JP4614154B2

JP4614154B2 - Pusher-type tunnel furnace, and base plate and sheath used in the tunnel furnace

Info

Publication number: JP4614154B2
Application number: JP2001002512A
Authority: JP
Inventors: 直田中; 泰章矢野; 嘉孝木村
Original assignee: Tokai Konetsu Kogyo Co Ltd
Current assignee: Tokai Konetsu Kogyo Co Ltd
Priority date: 2000-08-30
Filing date: 2001-01-10
Publication date: 2011-01-19
Anticipated expiration: 2021-01-10
Also published as: JP2002147963A

Description

【０００１】
【発明の属する技術分野】
本発明は、セラミックスの粉体、粒体、小型成形品、セラミックス材料を含むチップなどの被処理品をサヤなどの治具に積載して、プッシャーによって加熱炉内に押し込み、搬送させて焼成処理または焼結処理を行うためのプッシャー式トンネル炉の改良、および当該トンネル炉で用いる台板およびサヤに関する。
【０００２】
【従来の技術】
従来、上記の被処理品を、焼成、焼結のために１０００℃以上の高温で熱処理する場合には、一般に、例えば正方形や円形のサヤに被処理品を１０〜２０ｍｍの薄さで装填し、これらのサヤを台板上に２、３段積み重ね、トンネル炉内にプッシャーで連続式に押し込んで炉内を搬送させ、十分な時間をかけて熱処理を行う方式が行われている。
【０００３】
しかしながら、この方式では、被処理品の加熱を均一に行うために、被処理品の充填厚さを薄くせざるを得ないため、必要な処理能力に対して一般的に長めの炉長を必要とし、このため、設備費の点から経済的ではなく、さらに、サヤやセッターなどの焼成治具の重量が炉長に比例して大きくなり、その分無駄なエネルギーを消費するという問題があった。
【０００４】
【発明が解決しようとする課題】
本発明は、プッシャー式トンネル炉における上記従来の問題点を解消するために、サヤおよび台板の構造について再検討を行った結果としてなされたものであり、その目的は、とくに、１０００℃以上の高温域において、セラミックスの粉体、粒体、小型成形品、セラミックス材料を含むチップなどを、比較的短い炉長で均一に加熱処理することができ且つ高いエネルギー利用効率での焼成を可能とするプッシャー式トンネル炉、および当該プッシャー式トンネル炉で用いる台板およびサヤを提供することにある。
【０００５】
【課題を解決するための手段】
上記の目的を達成するための請求項１によるプッシャー式トンネル炉は、被処理物を装填したサヤを順次炉内に押し込み、炉内を搬送させるためのプッシャーを備えたプッシャー式トンネル炉において、サヤとして中空円筒形状のサヤを用い、炉床に開口部を有する台板を連続的に並置し、並置された台板列の多数の開口部内にそれぞれ前記中空円筒形状のサヤがその中心軸が搬送方向と垂直となるよう炉床に載置され、台板がプッシャーの推力により搬送されると同時に、中空円筒形状のサヤが前記開口部内で回動しながら台板と共に搬送されるよう構成したことを特徴とする。
【０００７】
請求項２によるプッシャー式トンネル炉で用いる台板は、請求項１記載のプッシャー式トンネル炉で用いる台板であって、中央部に中空円筒形状のサヤを載置するための長方形状の開口部を設けた枠体からなる台板であって、前記開口部を構成する辺のうち、台板の炉内搬送方向に垂直な辺はサヤの軸方向の長さより長く、台板の炉内搬送方向に平行な辺は下記式で表されるＤより大きい長さに形成されることを特徴とする。
Ｄ＝２（２ＲＨ−Ｈ^２）^１／２（但し、Ｒ：中空円筒形状のサヤの半径、Ｈ：台板の厚さ）
【０００８】
請求項３によるプッシャー式トンネル炉で用いる台板は、請求項２において、前記枠体からなる台板における台板の炉内搬送方向に垂直な枠の一方を欠いたコ字枠状に形成したことを特徴とする。
【０００９】
請求項４によるプッシャー式トンネル炉で用いるサヤは、請求項１記載のプッシャー式トンネル炉で用いるサヤであって、前記中空円筒形状のサヤにおいて、円筒の内壁面に円筒軸方向に平行な複数の突条が設けられ、円筒の端部の少なくとも一方が被処理物の装入、排出のために開放可能に構成されていることを特徴とする。
【００１０】
請求項５によるプッシャー式トンネル炉は、被処理物を装填したサヤを順次炉内に押し込み、炉内を搬送させるためのプッシャーを備えたプッシャー式トンネル炉において、サヤとして中空円筒形状の本体の両端に円筒状突起をそなえたサヤを用い、該サヤの搬送方向にサヤの両端の円筒状突起を支受するための平行なレールを炉内に配設し、炉床に開口部を有する台板を連続的に並置し、並置された台板列の多数の開口部内にそれぞれ前記中空円筒形状のサヤがその中心軸が搬送方向と垂直となるよう載置されると共に、サヤの両端の円筒状突起をレール上に載置して、サヤが炉床に接触しないよう保持されるようにし、台板がプッシャーの推力により搬送されると同時に、中空円筒形状のサヤが前記開口部内で回動しながら台板と共に搬送されるよう構成したことを特徴とする。
【００１１】
請求項６によるプッシャー式トンネル炉は、請求項５において、プッシャーの推力がサヤの両端の円筒状突起に加えられるよう構成したことを特徴とする。
【００１３】
請求項７によるサヤは、請求項５または６記載のプッシャー式トンネル炉で用いるサヤであり、サヤの両端に設けた前記円筒状突起の径がサヤの中空円筒形状の本体の径の１／２〜１／３であることを特徴とする。
【００１４】
【発明の実施の形態】
まず、本発明の第１の実施形態として、請求項１に記載されるプッシャー式トンネル炉、請求項２〜３に記載されるプッシャー式トンネル炉で用いる台板および請求項４に記載されるプッシャー式トンネル炉で用いるサヤについて説明する。
【００１５】
図１に示すように、炉体Ｆ内に多数の発熱体１５を配設し、炉体Ｆの前後に入り口作業台（ローダ）１２および出口作業台（アンローダ）１７を設置し、被処理物を装填したサヤを順次炉内に押し込み、炉内を搬送させるためのプッシャー１３を備えたプッシャー式トンネル炉を前提とする。１６は炉内の排ガスを排出するための煙突である。
【００１６】
この実施形態においては、上記プッシャー式トンネル炉において、サヤとして、図２に示すような中空円筒形状のサヤ４を用いる。サヤ４は、アルミナ質、ムライト質、炭化珪素質などのセラミック材料を中空円筒形状に成形、焼成した緻密質の材質からなり、一端部または両端部に同じくセラミック材料からなる取り外し可能な円板状の蓋５を設け、蓋５の中心に設けた孔にセラミック製ボルト６を通し、セラミック製のワッシャー７、ナット８を介して蓋５を固定する。蓋５とサヤ本体との密着面には、セラミック繊維からなるソフトパッキング（ガスケット）９を介在させ、サヤ４各部の熱膨張に起因するズレや応力が吸収されるようにしておくことが望ましい。なお、サヤ４の真円度は０．１ｍｍ以内が望ましい。
【００１７】
サヤ４の蓋５を外してサヤ４の内部に熱処理すべき被処理物を装入し、蓋５を取り付け、図１に示すように、被処理物を装入した中空円筒形状のサヤ４を、プッシャー１３により押し込んで、その中心軸Ｘ−Ｘ（図２）が搬送方向と垂直となるよう炉床１４に載置されるようにし、プッシャーの推力が中空円筒形状のサヤ４の側面に伝達するようにして、サヤ４を炉床１４上で回動させながら炉の入口から出口まで搬送する。サヤ４内部に装入された被処理物はサヤ４内で回転転動を与えられながら均一に加熱され焼成処理される。本発明の方式によれば、サヤ４内に装入する被処理物の実効的な充填層厚を大きく取ることができるから、比較的短い炉長で足り、エネルギー利用効率も改善される。
【００１８】
好ましい実施態様としては、炉床１４に台板を連続的に並置し、並置された台板列に形成されている多数の開口部内にそれぞれ前記中空円筒形状のサヤ４が載置され、台板がプッシャーの推力により搬送されると同時に、中空円筒形状のサヤが前記開口部内で回動しながら台板と共に搬送されるよう構成する。
【００１９】
図３に例示するように、台板１は、サヤ４と同様、セラミック材料を成形、焼成することにより作製され、中央部に中空円筒形状のサヤ４を載置するための長方形状の開口部２を設けた枠体３からなる。開口部２内へのサヤ４（図３に一点鎖線で示す）の載置は、図３に示すように、中空円筒形状のサヤ４の中心軸Ｘ−Ｘが、台板１を炉床１４に連続的に並置しプッシャーにより搬送される場合に、台板１の炉内搬送方向に垂直な辺３ａと平行になるよう載置される。
【００２０】
台板１の開口部２を構成する辺のうち、台板１の炉内搬送方向に垂直な辺３ａの長さＬ_3aはサヤ４の軸方向の長さより長く、台板１の炉内搬送方向に平行な辺３ｂの長さＬ_3bは下記の式で表されるＤより大きい長さに形成されることが好ましい。
Ｄ＝２（２ＲＨ−Ｈ²）^1/2（但し、Ｒ：中空円筒形状のサヤの半径、Ｈ：台板の厚さ）
【００２１】
台板１の開口部２と中空円筒形状のサヤ４の寸法関係を上記のようにすることにより、平坦な炉床１４上に台板１を置き、その開口部２内にサヤを載置したとき、サヤ４の下面が炉床１４に触れずに浮き上がることがなく、プッシャー１３による送りに対しても滑らかに回動することができる。サヤ４と台板１との間の空隙が広過ぎると、サヤ４の安定した回動、移動（搬送）が得られなくなるから、この空隙の大きさは、サヤの円筒軸方向については３〜６ｍｍ程度、サヤの転動方向については２〜５ｍｍ程度とするのが好ましい。
【００２２】
台板１の厚さＨ（図３）については、小さ過ぎるとサヤ４の回動が円滑に行われなくなり、大き過ぎると台板１の重量が増加して熱処理の際の無駄なエネルギー消費が大きくなる。これらのことを考慮して、台板１の厚さＨはサヤ４の直径の２５〜４０％程度とするのが好ましい。
【００２３】
図１に示すように、上記の台板１を、炉床１４上に連続的に並置し、各台板１の開口部２内にそれぞれ中空円筒形状のサヤ４を載置して、プッシャー１３により台板１を押し込み、搬送させると、台板１の枠３の一辺３ａがサヤ４の円筒側面を常時押すこととなり、サヤ４は台板１の枠体３により搬送方向から外れないよう導かれ、サヤ４はその重量とサヤ４の円筒側面と炉床１４との摩擦力によって、炉床上を滑ることなく開口部２内で回動しながら台板と共に搬送される。
【００２４】
中空円筒形状のサヤ４が炉床上を滑ることなく開口部２内で回動するために、炉床１４の平滑度は重要である。炉床は、通常のプッシャー式トンネル炉の場合と同様に、アルミナ質、ムライト質、炭化珪素質などのセラミック材料を成形、焼成した緻密質のものから構成されるが、その平滑度は、炉床有効幅３００ｍｍに対して０．５ｍｍ以下が好ましい。平滑度が不十分な場合には、サヤの回動が円滑でなくなり、あるいは、サヤが回動せずに滑ったり、回転運動に対する摩擦抵抗が過大となって搬送が不安定となり、場合によってはサヤが開口部から飛び出すなどのトラブルも生じる。
【００２５】
サヤ４の回動が円滑に行われ、サヤ４の回動に伴う被処理物の転動攪拌を十分に行い均一な熱処理を達成するためには、中空円筒形状のサヤ４への被処理物の充填率も重要である。サヤ４への被処理物の充填率は、被処理物の形状・性状（粉体、粒体、成形品など）、物性値（安息角、粒度、粒子比重、嵩比重など）によって異なるが、容積比率で５〜４０％が好ましく、１０〜３０％とするのがさらに好ましい。サヤ４への充填深さ（サヤの最下部から被処理物の最上面までの距離）は、サヤの円筒部の半径の１０〜４２％が好ましく、１５〜３４％とするのがさらに好ましい。
【００２６】
台板としては、図３に示すような中央部に開口部２を有する枠体３からなるものに限らず、図４に示すように、この枠体３からなる台板１における台板の炉内搬送方向に垂直な枠３ａの一方を欠いたコ字枠３Ａからなる台板１Ａを使用することもできる。この台板１Ａを、開口部２Ａが同一方向に向くよう炉床上に連続して並置すると、並置された台板２Ａ列にそれぞれ独立した開口部が形成されるから、これらの開口部内に中空円筒形状のサヤ４を載置して、図３の台板１を使用する場合と同様にプッシャーにより搬送する。
【００２７】
台板１Ａを上記のように炉床上に連続して並置することにより形成される開口部の寸法、台板１Ａの厚さＨは、図１に示す枠体３からなる台板１と同一の条件により決定される。
【００２８】
図５は、中空円筒形状のサヤの他の形態を示すものであり、このサヤ４Ａにおいては、円板状の蓋５をセラミックソフトパッキング９を介して両端部に取り付け、蓋５の中心部に設けたボルト挿通孔１０を介して、図２に示すサヤ４の場合と同様にボルト、ナットにより固定するようにしたものである。図６に示す中空円筒形状のサヤ４Ｂは、図５のサヤにおいて、一端部のみに蓋５を着脱可能に設け、他端部を閉塞したものである。これらのサヤ１Ａ、１Ｂもセラミック材料を成形、焼成することにより作製される。
【００２９】
図５〜６に示すサヤ４Ａ、４Ｂにおいて、１１は、サヤの内壁にサヤの中心軸と平行に設けられた突条（堰）であり、突条１１の形成により、被処理物がサヤ内において万遍なく且つ円滑に攪拌され、サヤ内部への付着も防止される。なお、サヤの内部雰囲気、圧力を、炉内雰囲気と同等に保つ必要のある場合には、サヤ４、４Ａ、４Ｂにおいて、例えば円板状の蓋５の中心部近傍などに、内部に装入された被処理物がこぼれない程度の開口部を穿設しておけばよい。
【００３０】
上記本発明の第１の実施形態においては、被処理物を装填したサヤが炉内を回転しながら搬送されるため、被処理物は転動、攪拌を受けながら炉内を通過するので、均一且つ効率のよい加熱が行われるが、炉内を通過する間のサヤの積算回転数が、（炉全長）／｛２×（円周率）×（サヤの円筒部本体の半径）｝で一義的に決まり、任意に回転数を多くすことができないため、サヤ内に装填された被処理物の攪拌が十分でなくなるという問題が生じることがある。
【００３１】
この点を改善し、サヤの転動速度を高め、炉内でのサヤの積算回転数を大きくすることにより、被処理物に対してさらに均一且つ効果的な加熱を行うことを可能とする第２の実施形態が、請求項５〜６に記載されるプッシャー式トンネル炉および請求項７に記載されるプッシャー式トンネル炉で用いるサヤである。以下、本発明の第２の実施形態について説明する。なお、第２の実施形態において、第１の実施形態のものと同一の部材には同じ符号を付した。
【００３２】
第２の実施形態においては、サヤとして中空円筒形状の本体の両端に円筒状突起をそなえたサヤを用い、該サヤの搬送方向にサヤの両端の円筒状突起を支受するための平行なレールを炉内に配設し、被処理物を装入したサヤがその中心軸が搬送方向と垂直となるよう両端の円筒状突起をレール上に載置して、サヤが炉床に接触しないよう保持されるようにし、サヤがプッシャーの推力により回動しながら搬送されるよう構成したことを特徴とする。
【００３３】
すなわち、図９に示すような蓋５を有する中空円筒形状の本体の両端に円筒状突起１９を設けたサヤ２０を用い、図７〜８に示すように、被処理物を装入したサヤ２０の中空円筒形状の本体の両端の円筒状突起１９を支受するための２本の平行なレール１８を炉長方向に配設し、円筒状突起１９の側面がレール１８上を転動できるようにして、円筒状突起１９の転動を介してサヤ２０の中空円筒形状の本体を回転させるよう構成する。
【００３４】
円筒状突起１９の径は、サヤ２０の中空円筒形状の本体の径よりかなり小さく採ることができるから、円筒状突起１９の１回の転動当たりのサヤ２０の搬送方向進行距離は小さくなり、炉内通過中のサヤ２０の転動数は、第１の実施形態に比べて、（サヤの中空円筒形状の本体の半径）／（円筒状突起１９の半径）の割合だけ大きくなり、攪拌効果がより増大し、より均一が熱処理効果が得られる。
【００３５】
円筒状突起１９の径は、サヤ２０の中空円筒形状の本体の径の１／２〜１／３程度に設定するのが好ましく、円筒状突起１９の径が大き過ぎるとサヤの中空円筒形状の本体の転動効果が小さく、円筒状突起１９の径が小さ過ぎると転動が困難となる。
【００３６】
レール１８上での円筒状突起１９の円滑な転動を得るため、レールの表面の平滑度、平坦度、および円筒状突起１９の表面の平滑度、真円度は重要である。レールの平坦度は搬送方向に対して３００ｍｍ当たり０．５ｍｍ以下、円筒状突起の真円度は０．１ｍｍ以内が望ましい。
【００３７】
レールについては、とくに耐摩耗性が要求されるため、高緻密質の高アルミナ質あるいは炭化珪素質のもので構成するのが好ましく、レール１８上を転動するサヤ２０の円筒状突起１９の材質もこれに準じる耐摩耗特性をそなえたものであることが望ましい。
【００３８】
２本の平行なレール１８の間隔は、図７に示すように、サヤ２０の中空円筒形状の本体の長さより若干大きくし、サヤ２０の中空円筒形状の本体が炉床１４に接触しないよう保持されるようにし、プッシャー１３の推力がサヤ２０の両端の円筒状突起１９に加えられるよう構成して、サヤ２０がプッシャー１３の推力により回動しながら搬送されるようにする。この場合、レール１８に、炉入口から炉出口に向け僅かな下り勾配を設けると、プッシャーの推力により、より円滑な転動が達成できる。
【００３９】
好ましい実施態様として、図７〜８に示すように、レール１８上に台板１Ｂ（１Ｃ）を連続的に並置し、並置された台板列に形成されている多数の開口部２Ｂ（２Ｃ）内に、それぞれサヤ２０の円筒状突起１９がレール１８上に載置され、サヤ２０の中空円筒形状の本体が炉床に接触せず懸垂状態に保持されるよう嵌め込まれ、台板１がプッシャー１３の推力により搬送されると同時に、サヤ２０の円筒状突起１９がレール１８上を転動するとともに、サヤ２０が開口部２Ｂ（２Ｃ）内で回動しながら台板１と共に搬送されるよう構成される。
【００４０】
具体的には、図１０に示すように、台板１Ｂとして、サヤ２０の中空円筒形状の本体を嵌め込むための長方形状の開口部２Ｂ₁に連続して、両端の円筒状突起１９を嵌め込むための開口部２Ｂ₂を有する枠体からなるものを使用する。台板１Ｂは、サヤ２０と同様、セラミック材料を成形、焼成することにより作製される。開口部２Ｂ内へのサヤ２０の配置（図１１において２点鎖線で示す）は、図１１に示すように、サヤ２０の中空円筒形状の本体の中心軸Ｘ−Ｘが、台板１Ｂをレール１８に連続的に並置しプッシャーにより搬送される場合に、台板１Ｂの炉内搬送方向に垂直な辺３ａと平行になるよう配置される。
【００４１】
台板１Ｂがプッシャー１３の推力により搬送される際、台板１の開口部２Ｂ₂の縁部でサヤ２０の円筒状突起１９を押すことができるよう、円筒状突起１９と開口部２Ｂ₂との間隙が開き過ぎないよう、開口部２Ｂ₂の寸法ｌ₁は適正に規定することが必要である。開口部２はサヤ２０の中空円筒形状の本体に触れないよう、寸法Ｌ_3bは中空円筒形状の本体の径より大きく、Ｌ_3aは中空円筒形状の本体の長さより大きくし、また、開口部２Ｂ₂のｌ₂は円筒状突起１９の長さより大きくすることが必要である。
【００４２】
台板１Ｂの開口部２Ｂとサヤ２０の寸法関係を上記のようにすることにより、図８、図１１に示すように、台板１Ｂは、レール１８上に載置した台板１の開口部２Ｂにサヤ２０の円筒状突起１９が僅かな空隙をもって嵌まり込んだ状態でレール１８上に載り、サヤ２０の中空円筒形状の本体は、開口部２Ｂ₁に台板１Ｂ、レール側面および炉床１４に接触することなく嵌まり込んで、懸垂状態に保持される。
【００４３】
プッシャー１３の推力により台板１Ｂが炉内を搬送されると、台板１Ｂの開口部２Ｂ₂の縁部のうち、搬送方向に対して後方の縁部が円筒状突起１９を前方に押すため、円筒状突起１９はレール１８上を滑ることなく転動し、その結果サヤ２０全体が転動して、内部に装填された被処理物を転動、攪拌しながら台板１Ｂと共に前方へ移動する。安定した転動を継続するために、サヤ２０の円筒状突起１９と台板１Ｂの開口部２Ｂ₂との間隙は２〜５ｍｍとするのが好ましい。
【００４４】
レール１８に対して、搬送方向に若干の下り勾配を形成する場合、勾配が大き過ぎるとサヤ２０が台板１Ｂの開口部から縁部を乗り越えて勝手に転動してしまうため、プッシャーの推力を受けていない時は摩擦力で静止しており、推力を受けた時は容易に転動を開始するような勾配とするのがよく、勾配の角度は、例えば０．２〜１．５°、さらに望ましくは０．４〜０．８°とする。
【００４５】
台板としては、図１０に示すような、中央部に開口部２Ｂを有する枠体３Ｂからなるものに限らず、図１２に示すように、この枠体３Ｂからなる台板１Ｂにおける台板の炉内搬送方向に垂直な枠３ａの一方を欠いたコ字枠３Ｃからなる台板１Ｃを使用することもできる。この台板１Ｃを、開口部２Ｃ（２Ｃ₁＋２Ｃ₂）が同一方向に向くよう炉床上に連続して並置すると、並置された台板２Ｃ列にそれぞれ独立した開口部が形成されるから、これらの開口部内にサヤ２０を嵌め込み、図１０の台板１Ｂを使用する場合と同様の態様でプッシャーにより搬送することができる。
【００４６】
台板１Ｂ、１Ｃを使用する場合のサヤ２０への被処理物の充填については、第１の実施形態の場合と同様であり、被処理物の形状、性状、物性値を勘案して調整されるが、容積比率充填率で５〜４０％が好ましく、１０〜３０％とするのがさらに好ましい。サヤ２０への被処理物の充填深さは、サヤの中空円筒形状の本体の半径の１０〜４２％、さらに好ましくは１５〜３４％とする。
【００４７】
図１３は、サヤ２０各部の構成部品と組立状態の１実施態様を示すものであり、このサヤ２０Ａにおいては、中空円筒形状の本体に円板状の蓋５をセラミックソフトパッキング９を介して両端部に取り付け、蓋５の中心部に設けたボルト挿通孔からボルト６を突出させて、ワッシャー７とナット８で固定し、両端に円筒状突起１９を、ネジ孔２１を介してボルト６に嵌め込み、固定するようにしたものである。蓋５は、第１の実施形態で使用するサヤ４と同様、一方が本体と一体化しており、他方のみが取り外し自在となっている構造でもよい。
【００４８】
このサヤ２０Ａもセラミック材料を成形、焼成することにより作製される。なお、サヤの内壁に、図５〜６に示すように、サヤの中心軸と平行な突条（堰）設けてもよく、突条の形成により、被処理物がサヤ内において万遍なく且つ円滑に攪拌され、サヤ内部への付着も防止される。また、サヤの内部雰囲気、圧力を、炉内雰囲気と同等に保つ必要のある場合には、蓋５に内部に装入された被処理物がこぼれない程度の開口部を穿設しておけばよい。
【００４９】
【実施例】
以下、本発明の実施例について説明し、その効果を実証する。
実施例１
図１に示すプッシャー式トンネル炉の炉床に、図３に示すような厚さ２５ｍｍの台板を連続的に並置した。図２に示すような中空円筒形状のサヤ（円筒部外径１２５ｍｍ）の内部にチタン酸バリウムを主成分とするセラミック粉体を装入し、このサヤを台板の開口部に載置して、プッシャーにより搬送し、熱処理を行った。
【００５０】
台板は、アルミナ質約８０％、サヤはアルミナ質約６０％の、いずれも通常よく用いられるアルミナ−シリカ系の材料より成形した。台板の枠体の枠３ａの長さＬ_3aは、サヤの軸方向長さより４ｍｍ長くし、枠３ｂの長さＬ_3bはＤ（１５０ｍｍ）より２ｍｍ長くした。また、セラミック粉末のサヤ内への充填率は容積比率充填率で約２９％、充填深さはサヤ半径の３３％とした。
【００５１】
熱処理の結果、被処理物のチタン酸バリウム系セラミック粉末は、均一に加熱、焼成された。しかも、通常の平型サヤ３段積みの場合と比べて処理量が増え、消費電力が少なくて済んだ。これを従来の処理能力と同一換算して比較すると、炉長の約３０％短縮、エネルギーの約１５％節約と同等であるという結果が得られた。
【００５２】
実施例２
図７に示すプッシャー式トンネル炉において、傾斜角度０．６°のレールを平行に配置し、図１０に示すような厚さ２５ｍｍの台板を連続的に並置した。図９に示すような円筒状突起付きのサヤ（中空円筒形状の本体の外径１２５ｍｍ、長さ１５０ｍｍ、円筒状突起外径６０ｍｍ）の内部にチタン酸バリウムを主成分とするセラミック粉体を装入し、このサヤを台板の開口部に配置して、プッシャーにより搬送し、サヤを転動させながら炉内を通過させ、熱処理を行った。
【００５３】
レールはアルミナ９２％以上の高アルミナ質の材料から成形し、台板は、アルミナ質約８０％、サヤはアルミナ質約６０％の、いずれも通常よく用いられるアルミナ−シリカ系の材料より成形した。また、セラミック粉末のサヤ内への充填率は容積比率充填率で約２９％、充填深さはサヤ半径の３３％とした。
【００５４】
熱処理の結果、回収された被処理物のチタン酸バリウム系セラミック粉末は、実施例１のものより、さらに均一に加熱、焼成しているのが認められた。通常の平型サヤ３段積みの場合と比べての処理量の増加および消費電力の節約は実施例１の場合と同等以上であった。
【００５５】
【発明の効果】
本発明によれば、被処理物を装入した中空円筒形状のサヤが台板の搬送と共に、回動しながら炉内を移動し、その結果、被処理物は転動、攪拌を受けながら炉内を通過するので、均一且つ効率のよい加熱が行われ、平型のサヤに被処理物を薄く充填し、これらのサヤを台板に載置して搬送する従来方式に比べて、実効的な充填層厚を大きくとることができるため、炉長を短くして効率的な熱処理を行うことが可能となり、エネルギー利用効率も改善される。
【００５６】
請求項５〜６に記載のプッシャー式トンネル炉によれば、サヤの転動速度が高められ、炉内でのサヤの積算回転数を大きくすることにより、被処理物に対してさらに均一且つ効果的な加熱を行うことが可能となるから、さらに効率的な熱処理を行うことができる。
【図面の簡単な説明】
【図１】本発明を適用するプッシャー式トンネル炉の一実施例の全体概念図である。
【図２】図１のプッシャー式トンネル炉で使用する中空円筒形状のサヤの一実施例を示す斜視図である。
【図３】図１のプッシャー式トンネル炉で使用する台板の一実施例を示す平面、側面図である。
【図４】図１のプッシャー式トンネル炉で使用する台板の他の実施例を示す平面、側面図である。
【図５】図１のプッシャー式トンネル炉で使用する中空円筒形状のサヤの他の実施例を示す分解斜視図である。
【図６】図１のプッシャー式トンネル炉で使用する中空円筒形状のサヤのさらに他の実施例を示す分解斜視図である。
【図７】本発明を適用するプッシャー式トンネル炉の他の実施例の全体概念図である。
【図８】図７の一部断面図である。
【図９】図７のプッシャー式トンネル炉で使用する円筒状突起付きサヤの実施例を示す斜視図である。
【図１０】図７のプッシャー式トンネル炉で使用する台板の一実施例を示す平面、側面図である。
【図１１】図１０の台板にサヤを配置した状態を示す平面、側面図である。
【図１２】図７のプッシャー式トンネル炉で使用する台板の他の実施例を示す平面、側面図である。
【図１３】図７のプッシャー式トンネル炉で使用する円筒状突起付きサヤの他の実施例を示す分解斜視図である。
【符号の説明】
１台板
1A 台板
1B 台板
1C 台板
２開口部
2A 開口部
2B 開口部
2C 開口部
2B₁開口部
2B₂開口部
2C₁開口部
2C₂開口部
３枠体
3B 枠体
3C 枠体
3a 枠
3b 枠
４サヤ
4A サヤ
4B サヤ
５蓋
６ボルト
７ワッシャー
８ナット
９パッキング
10 ボルト孔
11 突条
12 入り口作業台
13 プッシャー
14 炉床
15 発熱体
16 煙突
17 出口作業台
18 レール
19 円筒状突起
20 サヤ
20A サヤ
21 ネジ孔
22 測温体
Ｆ炉本体[0001]
BACKGROUND OF THE INVENTION
In the present invention, ceramic powder, granules, small molded products, chips including ceramic materials are loaded on a jig such as a sheath, pushed into a heating furnace by a pusher, conveyed, and fired. Or it is related with the improvement of the pusher-type tunnel furnace for performing a sintering process, and the baseplate and sheath used with the said tunnel furnace.
[0002]
[Prior art]
Conventionally, when the above-mentioned processed products are heat-treated at a high temperature of 1000 ° C. or higher for firing and sintering, generally, for example, the processed products are loaded into a square or circular sheath with a thickness of 10 to 20 mm. These sheaths are stacked on a base plate in two or three stages, are pushed continuously into a tunnel furnace with a pusher and conveyed through the furnace, and a heat treatment is performed over a sufficient time.
[0003]
However, with this method, in order to uniformly heat the product to be processed, the filling thickness of the product to be processed must be reduced, so a longer furnace length is generally required for the required processing capacity. For this reason, there is a problem that it is not economical from the viewpoint of the equipment cost, and further, the weight of the firing jig such as the sheath and the setter is increased in proportion to the furnace length, and wasteful energy is consumed accordingly. .
[0004]
[Problems to be solved by the invention]
The present invention was made as a result of reexamination of the structure of the sheath and the base plate in order to eliminate the above-mentioned conventional problems in the pusher-type tunnel furnace, and its purpose is in particular at 1000 ° C. or higher. Ceramic powders, granules, small molded products, chips containing ceramic materials, etc. can be uniformly heat-treated in a relatively short furnace length at high temperatures, and firing with high energy utilization efficiency is possible. It is an object of the present invention to provide a pusher type tunnel furnace and a base plate and a sheath used in the pusher type tunnel furnace.
[0005]
[Means for Solving the Problems]
To achieve the above objectives Claim 1 The pusher-type tunnel furnace with the pusher-type tunnel furnace equipped with a pusher for sequentially pushing the sheath loaded with the workpiece into the furnace and transporting the inside of the furnace uses a hollow cylindrical sheath as the sheath. The base plates having openings in the hearth are continuously juxtaposed, and each of the openings in the juxtaposition of the base plate rows juxtaposed. A hollow cylindrical sheath is placed on the hearth so that its central axis is perpendicular to the conveying direction. The base plate Due to the thrust of the pusher At the same time as being conveyed, a hollow cylindrical sheath is formed in the opening. While rotating With base plate It is configured to be conveyed.
[0007]
Claim 2 Pusher type tunnel furnace Used in The base plate A base plate used in the pusher-type tunnel furnace according to claim 1, It is a base plate made of a frame provided with a rectangular opening for placing a hollow cylindrical sheath at the center, and among the sides constituting the opening, the base plate in the in-furnace transport direction The vertical side is longer than the axial length of the sheath, and the side parallel to the in-furnace conveying direction of the base plate is formed to have a length larger than D represented by the following formula.
D = 2 (2RH-H ² ) ^1/2 (However, R: radius of the hollow cylindrical sheath, H: thickness of the base plate)
[0008]
Claim 3 Pusher type tunnel furnace Used in The base plate In claim 2, The base plate made of the frame body is formed in a U-shaped frame shape lacking one of the frames perpendicular to the conveying direction of the base plate in the furnace.
[0009]
Claim 4 Pusher type tunnel furnace Used in Saya A shear used in the pusher-type tunnel furnace according to claim 1, wherein the hollow cylindrical shape is used. Saya In The cylindrical inner wall surface is provided with a plurality of protrusions parallel to the axial direction of the cylinder, and at least one of the end portions of the cylinder is configured to be openable for loading and discharging the workpiece. To do.
[0010]
Claim 5 The pusher-type tunnel furnace is a pusher-type tunnel furnace equipped with a pusher for sequentially pushing the workpiece loaded with the workpiece into the furnace and transporting the inside of the furnace. Using a sheath with protrusions, parallel rails for supporting cylindrical protrusions at both ends of the sheath in the conveying direction of the sheath are arranged in the furnace. Base plates having openings on the hearth are continuously juxtaposed, and the hollow cylindrical sheaths are respectively placed in a large number of openings of the juxtaposed base plate rows so that the central axis thereof is perpendicular to the transport direction. And Saya ’s Cylindrical protrusions at both ends are placed on the rail so that the sheath does not touch the hearth, At the same time as the base plate is transported by the thrust of the pusher, the hollow cylindrical sheath rotates with the base plate while rotating in the opening. It is configured to be conveyed.
[0011]
Claim 6 The pusher tunnel furnace according to claim 5 The pusher thrust is applied to the cylindrical protrusions at both ends of the sheath.
[0013]
Claim 7 By Saya claims 5 or 6 description The cylindrical projection provided at both ends of the sheath Diameter Is the diameter of the hollow cylindrical body of Saya 1/2 to 1/3 of It is characterized by being.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
First, as 1st Embodiment of this invention, a claim 1 Pusher type tunnel furnace as described in claim 2-3 Pusher type tunnel furnace as described in Used in Base plate and claims 4 Pusher type tunnel furnace as described in Used in Saya will be explained.
[0015]
As shown in FIG. 1, a large number of heating elements 15 are arranged in a furnace body F, and an entrance work table (loader) 12 and an exit work table (unloader) 17 are installed before and after the furnace body F, A pusher-type tunnel furnace equipped with a pusher 13 for sequentially pushing the sheath loaded with slag into the furnace and transporting the inside of the furnace is assumed. Reference numeral 16 denotes a chimney for discharging the exhaust gas in the furnace.
[0016]
In this embodiment, a hollow cylindrical sheath 4 as shown in FIG. 2 is used as the sheath in the pusher type tunnel furnace. The sheath 4 is made of a dense material obtained by molding and firing a ceramic material such as alumina, mullite, or silicon carbide into a hollow cylindrical shape, and is a removable disk shape that is also made of a ceramic material at one or both ends. And a ceramic bolt 6 is passed through a hole provided in the center of the lid 5, and the lid 5 is fixed via a ceramic washer 7 and a nut 8. It is desirable to interpose a soft packing (gasket) 9 made of ceramic fibers on the close contact surface between the lid 5 and the sheath body so as to absorb the displacement and stress caused by the thermal expansion of each part of the sheath 4. The roundness of the sheath 4 is preferably within 0.1 mm.
[0017]
The cover 5 of the sheath 4 is removed, the workpiece to be heat-treated is inserted into the sheath 4, the lid 5 is attached, and the hollow cylindrical sheath 4 with the workpiece is loaded as shown in FIG. Then, it is pushed by the pusher 13 so that the central axis XX (FIG. 2) is placed on the hearth 14 so as to be perpendicular to the conveying direction, and the thrust of the pusher is transmitted to the side surface of the hollow cylindrical shaped sheath 4. In this way, the sheath 4 is conveyed from the furnace inlet to the outlet while being rotated on the hearth 14. The object to be processed inserted into the sheath 4 is uniformly heated and fired while being rotationally rolled in the sheath 4. According to the method of the present invention, since the effective packed layer thickness of the workpiece to be charged in the sheath 4 can be increased, a relatively short furnace length is sufficient, and energy utilization efficiency is improved.
[0018]
As a preferred embodiment, the base plate is continuously juxtaposed on the hearth 14, and the hollow cylindrical sheath 4 is placed in each of a plurality of openings formed in the juxtaposed base plate row, and the base plate Is conveyed by the thrust of the pusher, and at the same time, the hollow cylindrical sheath is conveyed along with the base plate while rotating in the opening.
[0019]
As illustrated in FIG. 3, the base plate 1 is produced by molding and firing a ceramic material, like the sheath 4, and a rectangular opening for placing the hollow cylindrical sheath 4 in the center. The frame 3 is provided with 2. As shown in FIG. 3, the mounting of the sheath 4 (indicated by a one-dot chain line in FIG. 3) into the opening 2 is such that the central axis XX of the hollow cylindrical sheath 4 ties the base plate 1 to the hearth 14. Are placed so as to be parallel to the side 3a perpendicular to the in-furnace transport direction of the base plate 1.
[0020]
Of the sides constituting the opening 2 of the base plate 1, the length L of the side 3a perpendicular to the in-furnace transport direction of the base plate 1 _3a Is longer than the axial length of the sheath 4 and the length L of the side 3b parallel to the in-furnace conveying direction of the base plate 1 _3b Is preferably formed to have a length larger than D represented by the following formula.
D = 2 (2RH-H ² ) ^1/2 (However, R: radius of the hollow cylindrical sheath, H: thickness of the base plate)
[0021]
By making the dimensional relationship between the opening 2 of the base plate 1 and the hollow cylindrical sheath 4 as described above, the base plate 1 is placed on the flat hearth 14 and the sheath is placed in the opening 2. At this time, the lower surface of the sheath 4 does not float without touching the hearth 14, and can smoothly rotate with respect to the feed by the pusher 13. If the gap between the sheath 4 and the base plate 1 is too wide, stable rotation and movement (conveyance) of the sheath 4 cannot be obtained. Therefore, the size of the gap is 3 to 3 in the cylindrical axis direction of the sheath. About 6 mm, the rolling direction of the sheath is preferably about 2 to 5 mm.
[0022]
If the thickness H (FIG. 3) of the base plate 1 is too small, the sheath 4 cannot be rotated smoothly. If it is too large, the weight of the base plate 1 increases and wasteful energy consumption occurs during heat treatment. growing. Considering these, the thickness H of the base plate 1 is preferably about 25 to 40% of the diameter of the sheath 4.
[0023]
As shown in FIG. 1, the base plates 1 are continuously juxtaposed on the hearth 14, and hollow cylindrical shaped sheaths 4 are placed in the openings 2 of the base plates 1, respectively. When the base plate 1 is pushed in and conveyed, one side 3a of the frame 3 of the base plate 1 always presses the cylindrical side surface of the sheath 4, and the sheath 4 is guided by the frame body 3 of the base plate 1 so as not to deviate from the transport direction. The sheath 4 is conveyed along with the base plate while rotating within the opening 2 without sliding on the hearth by the weight and the frictional force between the cylindrical side surface of the sheath 4 and the hearth 14.
[0024]
The smoothness of the hearth 14 is important because the hollow cylindrical sheath 4 rotates within the opening 2 without sliding on the hearth. The hearth is composed of a dense material obtained by molding and firing a ceramic material such as alumina, mullite, or silicon carbide, as in the case of a normal pusher type tunnel furnace. 0.5 mm or less is preferable with respect to an effective floor width of 300 mm. If the smoothness is insufficient, the sheath will not rotate smoothly, or the sheath will slip without rotating, or the frictional resistance against rotational motion will be excessive, making the conveyance unstable. Troubles such as Saya jumping out of the opening also occur.
[0025]
In order to smoothly rotate the sheath 4 and sufficiently perform rolling and stirring of the object to be processed along with the rotation of the sheath 4 to achieve uniform heat treatment, the object to be processed on the hollow cylindrical shape of the sheath 4 is described. The filling rate is also important. The filling rate of the material to be treated into the sheath 4 varies depending on the shape and properties of the material to be treated (powder, granules, molded products, etc.) and physical properties (such as repose angle, particle size, particle specific gravity, bulk specific gravity, etc.) The volume ratio is preferably 5 to 40%, and more preferably 10 to 30%. The filling depth into the sheath 4 (distance from the lowest portion of the sheath to the uppermost surface of the workpiece) is preferably 10 to 42% of the radius of the cylindrical portion of the sheath, and more preferably 15 to 34%.
[0026]
The base plate is not limited to the one having the frame 3 having the opening 2 at the center as shown in FIG. 3, and as shown in FIG. 4, the base plate furnace in the base plate 1 having the frame 3 A base plate 1A composed of a U-shaped frame 3A lacking one of the frames 3a perpendicular to the inner conveyance direction can also be used. When this base plate 1A is continuously juxtaposed on the hearth so that the openings 2A face in the same direction, independent openings are formed in the juxtaposed base plate 2A rows, so that hollow cylinders are formed in these openings. The shaped sheath 4 is placed and conveyed by a pusher in the same manner as when the base plate 1 of FIG. 3 is used.
[0027]
The size of the opening formed by juxtaposing the base plate 1A continuously on the hearth as described above, and the thickness H of the base plate 1A are the same as those of the base plate 1 made of the frame 3 shown in FIG. Determined by conditions.
[0028]
FIG. 5 shows another embodiment of a hollow cylindrical sheath. In this sheath 4A, disk-shaped lids 5 are attached to both ends via ceramic soft packing 9 and are attached to the center of lid 5. As in the case of the sheath 4 shown in FIG. 2, the bolts and nuts are used to fix the bolts through the provided bolt insertion holes 10. The hollow cylindrical sheath 4B shown in FIG. 6 is the same as the sheath of FIG. 5 except that the lid 5 is detachably provided only at one end and the other end is closed. These sheaths 1A and 1B are also produced by forming and firing a ceramic material.
[0029]
In the sheaths 4 </ b> A and 4 </ b> B shown in FIGS. 5 to 6, reference numeral 11 is a protrusion (weir) provided on the inner wall of the sheath in parallel with the central axis of the sheath. In this case, the agitation is performed uniformly and smoothly, and adhesion to the inside of the sheath is also prevented. If it is necessary to keep the inner atmosphere and pressure of the sheath at the same level as the atmosphere in the furnace, the sheath is inserted into the sheath 4, 4A, 4B, for example, in the vicinity of the center of the disc-shaped lid 5, etc. What is necessary is just to pierce the opening part to such an extent that the to-be-processed object spilled out.
[0030]
In the first embodiment of the present invention, since the sheath loaded with the object to be processed is conveyed while rotating in the furnace, the object to be processed passes through the furnace while being rolled and stirred. Although efficient heating is performed, the total number of rotations of the sheath while passing through the furnace is uniquely defined by (furnace total length) / {2 × (circumference ratio) × (radius of the cylindrical portion body of the sheath)}. Since the rotational speed cannot be increased arbitrarily, there is a problem that the workpiece loaded in the sheath is not sufficiently stirred.
[0031]
By improving this point, increasing the rolling speed of the sheath, and increasing the total number of rotations of the sheath in the furnace, it is possible to more uniformly and effectively heat the workpiece. When A second embodiment to claim 5-6 Pusher-type tunnel furnace and claim 7 Pusher type tunnel furnace as described in Used in Saya. Hereinafter, a second embodiment of the present invention will be described. In the second embodiment, the same members as those in the first embodiment are denoted by the same reference numerals.
[0032]
In the second embodiment, a sheath having cylindrical protrusions at both ends of a hollow cylindrical main body is used as the sheath, and parallel rails for supporting the cylindrical protrusions at both ends of the sheath in the conveying direction of the sheath Is placed in the furnace, and the cylindrical protrusions at both ends are placed on the rail so that the center axis of the sheath with the workpiece is perpendicular to the conveying direction so that the sheath does not contact the hearth It is configured to be held so that the sheath is conveyed while being rotated by the thrust of the pusher.
[0033]
That is, using a sheath 20 provided with cylindrical projections 19 at both ends of a hollow cylindrical main body having a lid 5 as shown in FIG. 9, as shown in FIGS. Two parallel rails 18 for supporting the cylindrical projections 19 at both ends of the hollow cylindrical main body are arranged in the furnace length direction so that the side surfaces of the cylindrical projections 19 can roll on the rails 18. Thus, the hollow cylindrical main body of the sheath 20 is rotated through the rolling of the cylindrical protrusion 19.
[0034]
Since the diameter of the cylindrical protrusion 19 can be made considerably smaller than the diameter of the hollow cylindrical main body of the sheath 20, the traveling distance of the sheath 20 in the conveying direction per one rolling of the cylindrical protrusion 19 is reduced. Compared with the first embodiment, the rolling number of the sheath 20 passing through the furnace is increased by a ratio of (radius of the hollow cylindrical body of the sheath) / (radius of the cylindrical projection 19), and the stirring effect Increases, and a more uniform heat treatment effect is obtained.
[0035]
The diameter of the cylindrical protrusion 19 is preferably set to about ½ to の of the diameter of the hollow cylindrical body of the sheath 20, and if the diameter of the cylindrical protrusion 19 is too large, the hollow cylindrical shape of the sheath If the rolling effect of the main body is small and the diameter of the cylindrical protrusion 19 is too small, the rolling becomes difficult.
[0036]
In order to obtain a smooth rolling of the cylindrical protrusion 19 on the rail 18, the smoothness and flatness of the rail surface and the smoothness and roundness of the surface of the cylindrical protrusion 19 are important. The flatness of the rail is preferably 0.5 mm or less per 300 mm with respect to the conveying direction, and the roundness of the cylindrical protrusion is preferably within 0.1 mm.
[0037]
Since the rail is particularly required to have wear resistance, it is preferable that the rail be made of a high-density, high-alumina or silicon carbide material. The material of the cylindrical projection 19 of the sheath 20 that rolls on the rail 18 is preferable. It is also desirable to have wear resistance characteristics similar to this.
[0038]
As shown in FIG. 7, the distance between the two parallel rails 18 is slightly larger than the length of the hollow cylindrical body of the sheath 20, and the hollow cylindrical body of the sheath 20 is held so as not to contact the hearth 14. In this manner, the thrust of the pusher 13 is applied to the cylindrical projections 19 at both ends of the sheath 20 so that the sheath 20 is conveyed while being rotated by the thrust of the pusher 13. In this case, if the rail 18 is provided with a slight downward gradient from the furnace inlet to the furnace outlet, smoother rolling can be achieved by the thrust of the pusher.
[0039]
As a preferred embodiment, as shown in FIGS. 7 to 8, the base plate 1B (1C) is continuously juxtaposed on the rail 18, and a plurality of openings 2B (2C) formed in the juxtaposed base plate row. The cylindrical projections 19 of the sheaths 20 are respectively placed on the rails 18 so that the hollow cylindrical main body of the sheath 20 is fitted in a suspended state without contacting the hearth, and the base plate 1 is pushed. At the same time, the cylindrical projection 19 of the sheath 20 rolls on the rail 18, and the sheath 20 is transported with the base plate 1 while rotating in the opening 2B (2C). Composed.
[0040]
Specifically, as shown in FIG. 10, a rectangular opening 2B for fitting the hollow cylindrical body of the sheath 20 as the base plate 1B. ₁ 2B for opening the cylindrical protrusions 19 at both ends. ₂ Use a frame having a frame. The base plate 1 </ b> B is produced by molding and firing a ceramic material, like the sheath 20. The arrangement of the sheath 20 in the opening 2B (indicated by a two-dot chain line in FIG. 11) is such that the central axis XX of the hollow cylindrical main body of the sheath 20 rails the base plate 1B as shown in FIG. 18 are arranged so as to be parallel to the side 3a perpendicular to the in-furnace transport direction of the base plate 1B when being continuously juxtaposed to 18 and transported by the pusher.
[0041]
When the base plate 1B is conveyed by the thrust of the pusher 13, the opening 2B of the base plate 1 ₂ So that the cylindrical projection 19 of the sheath 20 can be pushed by the edge of the cylindrical projection 19 and the opening 2B. ₂ 2B so that the gap with ₂ Dimensions l ₁ Must be properly defined. The opening 2 has a dimension L so as not to touch the hollow cylindrical body of the sheath 20. _3b Is larger than the diameter of the hollow cylindrical body, L _3a Is larger than the length of the hollow cylindrical body, and the opening 2B ₂ L ₂ Needs to be larger than the length of the cylindrical protrusion 19.
[0042]
By making the dimensional relationship between the opening 2B of the base plate 1B and the sheath 20 as described above, as shown in FIGS. 8 and 11, the base plate 1B is an opening of the base plate 1 placed on the rail 18. The cylindrical projection 19 of the sheath 20 is fitted on the rail 18 in a state where the cylindrical projection 19 of the sheath 20 is fitted with a slight gap, and the hollow cylindrical body of the sheath 20 has the opening 2B. ₁ The base plate 1B, the rail side surface, and the hearth 14 are fitted into the base plate 1B without being in contact with each other, and are held in a suspended state.
[0043]
When the base plate 1B is transported through the furnace by the thrust of the pusher 13, the opening 2B of the base plate 1B. ₂ Of the edges, the rear edge with respect to the transport direction pushes the cylindrical protrusion 19 forward, so that the cylindrical protrusion 19 rolls without sliding on the rail 18, and as a result, the entire sheath 20 rolls. Then, the workpiece loaded inside is moved forward together with the base plate 1B while rolling and stirring. In order to continue stable rolling, the cylindrical protrusion 19 of the sheath 20 and the opening 2B of the base plate 1B ₂ Is preferably 2 to 5 mm.
[0044]
When a slight downward gradient is formed in the conveyance direction with respect to the rail 18, the shear 20 will roll over the edge from the opening of the base plate 1B if the gradient is too large. When it receives no thrust, it is stationary by frictional force, and when it receives thrust, it is good to make it a gradient that starts rolling easily. The angle of the gradient is, for example, 0.2 to 1.5 ° More desirably, the angle is set to 0.4 to 0.8 °.
[0045]
As shown in FIG. 10, the base plate is not limited to a frame 3B having an opening 2B at the center, but as shown in FIG. 12, the base plate 1B made of the frame 3B A base plate 1C composed of a U-shaped frame 3C lacking one of the frames 3a perpendicular to the in-furnace transport direction can also be used. The base plate 1C is connected to the opening 2C (2C ₁ + 2C ₂ 10) are arranged in parallel on the hearth so that they face in the same direction, so that independent openings are formed in the juxtaposed base plate 2C row, so that the sheath 20 is fitted into these openings, and the base plate of FIG. It can be conveyed by a pusher in the same manner as in the case of using 1B.
[0046]
The filling of the workpiece into the sheath 20 when using the base plates 1B and 1C is the same as in the first embodiment, and is adjusted in consideration of the shape, properties, and physical property values of the workpiece. However, the volume ratio filling ratio is preferably 5 to 40%, and more preferably 10 to 30%. The filling depth of the workpiece into the sheath 20 is 10 to 42%, more preferably 15 to 34% of the radius of the hollow cylindrical body of the sheath.
[0047]
FIG. 13 shows one embodiment of the components of each part of the sheath 20 and the assembled state. In this sheath 20A, the disc-shaped lid 5 is attached to both ends of the hollow cylindrical body via the ceramic soft packing 9. The bolt 6 is protruded from a bolt insertion hole provided in the center of the lid 5 and fixed with a washer 7 and a nut 8. Cylindrical protrusions 19 are fitted into the bolt 6 through screw holes 21 at both ends. It is intended to be fixed. Similarly to the sheath 4 used in the first embodiment, the lid 5 may have a structure in which one side is integrated with the main body and only the other side is removable.
[0048]
The sheath 20A is also produced by molding and firing a ceramic material. In addition, as shown in FIGS. 5 to 6, the inner wall of the sheath may be provided with a ridge (weir) parallel to the central axis of the sheath. By forming the ridge, the object to be processed is uniformly distributed in the sheath. It is stirred smoothly and adhesion to the inside of the sheath is also prevented. In addition, when it is necessary to keep the inner atmosphere and pressure of the sheath equal to the atmosphere in the furnace, the lid 5 should be provided with an opening that does not spill the object to be processed. Good.
[0049]
【Example】
Hereinafter, examples of the present invention will be described and the effects thereof will be demonstrated.
Example 1
A base plate having a thickness of 25 mm as shown in FIG. 3 was continuously juxtaposed on the hearth of the pusher type tunnel furnace shown in FIG. A ceramic powder mainly composed of barium titanate is placed inside a hollow cylindrical sheath (cylindrical outer diameter: 125 mm) as shown in FIG. 2, and this sheath is placed in the opening of the base plate. Then, it was conveyed by a pusher and subjected to heat treatment.
[0050]
The base plate was formed from an alumina-silica-based material, which is generally used, approximately 80% alumina and about 60% alumina. Length L of frame 3a of base plate frame _3a Is 4 mm longer than the axial length of the sheath and the length L of the frame 3b. _3b Was 2 mm longer than D (150 mm). The filling rate of the ceramic powder in the sheath was about 29% in volume ratio filling rate, and the filling depth was 33% of the sheath radius.
[0051]
As a result of the heat treatment, the barium titanate ceramic powder to be treated was uniformly heated and fired. In addition, the processing amount is increased and the power consumption is reduced as compared with the case of a normal flat type three-layer stack. Comparing this with the conventional processing capacity, the result was that the furnace length was shortened by about 30% and the energy was saved by about 15%.
[0052]
Example 2
In the pusher-type tunnel furnace shown in FIG. 7, rails having an inclination angle of 0.6 ° were arranged in parallel, and base plates having a thickness of 25 mm as shown in FIG. 10 were continuously juxtaposed. A ceramic powder mainly composed of barium titanate is placed inside a sheath having a cylindrical projection as shown in FIG. 9 (the outer diameter of the hollow cylindrical body is 125 mm, the length is 150 mm, and the cylindrical projection has an outer diameter of 60 mm). The sheath was placed at the opening of the base plate, conveyed by a pusher, passed through the furnace while rolling the sheath, and heat-treated.
[0053]
The rail was formed from a high alumina material of 92% alumina or more, the base plate was formed from about 80% alumina, and the sheath was formed from a commonly used alumina-silica-based material of about 60% alumina. . The filling rate of the ceramic powder in the sheath was about 29% in volume ratio filling rate, and the filling depth was 33% of the sheath radius.
[0054]
As a result of the heat treatment, it was confirmed that the recovered barium titanate ceramic powder of the object to be processed was heated and fired more uniformly than that of Example 1. Compared with the case of the first embodiment, the increase in the amount of processing and the saving of power consumption compared with the case of the normal flat type three-layer stacking were equal to or more than those in the case of the first embodiment.
[0055]
【The invention's effect】
According to the present invention, the hollow cylindrical sheath containing the workpiece is moved in the furnace while rotating with the transport of the base plate. As a result, the workpiece is subjected to rolling and stirring while the furnace is in contact with the furnace. Because it passes through the inside, uniform and efficient heating is performed, and it is more effective than the conventional method in which a flat type sheath is thinly filled with workpieces, and these sheaths are placed on a base plate and conveyed. Since the thickness of the packed bed can be increased, efficient furnace heat treatment can be performed by shortening the furnace length, and energy utilization efficiency is improved.
[0056]
Claim 5-6 According to the pusher type tunnel furnace described in 1., the rolling speed of the sheath is increased, and by increasing the total number of rotations of the sheath in the furnace, the workpiece is further uniformly and effectively heated. Therefore, more efficient heat treatment can be performed.
[Brief description of the drawings]
FIG. 1 is an overall conceptual diagram of an embodiment of a pusher type tunnel furnace to which the present invention is applied.
2 is a perspective view showing an embodiment of a hollow cylindrical sheath used in the pusher-type tunnel furnace of FIG. 1. FIG.
3 is a plan and side view showing an embodiment of a base plate used in the pusher-type tunnel furnace of FIG. 1. FIG.
4 is a plan and side view showing another embodiment of a base plate used in the pusher type tunnel furnace of FIG. 1. FIG.
FIG. 5 is an exploded perspective view showing another embodiment of a hollow cylindrical sheath used in the pusher type tunnel furnace of FIG. 1;
6 is an exploded perspective view showing still another embodiment of a hollow cylindrical sheath used in the pusher type tunnel furnace of FIG. 1. FIG.
FIG. 7 is an overall conceptual diagram of another embodiment of a pusher type tunnel furnace to which the present invention is applied.
8 is a partial cross-sectional view of FIG.
9 is a perspective view showing an embodiment of a sheath with a cylindrical protrusion used in the pusher-type tunnel furnace of FIG. 7. FIG.
10 is a plan and side view showing an embodiment of a base plate used in the pusher-type tunnel furnace of FIG. 7. FIG.
11 is a plan and side view showing a state in which a sheath is arranged on the base plate of FIG.
12 is a plan view and a side view showing another embodiment of a base plate used in the pusher type tunnel furnace of FIG. 7; FIG.
13 is an exploded perspective view showing another embodiment of the shear with a cylindrical protrusion used in the pusher type tunnel furnace of FIG. 7. FIG.
[Explanation of symbols]
1 base plate
1A base plate
1B base plate
1C base plate
2 opening
2A opening
2B opening
2C opening
2B ₁ Aperture
2B ₂ Aperture
2C ₁ Aperture
2C ₂ Aperture
3 Frame
3B frame
3C frame
3a frame
3b frame
4 Saya
4A Saya
4B Saya
5 lid
6 bolts
7 Washer
8 nuts
9 Packing
10 Bolt hole
11 ridges
12 Entrance worktable
13 Pusher
14 hearth
15 Heating element
16 Chimney
17 Exit platform
18 rails
19 Cylindrical protrusion
20 Saya
20A Saya
21 Screw holes
22 RTD
F Furnace body

Claims

In a pusher-type tunnel furnace equipped with a pusher for sequentially pushing the sheath loaded with the workpiece into the furnace and transporting the inside of the furnace, a hollow cylindrical sheath is used as the sheath, and a base plate having an opening in the hearth The hollow cylindrical sheaths are respectively placed on the hearth so that the central axis thereof is perpendicular to the conveying direction, and the base plate is a pusher. A pusher-type tunnel furnace characterized in that a hollow cylindrical sheath is conveyed along with the base plate while rotating in the opening at the same time as it is conveyed by thrust.

It is a base plate made of a frame provided with a rectangular opening for placing a hollow cylindrical sheath at the center, and among the sides constituting the opening, the base plate in the in-furnace transport direction vertical sides are longer than the axial length of the sheath, according to claim 1, wherein the parallel sides is formed in the D greater than the length represented by the following formula furnace transporting direction of the base plate Base plate used in the pusher type tunnel furnace.
D = 2 (2RH−H ² ) ^1/2 (where R is the radius of the hollow cylindrical sheath, H is the thickness of the base plate)

The base plate used in the pusher type tunnel furnace according to claim 2, wherein the base plate made of the frame body is formed in a U-shaped frame shape lacking one of the frames perpendicular to the in-furnace transport direction of the base plate.

In the hollow cylindrical sheath , a plurality of protrusions parallel to the axial direction of the cylinder are provided on the inner wall surface of the cylinder, and at least one end of the cylinder is configured to be openable for loading and unloading the workpiece. The shear used in the pusher-type tunnel furnace according to claim 1 .

In a pusher-type tunnel furnace equipped with a pusher for sequentially pushing the sheath loaded with workpieces into the furnace and transporting the inside of the furnace, a sheath with cylindrical protrusions at both ends of a hollow cylindrical body is used as the sheath In the furnace, parallel rails for supporting cylindrical projections at both ends of the sheath are arranged in the furnace, and base plates having openings on the hearth are continuously juxtaposed. Each of the hollow cylindrical sheaths is placed in a large number of openings of the base plate row so that the central axis thereof is perpendicular to the transport direction, and the cylindrical protrusions at both ends of the sheath are placed on the rails, The sheath is held so as not to contact the hearth, and the base plate is transported by the thrust of the pusher, and at the same time, the hollow cylindrical sheath is transported with the base plate while rotating in the opening . The featured Turbocharger over-type tunnel furnace.

6. The pusher type tunnel furnace according to claim 5 , wherein the thrust of the pusher is applied to the cylindrical projections at both ends of the sheath.

The pusher type tunnel furnace according to claim 5 or 6 , wherein the diameter of the cylindrical projection provided at both ends of the sheath is 1/2 to 1/3 of the diameter of the hollow cylindrical main body of the sheath. Saya.