JP2002328678A - Sound reducing device for gas flow passage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound reducing device for gas flow passage which is capable of reducing the noises of a broad frequency band with a low pressure drop without upsizing the whole of the device. SOLUTION: A plurality of sound reducing bodies consisting of air permeable ceramics having fine pores are installed in juxtaposition apart prescribed intervals in mid-way of the gas flow passage so as to partition the gas flow passage and the inner walls of the gas flow passage between the sound reducing bodies are provided with acoustic materials so that the sounds can be reduced while gas is allowed to pass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for reducing noise generated from a device having a gas passage for intake and exhaust, such as various fans, various compressors, various combustion devices, and the like.

[0002]

2. Description of the Related Art Conventionally, various fans, various compressors,
Since various types of combustion equipment and the like emit loud noises from the apparatus itself, the noises leak out particularly through the gas passages for intake and exhaust, resulting in noise. In order to reduce this noise, a method has been proposed in which a sound absorbing material is attached to the gas flow path to absorb the sound, or the gas flow path itself is bent so that the sound is irregularly reflected and attenuated in the flow path. . However, in such a method, the sound absorbing material is thickened or the gas flow path is bent in a complicated manner in order to enhance the noise reduction effect. There is a problem that the influence on the device is increased. Also, it was not possible to reduce only the sound in a specific frequency band.

[0003]

SUMMARY OF THE INVENTION The problem to be solved by the present invention is to solve these problems in the prior art, and to provide a gas passage for intake and exhaust of various fans, various compressors, various combustion devices and the like. It is an object of the present invention to provide a noise reduction device for a gas flow path that can reduce noise in a wide frequency band with low pressure loss without increasing the size of the device as a whole.

[0004]

Means for Solving the Problems The constitution of the present invention which has solved the above-mentioned problems is as follows: 1) A sound absorber made of a gas-permeable ceramic having fine pores in the middle of a gas flow path is defined so as to partition the gas flow path. A plurality of sound absorbers are provided side by side at intervals, and a sound absorbing material is provided on the inner wall of the gas flow path between the sound reducers so that the sound can be reduced while passing the gas. 2) Gas flow path The middle part is partitioned by a wall made of a sound absorbing material, and a duct smaller than the cross-sectional area of the gas flow path with a grid-like straightening plate provided inside the wall is provided. A reflector having a substantially U-shaped cross section made of a sound absorbing material having an area larger than the opening is provided, and a predetermined space is provided so that a sound reducer made of a breathable ceramic having fine porosity is partitioned on the back side of the reflector into a gas flow path. Multiple units are installed side by side, from the wall to the sound absorber. Sound absorbing material provided on the inner wall of the body flow path so that sound can be reduced while passing gas. 3) The first sound absorbing chamber surrounded by the sound absorbing material in the middle of the gas flow path. A plurality of reflective gallery that reflects sound to the sound source side in the first sound absorbing chamber are provided at predetermined intervals so that gas passes therethrough, and the opposite side of the reflective gallery from the sound source is partitioned by a wall made of a sound absorbing material. At the same time, a duct smaller than the cross-sectional area of the gas flow path with a grid-shaped rectifying plate provided inside the wall is provided. A plurality of sound reducers made of breathable ceramics having fine porosity are arranged in parallel at a predetermined interval on the back side of the reflector at predetermined intervals so as to partition the gas flow path. Install a sound absorbing material on the inner wall of the gas flow path to the sound absorber, 4) A first sound absorbing chamber surrounded by a sound absorbing material is provided in the middle of the gas flow path, and the sound is provided on the sound source side in the first sound absorbing chamber. A plurality of reflective galleries to be reflected are provided at predetermined intervals so that gas passes therethrough, and the opposite side of the reflective galleries from the sound source is partitioned by a wall made of a sound absorbing material, and a grid-like rectifying plate is provided inside the wall. A duct smaller than the cross-sectional area of the provided gas flow path is provided, and a reflector having a substantially U-shaped cross section made of a sound absorbing material having an area larger than the opening of the duct is provided at a position facing the outlet side of the duct, and a rear side of the reflector. A plurality of sound reducers made of breathable ceramics having fine porosity are arranged in parallel at predetermined intervals so as to partition the gas flow path, and a plurality of sound reducers surrounded by a sound absorbing material on the opposite side to the sound source of the plurality of sound reducers. Two sound absorbing chambers are provided, and sound is generated at the gas inlet and outlet of the second sound absorbing chamber. A plurality of reflection gulls are provided at predetermined intervals so that gas passes therethrough, and a sound absorbing material is provided on an inner wall of a gas flow path from the first sound absorbing chamber to the second sound absorbing chamber to reduce sound while passing the gas. A sound reducing device for a gas flow path that can make sound.

[0005]

According to the structure of the first aspect of the present invention, the sound emitted from the device hits the sound reducer, and is gradually reduced while complicatedly and diffusely reflected in the fine pores of the sound reducer. Further, the gas smoothly passes through the fine pores, so that the pressure loss is small. In the configuration according to the second aspect of the present invention, the sound emitted from the device enters the duct, is guided in one direction by the duct, hits the reflector, and the sound traveling straight while being reduced by the sound absorbing material of the reflector is the sound source. Returning to the side, the sound reflected off the duct is reflected by the sound absorbing material of the gas flow path while being reduced, and hits the sound reducer. Then, the sound is gradually reduced while complicatedly reflecting irregularly in the minute pores of the sound reducer. In the configuration according to claim 3 of the present invention, the sound emitted from the device is reflected in various directions by the reflection gallery, and only the sound that passes through the reflection gallery while being reduced by the sound absorbing material in the gas flow path is transmitted to the duct. enter in. The sound that enters the duct is guided in one direction by the duct and hits the reflector.The sound that goes straight while being reduced by the sound absorbing material of the reflector returns to the sound source side, and the sound that reflects off the duct is the gas flow path. The sound is reflected by the sound absorbing material while being reflected, and hits the sound absorber. Then, the sound is gradually reduced while complicatedly reflecting irregularly in the minute pores of the sound reduction body. In the configuration according to claim 4 of the present invention, the sound emitted from the device is reflected in various directions by the reflection gallery of the first sound absorbing chamber, and passes through the reflection gallery while being reduced by the sound absorbing material of the gas flow path. Only sound enters the duct. The sound that enters the duct is guided in one direction by the duct and hits the reflector.The sound that goes straight while being reduced by the sound absorbing material of the reflector returns to the sound source side, and the sound that reflects off the duct is the gas flow path. The sound is reflected by the sound absorbing material while being reflected, and hits the sound absorber. The sound that hits the sound absorber is gradually reduced while complicatedly reflecting irregularly in the minute pores, and the sound that escapes from the sound reducer is reflected in various directions by the reflection gallery of the second sound absorbing room, and is reduced. You.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION As a sound reducing body, 70 μm to 1 m
A ceramics material having an air permeability of 0.9 or more, such as alumina ceramics, fly ash ceramics, fly ash ceramics, and the like, which uniformly have fine open-cell porosity having a size of m is used. 10m in thickness
The size is generally in the range of m to 30 mm, but can be arbitrarily changed according to the intake / exhaust volume and capacity of the equipment to be attached. As the sound-absorbing material, a material in which inorganic fibrous materials such as glass wool and rock wool are mixed is generally used, but if it exhibits other sound-absorbing properties, the temperature of the air intake and exhaust of the equipment etc. should be considered. It is selected after doing. A thickness in the range of 25 mm to 50 mm can provide a sufficient noise reduction effect, but can be arbitrarily changed according to the required noise reduction effect. Ducts with a grid-shaped rectifying plate improve the straightness of sound and gas. As the rectifying plate, a steel plate, an aluminum plate, or those provided with a sound absorbing material on their inner wall surfaces are used. Any shape including a honeycomb having a square cross section or other polygonal shapes can be adopted. The reflector absorbs the sound coming from the duct and reflects it while reducing the sound.It is made of a sound-absorbing material mixed with an inorganic fibrous material such as glass wool or rock wool, and has a substantially U-shaped cross section. It is. The back is reinforced with a steel plate or the like to maintain its shape. The reflection gull is formed by bending a steel plate. One side bent at an obtuse angle is formed in a substantially arc shape, and diffusely reflects sound in various directions and smoothes a gas flow path. Four to eight reflection galleries are arranged at predetermined intervals so that sound and gas do not travel straight. The equipment for sucking and discharging gas as referred to in the present invention includes various fans used for ventilation and the like, various compressors for compressing and sending out air, and various combustion equipment such as boilers and turbines. The noise reduction device of the present invention is attached to the flow path through which the gas passes. The sound reducers are generally mounted on both the intake and the exhaust one by one, but a plurality of sound reducers may be mounted in series on one of the flow paths.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment shown in FIGS. 1 to 6, a noise reduction device is attached to each of an intake port and an exhaust port of a combustion apparatus so that noise of the combustion apparatus which passes through a gas passage for intake and exhaust can be reduced. This is an example. FIG. 1 is an explanatory diagram of a combustion device according to an embodiment. FIG. 2 is a partially cutaway view of the sound reduction device of the embodiment. FIG. 3 is a cross-sectional view of the first reflection gallery part of the sound reduction device of the embodiment. Drawing 4 is a sectional view of the duct part of the sound reduction device of an example. FIG. 5 is a cross-sectional view of a sound-reducing body of the sound-reducing device of the embodiment. FIG. 6 is a cross-sectional view of the second reflection gallery portion of the sound reduction device according to the embodiment.

In FIG. 1, reference numeral 1 denotes a first reflection gallery portion, as shown in FIG. 3, having an opening 1c formed on one side of an outer frame 1a made of a steel plate and the other raised up to form an opening 1d. Four openings 1e each having a substantially L-shaped cross section and having one side formed in an arc shape are provided in the opening 1d at intervals of 5 mm so that the gas can pass through the opening 1d with the arc directed inward.
A sound absorbing material 1b made of glass wool having a thickness of 25 mm is attached to the inside of the outer frame 1a. 2 is a duct part,
As shown in FIG. 4, a duct 2c made of steel and having a straightening plate having a lattice cross section is attached to an opening communicating with the first reflective gallery portion 1 of an outer frame 2a made of steel plate, and a steel plate is provided on the opposite side of the duct 2c from the sound source. The reflector 2d is provided with a sound absorbing material 2b made of glass wool having a substantially U-shaped cross section and having a thickness of 25 mm inside. Inside the outer frame 2a, a thickness of 25 m is used similarly to the reflector 2d.
m sound absorbing material 2b made of glass wool. Numeral 3 denotes a sound-reducing body part, as shown in FIG. 5, to which a sound absorbing material 3c made of glass wool and having a thickness of 25 mm is mounted inside an outer frame 3a made of a steel plate. Reference numeral 3b denotes sound reducers made of ceramics having high air permeability, which are vertically mounted at intervals of 100 mm. Reference numeral 4 denotes a second reflective gallery portion, as shown in FIG. 6, which has an opening 4b formed on the outer side of the outer frame 4a made of a steel plate on the side opposite to the sound source, and has a substantially L-shaped cross section and one side having an arc shape. Four of the formed gulls 4c are provided at intervals of 30 mm so that the gas can pass through the opening 4b with the arc directed inward. A sound absorbing material 4d made of glass wool having a thickness of 25 mm is attached inside the outer frame 4a. 5
Is a filter, N is a combustion device, and S1 and S2 are sound reduction devices. The solid line indicates the gas flow and the dotted line indicates the sound reflection. .

In this embodiment, the intake side of the combustion equipment N (FIG. 1)
The upper sound reduction device S1 will be described. The exhaust-side noise reduction device S2 has the same structure as that of the intake side. First, as shown in FIG. 3, the operating sound of the combustion device N, which is a sound source, is emitted on the right hand side of the first reflective louver unit 1, and the sound goes straight into the outer frame 1a through the opening 1c.
The sound that travels straight inside is reflected by the gusset 1e as shown by the arrow, and is absorbed by the inner sound absorbing material 1b and reduced. Gullari 1
The sound reflected from the vertical portion of e returns to the sound source side, and the sound reflected from the arc portion is irregularly reflected in various directions depending on the angle, and is gradually reduced by the sound absorbing material 1b. Then, a part of the sound enters the duct portion 2 through the gap between the louvers 1e. The sound is reduced by about 4 dB in the first reflection gallery 1.

Next, as shown in FIG. 4, the sound that has entered the duct portion 2 is guided in one direction by the duct 2c, hits the reflector 2d, is absorbed by the sound absorbing material 2b, and the reflected sound is generated by the sound source on the duct 2c side. Returning to the side, the sound reflected off the duct 2c is absorbed by the sound absorbing material 2b of the outer frame 2a. The sound of the specific frequency can be reduced by adjusting the dimension of L1. Then, a part of the sound escapes to the back side of the reflector 2 d and enters the sound-reducing body 3. The duct section 2 reduces the sound by about 8 dB.

Next, as shown in FIG. 5, the sound that has entered the sound reducing member 3 is absorbed by the sound reducing member 3b and is reduced. The sound reducer 3b is a porous material that is heavy and has a very high air permeability, and exhibits excellent sound reducing ability as compared with other sound reducing mechanisms. In addition, since the main mechanism of sound reduction is heavy, high transmission loss can be expected, and since the reflection phases of both the sound reducers 3b can be adjusted, sound reduction in a specific frequency band is also possible. Other systems can effectively attenuate low-frequency sounds that are difficult to reduce, and the pressure loss of the intake and exhaust air is low, because it is made of a porous material and ceramics with high air permeability. Approximately 20 dB with only this sound reduction body part 3
Therefore, depending on the application, sufficient sound reduction ability can be provided by itself without being combined with another method. The sound of the specific frequency can be reduced by adjusting the dimension of L2. Then, a part of the sound passes through the sound reducer 3 b and enters the second reflection gallery part 4.

As shown in FIG. 6, the sound that has entered the second reflection gallery 4 is reflected by the gallery 4c as indicated by the arrow.
The sound reflected from the vertical portion of the louver 4c returns to the sound source side and passes through the noise reducing body 3b, and the sound reflected from the arc portion is irregularly reflected in various directions depending on the angle, and is gradually reduced by the sound absorbing material 4d. Go. The sound of a specific frequency can be reduced by adjusting the dimension of L3. Then, a part of the sound goes out of the sound reduction device S through the gap between the louvers 4c. The sound is reduced by about 4 dB in the second reflection gallery part 4. Therefore, the sound is reduced by about 36 dB as a whole through four stages.

As described above, in this embodiment, since the sound reduction devices S1 and S2 are attached to both the intake and exhaust of the combustion equipment N, the noise in a wide frequency band can be reduced with low pressure loss without increasing the size as a whole. Can be.

[0015]

As described above, according to the present invention, noise in a wide frequency band can be reduced with low pressure loss without increasing the size as a whole.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a combustion device according to an embodiment.

FIG. 2 is a partially cutaway view of the sound reduction device of the embodiment.

FIG. 3 is a cross-sectional view of a first reflection gallery portion of the sound reduction device according to the embodiment.

FIG. 4 is a sectional view of a duct portion of the sound reduction device of the embodiment.

FIG. 5 is a cross-sectional view of a sound-reducing body of the sound-reducing device of the embodiment.

FIG. 6 is a cross-sectional view of a second reflection gallery in the sound reduction device of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st reflection gallery part 1a Outer frame 1b Sound absorbing material 1c, 1d Opening 1e Gullary 2 Duct part 2a Outer frame 2b Sound absorbing material 2c Duct 2d Reflector 3 Sound reducer part 3a Outer frame 3b Sound reducer 3c Sound absorbing material 4 Second Sound wave reflection gallery 4a Outer frame 4b Opening 4c gallery 4d Sound absorbing material 5 Filter N Combustion equipment S1 Sound reducer S2 Sound reducer

Continuing from the front page (71) Applicant 390032676 Isobe Iron Works, Ltd. 1-115, Nagafu Ogimachi, Shimonoseki City, Yamaguchi Prefecture (72) Inventor Hiroshi Suzuki 2-182 Watanabe-dori, Chuo-ku, Fukuoka City, Fukuoka Prefecture Inside Kyushu Electric Power Company (72) Inventor Shigeharu Ashida 1-17-8 Shirogane, Chuo-ku, Fukuoka City, Fukuoka Prefecture Inside Nippon Environmental Energy Corporation (72) Inventor Tadaomi Toeda 1-6-9, Yakuin, Chuo-ku, Fukuoka City, Fukuoka Prefecture Towa Kogyo Co., Ltd. In-house (72) Inventor Susumu Akie 1-15 Nagao Ogimachi, Shimonoseki City, Yamaguchi Prefecture Isobe Iron Works Co., Ltd.F-term (reference)

Claims (4)

[Claims] 1. A plurality of sound reducers made of air-permeable ceramics having fine porosity in the middle of a gas flow path are arranged in parallel at predetermined intervals so as to partition the gas flow path, and a gas flow path between the sound reducers is provided. A sound reducing device for a gas flow path, wherein a sound absorbing material is provided on an inner wall of the gas passage so that sound can be reduced while passing gas. 2. A duct smaller than the cross-sectional area of a gas flow path having a gas flow path partitioned inside a gas flow path with a wall made of a sound-absorbing material and having a grid-like straightening plate provided inside the wall. A reflector having a substantially U-shaped cross section made of a sound absorbing material having an area larger than the opening of the duct is provided at a position opposite to the side of the duct, and a sound reducer made of breathable ceramics having fine pores is provided on the back side of the reflector. A plurality of gas passages that are arranged side by side at predetermined intervals so as to partition the path, and a sound absorbing material is provided on the inner wall of the gas passage from the wall to the sound reducer so that the sound can be reduced while passing the gas. Sound reduction device. 3. A first gas pump surrounded by a sound absorbing material in the middle of a gas flow path.
A plurality of sound absorbing chambers are provided at predetermined intervals so that a gas passes through a reflection gallery that reflects sound to the sound source side in the first sound absorption chamber, and the opposite side of the reflection gallery from the sound source is a wall made of a sound absorbing material. With a partition, a duct smaller than the cross-sectional area of the gas flow path with a grid-like straightening plate provided inside the same wall is provided,
A substantially U-shaped reflector made of a sound absorbing material having an area larger than the opening of the duct is provided at a position facing the outlet side of the duct, and a sound absorber made of breathable ceramics having fine pores on the back side of the reflector. Are arranged side by side at predetermined intervals so as to partition the gas flow path, and a sound absorbing material is provided on the inner wall of the gas flow path from the first sound absorbing chamber to the sound reducer so that the sound can be reduced while passing the gas. Gas passage noise reduction device. 4. A first gas chamber surrounded by a sound absorbing material in the middle of a gas flow path.
A plurality of sound absorbing chambers are provided at predetermined intervals so that a gas passes through a reflection gallery that reflects sound to the sound source side in the first sound absorption chamber, and the opposite side of the reflection gallery from the sound source is a wall made of a sound absorbing material. With a partition, a duct smaller than the cross-sectional area of the gas flow path with a grid-like straightening plate provided inside the same wall is provided,
A substantially U-shaped reflector made of a sound absorbing material having an area larger than the opening of the duct is provided at a position facing the outlet side of the duct, and a sound absorber made of breathable ceramics having fine pores on the back side of the reflector. Are arranged side by side at predetermined intervals so as to partition the gas flow path, and a second sound absorbing chamber surrounded by a sound absorbing material is provided on the side opposite to the sound source of the plurality of sound reducing bodies. A plurality of reflection gallery that reflects sound to the sound source side at the entrance and exit are provided at predetermined intervals so that gas passes therethrough, and a sound absorbing material is provided on an inner wall of a gas flow path from the first sound absorbing chamber to the second sound absorbing chamber, and the gas is removed. A gas flow path noise reduction device that can reduce sound while passing through.