JP3207896B2 - Silencer - Google Patents
SilencerInfo
- Publication number
- JP3207896B2 JP3207896B2 JP30411291A JP30411291A JP3207896B2 JP 3207896 B2 JP3207896 B2 JP 3207896B2 JP 30411291 A JP30411291 A JP 30411291A JP 30411291 A JP30411291 A JP 30411291A JP 3207896 B2 JP3207896 B2 JP 3207896B2
- Authority
- JP
- Japan
- Prior art keywords
- noise
- sound
- flow direction
- sound absorbing
- gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Description
【0001】[0001]
【産業上の利用分野】本発明は、気体が流れるダクト内
に設置され特定周波数(送風機の場合は基本周波数と倍
音)で大きくなる騒音を効果的に減少させる消音器に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a muffler installed in a duct through which gas flows to effectively reduce noise that increases at a specific frequency (for a blower, the fundamental frequency and harmonics).
【0002】[0002]
【従来の技術】従来、気体が流れるダクト内に設置され
る消音器としては、例えば図2に示すような吸音面が気
体の流れに平行になるように設けられた吸音スプリッタ
や、吸音セルを内蔵した構造のものが良く知られてい
る。しかしこのような構造の吸音型消音器では、吸音材
9の飛散防止のため吸音材9を覆っているカバー11に
設ける多孔の開口率を余り大きく採ることができない。2. Description of the Related Art Conventionally, as a muffler installed in a duct through which gas flows, for example, a sound absorbing splitter or a sound absorbing cell provided with a sound absorbing surface parallel to the gas flow as shown in FIG. Those with a built-in structure are well known. However, in the sound-absorbing silencer having such a structure, the aperture ratio of the perforations provided in the cover 11 that covers the sound-absorbing material 9 cannot be made too large in order to prevent the sound-absorbing material 9 from scattering.
【0003】このため、気体中の固形分により開口部が
目詰まりを起こし、消音性能の低下を生じ易い。特に、
石炭燃焼ボイラ等の煙道に於いて排ガス誘引通風機の前
後に設けられる消音器では、排ガス中に含まれる多量の
灰粉等による吸音面の多孔の目詰まりが著しく、消音器
の性能が急激に低下することがあった。又、これを防止
するために消音器を頻繁に洗浄しなければならなかっ
た。[0003] Therefore, the solid portion in the gas causes clogging of the opening, which tends to cause a reduction in the noise reduction performance. In particular,
In silencers installed in the flue of coal-fired boilers, etc., before and after the exhaust gas induction ventilator, the pores on the sound-absorbing surface due to the large amount of ash powder contained in the exhaust gas are remarkably clogged, and the performance of the silencer sharply increases. In some cases. Also, the silencer must be cleaned frequently to prevent this.
【0004】一方、騒音源には、例えば送風機のよう
に、羽根の枚数と回転数との関係で特定の周波数(基本
周波数と倍音)でピークとなる騒音を発生させるものが
多い。このようにピーク周波数の特定されている騒音に
対しても、吸音型の構造のみを有する消音器を用いるの
では、効果的な消音効果を得ることが困難である。On the other hand, many noise sources, such as blowers, generate noise that peaks at a specific frequency (basic frequency and harmonic) in relation to the number of blades and the number of rotations. It is difficult to obtain an effective noise reduction effect by using a muffler having only a sound absorbing type structure even for noise having a specified peak frequency.
【0005】[0005]
【発明が解決しようとする課題】本発明は従来技術に於
ける上記問題を解決し、請求項1の発明は、経時におけ
る性能低下が少ないと共に、ピーク周波数の特定されて
いる騒音を効率よく減衰させることができる消音器を提
供することを課題とし、請求項2の発明は、上記に加え
て、騒音の大きくなるピーク周波数(倍音)が複数ある
場合にも、消音効果の大きい消音器を提供することを課
題とする。SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art. According to the first aspect of the present invention, there is little deterioration in performance over time and efficient attenuation of noise whose peak frequency is specified. It is an object of the present invention to provide a muffler that has a large muffling effect even when there are a plurality of peak frequencies (overtones) at which noise increases, in addition to the above. The task is to
【0006】[0006]
【課題を解決しようとする手段】本発明は上記課題を解
決するために、請求項1の発明は、気体の流れるダクト
内に設置され特定周波数で大きくなる騒音を効果的に減
少させる消音器に於いて、前記気体の流れ方向に直角又
は傾斜して間隔を置いて前記流れ方向に配設された複数
の消音部材と、該複数の消音部材の一端側を閉鎖する閉
鎖部材と、を備えた消音部を有し、前記消音部材は、内
部に充填された吸音材と気体の流れ方向の下流側面に設
けられた多数の小孔とを備え、前記消音部材と前記閉鎖
部材とで形成される空間部分の前記流れ方向に直角方向
の深さを、前記特定周波数で大きくなる騒音の波長の1
/3乃至1/6としたことを特徴とし、請求項2の発明
は、請求項1の発明の特徴に加えて、前記特定周波数が
複数あり、前記消音部は、前記空間部分の前記流れ方向
に直角方向の深さが前記複数の周波数で大きくなる騒音
のそれぞれの波長の1/3乃至1/6であるそれぞれ複
数の消音部から成ることを特徴とする。SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a muffler which is installed in a duct through which gas flows and which effectively reduces noise that increases at a specific frequency. A plurality of silencing members arranged at right angles or inclined to the flow direction of the gas at intervals in the flow direction, and a closing member for closing one end of the plurality of muffling members. A silencing member, wherein the silencing member includes a sound absorbing material filled therein and a plurality of small holes provided on a downstream side surface in a gas flow direction, and is formed by the silencing member and the closing member. The depth of the space portion in the direction perpendicular to the flow direction is set to one of the wavelengths of the noise that increases at the specific frequency.
According to a second aspect of the present invention, in addition to the features of the first aspect, there are a plurality of the specific frequencies, and the muffling section is provided in the flow direction of the space portion. And a plurality of muffling portions each having a depth in a direction perpendicular to the wavelength range of 1/3 to 1/6 of each wavelength of the noise increasing at the plurality of frequencies.
【0007】[0007]
【作 用】請求項1の発明によれば、複数の消音部材を
気体の流れ方向に直角又は傾斜して間隔を置いて流れ方
向に配設し、その一端側を閉鎖部材により閉鎖して構成
した消音部を設けるので、消音部には消音部材と閉鎖部
材とにより空間部分が形成され、この空間部分がダクト
内でサイドブランチ部を形成する。そして、空間部分の
流れ方向に直角方向の深さを特定周波数でピークとなる
騒音の波長の1/3乃至1/6程度にするので、サイド
ブランチ部は共鳴空洞としての作用をなし、騒音エネル
ギーの短絡によりこの部分で消音効果が生ずる。更に、
消音部材の内部に吸音材を充填し、気体の流れ方向の反
対側面に多数の小孔を設けるので、この部分では吸音材
の吸音による消音効果が生ずる。そしてこの場合、小孔
が気体の流れ方向に対して後流側に開口し、且つ空間部
分に本流の流速によるエゼクタ作用が生ずるので、空間
部分に気体中の固形分が堆積しにくく小孔部を閉塞させ
ることがないと共に、小孔部に気体の流れが直接当たら
ないため吸音材を飛散させることもない。又、吸音材の
飛散がないことにより、小孔部の開口率を大きくするこ
とが可能となり、吸音効果の向上と共に一層小孔部の閉
塞防止が図られる。According to the first aspect of the present invention, a plurality of muffling members are arranged in the flow direction at a right angle or at an angle to the flow direction of the gas at intervals, and one end thereof is closed by a closing member. Since the muffler is provided, a space is formed in the muffler by the muffling member and the closing member, and the space forms a side branch in the duct. Since the depth in the direction perpendicular to the flow direction of the space portion is set to about 1/3 to 1/6 of the wavelength of the noise peaking at a specific frequency, the side branch portion functions as a resonance cavity, and the noise energy is reduced. The short-circuit causes a silencing effect at this portion. Furthermore,
Since the sound absorbing member is filled inside the sound absorbing member and a number of small holes are provided on the side opposite to the gas flow direction, a sound absorbing effect due to sound absorption of the sound absorbing material occurs in this portion. In this case, the small holes are opened on the downstream side with respect to the gas flow direction, and the ejector action due to the flow velocity of the main flow occurs in the space, so that solids in the gas are less likely to be deposited in the space and the small holes are formed. Is not blocked, and since the gas flow does not directly hit the small holes, the sound absorbing material is not scattered. Further, since there is no scattering of the sound absorbing material, it is possible to increase the aperture ratio of the small holes, thereby improving the sound absorbing effect and further preventing the small holes from being blocked.
【0008】請求項2の発明によれば、特定周波数が複
数ある場合に、消音器をそれぞれの周波数に対応させた
複数の消音部により構成するので、請求項1の発明の作
用に加えて、複数周波数でピークとなる騒音を効果的に
消音することができる。According to the second aspect of the present invention, when there are a plurality of specific frequencies, the silencer is constituted by a plurality of silencers corresponding to the respective frequencies. Noise peaking at a plurality of frequencies can be effectively silenced.
【0009】[0009]
【実 施 例】図1は実施例の消音器の概略構成を示
す。消音器は、ダクト1の一部分として設けられ、複数
の消音部として、送風機の基本周波数の騒音減衰部A0
ゾーン2と2倍音の騒音減衰部A1 ゾーン3とにより構
成されている。そしてそれぞれの消音部は、気体として
の例えば石炭燃焼ボイラからの排ガスの流れ方向から少
し傾斜して間隔を置いて流れ方向に配設された複数の消
音部材である吸音スプリッタ4又は5と、これらの吸音
スプリッタ4、5の一端側を閉鎖するように配設された
閉鎖部材としてのケーシング6又は7とを備え、これら
が一体として結合されフランジ8を介してダクト1に取
付けられている。ケーシング6又は7と吸音スプリッタ
4又は5とにより形成される空間部分は、それぞれ図示
の如くW0 又はW1 の奥行き(深さ)及びH0 又はH1
の間隔を有する。FIG. 1 shows a schematic configuration of a muffler according to an embodiment. Silencer is provided as part of the duct 1, as a plurality of muffling section, noise attenuation portion A 0 of the fundamental frequency of the blower
It is constituted by the zone 2 and the second harmonic overtone sound-damping unit A 1 zone 3. Each of the muffling units is a plurality of muffling splitters 4 or 5 that are a plurality of muffling members arranged in the flow direction at a slight inclination from the flow direction of the exhaust gas from the coal-fired boiler as a gas. And a casing 6 or 7 as a closing member disposed so as to close one end of the sound absorbing splitters 4 and 5. These are integrally connected and attached to the duct 1 via a flange 8. The space formed by the casing 6 or 7 and the sound absorbing splitter 4 or 5 has a depth (depth) of W 0 or W 1 and H 0 or H 1 , respectively, as shown in the figure.
Having an interval of
【0010】更に、それぞれの吸音スプリッタ4又は5
には、その内部に例えばロックウールのような吸音材9
が充填されていて、その排ガスの流れ方向下流側の面に
は多数の小孔10が設けられいる。又、それぞれの吸音
スプリッタ4、5は、その上流側をソリッド板とし、下
流側はエクスパンドメタル等の開口率の高い材料で形成
されている。Furthermore, each of the sound absorbing splitters 4 or 5
Has a sound absorbing material 9 such as rock wool inside.
And a large number of small holes 10 are provided on the surface on the downstream side in the flow direction of the exhaust gas. Each of the sound absorbing splitters 4 and 5 has a solid plate on the upstream side and a material with a high aperture ratio such as expanded metal on the downstream side.
【0011】さて、石炭燃焼ボイラの排ガス系には、排
ガス誘引通風機が設けられる場合が多い。このような通
風機は、通常複数の羽根を持ち、その羽根の回転によ
り、羽根の枚数に対応した基本周波数及びその整数倍の
周波数で最大又は極大となるピーク騒音を発生する。こ
こで騒音スペクトル基本周波数をf0 (Hz )、羽根の
枚数をZ、羽根車の回転速度をN(rpm)とすると、 f0 =NZ/60 であり、消音器ではこのf0 及び少なくとも2f0 の周
波数でピークとなる騒音を効率良く減衰させる必要があ
る。このような周波数の騒音の波長は、基本周波数及び
2倍音に対応するものをそれぞれλ0 、λ1 とすると、
音速をcとすれば、 λ0 =c/f0 、 λ1 =c/2f0 となる。The exhaust gas system of a coal-fired boiler is often provided with an exhaust gas induction ventilator. Such a ventilator usually has a plurality of blades, and the rotation of the blades generates peak noise that is maximum or maximum at a fundamental frequency corresponding to the number of blades and a frequency that is an integral multiple of the fundamental frequency. Here the noise spectral fundamental frequency f 0 (H z), when the number of blades Z, the rotational speed of the impeller and N (rpm), an f 0 = NZ / 60, the f 0 and at least a muffler 2f it is necessary to efficiently attenuate the noise reaches a peak at a frequency of 0. Assuming that the wavelengths of the noise having such a frequency are λ 0 and λ 1 corresponding to the fundamental frequency and the second harmonic, respectively,
Assuming that the sound speed is c, λ 0 = c / f 0 and λ 1 = c / 2f 0 .
【0012】一方、奥行きlp のサイドブランチの共鳴
周波数fp は、理論上、 fp =c/4lp として表される。従って、サイドブランチ部で共鳴によ
り騒音エネルギーを短絡させて消音するためには、奥行
きlp を、 lp =c/4fp =λ/4 にすればよいことになる。Meanwhile, the resonance frequency f p of the side branch of the depth l p is theoretically expressed as f p = c / 4l p. Therefore, in order to mute by short noise energy by resonance by the side branch portion, the depth l p, it is sufficient to l p = c / 4f p = λ / 4.
【0013】そこで本発明では、吸音スプリッタ4、5
で共鳴作用により実質的に消音効果が得られる範囲とし
て、lp に相当する図1に示すW0 又はW1 をそれぞ
れ、 W0 =λ0 /3〜λ0 /6 W1 =λ1 /3〜λ1 /6 になるようにしている。このようにW0 及びW1 に幅を
もたせたのは、騒音の周波数に幅があること等を考慮し
て、W0 、W1 をこの程度の範囲にすれば、共鳴を利用
した消音効果を得ることができるからである。この点
は、発明者等の行った実験によっても確認されている。Therefore, in the present invention, the sound absorbing splitters 4, 5
In the range of substantially silencing effect is obtained by the resonance effect, respectively W 0 or W 1 shown in FIG. 1, which corresponds to l p, W 0 = λ 0 / 3~λ 0/6 W 1 = λ 1 / 3~λ is set to be in the 1/6. The reason why the remembering width W 0 and W 1, taking into account such that there is a range of frequencies of the noise, W 0, if the W 1 in the range of the degree silencing effect utilizing resonance Is obtained. This point has also been confirmed by experiments performed by the inventors.
【0014】次に、吸音スプリッタ4、5の間隔H0 、
H1 は、構造的に適当な寸法になるように、それぞれ略
W0 、W1と同じ長さの等ピッチ間隔になっている。そ
して吸音スプリッタ4、5の枚数は、騒音の大きさ、目
的とする消音後の騒音量、許容空気抵抗等を考慮して定
められる。又、吸音スプリッタ4、5を少し傾斜させて
いるのは、消音効果を余り低下させない範囲で排ガスの
通過抵抗の減少を図るためであるが、これらを排ガスの
流れに対して直角に配置してもよいことは無論である。Next, the interval H 0 between the sound-absorbing splitters 4 and 5,
H 1 is at equal pitch intervals of substantially the same length as W 0 and W 1 , respectively, so as to have a structurally appropriate size. The number of the sound-absorbing splitters 4 and 5 is determined in consideration of the noise level, the target noise amount after silencing, the allowable air resistance, and the like. The reason why the sound absorbing splitters 4 and 5 are slightly inclined is to reduce the passage resistance of the exhaust gas within a range that does not significantly reduce the noise reduction effect, and these are arranged at right angles to the flow of the exhaust gas. The good thing is, of course.
【0015】なお、以上の実施例は、騒音スペクトルの
基本周波数と2倍音との騒音のみを対象としているが、
更に消音器の減音性能を向上させるためには、3倍音及
び4倍音の周波数を対象とした騒音減衰部を追加する
か、又は、このような騒音減衰部を持つ消音器を図1に
示す消音器の下流側に追加して設けることができる。
又、本実施例では石炭燃焼ボイラの排ガス系を例に挙げ
ているが、本発明はこれに限定されることなく、ゴミ焼
却炉等の排ガス系、空気輸送装置、トンネル・トンネル
工事現場等の排気系においても実施し得ることは言うま
でもない。In the above embodiment, only the noise of the fundamental frequency and the second harmonic of the noise spectrum is targeted.
In order to further improve the noise reduction performance of the muffler, a noise attenuator for the third and fourth harmonics is added, or a muffler having such a noise attenuator is shown in FIG. It can be additionally provided downstream of the silencer.
Further, in this embodiment, an exhaust gas system of a coal-fired boiler is taken as an example, but the present invention is not limited to this, and an exhaust gas system such as a garbage incinerator, a pneumatic transportation device, a tunnel / tunnel construction site, etc. Needless to say, the present invention can be applied to an exhaust system.
【0016】[0016]
【発明の効果】以上の如く本発明によれば、請求項1の
発明においては、消音部材において、共鳴による騒音の
減衰と吸音材による騒音の吸音とが同時に行われるの
で、大きな消音効果を得ることができる。又、吸音材を
覆う多数の小孔部の開口率を大きくして気体中の固形分
による多孔の閉塞を防止することができると共に、この
ようにした場合にも吸音材の飛散を防止することができ
る。As described above, according to the present invention, according to the first aspect of the present invention, since the sound attenuating member simultaneously attenuates noise due to resonance and absorbs noise due to the sound absorbing material, a large noise suppressing effect is obtained. be able to. In addition, by increasing the opening ratio of a large number of small holes covering the sound absorbing material, it is possible to prevent the pores from being blocked by solids in the gas, and to prevent the sound absorbing material from scattering even in such a case. Can be.
【0017】請求項2の発明においては、特定周波数が
複数ある場合に、消音器をそれぞれの周波数に対応させ
た複数の消音部により構成するので、上記効果に加え
て、複数周波数でピークとなる騒音を効果的に消音する
ことができる。According to the second aspect of the present invention, when there are a plurality of specific frequencies, the silencer is constituted by a plurality of silencers corresponding to the respective frequencies. Noise can be effectively silenced.
【図1】実施例の消音器の説明図である。FIG. 1 is an explanatory diagram of a muffler according to an embodiment.
【図2】従来の消音器の一例を示す説明図である。FIG. 2 is an explanatory diagram showing an example of a conventional silencer.
1 ダクト 2 騒音減衰部A0 ゾーン(吸音部) 3 騒音減衰部A1 ゾーン(吸音部) 4 吸音スプリッタ(消音部材) 5 吸音スプリッタ(消音部材) 6 ケーシング(閉鎖部材) 7 ケーシング(閉鎖部材) 9 吸音材 10 小孔DESCRIPTION OF SYMBOLS 1 Duct 2 Noise attenuation part A 0 zone (sound absorption part) 3 Noise attenuation part A 1 zone (sound absorption part) 4 Sound absorption splitter (sound absorbing member) 5 Sound absorption splitter (sound absorbing member) 6 Casing (closing member) 7 Casing (closing member) 9 sound absorbing material 10 small hole
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7,DB名) F16L 55/02 - 55/035 F23J 11/00 F01N 1/00 - 1/24 G10K 11/16 ──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. 7 , DB name) F16L 55/02-55/035 F23J 11/00 F01N 1/00-1/24 G10K 11/16
Claims (2)
波数で大きくなる騒音を効果的に減少させる消音器に於
いて、 前記気体の流れ方向に直角又は傾斜して間隔を置いて前
記流れ方向に配設された複数の消音部材と、該複数の消
音部材の一端側を閉鎖する閉鎖部材と、を備えた消音部
を有し、前記消音部材は、内部に充填された吸音材と気
体の流れ方向の下流側面に設けられた多数の小孔とを備
え、前記消音部材と前記閉鎖部材とで形成される空間部
分の前記流れ方向に直角方向深さを、前記特定周波数で
大きくなる騒音の波長の1/3乃至1/6としたことを
特徴とする消音器。1. A silencer installed in a duct through which a gas flows to effectively reduce noise that increases at a specific frequency, wherein the silencer is perpendicular to or inclined to the flow direction of the gas and is spaced apart in the flow direction. A sound-absorbing section including a plurality of arranged sound-absorbing members and a closing member for closing one end of the plurality of sound-absorbing members, wherein the sound absorbing member has a sound-absorbing material and a gas flow filled therein. A number of small holes provided on the downstream side in the direction, the depth of the space portion formed by the silencing member and the closing member in the direction perpendicular to the flow direction, the wavelength of the noise that increases at the specific frequency Muffler characterized in that it is 1/3 to 1/6.
は、前記空間部分の前記流れ方向に直角方向深さが前記
複数の周波数で大きくなる騒音のそれぞれの波長の1/
3乃至1/6であるそれぞれ複数の消音部から成ること
を特徴とする請求項1に記載の消音器。2. The method according to claim 1, wherein the specific frequency includes a plurality of specific frequencies, and the muffling unit is configured to increase a depth of the space portion in a direction perpendicular to the flow direction by 1/1 of each wavelength of the noise that increases at the plurality of frequencies.
The muffler according to claim 1, comprising a plurality of mufflers each having a size of 3 to 1/6.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP30411291A JP3207896B2 (en) | 1991-10-22 | 1991-10-22 | Silencer |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP30411291A JP3207896B2 (en) | 1991-10-22 | 1991-10-22 | Silencer |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH05118489A JPH05118489A (en) | 1993-05-14 |
JP3207896B2 true JP3207896B2 (en) | 2001-09-10 |
Family
ID=17929176
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP30411291A Expired - Lifetime JP3207896B2 (en) | 1991-10-22 | 1991-10-22 | Silencer |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP3207896B2 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP6847810B2 (en) * | 2017-10-20 | 2021-03-24 | 三菱重工業株式会社 | How to manufacture heat exchangers and heat exchangers |
-
1991
- 1991-10-22 JP JP30411291A patent/JP3207896B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
JPH05118489A (en) | 1993-05-14 |
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