JP3854679B2 - Blower silencer - Google Patents

Description

【００１５】
【数２】

【００１６】
【数３】

【００１７】
【数４】

【００１８】
【数５】

【００１９】
【数６】

【００２０】
【数７】

【００２１】
【数８】

【００２２】
【数９】

【００２３】
上記各式において、（数１）〜（数４）は回転数ｎの変化に対する静圧Ｐ、風量Ｑ、軸動力Ｌの相似側、（数５）〜（数８）は羽根径Ｄの変化に対する静圧Ｐ、風量Ｑ、軸動力Ｌの相似側、（数９）は静圧Ｐ、風量Ｑ、軸動力Ｌの関係を表している。ηは効率である。以下この関係について説明する。
【００２４】
すなわち羽根車より発生する静圧Ｐは回転数ｎ1、ｎ2、に対し、（数１）の関係で表される。但し、Ｐ1は回転数ｎ1に対応する静圧、Ｐ2は回転数ｎ2に対応する静圧である。
【００２５】
ここで回転数ｎ1を基準として回転数を２倍に変化させｎ2／ｎ1＝２にすると、（数１）から静圧Ｐ2はＰ1の４倍となる。即ち、回転数を２倍にすることにより４倍の静圧を得ることができる。
【００２６】
また、羽根径Ｄと静圧Ｐとの関係は（数５）の関係で表される。但し、Ｄ1は静圧Ｐ1に対応する羽根径、Ｄ2は静圧Ｐ2に対応する羽根径である。
【００２７】
ここで羽根径Ｄ1を基準として羽根径を半分に変化させＤ2／Ｄ1＝１/２にすると、（数５）から静圧Ｐ2はＰ1の１/４倍となる。即ち、羽根径を１/２倍にすることにより１/４倍の静圧となる。
【００２８】
ここで（数１）と（数５）から、羽根径Ｄ1を基準として羽根径を変化させ、羽根径Ｄ2が１/２倍になり静圧Ｐ2が１/４になっても、回転数ｎ2をｎ1に対し２倍にすれば静圧Ｐ2をＰ1に対し４倍にできるから、同一圧力Ｐ2を発生することができることがわかる。即ち回転数に反比例した羽根径とすることができる。上記の関係は（数１）と（数５）から次の（数１０）の関係として表すことができる。
【００２９】
【数１０】

【００３０】
また風量Ｑは回転数ｎ1、ｎ2に対し（数２）の関係で表され、回転数に比例する。但し、Ｑ1は回転数ｎ1に対応する風量、Ｑ2は回転数ｎ2に対応する風量である。一方、風量Ｑは羽根径Ｄ１、Ｄ２に対しても（数６）の関係があるから、回転数ｎ、羽根径Ｄをそれぞれｎ1、Ｄ1を基準としてｎ2、Ｄ2に変化させた場合、得ることのできる風量Ｑ2は次の（数１１）の関係がある。
【００３１】
【数１１】

【００３２】
例えば回転数ｎ1に対し２倍の回転数ｎ2で運転した場合、風量Ｑ1に対し同一風量Ｑ2を得るためには、（数１１）でＱ1＝Ｑ2とおいて、次の（数１２）（数１３）の関係が得られ、羽根径Ｄは回転数ｎ1のときの羽根径Ｄ1に対し約７１％の羽根径Ｄ2とすることができる。
【００３３】
【数１２】

【００３４】
【数１３】

【００３５】
またこのときの回転数ｎ、径Ｄの変化に対する軸動力Ｌの変化は、同様に（数４）、（数８）の関係から次の（数１４）で表すことができる。
【００３６】
【数１４】

【００３７】
但しＬ1はｎ1、Ｄ1のときの軸動力、Ｌ2はｎ2、Ｄ2のときの軸動力である。
【００３８】
（数１４）において、ｎ2／ｎ1＝２、Ｄ2／Ｄ1＝０．５のときＬ2＝０．５Ｌ1となり、ｎ2／ｎ1＝２、Ｄ2／Ｄ1＝０．７１のときＬ2＝２．０Ｌ1となる。また、Ｌ2＝Ｌ1、Ｄ2／Ｄ1＝０．７１となるようにｎ2／ｎ1を求めると、ｎ2／ｎ1＝１．５８７となり、Ｌ2＝Ｌ1、ｎ2／ｎ1＝２となるようにＤ2／Ｄ1を求めるとＤ2／Ｄ1＝０．５９５となる。
【００３９】
以上の結果を（数１０）、（数１１）、（数１４）等によりまとめ、風量Ｑ−静圧Ｐの特性曲線として示したものが図２である。特性曲線▲１▼は基本性能を示す。特性曲線▲２▼はｎ2／ｎ1＝２、Ｄ2／Ｄ1＝０．５、Ｌ2＝０．５Ｌ1のときの性能を示す。特性曲線▲３▼はｎ2／ｎ1＝２、Ｄ2／Ｄ1＝０．７１、Ｌ2＝２．０Ｌ1のときの性能を示す。特性曲線▲４▼はＬ2＝Ｌ1、Ｄ2／Ｄ1＝０．７１、ｎ2／ｎ1＝１．５８７のときの性能を示す。特性曲線▲５▼はＬ2＝Ｌ1、ｎ2／ｎ1＝２、Ｄ2／Ｄ1＝０．５９５のときの性能を示す。
【００４０】
特性曲線▲２▼ではＬ2／Ｌ1＝０．５となり特性曲線▲１▼の１／２の軸動力となり、また特性曲線▲３▼では軸動力ＬはＬ2／Ｌ1＝２．０となり特性曲線▲１▼の２倍の軸動力Ｌとなる。特性曲線▲４▼、▲５▼の性能は電動機出力を変化させずに最適な小形化を図る場合に好適なプロポーションである。例えば、特性曲線▲４▼を用いた場合、理論的には電動機出力を変化しないで羽根径を７１％に下げることが可能となる。なお上記の特性に限らず、Ｑ−Ｐの特性が適用される負荷の特性などに応じて所望の特性になるように適宜この倍率を変えて最適な小形化を行うことができる。この場合回転数を増大することにより羽根径を小形化できる効果がある。また駆動用電源としては、商用電源の周波数を超える周波数を出力できる可変周波数電源、例えばインバータ装置を使うことができる。
【００４１】
本発明は上記原則に基き、羽根車１の径を比例設計にて設計したブロワとの組合せにより、消音ボックスの小形化を図ったものである。図１の渦流ブロアＶＢの実施例では、従来の渦流ブロアＶＢの回転数は商用電源周波数の例えば６０Ｈｚの場合、回転数3600rpmであったが、今回の発明の一実施例を示せば、この回転数を２倍の7200rpmとして小形化を図っている。この場合ｎ2／ｎ1＝２、Ｄ2／Ｄ1＝０．５９５となり、特性曲線▲５▼に基づくものとなる。この場合、軸動力は（数１４）で計算すれば理論的にはＬ2＝Ｌ1となるが、実際のブロアは静圧が高くなると効率が落ちるなどその他の要因で理想的な相似側にはならない。そこで実測により軸動力がほぼ同じになるように羽根径を定めることになる。その結果回転数が２倍の7200rpm（ｎ2／ｎ1＝２）で、羽根径がＤ2＝240mm（従来はＤ1=300mm）としてほぼ軸動力のほぼ等しい（即ち電動機出力のほぼ等しい）渦流ブロアＶＢが得られた。即ち電動機出力を変化しないで羽根径を８０％に下げることが可能な渦流ブロアＶＢが得られた。商用電源周波数５０Ｈｚの場合も同様に考えることができる。
【００４２】
図３、図４、図５に本発明による消音ボックスの実施例を示す。図３は内部構造を示すために一部を切断した裏面図、図４は内部構造を示すために一部を切断した左側面図、図５は内部構造を明確にするため防音カバ１３８、正面板１３９及びベース部材１２２を取外した斜視図である。
【００４３】
この消音装置１２０は主に内部構造体１３７、ベース部材１２２、防音カバー１３８、正面板１３９からなり、その外観はそれぞれが組み合わされて箱形に形成されている。ベース部材１２２の下部にはキャスタ１２４が４角に取り付けてあり、これにより全体が容易に搬送可能になっている。消音装置１２０の内部にはブロワ室１２６、消音通路室１３０、消音ダクト１３６など各種の室が隔壁によって構成してある。まず、中央部には渦流ブロアＶＢを収納するブロア室１２６を構成してある。そして、その上方には冷却風取込室１２８、および消音通路室１３０が軸方向に並列に配列して構成してある。ブロア室１２６のブロア部Ｂと反対側には冷却風導入室１３４が構成されている。１３８は防音カバー、１３９は正面板である。１４３はブロア室１２６と正面板１３９の間に位置する隔壁であり、正面板１３９との間に制御装置ＣＯＮを格納する格納室１３３を形成する。この制御装置は商用電源周波数を越える周波数を出力できるインバータ装置等の周波数変換装置を使用すれば本発明の実施に当たって好適である。この場合、従来は渦流ブロアＶＢを商用電源周波数に相当する回転数で駆動していたが、これをより高速回転するためにその出力周波数はｎ2／ｎ1に対応して商用電源周波数より高周波数化される。１４４は空間を上下に区切り、上方に冷却風取込室１２８と消音通路室１３０及び排気室１３２を形成し、下方にブロア室１２６と冷却風導入室１３４を形成する隔壁である。１４６は隔壁１４４によって、この隔壁１４４の下方に形成された空間を、軸方向で、ブロア室１２６と冷却風導入室１３４とに区切る隔壁である。１４８は防音カバー１３８の裏面側に設けた冷却風取込孔であり冷却風取込室１２８と外気とを連通する。これにより、冷却風取込室１２８には外気の冷却風が取り込まれる。１５０は隔壁１４４に設けた開口であり、冷却風取込室１２８と冷却風導入室１３４とを連通する。１５２は隔壁１４６に設けた開口であり、ブロア室１２６と冷却風導入室１３４とを連通する。この開口１５２は、ブロア室１２６に渦流ブロアＶＢを配置した状態において、渦流ブロアＶＢの冷却風取込口１１５と対応する位置に設けてある。１５６は隔壁１４４に設けた開口であり、ブロア室１２６の上方で、このブロア室１２６と排気室１３２とを連通する。１５８は防音カバー１３８に設けた排気口であり、排気室１３２と外気とを連通する。１６０は渦流ブロワＶＢの排出口１０５ａから吐き出された排気を、消音室である消音ダクト１３６に連通する配管である。１６４は渦流ブロアＶＢの吸込口１０６ａを外部の例えば負荷に接続する配管であり、防音カバー１３８、隔壁１４６を貫通して接続してある。制御装置ＣＯＮは渦流ブロワＶＢの横方向に隔壁１４３を隔てて格納室１３３に配置される。この制御装置ＣＯＮの操作パネル面は消音装置１２０の外部に面し、外から操作可能に配置されている。なお、隔壁により形成された各室の、その周壁は渦流ブロアＶＢの発生する周波数の音に対し、吸音率の高い材質、厚みを備えた吸音材１２３（斜線で囲まれた部分で示す）にて内張りされ、吸音効果を発生している。
【００４４】
以上のように構成し、渦流ブロアＶＢ、及び冷却ファン１１３による冷却風、及び渦流ブロアＶＢの排気の流れを図３，図４、図６に示してある。図６は切断平面図である。これらの図で矢印ａは冷却ファン１１３による冷却風の流れ、矢印ｂは渦流ブロアＶＢの排気の流れを示している。
【００４５】
以下、この図を参照し、渦流ブロアＶＢの排気の流れ、及び冷却ファン１１３による冷却風の流れを説明する。電動機４を駆動し、冷却ファン１１３を駆動すると、冷却風取込孔１４８から取り込まれた冷却風は、冷却ファン１１３の作用により冷却風取込室１２８に入り、開口１５０を通って冷却風導入室１３４内に至り、開口１５２からファンカバー１１４に誘導され、ファンカバー１１４に設けた冷却風取込口１１５を通り、冷却ファン１１３により渦流ブロアＶＢの冷却フィン１１６間を通って渦流ブロアＶＢを冷却する。ブロア室１２６内に供給され、冷却を終了した空気は、ブロア室１２６から開口１５６を通り排気室１３２に排出され、更に排気口１５８から排出される。矢印ａはこれによる冷却風の流れを示している。
【００４６】
一方、渦流ブロアＶＢにより、配管１６４から吸い込まれ、加圧された空気は、吐出口１０５ａから吐き出される。これは配管１６０を通って消音ダクト１３６に排出され、更にこの消音通路室１３０を通って開口１６２から排気室１３２内に排出され、更に排気口１５８から排出される。矢印ｂはこれによる空気の流れを示している。渦流ブロアＶＢによって発生する排気音は、排気が消音ダクト１３６、消音通路室１３０を通過する際に、吸音材１２３によって吸音される。開口１５６から排気された冷却ファン１１３による冷却風と開口１６２から排気された渦流ブロアＶＢによる空気は排気室１３２で合流し、排気口１５８から排気されることになる。ここでも吸音材１２３により、排気音が更に吸収される。
【００４７】
以上の構成により、従来に比べ、投影面積比６７％、体積比６３％の消音装置１２０を得ることが出来た。
【００４８】
図１２〜図１５に示す従来の消音装置では渦流ブロワＶＢからの排気を可撓性ダクト６０を通じて上部へと導き、消音ダクト３０を通じて排気室３２を通して外部へと放出していた。そのため、ダクト室３６が必ず必要となり、さらにその室内に制御装置ＣＯＮを収納せざるを得なかった。しかし本実施例によれば、ブロワの小形化により、箱体を形成する消音装置１２０の奥行寸法を、制御装置ＣＯＮを渦流ブロワＶＢの横方向に収納しても従来の奥行寸法以下とすることが可能となり、また、従来の図１２の冷却風導入室３４の位置に配管１６０及び消音ダクト１３６を配置することにより更に軸方向での小形化を図ることが可能となる。
【００４９】
図７、図８は本発明の他の実施例である。上記のようにブロワＶＢ高速化により羽根車を小形化し、制御装置ＣＯＮを渦流ブロワＶＢの側面部へ移動することが可能となり干渉するものがなくなったため、図７、図８に示すように冷却風導入室１３４にエアフィルター１７０を配置し、空気を吸込配管１７２から取り入れ、このエアフィルター１７０、配管１７４を通してブロアに送るようにすることができる。このエアフィルタは一部が前記消音装置の外部に面しており、この外部に面した位置からエアフィルタのエレメントを交換できるようになっており、メンテナンスの点で便利なように構成されている。エアフィルターを必要とする用途にはこのエアフィルタ１７０を備えた本実施例のものを使用すればコンパクトに据え付けることができる。
【００５０】
以上のように、上記実施例によれば、従来のブロワＶＢおいては排気経路の圧力損失により電動機の自冷却用の冷却ファン１１３の風量では必要換気量を満足することが出来ず、他冷却ファン５４により補助的に空気を送る必要があったが、今回高速化ブロワ採用により冷却ファン１１３の性能は、
【００５１】
【数１５】

【００５２】
【数１６】

【００５３】
となったため、ｎ2／ｎ１＝２であれば、Ｐ＝４倍、Ｑ＝２倍となり、電動機発熱量に対する風量は十分となり、従って他冷ファン５４は不要となり、更なる小形化、構造の簡便化、軽量化、低価格化を図ることが可能となった。
【００５４】
また、渦流ブロワＶＢを高速回転化することにより羽根車の回転による騒音の発生周波数は（数１７）のようになり、回転数に比例してより高周波の音を発生する様になる。
【００５５】
【数１７】

【００５６】
但し（数１７）において、Ｎｓ1はｎ1のときの発生周波数、Ｎｓ2はｎ2のときの発生周波数である。一方、抵抗形の消音装置に用いる一般的な吸音材は図９に示すとおり高周波になるほどその吸音率は高くなる。抵抗形の消音装置の吸音効果は一般に知られているように、（数１８）のような関係があり、その消音部の長さｌに比例する。上記実施例は、従来の可撓性ダクト６０の代わりに吸音材１２２を使用したダクト１３６として形成することにより消音器部を長くとることが出来減音量を大きくすることができる。したがって、高速回転になって発生する高周波化した騒音を効率良く吸収することができ、より大きな効果を得ることが出来る。
【００５７】
【数１８】

【００５８】
但し（数１８）において、Ｎｐは減音量、ｐは消音部の断面周長、Ｓは消音部の断面積、ｋは吸音率に関係した定数値である。
【００５９】
以上説明したように、上記実施例によれば、高速ブロワとの組み合わせにより、ブロワの小形化、発生音の高周波化及び消音装置の高周波吸音特性を利用してより小形、低騒音化を図ることができる。上記羽根径を２４０ｍｍとした代表機種の消音装置の寸法を示せば、幅６００ｍｍ（エアフィルター１７０と排気管、吸気管の突出部寸法含む）、奥行４８０ｍｍ（制御装置ＣＯＮの突出部寸法含む）、高さ５３５ｍｍ（キャスタの寸法含む）である。防音カバーの箱体の寸法は、幅５５０ｍｍ、奥行４４０ｍｍ、高さ４６０ｍｍであるから、エアフィルタなし、キャスタなしであれば更に小さくできる。また幅、奥行、高さの寸法比は設計的に多少変更は可能で、本発明の範囲に含まれることはいうまでもない。これにより従来に比べ、据え付けスペースに関係する床に対する投影面積を従来比６７％、以下、体積比で６３％以下の消音装置を得ることが出来た。
【００６０】
【発明の効果】
本発明によれば消音効果の高い、小形でコンパクトな消音装置を得ることが出来る。
【図面の簡単な説明】
【図１】本発明に組み合わせて使用されるブロワの一実施例の断面図である。
【図２】ブロワ性能相似則による性能曲線図である。
【図３】本発明における消音装置の一実施例を示す裏面図である。
【図４】本発明における消音装置の一実施例を示す左側面図である。
【図５】本発明における消音装置の実施例を示す分解鳥瞰図である。
【図６】本発明における消音装置内部の風の流れを示す上面図である。
【図７】本発明による消音装置の他の実施例を示す裏面図である。
【図８】本発明による消音装置の他の実施例を示す左側面図である。
【図９】吸音材の吸音率を示す図である。
【図１０】本発明による寸法効果を示す説明図である。
【図１１】従来技術によるブロワの構造を示す断面図である。
【図１２】従来技術による消音装置を示す正面図である。
【図１３】従来技術による消音装置を示す左側面図である。
【図１４】従来技術による消音装置内部の風の流れを示す正面図である。
【図１５】従来技術による消音装置内部の風の流れを示す上面図である。
【符号の説明】
ＶＢ…渦流ブロワ、
Ｍ…電動機部、
Ｂ…ブロワ部、
ＣＯＮ…制御装置、
１０１…羽根車、
１０２…ケーシング、
１０３…昇圧路、
１０３ａ…隔壁、
１０４…電動機、
１０４ｓ…回転軸、
１０５…排出側通路、
１０５ａ…排出口、
１０６…吸込側通路、
１０６ａ…吸込口、
１０８…ホイール、
１０９…環状の溝、
１１０…ハブ、
１１２…羽根、
１１３…冷却ファン、
１１４…ファンカバー、
１１５…冷却風取入口、
１１６…冷却フィン、
１２０…消音装置、
１２２…ベース部材、
１２３…吸音材、
１２４…キャスタ、
１２６…ブロア室、
１２８…冷却風取込室、
１３０…消音通路室、
１３２…排気室、
１３３…格納室、
１３４…冷却風導入室、
１３６…消音ダクト、
１３７…内部構造体、
１３８…防音カバー、
１３９…正面板、
１４３…隔壁、
１４４…隔壁、
１４６…隔壁、
１４８…冷却風取込孔、
１５０…開口、
１５２…開口、
１５６…開口、
１５８…排気口、
１６０…配管、
１６２…開口、
１６４…配管、
１７０…エアフィルタ、
１７０…吸込配管、
１７４…配管。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a silencer for a blower in which the entire blower is housed in a box having a sound absorbing material therein, and the sound generated by the blower is prevented from being released to the outside.
[0002]
[Prior art]
In recent years, various researches and developments have been conducted on the structure and shape of impellers in response to increasing demands for smaller and lighter blowers, higher discharge pressure, and lower noise. At the same time, the silencer for storing them is also required to be small and light.
[0003]
Conventionally, in this type, there is a structure in which the entire blower is housed in a box equipped with a sound absorbing material inside, and the suction port and discharge port are guided to the outside by piping. There is also a partially double structure. References for this type of technology include Japanese Patent Application Laid-Open Nos. 61-259000 and 3-253800.
[0004]
Japanese Patent Laid-Open No. 7-83199 discloses a technique for improving these. The technique described in this publication will be briefly described. FIG. 11 is a side view showing an example of a vortex blower described in the above-mentioned Japanese Patent Application Laid-Open No. 7-83199, which is partially cut away. In this figure, the vortex blower VB is composed of a blower part B and an electric motor part M that rotationally drives the blower part B. Reference numeral 1 denotes an impeller, 2 denotes a casing that forms the pressure increasing path 3, 4 denotes an electric motor that drives the impeller 1, and 4 s denotes a rotating shaft of the electric motor 4. One end of the booster passage 3 is connected to the discharge side passage 5, and the other end is connected to the suction side passage 6 which does not appear in the drawing. 5a is a discharge port, and 6a is a suction port which does not appear in the figure. The discharge side passage 5 and the suction side passage 6 are provided in parallel. The booster passage 3 is formed in an annular shape centering on the rotation center of the impeller 1, that is, the rotation shaft 4s of the electric motor 4, and has a groove shape with a semicircular arc shape that opens in a direction parallel to the rotation shaft 4s. ing. A partition wall 3 a is installed between the discharge side passage 5 and the suction side passage 6 to block the booster passage 3. The impeller 1 is fixed to the rotating shaft 4s of the electric motor 4, and has a wheel 8 that can rotate around the rotating shaft 4s and an annular shape that opens toward the booster passage 3 in a direction parallel to the rotating shaft 4s. And a plurality of blades 12 provided in the direction of dividing the annular groove 9 in the circumferential direction. . 13 is a cooling fan fixed on the opposite side of the rotating shaft 4s of the electric motor 4 from the impeller 1, 14 is a fan cover surrounding the cooling fan 13, and 15 is a cooling air intake provided in the center of the fan cover 14. It is. Reference numeral 16 denotes a cooling fin provided on the outer frame of the blower VB. When the impeller 1 is rotationally driven by the electric motor 4, the vortex blower VB sucks gas from the suction port 6 a through the suction side passage 6 by the action of the impeller 1, and sucks the sucked gas by the blade 12. The pressure is applied, guided from the hub 10 side to the pressure increasing path 3, and further returned into the hub 10 to be pressurized as a vortex. Then, it is conveyed to the discharge side passage 5. The gas pressurized to a high pressure passes through the discharge side passage 5 by the action of the partition wall 3a and is discharged from the discharge port 5a. On the other hand, as the electric motor 4 rotates, the cooling fan 13 takes in cooling air from the cooling air intake port 15 and blows it out along the cooling fins 16 to cool the vortex blower VB.
[0005]
12 and 13 are views in which a silencer is applied to the vortex blower VB of FIG. The appearance of the silencer 20 has a box shape. Reference numeral 22 is a base, 24 is a caster, 26 is a blower chamber, 28 is a cooling air intake chamber, 30 is a silence passage chamber, 32 is an exhaust chamber, 34 is a cooling air introduction chamber, 36 is a duct housing chamber, and 38 is a box. 40, 42, 44, 45 and 46 are partition walls, 48 is a cooling air intake hole, 50 is an opening provided in the partition wall 44, 52 is an opening provided in the partition wall 46, 54 is another cooling fan, 56 is an opening provided in the partition wall 40, 58 is an exhaust port communicating with the atmosphere, 60 is a flexible duct having one connected to the exhaust port 5 a and the other connected to the muffler passage 30, and 62 is provided in the partition wall 40. An opening 64 is a pipe for connecting the suction port 6 a to a load, and CON is a control device arranged in the duct housing chamber 36.
[0006]
FIGS. 14 and 15 show the flow of wind in the blower with silencer having the above-described configuration. Arrow a indicates the flow of cooling air by the other cooling fan 54, and arrow b indicates the flow of exhaust from the blower VB. According to the prior art disclosed in JP-A-7-83199, the exhaust noise of the blower can be reduced without requiring a special silencer.
[0007]
[Problems to be solved by the invention]
When storing a blower in a silencer box, the most important issues are the reduction of high-frequency sound unique to the blower due to the number of blades and countermeasures against heat generated by adiabatic compression. In the above prior art, in order to mute the rotating sound exhausted from the discharge port, a silencer is attached to the discharge port as a supplement, or a silencing structure is provided inside the muffler box to reduce the discharge sound. I'm starting to work. Further, according to the prior art disclosed in Japanese Patent Laid-Open No. 7-83199, the exhaust sound of the blower can be reduced without requiring a special silencer. In recent years, however, further downsizing has been required, but there are limitations due to the size restrictions of the blower body in order to achieve downsizing. Due to the pressure loss in the wind passage, the pressure alone is insufficient for the self-cooling fan of the motor body, so it was necessary to install another cooling fan, which had to be a more complicated internal structure.
[0008]
SUMMARY OF THE INVENTION An object of the present invention is to obtain a more compact, low-noise silencer.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is characterized in that a blower body is provided in one of the axial directions of the electric motor, a self-cooling fan is provided in the other direction, and a suction port and a discharge port are provided on the lower cooling fan side. In the blower silencer for storing a blower comprising the above, the blower is miniaturized by increasing the speed and the combination with this blower makes the silencer smaller and lighter, and the motor rotation Reduce the noise emitted by the resistance silencer using simplification of the silencer inside by using the capacity improvement of the self-cooling fan by increasing the number, and using the high frequency of the noise frequency discharged from the exhaust port Is intended.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention shown in the drawings will be described.
[0011]
FIG. 1 is a side view showing an example of a blower combined with a silencer, and a part thereof is cut away. In this figure, VB is a vortex blower. This vortex blower includes a blower part B and an electric motor part M that rotationally drives the blower part B. Reference numeral 101 denotes an impeller, reference numeral 102 denotes a casing that forms the pressure increasing path 103, reference numeral 104 denotes an electric motor that drives the impeller 101, and reference numeral 104 s denotes a rotating shaft of the electric motor 104. One end of the pressure increasing path 103 is connected to the discharge side passage 105, and the other end is connected to the suction side passage 106 which does not appear in the drawing. 105a is a discharge port, and 106a is a suction port not shown in the figure. The discharge side passage 105 and the suction side passage 106 are provided in parallel. The step-up path 103 is formed in an annular shape around the rotation center of the impeller 101, that is, the rotation shaft 104s of the electric motor 104, and has a semicircular arc-shaped groove shape that opens in a direction parallel to the rotation shaft 104s. ing. And although it does not appear in the figure, the partition 103a is installed between the discharge side passage 105 and the suction side passage 106, and the booster passage 103 is shut off similarly to the partition 3a of FIG. The impeller 101 is fixed to the rotating shaft 104s of the electric motor 104, and a wheel 108 that can rotate around the rotating shaft 104s, and an annular shape that opens toward the booster path 103 in a direction parallel to the rotating shaft 104s. A plurality of blades 112 provided in the direction of dividing the annular groove 109 in the circumferential direction. . 113 is a cooling fan fixed on the side opposite to the impeller 101 of the rotating shaft 104 s of the electric motor 104, 114 is a fan cover surrounding the cooling fan 113, and 115 is a cooling air inlet provided in the center of the fan cover 114. It is. Reference numeral 116 denotes a cooling fin provided on the outer frame of the vortex blower VB.
[0012]
In the vortex blower VB, when the impeller 101 is rotationally driven by the electric motor 104, gas is sucked from the suction port 106a through the suction side passage 106 by the action of the impeller 101, and the sucked gas is sucked by the blade 112. Pressurized, guided from the hub 110 side to the pressure increasing path 103, and further returned into the hub 110 to be pressurized as a vortex. Then, it is conveyed to the discharge side passage 105. The gas pressurized to a high pressure passes through the discharge side passage 105 by the action of the partition wall 103a and is discharged from the discharge port 105a. On the other hand, as the motor 104 rotates, the cooling fan 113 takes in the cooling air from the cooling air intake 115 and blows it out along the cooling fins 116 to cool the blower VB.
[0013]
The vortex blower VB shown in FIG. 1 uses the similar law (Equation 1) to (Equation 9) of the performance change with respect to the impeller rotational speed of the next blower compared to the conventional vortex blower VB shown in FIG. In other words, the miniaturization was achieved while exhibiting the same performance.
[0014]
[Expression 1]

[0015]
[Expression 2]

[0016]
[Equation 3]

[0017]
[Expression 4]

[0018]
[Equation 5]

[0019]
[Formula 6]

[0020]
[Expression 7]

[0021]
[Equation 8]

[0022]
[Equation 9]

[0023]
In the above formulas, (Equation 1) to (Equation 4) are the static pressure P, the air volume Q and the shaft power L with respect to the change in the rotational speed n, and (Equation 5) to (Equation 8) are the changes in the blade diameter D. (Equation 9) represents the relationship between the static pressure P, the air volume Q, and the shaft power L. η is the efficiency. This relationship will be described below.
[0024]
That is, the static pressure P generated from the impeller is expressed by the relationship of (Equation 1) with respect to the rotational speeds n1 and n2. However, P1 is a static pressure corresponding to the rotational speed n1, and P2 is a static pressure corresponding to the rotational speed n2.
[0025]
Here, when the rotational speed is changed twice with respect to the rotational speed n1, and n2 / n1 = 2, the static pressure P2 becomes four times P1 from (Equation 1). That is, a static pressure of 4 times can be obtained by doubling the rotational speed.
[0026]
Further, the relationship between the blade diameter D and the static pressure P is expressed by the relationship of (Equation 5). However, D1 is a blade diameter corresponding to the static pressure P1, and D2 is a blade diameter corresponding to the static pressure P2.
[0027]
Here, when the blade diameter is changed to half by setting the blade diameter D1 as a reference and D2 / D1 = 1/2, the static pressure P2 becomes 1/4 times P1 from (Equation 5). That is, a static pressure of 1/4 is obtained by making the blade diameter 1/2.
[0028]
Here, from (Equation 1) and (Equation 5), even if the blade diameter is changed with reference to the blade diameter D1, the rotation speed n2 even if the blade diameter D2 becomes 1/2 and the static pressure P2 becomes 1/4. It is understood that the same pressure P2 can be generated because the static pressure P2 can be increased four times with respect to P1 by doubling n1 with respect to n1. That is, the blade diameter can be inversely proportional to the rotational speed. The above relationship can be expressed as the following (Equation 10) from (Equation 1) and (Equation 5).
[0029]
[Expression 10]

[0030]
The air volume Q is expressed by the relationship of (Equation 2) with respect to the rotational speeds n1 and n2, and is proportional to the rotational speed. However, Q1 is an air volume corresponding to the rotational speed n1, and Q2 is an air volume corresponding to the rotational speed n2. On the other hand, since the air volume Q has a relation of (Equation 6) with respect to the blade diameters D1 and D2, it is obtained when the rotation speed n and the blade diameter D are changed to n2 and D2 with reference to n1 and D1, respectively. The air volume Q2 that can be produced has the following relationship (Equation 11).
[0031]
[Expression 11]

[0032]
For example, when the engine is operated at a speed n2 that is twice the speed n1, in order to obtain the same air quantity Q2 with respect to the air quantity Q1, Q1 = Q2 in (Equation 11) and the following (Equation 12) (Equation 13 The blade diameter D can be about 71% of the blade diameter D2 with respect to the blade diameter D1 at the rotation speed n1.
[0033]
[Expression 12]

[0034]
[Formula 13]

[0035]
Further, the change of the shaft power L with respect to the change of the rotation speed n and the diameter D at this time can be similarly expressed by the following (Equation 14) from the relationship of (Equation 4) and (Equation 8).
[0036]
[Expression 14]

[0037]
However, L1 is a shaft power when n1 and D1, and L2 is a shaft power when n2 and D2.
[0038]
In (Expression 14), when n2 / n1 = 2 and D2 / D1 = 0.5, L2 = 0.5L1, and when n2 / n1 = 2 and D2 / D1 = 0.71, L2 = 2.0L1. . Further, when n2 / n1 is obtained so that L2 = L1 and D2 / D1 = 0.71, n2 / n1 = 1.588, and D2 / D1 is set so that L2 = L1, n2 / n1 = 2. When calculated, D2 / D1 = 0.595.
[0039]
FIG. 2 shows the above results summarized as (Equation 10), (Equation 11), (Equation 14), etc., and shown as a characteristic curve of air volume Q-static pressure P. The characteristic curve (1) shows the basic performance. The characteristic curve {circle over (2)} shows the performance when n2 / n1 = 2, D2 / D1 = 0.5, and L2 = 0.5L1. The characteristic curve (3) shows the performance when n2 / n1 = 2, D2 / D1 = 0.71, and L2 = 2.0L1. The characteristic curve (4) shows the performance when L2 = L1, D2 / D1 = 0.71, and n2 / n1 = 1.588. The characteristic curve (5) shows the performance when L2 = L1, n2 / n1 = 2, and D2 / D1 = 0.595.
[0040]
In the characteristic curve {circle over (2)}, L2 / L1 = 0.5, which is half the shaft power of the characteristic curve {circle around (1)}, and in the characteristic curve {circle over (3)}, the shaft power L becomes L2 / L1 = 2.0 and the characteristic curve ▲ The shaft power L is twice that of 1 ▼. The performance of the characteristic curves (4) and (5) is a proportion suitable for achieving an optimal miniaturization without changing the motor output. For example, when the characteristic curve (4) is used, it is theoretically possible to reduce the blade diameter to 71% without changing the motor output. Not only the above-described characteristics, but also an appropriate miniaturization can be performed by appropriately changing this magnification so as to obtain a desired characteristic in accordance with a load characteristic to which the QP characteristic is applied. In this case, there is an effect that the blade diameter can be reduced by increasing the rotational speed. As the driving power source, a variable frequency power source capable of outputting a frequency exceeding the frequency of the commercial power source, for example, an inverter device can be used.
[0041]
Based on the above principle, the present invention aims to reduce the size of the muffler box by combining with the blower designed with the proportional design of the diameter of the impeller 1. In the embodiment of the vortex blower VB in FIG. 1, the rotation speed of the conventional vortex blower VB is 3600 rpm when the commercial power supply frequency is 60 Hz, for example. The number has been reduced to 7200 rpm, which is doubled. In this case, n2 / n1 = 2 and D2 / D1 = 0.595, which are based on the characteristic curve (5). In this case, if the shaft power is calculated by (Equation 14), L2 = L1 theoretically, but the actual blower does not become the ideal similarity side due to other factors such as a decrease in efficiency when the static pressure increases. . Therefore, the blade diameter is determined so that the shaft power is substantially the same by actual measurement. As a result, the rotational speed is doubled to 7200 rpm (n2 / n1 = 2), the blade diameter is D2 = 240 mm (conventionally D1 = 300 mm), and the vortex blower VB has substantially the same shaft power (that is, the motor output is almost equal). Obtained. That is, the vortex blower VB capable of reducing the blade diameter to 80% without changing the motor output was obtained. The same can be considered for a commercial power supply frequency of 50 Hz.
[0042]
FIG. 3, FIG. 4 and FIG. 5 show an embodiment of a silence box according to the present invention. 3 is a rear view with a part cut to show the internal structure, FIG. 4 is a left side view with a part cut to show the internal structure, and FIG. It is the perspective view which removed the face plate 139 and the base member 122. FIG.
[0043]
The silencer 120 mainly includes an internal structure 137, a base member 122, a soundproof cover 138, and a front plate 139, and the appearances thereof are combined to form a box shape. Casters 124 are attached to the lower part of the base member 122 at four corners, so that the whole can be easily conveyed. Inside the silencer 120, various chambers such as a blower chamber 126, a silencer passage chamber 130, and a silencer duct 136 are constituted by partition walls. First, a blower chamber 126 that houses the vortex blower VB is formed in the center. Above that, the cooling air intake chamber 128 and the muffler passage chamber 130 are arranged in parallel in the axial direction. A cooling air introduction chamber 134 is formed on the side of the blower chamber 126 opposite to the blower portion B. Reference numeral 138 denotes a soundproof cover, and 139 denotes a front plate. A partition wall 143 is located between the blower chamber 126 and the front plate 139, and forms a storage chamber 133 for storing the control device CON between the front plate 139. This control device is suitable for implementing the present invention if a frequency conversion device such as an inverter device capable of outputting a frequency exceeding the commercial power supply frequency is used. In this case, the vortex blower VB has been conventionally driven at a rotational speed corresponding to the commercial power supply frequency, but in order to rotate it at a higher speed, its output frequency is higher than the commercial power supply frequency corresponding to n2 / n1. Is done. Reference numeral 144 denotes a partition wall that divides the space up and down, forms a cooling air intake chamber 128, a muffler passage chamber 130, and an exhaust chamber 132 in the upper portion, and forms a blower chamber 126 and a cooling air introduction chamber 134 in the lower portion. A partition wall 146 divides a space formed below the partition wall 144 into a blower chamber 126 and a cooling air introduction chamber 134 in the axial direction by the partition wall 144. Reference numeral 148 denotes a cooling air intake hole provided on the back surface side of the soundproof cover 138, which communicates the cooling air intake chamber 128 with the outside air. Thereby, the cooling air of the outside air is taken into the cooling air intake chamber 128. An opening 150 is provided in the partition wall 144, and communicates the cooling air intake chamber 128 and the cooling air introduction chamber 134. An opening 152 is provided in the partition wall 146 and connects the blower chamber 126 and the cooling air introduction chamber 134. The opening 152 is provided at a position corresponding to the cooling air intake port 115 of the vortex blower VB when the vortex blower VB is disposed in the blower chamber 126. Reference numeral 156 denotes an opening provided in the partition wall 144, which connects the blower chamber 126 and the exhaust chamber 132 above the blower chamber 126. Reference numeral 158 denotes an exhaust port provided in the soundproof cover 138, which communicates the exhaust chamber 132 with the outside air. A pipe 160 communicates the exhaust discharged from the discharge port 105a of the vortex blower VB to a silencer duct 136 serving as a silencer chamber. A pipe 164 connects the suction port 106a of the vortex blower VB to an external load, for example, and is connected through the soundproof cover 138 and the partition 146. The control device CON is arranged in the storage chamber 133 with a partition wall 143 in the lateral direction of the vortex blower VB. The operation panel surface of the control device CON faces the outside of the silencer 120 and is arranged to be operable from the outside. It should be noted that the peripheral wall of each chamber formed by the partition wall is made of a sound absorbing material 123 (shown by a portion surrounded by oblique lines) having a high sound absorption coefficient and thickness with respect to the sound of the frequency generated by the vortex flow blower VB. It is lined and generates a sound absorbing effect.
[0044]
The vortex blower VB, the cooling air from the cooling fan 113, and the flow of the exhaust air from the vortex blower VB are shown in FIG. 3, FIG. 4, and FIG. FIG. 6 is a cut plan view. In these drawings, arrow a indicates the flow of cooling air from the cooling fan 113, and arrow b indicates the flow of exhaust air from the vortex blower VB.
[0045]
Hereinafter, the flow of exhaust air from the vortex blower VB and the flow of cooling air from the cooling fan 113 will be described with reference to this figure. When the motor 4 is driven and the cooling fan 113 is driven, the cooling air taken in from the cooling air intake hole 148 enters the cooling air intake chamber 128 by the action of the cooling fan 113 and is introduced through the opening 150. It reaches the inside of the chamber 134, is guided to the fan cover 114 from the opening 152, passes through the cooling air intake port 115 provided in the fan cover 114, and passes between the cooling fins 116 of the vortex blower VB by the cooling fan 113. Cooling. The air that has been supplied into the blower chamber 126 and has finished cooling is discharged from the blower chamber 126 to the exhaust chamber 132 through the opening 156 and further discharged from the exhaust port 158. Arrow a shows the flow of cooling air.
[0046]
On the other hand, the air sucked from the pipe 164 and pressurized by the vortex blower VB is discharged from the discharge port 105a. This is discharged through the pipe 160 to the muffler duct 136, further discharged through the muffler passage chamber 130 from the opening 162 into the exhaust chamber 132, and further discharged from the exhaust port 158. The arrow b shows the air flow by this. The exhaust sound generated by the vortex blower VB is absorbed by the sound absorbing material 123 when the exhaust passes through the silencer duct 136 and the silencer passage chamber 130. Cooling air from the cooling fan 113 exhausted from the opening 156 and air from the vortex blower VB exhausted from the opening 162 merge in the exhaust chamber 132 and are exhausted from the exhaust port 158. Also here, the sound absorption material 123 further absorbs the exhaust sound.
[0047]
With the above configuration, it was possible to obtain the silencer 120 having a projected area ratio of 67% and a volume ratio of 63% compared to the conventional case.
[0048]
In the conventional silencer shown in FIGS. 12 to 15, the exhaust from the vortex blower VB is guided upward through the flexible duct 60 and discharged to the outside through the exhaust chamber 32 through the silencer duct 30. For this reason, the duct chamber 36 is indispensable, and the control device CON must be accommodated in the chamber. However, according to the present embodiment, due to the downsizing of the blower, the depth dimension of the silencer 120 that forms the box body is made smaller than the conventional depth dimension even if the control device CON is housed in the lateral direction of the vortex blower VB. Further, by disposing the pipe 160 and the silencer duct 136 at the position of the conventional cooling air introduction chamber 34 of FIG. 12, it is possible to further reduce the size in the axial direction.
[0049]
7 and 8 show another embodiment of the present invention. As described above, the speed of the blower VB is increased to reduce the size of the impeller, and the controller CON can be moved to the side surface of the vortex blower VB so that there is no interference. An air filter 170 may be disposed in the introduction chamber 134, and air may be taken from the suction pipe 172 and sent to the blower through the air filter 170 and the pipe 174. Part of this air filter faces the outside of the silencer, and the elements of the air filter can be exchanged from the position facing the outside, so that it is convenient in terms of maintenance. . If the air filter 170 according to this embodiment including the air filter 170 is used for an application that requires an air filter, the air filter can be installed compactly.
[0050]
As described above, according to the above-described embodiment, in the conventional blower VB, the required airflow cannot be satisfied by the airflow of the cooling fan 113 for self-cooling the motor due to the pressure loss in the exhaust path, and the other cooling Although it was necessary to send air supplementarily by the fan 54, the performance of the cooling fan 113 by using the high speed blower this time is
[0051]
[Expression 15]

[0052]
[Expression 16]

[0053]
Therefore, if n2 / n1 = 2, P = 4 times and Q = 2 times, and the air flow with respect to the motor heat generation amount is sufficient, so that the other cooling fan 54 becomes unnecessary, and further downsizing and simple structure are possible. It has become possible to reduce the weight and weight.
[0054]
Further, by generating a high-speed rotation of the vortex blower VB, the noise generation frequency due to the rotation of the impeller becomes (Expression 17), and a higher frequency sound is generated in proportion to the rotation speed.
[0055]
[Expression 17]

[0056]
However, in (Equation 17), Ns1 is a generated frequency when n1, and Ns2 is a generated frequency when n2. On the other hand, a general sound-absorbing material used in a resistance-type silencer has a higher sound absorption rate as the frequency becomes higher as shown in FIG. As is generally known, the sound absorbing effect of the resistance-type silencer has a relationship of (Equation 18) and is proportional to the length l of the silencer. In the above embodiment, by forming the duct 136 using the sound absorbing material 122 instead of the conventional flexible duct 60, the muffler portion can be made longer and the volume reduction can be increased. Therefore, high frequency noise generated by high speed rotation can be efficiently absorbed, and a greater effect can be obtained.
[0057]
[Formula 18]

[0058]
In (Equation 18), Np is the volume reduction, p is the cross-sectional circumferential length of the silencer, S is the cross-sectional area of the silencer, and k is a constant value related to the sound absorption coefficient.
[0059]
As described above, according to the above embodiment, by combining with a high speed blower, it is possible to reduce the size of the blower, increase the frequency of generated sound, and reduce the noise by using the high frequency sound absorption characteristics of the silencer. Can do. If the dimensions of the silencer of the representative model with the blade diameter of 240 mm are shown, the width is 600 mm (including the air filter 170 and the exhaust pipe and the intake pipe projecting dimensions), the depth is 480 mm (including the projecting dimension of the control device CON), The height is 535 mm (including the caster dimensions). Since the dimensions of the soundproof cover box are 550 mm in width, 440 mm in depth, and 460 mm in height, it can be further reduced without air filters and casters. Needless to say, the dimensional ratio of width, depth, and height can be slightly changed in design, and is included in the scope of the present invention. As a result, it was possible to obtain a silencer having a projected area with respect to the floor related to the installation space of 67% compared to the prior art, and a volume ratio of 63% or less.
[0060]
【The invention's effect】
According to the present invention, it is possible to obtain a compact and compact silencer having a high noise reduction effect.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an embodiment of a blower used in combination with the present invention.
FIG. 2 is a performance curve diagram according to a blower performance similarity rule.
FIG. 3 is a back view showing one embodiment of the silencer according to the present invention.
FIG. 4 is a left side view showing an embodiment of a silencer according to the present invention.
FIG. 5 is an exploded bird's-eye view showing an embodiment of a silencer according to the present invention.
FIG. 6 is a top view showing the flow of wind inside the silencer according to the present invention.
FIG. 7 is a rear view showing another embodiment of the silencer according to the present invention.
FIG. 8 is a left side view showing another embodiment of the silencer according to the present invention.
FIG. 9 is a diagram showing a sound absorption coefficient of a sound absorbing material.
FIG. 10 is an explanatory diagram showing a dimensional effect according to the present invention.
FIG. 11 is a cross-sectional view showing the structure of a blower according to the prior art.
FIG. 12 is a front view showing a silencer according to the prior art.
FIG. 13 is a left side view showing a silencer according to the prior art.
FIG. 14 is a front view showing the flow of wind inside the silencer according to the prior art.
FIG. 15 is a top view showing the flow of wind inside the silencer according to the prior art.
[Explanation of symbols]
VB ... Eddy current blower,
M ... Electric motor part,
B ... Blower section,
CON: Control device,
101 ... impeller,
102 ... casing,
103: Booster path,
103a ... partition wall,
104: Electric motor,
104s ... rotation axis,
105 ... discharge side passage,
105a ... discharge port,
106 ... suction side passage,
106a ... Suction port,
108 ... wheel,
109 ... An annular groove,
110 ... Hub,
112 ... feathers,
113 ... Cooling fan,
114 ... Fan cover,
115 ... Cooling air inlet,
116 ... cooling fins,
120 ... silencer,
122 ... Base member,
123 ... Sound absorbing material,
124 ... Casters,
126 ... Blower room,
128 ... Cooling air intake chamber,
130 ... Silent passage room,
132 ... exhaust chamber,
133 ... the storage room,
134 ... cooling air introduction chamber,
136 ... Silencer duct,
137 ... internal structure,
138 ... Soundproof cover,
139 ... Front plate,
143 ... partition wall,
144 ... partition wall,
146 ... partition wall,
148 ... Cooling air intake hole,
150 ... opening,
152 ... opening,
156 ... opening,
158 ... exhaust port,
160 ... piping,
162 ... opening,
164 ... Piping,
170: air filter,
170 ... Suction piping,
174 ... Piping.

Claims (1)

Blower part B on one side in the axial direction of electric motor M,
On the other hand, a cooling fan 113 for self-cooling,
A blower silencer 120 having a vortex blower VB provided with a suction port 106a and a discharge port 105a at a lower part on the cooling fan 113 side,
The electric motor M is driven at a frequency exceeding the commercial power supply frequency, rotated at 7200 revolutions per minute, and the blade 101 diameter is 240 mm,
In the silencer 120 of the blower that absorbs the generated sound, which has been increased in frequency with the increase in the rotation frequency of the blower part B, using a resistance-type silencer structure,
The silencer 120 includes a base member 122, a soundproof cover 138, and a front plate 139, which are combined to form a box shape.
Inside the silencer 120, each chamber of the blower chamber 126, the silencer passage chamber 130, and the silencer duct 136 is constituted by a partition wall 143, a partition wall 144, and a partition wall 146.
A blower chamber 126 that houses the vortex blower VB is configured at the center of the silencer 120,
Above that, a muffler passage chamber 130 is arranged in the axial direction,
There is a partition wall 143 located between the blower chamber 126 and the front plate 139,
In addition, there is a partition wall 144 that vertically divides the space in the silencer 120, forms a silencer passage chamber 130 and an exhaust chamber 132 above, and forms a blower chamber 126 and a cooling air introduction chamber 134 below.
There is a partition wall 146 that divides the space formed below the partition wall 144 into the blower chamber 126 and the cooling air introduction chamber 134 in the axial direction,
The peripheral walls of the blower chamber 126, the muffler passage chamber 130, and the muffler duct 136 formed by the partition wall 143, the partition wall 144, and the partition wall 146 are about 0 with respect to the sound of the frequency generated by the vortex flow blower VB. . Lined with a sound absorbing material 123 having a sound absorption coefficient of 8 or more, producing a sound absorbing effect,
The air sucked and pressurized from the pipe 164 by the vortex blower VB is discharged from the discharge port 105a, discharged through the pipe 160 to the silencer duct 136, and further exhausted from the opening 162 through the silencer passage chamber 130. Discharged into the chamber 132 and further discharged from the exhaust port 158,
The exhaust sound generated by the vortex blower VB is absorbed by the sound absorbing material 123 when the exhaust passes through the silencer duct 136 and the silencer passage chamber 130.
Further, a control device CON having a frequency conversion device capable of outputting a frequency exceeding the commercial power supply frequency is stored in a storage chamber 133 formed between the partition wall 143 and the front plate 139.
In addition, the piping 160 and the silencer duct 136 are arranged in the cooling air introduction chamber 34,
Also, a blower silencer, wherein an air filter 170 is disposed in the cooling air introduction chamber 134.

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