JP4057077B2

JP4057077B2 - Rotating drum type nonmagnetic metal sorting and collecting device

Info

Publication number: JP4057077B2
Application number: JP17756196A
Authority: JP
Inventors: 正男緒方
Original assignee: Senqcia Corp
Current assignee: Senqcia Corp
Priority date: 1996-06-18
Filing date: 1996-06-18
Publication date: 2008-03-05
Anticipated expiration: 2016-06-18
Also published as: JPH10380A

Description

【０００１】
【発明の属する技術分野】
本発明は、アルミニウム、銅等の導電性非磁性金属を処理物中より分離、回収するための回転ドラム型非磁性金属選別回収装置に関し、特に小口径の導電性非磁性金属片を回収するための回転ドラム型非磁性金属選別回収装置に関するものである。
【０００２】
【従来の技術】
近年、環境問題が注目される中、資源の再利用化も進んでおり、日常発生する廃棄物の中から、鉄はもとより非鉄金属類、紙、布類、木片、合成樹脂、ゴム、ガラス等広い範囲で資源回収が行われ、それに伴う回収システムにも新しい技術が採用されている。
非鉄金属の中でアルミニウムに代表される非磁性軽金属類を選別回収する装置は、都市ごみの中のアルミ缶、あるいは自動車廃車の裁断スクラップに含まれるアルミニウム等の回収再利用に多用されている。
非鉄金属を他の廃棄物と選別回収する手段として磁力を応用したものは、従来より、移動交流磁界を応用したリニアモータ型、ロータリーキルン状回転円筒の外周に永久磁石を配設したインサイドドラム型、平滑斜面の下側に永久磁石を配列したスライディングセパレータ型、あるいはコンベアベルトが巻装されるドラムを二重構造のドラム型とし内部に永久磁石回転子を配設した回転ドラム型等、多数の構造が提案されている。
【０００３】
上記の中で回転ドラム型が最も多く使用されており、その従来例を図１１に示す。図１１において、無端状のコンベアベルト１０は一方の端部を駆動ローラ９に、他方の端部をドラム１に巻装されている。駆動ローラ９をモータ７によりＶベルト８を介して矢印ＲＲの方向に回転駆動することにより、コンベアベルト１０を矢印ＲＢの方向に走行させる。従って、従動ローラであるドラム１は矢印ＲＤで示す方向に回転する。また、ドラム１は非磁性材料で形成されており、ドラム１の内部にはドラム１と同心状に永久磁石回転子４が回転自在に配設されている。
【０００４】
次に上記永久磁石回転子４の構成を図１２に示す。円筒磁性部材３の外周面上に磁石２と磁石２´が、円周方向に沿って等角度間隔で交互にＮ極とＳ極がドラム１側に位置するように、かつそれらの外表面がドラム１の内周面に近接するように固設されている。また、永久磁石回転子４はドラム１と同心で回転方向ＲＤと同一方向ＲＭに回転するが、回転速度（周速）が異なるように別のモータ６によりＶベルト５を介して回転駆動する二重構造になっている。なお、永久磁石回転子４の回転速度は、ドラム１の回転速度よりも充分に大きくなるように設定されている。
【０００５】
このようにして、磁石２のＮ極から流出した磁束Ｃは、ドラム１およびその上に巻装されたコンベアベルト１０を通過して磁石２´のＳ極に流入するので、コンベアベルト１０の表面に強力な磁界を発生させることになり、処理物（１４あるいは１５）に種々の影響を与える。さらにドラム１の前方下側には、コンベアベルト１０から落下し選別される処理物を回収する容器１８、１９が配設され、容器１８には紙、布類、木片、合成樹脂等の非金属片１４、容器１９にはアルミニウム、銅等の導電性非磁性金属片１５がそれぞれ回収される。
【０００６】
上記の回転ドラム型非磁性金属選別回収装置の動作は次の通りである。
まず、導電性非磁性金属片１５、非金属片１４が混在した処理物をホッパ１３の上端開放部から投入すると、コンベアベルト１０の表面に落下し、コンベアベルト１０の走行と共にドラム１の中心軸を通る垂線の上部領域、すなわち最頂部へと搬送される。ここで、コンベアベルト１０上の処理物はある程度の厚さを持ち層状となるが、理解を容易にするために図１１では散在した状態で示す。
【０００７】
処理物は、ドラム１の最頂部に達すると、ドラム１に内設された永久磁石回転子４の高速回転により、円筒磁性部材３の外周面に固設された磁石２および磁石２´によって発生する高周波交番磁界の中を通過する。この時、導電性非磁性金属片１５の内部にはファラデーの電磁誘導で説明される渦電流が発生し、この渦電流に起因して発生する磁束の向きと、永久磁石回転子４より発生する磁束の向きは、レンツの法則に従って相反するため、両者の相互作用により遠心方向の斥力（反発力）が生起される。さらにコンベアベルト１０の搬送力が合成力として作用して、導電性非磁性金属片１５はコンベアベルト１０の走行方向から見てその前方でかつ上方に飛翔し、ドラム１のほぼ最頂部より放物線の軌跡ａを描いて落下し、容器１９へと選別回収される。
【０００８】
また、処理物中の非金属片１４は、磁石２および磁石２´の磁気作用を何等受けることが無いため、自重により自由落下して、ｂの軌跡に沿って容器１８へ選別回収される。
【０００９】
従来の永久磁石回転子４の１／４断面図を図１３に示す。図１３は、磁石２と磁石２´が、円筒磁性部材３の外周面上に円周方向に沿って３０°の等角度間隔で固設された場合を示す。
磁石の磁化を弱めようとして磁石内を走る反磁場は、Ｎ極とＳ極の距離が遠くなるにつれ小さくなる。従って、反磁場の影響を少なくし磁石の磁気を強くするためには、磁石を固設する部材を鉄などの磁性材料で形成し、隣合う磁石の磁気回路を接続して磁石内のＮ極とＳ極の距離を長くすれば良いことは一般に知られている。
図１３において反時計方向の角度をθとすると、ドラム１の外表面法線方向の磁束密度Ｂと角度θの関係（磁束密度分布）は図１４のようになる。なお、角度θが１５°以上になると周期的に同様な磁束密度曲線を描くため、角度θは０°〜１５°の範囲で示す。
【００１０】
一般に、導電性非磁性金属片が永久磁石回転子より受ける斥力Ｆは次の式で表される。
Ｆ∝Ｂｇ²×ｆ×σ×Ａ／ρ…………（１）
ここでＢｇ：磁束密度
ｆ：周波数（＝磁石ドラム極数×磁石ドラム回転数）
σ ：導電率
Ａ：処理物表面積
ρ ：密度
選別回収の対象である導電性非磁性金属片１５が小口径の場合、その表面積は小さくなり、斥力Ｆが小さくなることが式（１）から理解できる。
【００１１】
【発明が解決しようとする課題】
従来の回転ドラム型非磁性金属選別回収装置では、導電性非磁性金属片が小口径になると、永久磁石回転子より受ける斥力が小さくなり、確実な選別回収が困難であるという問題点があった。
また、導電性非磁性金属片の形状が一様ではないため、空気抵抗等の理由で自由落下の軌跡も一様にはならず、選別回収の精度が安定しないという問題点も生じていた。
本発明は、上記問題点を解消し、確実な選別回収が可能な回転ドラム型非磁性金属選別回収装置を提供することを目的とする。
【００１２】
上記目的を達成するために、本発明は、一方の端部に設けられた駆動ローラと、他方の端部に設けられた円筒状非磁性ドラムと、前記駆動ローラと前記ドラムに巻装された無端状のコンベアベルトと、前記ドラム内に回転自在に配置され、前記ドラムの内周面に近接して複数個の永久磁石が円筒磁性部材の円周方向に沿って固設された円筒状の永久磁石回転子とを有する回転ドラム型非磁性金属選別回収装置において、前記永久磁石は、磁化方向が前記ドラムの接線方向と略同一であり間隙をおいて配置された第一の磁石と、前記第一の磁石間の各間隙に配置され磁化方向が前記ドラムの法線方向と略同一の第二の磁石とで構成され、前記円筒磁性部材の断面形状を歯車状とし、前記円筒磁性部材の凹部の外周面上に前記第一の磁石を固定配置し、かつ前記円筒磁性部材の凸部に前記第二の磁石を固定配置し、前記第一の磁石の隣接する対向面は同極とし、かつ前記極間にある第二の磁石は前記ドラム側が前記極と同極となるように配置され、前記永久磁石回転子は前記コンベアベルトの進行方向と逆方向に回転される、という技術的手段を採用した。さらに本発明においては、前記第一の磁石の内周側の面に非磁性板を接着固定し、かつ前記第二の磁石の内周側磁極面に磁性板を接着固定して、両磁石部材を前記円筒磁性部材にボルトと接着剤を併用して固定しても良い。さらに本発明においては、前記円筒状非磁性ドラムの周囲に、磁気浮上させた導電性非磁性金属を気体噴射によって分離除去する除去手段を設けても良い。さらに本発明においては、前記円筒状非磁性ドラムの周囲に、磁気浮上させた導電性非磁性金属を羽根車状の回転部材によって分離除去する除去手段を設けても良い。
【００１３】
【発明の実施の形態】
図１は本発明の一実施例に係る回転ドラム型非磁性金属選別回収装置の概略断面図である。ただし、従来例と同一部分は同一の参照符号を付し、その詳細な説明は省略する。
本実施例の回転ドラム型非磁性金属選別回収装置の基本的構造は、図１１に示す従来例の構造と類似するが、ドラム１内部に回転自在に配設した永久磁石回転子４を特定の構造にしたことと、永久磁石回転子４の回転方向をコンベアベルト１０の進行方向と相対的に逆方向としたこと、すなわち従来例と逆方向の回転させる点で相違する。
【００１４】
まず本発明装置の全体構造について図１を用いて詳述する。無端状のコンベアベルト１０は、一方の端部を駆動ローラ９に、他方の端部を円筒状非磁性ドラム１に巻装されている。駆動ローラ９をモータ７によりＶベルト８を介して矢印ＲＲの方向に回転駆動することによって、コンベアベルト１０を矢印ＲＢの方向に走行させる機能を有している。
【００１５】
永久磁石回転子４は、モータ６によりＶベルト５を介して矢印ＲＭ方向、すなわち従来例である図１１とは反対となる時計方向に回転させる。この時、ドラム１はコンベアベルト１０と接触しているため矢印ＲＤ方向に回転する。従って、永久磁石回転子４の回転方向とドラム１の回転方向とは逆方向となる。
【００１６】
上記構成により、紙、布類、木片、合成樹脂等の非金属片１４および導電性非磁性金属片１５が混在した処理物は、ホッパー１３よりコンベアベルト１０上に供給されると、ＲＢ方向に搬送され永久磁石回転子４の上部領域に到達する。
処理物中の非金属片１４は磁石による磁気作用を受けないため、自重により自由落下して回収容器１８へ回収される。
【００１７】
一方、導電性非磁性金属片１５は永久磁石回転子４の上部領域に到達すると、永久磁石回転子４から磁気作用を受けてコンベアベルト１０の上方に浮上し、仕切板２４の所定の位置に設けられた回収孔２５を通過して仕切板２４の上面に現出する。
仕切板２４の上面に出た導電性非磁性金属片１５は、例えば図６または図７に示すような手段により、仕切板２４に沿って下方に搬送されることによって分離除去される。なお、図６および図７では、第一の磁石を省略している。
図６は、浮上した導電性非磁性金属片１５が、空気噴射装置２０から噴射される空気（これ以外の気体でも良い）によって分離除去される例を示す。図７は、浮上した導電性非磁性金属片１５が、羽根車２６によって分離除去される例を示す。なお、羽根車２６の代わりに他の回転部材（例えばブラシ）を使用しても良い。
【００１８】
次に本発明の永久磁石回転子の構造を図２により詳述する。図２に本実施例の永久磁石回転子４の１／４断面図を示す。円筒磁性部材３の円周方向に沿って、磁化方向がドラム１の接線方向と略同一の第一の磁石１６、１６´を間隙をおいて配置し、磁化方向がドラム１の法線方向と略同一の第二の磁石１７、１７´を第一の磁石１６、１６´間の各間隙に配置する。
また第一の磁石１６、１６´の隣接する対向面は同極とし、第二の磁石１７、１７´はドラム１側が隣接する第一の磁石１６、１６´と同極となるように配置する。すなわち図２において、第一の磁石１６は第二の磁石１７側がＮ極、第二の磁石１７´側がＳ極で、第一の磁石１６´も第二の磁石１７´側がＳ極となるように磁化されている。さらに、第二の磁石１７はドラム１側がＮ極で、第二の磁石１７´はドラム１側がＳ極となるように磁化されている。
【００１９】
上記の磁石配置によれば、第二の磁石のＮ極から発生した磁束は、ドラム１を貫通して当該磁石に隣接する第二の磁石のＳ極に流入する。ここで第二の磁石１７、１７´に注目すると、両磁石の間には図示の如く磁化された第一の磁石１６が存在するので、第二の磁石１７のＮ極とＳ極との間で短絡する磁束を実質的になくすことができる。従って、第二の磁石１７から発生する磁束を有効に外部に取り出すことが可能となり、もってドラム１表面の磁束密度を向上させることができる。
【００２０】
図２は第一の磁石１６、１６´の等角度間隔を３０°とした場合を示し、その場合のドラム１の外表面の法線方向の磁束密度分布を図３に示す。図３において縦軸は磁束密度Ｂ、横軸はＸ軸から反時計方向の角度θを示す。角度θが１５°以上になると周期的に同様な磁束密度曲線を描くため、角度θは０°〜１５°の範囲で示す。
【００２１】
磁束密度について従来例（図１４）と比較すると、従来例では磁束密度Ｂの最大値（絶対値）は３６００Ｇであるのに対し、本実施例（図３）では４９００Ｇと約１．３６倍の数値となり、ドラム１の外表面の磁束密度が向上していることが明らかである。
【００２２】
図２および図１３において、Ｈは非磁性金属片が受ける遠心方向の斥力ベクトル、Ｖはドラムの回転による接線方向の速度ベクトル、Ｆは斥力ベクトルＨと速度ベクトルＶとの合成ベクトルを示す。
同一条件での渦電流の発生による斥力の大きさは、対象物に作用する磁束密度の二乗に比例する。すなわち、本実施例において第一の磁石１６、１６´により発生する高周波交番磁界は、従来例において磁石２、２´により発生する高周波交番磁界の約１．３６倍の大きさとなり、非磁性金属片が受ける遠心方向の斥力ベクトルＨの大きさは約１．８倍となる。従って、導電性非磁性金属片が小口径になってもより確実な選別回収が可能となる。
【００２３】
次に、本発明において、永久磁石回転子４の回転方向をコンベアベルト１０の進行方向と相対的に逆方向とした理由について、図４および図５を用いて説明する。
【００２４】
図４に従来例の状態、すなわち永久磁石回転子４の回転方向ＲＭとコンベアベルト１０の進行方向と相対的に同一方向である状態を示す。
図４では、コンベアベルト１０の進行方向ＲＢと同方向の搬送力ＦＢと、永久磁石回転子４の電磁誘導から説明される斥力ＦＭとの合力ＦＴが作用するため、導電性非磁性金属片１５は永久磁石回転子４の前方方向に飛翔する。従って従来は、導電性非磁性金属片１５を永久磁石回転子４の前方に、できるだけ遠方に飛翔させることによって、選別精度の向上を図っている。
【００２５】
図５に本発明の状態、すなわち永久磁石回転子４の回転方向ＲＭとコンベアベルト１０の進行方向と相対的に逆方向である状態を示す。なお図５では、第一の磁石を省略してある。
図５の場合も図４と同様に、コンベアベルト１０の進行方向ＲＢと同方向の搬送力ＦＢと、永久磁石回転子４の電磁誘導から説明される斥力ＦＭとの合力ＦＴが作用するが、斥力ＦＭは搬送力ＦＢとは逆向きになり、上向きの合力ＦＴが発生するため、導電性非磁性金属片１５は永久磁石回転子４の鉛直上方方向に浮上する。
【００２６】
上記により、導電性非磁性金属片１５が永久磁石回転子４の鉛直上方方向に浮上する距離は、永久磁石回転子４の回転方向がコンベアベルト１０の進行方向と相対的に逆方向、すなわち図５の状態の方が従来例の図４の状態よりも大きいことが判る。本発明はコンベアベルトの鉛直上方方向に磁気浮上した導電性非磁性金属片を除去する方式を採用しているため、図５の方式がより適していることは容易に理解できる。
【００２７】
図８に他の実施例の永久磁石回転子４の１／４断面図を示す。図８において、円筒磁性部材３の断面形状を歯車状とし、円筒磁性部材３の凹部の外周面上に第一の磁石１６、１６’を配置し、円筒磁性部材３の凸部の外周面上に第二の磁石１７、１７’を配置する。第一の磁石１６、１６’および第二の磁石１７、１７’は、磁化方向が前述の実施例と同様になるように配置する。
【００２８】
図８に示す構成を採用することにより、第二の磁石１７、１７’は歯車状の円筒磁性部材３の凸部にて磁気回路を構成する（外部磁界を発生する）ため、有効磁路長が大きくなり、磁石動作点が高くなる。さらに第一の磁石１６、１６’の反発力との相互作用により、高効率の磁石ドラムを得ることができる。
【００２９】
図８は第一の磁石１６、１６´の等角度間隔を３０°とした場合を示し、その場合のドラム１の外表面の法線方向の磁束密度分布を図９に示す。図９において縦軸は磁束密度Ｂ、横軸はＸ軸から反時計方向の角度θを示す。角度θが１５°以上になると周期的に同様な磁束密度曲線を描くため、角度θは０°〜１５°の範囲で示す。
【００３０】
磁束密度について従来例（図１４）と比較すると、従来例では磁束密度Ｂの最大値（絶対値）は３６００Ｇであるのに対し、本実施例（図９）では５８００Ｇと約１．６倍の数値となり、ドラム１の外表面の磁束密度が大幅に向上していることが明らかである。
また、非磁性金属片が受ける遠心方向の斥力ベクトルＨの大きさは約２．５倍となるため、導電性非磁性金属片が小口径になっても、さらにより確実な選別回収が可能となる。
【００３１】
図１０に組立性を考慮した永久磁石回転子４の構造を示す。なお、図８と同一部分については同一の参照符号を付し、その詳細な説明は省略する。
図１０における永久磁石回転子４は、第一の磁石１６、１６´を接着固定した非磁性板２１と第二の磁石１７、１７´を接着固定した磁性板２２を、それぞれボルト２３により円筒磁性部材３に固定した構造を採用している。すなわち、接着固定と機械的固定を併用した構成である。
上記の構成を採用することにより、磁力による反発力があっても機械的に強制固定が可能なため組立性が向上し、作業時間の短縮等によるコスト低減が実現できる。
【００３２】
図１に示す本発明に係る装置と、図１１に示す従来の装置をそれぞれ製作し、導電性非磁性金属片の選別回収効率を比較した結果について以下に記述する。
図１に示す本発明に係る装置の、各部の主要寸法、材質および仕様は以下の通りである。
ドラム１：φ２００×３００mm、ＦＲＰ

駆動ローラ９−ドラム１間距離：６００mm
コンベアベルト１０の有効幅：２４０mm
コンベアベルト１０の表面移動速度：５１ｍ／ｍｉｎ
また従来の装置は、永久磁石回転子４の構造および回転方向以外は、本発明に係る装置と同様の構成である。
【００３３】
比較試験に供した処理物は、概略形状φ５×１０mmの樹脂ペレット５０００cm₃に、φ１０×０．５mmのアルミ片１００枚を混入したものとし、コンベアベルト１０への供給は振動フィーダを用いて、繰返し試験を行なった。比較試験結果を表１および表２に示す。
【００３４】
【表１】

【００３５】
【表２】

【００３６】
表１および表２より平均回収率を比較すると、従来の装置が４０．８％であるのに対し、本発明に係る装置は８４．８％（空気噴射）および８７．８％（羽根車）といずれも高い値を示している。従って、小口径の導電性非磁性金属片の選別回収は、従来のものに比べて本発明に係る装置の方が格段に優れていることが明らかである。
【００３７】
【発明の効果】
本発明は上記のような構成および作用を有するので、従来公知の回転ドラム型非磁性金属選別回収装置における問題点を解決し、特に処理物中に混在する小口径の導電性非磁性金属片を精度良く確実に選別回収することができる。
【図面の簡単な説明】
【図１】本発明の一実施例に係る選別回収装置の概略断面図である。
【図２】本発明の一実施例に係る選別回収装置の永久磁石回転子の１／４断面を示す図である。
【図３】図２の永久磁石回転子を採用した選別回収装置における磁束密度分布である。
【図４】従来の選別回収装置の導電性非磁性金属片に作用する力を説明するための図である。
【図５】本発明の一実施例に係る選別回収装置の導電性非磁性金属片に作用する力を説明するための図である。
【図６】本発明の一実施例に係る分離除去手段を示す図である。
【図７】本発明の他の実施例に係る分離除去手段を示す図である。
【図８】本発明の他の実施例に係る選別回収装置の永久磁石回転子の１／４断面を示す図である。
【図９】図８の永久磁石回転子を採用した選別回収装置における磁束密度分布である。
【図１０】本発明の他の実施例に係る選別回収装置の永久磁石回転子の１／４断面を示す図である。
【図１１】従来の選別回収装置の概略断面図である。
【図１２】図１１の要部拡大図である。
【図１３】従来の選別回収装置の永久磁石回転子の１／４断面を示す図である。
【図１４】従来の選別回収装置における磁束密度分布である。
【符号の説明】
１…ドラム、２、２´…磁石、３…円筒磁性部材、４…永久磁石回転子、
５、８…Ｖベルト、６、７…モータ、９…駆動ローラ、
１０…コンベアベルト、１３…ホッパ、１４…非金属片、
１５…導電性非磁性金属片、１６、１６´…第一の磁石、
１７、１７´…第二の磁石、１８、１９…回収容器、２０…空気噴射装置、
２１…非磁性板、２２…磁性板、２３…ボルト、
２４…仕切板、２５…回収孔、２６…羽根車[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotating drum type nonmagnetic metal sorting and collecting apparatus for separating and collecting conductive nonmagnetic metals such as aluminum and copper from a processed material, and particularly for collecting small diameter conductive nonmagnetic metal pieces. The present invention relates to a rotating drum type nonmagnetic metal sorting and collecting apparatus.
[0002]
[Prior art]
In recent years, as environmental problems are attracting attention, the reuse of resources is also progressing, and from daily waste, not only iron but also non-ferrous metals, paper, cloth, wood chips, synthetic resin, rubber, glass, etc. Resource recovery is performed in a wide range, and new technology is also adopted in the recovery system.
An apparatus for sorting and collecting non-magnetic light metals represented by aluminum among non-ferrous metals is often used for collecting and reusing aluminum cans in municipal waste or aluminum contained in cut scraps of scrapped automobiles.
As a means of sorting and collecting non-ferrous metals with other wastes, magnetic motors have been conventionally used as a linear motor type applying a moving AC magnetic field, an inside drum type having a permanent magnet disposed on the outer periphery of a rotary kiln-like rotating cylinder, Numerous structures such as a sliding separator type with permanent magnets arranged under a smooth slope, or a rotating drum type with a drum wound around a conveyor belt and a permanent magnet rotor inside Has been proposed.
[0003]
Of these, the rotary drum type is most frequently used, and a conventional example is shown in FIG. In FIG. 11, the endless conveyor belt 10 is wound around the driving roller 9 at one end and around the drum 1 at the other end. The drive roller 9 is driven to rotate in the direction of arrow RR by the motor 7 via the V-belt 8, thereby causing the conveyor belt 10 to travel in the direction of arrow RB. Accordingly, the drum 1 as the driven roller rotates in the direction indicated by the arrow RD. The drum 1 is made of a nonmagnetic material, and a permanent magnet rotor 4 is disposed in the drum 1 so as to be concentric with the drum 1 so as to be rotatable.
[0004]
Next, the configuration of the permanent magnet rotor 4 is shown in FIG. The magnet 2 and the magnet 2 ′ are arranged on the outer peripheral surface of the cylindrical magnetic member 3 such that the N pole and the S pole are alternately positioned on the drum 1 side at equal angular intervals along the circumferential direction, and the outer surfaces thereof are The drum 1 is fixed so as to be close to the inner peripheral surface of the drum 1. The permanent magnet rotor 4 is concentric with the drum 1 and rotates in the same direction RM as the rotation direction RD. However, the permanent magnet rotor 4 is rotated by another motor 6 via the V-belt 5 so that the rotation speed (peripheral speed) is different. It has a heavy structure. The rotational speed of the permanent magnet rotor 4 is set to be sufficiently higher than the rotational speed of the drum 1.
[0005]
Thus, the magnetic flux C flowing out from the N pole of the magnet 2 passes through the drum 1 and the conveyor belt 10 wound on the drum 1 and flows into the S pole of the magnet 2 ′. Therefore, a strong magnetic field is generated and various influences are given to the processed object (14 or 15). Further, containers 18 and 19 for collecting processed materials that fall from the conveyor belt 10 and are collected are disposed on the lower front side of the drum 1, and the containers 18 are made of non-metal such as paper, cloth, wood pieces, synthetic resin, or the like. In the pieces 14 and 19, conductive nonmagnetic metal pieces 15 such as aluminum and copper are respectively collected.
[0006]
The operation of the rotating drum type nonmagnetic metal sorting and collecting apparatus is as follows.
First, when a processed product in which the conductive nonmagnetic metal piece 15 and the nonmetal piece 14 are mixed is introduced from the upper end open portion of the hopper 13, it falls onto the surface of the conveyor belt 10 and the central axis of the drum 1 as the conveyor belt 10 travels. To the upper region of the vertical line passing through, i.e. the top. Here, the processed material on the conveyor belt 10 has a certain thickness and is layered, but is shown in a scattered state in FIG. 11 for easy understanding.
[0007]
When the processed material reaches the top of the drum 1, it is generated by the magnet 2 and the magnet 2 ′ fixed on the outer peripheral surface of the cylindrical magnetic member 3 by the high-speed rotation of the permanent magnet rotor 4 provided in the drum 1. Passes through a high frequency alternating magnetic field. At this time, an eddy current described by Faraday electromagnetic induction is generated inside the conductive nonmagnetic metal piece 15, and the direction of the magnetic flux generated due to the eddy current and the permanent magnet rotor 4 are generated. Since the directions of the magnetic fluxes conflict with each other according to Lenz's law, a repulsive force (repulsive force) in the centrifugal direction is generated by the interaction between the two. Further, the conveying force of the conveyor belt 10 acts as a combined force, and the conductive nonmagnetic metal piece 15 flies forward and upward as viewed from the running direction of the conveyor belt 10, and is parabolic from almost the top of the drum 1. It falls along a trajectory a and is sorted and collected into the container 19.
[0008]
Further, since the non-metal piece 14 in the processed material does not receive any magnetic action of the magnet 2 and the magnet 2 ′, the non-metal piece 14 falls freely by its own weight and is sorted and collected into the container 18 along the locus of b.
[0009]
A quarter sectional view of a conventional permanent magnet rotor 4 is shown in FIG. FIG. 13 shows a case where the magnet 2 and the magnet 2 ′ are fixed on the outer peripheral surface of the cylindrical magnetic member 3 at an equal angular interval of 30 ° along the circumferential direction.
The demagnetizing field that runs inside the magnet in an attempt to weaken the magnetization of the magnet becomes smaller as the distance between the north and south poles increases. Therefore, in order to reduce the influence of the demagnetizing field and increase the magnetism of the magnet, the member for fixing the magnet is formed of a magnetic material such as iron, and the magnetic circuit of the adjacent magnet is connected to connect the N pole in the magnet. It is generally known that the distance between the S pole and the S pole may be increased.
In FIG. 13, when the angle in the counterclockwise direction is θ, the relationship (magnetic flux density distribution) between the magnetic flux density B in the normal direction of the outer surface of the drum 1 and the angle θ is as shown in FIG. In addition, since the same magnetic flux density curve is drawn periodically when angle (theta) becomes 15 degrees or more, angle (theta) is shown in the range of 0 degrees-15 degrees.
[0010]
Generally, the repulsive force F which a conductive nonmagnetic metal piece receives from a permanent magnet rotor is represented by the following formula.
F∝Bg ² × f × σ × A / ρ (1)
Where Bg: magnetic flux density f: frequency (= number of magnet drum poles × number of magnet drum rotations)
σ: Conductivity A: Surface area of processed material ρ: When the conductive nonmagnetic metal piece 15 that is the target of density sorting and recovery has a small diameter, the surface area becomes smaller and the repulsive force F becomes smaller from the equation (1). it can.
[0011]
[Problems to be solved by the invention]
In the conventional rotating drum type nonmagnetic metal sorting and collecting device, when the conductive nonmagnetic metal piece has a small diameter, the repulsive force received from the permanent magnet rotor is reduced, and it is difficult to reliably sort and collect. .
Further, since the shape of the conductive non-magnetic metal piece is not uniform, the locus of free fall is not uniform due to air resistance or the like, and there is a problem that the accuracy of sorting and collecting is not stable.
An object of the present invention is to provide a rotating drum type non-magnetic metal sorting and collecting apparatus capable of solving the above-mentioned problems and performing reliable sorting and collecting.
[0012]
In order to achieve the above object, the present invention comprises a driving roller provided at one end, a cylindrical nonmagnetic drum provided at the other end, and the driving roller and the drum wound around the driving roller. An endless conveyor belt, a cylindrical belt that is rotatably disposed in the drum and has a plurality of permanent magnets fixed along the circumferential direction of the cylindrical magnetic member in the vicinity of the inner peripheral surface of the drum. In the rotating drum type non-magnetic metal sorting and collecting apparatus having a permanent magnet rotor, the permanent magnet has a magnetization direction substantially the same as a tangential direction of the drum, and a first magnet arranged with a gap therebetween, A second magnet disposed in each gap between the first magnets and having a magnetization direction substantially the same as a normal direction of the drum, and the cylindrical magnetic member has a gear-like cross-sectional shape; The first magnet is fixedly arranged on the outer peripheral surface of the recess. And the second magnet is fixedly disposed on the convex portion of the cylindrical magnetic member, the adjacent opposing surfaces of the first magnet have the same pole, and the second magnet between the poles is on the drum side. The technical means was adopted that the permanent magnet rotor is arranged in the same polarity as the pole, and the permanent magnet rotor is rotated in the direction opposite to the traveling direction of the conveyor belt. Further, in the present invention, the first non-magnetic plate on the surface of the inner peripheral side of the magnet is bonded and fixed, and a magnetic plate bonded and fixed to the inner peripheral side magnetic pole surface of the second magnet, the magnets member May be fixed to the cylindrical magnetic member by using a bolt and an adhesive together. Further, in the present invention, a removing means for separating and removing the magnetically levitated conductive nonmagnetic metal by gas injection may be provided around the cylindrical nonmagnetic drum. Further, in the present invention, a removing means for separating and removing the magnetically levitated conductive nonmagnetic metal by an impeller-like rotating member may be provided around the cylindrical nonmagnetic drum.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic sectional view of a rotating drum type nonmagnetic metal sorting and collecting apparatus according to an embodiment of the present invention. However, the same parts as those of the conventional example are denoted by the same reference numerals, and detailed description thereof is omitted.
The basic structure of the rotating drum type nonmagnetic metal sorting and collecting apparatus of this embodiment is similar to the structure of the conventional example shown in FIG. 11, but a permanent magnet rotor 4 rotatably disposed inside the drum 1 is specified. The difference is that the structure is different from that in which the rotation direction of the permanent magnet rotor 4 is set in the direction opposite to the traveling direction of the conveyor belt 10, that is, in the direction opposite to the conventional example.
[0014]
First, the overall structure of the device of the present invention will be described in detail with reference to FIG. The endless conveyor belt 10 has one end wound around the driving roller 9 and the other end wound around the cylindrical nonmagnetic drum 1. The drive roller 9 is driven to rotate in the direction of the arrow RR by the motor 7 via the V-belt 8, thereby causing the conveyor belt 10 to travel in the direction of the arrow RB.
[0015]
The permanent magnet rotor 4 is rotated by the motor 6 via the V belt 5 in the direction of the arrow RM, that is, in the clockwise direction opposite to that in FIG. At this time, since the drum 1 is in contact with the conveyor belt 10, it rotates in the direction of the arrow RD. Therefore, the rotation direction of the permanent magnet rotor 4 is opposite to the rotation direction of the drum 1.
[0016]
With the above configuration, when a non-metal piece 14 such as paper, cloth, wood pieces, and synthetic resin and a conductive non-magnetic metal piece 15 are mixed and supplied to the conveyor belt 10 from the hopper 13, It is conveyed and reaches the upper region of the permanent magnet rotor 4.
Since the non-metal piece 14 in the processed material is not subjected to the magnetic action by the magnet, it falls freely by its own weight and is collected in the collection container 18.
[0017]
On the other hand, when the conductive nonmagnetic metal piece 15 reaches the upper region of the permanent magnet rotor 4, it receives a magnetic action from the permanent magnet rotor 4 and floats above the conveyor belt 10, and reaches a predetermined position on the partition plate 24. It passes through the provided recovery hole 25 and appears on the upper surface of the partition plate 24.
The conductive non-magnetic metal piece 15 protruding on the upper surface of the partition plate 24 is separated and removed by being conveyed downward along the partition plate 24 by means such as shown in FIG. 6 or FIG. In FIGS. 6 and 7, the first magnet is omitted.
FIG. 6 shows an example in which the levitated conductive nonmagnetic metal piece 15 is separated and removed by air (other gas may be used) injected from the air injection device 20. FIG. 7 shows an example in which the levitated conductive nonmagnetic metal piece 15 is separated and removed by the impeller 26. Note that another rotating member (for example, a brush) may be used instead of the impeller 26.
[0018]
Next, the structure of the permanent magnet rotor of the present invention will be described in detail with reference to FIG. FIG. 2 shows a quarter cross-sectional view of the permanent magnet rotor 4 of this embodiment. Along the circumferential direction of the cylindrical magnetic member 3,

first magnets

16 and 16 ′ whose magnetization direction is substantially the same as the tangential direction of the drum 1 are arranged with a gap therebetween, and the magnetization direction is the normal direction of the drum 1. Substantially identical second magnets 17 and 17 'are arranged in the gaps between the first magnets 16 and 16'.
Moreover, the adjacent opposing surfaces of the first magnets 16 and 16 'have the same polarity, and the second magnets 17 and 17' are arranged so that the drum 1 side has the same polarity as the adjacent first magnets 16 and 16 '. . That is, in FIG. 2, the first magnet 16 has an N pole on the second magnet 17 side, an S pole on the second magnet 17 'side, and the first magnet 16' has an S pole on the second magnet 17 'side. Is magnetized. Further, the second magnet 17 is magnetized so that the drum 1 side has an N pole, and the second magnet 17 'has the drum 1 side an S pole.
[0019]
According to the above magnet arrangement, the magnetic flux generated from the N pole of the second magnet flows through the drum 1 and flows into the S pole of the second magnet adjacent to the magnet. Here, when attention is paid to the

second magnets

17 and 17 ′, the first magnet 16 magnetized as shown in the drawing exists between the two magnets, and therefore, between the N pole and the S pole of the second magnet 17. The magnetic flux that is short-circuited can be substantially eliminated. Therefore, it is possible to effectively extract the magnetic flux generated from the second magnet 17 to the outside, thereby improving the magnetic flux density on the surface of the drum 1.
[0020]
FIG. 2 shows the case where the equiangular interval between the

first magnets

16 and 16 ′ is 30 °, and FIG. 3 shows the magnetic flux density distribution in the normal direction of the outer surface of the drum 1 in that case. In FIG. 3, the vertical axis indicates the magnetic flux density B, and the horizontal axis indicates the angle θ counterclockwise from the X axis. Since the same magnetic flux density curve is periodically drawn when the angle θ is 15 ° or more, the angle θ is shown in the range of 0 ° to 15 °.
[0021]
Compared with the conventional example (FIG. 14) regarding the magnetic flux density, the maximum value (absolute value) of the magnetic flux density B is 3600G in the conventional example, whereas in this example (FIG. 3), it is about 1.36 times that of 4900G. It is clear that the magnetic flux density on the outer surface of the drum 1 is improved.
[0022]
2 and 13, H is a repulsive force vector in the centrifugal direction received by the nonmagnetic metal piece, V is a velocity vector in the tangential direction due to rotation of the drum, and F is a combined vector of the repulsive force vector H and the velocity vector V.
The magnitude of the repulsive force due to the generation of eddy current under the same conditions is proportional to the square of the magnetic flux density acting on the object. That is, the high-frequency alternating magnetic field generated by the first magnets 16 and 16 'in this embodiment is about 1.36 times the high-frequency alternating magnetic field generated by the magnets 2 and 2' in the conventional example. The magnitude of the repulsive force vector H in the centrifugal direction received by the piece is about 1.8 times. Accordingly, even when the conductive nonmagnetic metal piece has a small diameter, more reliable sorting and collection can be performed.
[0023]
Next, in the present invention, the reason why the rotation direction of the permanent magnet rotor 4 is set in the direction opposite to the traveling direction of the conveyor belt 10 will be described with reference to FIGS. 4 and 5.
[0024]
FIG. 4 shows a state of a conventional example, that is, a state in which the rotational direction RM of the permanent magnet rotor 4 and the traveling direction of the conveyor belt 10 are relatively in the same direction.
In FIG. 4, a resultant force FT of the conveying force FB in the same direction as the traveling direction RB of the conveyor belt 10 and the repulsive force FM explained from the electromagnetic induction of the permanent magnet rotor 4 acts. Fly in the forward direction of the permanent magnet rotor 4. Therefore, conventionally, the conductive nonmagnetic metal piece 15 is made to fly as far as possible in front of the permanent magnet rotor 4 to improve the sorting accuracy.
[0025]
FIG. 5 shows a state of the present invention, that is, a state in which the rotation direction RM of the permanent magnet rotor 4 and the traveling direction of the conveyor belt 10 are opposite to each other. In FIG. 5, the first magnet is omitted.
In the case of FIG. 5 as well, the resultant force FT of the conveying force FB in the same direction as the traveling direction RB of the conveyor belt 10 and the repulsive force FM explained from the electromagnetic induction of the permanent magnet rotor 4 acts as in FIG. The repulsive force FM is opposite to the conveying force FB, and an upward resultant force FT is generated, so that the conductive nonmagnetic metal piece 15 floats vertically upward of the permanent magnet rotor 4.
[0026]
As described above, the distance that the conductive nonmagnetic metal piece 15 floats in the vertical upward direction of the permanent magnet rotor 4 is such that the rotation direction of the permanent magnet rotor 4 is relatively opposite to the traveling direction of the conveyor belt 10, that is, It can be seen that the state of 5 is larger than the state of FIG. 4 of the conventional example. Since the present invention employs a method of removing the conductive nonmagnetic metal pieces magnetically levitated vertically above the conveyor belt, it can be easily understood that the method of FIG. 5 is more suitable.
[0027]
FIG. 8 shows a quarter cross-sectional view of a permanent magnet rotor 4 of another embodiment. In FIG. 8, the cylindrical magnetic member 3 has a gear-like cross-sectional shape, the

first magnets

16 and 16 ′ are arranged on the outer peripheral surface of the concave portion of the cylindrical magnetic member 3, and the outer peripheral surface of the convex portion of the cylindrical magnetic member 3. The second magnets 17 and 17 'are arranged in the above. The

first magnets

16 and 16 ′ and the

second magnets

17 and 17 ′ are arranged so that the magnetization directions are the same as those in the above-described embodiment.
[0028]
By adopting the configuration shown in FIG. 8, the

second magnets

17 and 17 ′ form a magnetic circuit (generates an external magnetic field) with the convex portions of the gear-shaped cylindrical magnetic member 3, so that the effective magnetic path length Increases and the magnet operating point increases. Furthermore, a highly efficient magnet drum can be obtained by interaction with the repulsive force of the first magnets 16 and 16 '.
[0029]
FIG. 8 shows the case where the equiangular interval between the

first magnets

16 and 16 ′ is 30 °, and FIG. 9 shows the magnetic flux density distribution in the normal direction of the outer surface of the drum 1 in that case. In FIG. 9, the vertical axis indicates the magnetic flux density B, and the horizontal axis indicates the angle θ counterclockwise from the X axis. Since the same magnetic flux density curve is periodically drawn when the angle θ is 15 ° or more, the angle θ is shown in the range of 0 ° to 15 °.
[0030]
Compared with the conventional example (FIG. 14) regarding the magnetic flux density, the maximum value (absolute value) of the magnetic flux density B is 3600G in the conventional example, whereas this example (FIG. 9) is about 1.6 times as large as 5800G. It is clear that the magnetic flux density on the outer surface of the drum 1 is greatly improved.
In addition, since the magnitude of the repulsive force vector H in the centrifugal direction received by the nonmagnetic metal piece is about 2.5 times, even more reliable sorting and collection is possible even when the conductive nonmagnetic metal piece has a small diameter. Become.
[0031]
FIG. 10 shows the structure of the permanent magnet rotor 4 in consideration of assemblability. The same parts as those in FIG. 8 are denoted by the same reference numerals, and detailed description thereof is omitted.
The permanent magnet rotor 4 shown in FIG. 10 includes a nonmagnetic plate 21 to which the

first magnets

16 and 16 ′ are bonded and a magnetic plate 22 to which the

second magnets

17 and 17 ′ are bonded and fixed to each other by a bolt 23. A structure fixed to the member 3 is adopted. That is, it is the structure which used adhesion fixation and mechanical fixation together.
By adopting the above configuration, even if there is a repulsive force due to magnetic force, it can be mechanically forcibly fixed, so that the assemblability is improved and the cost can be reduced by shortening the working time.
[0032]
The device according to the present invention shown in FIG. 1 and the conventional device shown in FIG. 11 are manufactured, and the results of comparing the sorting and collection efficiency of the conductive nonmagnetic metal pieces are described below.
The main dimensions, materials and specifications of each part of the apparatus according to the present invention shown in FIG. 1 are as follows.
Drum 1: φ200 × 300mm, FRP

Distance between drive roller 9 and drum 1: 600 mm
Effective width of conveyor belt 10: 240 mm
Surface moving speed of conveyor belt 10: 51 m / min
The conventional apparatus has the same configuration as the apparatus according to the present invention except for the structure of the permanent magnet rotor 4 and the rotation direction.
[0033]
The processed material subjected to the comparative test is a mixture of resin pellets 5000 cm ₃ having a general shape of φ5 × 10 mm and 100 pieces of aluminum pieces of φ10 × 0.5 mm mixed, and the supply to the conveyor belt 10 is performed using a vibration feeder. Repeated tests were conducted. The comparative test results are shown in Tables 1 and 2.
[0034]
[Table 1]

[0035]
[Table 2]

[0036]
Comparing the average recovery rates from Tables 1 and 2, the conventional apparatus is 40.8%, whereas the apparatus according to the present invention is 84.8% (air injection) and 87.8% (impeller). Both show high values. Therefore, it is clear that the apparatus according to the present invention is far superior in sorting and collecting small-diameter conductive nonmagnetic metal pieces compared to the conventional one.
[0037]
【The invention's effect】
Since the present invention has the above-described configuration and operation, it solves the problems in the conventionally known rotary drum type non-magnetic metal sorting and collecting apparatus, and in particular, a small-diameter conductive non-magnetic metal piece mixed in the processed material. Sorting and collecting can be performed accurately and reliably.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a sorting and collecting apparatus according to an embodiment of the present invention.
FIG. 2 is a view showing a quarter cross section of a permanent magnet rotor of a sorting and collecting apparatus according to an embodiment of the present invention.
FIG. 3 is a magnetic flux density distribution in a sorting and collecting apparatus employing the permanent magnet rotor of FIG.
FIG. 4 is a diagram for explaining a force acting on a conductive nonmagnetic metal piece of a conventional sorting and collecting apparatus.
FIG. 5 is a diagram for explaining a force acting on a conductive nonmagnetic metal piece of a sorting and collecting apparatus according to an embodiment of the present invention.
FIG. 6 is a diagram showing separation / removal means according to an embodiment of the present invention.
FIG. 7 is a diagram showing separation / removal means according to another embodiment of the present invention.
FIG. 8 is a view showing a quarter cross section of a permanent magnet rotor of a sorting and collecting apparatus according to another embodiment of the present invention.
FIG. 9 is a magnetic flux density distribution in a sorting and collecting apparatus employing the permanent magnet rotor of FIG.
FIG. 10 is a view showing a quarter cross section of a permanent magnet rotor of a sorting and collecting apparatus according to another embodiment of the present invention.
FIG. 11 is a schematic sectional view of a conventional sorting and collecting apparatus.
12 is an enlarged view of a main part of FIG. 11. FIG.
FIG. 13 is a view showing a quarter cross section of a permanent magnet rotor of a conventional sorting and collecting apparatus.
FIG. 14 is a magnetic flux density distribution in a conventional sorting and collecting apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Drum 2, 2 '... Magnet, 3 ... Cylindrical magnetic member, 4 ... Permanent magnet rotor,
5, 8 ... V belt, 6, 7 ... motor, 9 ... drive roller,
10 ... conveyor belt, 13 ... hopper, 14 ... non-metal piece,
15 ... conductive non-magnetic metal piece, 16, 16 '... first magnet,
17, 17 '... second magnet, 18, 19 ... recovery container, 20 ... air injection device,
21 ... Non-magnetic plate, 22 ... Magnetic plate, 23 ... Bolt,
24 ... partition plate, 25 ... recovery hole, 26 ... impeller

Claims

A driving roller provided at one end, a cylindrical non-magnetic drum provided at the other end, an endless conveyor belt wound around the driving roller and the drum, and rotating in the drum A rotating drum type non-magnetic having a cylindrical permanent magnet rotor, which is arranged freely and has a plurality of permanent magnets fixed in the circumferential direction of the cylindrical magnetic member in the vicinity of the inner peripheral surface of the drum In the metal sorting and collecting apparatus, the permanent magnet has a magnetization direction substantially the same as a tangential direction of the drum and is arranged in each gap between the first magnet and a first magnet arranged with a gap therebetween. The cylindrical magnet is made of a second magnet whose direction is substantially the same as the normal direction of the drum. It is fixedly placed, and the front of the convex part of the cylindrical magnetic member The second magnet is fixedly arranged, the adjacent opposing surfaces of the first magnet have the same polarity, and the second magnet located between the poles is arranged so that the drum side has the same polarity as the pole, The rotating drum type non-magnetic metal sorting and collecting apparatus, wherein the permanent magnet rotor is rotated in a direction opposite to a traveling direction of the conveyor belt.

Said first non-magnetic plate on the surface of the inner peripheral side of the magnet is bonded and fixed, and a magnetic plate bonded and fixed to the inner peripheral side magnetic pole surface of the second magnet, the two magnets member to the cylindrical magnetic member The rotating drum type nonmagnetic metal sorting and collecting apparatus according to claim 1, wherein the bolt and the adhesive are used together and fixed.

The rotary drum type nonmagnetic metal sorting according to claim 1 or 2, wherein a removing means for separating and removing the magnetically levitated conductive nonmagnetic metal by gas injection is provided around the cylindrical nonmagnetic drum. Recovery device.

The rotating drum type according to claim 1 or 2, wherein a removing means for separating and removing the electrically conductive nonmagnetic metal magnetically levitated by an impeller-like rotating member is provided around the cylindrical nonmagnetic drum. Non-magnetic metal sorting and collecting device.