JP3748798B2

JP3748798B2 - centrifuge

Info

Publication number: JP3748798B2
Application number: JP2001299778A
Authority: JP
Inventors: 孝治藤本; 純大橋
Original assignee: Tomoe Engineering Co Ltd
Current assignee: Tomoe Engineering Co Ltd
Priority date: 2001-09-28
Filing date: 2001-09-28
Publication date: 2006-02-22
Anticipated expiration: 2021-09-28
Also published as: JP2003103200A

Description

【０００１】
【発明の属する技術分野】
本発明は、ボウル内に供給された原液から沈降物と浮遊物それに母液を分離するための遠心分離機に関する。このような遠心分離機は、廃プラスチックのリサイクルの分野において、ＰＶＣ（塩ビ）やＰＥ（ポリエチレン）等の破砕された各種樹脂の比重差を利用した遠心分離および脱液に用いられるものである。
【０００２】
【従来の技術】
従来、この種のデカンタ型の遠心分離機は、例えば、図７に示すようなものが知られている。これはボウル１内で原液が遠心力により沈降粒子と母液とに分けられ、沈降粒子は、ボウル１と微少の回転差を与えられているスクリューコンベヤ２により搬送されて、図７中のボウル１の図中で右端より脱液排出されるように構成されている。
【０００３】
ところが、前記遠心分離機は、沈降粒子の分離と洗浄および脱液に関しては様々な工夫がなされたものが知られているが、原液中に含まれる浮遊粒子に関しては、何ら対策が施されていないものが多い。従って、原液からの浮遊粒子の分離自体が困難であり、沈降粒子と分離された液体中に混入した浮遊粒子の分離は、例えば、バスケット型の遠心分離機や他の固液分離機を利用する工程が別途必要であった。
【０００４】
このような不都合を解消するために、例えば、特開平６−１７８９４８号公報に記載された湿式分離装置等が提案されている。かかる装置は、ボウルの軸心を通る１本のシャフト上に互いに逆向きに巻かれた２つのスクリューを有し、一方のスクリューにより沈降粒子を回転容器の一端側へ搬送し、他方の逆巻きのスクリューにより浮遊粒子を回転容器の他端側へ搬送するものである。
【０００５】
【発明が解決しようとする課題】
前述したような公報記載の湿式分離装置では、沈降粒子搬送用スクリューがボウルの略中央から他端側には存在しないため、浮遊粒子搬送用スクリューまたは処理液の動きによって沈降粒子搬送用スクリューより他端側に沈降粒子が一旦移動すれば、かかる沈降粒子はボウル内面に蓄積してしまって、装置の運転中に装置外に排出することができず、定期的に装置を止めて分解した上で除去する必要があった。
【０００６】
また、前記湿式分離装置では、母液排出口が沈降粒子の排出側に配置されている関係上、浮遊粒子をスクリューにより回転容器の他端側へ搬送する際、母液の流れは浮遊粒子の搬送方向とは逆向きとなり、浮遊粒子の搬送効率の低下が容易に予想される。浮遊粒子の搬送効率が低下すれば、沈降及び浮遊粒子の比重分離精度も当然低下することになる。
【０００７】
本発明は、以上のような従来技術が有する問題点に着目してなされたもので、装置全体の大型化を招くことなく、原液から沈降物と浮遊物とそれに母液を確実かつ効率よく分離することができ、しかもそれぞれ分離した物を効率良く脱液することができる遠心分離機を提供することを目的としている。
【０００８】
【課題を解決するための手段】
前述した目的を達成するための本発明の要旨とするところは、次の各項の発明に存する。
［１］ボウル（２０）内に供給された原液から沈降物と浮遊物それに母液を分離するための遠心分離機（１０）であって、回転する筒状の前記ボウル（２０）に内挿されてボウル（２０）と同軸で異なる速度で回転するスクリューコンベヤ（４０）を有し、該スクリューコンベヤ（４０）は、その軸胴部（４１）の途中よりフライトの螺旋巻き方向が両端に向かって互いに逆向きに設けられ、一方のフライトは沈降物を搬送する沈降物用フライト（４２ａ）となり、他方のフライトは浮遊物を搬送する浮遊物用フライト（４２ｂ）となる遠心分離機（１０）において、
前記ボウル（２０）は、その両端側に内径が漸次縮小するテーパー部（２１ａ，２１ｂ）を有し、一方のテーパー部（２１ａ）の先に沈降物排出口（２２ａ）があり、他方のテーパー部（２１ｂ）の先に浮遊物排出口（２２ｂ）があり、他方のテーパー部（２１ｂ）壁面とその区間のボウル（２０）内壁とで囲まれた区画室（２４１，２７１）に、ボウル（２０）半径方向の液深を規制すると共に浮遊物を取り除いた母液をボウル（２０）外へ排出可能なダム部（２５，２６２）を設け、
前記ボウル（２０）の他方のテーパー部（２１ｂ）は、その壁面に多数の孔乃至スリット（２３）を有し内周側が濾材（３０）で覆われており、
前記ダム部（２５）は、前記区画室（２４１）内を臨むボウル（２０）内壁に、周方向に複数配設したスキミングチューブから成り、各スキミングチューブの突出した先端口で規制されるダム設定液面は、前記他方のテーパー部（２１ｂ）の傾斜途中までを覆う位置に設定され、
前記ボウル（２０）内に原液を供給する手段は、前記スクリューコンベヤ（４０）の軸胴部（４１）内にフィードチューブ（１５）を挿通させて、該フィードチューブ（１５）の出口に連通する原液供給口（４４）を前記軸胴部（４１）の略中央に開設して成り、
前記沈降物用フライト（４２ａ）は、前記他方のテーパー部（２１ｂ）の始端付近から前記沈降物排出口（２２ａ）にかけて前記一方のテーパー部（２１ａ）を含む前記ボール（２０）内壁に先端が沿うよう設けられ、
前記浮遊物用フライト（４２ｂ）は、前記他方のテーパー部（２１ｂ）の内周面上における前記ダム設定液面の境界よりやや前記原液供給口（４４）寄りの位置から前記浮遊物排出口（２２ｂ）にかけて前記他方のテーパー部（２１ｂ）を含む前記ボール（２０）内壁に先端が沿うよう設けられ、
前記沈降物用フライト（４２ａ）の始端側に、浮遊物を母液と共に前記浮遊物排出口（２２ｂ）側へ積極的に搬送させるための加速用パドル（４３）を連設し、該加速用パドル（４３）の終端側を、前記浮遊物用フライト（４２ｂ）の始端側に対してボウル（２０）軸方向に僅かに重なる位置まで延出させることを特徴とする遠心分離機（１０）。
【００１２】
［２］ボウル（２０）内に供給された原液から沈降物と浮遊物それに母液を分離するための遠心分離機（１０）であって、回転する筒状の前記ボウル（２０）に内挿されてボウル（２０）と同軸で異なる速度で回転するスクリューコンベヤ（４０）を有し、該スクリューコンベヤ（４０）は、その軸胴部（４１）の途中よりフライトの螺旋巻き方向が両端に向かって互いに逆向きに設けられ、一方のフライトは沈降物を搬送する沈降物用フライト（４２ａ）となり、他方のフライトは浮遊物を搬送する浮遊物用フライト（４２ｂ）となる遠心分離機（１０）において、
前記ボウル（２０）は、その両端側に内径が漸次縮小するテーパー部（２１ａ，２１ｂ）を有し、一方のテーパー部（２１ａ）の先に沈降物排出口（２２ａ）があり、他方のテーパー部（２１ｂ）の先に浮遊物排出口（２２ｂ）があり、他方のテーパー部（２１ｂ）壁面とその区間のボウル（２０）内壁とで囲まれた区画室（２４１，２７１）に、ボウル（２０）半径方向の液深を規制すると共に浮遊物を取り除いた母液をボウル（２０）外へ排出可能なダム部（２５，２６２）を設け、
前記ボウル（２０）の他方のテーパー部（２６）は、その内径が漸次縮小する１段目テーパー部（２６１）と、該１段目テーパー部（２６１）の終端最小内径と略同一内径で続く中間円筒部（２６２）と、該中間円筒部（２６２）の終端よりさらに内径が漸次縮小する２段目テーパー部（２６３）とに区分けされた多段状に設けられ、前記中間円筒部（２６２）は、その壁面に多数の孔乃至スリット（２３）を有し内周側が濾材（３０）で覆われており、
前記中間円筒部（２６２）がそのまま前記ダム部を成し、該中間円筒部（２６２）の内周面がダム設定液面と略一致し、前記他方のテーパー部（２６）のうち少なくとも前記中間円筒部（２６２）の壁面で囲まれた前記区画室（２７１）内を臨むボウル（２０）内壁に、母液の排出口（２８）を複数開設したことを特徴とする遠心分離機（１０）。
【００１３】
［３］前記ボウル（２０）内に原液を供給する手段は、前記スクリューコンベヤ（４０）の軸胴部（４１）内にフィードチューブ（１５）を挿通させて、該フィードチューブ（１５）の出口に連通する原液供給口（４４）を前記軸胴部（４１）の略中央に開設して成り、
前記沈降物用フライト（４２ａ）は、前記他方のテーパー部（２６）における前記１段目テーパー部（２６１）の始端付近から前記沈降物排出口（２２ａ）にかけて設けられ、
前記浮遊物用フライト（４２ｂ）は、前記１段目テーパー部（２６１）の終端最小内径部位よりやや前記原液供給口（４４）寄りの位置から前記浮遊物排出口（２２ｂ）にかけて設けられたことを特徴とする［２］記載の遠心分離機（１０）。
【００１４】
［４］前記沈降物用フライト（４２ａ）の始端側に、浮遊物を母液と共に前記浮遊物排出口（２２ｂ）側へ積極的に搬送させるための加速用パドル（４３）を連設し、該加速用パドル（４３）の終端側を、前記浮遊物用フライト（４２ｂ）の始端側に対してボウル（２０）軸方向に僅かに重なるように、前記中間円筒部（２６２）の始端よりも僅かに前記２段目テーパー部（２６３）寄りの位置まで延出させることを特徴とする［３］記載の遠心分離機（１０）。
【００１５】
次に本発明の作用を説明する。
本発明に係る遠心分離機（１０）によれば、スクリューコンベヤ（４０）の軸胴部（４１）内を挿通するフィードチューブ（１５）を介して、軸胴部（４１）に開設された原液供給口（４４）よりボウル（２０）内に供給された原液中の沈降物は、ボウル（２０）の内壁に沿うように沈降し、ボウル（２０）と微少差速で回転するスクリューコンベヤ（４０）の沈降物用フライト（４２ａ）により一方のテーパー部（２１ａ）へ搬送される。ここで沈降物は、予めダム部（２５）で設定されている液深よりも内径側へテーパー部（２１ａ）上を移動する際に脱液されて、沈降物排出口（２２ａ）より外部へ排出される。
【００１６】
また、原液中の浮遊物は、前記沈降物排出口（２２ａ）の反対側となる他方のテーパー部（２１ｂ）に向かって母液と共に、他方のテーパー部（２１ｂ）の始端付近まで配されている前記沈降物用フライト（４２ａ）の巻きピッチ間を螺旋状に流れる。ここで母液は、他方のテーパー部（２１ｂ）でその内周側を覆う濾材（３０）の隙間および壁面にある多数の孔乃至スリット（２３）を通り抜け、テーパー部（２１ｂ）の壁面で囲まれた区画室（２４１）内を臨むボウル（２０）内壁に複数配設されたスキミングチューブより外部へ分離排出される。
【００１７】
浮遊物は、前記沈降物用フライト（４２ａ）の始端側に連続して繋がり、他方のテーパー部（２１ｂ）の始端付近からテーパー部（２１ｂ）内周面上におけるダム設定液境界よりやや浮遊物排出口（２２ｂ）側寄りの区間まで延出した加速用パドル（４３）によって、母液と共に他方のテーパー部（２１ｂ）に積極的に搬送される。
【００１８】
さらに浮遊物は、前記加速用パドル（４３）の終端側と僅かにオーバーラップさせたテーパー部（２１ｂ）内周面上のダム設定液面境界よりやや原液供給口（４４）寄りの位置から浮遊物排出口（２２ｂ）までの区間に配された浮遊物用フライト（４２ｂ）によって、前述した沈降物とは逆方向に搬送され、予めダム部（２５）で設定されている液深よりも内径側へテーパー部（２１ｂ）上を移動する際に濾過脱液されて、浮遊物排出口（２２ｂ）より外部へ排出される。
【００１９】
また、別の発明に係る遠心分離機（１０）によれば、ボウル（２０）内に供給された原液中の沈降物は、ボウル（２０）の内壁に沿うように沈降し、ボウル（２０）と微少差速で回転するスクリューコンベヤの沈降物用フライト（４２ａ）により一方のテーパー部（２６）へ搬送される。ここで沈降物は、予めダム部すなわち他方にある多段状のテーパー部（２６）の中間円筒部（２６２）で設定されている液深よりも内径側へ一方のテーパー部（２１ａ）上を移動する際に脱液されて、沈降物排出口（２２ａ）より外部へ排出される。
【００２０】
原液中の浮遊物は、前記沈降物排出口（２２ａ）の反対側となる他方の多段状のテーパー部（２６）に向かって母液と共に、多段状テーパー部（２６）の１段目テーパー部（２６１）の始端付近まで配されている前記沈降物用フライト（４２ａ）の巻きピッチ間を螺旋状に流れる。浮遊物は、前記沈降物用フライト（４２ａ）の始端側に連続して繋がり、１段目テーパー部（２６１）の始端付近から中間円筒部（２６２）の始端よりも僅かに２段目テーパー部（２６３）寄りの区間まで延出した加速用パドル（４３）によって、１段目テーパー部（２６１）から中間円筒部（２６２）へと母液と共に積極的に搬送される。
【００２１】
母液は中間円筒部（２６２）において、その内周側を覆う濾材（３０）の隙間および壁面にある多数の孔乃至スリット（２３）を通り抜け、少なくとも中間円筒部（２６２）の壁面で隔離された区画室（２７１）内のボウル（２０）内壁に複数開設された排出口（２８）より外部へ分離排出される。さらに浮遊物は、前記加速用パドル（４３）終端部と僅かにオーバーラップさせた１段目テーパー部（２６１）の最小内径終端よりやや原液供給口（４４）寄りの位置から浮遊物排出口（２２ｂ）までの区間に配された浮遊物用フライト（４２ｂ）によって、前述した沈降物とは逆方向に搬送され、２段目テーパー部（２６３）上を移動する際に濾過脱液されて、浮遊物排出口（２２ｂ）より外部へ排出される。
【００２２】
【発明の実施の形態】
以下、図面に基づき本発明を代表する各種の実施の形態を説明する。
図１〜図３は本発明の第１実施の形態を示している。
本実施の形態に係る遠心分離機１０は、デカンタ型遠心分離機と通称される装置と同様、図１に示すように、円筒型（筒状）のボウル２０内にスクリューコンベヤ４０を内挿し、これらを相対的に回転可能に支持して成り、前記ボウル２０内に供給される原液から沈降物と浮遊物それに母液を別々に分離することができるように構成されている。
【００２３】
図１に示すように、ボウル２０とその内部のスクリューコンベヤ４０は、ケーシング１１の内部にシャフト１２ａ，１２ｂを介して回転可能に軸支されている。ボウル２０およびスクリューコンベヤ４０は、片側の軸受け１３に連設されたギヤボックス１４によって微少差速で回転駆動される。かかる回転駆動機構は公知であり詳細な説明は省略する。
【００２４】
ボウル２０の一端側（図１で右側）は沈降物の排出方向となっており、かかる一端側には、その内径が漸次縮小するテーパー部２１ａが形成されている。テーパー部２１ａの先（終端側）には、沈降物排出口２２ａが円周方向に複数開設されている。また、ボウル２０の他端側（図１で左側）は浮遊物の排出方向となっており、かかる他端側にも、その内径が漸次縮小するテーパー部２１ｂが形成されている。テーパー部２１ｂの先（終端側）には、浮遊物排出口２２ｂが円周方向に複数開設されている。
【００２５】
一方のテーパー部２１ａは、ボウル２０自体の内周面が傾斜することで形成されているが、他方のテーパー部２１ｂは、ボウル２０自体の内周面が傾斜することなく、この内周面に後付けされてテーパーを成す内層壁材２４から成る。図２に示すように、他方のテーパー部２１ｂは、その壁面に多数の孔乃至スリット２３を有し内周側が濾材３０で覆われている。なお、内層壁材２４において実際にはテーパーを成さない円筒部分についても、図示したように多数の孔乃至スリット２３を設けると良い。
【００２６】
孔乃至スリット２３の径や幅は、浮遊物の粒子径をさほど考慮する必要はないが、濾材３０は、浮遊物の粒子径より小径サイズの多数の微小孔またはスリットを有する素材から成る。具体的には、従来より利用されている打ち抜き穴型スクリーン、ウェッジワイヤースクリーン等の他、多孔質セラミック成形体や、セグメント型スクリーン（分割ブロックスクリーン）等により形成するとよい。なお、テーパー部２１ｂの内周側は濾材３０の厚さ分だけ僅かに表面が削られている。
【００２７】
他方のテーパー部２１ｂの壁面とその区間のボウル２０内壁とで囲まれた区画室２４１には、ボウル２０半径方向の液深を規制すると共に浮遊物を取り除いた母液をボウル２０外へ排出可能なダム部２５が設けられている。ダム部２５は、区画室２４１内を臨むボウル２０内壁に、周方向に複数配設したスキミングチューブから成る。各スキミングチューブの突出した先端口２４１で規制されるダム設定液面は、テーパー部２１ｂの傾斜途中までを覆う位置に設定されている。
【００２８】
ここでダム部２５は、浮遊物排出口２２ｂの直ぐ手前にある他方のテーパー部２１ｂに重なる位置にあるので、ボウル２０内に供給された母液の流れと浮遊物の搬送方向が一致することになる。また、ダム部２５で規制されるボウル２０内の液深は、ダム部２５より母液が外部へ排出されている間は本来のダム設定液面を越えるので、テーパー部２１ｂの濾材３０が随時液中に没する状態が生じている。
【００２９】
スクリューコンベヤ４０は、その軸胴部４１の途中よりフライトの螺旋巻き方向が両端に向かって互いに逆向きに設けられ、一方のフライトは沈降物を搬送する沈降物用フライト４２ａとなり、他方のフライトは浮遊物を搬送する浮遊物用フライト４２ｂとなっている。また、軸胴部４１内にはフィードチューブ１５が挿通されており、該フィードチューブ１５の出口に連通する原液供給口４４が軸胴部４１の略中央に複数開設されている。
【００３０】
沈降物用フライト４２ａは、他方のテーパー部２１ｂの始端付近から前記沈降物排出口２２ａにかけて設けられている。また、浮遊物用フライト４２ｂは、他方のテーパー部２１ｂの内周面上におけるダム設定液面の境界（図３中でＬ）よりやや原液供給口４４寄りの位置から前記浮遊物排出口２２ｂにかけて設けられている。
【００３１】
さらに、図３に示すように、沈降物用フライト４２ａの始端側には、浮遊物を母液と共に前記浮遊物排出口２２ｂ側へ積極的に搬送させるための加速用パドル４３が連設されている。かかる加速用パドル４３の終端側は、浮遊物用フライト４２ｂの始端側に対してボウル２０軸方向に僅かに重なる位置まで延出されている。
【００３２】
次に第１実施の形態に係る遠心分離機１０の作用を説明する。
本遠心分離機１０の運転に際し、例えば、廃品プラスチックから２種のプラスチックを分離するような場合、これらの比重の中間比重を有する母液にフレーク状に破砕した廃品プラスチックを混合して原液とする。かかる原液中では、重比重のプラスチックが沈降物となり、軽比重のプラスチックが浮遊物となる。
【００３３】
図１において、原液はフィードチューブ１５を介して、ポンプ等の駆動源を用いてボウル２０内へ供給される。フィードチューブ１５から送られた原液は、スクリューコンベヤ４０の軸胴部４１の略中央にある原液供給口４４から出て、ボウル２０内のダム部２５で予め設定した所定の深さまで張り込まれる。原液はボウル２０内で遠心力（通常３００Ｇから１５００Ｇ程度）の作用を受けて、浮遊物と沈降物が母液中で分離される。
ここでボウル２０の回転方向は、フィードチューブ１５側より見て時計方向であり、スクリューコンベヤ４０が、ボウル２０と微少差速で同一回転方向に回されている。
【００３４】
遠心力の作用により分離された固形物のうち母液より比重の大きい沈降物は、ボウル２０の内周面側へ沈降し、母液より比重の小さい浮遊物はボウル２０内で母液の液面の方向に浮上する。沈降物は、ボウル２０と微少差速で回転するスクリューコンベヤ４０の沈降物用フライト４２ａによって、ボウル２０の一端側にあるテーパー部２１ａへ搬送され、予めダム部２５で設定されている液深よりも内径側へテーパー部２１ａ上を移動する際に脱液されて、沈降物排出口２２ａより外部へ排出される。
【００３５】
また、原液中の浮遊物は、前記沈降物排出口２２ａの反対側となる他方のテーパー部２１ｂに向かって母液と共に、他方のテーパー部２１ｂの始端付近まで配されている沈降物用フライト４２ａの巻きピッチ間を螺旋状に流れる。ここで母液は、他方のテーパー部２１ｂでその内周側を覆う濾材３０の隙間および壁面にある多数の孔乃至スリット２３を通り抜け、他方のテーパー部２１ｂの壁面で隔離された区画室２４１内のボウル２０内壁に複数配設されたスキミングチューブから成るダム部２５により外部へ分離排出される。
【００３６】
浮遊物は、前記沈降物用フライト４２ａの始端側に連続して繋がり、他方のテーパー部２１ｂの始端付近からテーパー部２１ｂ内周面上におけるダム設定液境界（図３中でＬ）よりやや浮遊物排出口２２ｂ側寄りの区間まで延出した加速用パドル４３によって、母液と共に他方のテーパー部２１ｂまで積極的に搬送される。さらに浮遊物は、加速用パドル４３の終端側と僅かにオーバーラップする前記浮遊物用フライト４２ｂによって、前述した沈降物とは逆方向に搬送され、予めダム部２５で設定されている液深よりも内径側へテーパー部２１ｂの濾材３０上を移動する際に濾過脱液されて、浮遊物排出口２２ｂより外部へ排出される。
【００３７】
特に本遠心分離機１０によれば、前述したようにダム部２５が、浮遊物排出口２２ｂの直ぐ手前にある他方のテーパー部２１ｂに重なる位置にあるので、ボウル２０内に供給された母液の流れと浮遊物の搬送方向が一致することになり、さらに前記加速用パドル４３の作用も相俟って、浮遊物の搬送効率をよりいっそう高めることができる。また、ダム部２５がテーパー部２１ｂの外周側に配され、浮遊物用フライト４２ｂと干渉するおそれもないため、従来のようにスキミングチューブの逃げとしてフライトの一部を切り欠く必要もない。
【００３８】
さらに、ダム部２５で規制されるボウル２０内の液深は、ダム部２５より母液が外部へ排出されている間は本来のダム設定液面を越えるので、テーパー部２１ｂの濾材３０が随時液中に没する状態が生じている。それにより、濾材３０上に滞留した浮遊物は、濾材３０が母液中に没する際に浮力により濾材３０から離脱しようとするため、テーパー部２１ｂにおける浮遊物の目詰まりを防止することも可能となる。
【００３９】
以上に述べたとおり、本実施の形態に係る遠心分離機１０では、フィードチューブ１５によりボウル２０内に供給された処理原液は、沈降物、浮遊物、それに母液の３成分に効率良く分離され、連続的に外部に排出される。図１に示されたケーシング１１の内部は、ボウル２０にある沈降物排出口２２ａ、母液排出通路であるダム部２５、浮遊物排出口２２ｂにそれぞれ対応するように区画されており、沈降物、母液および浮遊物はそれぞれ別々に回収することができる。
【００４０】
図４〜図６は本発明の第２実施の形態を示している。
本実施の形態では、ボウル２０の他方のテーパー部２６を多段状に形成し、このテーパー部２６の一部をそのままダム部を成すように設定している。なお、第１実施の形態に係る遠心分離機１０と基本的構造や機能はほぼ共通しており、同種の部位には同一符号を付して説明する。
【００４１】
他方のテーパー部２６は、その内径が漸次縮小する１段目テーパー部２６１と、該１段目テーパー部２６１の終端最小内径と略同一内径で続く中間円筒部２６２と、該中間円筒部２６２の終端よりさらに内径が漸次縮小する２段目テーパー部２６３とに区分けされた多段状に設けられている。
【００４２】
図５に示すように、他方のテーパー部２６は、ボウル２０自体の内周面が傾斜することなく、この内周面に後付けされてテーパーを成す内層壁材２７から成る。テーパー部２６のうち中間円筒部２６２は、その壁面に多数の孔乃至スリット２３を有し内周側が濾材３０で覆われている。なお、内層壁材２７において中間円筒部２６２に続く２段目テーパー部２６３についても、図示したように多数の孔乃至スリット２３を設けると良い。
【００４３】
前記中間円筒部２６２がそのままダム部を成しており、該中間円筒部２６２の内周面がダム設定液面と略一致し、テーパー部２６を成す内層壁材２７の壁面で囲まれた区画室２７１内を臨むボウル２０内壁に、母液の排出口２８が複数開設されている。
【００４４】
本実施の形態における沈降物用フライト４２ｂは、前記他方のテーパー部２６における１段目テーパー部２６１の始端付近から前記沈降物排出口２２ａにかけて設けられ、また、浮遊物用フライト４２ｂは、前記１段目テーパー部２６１の終端最小内径部位よりやや前記原液供給口４４寄りの位置から前記浮遊物排出口２２ｂにかけて設けられている。
【００４５】
図６に示すように、沈降物用フライト４２ａの始端側には、第１実施の形態と同様に加速用パドル４３が連設されているが、この加速用パドル４３の終端側は、浮遊物用フライト４２ｂの始端側に対してボウル２０軸方向に僅かに重なるように、前記中間円筒部２６２の始端よりも僅かに２段目テーパー部２６３寄りの位置まで延出されている。
【００４６】
このような第２実施の形態によれば、ボウル２０内に供給された原液中の沈降物は、ボウル２０内壁に沿うように沈降し、ボウル２０と微少差速で回転するスクリューコンベヤ４０の沈降物用フライト４２ａにより一方のテーパー部２１ａへ搬送される。ここで沈降物は、ダム部を成す他方のテーパー部２６の中間円筒部２６２で設定されている液深よりも内径側へ一方のテーパー部２１ａ上を移動する際に脱液されて、沈降物排出口２２ａより外部へ排出される。
【００４７】
原液中の浮遊物は、前記沈降物排出口２２ａの反対側となる他方のテーパー部２６に向かって母液と共に、テーパー部２６の１段目テーパー部２６１の始端付近まで配されている前記沈降物用フライト４２ａの巻きピッチ間を螺旋状に流れる。浮遊物は、前記沈降物用フライト４２ａの始端側に連続して繋がり、１段目テーパー部２６１の始端付近から中間円筒部２６２の始端よりも僅かに２段目テーパー部２６３寄りの区間まで延出した加速用パドル４３によって、１段目テーパー部２６１から中間円筒部２６２へと母液と共に積極的に搬送される。
【００４８】
母液は中間円筒部２６２において、その内周側を覆う濾材３０の隙間および壁面にある多数の孔乃至スリット２３を通り抜け、テーパー部２６の壁面で隔離された区画室２７１内のボウル２０内壁に複数開設された排出口２８より外部へ分離排出される。さらに浮遊物は、前記浮遊物用フライト４２ｂによって、前述した沈降物とは逆方向に搬送され、２段目テーパー部２６３上を移動する際に濾過脱液されて、浮遊物排出口２２ｂより外部へ排出される。
【００４９】
特に本実施の形態によれば、ボウル２０内の液深を規制するダム部を成す中間円筒部２６２は、その全長にわたって液面とほぼ同一の内周面をなしているため、テーパー部２６を覆う濾材３０が広範囲にわたり液中に没する状態が生じている。それにより、濾材３０上に滞留した浮遊物は、濾材３０が母液中に没する際に浮力によって濾材３０から離脱しようとするため、より確実にテーパー部２６における浮遊物の目詰まりを防止することが可能となる。
【００５０】
以上、本発明の実施の形態を図面によって説明してきたが、これらの具体的な構成によれば、原液から沈降物、母液および浮遊物をそれぞれ別々に回収することに関して高い処理能力を図りつつも、装置全体の小型化を実現することも可能となる。ただし、本発明はこれらの実施の形態に限定されるものではなく、本発明の要旨を逸脱しない範囲における変更や追加があっても本発明に含まれることは言うまでもない。
【００５１】
【発明の効果】
本発明に係る遠心分離機によれば、装置全体の小型化を図りながらも、原液中の沈降物と浮遊物それに母液を効率良く分離回収することができる。従来の遠心分離機が、母液と沈降物の分離に関して多くの工夫がなされているのに対し、本発明に係る遠心分離機は、多くの構造的特徴を有し、それらの特徴が浮遊物を含めた分離回収に関して特有の効果を発揮することは既に説明したとおりである。
【００５２】
特にボウル内の液深を規制すると共に母液をボウル外へ排出するダム部が、浮遊物排出口の直ぐ手前にある他方のテーパー部に重なる位置にあるので、ボウル内に供給された母液の流れと浮遊物の搬送方向が一致することになり、さらに加速用パドルの作用も相俟って、浮遊物の搬送効率をよりいっそう高めることができる。また、ダム部がテーパー部を含めてボウル内周側よりさらに内周側に突出することもなく、スクリューコンベヤと干渉するおそれもないため、従来のようにスキミングチューブの逃げとしてフライトの一部を切り欠く必要もなく、搬送効率の低下を招かないで済む。
【００５３】
さらに、ダム部で規制されるボウル内の液深は、ダム部より母液が外部へ排出されている間は本来のダム設定液面を越えるから、他方のテーパー部の濾材が随時液中に没する状態が生じているので、濾材上に滞留した浮遊物は、濾材が母液中に没する際に浮力により濾材から離脱しようとするため、濾材における浮遊物の目詰まりを防止することができる。
【図面の簡単な説明】
【図１】本発明の第１実施の形態に係る遠心分離機を示す縦断面図である。
【図２】本発明の第１実施の形態に係る遠心分離機の要部を拡大して示す縦断面図である。
【図３】本発明の第１実施の形態に係る遠心分離機の要部をさらに拡大して示す縦断面図である。
【図４】本発明の第２実施の形態に係る遠心分離機を示す縦断面図である。
【図５】本発明の第２実施の形態に係る遠心分離機の要部を拡大して示す縦断面図である。
【図６】本発明の第２実施の形態に係る遠心分離機の要部をさらに拡大して示す縦断面図である。
【図７】従来の一般的なデカンタ型の遠心分離機を概略的に示す縦断面図である。
【符号の説明】
１０…遠心分離機
１１…ケーシング
１２ａ，１２ｂ…シャフト
１３…軸受け
１４…ギヤボックス
１５…フィードチューブ
２０…ボウル
２１ａ…テーパー部
２１ｂ…テーパー部
２２ａ…沈降物排出口
２２ｂ…浮遊物排出口
２３…孔乃至スリット
２５…ダム部
２４…内層壁材
２６…テーパー部
２６１…１段目テーパー部
２６２…中間円筒部
２６３…２段目テーパー部
２７…内層壁材
２８…排出口
３０…濾材
４０…スクリューコンベヤ
４１…軸胴部
４２ａ…沈降物用フライト
４２ｂ…浮遊物用フライト
４３…加速用パドル
４４…原液供給口[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a centrifuge for separating sediment, suspended matter and mother liquor from a stock solution supplied in a bowl. Such a centrifuge is used for centrifugal separation and drainage using the specific gravity difference of crushed resins such as PVC (vinyl chloride) and PE (polyethylene) in the field of recycling waste plastics.
[0002]
[Prior art]
Conventionally, for example, such a decanter type centrifuge as shown in FIG. 7 is known. In the bowl 1, the undiluted solution is divided into precipitated particles and mother liquor by centrifugal force, and the precipitated particles are conveyed by the screw conveyor 2 given a slight rotational difference from the bowl 1, and the bowl 1 in FIG. In the figure, the liquid is discharged from the right end.
[0003]
However, the centrifugal separator is known to have various contrivances regarding the separation, washing and draining of the precipitated particles, but no measures are taken for the suspended particles contained in the stock solution. There are many things. Therefore, it is difficult to separate the suspended particles from the stock solution, and the suspended particles mixed in the liquid separated from the settled particles use, for example, a basket-type centrifuge or other solid-liquid separator. A separate process was required.
[0004]
In order to eliminate such inconveniences, for example, a wet separation apparatus described in JP-A-6-178948 has been proposed. Such a device has two screws wound in opposite directions on one shaft passing through the axis of the bowl, and conveys the precipitated particles to one end side of the rotating container by one screw, The suspended particles are conveyed to the other end side of the rotating container by a screw.
[0005]
[Problems to be solved by the invention]
In the wet separation apparatus described in the above-mentioned publication, since the settled particle conveying screw does not exist on the other end side from the approximate center of the bowl, it is different from the precipitated particle conveying screw by the movement of the floating particle conveying screw or the processing liquid. Once the settled particles move to the end side, such settled particles accumulate on the inner surface of the bowl and cannot be discharged outside the apparatus during operation. It was necessary to remove.
[0006]
In the wet separation apparatus, the mother liquor flow direction of the floating particles is transferred when the floating particles are transferred to the other end of the rotating container by the screw because the mother liquor discharge port is disposed on the settling particle discharge side. This is the opposite direction, and it is expected that the transport efficiency of suspended particles will decrease easily. If the transport efficiency of the suspended particles decreases, the sedimentation and the specific gravity separation accuracy of the suspended particles also naturally decrease.
[0007]
The present invention has been made paying attention to the above-described problems of the prior art, and reliably and efficiently separates sediment, suspended matter, and mother liquor from the stock solution without causing an increase in the size of the entire apparatus. Another object of the present invention is to provide a centrifuge capable of efficiently draining the separated substances.
[0008]
[Means for Solving the Problems]
  The gist of the present invention for achieving the object described above resides in the inventions of the following items.
[1] A centrifuge (10) for separating sediment, suspended matter and mother liquor from the stock solution supplied into the bowl (20), and is inserted into the rotating cylindrical bowl (20). The screw conveyor (40) is coaxial with the bowl (20) and rotates at a different speed, and the screw conveyor (40) has a spiral winding direction of the flight toward both ends from the middle of the shaft body (41). In the centrifuge (10) provided in opposite directions, one flight becomes a sediment flight (42a) carrying sediment, and the other flight becomes a float flight (42b) carrying float. ,
  The bowl (20) has tapered portions (21a, 21b) whose inner diameters gradually decrease at both end sides thereof, a sediment discharge port (22a) at the tip of one tapered portion (21a), and the other tapered In the compartment (241, 271) surrounded by the wall surface of the other tapered portion (21b) and the inner wall of the bowl (20) in the section, there is a suspended substance discharge port (22b) at the tip of the portion (21b). 20) Provide a dam part (25, 262) capable of regulating the liquid depth in the radial direction and discharging the mother liquid from which the suspended solids are removed to the outside of the bowl (20),
  The other tapered portion (21b) of the bowl (20) has a number of holes or slits (23) on its wall surface, and the inner peripheral side is covered with the filter medium (30),
  The dam portion (25) is composed of a plurality of circumferentially arranged skimming tubes on the inner wall of the bowl (20) facing the compartment (241), and is set by a dam setting that is regulated by the protruding tip of each skimming tube. The liquid level is set at a position covering the middle of the inclination of the other tapered portion (21b),
  The means for supplying the stock solution into the bowl (20) allows the feed tube (15) to be inserted into the shaft body (41) of the screw conveyor (40) and communicates with the outlet of the feed tube (15). Opening the stock solution supply port (44) at the approximate center of the shaft barrel (41),
  The sediment flight (42a) has a tip on the inner wall of the ball (20) including the one tapered portion (21a) from the vicinity of the start end of the other tapered portion (21b) to the sediment discharge port (22a). Provided along,
  The suspended matter flight (42b) is disposed on the inner peripheral surface of the other tapered portion (21b) from a position slightly closer to the stock solution supply port (44) than the boundary of the dam setting liquid surface, 22b) so that the tip is along the inner wall of the ball (20) including the other tapered portion (21b).,
  An acceleration paddle (43) for actively transporting suspended matter together with mother liquor to the suspended matter discharge port (22b) side is connected to the start side of the sediment flight (42a), and the acceleration paddle is connected. The end side of (43) is extended to a position slightly overlapping in the axial direction of the bowl (20) with respect to the start end side of the flight for suspended matter (42b).A centrifuge (10) characterized in that.
[0012]
[2A centrifuge (10) for separating sediment, suspended matter, and mother liquor from the stock solution supplied into the bowl (20), the bowl being inserted into the rotating cylindrical bowl (20) The screw conveyor (40) is coaxial with (20) and rotates at a different speed, and the screw conveyor (40) has a spiral winding direction of the flight opposite to both ends from the middle of the shaft body (41). In the centrifuge (10), which is provided in a direction, one flight becomes a sediment flight (42a) for transporting sediment, and the other flight becomes a flight for float (42b) for transporting suspended matter.
  The bowl (20) has tapered portions (21a, 21b) whose inner diameters gradually decrease at both end sides thereof, a sediment discharge port (22a) at the tip of one tapered portion (21a), and the other tapered In the compartment (241, 271) surrounded by the wall surface of the other tapered portion (21b) and the inner wall of the bowl (20) in the section, there is a suspended substance discharge port (22b) at the tip of the portion (21b). 20) Provide a dam part (25, 262) capable of regulating the liquid depth in the radial direction and discharging the mother liquid from which the suspended solids are removed to the outside of the bowl (20),
  The other taper part (26) of the bowl (20) continues with a first-stage taper part (261) whose inner diameter gradually decreases, and an inner diameter that is substantially the same as the terminal minimum inner diameter of the first-stage taper part (261). The intermediate cylindrical portion (262) is provided in a multi-stage shape divided into a second-stage tapered portion (263) whose inner diameter gradually decreases further from the end of the intermediate cylindrical portion (262), and the intermediate cylindrical portion (262) Has a large number of holes or slits (23) on its wall surface and the inner peripheral side is covered with the filter medium (30),
  The intermediate cylindrical portion (262) forms the dam portion as it is, and an inner peripheral surface of the intermediate cylindrical portion (262) substantially coincides with a dam setting liquid surface, and at least the intermediate portion of the other tapered portion (26). A centrifuge (10) characterized in that a plurality of mother liquor discharge ports (28) are provided in the inner wall of the bowl (20) facing the compartment (271) surrounded by the wall surface of the cylindrical portion (262).
[0013]
[3The means for supplying the stock solution into the bowl (20) is inserted into the shaft barrel (41) of the screw conveyor (40) and communicated with the outlet of the feed tube (15). A stock solution supply port (44) to be opened at the approximate center of the shaft barrel (41),
  The flight for sediment (42a) is provided from the vicinity of the start end of the first taper portion (261) in the other taper portion (26) to the sediment discharge port (22a),
  The floating flight (42b) is provided from a position slightly closer to the stock solution supply port (44) to the floating discharge port (22b) than the terminal end minimum inner diameter portion of the first-stage tapered portion (261). Featuring [2] The centrifuge (10) of description.
[0014]
[4An acceleration paddle (43) for positively transporting suspended matter together with mother liquor to the suspended matter discharge port (22b) side is connected to the starting end side of the sediment flight (42a). The end side of the paddle (43) is slightly above the start end of the intermediate cylindrical part (262) so as to slightly overlap the start end side of the flight (42b) for the suspended matter in the axial direction of the bowl (20). It is characterized by extending to a position closer to the second stage taper part (263) [3] The centrifuge (10) of description.
[0015]
Next, the operation of the present invention will be described.
According to the centrifugal separator (10) of the present invention, the stock solution established in the shaft barrel (41) through the feed tube (15) inserted through the shaft barrel (41) of the screw conveyor (40). The sediment in the undiluted solution supplied into the bowl (20) from the supply port (44) settles along the inner wall of the bowl (20), and rotates with a slight difference speed from the bowl (20). ) To the one tapered portion (21a) by the sediment flight (42a). Here, the sediment is drained when moving on the taper portion (21a) to the inner diameter side from the liquid depth set in advance in the dam portion (25), and is sent to the outside from the sediment discharge port (22a). Discharged.
[0016]
Further, the suspended matter in the stock solution is disposed to the vicinity of the beginning of the other tapered portion (21b) together with the mother liquid toward the other tapered portion (21b) on the opposite side of the sediment discharge port (22a). It flows spirally between the winding pitches of the flights for sediment (42a). Here, the mother liquor passes through the gap of the filter medium (30) covering the inner peripheral side with the other taper portion (21b) and a large number of holes or slits (23) on the wall surface, and is surrounded by the wall surface of the taper portion (21b). The plurality of skimming tubes provided on the inner wall of the bowl (20) facing the compartment (241) are separated and discharged to the outside.
[0017]
The suspended matter is continuously connected to the starting end side of the sediment flight (42a), and is slightly suspended from the dam setting liquid boundary on the inner peripheral surface of the tapered portion (21b) from the vicinity of the starting end of the other tapered portion (21b). By the acceleration paddle (43) extending to the section closer to the discharge port (22b), it is positively conveyed together with the mother liquid to the other tapered portion (21b).
[0018]
Further, the suspended matter floats from a position slightly closer to the stock solution supply port (44) than the dam setting liquid level boundary on the inner peripheral surface of the tapered portion (21b) slightly overlapping the terminal side of the acceleration paddle (43). The suspended matter flight (42b) arranged in the section to the material discharge port (22b) is transported in the opposite direction to the sediment described above, and has an inner diameter larger than the liquid depth previously set in the dam part (25). When moving on the tapered portion (21b) to the side, it is filtered and drained, and is discharged to the outside through the suspended matter discharge port (22b).
[0019]
Moreover, according to the centrifuge (10) which concerns on another invention, the sediment in the undiluted solution supplied in the bowl (20) settles along the inner wall of the bowl (20), and the bowl (20). And is conveyed to one taper part (26) by the flight for precipitates (42a) of the screw conveyor rotating at a slight difference speed. Here, the sediment moves on one taper part (21a) to the inner diameter side from the liquid depth previously set in the dam part, that is, the intermediate cylindrical part (262) of the multi-stage taper part (26) on the other side. When draining, it is drained and discharged to the outside through the sediment discharge port (22a).
[0020]
The suspended matter in the undiluted solution is mixed with the mother liquid toward the other multi-stage tapered section (26) on the opposite side of the sediment discharge port (22a), and the first-stage tapered section of the multi-stage tapered section (26) ( 261) spirally flows between winding pitches of the sediment flight (42a) arranged to the vicinity of the start end. The suspended matter is continuously connected to the start end side of the flight for sediment (42a), and from the vicinity of the start end of the first step taper portion (261) to the second step taper portion slightly from the start end of the intermediate cylindrical portion (262). (263) The acceleration paddle (43) extending to the section closer to (263) is positively conveyed along with the mother liquor from the first-stage tapered portion (261) to the intermediate cylindrical portion (262).
[0021]
In the intermediate cylindrical part (262), the mother liquor passed through the gaps of the filter medium (30) covering the inner peripheral side and a large number of holes or slits (23) in the wall surface, and was isolated at least by the wall surface of the intermediate cylindrical part (262). Separated and discharged to the outside through a plurality of outlets (28) provided in the inner wall of the bowl (20) in the compartment (271). Further, the suspended matter is introduced from the position slightly closer to the stock solution supply port (44) than the end of the minimum inner diameter of the first stage tapered portion (261) slightly overlapped with the termination portion of the acceleration paddle (43). 22b), the suspended matter flight (42b) arranged in the section up to 22b) is transported in the direction opposite to the sediment described above, filtered and drained when moving on the second taper portion (263), It is discharged to the outside through the floating material discharge port (22b).
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, various embodiments representing the present invention will be described with reference to the drawings.
1 to 3 show a first embodiment of the present invention.
As shown in FIG. 1, the centrifuge 10 according to the present embodiment has a screw conveyor 40 inserted in a cylindrical (tubular) bowl 20, as in a device commonly called a decanter centrifuge. These are supported so as to be relatively rotatable, and are configured such that sediment, suspended matter, and mother liquor can be separately separated from the stock solution supplied into the bowl 20.
[0023]
As shown in FIG. 1, the bowl 20 and the screw conveyor 40 inside the bowl 20 are rotatably supported inside the casing 11 via shafts 12 a and 12 b. The bowl 20 and the screw conveyor 40 are rotationally driven at a slight differential speed by a gear box 14 connected to the bearing 13 on one side. Such a rotational drive mechanism is well known and will not be described in detail.
[0024]
One end side (right side in FIG. 1) of the bowl 20 is a sediment discharging direction, and a tapered portion 21a whose inner diameter is gradually reduced is formed on the one end side. A plurality of sediment discharge ports 22a are provided in the circumferential direction at the tip (end side) of the tapered portion 21a. Further, the other end side (left side in FIG. 1) of the bowl 20 is in the direction of discharging the suspended matter, and a tapered portion 21b whose inner diameter is gradually reduced is formed on the other end side. A plurality of suspended matter discharge ports 22b are formed in the circumferential direction at the tip (end side) of the tapered portion 21b.
[0025]
One tapered portion 21a is formed by inclining the inner peripheral surface of the bowl 20 itself, while the other tapered portion 21b is formed on the inner peripheral surface without inclining the inner peripheral surface of the bowl 20 itself. It consists of an inner layer wall member 24 which is retrofitted and forms a taper. As shown in FIG. 2, the other tapered portion 21 b has a large number of holes or slits 23 on its wall surface, and the inner peripheral side is covered with a filter medium 30. In addition, it is preferable to provide a large number of holes or slits 23 as shown in the figure for the cylindrical portion of the inner layer wall member 24 that is not actually tapered.
[0026]
The diameter and width of the holes or slits 23 do not require much consideration of the particle size of the suspended matter, but the filter medium 30 is made of a material having a large number of micropores or slits having a smaller diameter than the particle size of the suspended matter. Specifically, it may be formed by a porous ceramic molded body, a segment type screen (divided block screen) or the like in addition to a punched hole type screen and a wedge wire screen that have been conventionally used. In addition, the surface of the inner peripheral side of the taper portion 21 b is slightly shaved by the thickness of the filter medium 30.
[0027]
In the compartment 241 surrounded by the wall surface of the other tapered portion 21b and the inner wall of the bowl 20 in that section, the liquid depth in the radial direction of the bowl 20 can be regulated and the mother liquid from which suspended matters have been removed can be discharged out of the bowl 20. A dam portion 25 is provided. The dam portion 25 is composed of a plurality of skimming tubes arranged in the circumferential direction on the inner wall of the bowl 20 facing the compartment 241. The dam setting liquid level regulated by the projecting tip port 241 of each skimming tube is set at a position that covers the taper portion 21b up to the middle of the inclination.
[0028]
Here, since the dam portion 25 is positioned so as to overlap with the other tapered portion 21b immediately before the suspended matter discharge port 22b, the flow of the mother liquor supplied into the bowl 20 and the conveying direction of the suspended matter coincide with each other. Become. Further, the liquid depth in the bowl 20 regulated by the dam portion 25 exceeds the original dam setting liquid level while the mother liquor is discharged from the dam portion 25 to the outside, so that the filter medium 30 of the taper portion 21b is liquid at any time. There is a state of sinking inside.
[0029]
In the screw conveyor 40, the spiral winding direction of the flight is provided in opposite directions toward the both ends from the middle of the shaft body 41, and one flight becomes a sediment flight 42a for transporting sediment, and the other flight is It becomes the floating object flight 42b which conveys a floating substance. Further, the feed tube 15 is inserted into the shaft body portion 41, and a plurality of stock solution supply ports 44 communicating with the outlet of the feed tube 15 are formed at a substantially center of the shaft body portion 41.
[0030]
The sediment flight 42a is provided from the vicinity of the starting end of the other tapered portion 21b to the sediment discharge port 22a. The suspended matter flight 42b extends from a position slightly closer to the stock solution supply port 44 to the suspended matter discharge port 22b from the boundary (L in FIG. 3) of the dam setting liquid level on the inner peripheral surface of the other tapered portion 21b. Is provided.
[0031]
Further, as shown in FIG. 3, an acceleration paddle 43 is provided on the start end side of the sediment flight 42a so as to actively transport the suspended matter together with the mother liquid to the suspended matter discharge port 22b. . The terminal side of the acceleration paddle 43 extends to a position where it slightly overlaps with the starting end side of the suspended matter flight 42b in the bowl 20 axial direction.
[0032]
Next, the operation of the centrifuge 10 according to the first embodiment will be described.
When the centrifugal separator 10 is operated, for example, when two kinds of plastics are separated from the waste plastics, the waste plastics crushed into flakes are mixed with a mother liquor having an intermediate specific gravity to obtain a stock solution. In such a stock solution, the high specific gravity plastic becomes a sediment, and the light specific gravity plastic becomes a suspended matter.
[0033]
In FIG. 1, the stock solution is supplied into the bowl 20 through a feed tube 15 using a drive source such as a pump. The stock solution sent from the feed tube 15 exits from the stock solution supply port 44 at the approximate center of the shaft barrel portion 41 of the screw conveyor 40 and is stretched to a predetermined depth set in advance in the dam portion 25 in the bowl 20. The undiluted solution is subjected to centrifugal force (usually about 300 to 1500 G) in the bowl 20, and the suspended matter and sediment are separated in the mother liquor.
Here, the rotation direction of the bowl 20 is clockwise when viewed from the feed tube 15 side, and the screw conveyor 40 is rotated in the same rotation direction as the bowl 20 at a slight differential speed.
[0034]
Of the solids separated by the action of centrifugal force, the sediment having a specific gravity greater than that of the mother liquor settles toward the inner peripheral surface of the bowl 20, and the suspended matter having a specific gravity smaller than that of the mother liquor is oriented in the direction of the liquid level of the mother liquor in the bowl 20. To surface. The sediment is transported to the tapered portion 21a on one end side of the bowl 20 by the sediment flight 42a of the screw conveyor 40 that rotates at a slight difference speed with the bowl 20, and from the liquid depth set in advance by the dam portion 25. Is also drained when moving on the taper portion 21a toward the inner diameter side, and is discharged to the outside through the sediment discharge port 22a.
[0035]
In addition, the suspended matter in the stock solution flows along with the mother liquid toward the other taper portion 21b on the opposite side of the sediment discharge port 22a, to the vicinity of the start end of the other taper portion 21b. It flows spirally between winding pitches. Here, the mother liquor passes through a large number of holes or slits 23 in the wall surface of the filter medium 30 and the wall surface of the other taper portion 21b, and passes through the gaps of the filter medium 30 that covers the inner peripheral side of the other taper portion 21b. A plurality of skimming tubes disposed on the inner wall of the bowl 20 are separated and discharged outside.
[0036]
The suspended matter is continuously connected to the starting end side of the sediment flight 42a and floats slightly from the dam setting liquid boundary (L in FIG. 3) on the inner peripheral surface of the tapered portion 21b from the vicinity of the starting end of the other tapered portion 21b. By the acceleration paddle 43 extending to the section closer to the object discharge port 22b, it is positively transported to the other tapered portion 21b together with the mother liquor. Further, the suspended matter is transported in a direction opposite to the above-described sediment by the suspended matter flight 42b slightly overlapping the terminal side of the acceleration paddle 43, and from the liquid depth previously set in the dam portion 25. Also, when moving on the filter medium 30 of the tapered portion 21b toward the inner diameter side, it is filtered and drained, and is discharged to the outside through the suspended matter discharge port 22b.
[0037]
In particular, according to the present centrifugal separator 10, as described above, the dam portion 25 is positioned so as to overlap the other tapered portion 21 b immediately in front of the suspended matter discharge port 22 b, so that the mother liquid supplied into the bowl 20 can be removed. The flow and the transport direction of the floating substance coincide with each other, and further, the action of the acceleration paddle 43 can be combined to further increase the transport efficiency of the floating substance. Further, since the dam portion 25 is arranged on the outer peripheral side of the tapered portion 21b and there is no possibility of interfering with the suspended matter flight 42b, it is not necessary to cut out a part of the flight as a skimming tube escape as in the prior art.
[0038]
Furthermore, the liquid depth in the bowl 20 regulated by the dam part 25 exceeds the original dam setting liquid level while the mother liquor is discharged from the dam part 25 to the outside. There is a state of sinking inside. Thereby, since the suspended matter staying on the filter medium 30 tends to be separated from the filter medium 30 by buoyancy when the filter medium 30 is submerged in the mother liquor, it is possible to prevent clogging of the suspended matter in the tapered portion 21b. Become.
[0039]
As described above, in the centrifuge 10 according to the present embodiment, the processing stock solution supplied into the bowl 20 by the feed tube 15 is efficiently separated into the three components of sediment, suspended matter, and mother liquor, Continuously discharged outside. The inside of the casing 11 shown in FIG. 1 is partitioned so as to correspond to the sediment discharge port 22a in the bowl 20, the dam portion 25 that is a mother liquor discharge passage, and the floating material discharge port 22b, respectively. Mother liquor and suspended solids can be collected separately.
[0040]
4 to 6 show a second embodiment of the present invention.
In the present embodiment, the other tapered portion 26 of the bowl 20 is formed in a multi-stage shape, and a part of the tapered portion 26 is set to form a dam portion as it is. The basic structure and function are substantially the same as those of the centrifuge 10 according to the first embodiment, and the same reference numerals are given to the same types of parts.
[0041]
The other taper portion 26 includes a first-stage taper portion 261 whose inner diameter gradually decreases, an intermediate cylindrical portion 262 that continues with substantially the same inner diameter as the terminal minimum inner diameter of the first-stage taper portion 261, and the intermediate cylindrical portion 262. It is provided in a multi-stage shape divided into a second-stage tapered portion 263 whose inner diameter gradually decreases further from the end.
[0042]
As shown in FIG. 5, the other tapered portion 26 is composed of an inner wall material 27 that is retrofitted to the inner peripheral surface and forms a taper without the inner peripheral surface of the bowl 20 itself being inclined. Of the tapered portion 26, the intermediate cylindrical portion 262 has a large number of holes or slits 23 on its wall surface, and the inner peripheral side is covered with the filter medium 30. It should be noted that a plurality of holes or slits 23 may be provided in the second-stage tapered portion 263 following the intermediate cylindrical portion 262 in the inner layer wall material 27 as shown in the figure.
[0043]
The intermediate cylindrical portion 262 forms a dam portion as it is, and the inner peripheral surface of the intermediate cylindrical portion 262 substantially coincides with the dam setting liquid surface and is surrounded by the wall surface of the inner layer wall material 27 forming the tapered portion 26. A plurality of mother liquid discharge ports 28 are formed in the inner wall of the bowl 20 facing the chamber 271.
[0044]
The sediment flight 42b in the present embodiment is provided from the vicinity of the starting end of the first-stage tapered portion 261 in the other tapered portion 26 to the sediment discharge port 22a, and the suspended matter flight 42b is the first flight portion 42b. It is provided from the position slightly closer to the stock solution supply port 44 to the suspended matter discharge port 22b than the terminal minimum inner diameter portion of the step taper portion 261.
[0045]
As shown in FIG. 6, an acceleration paddle 43 is connected to the start end side of the sediment flight 42a in the same manner as in the first embodiment. The intermediate flight portion 262 extends slightly to a position closer to the second-stage tapered portion 263 so as to slightly overlap the start end side of the flight 42b in the bowl 20 axial direction.
[0046]
According to such a second embodiment, the sediment in the undiluted solution supplied into the bowl 20 settles along the inner wall of the bowl 20 and settles on the screw conveyor 40 that rotates at a slight differential speed from the bowl 20. It is conveyed to one taper part 21a by the thing flight 42a. Here, the sediment is drained when moving on one tapered portion 21a toward the inner diameter side of the liquid depth set by the intermediate cylindrical portion 262 of the other tapered portion 26 forming the dam portion, and the sediment is obtained. It is discharged to the outside through the discharge port 22a.
[0047]
The suspended matter in the undiluted solution is disposed up to the vicinity of the beginning of the first tapered portion 261 of the tapered portion 26 together with the mother liquid toward the other tapered portion 26 on the opposite side of the sediment discharge port 22a. It flows spirally between the winding pitches of the flights 42a. The suspended matter is continuously connected to the start end side of the sediment flight 42a and extends from the vicinity of the start end of the first stage taper portion 261 to a section slightly closer to the second step taper portion 263 than the start end of the intermediate cylindrical portion 262. The acceleration paddle 43 that has been taken out is positively conveyed together with the mother liquor from the first-stage tapered portion 261 to the intermediate cylindrical portion 262.
[0048]
In the intermediate cylindrical part 262, the mother liquor passes through a large number of holes or slits 23 on the wall surface of the filter medium 30 covering the inner peripheral side thereof, and a plurality of holes are formed on the inner wall of the bowl 20 in the compartment 271 isolated by the wall surface of the tapered part 26. Separated and discharged from the established discharge port 28. Further, the suspended matter is transported in the direction opposite to the above-described sediment by the suspended matter flight 42b, and is filtered and drained when moving on the second-stage tapered portion 263, and is then discharged from the suspended matter outlet 22b. Is discharged.
[0049]
In particular, according to the present embodiment, the intermediate cylindrical portion 262 that forms the dam portion that regulates the liquid depth in the bowl 20 has an inner peripheral surface that is substantially the same as the liquid surface over the entire length thereof, so that the tapered portion 26 is formed. There is a state in which the covering filter medium 30 is immersed in the liquid over a wide range. Thereby, since the suspended matter staying on the filter medium 30 tends to be separated from the filter medium 30 by buoyancy when the filter medium 30 is submerged in the mother liquor, the suspended matter is more reliably prevented from being clogged in the tapered portion 26. Is possible.
[0050]
As mentioned above, although embodiment of this invention has been demonstrated with drawing, according to these specific structures, while aiming at high processing capability regarding collect | recovering sediment, mother liquor, and suspended | floating matter from stock solution separately, respectively. It is also possible to reduce the size of the entire apparatus. However, the present invention is not limited to these embodiments, and it goes without saying that modifications and additions within the scope not departing from the gist of the present invention are included in the present invention.
[0051]
【The invention's effect】
According to the centrifuge according to the present invention, it is possible to efficiently separate and collect the sediment, suspended matter and mother liquor in the stock solution while reducing the size of the entire apparatus. Whereas conventional centrifuges have been devised in many ways for separating mother liquor and sediment, the centrifuge according to the present invention has many structural features, and these features are free from suspended solids. As described above, the specific effects of the separation and recovery are included.
[0052]
In particular, the dam that regulates the depth of the liquid in the bowl and discharges the mother liquor to the outside of the bowl is positioned so as to overlap the other tapered portion just in front of the suspended matter discharge port. The transport direction of the suspended matter coincides with that of the acceleration paddle, and the suspended matter transport efficiency can be further enhanced. In addition, the dam part does not protrude further from the inner circumference side of the bowl including the taper part, and there is no possibility of interference with the screw conveyor. There is no need to cut out and it is not necessary to cause a decrease in conveying efficiency.
[0053]
Furthermore, the liquid depth in the bowl regulated by the dam part exceeds the original dam setting liquid level while the mother liquor is discharged from the dam part, so the filter material of the other tapered part is immersed in the liquid as needed. Therefore, the suspended matter staying on the filter medium tends to be separated from the filter medium by buoyancy when the filter medium is submerged in the mother liquor, so that the suspended matter in the filter medium can be prevented from being clogged.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a centrifuge according to a first embodiment of the present invention.
FIG. 2 is an enlarged longitudinal sectional view showing a main part of the centrifuge according to the first embodiment of the present invention.
FIG. 3 is a longitudinal cross-sectional view further enlarging a main part of the centrifuge according to the first embodiment of the present invention.
FIG. 4 is a longitudinal sectional view showing a centrifuge according to a second embodiment of the present invention.
FIG. 5 is an enlarged longitudinal sectional view showing a main part of a centrifuge according to a second embodiment of the present invention.
FIG. 6 is a longitudinal sectional view showing a main part of a centrifuge according to a second embodiment of the present invention further enlarged.
FIG. 7 is a longitudinal sectional view schematically showing a conventional general decanter type centrifuge.
[Explanation of symbols]
10 ... centrifuge
11 ... Casing
12a, 12b ... shaft
13 ... Bearing
14 ... Gearbox
15 ... feed tube
20 ... Bowl
21a ... taper part
21b ... taper part
22a ... sediment outlet
22b ... Float discharge port
23 ... hole or slit
25 ... Dam Club
24 ... Inner wall material
26 ... Taper
261 ... First stage taper
262 ... Intermediate cylindrical part
263 ... 2nd stage taper
27 ... Inner wall material
28 ... Discharge port
30 ... Filter media
40 ... Screw conveyor
41 ... Shaft body
42a ... Sediment flight
42b ... Float flight
43 ... Acceleration paddle
44 ... Stock solution supply port

Claims

A centrifuge for separating sediment, suspended matter and mother liquor from a raw solution supplied in a bowl, which is inserted into the rotating cylindrical bowl and rotates at a different speed coaxially with the bowl The screw conveyor is provided with the spiral winding direction of the flight from the middle of the shaft barrel part in opposite directions toward both ends, and one flight becomes a sediment flight for transporting the sediment, Flight is a centrifuge that becomes a flight for suspended matter that carries suspended matter.
The bowl has tapered portions whose inner diameters gradually decrease at both ends thereof, a sediment discharge port is provided at the tip of one taper portion, a floating material discharge port is provided at the tip of the other taper portion, and the other taper is provided. In the compartment surrounded by the wall surface of the part and the inner wall of the bowl in the section, a dam part that regulates the liquid depth in the radial direction of the bowl and discharges the mother liquid from which the suspended matter has been removed to the outside of the bowl,
The other tapered portion of the bowl has a large number of holes or slits on its wall surface, and the inner peripheral side is covered with a filter medium,
The dam portion is composed of a plurality of skimming tubes arranged in the circumferential direction on the inner wall of the bowl facing the compartment, and the dam setting liquid level regulated by the protruding tip port of each skimming tube is the height of the other tapered portion. Set to cover the middle of the slope,
The means for supplying the stock solution into the bowl is formed by inserting a feed tube into the shaft barrel portion of the screw conveyor, and opening a stock solution supply port communicating with the outlet of the feed tube at substantially the center of the shaft barrel portion. ,
The flight for sediment is provided so that the tip is along the inner wall of the ball including the one tapered portion from the vicinity of the start end of the other tapered portion to the sediment discharge port,
The flight for floating matter includes the other tapered portion from the position of the dam setting liquid level on the inner peripheral surface of the other tapered portion to a position closer to the stock solution supply port to the floating matter discharge port. The tip is provided along the inner wall ,
An acceleration paddle for actively transporting the suspended matter together with the mother liquor to the suspended matter discharge side is connected to the start end side of the sediment flight, and the terminal side of the acceleration paddle is connected to the suspended matter for the suspended matter. A centrifuge characterized by extending to a position slightly overlapping with the start end side of the flight in the bowl axial direction .

A centrifuge for separating sediment, suspended matter and mother liquor from a raw solution supplied in a bowl, which is inserted into the rotating cylindrical bowl and rotates at a different speed coaxially with the bowl The screw conveyor is provided with the spiral winding direction of the flight from the middle of the shaft barrel part in opposite directions toward both ends, and one flight becomes a sediment flight for transporting the sediment, Flight is a centrifuge that becomes a flight for suspended matter that carries suspended matter.
The bowl has tapered portions whose inner diameters gradually decrease at both ends thereof, a sediment discharge port is provided at the tip of one taper portion, a floating material discharge port is provided at the tip of the other taper portion, and the other taper is provided. In the compartment surrounded by the wall surface of the part and the inner wall of the bowl in the section, a dam part that regulates the liquid depth in the radial direction of the bowl and discharges the mother liquid from which the suspended matter has been removed to the outside of the bowl,
The other taper portion of the bowl includes a first-stage taper portion whose inner diameter gradually decreases, an intermediate cylindrical portion that has an inner diameter that is substantially the same as an end minimum inner diameter of the first-stage taper portion, and an end of the intermediate cylindrical portion. Furthermore, it is provided in a multi-stage shape divided into a second-stage tapered portion whose inner diameter gradually decreases, and the intermediate cylindrical portion has a large number of holes or slits on its wall surface and the inner peripheral side is covered with a filter medium,
The intermediate cylindrical portion directly forms the dam portion, the inner peripheral surface of the intermediate cylindrical portion substantially coincides with the dam setting liquid level, and is surrounded by at least the wall surface of the intermediate cylindrical portion of the other tapered portion. A centrifuge having a plurality of mother liquor outlets on the inner wall of the bowl facing the compartment.

The means for supplying the stock solution into the bowl is formed by inserting a feed tube into the shaft barrel portion of the screw conveyor, and opening a stock solution supply port communicating with the outlet of the feed tube at substantially the center of the shaft barrel portion. ,
The flight for sediment is provided from the vicinity of the start end of the first-stage tapered portion in the other tapered portion to the sediment discharge port,
3. The centrifugal separator according to claim 2 , wherein the flight for floating matter is provided from a position slightly closer to the stock solution supply port to the floating matter discharge port than a terminal minimum inner diameter portion of the first stage tapered portion. .

An acceleration paddle for actively transporting the suspended matter together with the mother liquor to the suspended matter discharge side is connected to the start end side of the sediment flight, and the terminal side of the acceleration paddle is connected to the suspended matter for the suspended matter. 4. The device according to claim 3 , wherein the first cylindrical portion extends slightly to a position closer to the second taper portion than the starting end of the intermediate cylindrical portion so as to slightly overlap the starting end side of the flight in the bowl axial direction. centrifuge.