JP3608223B2

JP3608223B2 - Immersion membrane separator

Info

Publication number: JP3608223B2
Application number: JP18194894A
Authority: JP
Inventors: 繁樹沢田; 和夫今井
Original assignee: Kurita Water Industries Ltd
Current assignee: Kurita Water Industries Ltd
Priority date: 1994-07-12
Filing date: 1994-07-12
Publication date: 2005-01-05
Anticipated expiration: 2020-01-05
Also published as: JPH0824597A

Description

【０００１】
【産業上の利用分野】
本発明は、原液中に吹き出した空気により膜表面のケーク層等の成長を抑制したり、剥離したり、或は膜表面を清浄化するようにした浸漬型膜分離装置に関するものである。
【０００２】
【従来の技術】
浸漬型膜分離装置は、図７に示すように、膜エレメント１を浸漬した浸漬槽２内の水深に基づく水頭差を利用し、吸引ポンプ３により低エネルギーで膜分離を行い、透過水を得ることができる。
この様な浸漬型膜分離装置においては、例えば特開平１−２９３１０３号公報に記載されているように、浸漬槽２内の下部に曝気管４の空気吹出口５を配置し、この吹出口５から吹き出される気泡６が原液内を上昇することにより原液に水流を発生させて膜分離能率を高めるとともに、上昇する気泡が膜の表面に接触するときの衝撃により膜面の付着層の成長を抑制する。
【０００３】
【発明が解決しようとする課題】
膜エレメントの下部に気泡を発生させるには、曝気装置が必要であり、また、均等に膜エレメント間に気泡を分散させるには膜エレメントの下方の深い位置から曝気する必要があった。このため、膜エレメントを浸漬するのに必要な深さだけでは不充分であり、気泡が均等に分散するために要する深さを加えた浸漬槽を使用しなければならない。しかし、浸漬槽を深くすると、過剰な水槽容量となってしまい、無駄が生じ、また、装置が大きく嵩張るという不都合も生じる。
また、膜面に付着するケーキ層を剥離できるようにするには、大量の空気を間歇的に放出しなければならない。したがって、大きなブロワー或はコンプレッサーを必要とし、また、停止時のために自動弁を設けなければならず、装置全体が大型化し構造も複雑になってしまう。
そこで、本発明は、浸漬槽を深くすることなく、しかも少ない空気で膜面の付着層の成長を効率良く抑制できる浸漬型膜分離装置を提供しようとするものである。
【０００４】
【課題を解決するための手段】
請求項１に記載の発明は、浸漬槽内に膜エレメントを浸漬して分離処理を行う浸漬型膜分離装置において、空気サイホン室を膜エレメントを構成する膜の下方に設け、空気サイホン室に空気供給管を接続し、空気サイホン室内に溜った空気を一瞬のうちに空気吹出口から間歇的に吹き出させ、該空気吹出口から吹き出す気泡の塊と膜とを接触させるようにし、膜エレメントを所定の間隔を空けて浸漬槽内に複数浸漬するとともに、各膜エレメントの両側の膜の下方に空気吹出口を各膜の全幅わたってそれぞれ開口するようにしたことを特徴とする浸漬型膜分離装置である。
【０００５】
また、請求項２に記載の発明は、浸漬槽内に膜エレメントを浸漬して分離処理を行う浸漬型膜分離装置において、空気サイホン室を膜エレメントを構成する膜の下方に設け、空気サイホン室に空気供給管を接続し、空気サイホン室内に溜った空気を一瞬のうちに空気吹出口から間歇的に吹き出させ、該空気吹出口から吹き出す気泡の塊と膜とを接触させるようにし、膜エレメントを所定の間隔を空けて複数浸漬するとともに、空気吹出口を膜エレメントの幅の約半分とし、浸漬槽に設置する場合には空気吹出口が隣りの膜エレメントの空気吹出口が開口していない部分に向く様に、膜エレメントの向きを交互に組み合せて取り付け、隣りの膜エレメントの空気吹出口から吹き出された空気の気泡によって、各膜の全幅にわたって気泡の塊を接触させることを特徴とする浸漬型膜分離装置である。
また、請求項３に記載の発明は、請求項１または２において、前記空気サイホン室は、下端に液流入口を開設した第１室と、該第１室と上端連通口で連通した第２室と、該第２室と下端連通口で連通して上端に空気吹出口を開設した第３室とからなり、下端連通口の開口縁の上端を液流入口の開口位置よりも高い位置に設定したものであることを特徴とする浸漬型膜分離装置である。
【０００６】
【実施例】
以下、本発明の実施例を図面にもとづいて説明する。
図１は浸漬槽１１内に所定の間隔を空けて複数浸漬される膜エレメント１２の斜視図である。この膜エレメント１２は、内部に透過水室１３を幅方向に形成した膜支持板１４と、この膜支持板１４の両側の面に張設した膜１５と、膜支持板１４の左右両端縁に取り付けた集水管１６と、膜１５の下端縁に沿って設けた空気サイホン室１７などからなり、この集水管１６に膜支持板１４の透過水室１３が連通し、集水管１６の上端に接続した透過水取出管１８から透過水を取り出すように構成してある。
【０００７】
膜支持板１４は、ポリプロピレンや、ＡＢＳ樹脂等のプラスチック成型品であり、二枚の平板１９を所定の間隔を空けてほぼ平行に配置し、両平板１９の間に左右方向に長尺な障壁２０を所定の上下間隔で複数平行に配設して両平板と障壁２０とを一体化するとともに、両平板と上下の障壁２０とに囲まれて左右方向に延在する透過水室１３を上下多段に形成し、平板１９には小さな透過水集水孔２１を開設してある。したがって、膜支持板１４は、上下の端面が障壁２０により密閉され、左右の端面に透過水室１３の開口部が開口し、両側の平板１９に透過水集水孔２１が透過水室１３に沿って多数開口している。
【０００８】
空気サイホン室１７の基本的な構造は、下端に液流入口２２を開設した第１室２３と、該第１室２３と上端連通口２４で連通した第２室２５と、該第２室２５と下端連通口２６で連通して上端に空気吹出口２７を開設した第３室２８とからなり、下端連通口２６の開口縁の上端を液流入口２２の開口位置よりも高い位置に設定したものであり、本実施例では、膜エレメント１２の下端縁の全幅に集水管１６と同じ厚さで空気サイホン室１７が形成されている。
【０００９】
具体的には、図２に示すように、膜支持板１４の下端面側から垂設した第１上仕切壁２９と、この第１上仕切壁２９に対して所定の間隔を空けて平行な状態で垂設した第２上仕切壁３０と、底面の両側縁から第１下仕切壁３１と第２下仕切壁３２を立設した２本の樋状底部材３３とからなり、両樋状底部材３３の各第１下仕切壁３１を上記第１上仕切壁２９と第２上仕切壁３０との間の間隙内に下方から挿入して一方の第２下仕切壁３２を第１上仕切壁２９の外側に、他方の第２下仕切壁３２を第２上仕切壁３０の外側に位置させ、それぞれの仕切壁間には所定の間隔を確保し、また、上仕切壁の下端縁は樋状底部材３３の底面から離隔し、下仕切壁の上端縁も膜支持板１４の下端面から離隔させる。
【００１０】
この様に構成すると、両第１下仕切壁３１の間に第１室２３が形成されて両第１下仕切壁３１基端間の開口部が液流入口２２となり、一方の第１下仕切壁３１と第１上仕切壁２９との間及び他方の第１下仕切壁３１と第２上仕切壁３０との間の空間が第２室２５となり、第１上仕切壁２９と一方の第２下仕切壁３２との間に第３室２８が形成されて当該第２下仕切壁３２の上端縁と膜支持板１４下縁との間の横長スリット状の開口部が空気吹出口２７として開口するとともに、第２上仕切壁３０と他方の第２下仕切壁３２との間に第３室２８が形成されて当該第２下仕切壁３２の上端縁と膜支持板１４下縁との間の横長スリット状の開口部が空気吹出口２７として開口する。
【００１１】
そして、各第２室２５は、各第１下仕切壁３１の上端縁と支持板１４下端面との間に形成された上端連通口２４で上部が第１室２３の上部と連通する。また、第３室２８は、第１上仕切壁２９の下端縁と樋状底部材３３の底面との間に形成された下端連通口２６で下部が第２室２５の下端と連通する。
【００１２】
また、第２室２５の下部と第３室２８の下部を連通する下端連通口２６の上端は、上仕切壁の下端縁が樋状底部材３３の底面から離隔しているので、両樋状底部材３３の底面側縁間に形成された液流入口２２よりも高い位置に位置する。
【００１３】
なお、上記した第１室２３，第２室２５，第３室２８の端部開口部は閉塞壁３４により一括して閉塞されている。そして、この閉塞壁３４に開設した空気供給口に空気供給管３５を接続して該空気供給管３５を第１室２３に連通する。
【００１４】
また、上記した構成からなる空気サイホン室１７を設けた膜エレメント１２を浸漬槽１１内に浸漬して空気供給管３５から圧縮空気を第１室２３に圧送すると、図３（Ａ）に示すように、第１室２３と第２室２５の上部に次第に空気が貯留される。この貯留空気の量が次第に増加すると、空気圧により第１室２３内の原液が液流入口２２から空気サイホン室１７の外部に押し出されて第１室２３内の液面が次第に下降する。また、第２室２５内の原液も空気圧に押し下げられて第３室２８に流入して第２室２５内の液面が次第に下降し、第３室２８内の原液は第２室２５から流入してきた原液に押されて空気吹出口２７からその分だけ空気サイホン室１７の外部に押し出される。なお、第１室２３内の液面と第２室２５内の液面は、第１室２３と第２室２５とが空気サイホン室１７の外部で原液中で連通しているので、同じ高さ（レベル）である。
【００１５】
貯留空気の量がさらに増加すると、第１室２３内の液面が更に下降するとともに、第２室２５内の液面も更に同じだけ下降する。そして、継続して供給される空気によって第１室２３と第２室２５の両液面が更に下降して、遂には第２室２５内の液面が下端連通口２６の開口縁の上端まで下降し、この液面が下端連通口２６の開口縁の上端よりも下降した時点でこの空気が下端連通口２６を通って第３室２８内に流入し、一方この時点でも第１室２３内の液面は液流入口２２よりも高い位置にある。したがって、上記のようにして第１室２３内と第２室２５内の液面が次第に下降しても、第２室２５内の空気が第３室２８に流入する前に第１室２３内の空気が液流入口２２から流出することはない。
【００１６】
第２室２５から下端連通口２６を通って第３室２８内に空気が流入すると、この空気は第３室２８内を上昇して空気吹出口２７から空気サイホン室１７の外部に吹き出す。このとき、第３室２８内を空気が上昇すると、気泡ポンプの原理と同様に、上昇する気泡が第３室２８内の原液を揚送して気泡と共に空気吹出口２７から排出する。また、第２室２５から第３室２８に空気が逃げて、この空気が第３室２８内を上昇して第２室２５内の空気の圧力が減少すると、液流入口２２から原液が第１室２３内に流入して第１室２３内の液面が上昇する。したがって、下端連通口２６では第２室２５内の空気が第３室２８内に流れ込み易い圧力関係になり、図３（Ｃ）に示すように、第１室２３と第２室２５内に溜って貯留していた空気が一瞬にして空気吹出口２７から吹き出し、第１室２３内には液流入口２２から原液が流入し、この原液は上端連通口２４から第２室２５内にも流入していく。
【００１７】
この様にして空気サイホン室１７内に溜っていた空気が一瞬のうちに空気吹出口２７から吹き出して気泡となると、この気泡は、図４にしめすように、並べて浸漬された膜エレメント１２間の流路を満たした塊となって膜面に沿って上昇する。
【００１８】
気泡の塊が膜面に沿って上昇すると、膜面に空気と原液の界面が発生し、この界面が上昇するときに大きな剪断力が膜面に生じ、この剪断力によって膜面に形成されているケーキ層が剥離する。したがって、膜面が浄化される。
【００１９】
また、本実施例では各膜エレメント１２の両側の膜の下部に空気吹出口２７が全幅わたってそれぞれに開口しているので、各膜１５の全面にわたって均等に気泡の塊を発生させることができる。したがって、膜エレメント１２が浸漬できる深さを有する浸漬槽１１であればよく、従来の曝気式浸漬槽１１よりも浅くて足りる。
【００２０】
空気サイホン室１７内には空気供給管３５を介して継続して圧縮空気が供給されるので、溜った空気が一度吹き出しても、その後に供給された空気が次第に貯留され、第２室２５内の液面が下端連通口２６の開口縁の上端を過ぎた時点で再び空気吹出口２７から空気が吹き出される。したがって、各膜エレメント１２の空気吹出口２７からは間歇的に空気が吹き出されることとなり、膜面は、この間歇吹き出しする気泡の塊によって繰り返し浄化される。
【００２１】
上記した第１の実施例では空気サイホン室１７を膜エレメント１２の下部に膜エレメントの厚み方向に２組設けて空気吹出口２７を膜１５の全幅にわたって開口したが、本発明はこれに限定されるものではない。例えば、図５に示す第２の実施例の様に、膜エレメント１２の下部に空気サイホン室１７を１つ設けて、空気吹出口２７を膜の約片半に開口してもよい。
【００２２】
この空気サイホン室１７は、膜エレメント１２の幅のほぼ中央に上仕切壁３７を設けて２分した一方の室を第３室２８として上端に空気吹出口２７開設し、他方の室を更にほぼ中央の下仕切壁３８により２分して第３室２８側を第２室２５、残りの室を第１室２３とし、第１室２３の底面に液流入口２２を開設したものである。なお、第１室２３と第２室２５とは下仕切壁３８の上端を途中で止めて形成した上端連通口２４で連通し、第２室２５と第３室２８とは上仕切壁３７の下端を途中で止めて形成した下端連通口２６で連通し、下端連通口２６の開口縁の上端を液流入口２２の開口位置よりも高く位置するように構成し、第１室２３の側面に空気供給管３５を接続する。
【００２３】
したがって、空気供給管３５を介して第１室２３内に圧縮空気を圧送すると、第１室２３と第２室２５内の上部に空気が溜り、両室内の液面が貯留空気の増加と共に下降し、第２室２５内の液面が上仕切壁３７の下端よりも下がると、溜っていた空気が第３室２８に流れ込んで空気吹出口２７から一瞬の内に吹き出す。吹き出した空気の気泡は塊となって上昇し、膜面を洗浄する。
【００２４】
本実施例では空気吹出口２７が膜エレメント１２の幅の約半分なので、浸漬槽１１に設置する場合には、空気吹出口２７が隣りの膜エレメント１２の第１室２３と第２室２５（即ち、空気吹出口２７が開口していない部分）に向く様に、膜エレメント１２の向きを交互に組み合せて取り付ける。この様に配置すれば、空気吹出口２７が膜エレメント１２の幅の約半分であっても、隣りの膜エレメント１２の空気吹出口２７から吹き出された空気の気泡によって、各膜１５の全幅にわたって気泡の塊を接触させることができる。
【００２５】
また、本発明は、各膜エレメント１２自体に空気サイホン室１７を設ける必要はなく、膜１５の下方に空気サイホン室１７が位置すれば良い。例えば、図６に示す浸漬型膜分離装置の他の実施例は、浸漬槽１１の下部に２組みの空気サイホン室１７を間隔を空けて浸漬槽１１の長手方向に沿って設け、この長尺な空気サイホン室１７間の上方に複数の膜エレメント１２を所定間隔で並べて設けたものである。
【００２６】
この実施例に示す空気サイホン室１７は、下部に液通過開口部３９を有し、上部に平行な第４，第５下仕切壁４０，４１を有する略上向き樋状下部材４２と、上面から平行な第４，第５上仕切壁４３，４４を有する略下向き樋状上部材４５とを組み合せて、第４上仕切壁４３と第４下仕切壁４０との間に第１室２３を、第４下仕切壁４０と第５上仕切壁４４との間に第２室２５を、第５上仕切壁４４と第５下仕切壁４１との間に第３室２８を形成したもので、第４下仕切壁４０の上端縁を下向き樋状上部材４５の上面から離隔することにより上端連通口２４を形成して第１室２３と第２室２５とを各室上端で連通し、第５上仕切壁４４の下端縁を上向き樋状下部材４２の底面から離隔することにより下端連通口２６を形成して第２室２５と第３室２８とを各室下端で連通し、第１室２３の下端に液流入口２２を開設し、第３室２８の上端に空気吹出口２７を開設し、下端連通口２６の開口縁の上端を液流入口２２の開口位置よりも高い位置に設定し、第１室２３に空気供給管３５を接続してある。また、両空気サイホン室１７の空気吹出口２７は向き合わせてある。
【００２７】
したがって、空気供給管３５を介して第１室２３内に圧縮空気を圧送すると、第１室２３と第２室２５内の上部に空気が溜り、両室内の液面が貯留空気の増加と共に下降し、第２室２５内の液面が上仕切壁の下端よりも下がると、溜っていた空気が第３室２８に流れ込んで空気吹出口２７から一瞬の内に吹き出す。この空気の吹き出しは、前述した実施例と同様に間歇的に行われ、吹き出した空気の気泡は塊となって上昇し、膜エレメント１２の下端に当ると分れて膜エレメント１２間に形成された流路３６内を上昇して両側の膜面を清浄する。そして、図６中右側に示した空気サイホン室１７の空気吹出口２７から吹き出した気泡は主として膜エレメント１２の膜面の右半を、左側に示した空気サイホン室１７の空気吹出口２７から吹き出した気泡は主として膜エレメント１２の膜面の左半を清浄することとなり、両空気吹出口２７から吹き出される気泡によって膜面の全面が清浄される。また、空気吹出口２７から吹き出した気泡は、膜面に接触することなく水面まで上昇してしまうことがない。したがって、少ない空気量で効率良く膜面のケーキ層を剥離することができる。
【００２８】
また、本実施例では左右の空気吹出口２７から気泡が吹き出されて膜エレメント１２間の流路３６を上昇するので、この気泡の上昇によって浸漬槽１１内に図６中矢印で示すように、膜エレメント１２の下方から上昇して、膜エレメント１２間を通過した水流は左右に分れて下降し、液通過開口部３９を通って再度膜エレメント１２間を通過する循環流が発生する。したがって、この循環流の発生により一層濾過効率を高めることができる。なお、循環流を確実にするために、膜エレメント１２の両側には整流板４６を立設することが望ましい。
【００２９】
尚、本発明の浸漬型膜分離装置の好ましい態様としては、浸漬槽内に膜エレメントを浸漬して分離処理を行う浸漬型膜分離装置において、空気サイホン室を膜エレメントを構成する膜の下方に設け、空気サイホン室に空気供給管を接続し、空気サイホン室内に溜った空気を一瞬のうちに空気吹出口から間歇的に吹き出させ、該空気吹出口から吹き出す気泡の塊と膜とを接触させるようにし、膜エレメントを所定の間隔を空けて浸漬槽内に複数浸漬するとともに、各膜エレメントの両側の膜の下方に空気吹出口を各膜の全幅わたってそれぞれ開口するようにしたことを特徴とする浸漬型膜分離装置、
浸漬槽内に膜エレメントを浸漬して分離処理を行う浸漬型膜分離装置において、空気サイホン室を膜エレメントを構成する膜の下方に設け、空気サイホン室に空気供給管を接続し、空気サイホン室内に溜った空気を一瞬のうちに空気吹出口から間歇的に吹き出させ、該空気吹出口から吹き出す気泡の塊と膜とを接触させるようにし、膜エレメントを所定の間隔を空けて複数浸漬するとともに、空気吹出口を膜エレメントの幅の約半分とし、浸漬槽に設置する場合には空気吹出口が隣りの膜エレメントの空気吹出口が開口していない部分に向く様に、膜エレメントの向きを交互に組み合せて取り付け、隣りの膜エレメントの空気吹出口から吹き出された空気の気泡によって、各膜の全幅にわたって気泡の塊を接触させることを特徴とする浸漬型膜分離装置、および、上記のいずれかの構成において、前記空気サイホン室は、下端に液流入口を開設した第１室と、該第１室と上端連通口で連通した第２室と、該第２室と下端連通口で連通して上端に空気吹出口を開設した第３室とからなり、下端連通口の開口縁の上端を液流入口の開口位置よりも高い位置に設定したものであることを特徴とする浸漬型膜分離装置がある。
【００３０】
【発明の効果】
以上説明したように本発明によれば、膜の下方に開設した空気吹出口から間歇的に空気が吹き出され、この気泡の塊が膜エレメント間の流路に沿って上昇するので、吹き出された空気が確実に膜面に接触し、吹き出された空気が膜面に接触することなく無駄に上昇してしまうことを防止することができる。したがって、少ない空気であっても膜面を効率良く清浄することができる。また、間歇的に吹き出させるので、気泡の塊となって膜面に接触する際の剪断力が強く、少ない空気であっても膜面のケーキ層を強力に剥離することができる。
また、上昇途中で分散させて気泡を膜エレメントに均等に接触させることなく、吹出口から吹き出した気泡がそのまま均等に膜面に接触するので、膜エレメントが浸漬するに必要な深さを有する浸漬槽であれば足り、従来の浸漬槽よりも浅い水槽を使用でき、過剰容量の浸漬装置は不要である。したがって、装置全体を従来よりも小型化することができる。
【図面の簡単な説明】
【図１】下部に空気サイホン室を一体的に設けた膜エレメントの一部欠截斜視図である。
【図２】図１に示す空気サイホン室の断面図である。
【図３】（Ａ）は第１室と第２室に空気が溜った状態の空気サイホン室の断面図、（Ｂ）は吹出口から空気が吹き出す直前の状態を示す空気サイホン室の断面図、（Ｃ）は吹出口から空気が吹き出した状態を示す空気サイホン室の断面図である。
【図４】吹き出した気泡が膜エレメント間の流路内を上昇している状態を示す浸漬型膜分離装置の断面図である。
【図５】膜エレメントの幅の約半分の吹出口を開設した空気サイホン室の正面図である。
【図６】膜エレメントとは別個に浸漬槽の底部に空気サイホン室を設けた実施例の断面図である。
【図７】従来の浸漬型膜分離装置の断面図である。
【符号の説明】
１１浸漬槽
１２膜エレメント
１４膜支持板
１５膜
１６集水管
１７空気サイホン室
２２液流入口
２３第１室
２４上端連通口
２５第２室
２６下端連通口
２７空気吹出口
２８第３室
２９第１上仕切壁
３０第２上仕切壁
３１第１下仕切壁
３２第２下仕切壁
３３樋状底部材
３５空気供給管
３６流路
３７上仕切壁
３８下仕切壁
４０第４下仕切壁
４１第５下仕切壁
４２樋状下部材
４３第４上仕切壁
４４第５上仕切壁
４５樋状上部材
４６整流板[0001]
[Industrial application fields]
The present invention relates to a submerged membrane separation apparatus in which the growth of a cake layer or the like on the membrane surface is suppressed, peeled off, or the membrane surface is cleaned by air blown into a stock solution.
[0002]
[Prior art]
As shown in FIG. 7, the submerged membrane separator uses a water head difference based on the water depth in the immersion tank 2 in which the membrane element 1 is immersed, and performs membrane separation with low energy by the suction pump 3 to obtain permeated water. be able to.
In such a submerged membrane separation apparatus, for example, as described in JP-A-1-293103, an air outlet 5 of an aeration tube 4 is disposed at a lower portion in the immersion tank 2, and the outlet 5 The bubbles 6 blown out from the liquid rise in the stock solution to generate a water flow in the stock solution to increase the membrane separation efficiency, and the adhesion layer on the membrane surface grows by impact when the rising bubbles come into contact with the membrane surface. Suppress.
[0003]
[Problems to be solved by the invention]
In order to generate bubbles at the lower part of the membrane element, an aeration apparatus is required, and in order to uniformly disperse the bubbles between the membrane elements, it is necessary to aerate from a deep position below the membrane element. For this reason, the depth required to immerse the membrane element is not sufficient, and a dip bath to which the depth required for air bubbles to be uniformly dispersed must be used. However, if the immersion tank is deepened, the capacity of the water tank becomes excessive, resulting in waste and inconvenience that the apparatus is bulky.
Moreover, in order to be able to peel the cake layer adhering to the film surface, a large amount of air must be intermittently released. Therefore, a large blower or a compressor is required, and an automatic valve must be provided for stopping, resulting in a large apparatus and a complicated structure.
Therefore, the present invention is intended to provide an immersion type membrane separation apparatus that can efficiently suppress the growth of the adhesion layer on the membrane surface with a small amount of air without deepening the immersion tank.
[0004]
[Means for Solving the Problems]
According to the first aspect of the present invention, in the immersion type membrane separation apparatus that performs the separation process by immersing the membrane element in the immersion tank, the air siphon chamber is provided below the membrane constituting the membrane element, and the air siphon chamber is A supply pipe is connected, and the air accumulated in the air siphon chamber is intermittently blown out from the air blowout outlet in an instant, so that the lump of bubbles blown out from the air blowout outlet is brought into contact with the membrane, and the membrane element is fixed. A submerged type membrane separation apparatus characterized in that a plurality of pieces are immersed in a dipping tank with an interval of and an air outlet is opened across the entire width of each membrane below the membrane on both sides of each membrane element. It is.
[0005]
According to a second aspect of the present invention, in the submerged membrane separation apparatus that performs the separation process by immersing the membrane element in the immersion tank, the air siphon chamber is provided below the membrane constituting the membrane element, and the air siphon chamber The air supply pipe is connected to the air element so that the air accumulated in the air siphon chamber is intermittently blown out from the air blowout port in an instant, and the mass of bubbles blown out from the air blowout port is brought into contact with the membrane element. Is immersed in a plurality at predetermined intervals, the air outlet is about half the width of the membrane element, and when installed in the immersion tank, the air outlet of the adjacent membrane element is not open The membrane elements are installed in alternate orientations so that they face each other, and air bubbles blown out from the air outlets of the adjacent membrane elements connect the bubble mass over the entire width of each membrane. It is a submerged membrane separator, wherein for.
The invention according to claim 3 is the air chamber according to claim 1 or 2, wherein the air siphon chamber is a first chamber having a liquid inlet at a lower end thereof, and a second chamber communicated with the first chamber through an upper end communication port. And a third chamber that communicates with the second chamber at the lower end communication port and opens an air outlet at the upper end, and the upper end of the opening edge of the lower end communication port is positioned higher than the opening position of the liquid inlet An immersion type membrane separator characterized by being set.
[0006]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view of a membrane element 12 that is immersed in the immersion tank 11 at a predetermined interval. The membrane element 12 includes a membrane support plate 14 having a permeate chamber 13 formed in the width direction therein, a membrane 15 stretched on both sides of the membrane support plate 14, and left and right edges of the membrane support plate 14. It consists of an attached water collecting pipe 16 and an air siphon chamber 17 provided along the lower edge of the membrane 15. The water collecting tube 16 communicates with the permeated water chamber 13 of the membrane support plate 14 and is connected to the upper end of the water collecting pipe 16. The permeated water is extracted from the permeated water outlet pipe 18.
[0007]
The membrane support plate 14 is a plastic molded product such as polypropylene or ABS resin, and two flat plates 19 are arranged substantially in parallel at a predetermined interval, and a barrier that is long in the left-right direction between the two flat plates 19. The flat plate 20 and the barrier 20 are integrated by arranging a plurality of the plates 20 in parallel at predetermined vertical intervals, and the permeated water chamber 13 extending in the left-right direction is surrounded by the flat plates and the upper and lower barriers 20. It is formed in multiple stages, and a small permeate collecting hole 21 is formed in the flat plate 19. Therefore, the upper and lower end surfaces of the membrane support plate 14 are sealed by the barriers 20, the openings of the permeate chamber 13 are opened on the left and right end surfaces, and the permeate water collecting holes 21 are formed in the flat plates 19 on both sides. There are many openings along.
[0008]
The basic structure of the air siphon chamber 17 includes a first chamber 23 having a liquid inlet 22 at the lower end, a second chamber 25 communicating with the first chamber 23 through an upper end communication port 24, and the second chamber 25. And a third chamber 28 having an air outlet 27 opened at the upper end communicating with the lower end communication port 26. The upper end of the opening edge of the lower end communication port 26 is set at a position higher than the opening position of the liquid inlet 22. In this embodiment, the air siphon chamber 17 is formed in the same width as the water collecting pipe 16 over the entire width of the lower end edge of the membrane element 12.
[0009]
Specifically, as shown in FIG. 2, the first upper partition wall 29 suspended from the lower end surface side of the membrane support plate 14 is parallel to the first upper partition wall 29 with a predetermined interval. A second upper partition wall 30 suspended in the state, and two bowl-shaped bottom members 33 each having a first lower partition wall 31 and a second lower partition wall 32 erected from both side edges of the bottom surface. Each first lower partition wall 31 of the bottom member 33 is inserted into the gap between the first upper partition wall 29 and the second upper partition wall 30 from below, and one of the second lower partition walls 32 is inserted into the first upper wall. The other second lower partition wall 32 is positioned outside the second upper partition wall 30 on the outside of the partition wall 29, a predetermined interval is secured between the partition walls, and the lower end edge of the upper partition wall Is separated from the bottom surface of the bowl-shaped bottom member 33, and the upper end edge of the lower partition wall is also separated from the lower end surface of the membrane support plate 14.
[0010]
If comprised in this way, the 1st chamber 23 will be formed between both the 1st lower partition walls 31, and the opening part between both 1st lower partition walls 31 will become the liquid inflow port 22, and one 1st lower partition The space between the wall 31 and the first upper partition wall 29 and between the other first lower partition wall 31 and the second upper partition wall 30 is the second chamber 25, and the first upper partition wall 29 and one of the first partition walls The third chamber 28 is formed between the two lower partition walls 32, and a horizontally long slit-shaped opening between the upper edge of the second lower partition wall 32 and the lower edge of the membrane support plate 14 serves as the air outlet 27. In addition to opening, a third chamber 28 is formed between the second upper partition wall 30 and the other second lower partition wall 32 so that the upper edge of the second lower partition wall 32 and the lower edge of the membrane support plate 14 A horizontally elongated slit-shaped opening in between is opened as an air outlet 27.
[0011]
Each second chamber 25 communicates with the upper portion of the first chamber 23 at the upper end communication port 24 formed between the upper end edge of each first lower partition wall 31 and the lower end surface of the support plate 14. The lower portion of the third chamber 28 communicates with the lower end of the second chamber 25 at a lower end communication port 26 formed between the lower end edge of the first upper partition wall 29 and the bottom surface of the bowl-shaped bottom member 33.
[0012]
In addition, since the lower end edge of the upper partition wall is separated from the bottom surface of the bowl-shaped bottom member 33, the upper end of the lower end communication port 26 that communicates the lower part of the second chamber 25 and the lower part of the third chamber 28 is formed in a bilateral shape. It is located at a position higher than the liquid inlet 22 formed between the bottom side edges of the bottom member 33.
[0013]
Note that the end openings of the first chamber 23, the second chamber 25, and the third chamber 28 are collectively blocked by the blocking wall 34. Then, an air supply pipe 35 is connected to the air supply port opened in the closed wall 34 so that the air supply pipe 35 communicates with the first chamber 23.
[0014]
When the membrane element 12 provided with the air siphon chamber 17 having the above-described configuration is immersed in the immersion tank 11 and compressed air is pumped from the air supply pipe 35 to the first chamber 23, as shown in FIG. In addition, air is gradually stored in the upper portions of the first chamber 23 and the second chamber 25. When the amount of the stored air gradually increases, the stock solution in the first chamber 23 is pushed out from the liquid inlet 22 to the outside of the air siphon chamber 17 by the air pressure, and the liquid level in the first chamber 23 gradually falls. Also, the stock solution in the second chamber 25 is pushed down by the air pressure and flows into the third chamber 28, the liquid level in the second chamber 25 gradually falls, and the stock solution in the third chamber 28 flows from the second chamber 25. It is pushed by the undiluted solution and is pushed out of the air siphon chamber 17 from the air outlet 27 by that amount. The liquid level in the first chamber 23 and the liquid level in the second chamber 25 are the same because the first chamber 23 and the second chamber 25 communicate with each other in the stock solution outside the air siphon chamber 17. It is (level).
[0015]
When the amount of stored air further increases, the liquid level in the first chamber 23 further decreases, and the liquid level in the second chamber 25 also decreases by the same amount. The liquid levels in the first chamber 23 and the second chamber 25 are further lowered by the continuously supplied air, and finally the liquid level in the second chamber 25 reaches the upper end of the opening edge of the lower end communication port 26. When the liquid level drops and the liquid level falls below the upper end of the opening edge of the lower end communication port 26, the air flows into the third chamber 28 through the lower end communication port 26. The liquid level is higher than the liquid inlet 22. Therefore, even if the liquid level in the first chamber 23 and the second chamber 25 gradually falls as described above, the air in the first chamber 23 is not allowed to flow into the third chamber 28 before the air in the second chamber 25 flows into the third chamber 28. The air does not flow out from the liquid inlet 22.
[0016]
When air flows into the third chamber 28 from the second chamber 25 through the lower end communication port 26, this air rises in the third chamber 28 and blows out from the air siphon chamber 17 through the air outlet 27. At this time, when the air rises in the third chamber 28, the rising bubbles lift the stock solution in the third chamber 28 and discharge it from the air outlet 27 together with the bubbles, as in the principle of the bubble pump. Further, when air escapes from the second chamber 25 to the third chamber 28 and this air rises in the third chamber 28 and the pressure of the air in the second chamber 25 decreases, the stock solution is supplied from the liquid inlet 22 to the first chamber. The liquid flows into the first chamber 23 and the liquid level in the first chamber 23 rises. Therefore, the lower end communication port 26 has a pressure relationship in which the air in the second chamber 25 easily flows into the third chamber 28 and accumulates in the first chamber 23 and the second chamber 25 as shown in FIG. The air stored in the air blows out from the air outlet 27 in an instant, and the stock solution flows into the first chamber 23 from the liquid inlet 22. The stock solution also flows into the second chamber 25 from the upper end communication port 24. I will do it.
[0017]
When the air accumulated in the air siphon chamber 17 in this way blows out from the air outlet 27 in an instant and becomes bubbles, the bubbles are formed between the membrane elements 12 immersed side by side as shown in FIG. It becomes a lump that fills the flow path and rises along the film surface.
[0018]
When the bubble mass rises along the membrane surface, an interface of air and stock solution is generated on the membrane surface, and when this interface rises, a large shearing force is generated on the membrane surface, which is formed on the membrane surface by this shearing force. The cake layer is peeled off. Therefore, the film surface is purified.
[0019]
Further, in the present embodiment, since the air outlets 27 are opened across the entire width of the lower portions of the membranes on both sides of each membrane element 12, bubbles of bubbles can be generated uniformly over the entire surface of each membrane 15. . Therefore, the immersion tank 11 may have a depth that allows the membrane element 12 to be immersed, and may be shallower than the conventional aeration immersion tank 11.
[0020]
Since compressed air is continuously supplied into the air siphon chamber 17 via the air supply pipe 35, even if the accumulated air is blown out once, the air supplied thereafter is gradually stored, and the second chamber 25 The air is blown out again from the air outlet 27 when the liquid level passes the upper end of the opening edge of the lower end communication port 26. Therefore, air is intermittently blown out from the air outlet 27 of each membrane element 12, and the membrane surface is repeatedly purified by the lump of bubbles that blow out intermittently.
[0021]
In the first embodiment described above, two sets of air siphon chambers 17 are provided in the thickness direction of the membrane element below the membrane element 12 and the air outlets 27 are opened over the entire width of the membrane 15. However, the present invention is limited to this. It is not something. For example, as in the second embodiment shown in FIG. 5, one air siphon chamber 17 may be provided at the lower part of the membrane element 12, and the air outlet 27 may be opened in about one half of the membrane.
[0022]
This air siphon chamber 17 is provided with an upper partition wall 37 in the middle of the width of the membrane element 12 and one chamber divided into two is a third chamber 28 with an air outlet 27 at the upper end, and the other chamber is further approximately The third chamber 28 side is divided into two by the central lower partition wall 38, the remaining chamber is the first chamber 23, and the liquid inlet 22 is opened at the bottom of the first chamber 23. The first chamber 23 and the second chamber 25 communicate with each other through an upper end communication port 24 formed by stopping the upper end of the lower partition wall 38 in the middle, and the second chamber 25 and the third chamber 28 communicate with the upper partition wall 37. The lower end communication port 26 formed by stopping the lower end is communicated, and the upper end of the opening edge of the lower end communication port 26 is configured to be positioned higher than the opening position of the liquid inlet port 22. An air supply pipe 35 is connected.
[0023]
Therefore, when compressed air is pumped into the first chamber 23 via the air supply pipe 35, air accumulates in the upper portions of the first chamber 23 and the second chamber 25, and the liquid level in both chambers decreases with the increase in stored air. When the liquid level in the second chamber 25 falls below the lower end of the upper partition wall 37, the accumulated air flows into the third chamber 28 and blows out from the air outlet 27 instantly. The blown air bubbles rise as a lump and clean the membrane surface.
[0024]
In the present embodiment, since the air outlet 27 is about half the width of the membrane element 12, when the air outlet 27 is installed in the immersion tank 11, the air outlet 27 has the first chamber 23 and the second chamber 25 ( In other words, the membrane elements 12 are attached by alternately combining the directions so that the air outlets 27 are directed to the portions where the air outlets 27 are not open. If arranged in this way, even if the air outlet 27 is about half the width of the membrane element 12, the air bubbles blown out from the air outlet 27 of the adjacent membrane element 12 will cover the entire width of each membrane 15. Bubble mass can be brought into contact.
[0025]
In the present invention, it is not necessary to provide the air siphon chamber 17 in each membrane element 12 itself, and the air siphon chamber 17 may be positioned below the membrane 15. For example, in another embodiment of the submerged membrane separation apparatus shown in FIG. 6, two sets of air siphon chambers 17 are provided in the lower part of the immersion tank 11 along the longitudinal direction of the immersion tank 11 with a space therebetween. A plurality of membrane elements 12 are arranged above the air siphon chambers 17 at predetermined intervals.
[0026]
The air siphon chamber 17 shown in this embodiment has a substantially upward bowl-shaped lower member 42 having a liquid passage opening 39 in the lower portion and fourth and fifth lower partition walls 40 and 41 parallel to the upper portion, and an upper surface. The first chamber 23 is formed between the fourth upper partition wall 43 and the fourth lower partition wall 40 by combining the substantially downward-facing bowl-shaped upper member 45 having the fourth and fifth upper partition walls 43 and 44 in parallel. The second chamber 25 is formed between the fourth lower partition wall 40 and the fifth upper partition wall 44, and the third chamber 28 is formed between the fifth upper partition wall 44 and the fifth lower partition wall 41, The upper end communication port 24 is formed by separating the upper end edge of the fourth lower partition wall 40 from the upper surface of the downward bowl-shaped upper member 45 so that the first chamber 23 and the second chamber 25 communicate with each other at the upper end of each chamber. 5 The lower end communication port 26 is formed by separating the lower end edge of the upper partition wall 44 from the bottom surface of the upward hooked lower member 42 to form the second chamber 25 and the The chambers 28 communicate with each other at the lower end, the liquid inlet 22 is opened at the lower end of the first chamber 23, the air outlet 27 is opened at the upper end of the third chamber 28, and the upper end of the opening edge of the lower end communicating port 26. Is set at a position higher than the opening position of the liquid inlet 22, and an air supply pipe 35 is connected to the first chamber 23. Further, the air outlets 27 of the two air siphon chambers 17 face each other.
[0027]
Therefore, when compressed air is pumped into the first chamber 23 via the air supply pipe 35, air accumulates in the upper portions of the first chamber 23 and the second chamber 25, and the liquid level in both chambers decreases with the increase in stored air. When the liquid level in the second chamber 25 falls below the lower end of the upper partition wall, the accumulated air flows into the third chamber 28 and blows out from the air outlet 27 in an instant. This air blowing is performed intermittently in the same manner as in the above-described embodiment, and the bubbles of the blown air rise as a lump and are formed between the membrane elements 12 when they hit the lower end of the membrane element 12. The inside of the flow path 36 is lifted to clean the membrane surfaces on both sides. The bubbles blown out from the air outlet 27 of the air siphon chamber 17 shown on the right side in FIG. 6 mainly blow out the right half of the membrane surface of the membrane element 12 from the air outlet 27 of the air siphon chamber 17 shown on the left side. The air bubbles mainly clean the left half of the membrane surface of the membrane element 12, and the entire surface of the membrane surface is cleaned by the bubbles blown from both the air outlets 27. Further, the bubbles blown out from the air outlet 27 do not rise to the water surface without contacting the film surface. Therefore, the cake layer on the film surface can be efficiently peeled with a small amount of air.
[0028]
Further, in the present embodiment, bubbles are blown out from the left and right air outlets 27 and the flow path 36 between the membrane elements 12 is raised, and as shown by arrows in FIG. The water flow that rises from below the membrane element 12 and passes between the membrane elements 12 falls to the left and right, and a circulating flow that passes between the membrane elements 12 again through the liquid passage opening 39 is generated. Therefore, the filtration efficiency can be further enhanced by the generation of this circulation flow. In order to ensure the circulation flow, it is desirable to erect the rectifying plates 46 on both sides of the membrane element 12.
[0029]
In addition, as a preferable aspect of the submerged membrane separation apparatus of the present invention, in the submerged membrane separator that performs the separation treatment by immersing the membrane element in the immersion tank, the air siphon chamber is located below the membrane constituting the membrane element. The air supply pipe is connected to the air siphon chamber, and the air accumulated in the air siphon chamber is intermittently blown out from the air outlet in an instant, and the lump of bubbles blown out from the air outlet is brought into contact with the film. A plurality of membrane elements are immersed in the immersion tank at predetermined intervals, and air outlets are opened across the entire width of each membrane below the membranes on both sides of each membrane element. Submerged membrane separation device,
In a submerged membrane separation apparatus that performs a separation process by immersing a membrane element in an immersion tank, an air siphon chamber is provided below the membrane constituting the membrane element, an air supply pipe is connected to the air siphon chamber, and the air siphon chamber The air accumulated in the air is blown intermittently from the air outlet, and the mass of bubbles blown out from the air outlet is brought into contact with the membrane, and a plurality of membrane elements are immersed at predetermined intervals. If the air outlet is about half the width of the membrane element and installed in the immersion tank, the orientation of the membrane element should be such that the air outlet faces the part where the air outlet of the adjacent membrane element is not open. Immersion type, characterized in that a mass of bubbles is brought into contact with the entire width of each membrane by air bubbles blown out from the air outlet of the adjacent membrane element. In the separator and any one of the configurations described above, the air siphon chamber includes a first chamber having a liquid inlet at a lower end, a second chamber in communication with the first chamber through an upper end communication port, It consists of two chambers and a third chamber that opens at the upper end and communicates with the lower end communication port. The upper end of the opening edge of the lower end communication port is set at a position higher than the opening position of the liquid inlet. There is a submerged membrane separator characterized by this.
[0030]
【The invention's effect】
As described above, according to the present invention, air is intermittently blown out from the air blower opening formed below the membrane, and the lump of bubbles rises along the flow path between the membrane elements. It is possible to prevent the air from coming into contact with the film surface reliably, and the blown-out air from rising unnecessarily without contacting the film surface. Therefore, the film surface can be efficiently cleaned even with a small amount of air. Moreover, since it blows intermittently, the shear force at the time of contacting a film surface as a lump of bubbles is strong, and the cake layer on the film surface can be strongly peeled even with a small amount of air.
In addition, since the bubbles blown out from the blowout outlet are uniformly contacted with the membrane surface without being dispersed evenly in the middle of ascending and the bubbles are in contact with the membrane element, the membrane element has a depth necessary for immersion. A tank is sufficient, and a shallower water tank than the conventional immersion tank can be used, and an excessive volume immersion apparatus is unnecessary. Therefore, the entire apparatus can be made smaller than before.
[Brief description of the drawings]
FIG. 1 is a partially cutaway perspective view of a membrane element in which an air siphon chamber is integrally provided at a lower portion.
FIG. 2 is a cross-sectional view of the air siphon chamber shown in FIG.
3A is a cross-sectional view of an air siphon chamber in a state where air is accumulated in the first chamber and the second chamber, and FIG. 3B is a cross-sectional view of the air siphon chamber showing a state immediately before air is blown out from the air outlet. (C) is sectional drawing of the air siphon chamber which shows the state which the air blew out from the blower outlet.
FIG. 4 is a cross-sectional view of a submerged membrane separation device showing a state where blown bubbles are rising in a flow path between membrane elements.
FIG. 5 is a front view of an air siphon chamber in which an air outlet having about half the width of the membrane element is opened.
FIG. 6 is a cross-sectional view of an embodiment in which an air siphon chamber is provided at the bottom of the immersion tank separately from the membrane element.
FIG. 7 is a cross-sectional view of a conventional immersion type membrane separation apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Immersion tank 12 Membrane element 14 Membrane support plate 15 Membrane 16 Water collecting pipe 17 Air siphon chamber 22 Liquid inlet 23 First chamber 24 Upper end communication port 25 Second chamber 26 Lower end communication port 27 Air outlet 28 Third chamber 29 First Upper partition wall 30 Second upper partition wall 31 First lower partition wall 32 Second lower partition wall 33 Bowl-shaped bottom member 35 Air supply pipe 36 Channel 37 Upper partition wall 38 Lower partition wall 40 Fourth lower partition wall 41 Fifth The lower partition wall 42 The bowl-shaped lower member 43 The fourth upper partition wall 44 The fifth upper partition wall 45 The bowl-shaped upper member 46 The current plate

Claims

In a submerged membrane separation apparatus that performs a separation process by immersing a membrane element in an immersion tank, an air siphon chamber is provided below the membrane constituting the membrane element, an air supply pipe is connected to the air siphon chamber, and the air siphon chamber The air accumulated in the air is blown intermittently from the air outlet, and the mass of bubbles blown out from the air outlet is brought into contact with the membrane, and the membrane element is placed in the immersion tank at a predetermined interval. A submerged membrane separation apparatus characterized in that a plurality of soaking and an air outlet are opened across the entire width of each membrane below the membrane on both sides of each membrane element.

In a submerged membrane separation apparatus that performs a separation process by immersing a membrane element in an immersion tank, an air siphon chamber is provided below the membrane constituting the membrane element, an air supply pipe is connected to the air siphon chamber, and the air siphon chamber The air accumulated in the air is blown intermittently from the air outlet, and the mass of bubbles blown out from the air outlet is brought into contact with the membrane, and a plurality of membrane elements are immersed at predetermined intervals. If the air outlet is about half the width of the membrane element and installed in the immersion tank, the orientation of the membrane element should be such that the air outlet faces the part where the air outlet of the adjacent membrane element is not open. Immersion type, characterized in that a mass of bubbles is brought into contact over the entire width of each membrane by air bubbles blown out from the air outlet of the adjacent membrane element. Separation device.

3. The air siphon chamber according to claim 1, wherein the air siphon chamber has a first chamber having a liquid inlet at a lower end, a second chamber communicated with the first chamber through an upper end communication port, and the second chamber and a lower end communication port. And a third chamber in which an air outlet is opened at the upper end and the upper end of the opening edge of the lower end communication port is set at a position higher than the opening position of the liquid inlet. Mold membrane separator.