to each other by inclined walls 9 having desired angles. This inclined wall 9
Is for safety when stacking the sound absorbing cylinders 2.

The material of the prismatic outer cylinder 4 and the prismatic inner cylinder 4 is preferably an aluminum alloy which is lightweight and excellent in corrosion resistance, but is not limited thereto. Also,
The through holes 3 and 5 may be formed by a perforated plate called a punching board, for example.

The sound absorbing material 7 may be any known material having sound absorbing properties, such as glass wool and rock wool.
Various ones can be selected.

The shape of the mouthpiece 8 may be a mouthpiece 8a having a mountain-shaped cross section having an apex in the axial direction as shown in FIG. 3, and is not particularly limited to the shape shown in FIG.

Next, an embodiment of the silencer according to the present invention will be described.

FIG. 4 is a schematic view showing an embodiment in which the silencer according to the present invention is applied to a ventilation duct.

As shown in FIG. 4, the silencer 1 according to this embodiment.
, A plurality of the sound absorbing cylinders 2, 2, ... In a desired ventilation duct 10 having a rectangular tubular shape in vertical cross section which forms a casing, the inclined walls 9 formed in each rectangular outer cylinder 4 face each other, Two adjacent sound absorbing cylinders 2 and 2 arranged at intervals are provided with two inclined walls 9 and 9 at the lower ends of the other sound absorbing cylinders 2 on the mutually facing upper end inclined walls 9 and 9, respectively. A plurality of sound absorbing cylinders 2 are arranged in a staggered manner so that the seats are seated.

In the present embodiment, the inclined walls 9 formed on the rectangular outer cylinder 4 of the sound absorbing cylinder 2 are opposed to each other, but as shown in FIG. 5, instead of the inclined wall 9, a rectangular shape is formed. A sound absorbing cylinder 2a using a rectangular outer cylinder 4a having stepped recesses 11 formed at four corners is provided, and the stepped recesses 11 are opposed to each other and two adjacent sound absorbing cylinders 2 and 2 are arranged at intervals. Of the sound absorbing cylinders 2a by fitting the two stepped recesses 11, 11 at the lower end of the other sound absorbing cylinder 2a into the stepped recesses 11, 11 at the upper end facing each other. The sound deadening devices 1a may be arranged in a staggered manner. Further, the prismatic outer cylinder 4 may not be provided with the slanted wall 9 or the stepped recessed portion 11 but may have a structure in which an appropriate support member for zigzag arrangement (not shown) is interposed. In particular, the shape shown in FIG. It is not limited.

Further, the sound absorbing panel 10 having an appropriate through hole in a portion of the inner surface of the ventilation duct 10 where the sound absorbing cylinders 2, 2, ... Are not arranged, as indicated by a broken line in FIGS. 4 and 5.
a is attached or an appropriate sound absorbing panel (not shown) is attached to the entire inner surface of the ventilation duct 10, and the sound absorbing cylinders 2, 2, ... Are staggered in the sound absorbing panel to further improve the sound absorbing effect. Can be improved.

Further, the square sound absorbing cylinders 2 of the sound deadening device 1 which are arranged in a zigzag manner may be fixed to each other by an appropriate fixing member (not shown) such as a rivet or band, or welding.

Next, the operation of this embodiment having the above-mentioned structure will be described with reference to FIGS.

As described above, the silencer 1 of this embodiment
Is a rectangular outer cylinder 4 of the sound absorbing cylinder 2 with an inclined wall 9 or a stepped recess 1
Since the plurality of sound absorbing cylinders 2 are formed, the plurality of sound absorbing cylinders 2 can be arranged easily and surely in a staggered manner by joining or engaging the inclined walls 9 or the stepped recesses 11 with each other.

The sound waves of the fluid passing through the axial center portion and the outer peripheral portion of the sound absorbing cylinder 2 of the sound deadening device 1 are provided with a large number of through holes 3, 3, ... A large number of through holes 5, 5, ... Formed in the inner cylinder 6 flow into the gap of the sound absorbing cylinder 2 and are absorbed by the sound absorbing material 7 filled in the gap of the sound absorbing cylinder 2.

Since a plurality of sound absorbing cylinders 2 are arranged in a staggered manner, for example, the ventilation duct 1 having a square cross section with a side of 10 m.
The number of sound absorbing cylinders 2 arranged in 0 can be halved to about 25, which was conventionally required to be about 50.
It is possible to surely reduce the weight of the silencer 1. The reduction in the number of sound absorbing tubes 2 used can surely increase the area (open area) through which the fluid can pass.

Further, since the sound absorbing cylinder 2 is a substantially hollow rectangular cylinder having at least a long side and a short side, the ratio between the long side and the short side of the sound absorbing cylinder 2 is appropriately changed (for example, 1.5). : 1 to
By setting 5.0: 1), it is possible to correspond to the peak frequency of the sound wave to be silenced. That is, when the frequency characteristic of the sound wave to be silenced has a high peak at a specific frequency, by setting the length dimensions of the long side and the short side of the sound absorbing cylinder 2 to correspond to the peak frequency, the peak Can be attenuated particularly greatly, and a sound deadening characteristic can be obtained in which the sound pressure is uniform over all frequencies of the sound wave.

The sound absorbing cylinder 2 may be formed in a hollow quadrangular shape (square shape) to effectively muffle a specific peak frequency.

Next, a comparative experiment example of the silencing performance of the silencing device of this embodiment and the conventional silencing device will be illustrated.

In this comparative experiment, the air volume was 10,000 m ³ / m.
in, wind pressure: 1000 mmAq, rotation speed: 1000 rp
m, generated noise: 115 db (A), fundamental frequency: 133
4500mm x 4x connected to the inlet of the Hz fan
The noise level was measured by arranging the muffler in the 050 mm duct 10b and arranging the stylus of the sound level meter 1 m before the fluid suction surface of the muffler.

As the sound deadening device 1a of the present invention used in this comparative experiment, the rectangular sound absorbing tube 2a shown in FIG.
A conventional silencer 12 for comparison is used, in which three ducts are arranged in a staggered manner in the duct 10b as shown in FIG.
As the material, 56 cylindrical sound absorbing cylinders 13 shown in FIG. 7 were used and stacked in the duct in a grid pattern shown in FIG.

The number of stages of the silencer (first stage, second stage, third stage) was used as a parameter.

9 and 10 show the results of the comparative experiment.

As is clear from the results of the comparative experiment shown in FIG. 9, the sound deadening device 1a of the present invention used in this comparative experiment has a cylindrical sound absorbing tube of the conventional sound deadening device 12 in which each stage of the sound absorbing tube 2a is used. Although it is significantly smaller than the number of used silencers 13, it has a silence characteristic equivalent to that of the conventional silencer 12. The noise suppressor 1a of the present invention has a noise frequency of 63-
It was found that in the range of 250 Hz, noise silencing characteristics are improved as compared with the conventional silencing device 12.

Further, as is clear from the results of the comparative experiment shown in FIG. 10, when the muffler is used in multiple stages,
It has been found that the muffling volume of the noise level A characteristic (human audible frequency) of the muffling apparatus 1a of the present invention used in this comparative experiment is superior to the conventional muffling apparatus 12 as the number of stages increases.

Therefore, the muffling device 1a of the present invention has the same or better muffling performance than the conventional muffling device 12, and can surely be reduced in weight and economical burden.

Further, the silencer 1, 1a of the above-mentioned embodiment
In the case where the sound absorbing cylinders 2 and 2a of each stage are connected in the vertical and horizontal directions in the fluid flow direction, the sound deadening effect can be improved. . Then, the mufflers 1 and 1a may be arranged offset from each other. Further, if necessary, appropriate baffles (not shown) may be provided in the fluid passages inside the sound absorbing cylinders 2 and 2a arranged in a staggered manner and in the fluid passages outside the sound absorbing cylinders 2 and 2a facing each other. Good.

Further, as shown in FIG. 11, an appropriate engaging recess 14 is provided at the center of the long side of the square inner cylinder 6 of the sound absorbing cylinder 2.
By detachably attaching an appropriate sound absorbing panel 16 shown by a broken line in the drawing having an engaging protrusion 15 corresponding to the engaging recess 14 or an appropriate baffle (not shown),
The flow path inside the sound absorbing cylinder 2 can be selectively used as one flow path having a rectangular cross section and two flow paths having a square cross section. When the sound wave of a specific frequency is to be silenced, the above 2
It is effective to use the sound absorbing cylinder 2 having two flow channels each having a square cross section. Further, the sound absorbing panel 16 is made up of an appropriate sound absorbing material 7
A housing having a desired through hole filled with may be used.

The present invention is not limited to the above embodiment, but can be modified as necessary.

[0046]

As described above, according to the silencer of the present invention, it is possible to obtain a lightweight silencer having a low resistance to fluid while maintaining the conventional silencer performance. .

[Brief description of drawings]

FIG. 1 is a partially cut side view showing a main part of an embodiment of a sound absorbing cylinder applied to a sound deadening device according to the present invention.

FIG. 2 is a sectional view taken along the line II of FIG.

FIG. 3 is a sectional view of the vicinity of the base showing another embodiment of the base.

FIG. 4 is a schematic diagram showing an embodiment in which the muffler according to the present invention is applied to a ventilation duct.

FIG. 5 is a schematic view showing another embodiment of the silencer according to the present invention.

FIG. 6 is a vertical cross-sectional view and a front view showing a sound absorbing cylinder of the sound deadening device of the present invention used in a comparative experiment.

FIG. 7 is a detailed view showing a cylindrical sound absorbing tube of a conventional silencer used in a comparative experiment.

FIG. 8 is a diagram illustrating an arrangement state of a conventional silencer used in a comparative experiment.

FIG. 9 is a diagram showing the results of comparative experiments on the silencing characteristics of the silencing device of the present invention and the conventional silencing device.

FIG. 10 is a diagram showing the results of comparative experiments on the silencing characteristics of the silencing device of the present invention and the conventional silencing device according to the number of stages.

FIG. 11 is a schematic view showing another embodiment of the sound absorbing cylinder applied to the sound deadening device according to the present invention.

[Explanation of symbols]

 1, 1a Muffler 2, 2a Sound absorbing cylinder 3 Through hole 4, 4c Square outer cylinder 4a Long side wall 4b Short side wall 5 Through hole 6 Square inner cylinder 7 Sound absorbing material 8, 8a Base 9 Inclined wall 10, 10b duct 11 stepped recess

Claims (2)

[Claims] 1. A sound deadening device in which a plurality of sound absorbing cylinders, which are filled with a sound absorbing material in the space between the outer cylinder and the inner cylinder, which are arranged with a gap and are each formed in a rectangular tube shape, are aligned in a casing. The sound deadening device according to claim 1, wherein a plurality of through holes are formed in the outer cylinder and the inner cylinder of each sound absorbing cylinder, and the plurality of sound absorbing cylinders are arranged in a staggered manner in the casing. 2. The sound deadening device according to claim 1, wherein at least a part of the plurality of sound absorbing cylinders is formed in a rectangular cylinder shape.