JP5124894B2

JP5124894B2 - Slag layer thickness or slag layer thickness and molten metal layer surface level position measuring method and apparatus

Info

Publication number: JP5124894B2
Application number: JP2001157959A
Authority: JP
Inventors: 一治花崎; 洋志岩村; 幸生寺内; 輝章梶川
Original assignee: ヘレウス・エレクトロナイト株式会社
Priority date: 2001-05-25
Filing date: 2001-05-25
Publication date: 2013-01-23
Anticipated expiration: 2021-05-25
Also published as: WO2002097378A1; TW528853B; JP2002356709A

Description

【０００１】
【発明の属する技術分野】
この発明は、スラグ層厚さまたはスラグ層厚さと溶融金属層表面レベル位置測定方法及びその測定装置に関する。
【０００２】
【従来の技術】
溶鉱炉で生成された銑鉄から鋼を精製するのに用いられる転炉等では、精製を制御するために、溶鋼の表面に浮遊しているスラグ層の厚さを測定する必要がある。このため、１本または２本の電極を用いて、溶鋼、スラグ、及び大気のインピーダンスの差異を測定することによりスラグ層の厚さを求める方法や、電磁コイルの誘導電圧が溶鋼、スラグ、及び大気でそれぞれ異なることを利用してスラグ層の厚さを求める方法が使用されている。
【０００３】
【発明が解決しようとする課題】
しかしながら、インピーダンスの差異を利用した測定方法は、電極を保持するランスのコネクタにおける接続インピーダンスが無視できず、誤差が大きいこと、また、電磁コイルを用いる方法は、電磁コイルを溶鋼に浸漬した際の損傷防止を施す必要があり、装置が大型で高価になり、それぞれ問題であった。
この発明は、このような問題点を解決するためになされたものであって、誤差が小さく、コストの低いスラグ層厚さ測定方法及びその装置を提供しようとするものである。
【０００４】
【課題を解決するための手段】
転炉等の容器に満たされた溶鋼は、溶けた金属が主成分であり、その電気的特性としては金属としての導電性を示すのに対して、溶鋼の表面に浮遊しているスラグ層は電解質であり、その中に電極を浸漬すると電池としての特性を示すことが分かってきた。また、スラグ層の上層を占める大気は、よく知られているように電気的特性としては絶縁性を有している。この発明は、これらの点に注目してなされたものであって、スラグ層が示す電気的特性が、その下層の溶鋼や上層の大気と異なることを利用して、スラグ層の厚さを測定しようとするものである。上記のスラグ層が示す電気的特性は、溶鋼に限らず、溶融金属一般に適用できるので、本発明では、溶融金属を対象としている。
【０００５】
本発明の第１のスラグ層厚さ測定方法は、具体的には、次のような方法である。
即ち、溶融金属層表面にスラグ層が浮遊する溶湯の、前記スラグ層の厚さを測定する方法であって、
前記溶融金属層から前記スラグ層を通って前記スラグ層の上層を占める大気層まで電極を上昇移動させて、前記溶湯を収容して導電性を帯びた容器と前記電極との間の電気的特性である電極−容器間特性を監視し、
この電極−容器間特性が、前記電極が前記溶融金属層に没入しているときの前記溶融金属層の介在による導電性から、前記電極が前記スラグ層へ移動して電解質として機能する前記スラグ層の介在による発電性に移行する時点である溶融金属−スラグ界面通過時点と、
前記電極が前記スラグ層から前記大気層へ脱出して、前記電極−容器間特性が、前記発電性から前記大気層の介在による絶縁性に移行する時点であるスラグ−大気界面通過時点とを検知すると共に、
前記溶融金属−スラグ界面通過時点から前記スラグ−大気界面通過時点までに、前記電極が移動した移動距離を計測して、前記スラグ層の厚さとしてなるスラグ層厚さ測定方法である。
【０００６】
図１は、この第１のスラグ層厚さ測定方法の原理を示した説明図である。図１において、１は容器、２は溶融金属層、３はスラグ層、４は大気層、５は電極である。スラグ層３は前述の通り電解質であり、その中に電極を浸漬すると化学電池としての特性を示す。これは、溶融スラグ中の陽イオン（Ｓｉ２＋，Ｐ２＋等）と陰イオン（Ｏ２−）が電極を通じて電子の授受をすることにより起電力が発生するからである。
【０００７】
この第１のスラグ層厚さ測定方法は、電極５を、溶融金属層２からスラグ層３を通って大気層４まで上昇移動させ、この間の電極５と容器１との間の電気的特性である電極−容器間特性の変化を利用して、スラグ層３の厚さを測定するものであり、図１は、この測定方法の説明図である。溶融金属を収容する転炉等の容器１は、一般に、金属製の容器の内側に耐火煉瓦を積み上げて形成されており、容器１だけでは導電性を有しないが、容器１内に溶融金属を収容することによって、容器１の内面に金属が付着することにより、容器１の内面と大地との間が導電性を有するようになる。即ち、容器が導電性を帯びるようになる。そこで、電極５と大地間の電気的特性を調べることによって、電極５と容器１との間の電気的特性である電極−容器間特性を調べることができる。
この場合、図１において、電極５が溶融金属層２に位置しているとき（ａ）は、溶融金属層２が金属の溶けた状態であるから、電極−容器間特性は導電性である。電極５がスラグ層３に移動すると（ｂ）、電極−容器間特性は上述の通り発電性となる。電極５がスラグ層３を抜けて大気層４に移動すると（ｃ）、大気が介在して電極−容器間特性は絶縁性となる。そこで、電極５を溶融金属層２から大気層４へ上昇移動させる際、電極−容器間特性が導電性から発電性に変化する溶融金属層２とスラグ層３の境界面を電極５が通過する溶融金属−スラグ界面通過時点７と、電極−容器間特性が発電性から絶縁性に変化するスラグ層３と大気層４の境界面を電極５が通過するスラグ−大気界面通過時点８とを検知し、この間に、電極５が上昇移動した距離を測定することにより、スラグ層３の厚さを知ることができる。
【０００８】
上記の第１のスラグ層厚さ測定方法では、電極５を上昇移動させているが、電極を下降移動させてもよい。この場合の第２のスラグ層厚さ測定方法は、
溶融金属層表面にスラグ層が浮遊する溶湯の、前記スラグ層の厚さを測定する方法であって、
前記スラグ層の上層を占める大気層から前記スラグ層を通って前記溶融金属層まで電極を降下移動させて、前記溶湯を収容して導電性を帯びた容器と前記電極との間の電気的特性である電極−容器間特性を監視し、
この電極−容器間特性が、前記電極が前記大気層にあるときの大気の介在による絶縁性から、前記電極が前記スラグ層に没入して電解質として機能する前記スラグ層の介在による発電性に移行する時点である大気−スラグ界面通過時点と、前記電極が前記スラグ層から前記溶融金属層へ移動して、前記電極−容器間特性が、前記発電性から前記溶融金属層の介在による導電性に移行する時点であるスラグ−溶融金属界面通過時点とを検知すると共に、
前記大気−スラグ界面通過時点から前記スラグ−溶融金属界面通過時点までに、前記電極が移動した移動距離を計測して、前記スラグ層の厚さとしてなるスラグ層厚さ測定方法である。
【０００９】
この第２のスラグ層厚さ測定方法の場合、電極を、大気層からスラグ層を通って溶融金属層まで降下移動させ、電極−容器間特性が絶縁性から発電性に変化する大気層とスラグ層の境界面を電極が通過する大気−スラグ界面通過時点と、電極−容器間特性が発電性から導電性に変化するスラグ層と溶融金属層の境界面を電極が通過するスラグ−溶融金属界面通過時点とを検知し、この間に、電極が下降移動した距離を測定することにより、電極を上昇移動させた場合と同様に、スラグ層の厚さを知ることができる。
【００１０】
上記の第１のスラグ層厚さ測定方法、または、第２のスラグ層厚さ測定方法によれば、電極と容器との間の電気的特性である電極−容器間特性の変化である、導電性、発電性、または、絶縁性の各性質相互間の変化を利用して測定を行なう。この変化は、インピーダンスの変化のような同質なもの相互間の変化ではなく、異質なもの相互間の変化であるので、変化を明瞭にとらえることができ、スラグ層の厚さを正確に測定することができる。
また、電極自身は、コスト的には高価ではないことから、測定の都度交換してよく、電極に損傷防止を施す必要がないため、これらのスラグ層厚さ測定方法によれば、コストの低いスラグ層厚さ測定方法を提供することができる。
【００１１】
上記の第１のスラグ層厚さ測定方法、及び、第２のスラグ層厚さ測定方法における、溶融金属−スラグ界面通過時点、スラグ−大気界面通過時点、大気−スラグ界面通過時点、あるいは、スラグ−溶融金属界面通過時点の検知を、前記容器に対する前記電極の電位を測定することにより行なうスラグ層厚さ測定方法が考えられる。
まず、この方法による、第３のスラグ層厚さ測定方法は、上記の第１のスラグ層厚さ測定方法において、
前記電極と前記容器との間に、前記電極側を陰極とした直流電源Ｖccとこの電源と直列接続された抵抗Ｒｘを挿入し、且つ、前記直流電源Ｖccと前記抵抗Ｒｘの値を、前記電極が前記スラグ層に没入しているときに、前記容器の電位を基準電位とした前記電極の電位が前記基準電位よりも高い高電位となるように設定すると共に、
前記電極を前記溶融金属層から前記大気層まで上昇移動させて、前記基準電位に対する前記電極の電位を測定し、
前記溶融金属−スラグ界面通過時点として、前記電極の電位が前記基準電位から前記高電位へ変化する時点を、
また、前記スラグ−大気界面通過時点として、前記電極の電位が前記高電位から前記基準電位よりも低い低電位へ変化する時点を、
検知してなるスラグ層厚さ測定方法である。
【００１２】
図２は、この第３のスラグ層厚さ測定方法に用いられる測定装置の構成を示した説明図である。図２は、図１の電極５と容器１との間に、電極５側を陰極とした直流電源Ｖcc１１と、この電源１１と直列接続された抵抗Ｒｘ１２を挿入し、容器１に対する電極５の電位、即ち、電極５と容器１との間の電圧を測定する電位測定手段１３を設けたものである。ここで、直流電源１１と抵抗Ｒｘ１２の値は、電極がスラグ層に没入しているときに、容器１の電位を基準電位とした電極５の電位が、基準電位よりも高い電位となるように設定されている。
【００１３】
図３は、図２の等価回路を示したものである。図２において、電極５が、溶融金属層２、スラグ層３または大気層４の間を移動することは、電気的に見ると、図３の切換スイッチ１９を切り換えるのと同じである。即ち、電極５が溶融金属層２に位置しているとき（ａ）は、溶融金属層２が、金属の溶けた状態であるから、電極−容器間特性は導電性であるので、電極５と容器１との間は溶融金属層２を介した短絡状態となる。電極５がスラグ層３に位置しているとき（ｂ）は、スラグ層３が電解質であることから電池特性を示して、電極５と容器１との間に、スラグ層３の代わりに、起電力がＥｏで内部抵抗がＲｏの電池が接続されているのと同じになる。電極５が大気層４に位置しているとき（ｃ）は、大気が絶縁性を有するから、電極５と容器１との間は、大気層４を介して開放されていることになる。これらの各場合の等価回路を、図４の（ａ）から（ｃ）に示す。
即ち、図２において、容器１の電位を基準電位０（Ｖ）として、電極５が溶融金属層２に位置しているとき（ａ）、スラグ層３に位置しているとき（ｂ）、あるいは、大気層４に位置しているとき（ｃ）の、それぞれの基準電位に対する電極５の電位を、Ｖａ、Ｖｂ、Ｖｃとすると、これらは、それぞれ図４の（ａ）から（ｃ）に示すように、Ｖａ＝０（Ｖ）（基準電位）、Ｖｂ＝（ＥｏＲｘ−ＶccＲｏ）／（Ｒｏ＋Ｒｘ）（Ｖ）、Ｖｃ＝−Ｖcc（Ｖ）（基準電位よりも低い低電位）となる。ここで、図４（ｂ）のＶｂは、前述した直流電源Ｖccと抵抗Ｒｘの値の設定により、基準電位である容器１の電位に対して、この基準電位よりも高い高電位であり、図４（ｂ）のアースに対してプラス電位となる。一般には、Ｒｘは数百キロオーム台、スラグ層３が示す電池特性における内部抵抗Ｒｏは数十から数百オーム程度であることから、図４（ｂ）に示すように、ＶｂはＥｏにほぼ等しくなる。この起電力は、アースに対して陽極性であるので、Ｖｂはプラス電位となる。
【００１４】
上記の測定回路を用いて、電極５を、溶融金属層２からスラグ層３を通って大気層４まで上昇移動させた場合の、容器１の電位を基準電位とした電極５の電位を測定すると、図５のようになる。Ｔａ時点で測定を開始し、電極５が溶融金属層２に位置しているとき（ａ）は、Ｖａで０（Ｖ）である。電極５が溶融金属層２からスラグ層３に移行するＴｂ時点、即ち、溶融金属−スラグ界面通過時点では、Ｖｂでプラス電位となる。さらに、接触子５がスラグ層３から大気層４に移行するＴｃ時点、即ち、スラグ−大気界面通過時点では、Ｖｃで−Ｖcc（Ｖ）となり、マイナス電位となる。
そうすると、電極５の電位が０（Ｖ）からプラス電位に変化した時点、即ち、基準電位からこの基準電位よりも高い高電位へ変化した時点を検知すれば、溶融金属−スラグ界面通過時点を検知したことになり、電極５の電位が、プラス電位からマイナス電位に変化した時点、即ち、基準電位よりも高い高電位から基準電位よりも低い低電位へ変化した時点を検知すればスラグ−大気界面通過時点を検知したことになる。
そこで、これらの検知を基に、溶融金属−スラグ界面通過時点からスラグ−大気界面通過時点までに、電極５が移動した移動距離を求めることにより、スラグ層３の厚さを知ることができる。
【００１５】
上記の第３のスラグ層厚さ測定方法では、電極を上昇移動させているが、電極を下降移動させた場合についても、同様の原理で測定することができる。この場合の第４のスラグ層厚さ測定方法は、上記の第２のスラグ層厚さ測定方法において、
前記電極と前記容器との間に、前記電極側を陰極とした直流電源Ｖccとこの電源と直列接続された抵抗Ｒｘを挿入し、且つ、前記直流電源Ｖccと前記抵抗Ｒｘの値を、前記電極が前記スラグ層に没入しているときに、前記容器の電位を基準電位とした前記電極の電位が、前記基準電位よりも高い高電位となるように設定すると共に、
前記電極を前記大気層から前記溶融金属層まで降下移動させて、前記基準電位に対する前記電極の電位を測定し、
前記大気−スラグ界面通過時点として、前記電極の電位が前記基準電位よりも低い低電位から前記高電位へ変化する時点を、
また、前記スラグ−溶融金属界面通過時点として、前記電極の電位が前記高電位から前記基準電位へ変化する時点を、
検知してなるスラグ層厚さ測定方法である。
【００１６】
上記の第３のスラグ層厚さ測定方法、または、第４のスラグ層厚さ測定方法によれば、電極の電位の変化が、基準電位と、この基準電位よりも高い高電位と、この基準電位よりも低い低電位のいずれかへの変化であり、変化をデジタル的にとらえることができるので、変化の検知を正確に行なうことができ、これらの検知を基にして、電極の移動距離を正確に求めることができることから、スラグ層の厚さを正確に知ることができる。
また、電極に接続されたコネクタなどの接触抵抗により、電極と容器との間のインピーダンスが変化しても、電極の電位の変化は、基準電位と、この基準電位よりも高い高電位と、この基準電位よりも低い低電位のいずれかへの変化であることに変わりはないので、上記の測定方法は、電極と容器との間のインピーダンスの変化の影響を受けにくい方法といえる。
【００１７】
上記の第１、第２、第３、または第４のスラグ層厚さ測定方法では、電極の移動距離を直接測定しているが、前記電極の移動速度を一定とし、前記大気−スラグ界面通過時点から前記スラグ−溶融金属界面通過時点まで、あるいは、前記溶融金属−スラグ界面通過時点から前記スラグ−大気界面通過時点までの、前記電極の移動時間を測定し、この移動時間と電極の移動速度から、演算で電極の移動距離を求めるようにしてもよい。
即ち、第５のスラグ層厚さ測定方法として、上記の第１、第２、第３、または第４のスラグ層厚さ測定方法において、
前記電極の上昇移動または降下移動の移動速度を一定とすると共に、
前記電極を前記溶融金属層から前記大気層まで上昇移動させる方法を用いた場合は、前記溶融金属−スラグ界面通過時点から前記スラグ−大気界面通過時点までの、前記電極の移動時間を計測し、
前記電極を前記大気層から前記溶融金属層まで降下移動させる方法を用いた場合は、前記大気−スラグ界面通過時点から前記スラグ−溶融金属界面通過時点までの、前記電極の移動時間を計測し、
前記電極の前記移動距離を計測するのに代えて、
前記電極の前記移動速度と前記移動時間から、演算により前記電極の前記移動距離を求めてなるスラグ層厚さ測定方法が存在する。
【００１８】
この方法によれば、電極の移動距離を直接測定する必要がなく、測定方法が簡便になる。
【００１９】
次に、本発明のスラグ層厚さ測定装置について説明する。まず、第１のスラグ層厚さ測定装置は、
電極と、
溶融金属層表面にスラグ層が浮遊する溶湯を収容して導電性を帯びた容器と、前記電極を前記溶融金属層から前記スラグ層を通って前記スラグ層の上層を占める大気層まで上昇移動させ、あるいは、前記大気層から前記スラグ層を通って前記溶融金属層まで降下移動させる電極移動手段と、
前記電極と前記容器との間に、前記電極側を陰極とした直流電源Ｖccとこの電源と直列接続された抵抗Ｒｘを挿入すると共に、前記直流電源Ｖccと前記抵抗Ｒｘの値を、前記電極が前記スラグ層に没入しているときに、前記容器の電位を基準電位として、前記電極の電位が前記基準電位よりも高い電位となるように設定して形成された測定回路と、
前記基準電位に対する前記電極の電位を測定する電位測定手段と、
前記電位測定手段が検知した、前記基準電位から前記高電位へ変化する時点から、前記高電位から前記基準電位よりも低い低電位へ変化する時点までの、あるいは、前記低電位から前記高電位へ変化する時点から、前記高電位から前記基準電位へ変化する時点までの、前記電極の移動距離を計測する電極移動距離計測手段と、
で構成されてなるスラグ層厚さ測定装置である。
【００２０】
この第１のスラグ層厚さ測定装置は、電極を溶融金属層からスラグ層を通ってスラグ層の上層を占める大気層まで上昇移動させる場合は、電位測定手段が、溶湯を収容する容器と電極との間の電極−容器間特性が、導電性から発電性へ移行する溶融金属−スラグ界面通過時点として、電極の電位が、基準電位から基準電位より高い高電位へ変化する時点を検知すると共に、発電性から絶縁性へ移行するスラグ−大気界面通過時点として、電極の電位が、高電位から基準電位より低い低電位へ変化する時点を検知する。そして、電極移動距離計測手段が、溶融金属−スラグ界面通過時点からスラグ−大気界面通過時点までの間の電極の移動距離を求めて、スラグ層の厚さとする。
また、大気層からスラグ層を通って溶融金属層まで、電極を降下移動させる場合は、電位測定手段が、溶湯を収容する容器と電極との間の電極−容器間特性が、電極が大気層にあるときの大気の介在による絶縁性から、電解質として機能するスラグ層に没入して発電性に移行する大気−スラグ界面通過時点として、電極の電位が、基準電位より低い低電位から基準電位より高い高電位へ変化する時点を検知すると共に、電極−容器間特性が、発電性から、電極が溶融金属層へ没入して導電性に移行するスラグ−溶融金属界面通過時点として、電極の電位が、高電位から基準電位へ変化する時点を検知する。そして電極移動距離計測手段が、大気−スラグ界面通過時点からスラグ−溶融金属界面通過時点までの間の電極の移動距離を求め、これをスラグ層の厚さとする。
【００２１】
即ち、この装置は、上述の第３のスラグ層厚さ測定方法、または、第４のスラグ層厚さ測定方法に基づいて、スラグ層の厚さを求める装置であり、その作用、効果は、上述の第３のスラグ層厚さ測定方法、または、第４のスラグ層厚さ測定方法と同様であるので、説明を省略する。
【００２２】
上記の第１のスラグ層厚さ測定装置では、電極の移動距離を、直接測定する電極移動距離計測手段により求めているが、電極の移動速度と移動時間とから、演算により求める第２のスラグ層厚さ測定装置も考えられる。この第２のスラグ層厚さ測定装置は、
電極と、
溶融金属層表面にスラグ層が浮遊する溶湯を収容して導電性を帯びた容器と、
移動速度を一定として、前記電極を、前記溶融金属層から前記スラグ層を通って前記スラグ層の上層を占める大気層まで上昇移動させ、あるいは、前記大気層から前記スラグ層を通って前記溶融金属層まで、降下移動させる電極移動手段と、
前記電極と前記容器との間に、前記電極側を陰極とした直流電源Ｖccと、この電源と直列接続された抵抗Ｒｘを挿入すると共に、前記直流電源Ｖccと前記抵抗Ｒｘの値を、前記電極が前記スラグ層に没入しているときに、前記容器の電位を基準電位として、前記電極の電位が前記基準電位よりも高い電位となるように設定して形成された測定回路と、
前記基準電位に対する前記電極の電位を測定する電位測定手段と、
前記電位測定手段が検知した、前記基準電位から前記高電位へ変化する時点から、前記高電位から前記基準電位よりも低い低電位へ変化する時点までの、あるいは、前記低電位から前記高電位へ変化する時点から、前記高電位から前記基準電位へ変化する時点までの、前記電極の移動時間を計測する電極移動時間計測手段と、
前記電極の前記移動速度と前記移動時間とから、演算により前記電極の移動距離を求める電極移動距離演算手段と、
で構成されてなるスラグ層厚さ測定装置である。
【００２３】
この第２のスラグ層厚さ測定装置は、電極の移動距離を、電極の移動速度と移動時間とから、演算により求めるので、第５のスラグ層厚さ測定方法と同様の効果を有する。また、電極の移動距離を、電極の移動速度と移動時間とから、演算により求めること以外は、上記の第１のスラグ層厚さ測定装置と全く同じ構成であり、その作用、効果も上記の第１のスラグ層厚さ測定装置と全く同じである。
【００２４】
上記の第２のスラグ層厚さ測定装置において、電極の移動速度を、２個の電極を用いて測定する第３のスラグ層厚さ測定装置が考えられる。この第３のスラグ層厚さ測定装置は、上記の第２のスラグ層厚さ測定装置において、
前記電極に加えて、電極を１個追加すると共に、これらの２個の電極の下端を、その移動方向に一定距離だけ離して設けると共に、
これらの電極を２個同時に移動させることにより、前記容器に対する２個の各前記電極の検知する電位の時間的ずれを測定すると共に、この時間的ずれと前記一定距離とから前記移動速度を求める移動速度検出手段を設けてなるスラグ層厚さ測定装置である。
【００２５】
図６（ａ）は、この第３のスラグ層厚さ測定装置に用いられる移動速度検出手段の速度検出原理の説明図である。図６（ａ）において、電極２２の下端は電極２１の下端よりも、移動方向である上方向に距離Ｄだけ離して設けられており、電極２１及び電極２２はそれぞれ測定装置２３の第Ｉ入力及び第２入力に接続されている。また、測定装置２３における、容器１に対する電極２１、２２の電位の測定方法は、前述の電極の電位測定方法と同様の方法を用いる。そこで、電極２１、２２を２個同時に、溶融金属層２からスラグ層３を通って大気層４まで上昇移動させると、電極２１、２２の電位は、図６（ｂ）のように、第Ｉ入力と第２入力とでは、Ｔだけずれることになる。そうすると、電極２１、２２の上昇移動速度Ｓは、Ｓ＝Ｄ／Ｔで求められる。
このスラグ層厚さ測定装置によれば、電極の移動速度を予め定めておく必要がない。
【００２６】
上述した第１のスラグ層厚さ測定装置から第３のスラグ層厚さ測定装置は、溶融金属を対象としているが、溶融金属として溶鋼を用いることができる。
【００２７】
溶融金属として溶鋼を用いたスラグ層厚さ測定装置では、これに使用される電極の材質を、Mo、Co、Cr、Mnの中から、少なくとも一つを含む鉄の合金とすることが推奨される。上述したスラグ層厚さ測定装置では、容器内の溶湯が高温であり、この溶湯に浸漬した電極は、時間がたつと溶融してしまう。そこで、溶融するまでの時間をできるだけ長くすることが望ましいが、この点で、上記の合金は溶融しにくく、電極の材質として優れている。
【００２８】
上述した各スラグ層厚さ測定装置において、スラグ層の厚さを測定する際、酸素濃度の測定が必要な場合に、電極を酸素プローブの溶鋼電極と併用して用いるようにしても良い。このようにすることにより、同時に、スラグ層の厚さの測定と、酸素濃度の測定を行なうことができると共に、電極を併用できるので、測定装置のコスト低減を図ることができる。
【００２９】
また、上記のスラグ層厚さ測定装置において、酸素プローブの溶鋼電極と併用する電極と、酸素プローブのジルコニア極との下部先端位置をそろえると共に、双方の先端部分以外の部分を石英管等の防護用パイプで覆って用いるようにしても良い。このようにすることにより、電極と、酸素プローブのジルコニア極の双方に対して、スラグが付着するのを防止でき、また、同時に、スラグ層の厚さの測定と、酸素濃度の測定を行なうことができると共に、電極を併用できるので、測定装置のコスト低減を図ることができる。
【００３０】
また、上述した各スラグ層厚さ測定装置において、電極を溶鋼温度測定プローブへ取り付けて用いるようにしても良い。このようにすることにより、同時に、スラグ層の厚さの測定と、溶鋼温度の測定を行なうことができると共に、電極を併用できるので、測定装置のコスト低減を図ることができる。
【００３１】
ところで、転炉等の溶融金属を収容した容器では、下部に浸漬管を備えた真空槽を溶融金属上に浮遊するスラグの上方に配設すると共に、浸漬管を溶融金属内に浸漬させ、真空槽内に溶融金属を取り込んで、Ｃａ等を加えて、溶融金属中のスラグ成分の粒子を凝集させることにより、溶融金属中のスラグ成分を取り除きやすくしている。この場合、浸漬管を水冷する必要があり、この冷却水と溶融金属とが触れると爆発を生じる恐れがあるので、真空槽の溶融金属層表面からの高さの位置制御が必要であり、このため、溶融金属層の表面レベル位置を測定する必要がある。
上述した説明は、スラグ層厚さ測定方法またはその装置に関するものであるが、これに用いられている原理は、スラグ層厚さの測定のみならず、溶融金属層の表面レベル位置の測定にも使用することができるので、次に、スラグ層厚さの測定と共に、溶融金属層の表面レベル位置、即ち、溶湯を収容した容器の開口部上方で、容器から予め定められた一定距離離れて位置する定点から溶融金属層の表面までの距離の測定を行なう方法について述べる。
【００３２】
この方法における、第１のスラグ層厚さ及び溶融金属層表面レベル位置測定方法は、
溶融金属層表面にスラグ層が浮遊する溶湯を収容して導電性を帯びた容器の開口部上方で、前記容器から予め定められた一定距離離れて位置する定点から前記溶融金属層の表面までの距離、及び、前記スラグ層の厚さを測定する方法であって、
前記溶融金属層から前記スラグ層を通って前記スラグ層の上層を占める大気層中の前記定点まで電極を上昇移動させて、前記容器と前記電極との間の電気的特性である電極−容器間特性を監視し、
この電極−容器間特性が、前記電極が前記溶融金属層に没入しているときの前記溶融金属層の介在による導電性から、前記電極が前記スラグ層へ移動して電解質として機能する前記スラグ層の介在による発電性に移行する時点である溶融金属−スラグ界面通過時点と、
前記電極が前記スラグ層から前記大気層へ脱出して、前記電極−容器間特性が、前記発電性から、前記大気層の介在による絶縁性に移行する時点であるスラグ−大気界面通過時点とを検知すると共に、
前記溶融金属−スラグ界面通過時点から前記スラグ−大気界面通過時点までに、前記電極が移動した移動距離を計測して、前記スラグ層の厚さとすると共に、前記溶融金属−スラグ界面通過時点から前記定点までに、前記電極が移動した移動距離を計測して、前記定点から前記溶融金属層の表面までの距離としてなるスラグ層厚さ及び溶融金属層表面レベル位置測定方法である。
【００３３】
図７は、上記の方法の測定原理を示した説明図である。上記の方法では、図７において、溶融金属層表面にスラグ層が浮遊する溶湯を収容して導電性を帯びた容器１の開口部上方で、容器１から予め定められた一定距離離れた位置を、定点９とし、電極５を、溶融金属層からスラグ層を通ってスラグ層の上層を占める大気層中の定点９まで電極を上昇移動させて、この間の電極５と容器１との間の電気的特性である電極−容器間特性の変化を利用して、スラグ層の厚さ６及び、定点９から溶融金属層２の表面までの距離１０を測定するものである。上記の方法では、スラグ層の厚さ６の測定方法は、第１のスラグ層厚さ測定方法と全く同じである。また、定点９から溶融金属層２の表面までの距離１０の測定に用いられる溶融金属−スラグ界面通過時点７の検知方法も第１のスラグ層厚さ測定方法と全く同じであり、この溶融金属−スラグ界面通過時点７から定点９に至るまで電極５が移動した距離を測定することにより定点９から溶融金属層２の表面までの距離１０を求めることができる。
【００３４】
上記の方法では、電極５を上昇移動させているが、電極を下降移動させてもよい。また、上記で述べたとおり、図７において、溶融金属層の表面レベル位置の測定は、即ち、定点９から溶融金属層２の表面までの距離１０を測定することである。ここでいう定点から溶融金属層の表面までの距離を求めることは、溶融金属−スラグ界面通過時点から定点に至るまで、あるいは、定点からスラグ−溶融金属界面通過時点に至るまでに、電極５が移動した距離または時間を測定することで行なうことができ、溶融金属−スラグ界面通過時点あるいはスラグ−溶融金属界面通過時点の検知は、上述した各スラグ層厚さ測定方法において使用されている検知方法がそのまま使用できる。そこで、第２、第３、第４、または第５のスラグ層厚さ及び溶融金属層表面レベル位置測定方法、あるいは、第１、または第２のスラグ層厚さ及び溶融金属層表面レベル位置測定装置として、上述した各スラグ層厚さ測定方法あるいは上述した各スラグ層厚さ測定装置を応用することにより、以下に示す方法及び装置が考えられる。
【００３５】
第２のスラグ層厚さ及び溶融金属層表面レベル位置測定方法は、
溶融金属層表面にスラグ層が浮遊する溶湯を収容して導電性を帯びた容器の開口部上方で、前記容器から予め定められた一定距離離れて位置する定点から前記溶融金属層の表面までの距離、及び、前記スラグ層の厚さを測定する方法であって、
前記スラグ層の上層を占める大気層中の前記定点から前記スラグ層を通って前記溶融金属層まで、電極を降下移動させて、前記溶湯を収容して導電性を帯びた容器と、前記電極との間の電気的特性である電極−容器間特性を監視し、
この電極−容器間特性が、前記電極が前記大気層にあるときの大気の介在による絶縁性から、前記電極が前記スラグ層に没入して電解質として機能する前記スラグ層の介在による発電性に移行する時点である大気−スラグ界面通過時点と、
前記電極が前記スラグ層から前記溶融金属層へ移動して、前記電極−容器間特性が、前記発電性から、前記溶融金属層の介在による導電性に移行する時点であるスラグ−溶融金属界面通過時点とを検知すると共に、
前記定点から前記スラグ−溶融金属界面通過時点までに、前記電極が移動した移動距離を計測して、前記定点から前記溶融金属層の表面までの距離とすると共に、
前記大気−スラグ界面通過時点から前記スラグ−溶融金属界面通過時点までに、前記電極が移動した移動距離を計測して、前記スラグ層の厚さとしてなるスラグ層厚さ及び溶融金属層表面レベル位置測定方法である。
【００３６】
第３のスラグ層厚さ及び溶融金属層表面レベル位置測定方法は、第１のスラグ層厚さ及び溶融金属層表面レベル位置測定方法において、
前記電極と前記容器との間に、前記電極側を陰極とした直流電源Ｖccと、この電源と直列接続された抵抗Ｒｘを挿入し、且つ、前記直流電源Ｖccと前記抵抗Ｒｘの値を、前記電極が前記スラグ層に没入しているときに、前記容器の電位を基準電位とした前記電極の電位が、前記基準電位よりも高い高電位となるように設定すると共に、
前記電極を前記溶融金属層から前記大気層まで上昇移動させて、前記基準電位に対する前記電極の電位を測定し、
前記溶融金属−スラグ界面通過時点として、前記電極の電位が、前記基準電位から前記高電位へ変化する時点を、
また、前記スラグ−大気界面通過時点として、前記電極の電位が、前記高電位から前記基準電位よりも低い低電位へ変化する時点を、
検知してなるスラグ層厚さ及び溶融金属層表面レベル位置測定方法である。
【００３７】
第４のスラグ層厚さ及び溶融金属層表面レベル位置測定方法は、第２のスラグ層厚さ及び溶融金属層表面レベル位置測定方法において、
前記電極と前記容器との間に、前記電極側を陰極とした直流電源Ｖccと、この電源と直列接続された抵抗Ｒｘを挿入し、且つ、前記直流電源Ｖccと前記抵抗Ｒｘの値を、前記電極が前記スラグ層に没入しているときに、前記容器の電位を基準電位とした前記電極の電位が、前記基準電位よりも高い高電位となるように設定すると共に、
前記電極を前記大気層から前記溶融金属層まで降下移動させて、前記基準電位に対する前記電極の電位を測定し、
前記大気−スラグ界面通過時点として、前記電極の電位が、前記基準電位よりも低い低電位から前記高電位へ変化する時点を、
また、前記スラグ−溶融金属界面通過時点として、前記電極の電位が、前記高電位から前記基準電位へ変化する時点を、
検知してなるスラグ層厚さ及び溶融金属層表面レベル位置測定方法である。
【００３８】
第５のスラグ層厚さ及び溶融金属層表面レベル位置測定方法は、第１、第２、第３、または第４のスラグ層厚さ及び溶融金属層表面レベル位置測定方法において、
前記電極の上昇移動または降下移動の移動速度を一定とすると共に、
前記電極を前記溶融金属層から前記大気層まで上昇移動させる方法を用いた場合は、
前記スラグ層の厚さ算出用として、前記溶融金属−スラグ界面通過時点から前記スラグ−大気界面通過時点までの、前記電極の移動時間を計測し、
前記定点から前記溶融金属層の表面までの距離算出用として、前記溶融金属−スラグ界面通過時点から前記定点までの、前記電極の移動時間を計測し、
前記電極を前記大気層から前記溶融金属層まで降下移動させる方法を用いた場合は、
前記定点から前記溶融金属層の表面までの距離算出用として、前記定点から前記スラグ−溶融金属界面通過時点までの、前記電極の移動時間を計測し、
前記スラグ層の厚さ算出用として、前記大気−スラグ界面通過時点から前記スラグ−溶融金属界面通過時点までの、前記電極の移動時間を計測し、
前記電極の各前記移動距離を計測するのに代えて、
前記電極の前記移動速度と各前記移動時間とから、演算により前記電極の各前記移動距離を求めてなるスラグ層厚さ及び溶融金属層表面レベル位置測定方法である。
【００３９】
第１のスラグ層厚さ及び溶融金属層表面レベル位置測定装置は、
電極と、
溶融金属層表面にスラグ層が浮遊する溶湯を収容して導電性を帯びた容器と、
前記電極を、前記溶融金属層から、前記スラグ層を通って前記スラグ層の上層を占める大気層中の、前記容器の開口部上方で、前記容器から予め定められた一定距離離れて位置する定点まで上昇移動させ、あるいは、前記大気層中の前記定点から、前記スラグ層を通って前記溶融金属層まで、降下移動させる電極移動手段と、
前記電極と前記容器との間に、前記電極側を陰極とした直流電源Ｖccと、この電源と直列接続された抵抗Ｒｘを挿入すると共に、前記直流電源Ｖccと前記抵抗Ｒｘの値を、前記電極が前記スラグ層に没入しているときに、前記容器の電位を基準電位として、前記電極の電位が前記基準電位よりも高い電位となるように設定して形成された測定回路と、
前記基準電位に対する前記電極の電位を測定する電位測定手段と、
前記スラグ層の厚さ測定用として、前記電位測定手段が検知した、前記基準電位から前記高電位へ変化する時点から、前記高電位から前記基準電位よりも低い低電位へ変化する時点までの、あるいは、前記低電位から前記高電位へ変化する時点から、前記高電位から前記基準電位へ変化する時点までの、前記電極の移動距離を計測するスラグ層厚さ測定用電極移動距離計測手段と、
前記定点から前記溶融金属層の表面までの距離測定用として、前記電位測定手段が検知した前記基準電位から前記高電位へ変化する時点から前記定点までの、あるいは、前記定点から、前記高電位から前記基準電位へ変化する時点までの、前記電極の移動距離を計測する溶融金属層表面レベル位置測定用電極移動距離計測手段と、
で構成されてなるスラグ層厚さ及び溶融金属層表面レベル位置測定装置である。
【００４０】
そして、第２のスラグ層厚さ及び溶融金属層表面レベル位置測定装置は、
電極と、
溶融金属層表面にスラグ層が浮遊する溶湯を収容して導電性を帯びた容器と、
前記電極を、移動速度を一定として、前記溶融金属層から、前記スラグ層を通って前記スラグ層の上層を占める大気層中の、前記容器の開口部上方で、前記容器から予め定められた一定距離離れて位置する定点まで上昇移動させ、あるいは、前記大気層中の前記定点から、前記スラグ層を通って前記溶融金属層まで降下移動させる電極移動手段と、
前記電極と前記容器との間に、前記電極側を陰極とした直流電源Ｖccと、この電源と直列接続された抵抗Ｒｘを挿入すると共に、前記直流電源Ｖccと前記抵抗Ｒｘの値を、前記電極が前記スラグ層に没入しているときに、前記容器の電位を基準電位として、前記電極の電位が前記基準電位よりも高い電位となるように設定して形成された測定回路と、
前記基準電位に対する前記電極の電位を測定する電位測定手段と、
前記スラグ層の厚さ測定用として、前記電位測定手段が検知した、前記基準電位から前記高電位へ変化する時点から、前記高電位から前記基準電位よりも低い低電位へ変化する時点までの、あるいは、前記低電位から前記高電位へ変化する時点から、前記高電位から前記基準電位へ変化する時点までの、前記電極の移動時間を計測するスラグ層厚さ測定用電極移動時間計測手段と、
前記定点から前記溶融金属層の表面までの距離測定用として、前記電位測定手段が検知した、前記基準電位から前記高電位へ変化する時点から前記定点までの、あるいは、前記定点から、前記高電位から前記基準電位へ変化する時点までの、前記電極の移動時間を計測する溶融金属層表面レベル位置測定用電極移動時間計測手段と、
前記電極の前記移動速度と各前記移動時間とから、演算により前記電極の移動距離を求める電極移動距離演算手段と、
で構成されてなるスラグ層厚さ及び溶融金属層表面レベル位置測定装置である。
【００４１】
上記の各スラグ層厚さ及び溶融金属層表面レベル位置測定方法、あるいは、スラグ層厚さ及び溶融金属層表面レベル位置測定装置によれば、上述のスラグ層厚さ測定方法またはスラグ層厚さ測定装置に使用される原理を用いることにより、スラグ層厚さの測定のみならず、スラグ層の表面レベル位置を測定することができる。
【００４２】
【発明の実施の形態】
次に、本発明の実施例につき、図面に基づき詳しく説明する。本発明は、溶融金属を対象とするものであるが、本発明の第１実施例であるスラグ層厚さ測定装置では溶融金属として、溶鋼を用いている。
図８は、第１実施例であるスラグ層厚さ測定装置の構成を示した説明図である。図８において、３１は転炉、３２は溶鋼層、３３はスラグ層、３４は大気層、３５は電極、３６はプローブ、３７はランス、３８はランス移動装置、３９はエンコーダ、４０ａは計測装置、４１は直流電源Ｖcc、４２は抵抗Ｒｘ、４３は電極電位測定回路(アナログ回路)、４４はランス移動制御回路、４５はエンコーダパルスカウント回路、４７はマイクロコンピュータ、そして、４８はディスプレイである。
本第１実施例では、溶鋼を収容する容器として転炉を用いているが、取鍋を使用してもよい。
【００４３】
図８において、電極３５は、プローブ３６に保持されており、このプローブ３６を固定しているランス３７をランス移動装置３８により、垂直方向上下に移動させることによって、電極３５を移動させる仕組みとしている。ランス移動装置３８は、パルスモータやサーボモータ等位置決め制御可能なモータ等と、ラックとピニヨンによる回転運動を直線運動に変換する装置等で構成されている。
このような構成のランス移動装置３８を用いる代わりに、図１２に示すような送りねじ機構を用いるようにしてもよい。図１２では、紙製のプローブをランスの代用として用いるとともに、このプローブを回転させることによって、上下に移動させる仕組としている。
【００４４】
図９は、図８の、電極３５、プローブ３６、及びランス３７の接合部分の構造を示したものである。図９において、電極３５はプローブ３６の接触コンタクト５１に接続され、この接触コンタクト５１と接触しているリング接触子５２が電極電位測定回路(アナログ回路)４３へ接続されている。プローブ３６は、溶融した高温の溶鋼に対しては、測定に必要な短時間しか耐えることができず、測定の都度交換する必要があり、このような構造が採用されている。
図８において、転炉３１は、一般に、金属製の容器の内側に耐火煉瓦を積み上げて形成されており、転炉３１だけでは導電性を有しないが、転炉３１内に溶鋼を収容することによって、転炉３１の内面に金属が付着することにより、転炉３１の内面と大地との間が導電性を有するようになる。即ち、転炉３１が大地にアースされたのと等価となる。
また、アースと電極３５との間には、電極３５側を陰極とした直流電源Ｖcc１１と、この直流電源１１と直列接続された抵抗Ｒｘ１２接続されている。ここで、直流電源１１と抵抗Ｒｘ１２の値は、電極３５がスラグ層３３に没入しているときに、アースと同電位の転炉３１に対する電極５の電位が、プラス電位となるように設定されている。具体的には、前述したように、抵抗Ｒｘ１２は、スラグ層３３が示す化学電池特性における内部抵抗に比べて、極端に大きな値に設定され、例えば、スラグ層３３が示す電池特性における内部抵抗は数十から数百オーム程度であるのに対して、抵抗Ｒｘ１２は数百キロオーム台に設定される。その結果、前述したように、電極３５とアース間の電位は、スラグ層３３が示す化学電池特性における起電力にほぼ等しくなる。この起電力は、アースに対して陽極性であるので、電極３５の電位はプラス電位となる。
電極電位測定回路(アナログ回路)４３は、アース電位である転炉３１の電位を基準電位とした電極３５の電位を測定する回路である。エンコーダ３９はランス移動装置３８と連動しており、ランス３７が上下に移動した際に移動距離を測定するためのパルスを発生し、このパルスを、エンコーダパルスカウント回路４５がカウントすることにより、ランス３７の移動距離を求める。
このエンコーダ３９を用いる代わりに、ランスの側面上移動方向に凹凸または白黒で等間隔の縞模様状スケールを備えるとともに、光源と光センサを用いて、ランスの移動に伴って、凹凸または白黒の縞模様の変化を検知、カウントして、ランスの移動距離を測定する方法も考えられる。
【００４５】
上記の図８の測定装置において、電極３５を大気層３４からスラグ層３３を通って溶鋼層３２まで降下移動させるか、これとは逆に、溶鋼層３２からスラグ層３３を通って大気層３４まで上昇移動させ、この間の電極３５と容器である転炉３１との間の電気的特性である電極−容器間特性の変化を利用して、スラグ層３３の厚さを測定するが、本第１実施例では、溶鋼層３２からスラグ層３３を通って大気層３４まで上昇移動させてスラグ層３３の厚さを測定する。
この場合の、アースと同電位の転炉３１の電位を基準電位とした電極３５の電位の変化は、前述した図５のようになる。
図５において、Ｔａ時点で測定を開始し、電極３５が溶鋼層３２に位置しているとき（ａ）は、Ｖａで０（Ｖ）である。電極３５が溶鋼層３２からスラグ層３３に移行するＴｂ時点、即ち、溶鋼−スラグ界面通過時点では、Ｖｂでプラス電位となる。さらに、電極３５がスラグ層３３から大気層３４に移行するＴｃ時点、即ち、スラグ−大気界面通過時点では、Ｖｃで−Ｖcc（Ｖ）となり、マイナス電位となる。そこで、電極３５の移動した距離、即ち、ランス３７の移動した距離を、エンコーダパルスカウント回路４５でカウントすると共に、電極３５の電位が、０（Ｖ）からプラス電位に変化する時点と、プラス電位からマイナス電位に変化する時点を、電極電位測定回路(アナログ回路)４３で検知し、この間のエンコーダパルスカウント回路４５および、電極電位測定回路(アナログ回路)４３の出力信号がマイクロコンピュータ４７へ入力されて、スラグ層の厚さが求められ、その状況がディスプレイ４８で表示される。
【００４６】
上記の測定装置では、エンコーダ３９の出力するパルスを用いて、電極３５の移動距離を直接求めているが、電極の移動速度と移動時間とから、演算により求める方法もある。この方法では、図８から、エンコーダ３９とエンコーダパルスカウント回路４５を外すと共に、電極３５の移動速度をあらかじめ定めた一定速度とし、電極電位測定回路(アナログ回路)４３で溶鋼−スラグ界面通過時点とスラグ−大気界面通過時点とが検知され、個の信号がマイクロコンピュータ４７へ入力される。そして、このマイクロコンピュータ４７が、電極３５の移動時間を求め、この移動時間と電極３５の移動速度から電極３５の移動距離を演算して、スラグ層の厚さを求める。
この方法では、電極の移動速度をあらかじめ定め、この移動速度を演算に使用してスラグ層の厚さを求めているが、電極の移動速度をあらかじめ定めないで、電極の移動速度を、前述したように、図６に示すような２個の電極を用いて測定するようにしてもよい。
【００４７】
電極３５の移動時間と移動速度から、その移動距離を求める方法の場合も、アースと同電位の転炉３１の電位を基準電位とした電極３５の電位の変化は、前述した図５のようになる。この方法を用いたスラグ層厚さ測定装置において、この測定装置の備えるディスプレイでこの電位の変化を表示させると共に、スラグ層の厚さの演算結果を表示させることもできる。図１０は、この場合のスラグ層厚さ測定装置における表示例を示したものである。また、図１１（ａ）、（ｂ）、（ｃ）、（ｄ）は、共に、このような場合の、電極３５の電位の変化の例を示したものである。
【００４８】
上記の測定装置では、電極３５を、溶鋼層３２からスラグ層３３を通って大気層３４まで上昇移動させているが、電極３５を、大気層３４からスラグ層３３を通って溶鋼層３２まで下降移動させても、同様にスラグ層３３の厚さを知ることができる。
また、上記の測定装置では、電極３５を、垂直方向上下に移動させているが、スラグ層３３に対して斜めに移動させるようにしてもよい。この場合は、傾けた角度と、電極の移動距離とから、演算によりスラグ層の厚さを求めることができる。
【００４９】
上記の測定装置によれば、図１１からも分かるように、電極３５の電位の変化が、基準電位である０（Ｖ）と、この基準電位よりも高い高電位であるプラス電位と、この基準電位よりも低い低電位であるマイナス電位のいずれかへの変化であるので、これらの変化の検知を正確に行なうことができ、これらの検知を基にして、電極３５の移動距離を正確に求めることができることから、スラグ層３３の厚さを正確に知ることができる。
また、電極３５に接続されたコネクタなどの接触抵抗により、電極３５と容器３１との間のインピーダンスが変化しても、電極３５の電位の変化は、基準電位と、この基準電位よりも高い高電位と、この基準電位よりも低い低電位のいずれかへの変化であることに変わりはないので、上記の測定装置による測定方法は、電極３５と容器３１との間のインピーダンスの変化の影響を受けにくい測定方法といえる。
【００５０】
上記の第１実施例では、前述したように、溶鋼を対象としているが、上記で説明した内容は、一般的に溶融金属を対象とした場合にも適用できる。
【００５１】
溶鋼のスラグ層厚さを測定するスラグ層厚さ測定装置では、その電極の材質を、Mo、Co、Cr、Mnの中から、少なくとも一つを含む鉄の合金とすることが推奨される。上述したスラグ層厚さ測定装置では、容器内の溶湯が高温であり、この溶湯に浸漬した電極は、時間がたつと溶融してしまう。そこで、溶融するまでの時間をできるだけ長くすることが望ましいが、この点で、上記の合金は溶融しにくく、電極の材質として優れている。
【００５２】
上述したスラグ層厚さ測定装置において、スラグ層の厚さを測定する際、酸素濃度の測定に用いる電極を酸素プローブの溶鋼電極と併用して用いるようにしても良い。このようにすることにより、同時に、スラグ層の厚さの測定と、酸素濃度の測定を行なうことができると共に、電極を併用できるので、測定装置のコスト低減を図ることができる。
【００５３】
また、上述したスラグ層厚さ測定装置において、酸素プローブの溶鋼電極と併用する電極と、酸素プローブのジルコニア極との下部先端位置をそろえると共に、双方の先端部分以外の部分を石英管等の防護用パイプで覆って用いるようにしても良い。このようにすることにより、電極と、酸素プローブのジルコニア極の双方に対して、スラグが付着するのを防止でき、また、同時に、スラグ層の厚さの測定と、酸素濃度の測定を行なうことができると共に、電極を併用できるので、測定装置のコスト低減を図ることができる。
【００５４】
また、上述したスラグ層厚さ測定装置において、電極を溶鋼温度測定プローブへ取り付けて用いるようにしても良い。このようにすることにより、同時に、スラグ層の厚さの測定と、溶鋼温度の測定を行なうことができると共に、電極を併用できるので、測定装置のコスト低減を図ることができる。
【００５５】
前述したように、転炉等の溶鋼を収容した容器では、下部に浸漬管を備えた真空槽を溶鋼上に浮遊するスラグの上方に配設すると共に、浸漬管を溶鋼内に浸漬させ、真空槽内に溶鋼を取り込んで、Ｃａ等を加えて、溶鋼中のスラグ成分の粒子を凝集させることにより、溶鋼中のスラグ成分を取り除きやすくしている。この場合、浸漬管を水冷する必要があり、この冷却水と溶鋼とが触れると爆発を生じる恐れがあるので、真空槽のスラグ表面からの高さを一定にする位置制御が必要であり、このため、溶鋼層の表面レベル位置を測定する必要がある。そこで、次に、スラグ層厚さの測定と共に、溶鋼層の表面レベル位置、即ち、溶湯を収容した容器の開口部上方で、容器から予め定められた一定距離離れて位置する定点から溶鋼層の表面までの距離の測定を行なう、本発明の第２実施例である、スラグ層厚さ及び溶鋼層表面レベル位置測定装置について述べる。この装置で測定する、定点から溶鋼層の表面までの距離の変化を、定点と真空槽との位置関係に反映させることにより、真空槽の位置を制御することができる．
【００５６】
図１５は、本発明の第２実施例であるスラグ層厚さ及び溶鋼層表面レベル位置測定装置の構成を示した説明図である。図１５において、図８と同番号は、図８と同内容である。図８と異なるのは、下部に浸漬管２５を備えた真空槽２４を転炉３１の上方に配設し、電極３５が定点４９に位置する状態を検知するための、定点検知用マーク２８をランス３７の側面に設け、この定点検知用マーク２８を検出するための光源２７及びセンサ２９を設けると共に、定点検知回路４６を設け、センサ２９の出力をこの定点検知回路４６へ入力していると共に、この定点検知回路４６の出力をマイクロコンピュータ４７へ入力している点である。また、本第２実施例でも、第１実施例同様、溶鋼層３２からスラグ層３３を通って大気層３４まで上昇移動させて、スラグ層の厚さ、及び、定点から溶鋼層の表面までの距離を測定する。
【００５７】
この場合、スラグ層の厚さの測定方法は、第１実施例と全く同じである。また、定点から溶鋼層の表面までの距離は、電極３５が、溶鋼層３２からスラグ層３３に移行する時点、即ち、溶鋼−スラグ界面通過時点から、定点に至るまでに、電極３５、即ち、ランス３７の移動した距離を測定すればよい。溶鋼−スラグ界面通過時点は、電極３５の電位が、基準電位から前記高電位へ変化する時点であり、また、定点に至った時点は、センサ２９が定点検知用マーク２８を検知した時点であるから、これらの検知信号が、定点検知回路４６を介してマイクロコンピュータ４７へ入力されることにより、第１実施例と同様にして、マイクロコンピュータ４７により、スラグ層の厚さおよび定点から溶鋼層の表面までの距離が演算され、その状況が、ディスプレイ４８で表示される。
【００５８】
上記の第２実施例であるスラグ層厚さ及び溶鋼層表面レベル位置測定装置においても、第１実施例におけるのと同様に、電極を降下移動させて測定してもよい。また、電極３５の移動距離を、電極の移動速度と移動時間とから、演算により求めてもよい。そのために、電極の移動速度を、図６に示すような２個の電極を用いて測定するようにしてもよい。また、電極を、スラグ層に対して斜めに移動させるようにしてもよい。また、溶鋼を収容する容器として、取鍋を使用してもよい。また、溶鋼のみならず、一般の溶融金属を用いることもできる。
【００５９】
上記の第２実施例であるスラグ層厚さ及び溶鋼層表面レベル位置測定装置によれば、上述のスラグ層厚さ測定装置に使用される原理を用いることにより、スラグ層厚さの測定のみならず、スラグ層の表面レベル位置を測定することができる。
【００６０】
上述した第１実施例および第２実施例のいずれにおいても、直流電源１１は、電極３５側を陰極としているが、電極３５側を陽極としても、原理的には、測定可能である。即ち、図８および図１５において、Ｖccの極性を逆にしても、スラグ層が示す電気的特性が、その下層の溶鋼や上層の大気と異なることを利用したスラグ層厚さの測定や、スラグ層の表面レベル位置の測定を行なうことができる。
【００６１】
【発明の効果】
請求項１または請求項２記載のスラグ層厚さ測定方法によれば、電極と容器との間の電気的特性である電極−容器間特性の変化である、導電性、発電性、または、絶縁性の各性質相互間の変化を利用して測定を行なう。この変化は、インピーダンスの変化のような同質なもの相互間の変化ではなく、異質なもの相互間の変化であるので、変化を明瞭にとらえることができ、スラグ層の厚さを正確に測定することができるスラグ層厚さ測定方法を提供できる。
また、電極自身は、コスト的には高価ではないことから、測定の都度交換してよく、電極に損傷防止を施す必要がないため、これらのスラグ層厚さ測定方法によれば、コストの低いスラグ層厚さ測定方法を提供することができる。
【００６２】
請求項３または請求項４記載のスラグ層厚さ測定方法によれば、電極の電位の変化が、基準電位と、この基準電位よりも高い高電位と、この基準電位よりも低い低電位のいずれかへの変化であり、変化をデジタル的にとらえることができるので、変化の検知を正確に行なうことができ、これらの検知を基にして、電極の移動距離を正確に求めることができることから、スラグ層の厚さを正確に知ることができるスラグ層厚さ測定方法を提供できる。
また、電極からこの電位を測定する回路までの途中のコネクタなどの接触抵抗により、電極と容器との間のインピーダンスが変化しても、電極の電位の変化は、基準電位と、この基準電位よりも高い高電位と、この基準電位よりも低い低電位のいずれかへの変化であることに変わりはないので、この測定方法によれば、電極と容器との間のインピーダンスの変化の影響を受けにくいスラグ層厚さ測定方法を提供できる。
【００６３】
請求項５記載のスラグ層厚さ測定方法によれば、電極の移動距離を直接測定する必要がなく、測定方法が簡便になるスラグ層厚さ測定方法を提供できる。
【００６４】
請求項６記載のスラグ層厚さ測定装置によれば、電極の電位の変化が、基準電位と、この基準電位よりも高い高電位と、この基準電位よりも低い低電位のいずれかへの変化であり、変化をデジタル的にとらえることができるので、変化の検知を正確に行なうことができ、これらの検知を基にして、電極の移動距離を正確に求めることができることから、スラグ層の厚さを正確に知ることができるスラグ層厚さ測定装置を提供できる。
また、電極に接続されたコネクタなどの接触抵抗により、電極と容器との間のインピーダンスが変化しても、電極の電位の変化は、基準電位と、この基準電位よりも高い高電位と、この基準電位よりも低い低電位のいずれかへの変化であることに変わりはないので、この測定方法によれば、電極と容器との間のインピーダンスの変化の影響を受けにくいスラグ層厚さ測定装置を提供できる。
【００６５】
請求項７記載のスラグ層厚さ測定装置によれば、請求項６記載のスラグ層厚さ測定装置の効果に加えて、次の効果を有する。即ち、このスラグ層厚さ測定装置によれば、電極の移動距離を直接測定する必要がなく、従って、測定方法が簡便になるスラグ層厚さ測定装置を提供できる。
【００６６】
請求項８記載のスラグ層厚さ測定装置によれば、電極の移動速度を予め定めておく必要がないスラグ層厚さ測定装置を提供できる。
【００６７】
請求項９記載のスラグ層厚さ測定装置によれば、溶鋼用のスラグ層厚さ測定装置を提供できる。
【００６８】
請求項１０記載のスラグ層厚さ測定装置によれば、スラグ層厚さの測定の際、電極溶融しにくいスラグ層厚さ測定装置を提供することができる。
【００６９】
請求項１１記載のスラグ層厚さ測定装置によれば、同時に、スラグ層の厚さの測定と、酸素濃度の測定を行なうことができると共に、電極を併用できるので、測定装置のコスト低減を図ることができる。
【００７０】
請求項１２記載のスラグ層厚さ測定装置によれば、電極と、酸素プローブのジルコニア極の双方に対して、スラグが付着するのを防止でき、また、同時に、スラグ層の厚さの測定と、酸素濃度の測定を行なうことができると共に、電極を併用できるので、測定装置のコスト低減を図ることができる。
【００７１】
請求項１３記載のスラグ層厚さ測定装置によれば、同時に、スラグ層の厚さの測定と、溶鋼温度の測定を行なうことができると共に、電極を併用できるので、測定装置のコスト低減を図ることができる。
【００７２】
請求項１４から請求項１８に記載のスラグ層厚さ及び溶融金属層表面レベル位置測定方法、あるいは、請求項１９及び請求項２０に記載のスラグ層厚さ及び溶融金属層表面レベル位置測定装置によれば、上述のスラグ層厚さ測定方法またはスラグ層厚さ測定装置に使用される原理を用いることにより、スラグ層厚さの測定のみならず、溶融金属層の表面レベル位置を測定することができる。
【図面の簡単な説明】
【図１】本発明の第１のスラグ層厚さ測定方法の原理を示した説明図
【図２】本発明の第３のスラグ層厚さ測定方法の原理を示した説明図
【図３】図２の等価回路図
【図４】図３の等価回路図で、（ａ）は電極が溶融金属層に位置している場合、（ｂ）は電極がスラグ層に位置している場合、（ｃ）は電極が大気層に位置している場合を示す。
【図５】電極を、溶融金属層からスラグ層を通って大気層まで上昇移動させた場合の、容器の電位を基準電位とした電極の電位の変化を示した図
【図６】２個の電極を用いて電極の移動速度を測定する方法の説明図で、（ａ）はその原理、（ｂ）は各電極の電位の変化を示す。
【図７】本発明の第１のスラグ層厚さ及び溶融金属層表面レベル位置測定方法の原理を示した説明図
【図８】本発明の第１実施例であるスラグ層厚さ測定装置の構成を示した説明図
【図９】図８における、電極、プローブ、及びランスの接合部分の構造を示した説明図
【図１０】第１実施例の電極の移動時間と移動速度からその移動距離を求める方法を用いたスラグ層厚さ測定装置のディスプレイの表示例
【図１１】（ａ）、（ｂ）、（ｃ）、（ｄ）共に、第１実施例の電極の移動時間と移動速度からその移動距離を求める方法を用いたスラグ層厚さ測定装置における電極の電位の変化の表示例
【図１２】送りねじ機構を採用したプローブの断面図
【図１３】酸素濃度測定装置と併用したスラグ層厚さ測定装置の構成図（１）
【図１４】酸素濃度測定装置と併用したスラグ層厚さ測定装置の構成図（２）
【図１５】本発明の第２実施例であるスラグ層厚さ及び溶鋼層表面レベル位置測定装置の構成を示した説明図
【符号の説明】
１容器
２溶融金属層
３スラグ層
４大気層
５電極
６スラグ層厚さ
７溶融金属−スラグ界面通過時点
８スラグ−大気界面通過時点
９定点
１０定点から溶融金属層の表面までの距離
１１直流電源Ｖcc
１２抵抗Ｒｘ
１３電位測定手段
１９切換スイッチ
２１電極
２２電極
２３測定装置
２５真空槽
２６浸漬管
２７光源
２８定点検知用マーク
２９センサ
３１転炉
３２溶鋼層
３３スラグ層
３４大気層
３５電極
３６プローブ
３７ランス
３８ランス移動装置
３９エンコーダ
４０ａ、４０ｂ計測装置
４１直流電源Ｖcc
４２抵抗Ｒｘ
４３電極電位測定回路(アナログ回路)
４４ランス移動制御回路
４５エンコーダパルスカウント回路
４６定点検知回路
４７マイクロコンピュータ
４８ディスプレイ
４９定点
５１接触コンタクト
５２リング接触子
６１ランス（プローブ）
６２ライフル溝具内径部
６３ランス保持部
６４ランス保持部取り付け台
６５電極
７１ジルコニア電極
７２溶鋼電極
７３酸素プローブ
７４酸素濃度測定器
７５スラグ層厚さ測定器
７６石英管[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for measuring a slag layer thickness or a slag layer thickness and a surface level position of a molten metal layer, and a measuring apparatus thereof.
[0002]
[Prior art]
In converters used for refining steel from pig iron produced in a blast furnace, it is necessary to measure the thickness of a slag layer floating on the surface of the molten steel in order to control refining. For this reason, using one or two electrodes, the method of obtaining the thickness of the slag layer by measuring the difference in impedance of the molten steel, slag, and atmosphere, or the induced voltage of the electromagnetic coil is the molten steel, slag, and A method for determining the thickness of the slag layer by utilizing the difference in the atmosphere is used.
[0003]
[Problems to be solved by the invention]
However, the measurement method using the difference in impedance cannot ignore the connection impedance in the connector of the lance that holds the electrode, and the error is large, and the method using the electromagnetic coil is the method when the electromagnetic coil is immersed in molten steel. It was necessary to prevent damage, and the apparatus became large and expensive, each of which was a problem.
The present invention has been made to solve such problems, and an object of the present invention is to provide a method and apparatus for measuring a slag layer thickness with low error and low cost.
[0004]
[Means for Solving the Problems]
Molten steel filled in a vessel such as a converter is mainly composed of molten metal, and its electrical properties show conductivity as metal, whereas the slag layer floating on the surface of molten steel is It is an electrolyte, and it has been found that the characteristics as a battery are exhibited when an electrode is immersed in the electrolyte. Moreover, the air which occupies the upper layer of a slag layer has insulation as an electrical property so that it may be known well. The present invention has been made paying attention to these points, and measures the thickness of the slag layer by utilizing the fact that the electrical characteristics of the slag layer are different from the molten steel of the lower layer and the atmosphere of the upper layer. It is something to try. The electrical characteristics exhibited by the slag layer are not limited to molten steel, but can be applied to molten metal in general, and the present invention is directed to molten metal.
[0005]
Specifically, the first slag layer thickness measuring method of the present invention is the following method.
That is, a method of measuring the thickness of the slag layer of the molten metal in which the slag layer floats on the surface of the molten metal layer,
The electrode is moved upwardly from the molten metal layer through the slag layer to the atmospheric layer occupying the upper layer of the slag layer, and the electrical characteristics between the container containing the molten metal and the electrode having conductivity To monitor the electrode-container characteristics,
The electrode-container characteristic is that the electrode moves to the slag layer and functions as an electrolyte from the conductivity due to the presence of the molten metal layer when the electrode is immersed in the molten metal layer. When the molten metal-slag interface passes, which is the time of transition to power generation by the inclusion of,
Detecting when the electrode escapes from the slag layer to the atmospheric layer, and the electrode-container characteristic passes through the slag-atmosphere interface, which is the time when the power generation property shifts to the insulating property due to the presence of the atmospheric layer. And
It is the slag layer thickness measuring method which measures the moving distance which the said electrode moved from the said molten metal-slag interface passage time to the said slag-atmosphere interface passage time, and becomes thickness of the said slag layer.
[0006]
FIG. 1 is an explanatory view showing the principle of the first slag layer thickness measuring method. In FIG. 1, 1 is a container, 2 is a molten metal layer, 3 is a slag layer, 4 is an atmospheric layer, and 5 is an electrode. The slag layer 3 is an electrolyte as described above, and exhibits characteristics as a chemical battery when an electrode is immersed therein. This is because an electromotive force is generated when cations (Si2 +, P2 +, etc.) and anions (O2-) in the molten slag exchange electrons through the electrodes.
[0007]
In this first slag layer thickness measurement method, the electrode 5 is moved up from the molten metal layer 2 through the slag layer 3 to the atmosphere layer 4, and the electrical characteristics between the electrode 5 and the container 1 during this period are as follows. The thickness of the slag layer 3 is measured using a change in characteristics between a certain electrode and the container, and FIG. 1 is an explanatory diagram of this measuring method. A container 1 such as a converter for containing molten metal is generally formed by stacking refractory bricks inside a metal container, and the container 1 alone does not have conductivity, but the molten metal is contained in the container 1. By accommodating, metal adheres to the inner surface of the container 1, so that the space between the inner surface of the container 1 and the ground has conductivity. That is, the container becomes conductive. Therefore, by examining the electrical characteristics between the electrode 5 and the ground, the electrode-container characteristics, which are the electrical characteristics between the electrode 5 and the container 1, can be examined.
In this case, in FIG. 1, when the electrode 5 is located on the molten metal layer 2 (a), since the molten metal layer 2 is in a molten state, the electrode-container characteristic is conductive. When the electrode 5 moves to the slag layer 3 (b), the electrode-container characteristic becomes power generation as described above. When the electrode 5 passes through the slag layer 3 and moves to the atmosphere layer 4 (c), the atmosphere is interposed and the electrode-container characteristics become insulating. Therefore, when the electrode 5 is moved upward from the molten metal layer 2 to the atmospheric layer 4, the electrode 5 passes through the boundary surface between the molten metal layer 2 and the slag layer 3 in which the electrode-container characteristic changes from conductivity to power generation. Detects a molten metal-slag interface passage time 7 and a slag-atmosphere interface passage time 8 at which the electrode 5 passes through the interface between the slag layer 3 and the atmospheric layer 4 where the electrode-container characteristic changes from power generation to insulation. During this time, the thickness of the slag layer 3 can be known by measuring the distance that the electrode 5 has moved upward.
[0008]
In the first slag layer thickness measuring method, the electrode 5 is moved up, but the electrode may be moved down. In this case, the second slag layer thickness measuring method is:
A method of measuring the thickness of the slag layer of the molten metal in which the slag layer floats on the surface of the molten metal layer,
The electrode is moved downward from the atmospheric layer occupying the upper layer of the slag layer to the molten metal layer through the slag layer, and the electrical characteristics between the conductive container containing the molten metal and the electrode To monitor the electrode-container characteristics,
This electrode-container characteristic shifts from insulation due to the presence of air when the electrode is in the air layer to power generation due to the interposition of the slag layer where the electrode is immersed in the slag layer and functions as an electrolyte. When the air-slag interface is passed, the electrode moves from the slag layer to the molten metal layer, and the electrode-container characteristic is changed from the power generation property to the conductivity due to the intervention of the molten metal layer. Detecting the slag-molten metal interface passage time that is the time of transition,
It is the slag layer thickness measuring method which measures the moving distance which the said electrode moved from the said air-slag interface passage time to the said slag-molten metal interface passage time, and becomes the thickness of the said slag layer.
[0009]
In the case of this second slag layer thickness measuring method, the electrode is moved down from the atmospheric layer through the slag layer to the molten metal layer, and the atmospheric layer and slag in which the electrode-container characteristics change from insulating to power generating properties. Slag-molten metal interface where the electrode passes through the interface between the slag layer and the molten metal layer where the electrode-container characteristics change from power generation to conductivity By detecting the time of passage and measuring the distance that the electrode has moved downward during this time, the thickness of the slag layer can be known as in the case of moving the electrode upward.
[0010]
According to said 1st slag layer thickness measuring method or 2nd slag layer thickness measuring method, it is the electrical conductivity which is a change of the electrode-container characteristic which is an electrical property between an electrode and a container. The measurement is performed by utilizing the change between the properties such as the property, the power generation property, or the insulation property. This change is not between homogeneous things like impedance changes, but between heterogeneous ones, so you can capture the change clearly and accurately measure the thickness of the slag layer be able to.
In addition, since the electrode itself is not expensive in cost, it may be replaced every time measurement is performed, and it is not necessary to prevent damage to the electrode. Therefore, according to these slag layer thickness measurement methods, the cost is low. A method for measuring the slag layer thickness can be provided.
[0011]
In the first slag layer thickness measuring method and the second slag layer thickness measuring method, the molten metal-slag interface passage time, the slag-atmosphere interface passage time, the atmosphere-slag interface passage time, or the slag -A slag layer thickness measurement method may be considered in which the detection of the passage time of the molten metal interface is performed by measuring the potential of the electrode with respect to the container.
First, the third slag layer thickness measuring method according to this method is the above-described first slag layer thickness measuring method,
A DC power source Vcc having the electrode side as a cathode and a resistor Rx connected in series with the power source are inserted between the electrode and the container, and the values of the DC power source Vcc and the resistor Rx are set to the electrode. When the electrode is immersed in the slag layer, the potential of the electrode with the potential of the container as a reference potential is set to be a high potential higher than the reference potential,
Moving the electrode from the molten metal layer to the atmospheric layer, measuring the potential of the electrode relative to the reference potential;
As the time when the molten metal-slag interface passes, the time when the potential of the electrode changes from the reference potential to the high potential,
In addition, as the time of passage through the slag-atmosphere interface, the time when the potential of the electrode changes from the high potential to a low potential lower than the reference potential,
It is a slag layer thickness measuring method formed by detection.
[0012]
FIG. 2 is an explanatory view showing the configuration of a measuring apparatus used in the third slag layer thickness measuring method. In FIG. 2, a DC power source Vcc 11 having the electrode 5 side as a cathode and a resistor Rx 12 connected in series with the power source 11 are inserted between the electrode 5 and the container 1 of FIG. That is, potential measuring means 13 for measuring the voltage between the electrode 5 and the container 1 is provided. Here, the values of the DC power supply 11 and the resistor Rx12 are set so that the potential of the electrode 5 with the potential of the container 1 as the reference potential is higher than the reference potential when the electrode is immersed in the slag layer. Is set.
[0013]
FIG. 3 shows the equivalent circuit of FIG. In FIG. 2, the movement of the electrode 5 between the molten metal layer 2, the slag layer 3, or the atmospheric layer 4 is electrically the same as switching the changeover switch 19 of FIG. 3. That is, when the electrode 5 is positioned on the molten metal layer 2 (a), since the molten metal layer 2 is in a molten state of the metal, the electrode-container characteristic is conductive. The container 1 is short-circuited via the molten metal layer 2. When the electrode 5 is positioned on the slag layer 3 (b), the battery characteristics are shown because the slag layer 3 is an electrolyte, and the electrode 5 is placed between the electrode 5 and the container 1 instead of the slag layer 3. This is the same as connecting a battery with electric power Eo and internal resistance Ro. When the electrode 5 is located in the atmosphere layer 4 (c), the atmosphere has an insulating property, so that the space between the electrode 5 and the container 1 is opened via the atmosphere layer 4. An equivalent circuit in each of these cases is shown in FIGS.
That is, in FIG. 2, when the potential of the container 1 is set to the reference potential 0 (V), the electrode 5 is positioned on the molten metal layer 2 (a), the electrode 5 is positioned on the slag layer 3 (b), or When the potential of the electrode 5 with respect to each reference potential is Va, Vb, and Vc when they are located in the atmospheric layer 4 (c), these are shown in (a) to (c) of FIG. Thus, Va = 0 (V) (reference potential), Vb = (EoRx−VccRo) / (Ro + Rx) (V), and Vc = −Vcc (V) (low potential lower than the reference potential). Here, Vb in FIG. 4B is a high potential higher than the reference potential with respect to the potential of the container 1, which is the reference potential, by setting the values of the DC power supply Vcc and the resistance Rx. It becomes a positive potential with respect to the ground of 4 (b). In general, Rx is on the order of several hundred kiloohms, and the internal resistance Ro in the battery characteristics indicated by the slag layer 3 is on the order of tens to hundreds of ohms. Therefore, as shown in FIG. 4B, Vb is substantially equal to Eo. Become. Since this electromotive force is anodic with respect to the ground, Vb becomes a positive potential.
[0014]
Using the measurement circuit described above, when the electrode 5 is moved up from the molten metal layer 2 through the slag layer 3 to the atmosphere layer 4, the potential of the electrode 5 with the potential of the container 1 as a reference potential is measured. As shown in FIG. When the measurement is started at the time Ta and the electrode 5 is positioned on the molten metal layer 2, Va is 0 (V). At the time Tb when the electrode 5 moves from the molten metal layer 2 to the slag layer 3, that is, at the time when the electrode 5 passes through the molten metal-slag interface, Vb becomes a positive potential. Furthermore, at the time Tc when the contact 5 moves from the slag layer 3 to the atmosphere layer 4, that is, when the contact 5 passes through the slag-atmosphere interface, Vc becomes −Vcc (V), which is a negative potential.
Then, if the time when the potential of the electrode 5 changes from 0 (V) to a positive potential, that is, the time when the potential changes from the reference potential to a higher potential higher than the reference potential, the time when the molten metal-slag interface passes is detected. Therefore, if the time point when the potential of the electrode 5 changes from a positive potential to a negative potential, that is, when the potential changes from a high potential higher than the reference potential to a low potential lower than the reference potential, the slag-atmosphere interface is detected. This means that the passage time has been detected.
Therefore, based on these detections, the thickness of the slag layer 3 can be known by determining the moving distance that the electrode 5 has moved from when the molten metal-slag interface passes to when it passes through the slag-atmosphere interface.
[0015]
In the third slag layer thickness measuring method, the electrode is moved up, but the case where the electrode is moved down can also be measured by the same principle. The fourth slag layer thickness measuring method in this case is the above-described second slag layer thickness measuring method,
A DC power source Vcc having the electrode side as a cathode and a resistor Rx connected in series with the power source are inserted between the electrode and the container, and the values of the DC power source Vcc and the resistor Rx are set to the electrode. When the electrode is immersed in the slag layer, the potential of the electrode with the potential of the container as a reference potential is set to be a high potential higher than the reference potential,
Moving the electrode down from the atmospheric layer to the molten metal layer, measuring the potential of the electrode relative to the reference potential;
As the time of passage through the air-slag interface, the time when the potential of the electrode changes from a low potential lower than the reference potential to the high potential,
In addition, as the time of passing through the slag-molten metal interface, the time when the potential of the electrode changes from the high potential to the reference potential,
It is a slag layer thickness measuring method formed by detection.
[0016]
According to the third slag layer thickness measuring method or the fourth slag layer thickness measuring method, the change in the potential of the electrode is a reference potential, a high potential higher than the reference potential, and the reference It is a change to one of the low potentials lower than the potential, and since the change can be digitally detected, the change can be detected accurately, and based on these detections, the movement distance of the electrode can be determined. Since it can be calculated | required correctly, the thickness of a slag layer can be known correctly.
In addition, even if the impedance between the electrode and the container changes due to the contact resistance of the connector or the like connected to the electrode, the change in the electrode potential is caused by the reference potential, a higher potential higher than the reference potential, Since it is still a change to any one of low potentials lower than the reference potential, the measurement method described above can be said to be a method that is not easily affected by the impedance change between the electrode and the container.
[0017]
In the first, second, third, or fourth slag layer thickness measuring method, the moving distance of the electrode is directly measured, but the moving speed of the electrode is constant and the air-slag interface is passed. Measuring the moving time of the electrode from the time point to the time of passing through the slag-molten metal interface or from the time of passing through the molten metal-slag interface to the time of passing through the slag-atmosphere interface, and the moving time and the moving speed of the electrode Therefore, the movement distance of the electrode may be obtained by calculation.
That is, as the fifth slag layer thickness measuring method, in the first, second, third, or fourth slag layer thickness measuring method,
While making the moving speed of the upward movement or the downward movement of the electrode constant,
When using a method of moving the electrode upward from the molten metal layer to the atmospheric layer, measure the movement time of the electrode from the molten metal-slag interface passage time to the slag-atmosphere interface passage time,
When using the method of moving the electrode down from the atmosphere layer to the molten metal layer, measuring the movement time of the electrode from the time of passing the atmosphere-slag interface to the time of passing the slag-molten metal interface,
Instead of measuring the travel distance of the electrode,
There is a slag layer thickness measuring method in which the moving distance of the electrode is obtained by calculation from the moving speed and the moving time of the electrode.
[0018]
According to this method, it is not necessary to directly measure the moving distance of the electrode, and the measurement method becomes simple.
[0019]
Next, the slag layer thickness measuring apparatus of the present invention will be described. First, the first slag layer thickness measuring device is:
Electrodes,
An electrically conductive container containing a molten metal in which a slag layer floats on the surface of the molten metal layer, and the electrode is moved up and moved from the molten metal layer through the slag layer to the atmospheric layer occupying the upper layer of the slag layer. Or an electrode moving means for moving down from the atmospheric layer through the slag layer to the molten metal layer,
A DC power source Vcc having the electrode side as a cathode and a resistor Rx connected in series with the power source are inserted between the electrode and the container, and the values of the DC power source Vcc and the resistor Rx are determined by the electrode. A measurement circuit formed by setting the potential of the electrode to be a potential higher than the reference potential, using the potential of the container as a reference potential when immersed in the slag layer;
A potential measuring means for measuring the potential of the electrode with respect to the reference potential;
From the time point when the potential measuring means detects the change from the reference potential to the high potential to the time point when the high potential changes to a lower potential lower than the reference potential, or from the low potential to the high potential. An electrode movement distance measuring means for measuring a movement distance of the electrode from the time of change to the time of change from the high potential to the reference potential;
It is the slag layer thickness measuring apparatus comprised by these.
[0020]
In the first slag layer thickness measuring apparatus, in the case where the electrode is moved up from the molten metal layer to the atmospheric layer that occupies the upper layer of the slag layer, the potential measuring means includes a container and an electrode that contain the molten metal. As the electrode-container characteristic between and when the molten metal-slag interface transitions from conductivity to power generation, the electrode potential changes from the reference potential to a higher potential than the reference potential. Detecting the time when the potential of the electrode changes from a high potential to a low potential lower than the reference potential, as the time of passage through the slag-atmosphere interface from power generation to insulation. And an electrode movement distance measurement means calculates | requires the movement distance of the electrode from a molten metal-slag interface passage time to a slag-atmosphere interface passage time, and makes it the thickness of a slag layer.
When the electrode is moved down from the atmospheric layer through the slag layer to the molten metal layer, the potential measuring means shows that the electrode-to-container characteristic between the electrode containing the molten metal and the electrode is the atmospheric layer. When the electrode passes through the air-slag interface where it is immersed in the slag layer that functions as an electrolyte and shifts to power generation, the electric potential of the electrode changes from a low potential lower than the reference potential to the reference potential. While detecting the point of time when the potential changes to a high potential, the electrode-container characteristic is determined as the point of time when the electrode potential passes through the slag-molten metal interface when the electrode enters the molten metal layer and shifts to conductivity from power generation. The time point when the potential changes from the high potential to the reference potential is detected. Then, the electrode moving distance measuring means obtains the moving distance of the electrode from the time when it passes through the atmosphere-slag interface to the time when it passes through the slag-molten metal interface, and this is the thickness of the slag layer.
[0021]
That is, this device is a device for determining the thickness of the slag layer based on the above-described third slag layer thickness measuring method or the fourth slag layer thickness measuring method, and its operation and effect are as follows. Since it is the same as the above-mentioned 3rd slag layer thickness measuring method or the 4th slag layer thickness measuring method, description is abbreviate | omitted.
[0022]
In the first slag layer thickness measuring apparatus, the electrode moving distance is obtained by the electrode moving distance measuring means that directly measures, but the second slag obtained by calculation from the moving speed and moving time of the electrode. A layer thickness measuring device is also conceivable. This second slag layer thickness measuring device is:
Electrodes,
A container having conductivity and containing molten metal with a slag layer floating on the surface of the molten metal layer;
The electrode is moved up from the molten metal layer through the slag layer to the atmospheric layer occupying the upper layer of the slag layer, or the molten metal passes from the atmospheric layer through the slag layer, with a constant moving speed. An electrode moving means for moving down to the layer;
A DC power source Vcc having the electrode side as a cathode and a resistor Rx connected in series with the power source are inserted between the electrode and the container, and the values of the DC power source Vcc and the resistor Rx are set to the electrode. A measurement circuit formed by setting the potential of the container to be a potential higher than the reference potential, using the potential of the container as a reference potential when the slag layer is immersed in the slag layer,
A potential measuring means for measuring the potential of the electrode with respect to the reference potential;
From the time point when the potential measuring means detects the change from the reference potential to the high potential to the time point when the high potential changes to a lower potential lower than the reference potential, or from the low potential to the high potential. An electrode movement time measuring means for measuring the movement time of the electrode from the time of change to the time of change from the high potential to the reference potential;
An electrode moving distance calculating means for calculating a moving distance of the electrode by calculation from the moving speed and the moving time of the electrode;
It is the slag layer thickness measuring apparatus comprised by these.
[0023]
This second slag layer thickness measuring device has the same effect as the fifth slag layer thickness measuring method because the moving distance of the electrode is obtained by calculation from the moving speed and moving time of the electrode. Further, except that the moving distance of the electrode is calculated from the moving speed and moving time of the electrode by calculation, it has the same configuration as the first slag layer thickness measuring apparatus, and its operation and effect are also described above. This is exactly the same as the first slag layer thickness measuring apparatus.
[0024]
In the second slag layer thickness measuring apparatus, a third slag layer thickness measuring apparatus that measures the moving speed of the electrode using two electrodes is conceivable. This third slag layer thickness measuring device is the above-described second slag layer thickness measuring device,
In addition to the electrodes, one electrode is added, and the lower ends of these two electrodes are provided at a certain distance in the moving direction, and
By moving these two electrodes simultaneously, the time shift of the potential detected by each of the two electrodes with respect to the container is measured, and the movement speed is determined from the time shift and the constant distance. It is a slag layer thickness measuring apparatus provided with a speed detection means.
[0025]
FIG. 6A is an explanatory diagram of the speed detection principle of the moving speed detection means used in the third slag layer thickness measuring apparatus. In FIG. 6A, the lower end of the electrode 22 is provided apart from the lower end of the electrode 21 by a distance D in the upward direction, which is the moving direction. And a second input. In addition, as a method for measuring the potentials of the electrodes 21 and 22 with respect to the container 1 in the measuring apparatus 23, the same method as the above-described electrode potential measuring method is used. Therefore, when the two electrodes 21 and 22 are simultaneously moved upward from the molten metal layer 2 through the slag layer 3 to the atmosphere layer 4, the potentials of the electrodes 21 and 22 are changed as shown in FIG. The input and the second input are shifted by T. Then, the upward moving speed S of the electrodes 21 and 22 is obtained by S = D / T.
According to this slag layer thickness measuring apparatus, it is not necessary to determine the moving speed of the electrode in advance.
[0026]
The first to third slag layer thickness measuring devices to the third slag layer thickness measuring device described above are intended for molten metal, but molten steel can be used as the molten metal.
[0027]
In slag layer thickness measurement equipment using molten steel as the molten metal, it is recommended that the electrode material used for this is an iron alloy containing at least one of Mo, Co, Cr, and Mn. The In the slag layer thickness measuring apparatus described above, the molten metal in the container is at a high temperature, and the electrode immersed in the molten metal melts over time. Therefore, it is desirable to make the time until melting as long as possible. However, in this respect, the above alloy is difficult to melt and is excellent as an electrode material.
[0028]
In each of the slag layer thickness measuring devices described above, when measuring the slag layer thickness, when the oxygen concentration needs to be measured, the electrode may be used in combination with the molten steel electrode of the oxygen probe. By doing so, the thickness of the slag layer and the oxygen concentration can be measured at the same time, and the electrodes can be used together, so that the cost of the measuring device can be reduced.
[0029]
In the above slag layer thickness measuring device, the lower tip positions of the electrode used in combination with the molten steel electrode of the oxygen probe and the zirconia electrode of the oxygen probe are aligned, and the portions other than both tip portions are protected with a quartz tube or the like. It may be used by covering with a pipe. By doing so, it is possible to prevent the slag from adhering to both the electrode and the zirconia electrode of the oxygen probe, and simultaneously measure the thickness of the slag layer and the oxygen concentration. In addition, since the electrodes can be used in combination, the cost of the measuring apparatus can be reduced.
[0030]
Moreover, in each slag layer thickness measuring apparatus mentioned above, you may make it use an electrode attached to a molten steel temperature measurement probe. By doing in this way, since the measurement of the thickness of a slag layer and the measurement of molten steel temperature can be performed simultaneously and an electrode can be used together, the cost of the measuring device can be reduced.
[0031]
By the way, in a container containing molten metal, such as a converter, a vacuum tank provided with a dip tube at the bottom is disposed above the slag floating on the molten metal, and the dip tube is immersed in the molten metal and vacuumed. The molten metal is taken into the tank and Ca or the like is added to agglomerate particles of the slag component in the molten metal, thereby making it easier to remove the slag component in the molten metal. In this case, it is necessary to cool the dip tube with water, and if this cooling water and the molten metal come into contact with each other, there is a risk of explosion, so it is necessary to control the position of the height from the surface of the molten metal layer in the vacuum chamber. Therefore, it is necessary to measure the surface level position of the molten metal layer.
The above description relates to a slag layer thickness measuring method or apparatus, but the principle used for this is not only the measurement of the slag layer thickness but also the measurement of the surface level position of the molten metal layer. Next, along with the measurement of the slag layer thickness, the surface level position of the molten metal layer, i.e. above the opening of the container containing the molten metal, a predetermined distance away from the container. A method for measuring the distance from the fixed point to the surface of the molten metal layer will be described.
[0032]
In this method, the first slag layer thickness and the molten metal layer surface level position measuring method are:
From the fixed point located at a predetermined distance from the container to the surface of the molten metal layer above the opening of the container that is electrically conductive and contains molten metal in which the slag layer floats on the surface of the molten metal layer A method for measuring distance and thickness of the slag layer,
The electrode is moved between the molten metal layer through the slag layer to the fixed point in the atmospheric layer that occupies the upper layer of the slag layer, and the electrode-container is an electrical property between the container and the electrode. Monitor the characteristics,
The electrode-container characteristic is that the electrode moves to the slag layer and functions as an electrolyte from the conductivity due to the presence of the molten metal layer when the electrode is immersed in the molten metal layer. When the molten metal-slag interface passes, which is the time of transition to power generation by the inclusion of,
When the electrode escapes from the slag layer to the atmospheric layer, and the electrode-container characteristic transitions from the power generation property to the insulating property due to the presence of the atmospheric layer, the slag-atmosphere interface passing time point. As well as
From the time when the molten metal-slag interface passes to the time when the electrode passes the slag-atmosphere interface, the distance traveled by the electrode is measured to obtain the thickness of the slag layer. This is a method for measuring the slag layer thickness and the molten metal layer surface level position, which is the distance from the fixed point to the surface of the molten metal layer by measuring the distance traveled by the electrode up to a fixed point.
[0033]
FIG. 7 is an explanatory diagram showing the measurement principle of the above method. In the above method, in FIG. 7, a position that is a predetermined distance away from the container 1 is provided above the opening of the container 1 that is conductive and accommodates the molten metal in which the slag layer floats on the surface of the molten metal layer. The electrode 5 is moved upward from the molten metal layer through the slag layer to the fixed point 9 in the atmospheric layer that occupies the upper layer of the slag layer, and the electric power between the electrode 5 and the container 1 in the meantime. The thickness 6 of the slag layer and the distance 10 from the fixed point 9 to the surface of the molten metal layer 2 are measured using the change in the electrode-container characteristic, which is a typical characteristic. In the above method, the method of measuring the thickness 6 of the slag layer is exactly the same as the first method of measuring the thickness of the slag layer. Moreover, the detection method of the molten metal-slag interface passage time point 7 used for measuring the distance 10 from the fixed point 9 to the surface of the molten metal layer 2 is exactly the same as the first slag layer thickness measuring method. -The distance 10 from the fixed point 9 to the surface of the molten metal layer 2 can be determined by measuring the distance that the electrode 5 has moved from the slag interface passage time point 7 to the fixed point 9.
[0034]
In the above method, the electrode 5 is moved up, but the electrode may be moved down. In addition, as described above, in FIG. 7, the measurement of the surface level position of the molten metal layer is to measure the distance 10 from the fixed point 9 to the surface of the molten metal layer 2. Here, the distance from the fixed point to the surface of the molten metal layer is determined from the time when the molten metal-slag interface passes to the fixed point, or from the fixed point to the time when the molten metal layer passes through the slag-molten metal interface. The detection method used in each of the slag layer thickness measurement methods described above can be performed by measuring the distance or time of movement, and the detection of the molten metal-slag interface passage time or the slag-molten metal interface passage time is performed. Can be used as is. Therefore, the second, third, fourth, or fifth slag layer thickness and molten metal layer surface level position measuring method, or the first or second slag layer thickness and molten metal layer surface level position measurement. By applying each of the above-described slag layer thickness measuring methods or each of the above-described slag layer thickness measuring devices as an apparatus, the following methods and apparatuses can be considered.
[0035]
The second slag layer thickness and the molten metal layer surface level position measuring method are:
From the fixed point located at a predetermined distance from the container to the surface of the molten metal layer above the opening of the container that is electrically conductive and contains molten metal in which the slag layer floats on the surface of the molten metal layer A method for measuring distance and thickness of the slag layer,
An electrode that moves downward from the fixed point in the atmospheric layer that occupies the upper layer of the slag layer, passes through the slag layer to the molten metal layer, accommodates the molten metal, and the electrode; The electrode-container characteristics, which are electrical characteristics between
This electrode-container characteristic shifts from insulation due to the presence of air when the electrode is in the air layer to power generation due to the interposition of the slag layer where the electrode is immersed in the slag layer and functions as an electrolyte. Passing through the air-slag interface,
Passing through the slag-molten metal interface when the electrode moves from the slag layer to the molten metal layer and the electrode-container characteristics shift from the power generation property to the conductivity due to the intervention of the molten metal layer Detecting the time and
From the fixed point to the point of passage through the slag-molten metal interface, the distance traveled by the electrode is measured, and the distance from the fixed point to the surface of the molten metal layer,
The slag layer thickness and the surface level position of the molten metal layer are measured by measuring the distance traveled by the electrode from the air-slag interface passing time to the slag-molten metal interface passing time. This is a measurement method.
[0036]
The third slag layer thickness and molten metal layer surface level position measuring method is the first slag layer thickness and molten metal layer surface level position measuring method,
A DC power source Vcc having the electrode side as a cathode and a resistor Rx connected in series with the power source are inserted between the electrode and the container, and the values of the DC power source Vcc and the resistor Rx are When the electrode is immersed in the slag layer, the potential of the electrode with the potential of the container as a reference potential is set to be a high potential higher than the reference potential,
Moving the electrode from the molten metal layer to the atmospheric layer, measuring the potential of the electrode relative to the reference potential;
As the time when the molten metal-slag interface passes, the time when the potential of the electrode changes from the reference potential to the high potential,
In addition, as the time when the slag-atmosphere interface passes, the time when the potential of the electrode changes from the high potential to a low potential lower than the reference potential,
This is a method for measuring the thickness of the slag layer and the surface level position of the molten metal layer.
[0037]
The fourth slag layer thickness and molten metal layer surface level position measuring method is the second slag layer thickness and molten metal layer surface level position measuring method,
A DC power source Vcc having the electrode side as a cathode and a resistor Rx connected in series with the power source are inserted between the electrode and the container, and the values of the DC power source Vcc and the resistor Rx are When the electrode is immersed in the slag layer, the potential of the electrode with the potential of the container as a reference potential is set to be a high potential higher than the reference potential,
Moving the electrode down from the atmospheric layer to the molten metal layer, measuring the potential of the electrode relative to the reference potential;
The time when the potential of the electrode changes from a low potential lower than the reference potential to the high potential as the air-slag interface passage time,
In addition, as the time of passage through the slag-molten metal interface, the time when the potential of the electrode changes from the high potential to the reference potential,
This is a method for measuring the thickness of the slag layer and the surface level position of the molten metal layer.
[0038]
The fifth slag layer thickness and molten metal layer surface level position measuring method is the first, second, third, or fourth slag layer thickness and molten metal layer surface level position measuring method,
While making the moving speed of the upward movement or the downward movement of the electrode constant,
When using the method of moving up the electrode from the molten metal layer to the atmospheric layer,
For calculating the thickness of the slag layer, measure the movement time of the electrode from the molten metal-slag interface passage time to the slag-atmosphere interface passage time,
For the calculation of the distance from the fixed point to the surface of the molten metal layer, measure the movement time of the electrode from the molten metal-slag interface passing time to the fixed point,
When using a method of moving down the electrode from the atmospheric layer to the molten metal layer,
For calculating the distance from the fixed point to the surface of the molten metal layer, measure the movement time of the electrode from the fixed point to the slag-molten metal interface passing time,
For the thickness calculation of the slag layer, measure the movement time of the electrode from the air-slag interface passage time to the slag-molten metal interface passage time,
Instead of measuring each moving distance of the electrodes,
It is a slag layer thickness and molten metal layer surface level position measuring method which calculates | requires each said moving distance of the said electrode by calculation from the said moving speed and each said moving time of the said electrode.
[0039]
The first slag layer thickness and molten metal layer surface level position measuring device is:
Electrodes,
A container having conductivity and containing molten metal with a slag layer floating on the surface of the molten metal layer;
A fixed point located at a predetermined distance from the container above the opening of the container in the atmospheric layer occupying the upper layer of the slag layer from the molten metal layer through the slag layer. Or an electrode moving means for moving down from the fixed point in the atmospheric layer to the molten metal layer through the slag layer,
A DC power source Vcc having the electrode side as a cathode and a resistor Rx connected in series with the power source are inserted between the electrode and the container, and the values of the DC power source Vcc and the resistor Rx are set to the electrode. A measurement circuit formed by setting the potential of the container to be a potential higher than the reference potential, using the potential of the container as a reference potential when the slag layer is immersed in the slag layer,
A potential measuring means for measuring the potential of the electrode with respect to the reference potential;
For the measurement of the thickness of the slag layer, from the time when the potential measuring means detects, from the time when the reference potential changes to the high potential, until the time when the high potential changes to a lower potential lower than the reference potential, Alternatively, an electrode movement distance measuring means for measuring a slag layer thickness for measuring a movement distance of the electrode from a time point when the low potential is changed to the high potential to a time point when the high potential is changed to the reference potential;
For measuring the distance from the fixed point to the surface of the molten metal layer, from the time when the reference potential detected by the potential measuring means changes from the reference potential to the high potential, or from the fixed point, from the high potential Electrode moving distance measuring means for measuring the molten metal layer surface level position for measuring the moving distance of the electrode up to the time when the reference potential is changed,
Is a slag layer thickness and molten metal layer surface level position measuring device comprising
[0040]
And the second slag layer thickness and the molten metal layer surface level position measuring device,
Electrodes,
A container having conductivity and containing molten metal with a slag layer floating on the surface of the molten metal layer;
Predetermined constant from the container above the opening of the container in the atmospheric layer occupying the upper layer of the slag layer from the molten metal layer, through the slag layer, with a constant moving speed. An electrode moving means for moving up to a fixed point located at a distance, or moving down from the fixed point in the atmospheric layer to the molten metal layer through the slag layer;
A DC power source Vcc having the electrode side as a cathode and a resistor Rx connected in series with the power source are inserted between the electrode and the container, and the values of the DC power source Vcc and the resistor Rx are set to the electrode. A measurement circuit formed by setting the potential of the container to be a potential higher than the reference potential, using the potential of the container as a reference potential when the slag layer is immersed in the slag layer,
A potential measuring means for measuring the potential of the electrode with respect to the reference potential;
For the measurement of the thickness of the slag layer, from the time when the potential measuring means detects, from the time when the reference potential changes to the high potential, until the time when the high potential changes to a lower potential lower than the reference potential, Alternatively, the electrode moving time measuring means for measuring the slag layer thickness for measuring the moving time of the electrode from the time of changing from the low potential to the high potential to the time of changing from the high potential to the reference potential;
For measuring the distance from the fixed point to the surface of the molten metal layer, the potential measuring means detects from the time point when the reference potential changes to the high potential to the fixed point, or from the fixed point to the high potential. An electrode movement time measuring means for measuring the surface level position of the molten metal layer for measuring the movement time of the electrode from the point of change to the reference potential,
Electrode movement distance calculation means for calculating a movement distance of the electrode by calculation from the movement speed of the electrode and each movement time;
Is a slag layer thickness and molten metal layer surface level position measuring device comprising
[0041]
According to each slag layer thickness and molten metal layer surface level position measuring method, or according to the slag layer thickness and molten metal layer surface level position measuring apparatus, the slag layer thickness measuring method or slag layer thickness measurement described above. By using the principle used in the apparatus, not only the slag layer thickness but also the surface level position of the slag layer can be measured.
[0042]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings. Although the present invention is directed to molten metal, the slag layer thickness measuring apparatus according to the first embodiment of the present invention uses molten steel as the molten metal.
FIG. 8 is an explanatory diagram showing the configuration of the slag layer thickness measuring apparatus according to the first embodiment. In FIG. 8, 31 is a converter, 32 is a molten steel layer, 33 is a slag layer, 34 is an atmospheric layer, 35 is an electrode, 36 is a probe, 37 is a lance, 38 is a lance moving device, 39 is an encoder, and 40a is a measuring device. , 41 is a DC power source Vcc, 42 is a resistor Rx, 43 is an electrode potential measuring circuit (analog circuit), 44 is a lance movement control circuit, 45 is an encoder pulse count circuit, 47 is a microcomputer, and 48 is a display.
In the first embodiment, a converter is used as a container for containing molten steel, but a ladle may be used.
[0043]
In FIG. 8, the electrode 35 is held by a probe 36, and the lance 37 that fixes the probe 36 is moved vertically by a lance moving device 38 to move the electrode 35. . The lance moving device 38 includes a motor that can be positioned and controlled, such as a pulse motor and a servo motor, and a device that converts the rotational motion of the rack and pinion into linear motion.
Instead of using the lance moving device 38 having such a configuration, a feed screw mechanism as shown in FIG. 12 may be used. In FIG. 12, a paper probe is used as a substitute for a lance, and the probe is moved up and down by rotating the probe.
[0044]
FIG. 9 shows the structure of the joining portion of the electrode 35, the probe 36, and the lance 37 in FIG. In FIG. 9, the electrode 35 is connected to a contact contact 51 of the probe 36, and a ring contact 52 in contact with the contact contact 51 is connected to an electrode potential measurement circuit (analog circuit) 43. The probe 36 can endure only a short time required for measurement with respect to molten high-temperature molten steel, and needs to be replaced every time measurement is performed, and such a structure is adopted.
In FIG. 8, the converter 31 is generally formed by stacking refractory bricks inside a metal container, and the converter 31 alone does not have conductivity, but accommodates molten steel in the converter 31. As a result, the metal adheres to the inner surface of the converter 31, thereby providing electrical conductivity between the inner surface of the converter 31 and the ground. That is, it is equivalent to the converter 31 being grounded to the ground.
Further, between the ground and the electrode 35, a DC power source Vcc 11 having the electrode 35 side as a cathode and a resistor Rx 12 connected in series with the DC power source 11 are connected. Here, the values of the DC power supply 11 and the resistance Rx12 are set so that the potential of the electrode 5 with respect to the converter 31 having the same potential as the ground becomes a positive potential when the electrode 35 is immersed in the slag layer 33. ing. Specifically, as described above, the resistance Rx12 is set to an extremely large value compared to the internal resistance in the chemical battery characteristics indicated by the slag layer 33. For example, the internal resistance in the battery characteristics indicated by the slag layer 33 is On the other hand, the resistance Rx12 is set to several hundreds of kilo-ohms while it is about several tens to several hundreds of ohms. As a result, as described above, the potential between the electrode 35 and the ground is substantially equal to the electromotive force in the chemical battery characteristics exhibited by the slag layer 33. Since this electromotive force is anodic with respect to the ground, the potential of the electrode 35 becomes a positive potential.
The electrode potential measurement circuit (analog circuit) 43 is a circuit that measures the potential of the electrode 35 using the potential of the converter 31 that is the ground potential as a reference potential. The encoder 39 is interlocked with the lance moving device 38 and generates a pulse for measuring the moving distance when the lance 37 moves up and down, and the encoder pulse count circuit 45 counts this pulse, thereby causing the lance 37 to move. The movement distance of 37 is obtained.
Instead of using the encoder 39, a concavo-convex or black and white striped pattern scale is provided in the moving direction on the side surface of the lance, and a concavo-convex or black and white stripe is generated by moving the lance using a light source and an optical sensor. A method is also conceivable in which the movement distance of the lance is measured by detecting and counting the pattern change.
[0045]
8, the electrode 35 is moved down from the atmospheric layer 34 through the slag layer 33 to the molten steel layer 32, or conversely, from the molten steel layer 32 through the slag layer 33 to the atmospheric layer 34. The thickness of the slag layer 33 is measured using the change in the electrode-container characteristic, which is the electric characteristic between the electrode 35 and the converter 31 as the container, during this period. In one embodiment, the thickness of the slag layer 33 is measured by ascending and moving from the molten steel layer 32 through the slag layer 33 to the atmospheric layer 34.
In this case, the change in the potential of the electrode 35 with the potential of the converter 31 having the same potential as the ground as the reference potential is as shown in FIG.
In FIG. 5, when the measurement is started at the time Ta and the electrode 35 is located in the molten steel layer 32, Va is 0 (V). At the time Tb when the electrode 35 moves from the molten steel layer 32 to the slag layer 33, that is, when the electrode 35 passes through the molten steel-slag interface, Vb becomes a positive potential. Further, at the time Tc when the electrode 35 moves from the slag layer 33 to the atmospheric layer 34, that is, when the electrode 35 passes through the slag-atmosphere interface, Vc becomes −Vcc (V), which is a negative potential. Therefore, the distance traveled by the electrode 35, that is, the distance traveled by the lance 37 is counted by the encoder pulse count circuit 45, and the time when the potential of the electrode 35 changes from 0 (V) to a positive potential, and the positive potential. Is detected by the electrode potential measuring circuit (analog circuit) 43, and the output signals of the encoder pulse count circuit 45 and the electrode potential measuring circuit (analog circuit) 43 are input to the microcomputer 47 during this period. Thus, the thickness of the slag layer is obtained, and the situation is displayed on the display 48.
[0046]
In the measurement apparatus described above, the movement distance of the electrode 35 is directly obtained using the pulse output from the encoder 39, but there is also a method of obtaining it by calculation from the movement speed and movement time of the electrode. In this method, the encoder 39 and the encoder pulse count circuit 45 are removed from FIG. 8, the moving speed of the electrode 35 is set to a predetermined constant speed, and the electrode potential measurement circuit (analog circuit) 43 The point of passage through the slag-atmosphere interface is detected, and individual signals are input to the microcomputer 47. The microcomputer 47 obtains the moving time of the electrode 35, calculates the moving distance of the electrode 35 from the moving time and the moving speed of the electrode 35, and obtains the thickness of the slag layer.
In this method, the moving speed of the electrode is determined in advance, and the thickness of the slag layer is obtained by using this moving speed for calculation, but the moving speed of the electrode is determined as described above without determining the moving speed of the electrode. Thus, the measurement may be performed using two electrodes as shown in FIG.
[0047]
In the method of obtaining the moving distance from the moving time and moving speed of the electrode 35, the change in the potential of the electrode 35 with the potential of the converter 31 having the same potential as the ground as the reference potential is as shown in FIG. Become. In the slag layer thickness measuring apparatus using this method, the change of the potential can be displayed on the display provided in the measuring apparatus, and the calculation result of the slag layer thickness can be displayed. FIG. 10 shows a display example in the slag layer thickness measuring apparatus in this case. 11A, 11B, 11C, and 11D show examples of changes in the potential of the electrode 35 in such a case.
[0048]
In the above measuring apparatus, the electrode 35 is moved upward from the molten steel layer 32 through the slag layer 33 to the atmospheric layer 34, but the electrode 35 is lowered from the atmospheric layer 34 through the slag layer 33 to the molten steel layer 32. Even if it is moved, the thickness of the slag layer 33 can be similarly known.
Further, in the above measuring apparatus, the electrode 35 is moved up and down in the vertical direction, but may be moved obliquely with respect to the slag layer 33. In this case, the thickness of the slag layer can be obtained by calculation from the tilted angle and the moving distance of the electrode.
[0049]
According to the above measuring apparatus, as can be seen from FIG. 11, the change in the potential of the electrode 35 is 0 (V) which is the reference potential, a plus potential which is higher than the reference potential, and the reference potential. Since the change is to a negative potential that is a lower potential lower than the potential, these changes can be accurately detected, and the movement distance of the electrode 35 is accurately obtained based on these detections. Therefore, the thickness of the slag layer 33 can be accurately known.
Even if the impedance between the electrode 35 and the container 31 changes due to the contact resistance of a connector or the like connected to the electrode 35, the change in the potential of the electrode 35 is higher than the reference potential and the reference potential. Since there is no change in the electric potential and any of the electric potential and a lower electric potential lower than the reference electric potential, the measurement method using the above-described measuring apparatus does not affect the influence of the impedance change between the electrode 35 and the container 31. This is a measurement method that is difficult to receive.
[0050]
In the first embodiment, as described above, molten steel is targeted. However, the contents described above can also be applied to a case where molten metal is generally targeted.
[0051]
In the slag layer thickness measuring apparatus that measures the slag layer thickness of molten steel, it is recommended that the electrode material be an iron alloy containing at least one of Mo, Co, Cr, and Mn. In the slag layer thickness measuring apparatus described above, the molten metal in the container is at a high temperature, and the electrode immersed in the molten metal melts over time. Therefore, it is desirable to make the time until melting as long as possible. However, in this respect, the above alloy is difficult to melt and is excellent as an electrode material.
[0052]
In the slag layer thickness measuring apparatus described above, when measuring the thickness of the slag layer, the electrode used for measuring the oxygen concentration may be used in combination with the molten steel electrode of the oxygen probe. By doing so, the thickness of the slag layer and the oxygen concentration can be measured at the same time, and the electrodes can be used together, so that the cost of the measuring device can be reduced.
[0053]
In the slag layer thickness measuring apparatus described above, the lower tip position of the electrode used in combination with the molten steel electrode of the oxygen probe and the zirconia electrode of the oxygen probe are aligned, and the parts other than both tip parts are protected with a quartz tube or the like. It may be used by covering with a pipe. By doing so, it is possible to prevent the slag from adhering to both the electrode and the zirconia electrode of the oxygen probe, and simultaneously measure the thickness of the slag layer and the oxygen concentration. In addition, since the electrodes can be used in combination, the cost of the measuring apparatus can be reduced.
[0054]
Moreover, in the slag layer thickness measuring apparatus mentioned above, you may make it use an electrode attached to a molten steel temperature measurement probe. By doing in this way, since the measurement of the thickness of a slag layer and the measurement of molten steel temperature can be performed simultaneously and an electrode can be used together, the cost of the measuring device can be reduced.
[0055]
As described above, in a vessel containing molten steel, such as a converter, a vacuum tank provided with a dip tube at the bottom is disposed above the slag floating on the molten steel, and the dip tube is immersed in the molten steel to provide a vacuum. The molten steel is taken into the tank and Ca or the like is added to agglomerate particles of the slag component in the molten steel, thereby making it easier to remove the slag component in the molten steel. In this case, it is necessary to cool the dip tube with water, and if this cooling water and molten steel come into contact with each other, there is a risk of explosion, so position control to keep the height from the slag surface of the vacuum chamber constant is necessary. Therefore, it is necessary to measure the surface level position of the molten steel layer. Therefore, next, along with the measurement of the slag layer thickness, the surface level position of the molten steel layer, that is, above the opening of the container containing the molten metal, the molten steel layer from a fixed point located a predetermined distance away from the container. A slag layer thickness and molten steel layer surface level position measuring apparatus which is a second embodiment of the present invention for measuring the distance to the surface will be described. The position of the vacuum chamber can be controlled by reflecting the change in the distance from the fixed point to the surface of the molten steel layer measured by this device in the positional relationship between the fixed point and the vacuum chamber.
[0056]
FIG. 15 is an explanatory diagram showing the configuration of the slag layer thickness and molten steel layer surface level position measuring apparatus according to the second embodiment of the present invention. 15, the same numbers as those in FIG. 8 are the same as those in FIG. 8 differs from FIG. 8 in that a vacuum chamber 24 having a dip tube 25 at the bottom is disposed above the converter 31 and a fixed point detection mark 28 for detecting a state where the electrode 35 is located at a fixed point 49 is provided. A light source 27 and a sensor 29 for detecting the fixed point detection mark 28 are provided on the side surface of the lance 37, a fixed point detection circuit 46 is provided, and an output of the sensor 29 is input to the fixed point detection circuit 46. The output of the fixed point detection circuit 46 is input to the microcomputer 47. Also in the second embodiment, as in the first embodiment, the slag layer is moved up from the molten steel layer 32 through the slag layer 33 to the atmosphere layer 34, and the thickness of the slag layer and the fixed point to the surface of the molten steel layer. Measure distance.
[0057]
In this case, the method for measuring the thickness of the slag layer is exactly the same as in the first embodiment. Further, the distance from the fixed point to the surface of the molten steel layer is such that when the electrode 35 moves from the molten steel layer 32 to the slag layer 33, that is, from the time when the molten steel-slag interface passes to the fixed point, the electrode 35, What is necessary is just to measure the distance which the lance 37 moved. The time when the molten steel-slag interface passes is the time when the potential of the electrode 35 changes from the reference potential to the high potential, and the time when the potential reaches the fixed point is the time when the sensor 29 detects the fixed point detection mark 28. Thus, these detection signals are input to the microcomputer 47 through the fixed point detection circuit 46, and the microcomputer 47 determines the thickness of the slag layer and the molten steel layer from the fixed point in the same manner as in the first embodiment. The distance to the surface is calculated and the situation is displayed on the display 48.
[0058]
Also in the slag layer thickness and molten steel layer surface level position measuring apparatus according to the second embodiment, the measurement may be performed by moving the electrode downward as in the first embodiment. Further, the moving distance of the electrode 35 may be obtained by calculation from the moving speed and moving time of the electrode. Therefore, the moving speed of the electrode may be measured using two electrodes as shown in FIG. The electrode may be moved obliquely with respect to the slag layer. Moreover, you may use a ladle as a container which accommodates molten steel. Moreover, not only molten steel but a general molten metal can also be used.
[0059]
According to the slag layer thickness and molten steel layer surface level position measuring apparatus according to the second embodiment described above, by using the principle used in the above slag layer thickness measuring apparatus, it is only possible to measure the slag layer thickness. First, the surface level position of the slag layer can be measured.
[0060]
In both the first and second embodiments described above, the DC power source 11 uses the electrode 35 side as a cathode, but can be measured in principle with the electrode 35 side as an anode. That is, in FIGS. 8 and 15, even if the polarity of Vcc is reversed, the slag layer thickness is measured by utilizing the fact that the electrical characteristics of the slag layer are different from those of the lower molten steel and the upper atmosphere. A measurement of the surface level position of the layer can be performed.
[0061]
【Effect of the invention】
According to the slag layer thickness measuring method according to claim 1 or 2, conductivity, power generation, or insulation, which is a change in electrode-to-container characteristic, which is an electrical characteristic between the electrode and the container. Measurements are made using changes between each property. This change is not between homogeneous things like impedance changes, but between heterogeneous ones, so you can capture the change clearly and accurately measure the thickness of the slag layer It is possible to provide a method for measuring the thickness of the slag layer.
In addition, since the electrode itself is not expensive in cost, it may be replaced every time measurement is performed, and it is not necessary to prevent damage to the electrode. Therefore, according to these slag layer thickness measurement methods, the cost is low. A method for measuring the slag layer thickness can be provided.
[0062]
According to the method for measuring the thickness of the slag layer according to claim 3 or claim 4, the change in the potential of the electrode is any one of a reference potential, a high potential higher than the reference potential, and a low potential lower than the reference potential. Because the change can be digitally captured, the change can be detected accurately, and the movement distance of the electrode can be accurately obtained based on these detections. It is possible to provide a slag layer thickness measuring method capable of accurately knowing the thickness of the slag layer.
In addition, even if the impedance between the electrode and the container changes due to the contact resistance of the connector on the way from the electrode to the circuit for measuring this potential, the change in the electrode potential changes from the reference potential and the reference potential. Therefore, this measurement method is affected by the change in impedance between the electrode and the container. A difficult slag layer thickness measurement method can be provided.
[0063]
According to the slag layer thickness measuring method of the fifth aspect, it is not necessary to directly measure the moving distance of the electrode, and it is possible to provide a slag layer thickness measuring method that makes the measuring method simple.
[0064]
According to the slag layer thickness measuring apparatus according to claim 6, the change in the potential of the electrode is changed to any one of a reference potential, a high potential higher than the reference potential, and a low potential lower than the reference potential. Since changes can be captured digitally, changes can be detected accurately, and the movement distance of the electrodes can be accurately determined based on these detections. It is possible to provide a slag layer thickness measuring apparatus that can accurately know the thickness.
In addition, even if the impedance between the electrode and the container changes due to the contact resistance of the connector or the like connected to the electrode, the change in the electrode potential is caused by the reference potential, a higher potential higher than the reference potential, Since it is still a change to a low potential lower than the reference potential, according to this measurement method, the slag layer thickness measuring device is not easily affected by the impedance change between the electrode and the container. Can provide.
[0065]
According to the slag layer thickness measuring apparatus of Claim 7, in addition to the effect of the slag layer thickness measuring apparatus of Claim 6, it has the following effect. That is, according to this slag layer thickness measuring apparatus, it is not necessary to directly measure the moving distance of the electrode, and therefore it is possible to provide a slag layer thickness measuring apparatus in which the measuring method is simplified.
[0066]
According to the slag layer thickness measuring apparatus of the eighth aspect, it is possible to provide a slag layer thickness measuring apparatus that does not require a predetermined moving speed of the electrode.
[0067]
According to the slag layer thickness measuring apparatus of Claim 9, the slag layer thickness measuring apparatus for molten steel can be provided.
[0068]
According to the slag layer thickness measuring device of the tenth aspect, it is possible to provide a slag layer thickness measuring device which is difficult to melt the electrode when measuring the slag layer thickness.
[0069]
According to the slag layer thickness measuring apparatus of the eleventh aspect, it is possible to simultaneously measure the thickness of the slag layer and the oxygen concentration and to use the electrode together, so that the cost of the measuring apparatus is reduced. be able to.
[0070]
According to the slag layer thickness measuring apparatus of claim 12, it is possible to prevent slag from adhering to both the electrode and the zirconia electrode of the oxygen probe, and at the same time, measuring the thickness of the slag layer. Since the oxygen concentration can be measured and the electrodes can be used in combination, the cost of the measuring apparatus can be reduced.
[0071]
According to the slag layer thickness measuring apparatus according to claim 13, it is possible to simultaneously measure the thickness of the slag layer and the molten steel temperature, and to use the electrode together, so that the cost of the measuring apparatus is reduced. be able to.
[0072]
The slag layer thickness and molten metal layer surface level position measuring method according to claim 14 to 18, or the slag layer thickness and molten metal layer surface level position measuring apparatus according to claim 19 and claim 20. Therefore, by using the principle used in the above-described slag layer thickness measuring method or slag layer thickness measuring apparatus, not only the slag layer thickness but also the surface level position of the molten metal layer can be measured. it can.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing the principle of a first slag layer thickness measuring method of the present invention.
FIG. 2 is an explanatory view showing the principle of a third slag layer thickness measuring method of the present invention.
FIG. 3 is an equivalent circuit diagram of FIG.
4 is an equivalent circuit diagram of FIG. 3, where (a) is when the electrode is located in the molten metal layer, (b) is when the electrode is located in the slag layer, and (c) is when the electrode is in the atmosphere. The case where it is located in a layer is shown.
FIG. 5 is a diagram showing a change in the potential of the electrode with the potential of the container as a reference potential when the electrode is moved up from the molten metal layer through the slag layer to the atmospheric layer.
6A and 6B are explanatory diagrams of a method for measuring the moving speed of an electrode using two electrodes, in which FIG. 6A shows the principle and FIG. 6B shows a change in potential of each electrode.
FIG. 7 is an explanatory diagram showing the principle of the first slag layer thickness and molten metal layer surface level position measuring method of the present invention.
FIG. 8 is an explanatory diagram showing the configuration of the slag layer thickness measuring apparatus according to the first embodiment of the present invention.
FIG. 9 is an explanatory diagram showing the structure of the electrode, probe, and lance joints in FIG.
FIG. 10 is a display example of the display of the slag layer thickness measuring apparatus using the method of obtaining the moving distance from the moving time and moving speed of the electrode according to the first embodiment.
11 (a), (b), (c), and (d) in the slag layer thickness measuring apparatus using the method of obtaining the moving distance from the moving time and moving speed of the electrode of the first embodiment. Display example of changes in electrode potential
FIG. 12 is a sectional view of a probe employing a feed screw mechanism.
FIG. 13 is a configuration diagram of a slag layer thickness measuring device used in combination with an oxygen concentration measuring device (1).
FIG. 14 is a configuration diagram of a slag layer thickness measuring device used in combination with an oxygen concentration measuring device (2).
FIG. 15 is an explanatory diagram showing the configuration of a slag layer thickness and molten steel layer surface level position measuring apparatus according to a second embodiment of the present invention.
[Explanation of symbols]
1 container
2 Molten metal layer
3 Slag layer
4 atmospheric layers
5 electrodes
6 Slag layer thickness
7 When the molten metal-slag interface passes
8 Slag-atmosphere interface passage time
9 Fixed points
10 Distance from fixed point to surface of molten metal layer
11 DC power supply Vcc
12 Resistance Rx
13 Potential measurement means
19 selector switch
21 electrodes
22 electrodes
23 Measuring device
25 vacuum chamber
26 Immersion tube
27 Light source
28 Fixed point detection mark
29 sensors
31 Converter
32 Molten steel layer
33 Slag layer
34 Atmosphere
35 electrodes
36 probes
37 Lance
38 Lance moving device
39 Encoder
40a, 40b Measuring device
41 DC power supply Vcc
42 Resistance Rx
43 Electrode potential measurement circuit (analog circuit)
44 Lance movement control circuit
45 Encoder pulse count circuit
46 Fixed point detection circuit
47 Microcomputer
48 display
49 Fixed point
51 Contact
52 Ring contactor
61 Lance (probe)
62 Rifle groove inner diameter
63 Lance holder
64 Lance holder mounting base
65 electrodes
71 Zirconia electrode
72 Molten steel electrode
73 Oxygen probe
74 Oxygen concentration measuring instrument
75 Slag layer thickness measuring instrument
76 Quartz tube

Claims

In the method of measuring the thickness of the slag layer of the molten metal in which the slag layer floats on the surface of the molten metal layer, the electrode is moved up from the molten metal layer to the atmospheric layer that occupies the upper layer of the slag layer. Then, the electrode-container characteristic, which is an electrical characteristic between the container containing the molten metal and having conductivity and the electrode, is monitored, and the electrode-container characteristic indicates that the electrode is the molten metal. Molten metal at the time when the electrode moves to the slag layer and shifts to the power generation property due to the slag layer functioning as an electrolyte from the conductivity due to the molten metal layer when immersed in the layer- The slag-atmosphere when the slag interface passes and when the electrode escapes from the slag layer to the atmospheric layer, and the electrode-container characteristic shifts from the power generation to the insulating property due to the presence of the atmospheric layer interface The slag layer thickness is detected as the thickness of the slag layer by detecting the excess time and measuring the distance traveled by the electrode from the molten metal-slag interface passing time to the slag-atmosphere interface passing time. Measuring method,
A DC power source Vcc having the electrode side as a cathode and a resistor Rx connected in series with the power source are inserted between the electrode and the container, and the values of the DC power source Vcc and the resistor Rx are set to the electrode. Is set so that the potential of the electrode becomes a positive potential when the potential of the container is set to a reference potential of 0 V when the electrode is immersed in the slag layer,
The electrode is moved upward from the molten metal layer to the atmospheric layer, and the potential of the electrode with respect to the reference potential of 0 V is measured.
As the time when the molten metal-slag interface passes, the time when the potential of the electrode changes from the reference potential 0V to the plus potential ,
Further, as the time when the slag-atmosphere interface passes, the time when the potential of the electrode changes from the positive potential to the negative potential ,
Luz rag layer thickness measuring method detects.

In the method of measuring the thickness of the slag layer of the molten metal in which the slag layer floats on the surface of the molten metal layer, the electrode moves down from the atmospheric layer occupying the upper layer of the slag layer to the molten metal layer through the slag layer Then, the electrode-container characteristic, which is an electrical characteristic between the container containing the molten metal and having conductivity and the electrode, is monitored, and the electrode-container characteristic indicates that the electrode is in the atmosphere layer. When the electrode passes through the air-slag interface, which is a time when the electrode is immersed in the slag layer to shift to power generation due to the interposition of the slag layer functioning as an electrolyte, Is moved from the slag layer to the molten metal layer, and the electrode-container characteristic passes through the slag-molten metal interface, which is a point at which the power generation property shifts to the conductivity due to the intervention of the molten metal layer. Inspection And a slag layer thickness measurement method that measures the distance traveled by the electrode from the time of passage through the air-slag interface to the time of passage through the slag-molten metal interface to obtain the thickness of the slag layer. And
A DC power source Vcc having the electrode side as a cathode and a resistor Rx connected in series with the power source are inserted between the electrode and the container, and the values of the DC power source Vcc and the resistor Rx are set to the electrode. Is set so that the potential of the electrode becomes a positive potential when the potential of the container is set to a reference potential of 0 V when the electrode is immersed in the slag layer,
The electrode is moved down from the atmospheric layer to the molten metal layer, and the potential of the electrode with respect to the reference potential of 0 V is measured.
As the time when the air-slag interface passes, the time when the potential of the electrode changes from a negative potential to the positive potential ,
In addition, as the time of passage through the slag-molten metal interface, the time when the potential of the electrode changes from the positive potential to the reference potential 0V ,
Luz rag layer thickness measuring method detects.

While making the moving speed of the upward movement or the downward movement of the electrode constant,
When using a method of moving the electrode upward from the molten metal layer to the atmospheric layer, measure the movement time of the electrode from the molten metal-slag interface passage time to the slag-atmosphere interface passage time,
When using the method of moving the electrode down from the atmosphere layer to the molten metal layer, measuring the movement time of the electrode from the time of passing the atmosphere-slag interface to the time of passing the slag-molten metal interface,
Instead of measuring the travel distance of the electrode,
The slag layer thickness measuring method according to claim 1 or 2 , wherein the moving distance of the electrode is obtained by calculation from the moving speed and the moving time of the electrode.

Electrodes,
A container having conductivity and containing molten metal with a slag layer floating on the surface of the molten metal layer;
Electrode movement for moving the electrode up from the molten metal layer through the slag layer to the atmospheric layer occupying the upper layer of the slag layer, or moving down from the atmospheric layer through the slag layer to the molten metal layer Means,
A DC power source Vcc having the electrode side as a cathode and a resistor Rx connected in series with the power source are inserted between the electrode and the container, and the values of the DC power source Vcc and the resistor Rx are determined by the electrode. When immersed in the slag layer, the potential of the container is set to a reference potential of 0 V ,
A measurement circuit formed by setting the potential of the electrode to be a positive potential ;
A potential measuring means for measuring the potential of the electrode with respect to the reference potential of 0 V ;
Was detected the potential measuring means, from the time that varies from the reference voltage 0V to the positive potential, up to the point changes from the positive potential to the negative potential, or from the time of changing from the negative potential to the positive potential, From the positive potential to the reference potential 0V
Electrode moving distance measuring means for measuring the moving distance of the electrode up to the point of change to
A slag layer thickness measuring device comprising:

Electrodes,
A container having conductivity and containing molten metal with a slag layer floating on the surface of the molten metal layer;
The electrode is moved up from the molten metal layer through the slag layer to the atmospheric layer occupying the upper layer of the slag layer, or the molten metal passes from the atmospheric layer through the slag layer, with a constant moving speed. An electrode moving means for moving down to the layer;
A DC power source Vcc having the electrode side as a cathode and a resistor Rx connected in series with the power source are inserted between the electrode and the container, and the values of the DC power source Vcc and the resistor Rx are set to the electrode. A measurement circuit formed by setting the potential of the container to be a positive potential when the potential of the container is set to a reference potential of 0 V when the slag layer is immersed in the slag layer;
A potential measuring means for measuring the potential of the electrode with respect to the reference potential of 0 V ;
Was detected the potential measuring means, from the time that varies from the reference voltage 0V to the positive potential, up to the point changes from the positive potential to the negative potential, or from the time of changing from the negative potential to the positive potential, An electrode movement time measuring means for measuring the movement time of the electrode from the plus potential to the time point when the reference potential changes to 0 V ;
An electrode moving distance calculating means for calculating a moving distance of the electrode by calculation from the moving speed and the moving time of the electrode;
A slag layer thickness measuring device comprising:

The slag layer thickness measuring apparatus according to claim 4 or 5 , wherein the molten metal is molten steel.

The slag layer thickness measuring apparatus according to claim 6 , wherein the electrode is made of an iron alloy containing at least one of Mo, Co, Cr, and Mn.

The slag layer thickness measuring apparatus according to claim 6 or 7 , wherein the electrode is used in combination with a molten steel electrode of an oxygen probe for measuring oxygen concentration.

The slag layer thickness according to claim 8 , wherein the lower tip positions of the electrode and the zirconia electrode of an oxygen probe for measuring oxygen concentration are aligned, and a portion other than both tip portions is covered with a protective pipe such as a quartz tube. Measuring device.

The slag layer thickness measuring apparatus according to any one of claims 6 to 9 , wherein the electrode is attached to a molten steel temperature measuring probe.

From the fixed point located at a predetermined distance from the container to the surface of the molten metal layer above the opening of the container that is electrically conductive and contains molten metal in which the slag layer floats on the surface of the molten metal layer In the method for measuring the distance and the thickness of the slag layer, the electrode is moved up from the molten metal layer through the slag layer to the fixed point in the atmospheric layer occupying the upper layer of the slag layer, and the container The electrode-container characteristic, which is an electrical characteristic between the electrode and the container, is monitored, and this electrode-container characteristic is due to the interposition of the molten metal layer when the electrode is immersed in the molten metal layer. From the conductivity, when the electrode moves to the slag layer and shifts to power generation due to the interposition of the slag layer functioning as an electrolyte, the molten metal-slag interface passing time, and the electrode from the slag layer to the large Slag-at-air interface passing time when the electrode-container characteristic shifts from the power generation property to the insulating property due to the presence of the atmospheric layer, and the molten metal-slag is detected. From the interface passing time to the slag-atmosphere interface passing time, the distance traveled by the electrode is measured to obtain the thickness of the slag layer, and from the molten metal-slag interface passing time to the fixed point, A method for measuring a slag layer thickness and a molten metal layer surface level position as a distance from the fixed point to the surface of the molten metal layer by measuring a moving distance by which the electrode moves
A DC power source Vcc having the electrode side as a cathode and a resistor Rx connected in series with the power source are inserted between the electrode and the container, and the values of the DC power source Vcc and the resistor Rx are When the electrode is immersed in the slag layer, the potential of the electrode is set to a positive potential with the potential of the container being a reference potential of 0 V, and
The electrode is moved upward from the molten metal layer to the atmospheric layer, and the potential of the electrode with respect to the reference potential of 0 V is measured.
As the time when the molten metal-slag interface passes, the time when the potential of the electrode changes from the reference potential 0 V to the plus potential ,
Further, as the time when the slag-atmosphere interface passes, the time when the potential of the electrode changes from the positive potential to the negative potential ,
Detect and such absence rag layer thickness and the molten metal layer surface level position measuring method.

From the fixed point located at a predetermined distance from the container to the surface of the molten metal layer above the opening of the container that is electrically conductive and contains molten metal in which the slag layer floats on the surface of the molten metal layer In the method for measuring the distance and the thickness of the slag layer, the electrode is moved down from the fixed point in the atmospheric layer occupying the upper layer of the slag layer to the molten metal layer through the slag layer, The electrode-container property, which is an electrical property between the electrode containing the molten metal and the electrically conductive container, is monitored, and the electrode-container property is determined when the electrode is in the atmospheric layer. From the insulating property due to the presence of air in the atmosphere, the time when the electrode is immersed in the slag layer and shifts to the power generation property due to the presence of the slag layer functioning as an electrolyte, and the time when the electrode passes the slag From layer Moving to the molten metal layer, and detecting the slag-molten metal interface passage time, which is the time when the electrode-container characteristic shifts from the power generation property to conductivity due to the intervention of the molten metal layer, From the fixed point to the point of passage through the slag-molten metal interface, the distance traveled by the electrode is measured to obtain the distance from the fixed point to the surface of the molten metal layer, and from the point of passage through the atmosphere-slag interface. A method for measuring a slag layer thickness and a molten metal layer surface level position as a thickness of the slag layer by measuring a moving distance by which the electrode has moved by the time of passing through the slag-molten metal interface,
A DC power source Vcc having the electrode side as a cathode and a resistor Rx connected in series with the power source are inserted between the electrode and the container, and the values of the DC power source Vcc and the resistor Rx are When the electrode is immersed in the slag layer, the potential of the electrode is set to a positive potential with the potential of the container being a reference potential of 0 V, and
The electrode is moved down from the atmospheric layer to the molten metal layer, and the potential of the electrode with respect to the reference potential of 0 V is measured.
As the time of passage through the air-slag interface, the time when the potential of the electrode changes from a negative potential to the positive potential ,
In addition, as the time of passage through the slag-molten metal interface, the time when the potential of the electrode changes from the positive potential to the reference potential 0V ,
Detect and such absence rag layer thickness and the molten metal layer surface level position measuring method.

While making the moving speed of the upward movement or the downward movement of the electrode constant,
When using the method of moving up the electrode from the molten metal layer to the atmospheric layer,
For calculating the thickness of the slag layer, measure the movement time of the electrode from the molten metal-slag interface passage time to the slag-atmosphere interface passage time,
For the calculation of the distance from the fixed point to the surface of the molten metal layer, measure the movement time of the electrode from the molten metal-slag interface passing time to the fixed point,
When using a method of moving down the electrode from the atmospheric layer to the molten metal layer,
For calculating the distance from the fixed point to the surface of the molten metal layer, measure the movement time of the electrode from the fixed point to the slag-molten metal interface passing time,
For the thickness calculation of the slag layer, measure the movement time of the electrode from the air-slag interface passage time to the slag-molten metal interface passage time,
Instead of measuring each moving distance of the electrodes,
The slag layer thickness and molten metal layer surface level position measuring method according to claim 11 or 12 , wherein each moving distance of the electrode is obtained by calculation from the moving speed of the electrode and each moving time. .

Electrodes,
A container having conductivity and containing molten metal with a slag layer floating on the surface of the molten metal layer;
A fixed point located at a predetermined distance from the container above the opening of the container in the atmospheric layer occupying the upper layer of the slag layer from the molten metal layer through the slag layer. Or an electrode moving means for moving down from the fixed point in the atmospheric layer to the molten metal layer through the slag layer,
A DC power source Vcc having the electrode side as a cathode and a resistor Rx connected in series with the power source are inserted between the electrode and the container, and the values of the DC power source Vcc and the resistor Rx are set to the electrode. A measurement circuit formed by setting the potential of the container to be a positive potential when the potential of the container is set to a reference potential of 0 V when the slag layer is immersed in the slag layer;
A potential measuring means for measuring the potential of the electrode with respect to the reference potential of 0 V ;
For the thickness measurement of the slag layer, the potential measuring unit detects, from the time that varies from the reference voltage 0V to the positive potential, up to the point changes from the positive potential to the negative potential, or the negative potential An electrode moving distance measuring means for measuring a slag layer thickness for measuring a moving distance of the electrode from a time point when changing from the positive potential to the positive potential to a time point when changing from the positive potential to the reference potential of 0 V ;
For measuring the distance from the fixed point to the surface of the molten metal layer, from the time point when the reference potential 0V detected by the potential measuring means changes from the reference potential 0V to the positive potential to the fixed point, or from the fixed point to the positive potential An electrode moving distance measuring means for measuring the surface level position of the molten metal layer for measuring the moving distance of the electrode from the time when the reference potential is changed to 0 V ,
A slag layer thickness and a molten metal layer surface level position measuring device comprising:

Electrodes,
A container having conductivity and containing molten metal with a slag layer floating on the surface of the molten metal layer;
Predetermined constant from the container above the opening of the container in the atmospheric layer occupying the upper layer of the slag layer from the molten metal layer, through the slag layer, with a constant moving speed. An electrode moving means for moving up to a fixed point located at a distance, or moving down from the fixed point in the atmospheric layer to the molten metal layer through the slag layer;
A DC power source Vcc having the electrode side as a cathode and a resistor Rx connected in series with the power source are inserted between the electrode and the container, and the values of the DC power source Vcc and the resistor Rx are set to the electrode. A measurement circuit formed by setting the potential of the container to be a positive potential when the potential of the container is set to a reference potential of 0 V when the slag layer is immersed in the slag layer;
A potential measuring means for measuring the potential of the electrode with respect to the reference potential of 0 V ;
For the thickness measurement of the slag layer, the potential measuring unit detects, from the time that varies from the reference voltage 0V to the positive potential, up to the point changes from the positive potential to the negative potential, or the negative potential wherein from the time the changes to the plus potential, said from the positive potential of up to the point that changes to the reference potential 0V, the slag layer thickness measuring electrode moving time measuring means for measuring the travel time of the electrode from,
For measuring the distance from the fixed point to the surface of the molten metal layer, the potential measuring means detects the time from the change from the reference potential 0 V to the positive potential to the fixed point, or from the fixed point to the positive point. said reference potential 0V up to the point of changing the molten metal layer surface level position measuring electrode moving time measuring means for measuring the travel time of the electrode from the potential,
Electrode movement distance calculation means for calculating a movement distance of the electrode by calculation from the movement speed of the electrode and each movement time;
A slag layer thickness and a molten metal layer surface level position measuring device comprising: