JP3649121B2

JP3649121B2 - Metal cleaning equipment

Info

Publication number: JP3649121B2
Application number: JP2000380303A
Authority: JP
Inventors: 典昭末藤; 健治馬立; 政治菅; 清文渋谷; 昭浩永廣; 誠二佐藤
Original assignee: JFE Steel Corp
Current assignee: JFE Steel Corp
Priority date: 1999-12-14
Filing date: 2000-12-14
Publication date: 2005-05-18
Anticipated expiration: 2020-12-14
Also published as: JP2001234377A

Description

【０００１】
【発明の属する技術分野】
本発明は、鋼帯等の金属材の洗浄設備に関するもので、洗浄時に発生する泡を消泡し、消泡によって生じた液を洗浄液として再利用することができるようにした設備に関するものである。
【０００２】
【従来の技術】
一般的に鋼帯等の洗浄設備においては、苛性ソーダ、オルソケイ酸ソ−ダ等のアルカリ水溶液等を洗浄液として用い、洗浄液に鋼帯等を浸漬させる方法や、洗浄液を鋼帯等にスプレーする方法、また鋼帯等を洗浄液に浸漬させた状態または鋼帯等に洗浄液をスプレーした状態で電解する方法、さらには鋼帯等を洗浄液に浸漬させた状態または鋼帯等に洗浄液をスプレーした状態でブラッシングする方法等の組み合わせにより、鋼帯等の表面に付着している圧延油等を脱脂洗浄することが行われている。この脱脂洗浄においては、圧延油等とアルカリ水溶液等の洗浄液が化学反応を起こし、洗浄設備の洗浄タンク内または循環タンク内で多量の泡が発生し、タンク外に泡が溢れ出して洗浄液の損失を招く。このため洗浄液の補給が必要となり、洗浄液の購入費用によりコストを上昇させる。また、洗浄液は洗浄性確保のためしばしば常温から昇温して用いられるため、洗浄液の補給に伴い蒸気等の熱エネルギーを大量に消費する。また、泡がタンク外に溢れ出すことによって、タンク周囲の作業環境を著しく悪化させるとともに、廃液としての処理費用が必要となる。この泡の溢れ出しを防止する目的で、洗浄液中に消泡剤を投入することが一般的に行われるが、高価な消泡剤を多量かつ連続的に投入しなければならず、消泡剤の購入費用によりコストが上昇する。また、消泡剤を投入しても消泡が１００％とはならず、消泡対策の決め手にはならない。
【０００３】
このような問題を解決する装置が以下の公報に開示されている。特開平３−１５３８８７号公報には、発泡したアルカリ洗浄液を貯留槽に貯留し、貯留槽の上部に発生した泡をオ−バ−フロ−タンクに導き、オ−バ−フロ−タンク内の泡に対し霧状水を散布して消泡する装置が開示されている。また、特開平６−４９５４４号公報には、鋼帯の脱脂洗浄槽および洗浄液循環槽内に発生する泡沫に対して、５０℃〜３００℃の熱風を吹き付けて消泡する装置が開示されている。
【０００４】
一方、消泡液を洗浄液として再利用する装置が、特開平１１−３６０９０号公報に開示されている。これは、洗浄タンクで発生した泡をエジェクタ−で消泡箱に送り消泡し、消泡により生じた液を循環タンクに貯留し、貯留した液を洗浄液として循環ポンプで洗浄タンクに戻すものである。
【０００５】
【発明が解決しようとする課題】
しかしながら、特開平３−１５３８８７号装置のように、泡に対して霧状水を散布するものは、多量の散布水を必要とするため、消泡後の洗浄液の濃度が薄くなるという問題がある。また、霧状水を散布して消泡した洗浄液面に霧状水が衝突して発泡するために完全な消泡を行うことができない。このため、泡の発生が多い場合、オ−バ−フロ−タンクからの泡の溢れ出しを防止するには不十分であった。また、特開平６−４９５４４号装置のように、泡沫に対して熱風を吹き付けて消泡するものは、発泡に見合う消泡能力を維持するために多量の熱風が必要であり、しかも確実にかつ短時間に完全な消泡ができないという問題があった。
【０００６】
一方、特開平１１−３６０９０号装置では、発生した泡を従来よりも大量に排出し、排出した泡をほぼ１００％消泡することが可能であるが、油分や鉄粉等が混入している消泡後の液を、そのまま循環タンクに戻すため、時間の経過に伴い洗浄液の洗浄能力が低下してしまうという問題がある。
【０００７】
本発明は、発生する泡を効率良く消泡し、消泡によって生じた消泡液を洗浄液として再利用でき、しかも洗浄後の洗浄能力の低下を適切に防止できる金属材の洗浄設備を提供することを目的とする。
【０００８】
【課題を解決するための手段】
本発明の金属材の洗浄設備は以下のような特徴を有する。
【０００９】
（１）表面に油脂等が付着した金属材を洗浄するための洗浄タンクと、
該洗浄タンクとの間で洗浄液を循環させるための循環タンクと、
該循環タンク内の洗浄液の泡を吸引するための泡吸引手段と、
該泡吸引手段により吸引された泡が供給され、破泡がなされる消泡箱と、
該消泡箱での破泡により生じた液が供給され、該液中の不純物成分の分離除去を行う不純物分離タンクと、
該不純物分離タンクで不純物成分が分離除去された液を前記循環タンクに供給する配管系とを備えたことを特徴とする金属材の洗浄設備。
【００１０】
（２）循環タンクが、タンク内に貯留された洗浄液中に下部が没入する仕切壁を有し、該仕切壁により分けられた区画の一つに洗浄タンクからの洗浄液を受け入れるようにしたことを特徴とする上記（１）に記載の金属材の洗浄設備。
【００１１】
（３）不純物分離タンクが、タンク上部から垂設された複数の仕切り板と複数の堰により分けられた複数段の分離区画を有することを特徴とする上記（１）または（２）に記載の金属材の洗浄設備。
【００１２】
（４）泡吸引手段の泡吸い込み口が、循環タンク内の洗浄液の液面レベルに追従して上下方向に昇降することを特徴とする上記（１）乃至（３）のいずれかに記載の金属材の洗浄設備。
【００１３】
（５）分離区画を有する不純物分離タンクが、液の分離区画滞留時間が少なくとも１５分以上となるような実効容積を有することを特徴とする上記（３）または（４）のいずれかに記載の金属材の洗浄設備。
【００１４】
（６）分離区画を有する不純物分離タンクが、前記各分離区画毎において分離された不純物を、各分離区画毎にタンク外に排出するための排出手段を有することを特徴とする上記（３）乃至（５）のいずれかに記載の金属材の洗浄設備。
【００１５】
（７）泡吸引手段として蒸気エジェクターを用いることを特徴とする上記（１）乃至（６）のいずれかに記載の金属材の洗浄設備。
【００１６】
（８）表面に油脂等が付着した金属材を洗浄するための洗浄タンクと、該洗浄タンクとの間で洗浄液を循環させるための循環タンクと、前記洗浄タンク内の洗浄液の泡を吸引するための泡吸引手段と、該泡吸引手段により吸引された泡が供給され、破泡がなされる消泡箱と、該消泡箱での破泡により生じた液が供給され、該液中の不純物成分の分離除去を行う、タンク上部から垂設された複数の仕切り板と複数の堰により分けられた複数段の分離区画を有する不純物分離タンクと、該不純物分離タンクで不純物成分が分離除去された液を前記循環タンクに供給する配管系とを備えたことを特徴とする金属材の洗浄設備。
【００１７】
本発明においては、洗浄後の泡を消泡して得られる不純物を含んだ液（以下、「消泡液」という）を不純物分離タンクに通すことにより不純物を除去し、得られた液を回収洗浄液として循環タンクに戻すので、洗浄液の洗浄能力を長期間維持することができる。このことにより、洗浄液の補給量が低減できるので、洗浄液の購入費用を節減できる。また、洗浄液の補給量を低減できることにより、昇温に必要な蒸気等の熱エネルギーを節減できる。さらに、泡がタンク外に溢れ出すことを防止するため、タンク周囲の作業環境は改善されるとともに、廃液としての処理費用が不要となる。
【００１８】
以下の説明では、石鹸分とは、鋼帯表面に付着している圧延油が洗浄液中でアルカリにより加水分解（鹸化）反応することによって、生成される脂肪酸ナトリウムを指し、油分とは、圧延油中の前記鹸化反応を起こさない不鹸化油分と圧延油中の前記鹸化反応が不充分なため存在する未鹸化油分の総和を指し、鉄分とは主に鋼帯表面から生じる磨耗粉を指す。
【００１９】
【発明の実施の形態】
図１は、本発明の洗浄設備の一実施形態を示す概略図である。
【００２０】
図１は、表面に油脂等が付着した金属材を洗浄するための洗浄タンク２と、洗浄タンク２との間で洗浄液３を循環させるための循環タンク５と、循環タンク内の洗浄液３の泡を吸引するための泡吸引手段と、泡吸引手段により吸引された泡が供給され、破泡がなされる消泡箱１１と、消泡箱１１での破泡により生じた液が供給され、液中の不純物成分の分離除去を行う不純物分離タンク１５と、不純物分離タンク１５で不純物成分が分離除去された液を前記循環タンク５に供給する配管系２２、２４とを備えている。
【００２１】
前記洗浄タンク２は、表面に油脂等が付着した鋼帯等を洗浄するための洗浄液が入れられ、鋼帯１が連続通板している。
【００２２】
前記循環タンク５は、タンク内に貯留されている洗浄液３に下部を没入させた仕切壁６により、洗浄液上部空間が第１区画７および第２区画８に区分されている。そして、洗浄タンク２からの液が管４により第１区画７に供給される。
【００２３】
前記泡吸引手段は、泡吸い込み口９と泡吸引の駆動源となるエジェクター１０とからなり、泡吸い込み口９は循環タンク５の第１区画７の上部に設けられる。エジェクター１０は消泡箱１１に接続され、これに泡吸い込み口９に接続された配管と、駆動流体用の配管が接続される。エジェクタ−１０は、泡を消泡箱１１の衝突板１２に高速度で送り込むものであり、エジェクター１０としては、蒸気エジェクターおよび空気エジェクター等を使用することができる。
【００２４】
前記消泡箱１１は、内部に網状の衝突板１２と仕切壁１３を有している。衝突板１２は網状の邪魔板からなり、エジェクター１０から排出された泡は衝突板１２に向けて噴射され衝突するようになっている。消泡箱内の雰囲気は大気放散している。
【００２５】
前記不純物分離タンク１５は、消泡箱１１から管１４を通って流入する不純物を含んだ消泡液を矢印のように流し、その流れ方向において複数段階に亘って液中不純物成分の沈降・分離を行わせるため、タンク上部から垂設して下部が液に没入する仕切り板１６とタンク底に立設された堰１７を液の流れ方向に沿って、交互にそれぞれ複数設けている。ここに、仕切り板１６は消泡液を下から通し、堰１７は消泡液を上から溢流させる。また、不純物分離タンク１５は液の分離区画滞留時間が少なくとも１５分以上となるような実効容積を有している。さらに、前記各分離区画毎において分離された油分および石鹸分等１８、鉄分等１９を、各分離区画毎に抜出し管２１によりタンク外に排出している。不純物分離タンク１５の出側区画Ｃにはレベル計２０を設けている。
【００２６】
前記配管系２２、２４は、不純物分離タンク１５の液出側から排出された液を回収液循環ポンプ２３により前記循環タンク５に供給するものである。
【００２７】
次に、洗浄設備で発生する洗浄液の泡の処理工程について説明する。洗浄タンク２で鋼帯１を洗浄液に浸漬させる方法等で脱脂洗浄すると、洗浄液３の上層部には泡３０を混入した洗浄液の液層ができる。この泡を混入した洗浄液は、管４を通って循環タンク５の第１区画７に流入する。前記洗浄液が流入すると循環タンク５に貯留されている洗浄液３との混合により大量の泡３０が発生し、この泡で第１区画が満たされるが、仕切壁６があるので泡は第２区画８には流入しない。ここで、循環タンク５の仕切壁６は無くても良いが、泡吸い込み口９に対して泡を効率的に誘導するためには仕切壁６が有る方が望ましい。
【００２８】
この泡３０には洗浄液とともに、油分および石鹸分等１８、鉄分等１９が付着している。第１区画７の泡３０は、第１区画７内に設けられた泡吸い込み口９を介してエジェクタ−１０により吸引され、高速で消泡箱１１の衝突板１２に向けて噴射される。ここで、泡吸い込み口９は、循環タンクの液面レベルに対して上下方向に追従することが望ましい。泡吸い込み口９が循環タンクの液面レベルの直上となるよう上下方向に追従すれば、洗浄液３を吸引することなく、循環タンク第１区画７の泡のみを最も効率良く吸引できる。例えば、泡吸い込み口９を循環タンクの液面レベルに対して上下方向に追従させる手段としては、液面にフロート体を設けて、このフロート体と泡吸い込み口９とを接続する部材を介して、泡吸い込み口９を上下に移動させればよい。
【００２９】
ここで、エジェクター１０として蒸気エジェクターを用いることが望ましい。これは、エジェクタ−１０を用いた場合の、泡に運動エネルギ−を与えることによる泡のせん断破泡、および衝突板への泡の衝突破泡に対して、蒸気熱による泡の膨張破泡が加わり、効率良い泡の破泡（または、消泡）が行われ、泡はほぼ１００％破泡されるためである。
【００３０】
また、後述する実施例の記載のように、エジェクタ−に蒸気エジェクターを用いてこの蒸気エジェクタ−に使用する蒸気の圧力と破泡状況を試験した結果、蒸気圧力が３〜４ｋｇ／ｃｍ²のとき、良好な泡の吸引および破泡が得られることがわかった。
【００３１】
泡は、衝突板１２に衝突して破泡して液となり消泡箱１１の底部の液溜まりに貯まる。前記消泡箱１１の底部に貯まった消泡液は、油分、石鹸分および鉄分等の不純物を混入した洗浄液である。この不純物を含む洗浄液３ａは、管１４を通って不純物分離タンク１５の入側区画Ａの下部に流入する。
【００３２】
不純物分離タンク１５に流入した不純物を含む洗浄液は、矢印のように仕切り板１６下で反転し、堰１７を溢流して入側区画Ａ→中間区画Ｂ→出側区画Ｃの順に流れる。各区画において、洗浄液より比重の小さい油分および石鹸分等１８が洗浄液３ｂの上に浮上し、洗浄液より比重の重い鉄分等１９がタンク底に沈降する沈降・分離が行われる。各区画において不純物の浮上・沈降分離が行われるので、入側区画Ａ→中間区画Ｂ→出側区画Ｃの順に洗浄液に含まれる不純物の量が減少し、出側区画Ｃで不純物のほとんど無い洗浄液３ｃが分離、回収される。
【００３３】
なお、複数の仕切り板１６およびタンク底に立設した堰１７は無くても良いが、複数の仕切り板１６およびタンク底に立設した堰１７により区画に区分すれば、前記の沈降・分離により出側区画Ｃの清浄化を図れるため、有る方が望ましい。
【００３４】
なお、各区画では、例えば所定の回収量または回収時間に達する毎に、油分および石鹸分等１８、鉄分等１９の不純物が各区画の洗浄液とともに抜出し管２１によりタンク外に排出されることが望ましい。
【００３５】
出側区画Ｃの不純物が除去された回収洗浄液３ｃは、レベル計２０により液レベルが一定に制御され、吸込み管２２、回収液循環ポンプ２３および排出管２４を経由して循環タンク５の第２区画８に流入する。ここで、出側区画Ｃに濃度計を設置し、回収洗浄液３ｃの濃度に異常（極度の濃度低下等）が認められる場合は、回収洗浄液３ｃの循環タンク５への流入の際に濃度変動が生じる可能性が有るため、出側区画Ｃの回収洗浄液３ｃを抜き出し管２１によりタンク外に排出しても良い。また、出側区画Ｃに温度計を設置し、回収液３ｃの温度に異常（極度の温度上昇・低下）が認められる場合は、回収洗浄液３ｃの循環タンク５への流入の際に温度変動が生じる可能性が有るため、出側区画Ｃの回収洗浄液３ｃを抜き出し管２１によりタンク外に排出しても良い。
【００３６】
循環タンク５に貯留されている洗浄液３は、吸込み管、循環ポンプ２６および排出管２７を経由して洗浄タンク２に再び戻され、鋼帯１の脱脂洗浄に供せられる。なお、洗浄タンク２における洗浄工程および回収洗浄液の循環過程において、鋼帯に付着して持ち去られたり、蒸発等により洗浄液の一部が失われるので、この損失分を補給するために洗浄液の補給タンク２８が設けられている。洗浄液は、補給タンク２８から管２９を経由して循環タンク５に対して行われる。なお、洗浄液の補給タンク２８の代わりに、洗浄液の原液と希釈用の水のタンクを個別に設置し、それぞれ必要に応じて個別に補給される形であっても良い。
【００３７】
（１）破泡により生じた洗浄液を直接、循環タンクに戻し、循環タンクから洗浄タンクに戻す方法：従来装置による方法（特開平１１−３６０９０号装置による方法）と（２）破泡により生じた洗浄液を不純物分離タンクで不純物を除去した後で循環タンクを経由して洗浄タンクに戻す方法：本発明装置による方法について、それぞれ、１カ月間運転して循環タンクに投入する回収洗浄液の清浄度（アルカリ濃度、油分、石鹸分および鉄分の変化）を比較調査した。この結果を表１に示す。
【００３８】
【表１】

【００３９】
表１は、従来装置による方法では、回収液中の油分、石鹸分および鉄分が大幅に増加し、汚れが目立つのに対し、本発明装置による方法では、油分が若干増加している以外は新しい洗浄液と変わらない清浄度を示している。
【００４０】
本発明装置により、循環タンクに補給する新洗浄液の量を減らすことが可能となり、洗浄剤の購入費用を節減することが可能になった。また、循環タンクから泡の溢れ出しを防止することが可能となり、作業環境の改善が図られた。
【００４１】
図２は、本発明の洗浄設備の他の実施形態を示す概略図である。
【００４２】
図２は、表面に油脂等が付着した金属材を洗浄するための洗浄タンクと、洗浄タンクとの間で洗浄液を循環させるための循環タンクと、洗浄タンク内の洗浄液の泡を吸引するための泡吸引手段と、泡吸引手段により吸引された泡が供給され、破泡がなされる消泡箱と、該消泡箱での破泡により生じた液が供給され、該液中の不純物成分の分離除去を行う不純物分離タンクと、不純物分離タンクで不純物成分が分離除去された液を前記循環タンクに供給する配管系とを備えている。
【００４３】
この図２の実施形態では、洗浄タンク２で鋼帯１を脱脂洗浄して、洗浄液３の上層部には泡３０を混入した洗浄液の液層ができるが、この泡３０を循環タンク５を介さずに、直接洗浄タンク２から吸引する方式としたもので、このため泡吸引手段の泡吸い込み口９は洗浄タンク２に設けられる。他の構成は図１の実施形態と全く同様である
エジェクター１０としては、蒸気エジェクターおよび空気エジェクター等を使用することができ、蒸気エジェクターを用いるときは、蒸気エジェクターの圧力設定値を３〜４ｋｇ／ｃｍ²とすることが好ましい。
【００４４】
図２においても、不純物分離タンク１５が、複数の仕切り板１６と複数の堰１７により分けられた複数段の分離区画を有すること、洗浄タンク２に設置された泡吸い込み口９は洗浄タンク内の洗浄液の液面レベルに追従して上下方向に昇降すること、不純物分離タンク１５は消泡液の分離区画滞留時間が少なくとも１５分以上となるような実効容積を有すること、および不純物分離タンク１５は前記各分離区画毎において分離された不純物を、各分離区画毎にタンク外に排出するための排出手段を有することは、図１の実施形態と同様である。
【００４５】
【実施例】
図１の装置を用いて本発明法を連続焼鈍装置の洗浄設備に適用して実施した。ここで、エジェクターとして蒸気エジェクターを用いた。洗浄設備では洗浄液の主成分として苛性ソーダを用い、洗浄液の各種条件設定は以下とした。循環タンク内のアルカリ濃度（洗浄有効分濃度）：１．８（％）、循環タンク内のアルカリ温度：７０（℃）、循環タンク全容積：３０（ｍ³）、循環タンク中のアルカリ液容積：１５（ｍ³）。
【００４６】
定期修理後、全て新液状態から操業を開始した。消泡液循環装置を使用しない状態で２〜３日後には循環タンク上に常時泡が発生し、循環タンク外に流出した。
【００４７】
次に、消泡液循環装置の運転条件として蒸気エジェクター圧力設定を２．５ｋｇ／ｃｍ²、３ｋｇ／ｃｍ²、４ｋｇ／ｃｍ²の３水準に設定して洗浄設備を運転し、泡を回収し、回収洗浄液の回収量、回収洗浄液の性状、蒸気使用量等を調査した。
【００４８】
表２は洗浄設備運転結果を示す。
【００４９】
【表２】

【００５０】
表２で２．５ｋｇ／ｃｍ²では回収洗浄液量が少なく温度も低くなった。また泡の回収率も１００％でなく、循環タンク外へ泡が溢れ出した。４ｋｇ／ｃｍ²では循環タンクから泡は溢れ出さないが、回収洗浄液のアルカリ濃度が低下傾向にありさらに温度が高すぎる。本実施例における、不純物分離タンクから循環タンクへの回収洗浄液の送液ポンプは耐熱温度が９０℃である。また、回収量が多過ぎるため、不純物分離タンク第１層での液面変動が激しい。
【００５１】
その結果表２より、主たる成分が苛性ソーダである洗浄液を用いた場合は、蒸気エジェクターの圧力設定は３ｋｇ／ｃｍ²〜４ｋｇ／ｃｍ² が好ましい。しかるに回収洗浄液量からは、蒸気エジェクター圧力設定が４ｋｇ／ｃｍ²が最も好ましい条件であるが、回収洗浄液温度、回収洗浄液濃度と併せて鑑みると蒸気エジェクター圧力設定が３ｋｇ／ｃｍ²が最適条件となる。
【００５２】
次に図１の消泡箱１１から出る不純物を含む洗浄液３ａを、管１４からサンプリングし、メスシリンダーにサンプル液を静置し、液分離状況を時系列的に目視で観察した。その結果、サンプル液が上層部に油分・石鹸分、中間層に洗浄液、下層部に鉄分という成分に分離するのに約１５分以上の静置時間が必要であることとがわかった。この実験結果から、消泡液の分離区画滞留時間が少なくとも１５分以上となるような不純物分離タンクの実効容積を有することが望ましい。
【００５３】
【発明の効果】
本発明装置によれば、泡を消泡して得られる不純物を含んだ消泡液を不純物分離タンクに通すことにより不純物を除去し、得られた液を回収洗浄液として循環タンクに戻すから、回収洗浄液の洗浄能力を長期間維持することができる。このことにより、洗浄液の補給量が低下するから、洗浄剤の購入費用を節減できる。また、蒸気エジェクタ−と消泡箱の組合せにより、効率良い消泡（破泡）が実現できる。また、効率良い消泡の実現により循環タンク周囲の作業環境を改善することできる。
【図面の簡単な説明】
【図１】本発明の金属材の洗浄設備の一実施形態を示す概略図である。
【図２】本発明の金属材の洗浄設備の他の実施形態を示す概略図である。
【符号の説明】
１鋼帯
２洗浄タンク
３洗浄液
３ａ不純物を含む洗浄液（または、消泡液）
３ｂ不純物分離タンク入側区画の洗浄液
３ｃ回収洗浄液
５循環タンク
６仕切壁
７循環タンクの第１区画
８循環タンクの第２区画
９泡吸い込み口
１０エジェクタ−
１１消泡箱
１２衝突板
１３仕切壁
１５不純物分離タンク
１６仕切り板
１７堰（溢流）
２３回収液循環ポンプ
２６循環ポンプ
２８補給タンク
３０泡[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a facility for cleaning a metal material such as a steel strip, and relates to a facility capable of defoaming bubbles generated during cleaning and reusing the liquid generated by the defoaming as a cleaning liquid. .
[0002]
[Prior art]
Generally, in cleaning equipment for steel strips, etc., using an alkaline aqueous solution such as caustic soda or orthosilicate soda as a cleaning liquid, a method of immersing the steel strip in the cleaning liquid, a method of spraying the cleaning liquid on the steel strip, etc. In addition, it is possible to perform electrolysis in a state where the steel strip is immersed in the cleaning solution or in a state where the cleaning solution is sprayed on the steel strip, and further, brushing in a state where the steel strip is immersed in the cleaning solution or the cleaning solution is sprayed For example, rolling oil adhering to the surface of a steel strip or the like is degreased and washed by a combination of methods. In this degreasing cleaning, cleaning fluid such as rolling oil and alkaline aqueous solution causes a chemical reaction, a large amount of bubbles are generated in the cleaning tank or circulation tank of the cleaning equipment, and bubbles overflow from the tank and the cleaning liquid is lost. Invite. For this reason, it is necessary to replenish the cleaning liquid, and the cost increases due to the purchase cost of the cleaning liquid. In addition, since the cleaning liquid is often used after raising the temperature from room temperature in order to ensure cleaning properties, a large amount of heat energy such as steam is consumed as the cleaning liquid is replenished. In addition, since the bubbles overflow outside the tank, the working environment around the tank is remarkably deteriorated, and processing costs as waste liquid are required. In order to prevent the foam from overflowing, it is generally performed to add an antifoaming agent into the cleaning liquid. However, a large amount of an expensive antifoaming agent must be continuously added. Cost increases due to purchase costs. Further, even if an antifoaming agent is added, the defoaming does not become 100%, and it is not a decisive factor for defoaming measures.
[0003]
An apparatus for solving such a problem is disclosed in the following publication. In Japanese Patent Laid-Open No. 3-153877, a foamed alkaline cleaning liquid is stored in a storage tank, and bubbles generated in the upper part of the storage tank are guided to an overflow tank, and bubbles in the overflow tank are introduced. On the other hand, the apparatus which sprays mist-like water and defoams is disclosed. Japanese Patent Application Laid-Open No. 6-49544 discloses a device that blows off hot bubbles of 50 ° C. to 300 ° C. against bubbles generated in a steel strip degreasing and cleaning tank and a cleaning liquid circulation tank. .
[0004]
On the other hand, an apparatus for reusing an antifoaming liquid as a cleaning liquid is disclosed in Japanese Patent Laid-Open No. 11-36090. This is a method in which foam generated in the washing tank is sent to a defoaming box by an ejector, the liquid generated by defoaming is stored in a circulation tank, and the stored liquid is returned to the washing tank as a washing liquid by a circulation pump. is there.
[0005]
[Problems to be solved by the invention]
However, as in the apparatus disclosed in Japanese Patent Laid-Open No. 3-153877, the one that sprays mist water on the foam requires a large amount of sprayed water, so there is a problem that the concentration of the cleaning liquid after defoaming becomes thin. . In addition, since the mist water collides with the cleaning liquid surface that has been removed by spraying the mist water and foams, complete defoaming cannot be performed. For this reason, when there are many generation | occurrence | production of a bubble, it was inadequate to prevent the overflow of the bubble from an overflow tank. In addition, a device that blows hot air against a foam, such as a device disclosed in JP-A-6-49544, requires a large amount of hot air to maintain a defoaming ability commensurate with foaming. There was a problem that complete defoaming was impossible in a short time.
[0006]
On the other hand, in the apparatus of JP-A-11-36090, it is possible to discharge the generated bubbles in a larger amount than before, and the discharged bubbles can be almost 100% defoamed. However, oil, iron powder, etc. are mixed. Since the liquid after defoaming is returned to the circulation tank as it is, there is a problem that the cleaning ability of the cleaning liquid decreases with time.
[0007]
The present invention provides a metal material cleaning facility capable of efficiently defoaming generated foam, reusing the defoaming liquid generated by the defoaming as a cleaning liquid, and appropriately preventing a decrease in cleaning performance after cleaning. For the purpose.
[0008]
[Means for Solving the Problems]
The metal material cleaning facility of the present invention has the following characteristics.
[0009]
(1) a cleaning tank for cleaning metal materials with oils and fats on the surface;
A circulation tank for circulating the cleaning liquid to and from the cleaning tank;
Foam suction means for sucking bubbles of the cleaning liquid in the circulation tank;
A defoaming box in which bubbles sucked by the bubble sucking means are supplied and bubbles are broken;
An impurity separation tank that is supplied with a liquid generated by bubble breaking in the defoaming box and separates and removes impurity components in the liquid;
A metal material cleaning facility comprising: a piping system for supplying a liquid from which impurity components have been separated and removed in the impurity separation tank to the circulation tank.
[0010]
(2) The circulation tank has a partition wall into which the lower part is immersed in the cleaning liquid stored in the tank, and the cleaning liquid from the cleaning tank is received in one of the sections divided by the partition wall. The metal material cleaning facility according to (1) above, which is characterized by the following.
[0011]
(3) The impurity separation tank has a plurality of separation sections divided by a plurality of partition plates and a plurality of weirs suspended from the upper part of the tank, as described in (1) or (2) above Cleaning equipment for metal materials.
[0012]
(4) The metal according to any one of (1) to (3) above, wherein the foam suction port of the foam suction means moves up and down following the liquid level of the cleaning liquid in the circulation tank. Material cleaning equipment.
[0013]
(5) The impurity separation tank having the separation section has an effective volume such that the retention time of the separation section of the liquid is at least 15 minutes or more. Cleaning equipment for metal materials.
[0014]
(6) The above-described (3) to (3), wherein the impurity separation tank having a separation section has discharge means for discharging impurities separated in each separation section to the outside of the tank for each separation section. (5) The metal material cleaning facility according to any one of (5).
[0015]
(7) The metal material cleaning equipment according to any one of (1) to (6) above, wherein a steam ejector is used as the bubble suction means.
[0016]
(8) A cleaning tank for cleaning a metal material having oils or the like attached to its surface, a circulation tank for circulating the cleaning liquid between the cleaning tank, and a bubble of the cleaning liquid in the cleaning tank The foam suction means, the foam sucked by the foam suction means is supplied, the defoaming box is broken, and the liquid generated by the foam breaking in the defoaming box is supplied, and the impurities in the liquid An impurity separation tank having a plurality of separation sections divided by a plurality of partition plates suspended from the upper part of the tank and a plurality of weirs , and the impurity components are separated and removed by the impurity separation tank. A metal material cleaning facility comprising: a piping system for supplying liquid to the circulation tank.
[0017]
In the present invention, a liquid containing impurities obtained by defoaming the foam after washing (hereinafter referred to as “defoaming liquid”) is passed through an impurity separation tank to remove impurities, and the resulting liquid is recovered. Since the cleaning liquid is returned to the circulation tank, the cleaning ability of the cleaning liquid can be maintained for a long time. As a result, the replenishment amount of the cleaning liquid can be reduced, so that the purchase cost of the cleaning liquid can be reduced. Further, since the replenishment amount of the cleaning liquid can be reduced, thermal energy such as steam necessary for temperature rise can be saved. Furthermore, in order to prevent the bubbles from overflowing outside the tank, the working environment around the tank is improved, and the processing cost as waste liquid becomes unnecessary.
[0018]
In the following description, the soap component refers to fatty acid sodium produced when the rolling oil adhering to the steel strip surface undergoes hydrolysis (saponification) reaction with alkali in the cleaning solution, and the oil component refers to the rolling oil. The sum of the unsaponified oil component that does not cause the saponification reaction therein and the unsaponified oil component present because the saponification reaction in the rolling oil is insufficient, and the iron component refers to the wear powder mainly generated from the surface of the steel strip.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic view showing an embodiment of the cleaning equipment of the present invention.
[0020]
FIG. 1 shows a cleaning tank 2 for cleaning a metal material with oils and fats on its surface, a circulation tank 5 for circulating the cleaning liquid 3 between the cleaning tank 2 and bubbles of the cleaning liquid 3 in the circulation tank. A foam suction means for sucking the foam, the foam sucked by the foam suction means is supplied, the defoaming box 11 is broken, and the liquid generated by the foam breaking in the defoaming box 11 is supplied, An impurity separation tank 15 that separates and removes impurity components therein, and

piping systems

22 and 24 that supply the liquid from which the impurity components are separated and removed in the impurity separation tank 15 to the circulation tank 5 are provided.
[0021]
The cleaning tank 2 is filled with a cleaning liquid for cleaning a steel strip or the like having oil or fat attached to its surface, and the steel strip 1 is continuously passed.
[0022]
In the circulation tank 5, the upper space of the cleaning liquid is divided into a first section 7 and a second section 8 by a partition wall 6 in which a lower portion is immersed in the cleaning liquid 3 stored in the tank. Then, the liquid from the cleaning tank 2 is supplied to the first section 7 through the pipe 4.
[0023]
The foam suction means includes a foam suction port 9 and an ejector 10 that is a drive source for foam suction. The foam suction port 9 is provided in the upper part of the first section 7 of the circulation tank 5. The ejector 10 is connected to a defoaming box 11, and a pipe connected to the foam suction port 9 and a pipe for driving fluid are connected thereto. The ejector 10 feeds the foam to the collision plate 12 of the defoaming box 11 at a high speed. As the ejector 10, a steam ejector, an air ejector, or the like can be used.
[0024]
The defoaming box 11 has a net-like collision plate 12 and a partition wall 13 inside. The collision plate 12 is made of a net-like baffle plate, and bubbles discharged from the ejector 10 are jetted toward the collision plate 12 and collide with each other. The atmosphere inside the defoaming box is dissipated into the atmosphere.
[0025]
The impurity separation tank 15 allows the defoaming liquid containing impurities flowing from the defoaming box 11 through the pipe 14 to flow as indicated by arrows, and the sedimentation / separation of the impurity components in the liquid is performed in a plurality of stages in the flow direction. In order to perform this, a plurality of partition plates 16 suspended from the upper part of the tank and immersed in the liquid at the lower part and weirs 17 erected on the tank bottom are alternately provided along the liquid flow direction. Here, the partition plate 16 allows the antifoaming liquid to pass from below, and the weir 17 causes the antifoaming liquid to overflow from above. Further, the impurity separation tank 15 has an effective volume such that the liquid separation section residence time is at least 15 minutes. Further, the oil and soap components 18 and the iron component 19 and the like 19 separated in each separation section are discharged out of the tank through the extraction pipe 21 for each separation section. A level meter 20 is provided in the outlet section C of the impurity separation tank 15.
[0026]
The

piping systems

22 and 24 supply the liquid discharged from the liquid discharge side of the impurity separation tank 15 to the circulation tank 5 by a recovery liquid circulation pump 23.
[0027]
Next, a process for treating the foam of the cleaning liquid generated in the cleaning facility will be described. When the cleaning tank 2 is degreased and cleaned by a method of immersing the steel strip 1 in the cleaning liquid, a liquid layer of the cleaning liquid in which bubbles 30 are mixed is formed on the upper layer of the cleaning liquid 3. The cleaning liquid mixed with the bubbles flows into the first section 7 of the circulation tank 5 through the pipe 4. When the cleaning liquid flows in, a large amount of foam 30 is generated by mixing with the cleaning liquid 3 stored in the circulation tank 5, and the foam fills the first section. However, since the partition wall 6 exists, the foam is in the second section 8 Does not flow into. Here, the partition wall 6 of the circulation tank 5 may be omitted, but it is desirable that the partition wall 6 is provided in order to efficiently guide the bubbles to the bubble suction port 9.
[0028]
Along with the cleaning liquid, the foam 30 has an oil and soap part 18 and an iron part 19 attached thereto. The foam 30 in the first section 7 is sucked by the ejector 10 through the foam suction port 9 provided in the first section 7 and is jetted toward the collision plate 12 of the defoaming box 11 at a high speed. Here, it is desirable that the bubble suction port 9 follows the liquid level of the circulation tank in the vertical direction. If the bubble suction port 9 follows in the vertical direction so as to be directly above the liquid level of the circulation tank, only the bubbles in the circulation tank first section 7 can be most efficiently sucked without sucking the cleaning liquid 3. For example, as means for causing the foam suction port 9 to follow the liquid level of the circulation tank in the vertical direction, a float body is provided on the liquid surface, and a member that connects the float body and the foam suction port 9 is used. The bubble suction port 9 may be moved up and down.
[0029]
Here, it is desirable to use a steam ejector as the ejector 10. This is because, when the ejector 10 is used, the bubble expansion due to steam heat is caused by the bubble shear breakage caused by imparting kinetic energy to the bubble and the bubble breakage of the bubble against the collision plate. In addition, efficient bubble breaking (or defoaming) is performed, and the bubbles are broken almost 100%.
[0030]
In addition, as described in the examples to be described later, when the steam pressure is 3 to 4 kg / cm ² as a result of testing the steam pressure and the state of bubble breakage using the steam ejector as the ejector. It was found that good bubble suction and bubble breakage were obtained.
[0031]
The foam collides with the collision plate 12 and breaks to become liquid, and is stored in the liquid reservoir at the bottom of the defoaming box 11. The defoaming liquid stored at the bottom of the defoaming box 11 is a cleaning liquid in which impurities such as oil, soap and iron are mixed. The cleaning liquid 3 a containing impurities flows through the pipe 14 into the lower part of the entry side section A of the impurity separation tank 15.
[0032]
The cleaning liquid containing impurities flowing into the impurity separation tank 15 is reversed under the partition plate 16 as shown by the arrow, overflows the weir 17 and flows in the order of entry side section A → intermediate section B → outside section C. In each section, an oil component and a soap component 18 having a specific gravity smaller than that of the cleaning liquid float on the cleaning liquid 3b, and an iron component 19 having a higher specific gravity than the cleaning liquid settles on the bottom of the tank. Since the floating and sedimentation of impurities is performed in each section, the amount of impurities contained in the cleaning solution decreases in the order of entry side section A → intermediate section B → outside section C, and the cleaning solution containing almost no impurities in the exit side section C. 3c is separated and recovered.
[0033]
The plurality of partition plates 16 and the weirs 17 standing on the tank bottom may be omitted. However, if the partition plates 16 and the weirs 17 standing on the tank bottom are divided into compartments, Since the exit side section C can be cleaned, it is desirable to have it.
[0034]
In each section, for example, every time a predetermined recovery amount or recovery time is reached, it is desirable that impurities such as oil and soap 18 and iron 19 are discharged from the tank together with the cleaning liquid of each section through the extraction pipe 21. .
[0035]
The level of the recovered cleaning liquid 3c from which impurities in the outlet section C have been removed is controlled to be constant by the level meter 20, and the second level of the circulation tank 5 passes through the suction pipe 22, the recovered liquid circulation pump 23, and the discharge pipe 24. It flows into the compartment 8. Here, if a densitometer is installed in the outlet section C, and the concentration of the recovered cleaning liquid 3c is abnormal (extreme decrease in concentration, etc.), the concentration fluctuation occurs when the recovered cleaning liquid 3c flows into the circulation tank 5. Since there is a possibility that it will occur, the recovered cleaning liquid 3c in the outlet section C may be discharged out of the tank through the extraction pipe 21. In addition, when a thermometer is installed in the outlet side section C and the temperature of the recovered liquid 3c is abnormal (extreme temperature rise / decrease), temperature fluctuation occurs when the recovered cleaning liquid 3c flows into the circulation tank 5. Since there is a possibility that it will occur, the recovered cleaning liquid 3c in the outlet section C may be discharged out of the tank through the extraction pipe 21.
[0036]
The cleaning liquid 3 stored in the circulation tank 5 is returned again to the cleaning tank 2 via the suction pipe, the circulation pump 26 and the discharge pipe 27 and is used for degreasing and cleaning the steel strip 1. In the cleaning process in the cleaning tank 2 and the circulation process of the recovered cleaning liquid, the cleaning liquid is removed by adhering to the steel strip or lost due to evaporation or the like. 28 is provided. The cleaning liquid is supplied from the replenishing tank 28 to the circulation tank 5 via the pipe 29. Instead of the cleaning liquid replenishing tank 28, a tank of the cleaning liquid and a tank of water for dilution may be provided separately and replenished individually as necessary.
[0037]
(1) A method of returning the cleaning liquid generated by bubble breaking directly to the circulation tank and returning from the circulation tank to the washing tank: a method using a conventional device (a method using Japanese Patent Laid-Open No. 11-36090) and (2) a method caused by bubble breaking Method of returning the cleaning liquid to the cleaning tank via the circulation tank after removing impurities in the impurity separation tank: For the method according to the present invention, the cleanliness of the recovered cleaning liquid that is operated for one month and put into the circulation tank ( Comparison of alkali concentration, oil content, soap content and iron content). The results are shown in Table 1.
[0038]
[Table 1]

[0039]
Table 1 shows that the oil, soap, and iron contents in the recovered liquid are greatly increased and dirt is conspicuous in the method using the conventional apparatus, whereas the method using the apparatus of the present invention is new except that the oil content is slightly increased. The cleanliness is the same as the cleaning liquid.
[0040]
The apparatus of the present invention makes it possible to reduce the amount of new cleaning liquid to be replenished to the circulation tank, thereby reducing the purchase cost of the cleaning agent. In addition, it was possible to prevent bubbles from overflowing from the circulation tank, and the working environment was improved.
[0041]
FIG. 2 is a schematic view showing another embodiment of the cleaning equipment of the present invention.
[0042]
FIG. 2 shows a cleaning tank for cleaning a metal material with oils and fats attached to the surface, a circulation tank for circulating the cleaning liquid between the cleaning tank, and a bubble for cleaning liquid in the cleaning tank. A foam suction means, a foam sucked by the foam suction means, a defoaming box in which bubbles are broken, and a liquid generated by the foam breaking in the defoaming box are supplied, and the impurity components in the liquid are An impurity separation tank that performs separation and removal, and a piping system that supplies the liquid from which the impurity components have been separated and removed in the impurity separation tank to the circulation tank are provided.
[0043]
In the embodiment of FIG. 2, the steel strip 1 is degreased and cleaned in the cleaning tank 2, and a liquid layer of cleaning liquid in which bubbles 30 are mixed is formed in the upper layer of the cleaning liquid 3. Instead, the suction tank 9 is directly sucked from the washing tank 2, and the foam suction port 9 of the foam suction means is provided in the washing tank 2 for this purpose. Other configurations are exactly the same as those of the embodiment of FIG. 1. As the ejector 10, a steam ejector, an air ejector, or the like can be used. Preferably it is cm ² .
[0044]
Also in FIG. 2, the impurity separation tank 15 has a plurality of separation sections divided by a plurality of partition plates 16 and a plurality of weirs 17, and the foam suction port 9 installed in the cleaning tank 2 is located in the cleaning tank. Following up and down in the vertical direction following the liquid level of the cleaning liquid, the impurity separation tank 15 has an effective volume such that the defoaming liquid residence time in the separation section is at least 15 minutes, and the impurity separation tank 15 It is the same as in the embodiment of FIG. 1 that there is a discharge means for discharging the impurities separated in each separation section to the outside of the tank in each separation section.
[0045]
【Example】
The method of the present invention was applied to the cleaning equipment of a continuous annealing apparatus using the apparatus of FIG. Here, a steam ejector was used as the ejector. In the cleaning equipment, caustic soda was used as the main component of the cleaning liquid, and various conditions of the cleaning liquid were set as follows. Concentration of alkali in the circulation tank (concentration of cleaning effective component): 1.8 (%), alkali temperature in the circulation tank: 70 (° C.), total volume of the circulation tank: 30 (m ³ ), volume of alkali liquid in the circulation tank : 15 (m ³ ).
[0046]
After regular repairs, all operations started from the new solution. After 2 to 3 days without using the antifoaming liquid circulation device, bubbles were constantly generated on the circulation tank and flowed out of the circulation tank.
[0047]
Next, the steam ejector pressure setting ^{2.5kg / cm 2, 3kg / cm} 2, is set to 3 levels of 4 kg / cm ² the washing installation and operation, the foam was recovered as the operating conditions of the defoaming liquid circulating device The amount of recovered cleaning liquid collected, the properties of the recovered cleaning liquid, the amount of steam used, etc. were investigated.
[0048]
Table 2 shows the results of operating the cleaning equipment.
[0049]
[Table 2]

[0050]
In Table 2, at 2.5 kg / cm ² , the amount of recovered cleaning liquid was small and the temperature was low. Also, the foam recovery rate was not 100%, and the foam overflowed out of the circulation tank. At 4 kg / cm ² , bubbles do not overflow from the circulation tank, but the alkali concentration of the recovered cleaning liquid tends to decrease and the temperature is too high. In this embodiment, the heat pump temperature of the liquid feed pump for the recovered cleaning liquid from the impurity separation tank to the circulation tank is 90 ° C. Further, since the recovered amount is too large, the liquid level fluctuation in the first layer of the impurity separation tank is severe.
[0051]
From a result table 2, if the main component is used a cleaning solution is sodium hydroxide, the pressure setting of the steam ejector is preferably ^{^{3kg / cm 2 ~4kg / cm 2}} . However, from the viewpoint of the amount of the recovered cleaning liquid, the steam ejector pressure setting of 4 kg / cm ² is the most preferable condition. However, considering the recovered cleaning liquid temperature and the recovered cleaning liquid concentration, the optimal condition is the steam ejector pressure setting of 3 kg / cm ^2. .
[0052]
Next, the cleaning liquid 3a containing impurities coming out of the defoaming box 11 of FIG. 1 was sampled from the tube 14, the sample liquid was allowed to stand in a graduated cylinder, and the liquid separation situation was visually observed in time series. As a result, it was found that a standing time of about 15 minutes or more was required for the sample liquid to be separated into components of oil / soap in the upper layer, cleaning liquid in the intermediate layer, and iron in the lower layer. From this experimental result, it is desirable to have an effective volume of the impurity separation tank so that the defoaming liquid residence time in the separation compartment is at least 15 minutes or more.
[0053]
【The invention's effect】
According to the device of the present invention, the defoaming liquid containing impurities obtained by defoaming the foam is removed by passing the impurities through the impurity separation tank, and the obtained liquid is returned to the circulation tank as a recovery washing liquid. The cleaning ability of the cleaning liquid can be maintained for a long time. As a result, the replenishment amount of the cleaning liquid is reduced, so that the purchase cost of the cleaning agent can be reduced. Moreover, efficient defoaming (bubble breakage) can be realized by a combination of a steam ejector and a defoaming box. In addition, the work environment around the circulation tank can be improved by realizing efficient defoaming.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an embodiment of a metal material cleaning facility of the present invention.
FIG. 2 is a schematic view showing another embodiment of the metal material cleaning equipment of the present invention.
[Explanation of symbols]
1 Steel strip 2 Cleaning tank 3 Cleaning liquid 3a Cleaning liquid containing impurities (or antifoaming liquid)
3b Cleaning liquid 3c in impurity separation tank inlet side section Recovery cleaning liquid 5 Circulating tank 6 Partition wall 7 First section of circulating tank 8 Second section of circulating tank 9 Foam inlet 10 Ejector
11 Antifoaming box 12 Collision plate 13 Partition wall 15 Impurity separation tank 16 Partition plate 17 Weir (overflow)
23 Recovery liquid circulation pump 26 Circulation pump 28 Replenishment tank 30 Foam

Claims

A cleaning tank for cleaning metal materials having oils and fats attached to the surface, a circulation tank for circulating the cleaning liquid between the cleaning tank, and a bubble suction for sucking bubbles of the cleaning liquid in the circulation tank And a defoaming box in which bubbles sucked by the bubble sucking means are supplied and bubbles are broken, and a liquid generated by the defoaming in the defoaming box is supplied, and separation of impurity components in the liquid is performed. An apparatus for cleaning a metal material, comprising: an impurity separation tank that performs removal; and a piping system that supplies a liquid from which impurity components are separated and removed in the impurity separation tank to the circulation tank.

The circulation tank has a partition wall in which a lower part is immersed in the cleaning liquid stored in the tank, and the cleaning liquid from the cleaning tank is received in one of the sections divided by the partition wall. The metal material cleaning facility according to claim 1.

The metal material cleaning facility according to claim 1 or 2, wherein the impurity separation tank has a plurality of separation sections divided by a plurality of partition plates and a plurality of weirs suspended from the upper part of the tank.

The metal material cleaning equipment according to any one of claims 1 to 3, wherein the foam suction port of the foam suction means moves up and down in accordance with the level of the cleaning liquid in the circulation tank.

The metal material cleaning equipment according to claim 3 or 4, wherein the impurity separation tank having the separation section has an effective volume such that the liquid separation section residence time is at least 15 minutes or more.

6. The impurity separation tank having a separation section has discharge means for discharging impurities separated in each separation section to the outside of the tank for each separation section. Equipment for cleaning metal materials as described in 1.

The metal material cleaning equipment according to any one of claims 1 to 6, wherein a steam ejector is used as the foam suction means.

A cleaning tank for cleaning metal materials with oils and fats attached to the surface, a circulation tank for circulating cleaning liquid between the cleaning tank, and foam suction for sucking bubbles of the cleaning liquid in the cleaning tank And a defoaming box in which bubbles sucked by the foam sucking means are supplied and bubbles are broken, and a liquid generated by the defoaming in the defoaming box is supplied to separate the impurity components in the liquid An impurity separation tank having a plurality of separation sections divided by a plurality of partition plates suspended from the tank upper portion and a plurality of weirs , and a liquid from which impurity components are separated and removed in the impurity separation tank A metal material cleaning facility comprising a piping system for supplying to a circulation tank.