JP3944723B2

JP3944723B2 - Screw press with concentration function

Info

Publication number: JP3944723B2
Application number: JP2002230259A
Authority: JP
Inventors: 謙三菅谷; 幸利三谷; 雅義片山; 伸夫本田
Original assignee: Ishigaki Co Ltd
Current assignee: Ishigaki Co Ltd
Priority date: 2002-08-07
Filing date: 2002-08-07
Publication date: 2007-07-18
Anticipated expiration: 2022-08-07
Also published as: JP2004066306A

Description

【０００１】
【発明の属する技術分野】
この発明は、濃縮ゾーンとろ過・脱水ゾーンに分割して、外筒とスクリュー軸を回転自在に配設したスクリュープレスに関し、詳しくは、固形物負荷よりも水負荷の大きい濃度の低い汚泥でも、目詰まりを防止しながら濃縮脱水を可能として、脱水ケーキの含水率を均一化させるスクリュープレスの改良に関する。
【０００２】
【従来の技術】
従来、下水、し尿、あるいは食品生産加工廃水等の有機性汚泥は高分子凝集剤を添加してフロックを生成させている。濃度の低い有機性汚泥は遠心濃縮機や浮上濃縮機により濃縮してろ過脱水する方法がとられている。これらの濃縮装置は、例えば１％の濃度の汚泥を４〜５％に濃縮し、この濃縮汚泥をスクリュープレスでろ過・脱水している。これらの装置は、いずれも設置面積が大きくなり、駆動電力費や高分子凝集剤の費用などが高くつき、維持管理においても面倒であった。濃度の低い有機性汚泥を直接スクリュープレスで濃縮、脱水させると、スクリュープレスの汚泥注入側では汚泥濃度が低いため、濃縮ゾーンの外筒スクリーンでは固形物負荷よりも水負荷が大きく、外筒スクリーンから多量の水を排出する必要がある。特に、高分子凝集剤によって高分子薄膜が発生し、濃縮ゾーンにおいては外筒のスクリーンに残渣が付着して目詰まりが発生しやすい。
【０００３】
従来の外筒回転型のスクリュープレスとしては、ろ過円筒を汚泥注入側と排出側に中間部で分割し、汚泥注入側のスクリュー羽根のピッチ間隔を狭くして、汚泥注入側のろ過円筒を移送スクリューの回転速度よりも遅い速度で回転させ、ホッパーから供給した汚泥をろ過・脱水しながら、円筒の外部から高圧流体を噴射して、この円筒の微細孔に付着したケーキ層を洗浄し、ろ過脱水効果を継続的に維持させるスクリュープレスは、例えば、特公平３−７８１２３号公報に記載してあるように公知である。また、出口側に向ってピッチ間隔を狭くしたスクリュー羽根を巻き付けた回転スクリューをスクリーンドラムと逆方向に回転させながら、回転スクリューの軸部から汚泥などをスクリーンドラムに供給して、大量の水分を分離する装置も、例えば、特開２０００−３３４９５号公報に記載してあるように公知である。
【０００４】
【発明が解決しようとする課題】
上記汚泥注入側のろ過円筒を強制回転させるスクリュープレスにあっては、スクリュー羽根がろ過円筒の摺接回数を増加させ、スクリーン面を再生できるものであり、外筒を回転させながら連続して洗浄水を噴射することでスクリーンの目詰まり防止効果が得られるものであるが、排出側のろ過円筒の目詰まりは洗浄水だけではスクリーン面の再生が困難であった。また、連続洗浄のため多くの洗浄水が必要となっていた。そして、ホッパーより供給する凝集汚泥はフロックが壊れやすく、壊れた微細粒子がスクリーンから分離液とともに排出され、充分な性能が発揮できなかった。
【０００５】
また、上記スクリュー羽根のケーキ排出側のピッチ間隔を狭くして凝集汚泥をポンプで軸心から供給するスクリュープレスにあっては、初期ゾーンの圧密度を高めることができるものであり、スクリーンドラムを回転スクリューと逆方向に回転させることにより、濃縮ゾーンの外筒スクリーンの再生が可能となるものであるが、ピッチ間隔が狭くなる排出側の外筒のスクリーンから軟弱なケーキが抜け出す恐れがあり、目詰まりが早期に発生する欠点があった。
上記従来の外筒回転型のスクリュープレスにあっては、スクリュー羽根の表面と裏面のケーキの水分差により、排出される脱水ケーキの含水率にバラツキがあり、脱水ケーキのコンポスト化や焼却の後処理に支障を来していた。この発明は、スクリュープレスの汚泥注入側のろ過円筒を回転させながらろ過・脱水を行なう従来技術を応用し、ろ過円筒の汚泥注入側を濃縮ゾーンとして、高分子凝集剤で凝集させた濃度の低い有機汚泥でも、外筒スクリーンの目詰まりを防止して、濃縮とろ過・脱水を可能とし、最終の脱水ケーキを調整ゾーンで均質化させるスクリュープレスを提供する。
【０００６】
【課題を解決するための手段】
この発明の要旨は、スクリュー羽根を巻き掛けたスクリュー軸を外筒に配設し、外筒とスクリュー軸の間のろ過室を供給側から脱水側に向って相対的に減少させ、ろ過室の始端部に供給した汚泥を、スクリュー軸を回転させながら外筒のスクリーンからろ液を排出して、ろ過室の終端部からケーキを取出すスクリュープレスにおいて、上記外筒に中間軸受を配設して、スクリュー軸に対して外筒を差速回転させる前半部の濃縮ゾーンと、スクリュー軸の回転トルクが増加した時に、外筒を回転させる後半部のろ過・脱水ゾーンに分割すると共に、ろ過・脱水ゾーンの後端に外筒ケーシングと内筒ケーシングを接続して調整室を形成し、密閉状の調整ゾーンとしたもので、濃縮ゾーンの外筒の差速回転によりスクリーンの目詰りが未然に防止され、濃度が低く水負荷が大きい汚泥でも、目詰まりすることなく多量のろ液が排出できる。そして、ろ過・脱水ゾーンの外筒を濃縮ゾーンの外筒と供回りさせて、固着せんとするケーキを剥離させる方向にせん断力を作用させて、過剰に滞留したケーキを軽減できる。更に、ろ過・脱水ゾーンから送り出されたケーキは、スクリュー羽根の表裏面の水分のバラツキを密閉状の調整ゾーンで含水率を均一にすることができる。
【０００７】
スクリュープレスの駆動手段が、濃縮ゾーンの外筒に正逆転可能な外筒駆動機と、スクリュー軸にスクリュー駆動機を連動連結して、差速回転させるものである。そして、スクリュープレスの濃縮・脱水運転は、濃縮ゾーンの外筒を、スクリュー軸の逆方向に回転させて、ろ過運転を行なうもので、スクリュー軸の回転速度に対する濃縮ゾーンの外筒の相対回転速度が速くなり、ろ過・脱水ゾーンへの押込み圧を高めることができる。濃縮ゾーンの外筒スクリーン面にスクリュー羽根の摺接回数が増加して、固形物負荷よりも水負荷が大きい汚泥でも、目詰りを未然に防止した外筒からろ液が分離される。濃度の高い濃縮汚泥がろ過・脱水ゾーンへ移送され、汚泥の処理量が増加する。
【０００８】
外筒の差速回転の手段が、外筒の中間軸受に係脱装置を配設し、外筒駆動機を逆転させて濃縮ゾーンの外筒をスクリュー軸と同方向に回転させる時に、濃縮ゾーンの外筒とろ過・脱水ゾーンの外筒を供回りさせるもので、異物の噛込みやケーキが充満して脱水が不能状態となったろ過・脱水部の外筒を逆回転させ、ケーキを逆送させて接触面の回転抵抗を軽減させることができる。そして、中間軸受を濃縮ゾーン側の軸継手とろ過・脱水ゾーン側の軸継手で構成し、この軸継手のどちらか一方に係止部と摺接部を有する伸縮自在なピストン爪と、他方の軸継手にストッパーをピストン爪の回動軌跡に対設したもので、濃縮ゾーンの外筒の正転時には、ピストン爪の摺接部をストッパーに摺接させてピストン爪を収縮させ、濃縮ゾーンの外筒の逆転時には、ピストン爪の係止部をストッパーに係止させて供回りさせるものである。
【０００９】
ろ過・脱水ゾーンの外筒の後端外周部に連結した回転板を、フレームに設けた回転板軸受で支架すると共に、回転板に外筒回転ロック用のストッパーと外筒位置検知用のストライカーを配設し、このストッパーとストライカーの回動軌跡に対設して、伸縮自在なエアーシリンダーの作動杆とエアーシリンダーに連動連結した位置検知用のリミットスイッチをフレームに配設して、スクリュー軸の回転トルクが増加した時に、作動杆をエアーシリンダーで後退させれば、ろ過・脱水ゾーンの外筒の固定が解除され、濃縮ゾーンの外筒とろ過・脱水ゾーンの外筒を供回りさせることができる。スクリュープレスの運転時には、位置検知用のリミットスイッチにて検知して、作動杆を前進させてストッパーに係止させ、圧密されたケーキでろ過・脱水ゾーンの外筒がスクリュー軸に連れ回りするのを防止できる。
【００１０】
ろ過・脱水ゾーンの外筒とスクリュー軸の後端部に、外筒ケーシングと内筒ケーシングをそれぞれ連結して、密閉状の調整室を形成して、この調整室を調整ゾーンとすると共に、外筒ケーシングの後端の排出口に背圧調整用のプレッサーを配設したもので、調整ゾーンからろ過・脱水ゾーンに背圧を加えて、固液分離を促進させ、円筒ケーシング内部のケーキに背圧を加えて水分を均一化させることができる。また、ろ過・脱水ゾーンの後端部に、フレームに連結した外筒ケーシングと、ろ過・脱水ゾーンのスクリュー軸に連結した内筒ケーシングとで密閉状の調整室を形成して、この調整室を調整ゾーンとすると共に、外筒ケーシングの後部下端に開口した排出口にフラップ弁を配設し、排出口の上方の内筒ケーシングにパドル羽根を止着してもよく、フラップ弁で背圧を加えながら、ケーキの水分を均一化させ、圧密されたケーキをパドル羽根で掻き取ってフラップ弁から排出させてもよいものである。
【００１１】
濃縮ゾーンとろ過・脱水ゾーンの外筒のスクリーン面に沿って洗浄管を配設し、濃縮ゾーンとろ過・脱水ゾーンの洗浄管の間に開閉弁を介装したもので、
ろ過・脱水ゾーンに過剰にケーキが滞留して内圧が異常に高くなった時には、ろ過・脱水ゾーンの外筒を濃縮ゾーンの外筒に供回りさせながら洗浄水を噴射すれば、洗浄水によりケーキとスクリーンの接触面を潤滑化させて、外筒のスクリーン面の再生と付き回りが解消できる。スクリュープレスへの汚泥の供給は、スクリュー軸に汚泥の供給路を設け、供給路の供給孔を濃縮ゾーンのろ過室の始端部に開口したもので、汚泥の供給孔がスクリュー軸に形成されているため、汚泥はスクリュー羽根の回転の影響を受けることなく供給され、凝集剤によって凝集した軟弱なフロックが破壊されることがなく、脱水性が損なわれることがない。
【００１２】
【発明の実施の形態】
この発明は上記のように構成してあり、濃縮ゾーンの外筒とスクリュー軸を互いに逆方向に回転させながら、下水等の有機性汚泥に高分子凝集剤を添加して、凝集させた汚泥をスクリュープレスに圧入する。始端側のスクリュー軸の供給路から、濃縮ゾーンのスクリュー羽根の間に供給された汚泥中の軟弱なフロックは、スクリュー羽根の回転の影響を受けて破壊されることなく、外筒内に流入する。スクリュープレスの濃縮、脱水操作は、ケーキの圧入初期には、調整ゾーンの排出口を閉止して、ろ過室の汚泥が充満常態となってから、排出口の開度を調節し、運転に移行する。濃縮ゾーンに供給された汚泥は外筒のスクリーンからろ液を排出し、逆方向の差速回転により濃縮圧密度を高めながら移送される。
【００１３】
逆回転による外筒のスクリーン面へのスクリュー羽根の摺接回数が増加して、スクリーンの目詰りをスクリュー羽根で未然に防止しながらスクリュー羽根がスクリーン面に堆積してくるケーキ層を掻取って移送させるので、濃度が低く水負荷の大きい汚泥でも濃縮できる。そして、回転しているろ過濃縮ゾーンの外筒に向って洗浄水を連続的に、あるいは、適宜間歇的に洗浄水を噴射して、スクリーン面の目詰まりを継続して防止させるので、濃縮ゾーンからろ過・脱水ゾーンに供給される濃縮汚泥の濃縮率が向上し、ろ過・脱水ゾーンへの濃縮汚泥の供給量が増加する。更に、ろ過・脱水ゾーンへの供給を濃縮ゾーンの逆転差速の押込み圧により向上する。
【００１４】
次に、濃縮された汚泥はろ過・脱水ゾーンの外筒に移送され、スクリュー羽根の羽根面で加圧されながら、さらにろ液を外筒のスクリーン面から排出し、圧密状となったスラリーはスクリュー羽根の圧搾力とテーパー状のスクリュー軸から発生する圧縮力、さらには、調整ゾーンの排出口での自由排出を抑制されたケーキによってろ過・脱水が促進される。ろ過・脱水ゾーンのケーキが充満してスクリュー軸の回転トルクが増加したときには、ろ過・脱水ゾーンの外筒を濃縮ゾーンの外筒に係止して、濃縮ゾーンの外筒をスクリュー軸の回転方向に逆回転させれば、外筒のスクリーンに固着せんとするケーキを剥離させ、充満固化したケーキを緩めて軟化することができる。ろ過・脱水ゾーンの外筒を回転させながら、スクリーンとケーキの摺接面に洗浄水を噴射すれば、摺接面を潤滑すると同時にケーキを湿潤させて逆送を容易とし、スクリーンの目詰まりを解消する。一定時間経過後に外筒の供回りを解除すれば、スクリュー軸を所定方向に回転させて濃縮・脱水運転を再開することができる。
【００１５】
この時、濃縮ゾーンに汚泥を供給していても、汚泥の供給部では濃度が低く、ろ液は外筒のスクリーンから取出され、短時間では固形分の容積が増加することがない。したがって、ろ過性が悪くなっているろ過・脱水ゾーンのろ過室の内圧を高めることがないもので、連続運転を行ないながら、スクリーンを再生することもできる。調整ゾーンからろ過・脱水ゾーンに背圧を加えて、固液分離を促進させ、ろ過・脱水ゾーンからスクリュー羽根で押出されたケーキは調整室に押出される。開口量を調節する調整室の排出口からケーキに背圧を加えられ、含水率のバラツキが均一化される。排出口から均質化されたケーキが排出される。
【００１６】
【実施例】
この発明の実施例を図面に基づき詳述すると、先ず、図１はスクリュープレスの一部縦断側面図であって、スクリュープレス１が前後のフレーム２、３に支架されており、スクリーンを周部に張設した円筒状の外筒４の内部に、スクリュー羽根５を巻き掛けたスクリュー軸６が配設してある。スクリュー軸６は汚泥の供給側からケーキの排出側に向って拡大させてあり、外筒４とスクリュー軸６との間のろ過室７を供給側から脱水側に向って減少させてある。なお、スクリュー軸６に巻き掛けたスクリュー羽根５の先端部に濃縮ゾーンの始端部からろ過・脱水ゾーンの終端部に渡って、ゴム等の弾力性を有する一連のスクレーパーを配設してもよい。
【００１７】
図２はスクリュープレスの供給側の拡大図であって、外筒４の供給側にフランジ８が連結してあり、フランジ８がフレーム２に設けた回転板軸受９に軸支してある。このフランジ８にスプロケット１０が嵌着してあり、フレーム２の架台１１に載置した正逆転可能な外筒駆動機１２のスプロケット１３にチエーン１４掛けしてある。外筒４に内設したスクリュー軸６の始端部に汚泥の供給管１５が連結してあり、この供給管１５に嵌着した軸受１６を外筒４に連結したフランジ８で回動自在に軸支してある。スクリュー軸６に供給管１５に接続する汚泥の供給路１７が設けてあり、濃縮ゾーンＡの始端側のろ過室７に供給孔１７ａが開口してある。汚泥の供給孔１７ａがスクリュー軸６に形成されているため、汚泥がスクリュー羽根５の回転の影響を受けることなく供給され、凝集剤によって凝集した軟弱なフロックが破壊されることがなく、脱水性が損なわれることがない。
【００１８】
図３はスクリュープレスの排出側の拡大図であって、外筒４に連結した回転板１８がフレーム３に配設した回転板軸受１９に軸支してある。外筒４に内設したスクリュー軸６の後端部にスクリー駆動軸２０が連結してある。図１に示すように、スクリー駆動軸２０はフレーム３の架台２１に設けた軸受２２に軸支してある。このスクリー駆動軸２０にスプロケット２３が嵌着してあり、フレーム３の架台２４に載置したスクリュー駆動機２５のスプロケット２６にチエーン２７掛けしてある。外筒４に内設したスクリュー軸６をスクリュー駆動機２５で回転させて、スクリュー羽根５でろ過室７内の汚泥を供給側からケーキの排出側に向って移送させながら、外筒４のスクリーンからろ液を排出する。
【００１９】
図１に示すように、円筒状の外筒４が前半部の濃縮ゾーンＡの外筒４ａと後半部のろ過・脱水ゾーンＢの外筒４ｂに分割されており、濃縮ゾーンＡの外筒４ａとろ過・脱水ゾーンＢの外筒４ｂの間に中間軸受２８が介装してある。図４は外筒の中間軸受であって、中間軸受２８は濃縮ゾーンＡ側の外筒４ａに連結した軸継手２８ａと、ろ過・脱水ゾーンＢ側の外筒４ｂに連結した軸継手２８ｂで構成してあり、外筒駆動機１２に連動連結した濃縮ゾーンＡ側の外筒４ａが、ろ過・脱水ゾーンＢ側の外筒４ｂと切離して回転できるようにしてある。スクリュープレス１の運転は、スクリュー軸６をスクリュー駆動機２５で回転させながら、濃縮ゾーンＡの外筒４ａを外筒駆動機１２でスクリュー軸６の反対方向に逆回転させて汚泥の濃縮、脱水を行なうようにしてある。逆方向に差速回転させることにより、スクリュー軸６の回転速度に対する濃縮ゾーンＡの外筒４ａの相対回転速度が速くなり、ろ過・脱水ゾーンＢへの押込み圧を高めることができる。固形物負荷よりも水負荷が大きい汚泥でも、濃縮ゾーンＡの外筒４ａのスクリーン面にスクリュー羽根５の摺接回数が増加して、目詰りを未然に防止した外筒４ａからろ液が分離され、濃度の高い濃縮汚泥がろ過・脱水ゾーンＢへ移送され、汚泥の処理量が増加する。
【００２０】
図４に示すように、中間軸受２８に濃縮ゾーンＡの外筒４ａとろ過・脱水ゾーンＢの外筒４ｂを供回りさせる係脱装置２９が配設してある。この係脱装置２９は、濃縮ゾーンＡ側の軸継手２８ａにストッパー３０が止着してあり、ストッパー３０の先端は垂設面の係止部３０ａと湾曲面の摺接部３０ｂが設けてある。ろ過・脱水ゾーンＢ側の軸継手２８ｂに伸縮自在なピストン爪３１を配設したハウジング３２が止着してあり、図５に示すように、ピストン爪３１の先端は垂設面の係止部３１ａと傾斜面の摺接部３１ｂが設けてある。常態においては、内蔵したスプリング３３でピストン爪３１を伸長させてあり、伸長させたピストン爪３１の回動軌跡に対設して、濃縮ゾーンＡ側の軸継手２８ａのストッパー３０が設けてある。スクリュープレス１のろ過・脱水時には、ピストン爪３１の回動軌跡に対設してあるストッパー３０がピストン爪３１の傾斜面の摺接部３１ｂに摺接してスプリング３３を圧縮して、ピストン爪３１をハウジング３０の内部に後退させる。濃縮ゾーンＡの外筒４ａとろ過・脱水ゾーンＢの外筒４ｂの供回りを解除して、濃縮ゾーンＡの外筒４ａだけをスクリュー軸６の逆方向に回転させる。濃縮ゾーンＡの外筒４ａの相対回転速度をスクリュー軸６の回転速度よりも早くして、濃縮ゾーンＡでのスクリュー軸６の外筒４ａのスクリーン面への摺接回数を多くして、外筒４ａの目詰まりを防止する。
【００２１】
ろ過・脱水ゾーンＢに過剰にケーキが滞留して内圧が異常に高くなった時には、外筒駆動機１２を逆回転させて、スクリュー軸６の回転と同方向に濃縮ゾーンＡの外筒４ａを回転させると、ストッパー３０がピストン爪３１の垂設面の係止部３１ａに係合される。ろ過・脱水ゾーンＢの外筒４ｂが濃縮ゾーンＡの外筒４ａに係止されて供回りして、ろ過・脱水ゾーンＢの外筒４ｂをスクリュー軸６と同方向に回転させる。異物の噛込みやろ過・脱水部にケーキが充満して脱水が不能状態となったろ過・脱水ゾーンＢの外筒４ｂを逆回転させ、固着せんとするケーキを剥離させる方向にケーキを逆送させてせん断力を作用させる。
【００２２】
外筒４の周面に沿って洗浄管３４が配設してあり、回転しているろ過濃縮ゾーンＡの外筒４ａに向って洗浄水を連続的に、あるいは、適宜間歇的に洗浄水を噴射して、外筒４ａのスクリーン面の目詰まりを継続して防止させる。目詰りを未然に防止した外筒４ａからろ液が分離され、濃度の高い濃縮汚泥がろ過・脱水ゾーンＢへ移送できる。濃縮ゾーンＡとろ過・脱水ゾーンＢの間の洗浄管３４に開閉弁３５が介装してあり、ろ過・脱水ゾーンＢの外筒４ｂを濃縮ゾーンＡの外筒４ａと供回りさせて、ろ過・脱水ゾーンＢの過剰なケーキの滞留を解消する時に、洗浄管３４の開閉弁３５を解放すれば、洗浄水によりケーキとろ過・脱水ゾーンＢの外筒４ｂの接触面を潤滑化させる。外筒４ｂのスクリーン面の再生と、ろ過・脱水ゾーンＢの外筒４ｂとケーキとの接触面の回転抵抗を軽減させる。濃縮ゾーンＡとろ過・脱水ゾーンＢの間に開閉弁３５を設けることにより、不必要な洗浄水の消費が軽減できる。
【００２３】
図６はろ過・脱水ゾーンの外筒のスクリュー軸との供回り防止装置であって、ろ過・脱水ゾーンＢの外筒４ｂの後端に連結した回転板１８の外周面に、外筒回転ロック用のストッパー３６と外筒位置検知用のストライカー３７が配設してある。このストッパー３６とストライカー３７の回動軌跡に、フレーム３に配設した伸縮自在なエアーシリンダー３８の作動杆３９とエアーシリンダー３８に連動連結した位置検知用のリミットスイッチ４０が対設してある。
濃縮ゾーンＡの外筒４ａを逆回転させて、ろ過・脱水ゾーンＢの外筒４ｂを供回りさせる時には、公知の手段により、エアーシリンダー３８の作動杆３９を後退させてストッパー３６の係合を解除する。ろ過・脱水ゾーンＢの外筒４ｂをスクリュー軸６の回転方向に回転させて、外筒４ｂのスクリーン面に固着せんとするケーキを剥離させ、充満固化したケーキを緩めて軟化させる。過剰に滞留するケーキを排除と外筒４ｂのスクリーン面の再生が終った時には、回転してきたストライカー３７を位置検知用のリミットスイッチ４０に当接させて、その検知信号によりエアーシリンダー３８の作動杆３９を伸長させる。作動杆３９をストッパー３６に係合させて、充満するケーキの摩擦抵抗によるろ過・脱水ゾーンＢの外筒４ｂとスクリュー軸６との供回りを防止する。
【００２４】
図３に示すように、ろ過・脱水ゾーンＢの外筒４ｂとスクリュー軸６の後端に、外筒ケーシング４１と内筒ケーシング４２がそれぞれ連結してあり、外筒ケーシング４１は円筒板で構成して、内筒ケーシング４２はスクリュー駆動軸２０に支架してある。外筒ケーシング４１と内筒ケーシング４２とで密閉状の調整室４３を形成して、この調整室４３を調整ゾーンＣとしてある。ろ過・脱水ゾーンＢからスクリュー羽根５で調整室４３に押出されたケーキは調整室４３の内部で圧密されて含水率のバラツキを均一化させる。調整ゾーンＣの外筒ケーシング４１の排出口４４に背圧調整用のプレッサー４５が配設してあり、プレッサー４５はフレーム３に配設したプレッサー移動軸４６に移動自在に支架してある。プレッサー４５はフレーム３に配設したシリンダー４７で移動させ、排出口４４の開口量を調節しながら調整室４３のケーキに背圧を加えて水分を均一化させ、更に、調整ゾーンＣからろ過・脱水ゾーンＢの外筒４ｂ内に背圧を加えて、固液分離を促進させて水分を調整する。
【００２５】
図７はスクリュープレスに設けた調整ゾーンの他の実施例であって、ろ過・脱水ゾーンＢの後端部に、フレーム３に連結した外筒ケーシング４８と、ろ過・脱水ゾーンＢのスクリュー軸６に連結した内筒ケーシング４９とで密閉状の調整室５０を形成して、この調整室５０を調整ゾーンＣ’としてある。調整室５０の後端が閉塞されて外筒ケーシング４８の下端に排出口５１が開口してある。この排出口５１にフラップ弁５２が開閉自在としてあり、図８及び図９に示すように、フラップ弁５２に連結したリンク５３がエアーシリンダー５４に枢着してあり、開口度を調節して調整ゾーンＣ’のケーキに背圧を加え、水分を均一化させる。更に、ろ過・脱水ゾーンＢのケーキに背圧を加え、固液分離を促進させ含水率を低下させる。排出口の上部の内筒ケーシング４９にパドル羽根５５が止着してあり、ろ過・脱水ゾーンＢのスクリュー羽根５で移送される圧密状のケーキを削り取り、排出口のフラップ弁の開口度を調整しながら排出させる。なお、符号５６はろ液トラフである。
【００２６】
【表１】

【００２７】
【表２】

【００２８】
外筒を前後に分割して後段に調整ゾーンを配設した、スクリーン口径がφ２００ｍｍの本願発明のスクリュープレスと、洗浄時に外筒を回転させる、スクリーン口径がφ２００ｍｍの従来のスクリュープレスを対比して実験を行なった。表１及び表２は、混合生汚泥と消化汚泥を対象としたスクリュープレスの処理性能の実験データーであって、縦軸に処理量ＫｇＤＳ／ｈ、横軸にケーキ水分％ＷＢを表している。本願発明のスクリュープレスは従来のスクリュープレスと比較して、ケーキ水分は、混合生汚泥で３％、消化汚泥では２％ケーキの含水率が低下した。そして、処理量は、混合生汚泥で５０％増加し、消化汚泥では３０％増加した。
含水率の低下の理由は、
▲１▼濃縮ゾーンの外筒の逆差速回転により、スクリュー軸の相対回転速度が速くなり、スクリーンの目詰りが未然に防止された。
▲２▼逆方向の差速回転により濃縮圧密度を高めながら、ろ過・脱水ゾーンへの押込み圧を高めることができた。
▲３▼調整ゾーンの排出口での自由排出を抑制されたケーキによってろ過・脱水ゾーンに背圧が加えられ、固液分離を促進させ、円筒ケーシング内部のケーキに背圧を加えて水分を均一化させた。
ことに起因するものと予測される。
また、処理量の増加の理由は、
▲１▼逆方向の差速回転により濃縮圧密度を高めながら、ろ過・脱水ゾーンへの押込み圧を高めた。
▲２▼ろ過・脱水部の外筒を逆回転させ、ケーキを逆送させて接触面の回転抵抗を軽減させた。
▲３▼ろ過・脱水部の外筒を逆回転させ、充満したケーキを逆送させて接触面の回転抵抗を軽減させた。
ことに起因するものと予測される。
【００２９】
【発明の効果】
この発明は上記のように構成してあり、濃縮ゾーンのスクリュー羽根の回転数が相対的に高められ、スクリーンのろ過面を再生して分離するろ液量を増加させ、ろ過・脱水ゾーンへの移送汚泥の濃度が高められる。濃縮ゾーンの逆転差速の押込み圧によりろ過・脱水ゾーンへの供給が向上して、調整ゾーンで脱水ケーキを均質化させるスクリュープレスとなるものである。
即ち、従来の外筒回転型のスクリュープレスは、凝集フロックの破損や多量の洗浄水を必要として、脱水ケーキの含水率にバラツキがあったものであるが、この発明にあっては、スクリュー軸に対して外筒を差速回転させる前半部の濃縮ゾーンと、スクリュー軸の回転トルクが増加した時に、外筒を回転させる後半部のろ過・脱水ゾーンに分割すると共に、ろ過・脱水ゾーンの後端に調整室を形成し、密閉状の調整ゾーンとしたもので、濃縮ゾーンの外筒の差速回転によりスクリーンの目詰りが未然に防止され、水負荷が大きい汚泥でもろ液が大量に排出できる。濃度の高い濃縮汚泥がろ過・脱水ゾーンへ移送され、汚泥の処理量が増加する。そして、ろ過・脱水ゾーンの外筒を濃縮ゾーンの外筒と供回りさせれば、外筒のスクリーンに固着せんとするケーキを剥離させ、充満固化したケーキを緩めて軟化することができる。更に、調整ゾーンで背圧を掛けて、圧密状にケーキの含水率を均一にすることができる。
【００３０】
スクリュープレスの駆動手段が、濃縮ゾーンの外筒に正逆転可能な外筒駆動機と、スクリュー軸にスクリュー駆動機を連動連結して、濃縮ゾーンの外筒を、スクリュー軸の逆方向に回転させるもので、濃縮ゾーンのスクリュー軸の相対回転速度が速くなり、濃縮ゾーンの外筒のスクリーン面にスクリュー羽根の摺接回数が増加する。逆方向の差速回転により濃縮圧密度を高めながら、ろ過・脱水ゾーンへの押込み圧を高めることができる。
【００３１】
外筒の中間軸受を濃縮ゾーン側の軸継手とろ過・脱水ゾーン側の軸継手で構成し、この軸継手のどちらか一方に伸縮自在なピストン爪と、他方の軸継手にストッパーを回動軌跡に対設し、濃縮ゾーンの外筒を逆転させる時に、濃縮ゾーンの外筒とろ過・脱水ゾーンの外筒を供回りさせるもので、異物の噛込みやケーキが充満して脱水が不能状態となったろ過・脱水部の外筒を逆回転させ、ケーキを逆送させて接触面の回転抵抗を軽減させることができる。
【００３２】
ろ過・脱水ゾーンの外筒の後端外周部に連結した回転板に外筒回転ロック用のストッパーと外筒位置検知用のストライカーを配設し、このストッパーとストライカーの回動軌跡に対設して、伸縮自在なエアーシリンダーの作動杆とエアーシリンダーに連動連結した位置検知用のリミットスイッチをフレームに配設したもので、スクリュー軸の回転トルクが増加した時に、ろ過・脱水ゾーンの外筒の固定を解除して、スクリュープレスの運転時に、ろ過・脱水ゾーンの外筒を固定して、ろ過・脱水ゾーンの外筒がスクリュー軸に連れ回りするのを防止させるものである。
【００３３】
ろ過・脱水ゾーンの外筒とスクリュー軸の後端部に調整ゾーンとした密閉状の調整室を形成して、外筒ケーシングの後端の排出口に背圧調整用のプレッサーを配設したもので、さらには、調整ゾーンの排出口での自由排出を抑制されたケーキによってろ過・脱水ゾーンに背圧が加えられ、固液分離を促進させ、円筒ケーシング内部のケーキに背圧を加えて水分を均一化させることができる。また、調整ゾーンにパドル羽根を配設して排出口にフラップ弁を設けてもよく、フラップ弁で背圧を加えながら、ケーキの水分を均一化させ、圧密されたケーキをパドル羽根で掻き取って排出させてもよいものである。
【００３４】
外筒に沿って洗浄管を配設し、濃縮ゾーンとろ過・脱水ゾーンの洗浄管の間に開閉弁を介装したもので、回転しているろ過濃縮ゾーンの外筒のスクリーン面の目詰まりを継続して防止させるので、濃縮ゾーンからろ過・脱水ゾーンに供給される濃縮汚泥の濃縮率が向上し、ろ過・脱水ゾーンへの濃縮汚泥の供給量が増加する。そして、ろ過・脱水ゾーンにケーキが滞留して内圧が異常に高くなった時には、ろ過・脱水ゾーンの外筒を濃縮ゾーンの外筒に供回りさせながら洗浄水を噴射すれば、洗浄水によりケーキとスクリーンの接触面を潤滑化させて、外筒のスクリーン面の再生と付き回りが解消できる。開閉弁を介装することにより、不必要な洗浄水の消費が軽減できる。スクリュー軸に設けた汚泥の供給路を濃縮ゾーンのろ過室の始端部に開口したもので、汚泥中の軟弱な凝集フロックがスクリュー羽根の影響を受けることなく供給されて、脱水性が損なわれることがない。
【図面の簡単な説明】
【図１】この発明に係るフイルタープレスの縦断側面図である。
【図２】同じく、スクリュープレスの供給側の拡大図である。
【図３】同じく、スクリュープレスの調整ゾーンの拡大図である。
【図４】同じく、濃縮ゾーンとろ過・脱水装置の間に設けた外筒の中間軸受の平面図である。
【図５】同じく、外筒の中間軸受に設けた係脱装置の概念図である。
【図６】同じく、ろ過・脱水ゾーンの外筒のスクリュー軸との供回り防止装置の正面図である。
【図７】同じく、スクリュープレスの調整ゾーンの、他の実施例の拡大図である。
【図８】同じく、スクリュープレスの調整ゾーン排出口の縦断正面図である。
【図９】同じく、スクリュープレスの調整ゾーン排出口の側面図である。
【符号の説明】
３フレーム
４、４ａ、４ｂ外筒
５スクリュー羽根
６スクリュー軸
７ろ過室
１２外筒駆動機
１７供給路
１７ａ供給孔
１８回転板
１９回転板軸受
２５スクリュー駆動機
２８中間軸受
２８ａ，２８ｂ軸継手
２９係脱装置
３０、３６ストッパー
３１ピストン爪
３１ａ係止部
３１ｂ摺接部
３４洗浄管
３５開閉弁
３７ストライカー
３８エアーシリンダー
３９作動杆
４０リミットスイッチ
４１、４８外筒ケーシング
４２、４９内筒ケーシング
４３、５０調整室
４４、５１排出口
４５プレッサー
５２フラップ弁
５５パドル羽根
Ａ濃縮ゾーン
Ｂろ過・脱水ゾーン
Ｃ、Ｃ’ 調整ゾーン[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a screw press that is divided into a concentration zone and a filtration / dehydration zone and in which an outer cylinder and a screw shaft are rotatably arranged. Specifically, even in sludge having a low water concentration greater than a solid load, The present invention relates to an improvement of a screw press that makes it possible to concentrate and dewater while preventing clogging and to make the water content of the dewatered cake uniform.
[0002]
[Prior art]
Conventionally, organic sludge such as sewage, human waste, or food production processing wastewater has added a polymer flocculant to generate floc. Organic sludge having a low concentration is concentrated by a centrifugal concentrator or a flotation concentrator and filtered and dehydrated. In these concentrators, for example, 1% of sludge is concentrated to 4 to 5%, and this concentrated sludge is filtered and dehydrated with a screw press. All of these apparatuses have a large installation area, and the driving power cost and the cost of the polymer flocculant are high, and the maintenance is troublesome. When organic sludge with low concentration is directly concentrated and dehydrated with a screw press, the sludge concentration is low on the sludge injection side of the screw press, so the outer cylinder screen in the concentration zone has a larger water load than the solid load, and the outer cylinder screen. It is necessary to discharge a large amount of water. In particular, a polymer thin film is generated by the polymer flocculant, and in the concentration zone, residues are attached to the screen of the outer cylinder and clogging is likely to occur.
[0003]
As a conventional outer cylinder rotary type screw press, the filtration cylinder is divided into the sludge injection side and the discharge side at the middle part, the pitch interval of the screw blades on the sludge injection side is narrowed, and the sludge injection side filtration cylinder is transferred While rotating at a speed slower than the rotation speed of the screw, filtering and dewatering the sludge supplied from the hopper, high pressure fluid is sprayed from the outside of the cylinder, and the cake layer adhering to the micropores of this cylinder is washed and filtered A screw press that continuously maintains the dehydration effect is known, for example, as described in Japanese Patent Publication No. 3-78123. In addition, while rotating a rotating screw wrapped with screw blades with a narrow pitch interval toward the outlet side in the opposite direction to the screen drum, sludge and the like are supplied from the shaft portion of the rotating screw to the screen drum, and a large amount of moisture is supplied. An apparatus for separation is also known as described in, for example, Japanese Patent Application Laid-Open No. 2000-33495.
[0004]
[Problems to be solved by the invention]
In the screw press that forcibly rotates the filtration cylinder on the sludge injection side, the screw blades can increase the number of sliding contact of the filtration cylinder and regenerate the screen surface, and continuously wash while rotating the outer cylinder. By spraying water, an effect of preventing clogging of the screen can be obtained. However, clogging of the filtration cylinder on the discharge side makes it difficult to regenerate the screen surface with only washing water. In addition, a lot of washing water is required for continuous washing. The flocs of flocculated sludge supplied from the hopper are fragile, and the broken fine particles are discharged from the screen together with the separation liquid, so that sufficient performance cannot be exhibited.
[0005]
Further, in a screw press in which the pitch interval on the cake discharge side of the screw blade is narrowed and aggregated sludge is supplied from the shaft center by a pump, the pressure density in the initial zone can be increased, and the screen drum is By rotating in the opposite direction to the rotating screw, it is possible to regenerate the outer cylinder screen of the concentration zone, but there is a risk that a soft cake will come out from the screen of the outer cylinder on the discharge side where the pitch interval is narrow, There was a drawback that clogging occurred early.
In the above conventional outer cylinder rotary type screw press, the moisture content of the dewatered cake discharged varies due to the moisture difference between the front and back cakes of the screw blades. After the dehydrated cake is composted or incinerated The processing was hindered. The present invention applies a conventional technique for performing filtration and dewatering while rotating the filtration cylinder on the sludge injection side of the screw press, and uses the sludge injection side of the filtration cylinder as a concentration zone to concentrate the polymer flocculant at a low concentration. A screw press that prevents clogging of the outer cylinder screen even with organic sludge, enables concentration, filtration and dehydration, and homogenizes the final dehydrated cake in the adjustment zone.
[0006]
[Means for Solving the Problems]
The gist of the present invention is that a screw shaft around which a screw blade is wound is disposed in an outer cylinder, the filtration chamber between the outer cylinder and the screw shaft is relatively reduced from the supply side toward the dehydration side, In the screw press that discharges the filtrate from the screen of the outer cylinder while rotating the screw shaft and removes the cake from the terminal end of the filtration chamber, the sludge supplied to the start end is provided with an intermediate bearing on the outer cylinder. The first half of the concentrating zone, which rotates the outer cylinder with respect to the screw shaft at a different speed, and the second half, the filtration / dehydration zone, which rotates the outer cylinder when the rotational torque of the screw shaft increases, are filtered and dehydrated. An adjustment chamber is formed by connecting an outer cylinder casing and an inner cylinder casing at the rear end of the zone to form a sealed adjustment zone, which prevents the screen from becoming clogged by the differential speed rotation of the outer cylinder in the concentration zone. The , Concentration at low water load is larger sludge, a large amount of the filtrate without clogging can be discharged. Then, the outer cylinder in the filtration / dehydration zone is rotated with the outer cylinder in the concentration zone, and the shearing force is applied in the direction in which the cake to be fixed is peeled off, so that excessively accumulated cake can be reduced. Furthermore, the cake sent out from the filtration / dehydration zone can make the moisture content uniform in the hermetic adjustment zone for the moisture variation on the front and back surfaces of the screw blades.
[0007]
The drive means of the screw press is an outer cylinder drive machine that can be rotated forward and backward to the outer cylinder of the concentration zone, and a screw drive machine that is linked to the screw shaft and rotated at a differential speed. The concentration / dehydration operation of the screw press is performed by rotating the outer cylinder of the concentration zone in the opposite direction of the screw shaft and performing the filtration operation. The relative rotational speed of the outer cylinder of the concentration zone with respect to the rotational speed of the screw shaft. Speeds up, and the pressure to push into the filtration / dehydration zone can be increased. The number of sliding contact of the screw blades on the outer cylinder screen surface of the concentration zone is increased, and the filtrate is separated from the outer cylinder in which clogging is prevented even with sludge having a water load larger than the solid load. Concentrated sludge with high concentration is transferred to the filtration / dehydration zone, and the amount of sludge treatment increases.
[0008]
When the means for differential speed rotation of the outer cylinder is provided with an engagement / disengagement device in the intermediate bearing of the outer cylinder, the outer cylinder driving machine is reversed to rotate the outer cylinder of the concentration zone in the same direction as the screw shaft. Rotating the outer cylinder of the filtration / dehydration zone and rotating the outer cylinder of the filtration / dehydration section that has become incapable of dewatering due to foreign matter biting or full cake, reverse the cake. The rotational resistance of the contact surface can be reduced by feeding. The intermediate bearing is composed of a concentrating zone-side shaft coupling and a filtration / dehydration zone-side shaft joint, and one of the shaft joints has a retractable piston claw having a locking portion and a sliding contact portion, and the other side. A stopper is provided on the shaft coupling on the rotation path of the piston claw. When the outer cylinder of the concentrating zone rotates forward, the sliding portion of the piston claw is brought into sliding contact with the stopper to contract the piston claw and At the time of reverse rotation of the outer cylinder, the locking portion of the piston claw is locked by the stopper and is rotated.
[0009]
A rotating plate connected to the outer periphery of the rear end of the outer cylinder of the filtration / dehydration zone is supported by a rotating plate bearing provided on the frame, and a stopper for rotating the outer cylinder and a striker for detecting the outer cylinder position are provided on the rotating plate. Installed in opposition to the rotation trajectory of this stopper and striker, the operating rod of the telescopic air cylinder and the limit switch for position detection linked to the air cylinder are installed on the frame, and the screw shaft If the operating rod is moved backward with an air cylinder when the rotational torque increases, the outer cylinder of the filtration / dehydration zone is released, and the outer cylinder of the concentration zone and the outer cylinder of the filtration / dehydration zone can be rotated. it can. When operating the screw press, the position detection limit switch detects it, the operating rod is moved forward and locked to the stopper, and the outer cylinder of the filtration / dehydration zone is rotated around the screw shaft with the compacted cake. Can be prevented.
[0010]
The outer cylinder casing and the inner cylinder casing are connected to the outer cylinder of the filtration / dehydration zone and the rear end portion of the screw shaft, respectively, to form a sealed adjustment chamber. A back pressure adjustment presser is installed at the rear end of the cylindrical casing, and back pressure is applied from the adjustment zone to the filtration / dehydration zone to promote solid-liquid separation. Water can be made uniform by applying pressure. In addition, a sealed adjustment chamber is formed at the rear end of the filtration / dehydration zone with an outer casing connected to the frame and an inner casing connected to the screw shaft of the filtration / dehydration zone. In addition to the adjustment zone, a flap valve may be installed at the discharge port opened at the lower rear end of the outer cylinder casing, and the paddle blade may be fixed to the inner cylinder casing above the discharge port. While adding, the moisture of the cake may be made uniform, and the compacted cake may be scraped off by paddle blades and discharged from the flap valve.
[0011]
A cleaning pipe is arranged along the screen surface of the outer cylinder of the concentration zone and the filtration / dehydration zone, and an open / close valve is interposed between the cleaning pipe of the concentration zone and the filtration / dehydration zone.
If the cake is excessively accumulated in the filtration / dehydration zone and the internal pressure becomes abnormally high, the washing water is sprayed while the outer cylinder of the filtration / dehydration zone is fed to the outer cylinder of the concentration zone. And the contact surface of the screen can be lubricated, and the screen surface of the outer cylinder can be prevented from being regenerated and attached. Sludge is supplied to the screw press by providing a sludge supply path on the screw shaft and opening a supply hole in the supply path at the beginning of the filtration chamber in the concentration zone. The sludge supply hole is formed on the screw shaft. Therefore, the sludge is supplied without being affected by the rotation of the screw blades, the soft flocs aggregated by the flocculant are not destroyed, and the dewaterability is not impaired.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is configured as described above. While rotating the outer cylinder of the concentration zone and the screw shaft in opposite directions, a polymer flocculant is added to organic sludge such as sewage to agglomerate sludge. Press fit into the screw press. The soft flocs in the sludge supplied between the screw blades in the concentration zone from the screw shaft supply path on the start end side flow into the outer cylinder without being damaged by the rotation of the screw blades. . Concentration and dehydration operations of the screw press are closed at the initial stage of press-fitting of the cake, and after the sludge in the filtration chamber is filled normally, the opening of the outlet is adjusted and the operation is started. To do. The sludge supplied to the concentration zone discharges the filtrate from the screen of the outer cylinder, and is transferred while increasing the concentration pressure density by the reverse differential speed rotation.
[0013]
The number of times the screw blades slide against the screen surface of the outer cylinder due to reverse rotation increases, and the screw blade scrapes off the cake layer that accumulates on the screen surface while preventing the screen from clogging with the screw blades. Because it is transported, even sludge with low concentration and high water load can be concentrated. Then, the cleaning water is sprayed continuously or appropriately intermittently toward the outer cylinder of the rotating filtration concentration zone to prevent clogging of the screen surface. The concentration rate of the concentrated sludge supplied to the filtration / dehydration zone is improved, and the supply amount of the concentrated sludge to the filtration / dehydration zone increases. Furthermore, the supply to the filtration / dehydration zone is improved by the reverse pressure difference indentation pressure in the concentration zone.
[0014]
Next, the concentrated sludge is transferred to the outer cylinder of the filtration / dehydration zone, and while being pressurized by the blade surfaces of the screw blades, the filtrate is further discharged from the screen surface of the outer cylinder, Filtration and dehydration are promoted by the pressing force of the screw blades, the compressive force generated from the tapered screw shaft, and the cake with suppressed free discharge at the discharge port of the adjustment zone. When the rotational torque of the screw shaft increases due to the cake of the filtration / dehydration zone filling up, the outer cylinder of the filtration / dehydration zone is locked to the outer cylinder of the concentration zone, and the outer cylinder of the concentration zone is rotated in the direction of rotation of the screw shaft. If the cake is rotated in the reverse direction, the cake that sticks to the screen of the outer cylinder is peeled off, and the cake that has been solidified can be loosened and softened. If cleaning water is sprayed onto the sliding surface of the screen and cake while rotating the outer cylinder of the filtration / dehydration zone, the sliding surface is lubricated and the cake is moistened at the same time, facilitating reverse feed, and clogging the screen. Eliminate. If the rotation of the outer cylinder is canceled after a lapse of a certain time, the concentration / dehydration operation can be resumed by rotating the screw shaft in a predetermined direction.
[0015]
At this time, even if sludge is supplied to the concentration zone, the concentration is low in the sludge supply section, and the filtrate is taken out from the screen of the outer cylinder, so that the volume of solid content does not increase in a short time. Therefore, the internal pressure of the filtration chamber in the filtration / dehydration zone having poor filterability is not increased, and the screen can be regenerated while performing continuous operation. Back pressure is applied from the adjustment zone to the filtration / dehydration zone to promote solid-liquid separation, and the cake extruded from the filtration / dehydration zone with screw blades is extruded into the adjustment chamber. Back pressure is applied to the cake from the outlet of the adjustment chamber that adjusts the amount of opening, and the variation in moisture content is made uniform. The homogenized cake is discharged from the outlet.
[0016]
【Example】
An embodiment of the present invention will be described in detail with reference to the drawings. First, FIG. 1 is a partially longitudinal side view of a screw press, in which the screw press 1 is supported on the front and

rear frames

2 and 3, A screw shaft 6 around which a screw blade 5 is wound is disposed inside a cylindrical outer tube 4 stretched on the surface. The screw shaft 6 is enlarged from the sludge supply side toward the cake discharge side, and the filtration chamber 7 between the outer cylinder 4 and the screw shaft 6 is decreased from the supply side toward the dewatering side. A series of scrapers having elasticity such as rubber may be provided at the tip of the screw blade 5 wound around the screw shaft 6 from the start end of the concentration zone to the end of the filtration / dehydration zone. .
[0017]
FIG. 2 is an enlarged view of the supply side of the screw press. A flange 8 is connected to the supply side of the outer cylinder 4, and the flange 8 is pivotally supported on a rotary plate bearing 9 provided on the frame 2. A sprocket 10 is fitted to the flange 8, and a chain 14 is hung on a sprocket 13 of an outer cylinder driving machine 12 that can be rotated forward and backward and is placed on a frame 11 of the frame 2. A sludge supply pipe 15 is connected to a start end portion of a screw shaft 6 provided in the outer cylinder 4, and a bearing 16 fitted to the supply pipe 15 is pivoted by a flange 8 connected to the outer cylinder 4. It is supported. A sludge supply path 17 connected to the supply pipe 15 is provided in the screw shaft 6, and a supply hole 17 a is opened in the filtration chamber 7 on the start end side of the concentration zone A. Since the sludge supply hole 17a is formed in the screw shaft 6, the sludge is supplied without being affected by the rotation of the screw blade 5, and the soft flocs aggregated by the flocculant are not destroyed, and the dehydrating property is eliminated. Will not be damaged.
[0018]
FIG. 3 is an enlarged view of the discharge side of the screw press, and a rotating plate 18 connected to the outer cylinder 4 is pivotally supported on a rotating plate bearing 19 disposed on the frame 3. A scree drive shaft 20 is connected to a rear end portion of the screw shaft 6 provided in the outer cylinder 4. As shown in FIG. 1, the scree drive shaft 20 is pivotally supported by a bearing 22 provided on a frame 21 of the frame 3. A sprocket 23 is fitted on the screen drive shaft 20, and a chain 27 is hung on a sprocket 26 of a screw drive 25 mounted on a frame 24 of the frame 3. The screw shaft 6 provided in the outer cylinder 4 is rotated by a screw driver 25, and the sludge in the filtration chamber 7 is transferred from the supply side toward the cake discharge side by the screw blades 5 while the screen of the outer cylinder 4 is moved. Drain the filtrate.
[0019]
As shown in FIG. 1, the cylindrical outer cylinder 4 is divided into an outer cylinder 4a in the first half of the concentration zone A and an outer cylinder 4b in the second half of the filtration / dehydration zone B. An intermediate bearing 28 is interposed between the outer cylinder 4 b of the filtration / dehydration zone B. FIG. 4 shows an intermediate bearing of an outer cylinder. The intermediate bearing 28 is composed of a shaft coupling 28a connected to the outer cylinder 4a on the concentration zone A side and a shaft coupling 28b connected to the outer cylinder 4b on the filtration / dehydration zone B side. The outer cylinder 4a on the concentration zone A side linked to the outer cylinder driving machine 12 can be rotated separately from the outer cylinder 4b on the filtration / dehydration zone B side. The screw press 1 is operated by rotating the screw shaft 6 with the screw drive 25 and rotating the outer cylinder 4a of the concentration zone A in the opposite direction to the screw shaft 6 with the outer cylinder drive 12 to concentrate and dewater sludge. It is intended to do. By rotating in the reverse direction at a differential speed, the relative rotational speed of the outer cylinder 4a of the concentration zone A with respect to the rotational speed of the screw shaft 6 is increased, and the indentation pressure into the filtration / dehydration zone B can be increased. Even with sludge having a larger water load than the solid load, the number of sliding contact of the screw blades 5 on the screen surface of the outer cylinder 4a in the concentration zone A is increased, and the filtrate is separated from the outer cylinder 4a that prevents clogging in advance. The concentrated sludge having a high concentration is transferred to the filtration / dehydration zone B, and the amount of sludge treated increases.
[0020]
As shown in FIG. 4, an engagement / disengagement device 29 that rotates the outer cylinder 4 a of the concentration zone A and the outer cylinder 4 b of the filtration / dehydration zone B to the intermediate bearing 28 is provided. In this engagement / disengagement device 29, a stopper 30 is fixed to a shaft coupling 28a on the concentration zone A side, and a stopper 30a on a hanging surface and a sliding contact portion 30b on a curved surface are provided at the tip of the stopper 30. . A housing 32 provided with a retractable piston claw 31 is fixed to the shaft coupling 28b on the filtration / dehydration zone B side, and as shown in FIG. 31a and the sliding contact part 31b of an inclined surface are provided. In a normal state, the piston claw 31 is extended by a built-in spring 33, and a stopper 30 of the shaft coupling 28a on the concentration zone A side is provided opposite to the rotation trajectory of the extended piston claw 31. At the time of filtration and dehydration of the screw press 1, the stopper 30 provided on the rotation trajectory of the piston claw 31 slides on the sliding contact portion 31b of the inclined surface of the piston claw 31, compresses the spring 33, and the piston claw 31 Is retracted into the housing 30. The rotation of the outer cylinder 4 a in the concentration zone A and the outer cylinder 4 b in the filtration / dehydration zone B is released, and only the outer cylinder 4 a in the concentration zone A is rotated in the reverse direction of the screw shaft 6. The relative rotation speed of the outer cylinder 4a in the concentration zone A is made faster than the rotation speed of the screw shaft 6, and the number of times of sliding contact of the screw cylinder 6 with the screen of the outer cylinder 4a in the concentration zone A is increased. Clogging of the cylinder 4a is prevented.
[0021]
When the cake is excessively accumulated in the filtration / dehydration zone B and the internal pressure becomes abnormally high, the outer cylinder driving machine 12 is rotated in the reverse direction so that the outer cylinder 4a in the concentration zone A is moved in the same direction as the rotation of the screw shaft 6. When rotated, the stopper 30 is engaged with the engaging portion 31 a of the suspended surface of the piston claw 31. The outer cylinder 4b of the filtration / dehydration zone B is engaged with the outer cylinder 4a of the concentration zone A and is rotated to rotate the outer cylinder 4b of the filtration / dehydration zone B in the same direction as the screw shaft 6. Reverse rotation of the outer cylinder 4b of the filtration / dehydration zone B where the cake is filled with foreign matter and the filtration / dehydration part is filled with the cake and the dehydration cannot be performed is reversed. To apply a shearing force.
[0022]
A cleaning pipe 34 is disposed along the outer peripheral surface of the outer cylinder 4, and the cleaning water is continuously or appropriately intermittently supplied to the outer cylinder 4a of the rotating filtration concentration zone A. The spray is continuously prevented from clogging the screen surface of the outer cylinder 4a. The filtrate is separated from the outer cylinder 4 a that prevents clogging, and concentrated sludge having a high concentration can be transferred to the filtration / dehydration zone B. An on-off valve 35 is interposed in the cleaning pipe 34 between the concentration zone A and the filtration / dehydration zone B, and the outer cylinder 4b in the filtration / dehydration zone B is rotated with the outer cylinder 4a in the concentration zone A for filtration. If the on-off valve 35 of the cleaning pipe 34 is released when the excessive cake stays in the dewatering zone B is eliminated, the contact surface between the cake and the outer cylinder 4b of the filtration / dewatering zone B is lubricated by the cleaning water. The regeneration of the screen surface of the outer cylinder 4b and the rotational resistance of the contact surface between the outer cylinder 4b and the cake in the filtration / dehydration zone B are reduced. By providing the on-off valve 35 between the concentration zone A and the filtration / dehydration zone B, unnecessary consumption of washing water can be reduced.
[0023]
FIG. 6 is a device for preventing rotation with the screw shaft of the outer cylinder of the filtration / dehydration zone, and the outer cylinder rotation lock is provided on the outer peripheral surface of the rotating plate 18 connected to the rear end of the outer cylinder 4b of the filtration / dehydration zone B. A stopper 36 and a striker 37 for detecting the outer cylinder position are provided. On the trajectory of the stopper 36 and the striker 37, an operating rod 39 of a telescopic air cylinder 38 disposed on the frame 3 and a limit switch 40 for position detection linked to the air cylinder 38 are provided.
When the outer cylinder 4a in the concentration zone A is reversely rotated and the outer cylinder 4b in the filtration / dehydration zone B is rotated, the operating rod 39 of the air cylinder 38 is moved backward by a known means to engage the stopper 36. To release. The outer cylinder 4b of the filtration / dehydration zone B is rotated in the direction of rotation of the screw shaft 6 to peel off the cake that is fixed to the screen surface of the outer cylinder 4b, and the cake that has been solidified is loosened and softened. When the excessively accumulated cake is removed and the screen surface of the outer cylinder 4b is regenerated, the rotating striker 37 is brought into contact with the position detection limit switch 40, and the operation signal of the air cylinder 38 is detected by the detection signal. 39 is extended. The operating rod 39 is engaged with the stopper 36 to prevent the outer cylinder 4b in the filtration / dehydration zone B and the screw shaft 6 from rotating due to the frictional resistance of the cake to be filled.
[0024]
As shown in FIG. 3, an outer cylinder casing 41 and an inner cylinder casing 42 are connected to the outer cylinder 4b of the filtration / dehydration zone B and the rear end of the screw shaft 6, respectively, and the outer cylinder casing 41 is constituted by a cylindrical plate. The inner cylinder casing 42 is supported on the screw drive shaft 20. The outer cylinder casing 41 and the inner cylinder casing 42 form a sealed adjustment chamber 43, and this adjustment chamber 43 is used as an adjustment zone C. The cake extruded from the filtration / dehydration zone B to the adjusting chamber 43 by the screw blades 5 is consolidated inside the adjusting chamber 43 to make the variation in moisture content uniform. A presser 45 for adjusting the back pressure is disposed at the discharge port 44 of the outer casing 41 in the adjustment zone C, and the presser 45 is movably supported on a presser moving shaft 46 disposed on the frame 3. The presser 45 is moved by a cylinder 47 arranged in the frame 3, and the back pressure is applied to the cake in the adjustment chamber 43 while adjusting the opening amount of the discharge port 44 to make moisture uniform. A back pressure is applied to the outer cylinder 4b in the dehydration zone B to promote solid-liquid separation and adjust moisture.
[0025]
FIG. 7 shows another embodiment of the adjustment zone provided in the screw press. At the rear end of the filtration / dehydration zone B, an outer casing 48 connected to the frame 3 and the screw shaft 6 of the filtration / dehydration zone B are shown. A sealed adjustment chamber 50 is formed by the inner cylinder casing 49 connected to the adjustment chamber C, and this adjustment chamber 50 is defined as an adjustment zone C ′. The rear end of the adjustment chamber 50 is closed, and a discharge port 51 is opened at the lower end of the outer casing 48. A flap valve 52 can be freely opened and closed at the discharge port 51. As shown in FIGS. 8 and 9, a link 53 connected to the flap valve 52 is pivotally attached to an air cylinder 54, and is adjusted by adjusting the opening degree. Back pressure is applied to the cake in zone C ′ to make the moisture uniform. Furthermore, back pressure is applied to the cake in the filtration / dehydration zone B to promote solid-liquid separation and reduce the water content. The paddle blade 55 is fixed to the inner casing 49 at the upper part of the discharge port, and the compact cake transferred by the screw blade 5 in the filtration / dehydration zone B is scraped off to adjust the opening degree of the flap valve of the discharge port. While discharging. Reference numeral 56 denotes a filtrate trough.
[0026]
[Table 1]

[0027]
[Table 2]

[0028]
Contrast the screw press of the present invention with a screen diameter of φ200 mm, which has an outer cylinder divided into front and rear and an adjustment zone in the rear stage, and a conventional screw press with a screen diameter of φ200 mm that rotates the outer cylinder during cleaning. The experiment was conducted. Tables 1 and 2 are experimental data on the processing performance of the screw press for mixed raw sludge and digested sludge, where the vertical axis represents the treatment amount KgDS / h and the horizontal axis represents the cake moisture% WB. In the screw press of the present invention, the moisture content of the cake moisture was 3% in the mixed raw sludge and 2% in the digested sludge as compared with the conventional screw press. And the processing amount increased by 50% with mixed raw sludge and increased by 30% with digested sludge.
The reason for the decrease in moisture content is
(1) Due to the reverse differential speed rotation of the outer cylinder in the concentration zone, the relative rotation speed of the screw shaft was increased, and the screen was prevented from being clogged.
(2) The indentation pressure into the filtration / dehydration zone could be increased while increasing the concentration density by reverse speed rotation in the reverse direction.
(3) Back pressure is applied to the filtration / dehydration zone by the cake whose free discharge at the outlet of the adjustment zone is suppressed, promoting solid-liquid separation, and applying back pressure to the cake inside the cylindrical casing to make moisture uniform Made it.
This is expected to be caused by this.
The reason for the increase in throughput is
(1) The indentation pressure into the filtration / dehydration zone was increased while increasing the concentration density by reverse speed differential rotation.
(2) The outer cylinder of the filtration / dehydration section was reversely rotated, and the cake was reversely fed to reduce the rotational resistance of the contact surface.
(3) The outer cylinder of the filtration / dehydration section was rotated in the reverse direction, and the filled cake was fed back to reduce the rotational resistance of the contact surface.
This is expected to be caused by this.
[0029]
【The invention's effect】
The present invention is configured as described above, the rotational speed of the screw blades in the concentration zone is relatively increased, the amount of filtrate to be separated is increased by regenerating the filtration surface of the screen, and the filtration / dehydration zone is supplied. Concentration of transported sludge is increased. The supply pressure to the filtration / dehydration zone is improved by the indentation pressure at the reverse differential speed in the concentration zone, and the screw press is made to homogenize the dewatered cake in the adjustment zone.
In other words, the conventional outer cylinder rotary type screw press requires breakage of the flocs flocs and a large amount of washing water, and the moisture content of the dewatered cake varies. Is divided into a first-half concentration zone that rotates the outer cylinder at a different speed and a second-stage filtration / dehydration zone that rotates the outer cylinder when the rotational torque of the screw shaft increases. An adjustment chamber is formed at the end to form a sealed adjustment zone, which prevents the clogging of the screen by the differential speed rotation of the outer cylinder of the concentration zone, and discharges a large amount of filtrate even in sludge with a large water load. it can. Concentrated sludge with high concentration is transferred to the filtration / dehydration zone, and the amount of sludge treatment increases. Then, if the outer cylinder of the filtration / dehydration zone is rotated with the outer cylinder of the concentration zone, the cake that is fixed to the screen of the outer cylinder can be peeled, and the cake that has been solidified can be loosened and softened. Furthermore, it is possible to make the moisture content of the cake uniform in a compacted state by applying a back pressure in the adjustment zone.
[0030]
The drive means of the screw press is linked to the outer cylinder drive that can be rotated forward and backward to the outer cylinder of the concentration zone, and the screw drive is linked to the screw shaft to rotate the outer cylinder of the concentration zone in the opposite direction of the screw shaft. Therefore, the relative rotational speed of the screw shaft in the concentration zone increases, and the number of times the screw blade slides on the screen surface of the outer cylinder in the concentration zone increases. While increasing the concentration density by reverse speed rotation in the reverse direction, it is possible to increase the indentation pressure into the filtration / dehydration zone.
[0031]
The intermediate bearing of the outer cylinder is composed of a concentrator zone shaft joint and a filtration / dehydration zone shaft joint. A telescopic piston claw is provided on one of the shaft joints, and a stopper is pivoted on the other shaft joint. When reversing the outer cylinder of the concentrating zone, the outer cylinder of the concentrating zone and the outer cylinder of the filtration / dehydration zone are rotated. By rotating the outer cylinder of the filtration / dehydration section that has become reverse, the cake is fed back to reduce the rotational resistance of the contact surface.
[0032]
A stopper for rotating the outer cylinder and a striker for detecting the position of the outer cylinder are arranged on the rotating plate connected to the outer periphery of the rear end of the outer cylinder of the filtration / dehydration zone, and this stopper and the striker are placed opposite to each other. A telescopic air cylinder operating rod and a position detection limit switch linked to the air cylinder are installed on the frame. When the rotational torque of the screw shaft increases, the outer cylinder of the filtration / dehydration zone When the screw press is operated, the outer cylinder of the filtration / dehydration zone is fixed to prevent the outer cylinder of the filtration / dehydration zone from rotating around the screw shaft.
[0033]
A sealed adjustment chamber is formed as an adjustment zone at the rear end of the filtration / dehydration zone and the screw shaft, and a back pressure adjustment presser is provided at the outlet of the rear end of the outer casing. Furthermore, back pressure is applied to the filtration / dehydration zone by the cake whose free discharge at the outlet of the adjustment zone is suppressed, promoting solid-liquid separation, and applying back pressure to the cake inside the cylindrical casing to Can be made uniform. A paddle blade may be provided in the adjustment zone and a flap valve may be provided at the discharge port. While applying back pressure with the flap valve, the moisture of the cake is made uniform, and the compacted cake is scraped off with the paddle blade. Can be discharged.
[0034]
A cleaning pipe is installed along the outer cylinder, and an open / close valve is interposed between the cleaning pipe in the concentration zone and the filtration / dehydration zone. The screen surface of the outer cylinder in the rotating filtration concentration zone is clogged. Therefore, the concentration rate of the concentrated sludge supplied from the concentration zone to the filtration / dehydration zone is improved, and the supply amount of the concentrated sludge to the filtration / dehydration zone is increased. When the cake stays in the filtration / dehydration zone and the internal pressure becomes abnormally high, if the washing water is sprayed while the outer cylinder of the filtration / dehydration zone is fed to the outer cylinder of the concentration zone, the cake is washed with the washing water. And the contact surface of the screen can be lubricated, and the screen surface of the outer cylinder can be prevented from being regenerated and attached. By using the on-off valve, unnecessary consumption of washing water can be reduced. The sludge supply path on the screw shaft is opened at the beginning of the filtration chamber of the concentration zone, and the soft flocculent floc in the sludge is supplied without being affected by the screw blades, and the dewaterability is impaired. There is no.
[Brief description of the drawings]
FIG. 1 is a longitudinal side view of a filter press according to the present invention.
FIG. 2 is an enlarged view of the supply side of the screw press in the same manner.
FIG. 3 is also an enlarged view of an adjustment zone of a screw press.
FIG. 4 is also a plan view of an intermediate bearing of an outer cylinder provided between a concentration zone and a filtration / dehydration device.
FIG. 5 is a conceptual view of an engaging / disengaging device provided in the intermediate bearing of the outer cylinder.
FIG. 6 is a front view of the rotation preventing device with the screw shaft of the outer cylinder of the filtration / dehydration zone.
FIG. 7 is also an enlarged view of another embodiment of the adjustment zone of the screw press.
FIG. 8 is a longitudinal sectional front view of the adjustment zone discharge port of the screw press.
FIG. 9 is a side view of the adjustment zone discharge port of the screw press.
[Explanation of symbols]
3 frames
4, 4a, 4b outer cylinder
5 Screw blade
6 Screw shaft
7 Filtration chamber
12 outer cylinder drive
17 Supply path
17a Supply hole
18 Rotating plate
19 Rotating plate bearing
25 Screw drive
28 Intermediate bearing
28a, 28b Shaft coupling
29 Disengagement device
30, 36 stopper
31 Piston claw
31a Locking part
31b Sliding part
34 Washing tube
35 On-off valve
37 Striker
38 Air cylinder
39 Actuation
40 limit switch
41, 48 Outer casing
42, 49 Inner cylinder casing
43, 50 Adjustment room
44, 51 outlet
45 presser
52 flap valve
55 paddle feather
A Concentration zone
B Filtration / Dehydration Zone
C, C 'adjustment zone

Claims

The screw shaft (6) around which the screw blade (5) is wound is disposed on the outer cylinder (4), and the filtration chamber (7) between the outer cylinder (4) and the screw shaft (6) is connected to the dehydration side from the supply side. The sludge supplied to the start end of the filtration chamber (7) is discharged from the screen of the outer cylinder (4) while rotating the screw shaft (6). 7) In the screw press for taking out the cake from the terminal end of 7), the first half in which the intermediate bearing (28) is arranged in the outer cylinder (4) and the outer cylinder (4a) is rotated at a differential speed with respect to the screw shaft (6). When the rotational torque of the screw zone (A) and the screw shaft (6) increases, the outer cylinder (4b) is rotated into the latter half of the filtration / dehydration zone (B) and the filtration / dehydration zone A rotating plate (18) connected to the outer periphery of the rear end of the outer cylinder (4b) of (B), The rotary plate bearing (19) provided in the ram (3) is supported, and the rotary plate (18) is provided with a stopper (36) for locking the outer cylinder rotation and a striker (37) for detecting the outer cylinder position, A limit switch for position detection that is interlocked with the operating rod (39) of the telescopic air cylinder (38) and the air cylinder (38) in opposition to the rotation trajectory of the stopper (36) and the striker (37). (40) is arranged on the frame (3), and the outer casing (41, 48) and the inner casing (42, 49) are connected to the rear end of the filtration / dehydration zone (B) to adjust the chamber (43, A screw press having a concentrating function, characterized in that 50) is formed and a sealed adjustment zone (C, C ′) is formed.

The outer cylinder drive (12) capable of rotating forward and backward is connected to the outer cylinder (4a) of the concentration zone (A), and the screw drive (25) is linked to the screw shaft (6). A screw press having the concentration function described in 1.

The screw press having a concentration function according to claim 1 or 2, wherein the outer cylinder (4a) of the concentration zone (A) is rotated in a direction opposite to the screw shaft (6) to perform a filtration operation. .

An engagement / disengagement device (29) is disposed on the intermediate bearing (28) of the outer cylinder (4a, 4b), the outer cylinder driving machine (12) is reversed, and the outer cylinder (4a) of the concentration zone (A) is screwed. The outer cylinder (4a) of the concentration zone (A) and the outer cylinder (4b) of the filtration / dehydration zone (B) are rotated when rotating in the same direction as the shaft (6). A screw press having the concentration function according to any one of 3.

The intermediate bearing (28) is composed of a shaft coupling (28a) on the concentration zone (A) side and a shaft coupling (28b) on the filtration / dehydration zone side B, and is engaged with either of the shaft couplings (28a, 28b). A retractable piston claw (31) having a stop (31a) and a sliding contact part (31b), and a stopper (30) on the other shaft joint (28a, 28b) are placed against the rotation trajectory of the piston claw (31). The screw press having a concentration function according to claim 4, wherein the screw press is provided.

An outer cylinder casing (41) and an inner cylinder casing (42) are connected to the rear end portions of the outer cylinder (4b) and the screw shaft (6) of the filtration / dehydration zone (B), respectively. (43) is formed, and the adjustment chamber (43) is used as an adjustment zone (C), and a back pressure adjusting presser (45) is provided at the discharge port (44) at the rear end of the outer casing (41). The screw press having a concentration function according to any one of claims 1 to 5 , wherein the screw press is provided.

An outer casing (48) connected to the frame (3) and an inner casing (49) connected to the screw shaft (6) of the filtration / dehydration zone (B) at the rear end of the filtration / dehydration zone (B). ) To form a sealed adjustment chamber (50), which is used as an adjustment zone (C ') and a discharge port (51) opened at the lower end of the rear portion of the outer casing (48). flap valve (52) is disposed, above the inner cylinder casing (49) to any one of claims 1 to 5 paddle blades (55), characterized in that the fastening of the outlet (51) A screw press having the concentration function described in 1.

A cleaning pipe (34) is arranged along the screen surface of the outer cylinder (4a, 4b) of the concentration zone (A) and the filtration / dehydration zone (B), and the concentration zone (A) and the filtration / dehydration zone (B) A screw press having a concentrating function according to any one of claims 1 to 7 , wherein an open / close valve (35) is interposed between the cleaning pipes (34).

The screw shaft (6) is provided with a sludge supply path (17), and the supply hole (17a) of the supply path (17) is opened at the beginning of the filtration chamber (7) of the concentration zone (A). The screw press which has a concentration function of any one of Claims 1 thru | or 8 .