JP3659018B2

JP3659018B2 - Water-tight double tube with through hole, method for producing the same, and heat exchange type combustion tube with observation window using the water-tight double tube with through-hole

Info

Publication number: JP3659018B2
Application number: JP27281498A
Authority: JP
Inventors: 宣匡根岸; 貞夫梶塚
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 1998-09-28
Filing date: 1998-09-28
Publication date: 2005-06-15
Anticipated expiration: 2018-09-28
Also published as: JP2000104996A

Description

【０００１】
【発明の属する技術分野】
この発明は、側胴部に透孔を有する水密二重管の構造とその製造方法、および、該透孔付き水密二重管を利用した観察窓付き熱交換型燃焼筒の構成に関するものである。
【０００２】
【従来の技術】
図１２に、従来の透孔付き水密二重管の例として、温水ルームヒーター等の観察窓付き熱交換型燃焼筒に使用される水密二重管の構造断面図を示す。図において、１０１は外筒、１０２および１０３はこの外筒１０１に水密に突設された入口管および出口管、１０４は外筒１０１内に収納された内筒、１０４ａおよび１０４ｂは、それぞれ、内筒１０４の上端部および下端部を外筒１０１の内周とほぼ同径になるように成形した拡管部であり、内筒１０４と外筒１０１がこの拡管部１０４ａ，１０４ｂで全周を水密に溶接されることにより、内筒１０４と外筒１０１の間の間隙１０５は、入口管１０２および出口管１０３と連通した水密の空間を形成する。
【０００３】
また、この従来の透孔付き水密二重管には、内筒１０４の内側と外筒１０１の外側を連通する透孔管１２０が間隙１０５内を貫通して設けられ、透孔管１２０の両端が、それぞれ、内筒１０４および外筒１０１に溶接されることにより、間隙１０５の水密性が保持されるよう構成されている。
【０００４】
次に、この透孔付き水密二重管を温水ルームヒーター用の観察窓付き熱交換型燃焼筒に使用した場合の動作について説明する。図１２において、１１２はバーナーヘッド、１１３は内筒１０４の内部に構成された燃焼室であり、燃料ポンプ（図示せず）により供給された燃料がバーナーヘッド１１２から吐出され燃焼室１１３で燃焼する。一方、水密の間隙１０５内には入口管１０２から温水（図中矢印Ｃ）が供給され、間隙１０５内を通過する間に燃焼ガスと内筒１０４を介して熱交換し、加熱・昇温された温水（図中矢印Ｄ）が出口管１０３から送出される。また、透孔管１２０の外側の端部には、透明板１１５が固定具１１６によって透孔管１２０を塞ぐように固定されており、燃焼ガスが燃焼室１１３から透孔管１２０を通って外部に流出することを防止しながら、燃焼室１１３の燃焼状態を確認できる。
【０００５】
【発明が解決しようとする課題】
しかしながら、上記図１２に示された従来の透孔付き水密二重管は上記のような構造を有するため、内筒１０４および外筒１０１の板厚が薄い場合には、組立前に、予め内筒１０４と外筒１０１の透孔管１２０を挿入する部分に別々に位置を合わせながら穴加工を施し、組立時には両方の穴が同心になるように組み合せ、かつ、透孔管１２０を挿入してから内筒側と外筒側の両方（２個所）を溶接しなければならず、加工工程が複雑で工程数が多いため生産性が悪く、製造コストが高くなるといった問題点があった。また、薄板の場合には、透孔管１２０と内筒１０４および外筒１０１の溶接が難しく、溶接部の強度や水密性にばらつきが生じるといった問題点もあった。
【０００６】
さらに、上記の従来の透孔付き水密二重管を観察窓付き熱交換型燃焼筒として使用した場合には、熱交換効率を上げるために、内筒１０４の板厚を薄くする必要があり、上記のような問題点が顕著であるばかりでなく、他の問題点として、燃焼ガスの熱によって内筒１０４と外筒１０１の間に大きな温度差が生じ、透孔管１２０と内筒１０４および外筒１０１の溶接部に熱応力が発生したり、また、透孔管１２０と内筒１０４との溶接部に高温の腐食性を有する燃焼ガスが直接接触する等の問題点もあった。
【０００７】
この発明は、従来の透孔付き水密二重管および観察窓付き熱交換型燃焼筒の上記のような問題点を解消するためになされたもので、この発明の第１の目的は、加工・組み立てが容易で、工程数が少なく、生産性の向上と低コスト化が可能な透孔付き水密二重管とその製造方法を提供することを目的とする。
【０００８】
また、この発明の第２の目的は、接合部の接合加工がしやすく、接合部の強度や水密性にばらつきの少ない透孔付き水密二重管とその製造方法を提供することを目的とする。
【０００９】
さらに、この発明の第３の目的は、加工・組み立てが容易で、工程数が少なく、生産性の向上と低コスト化が可能で、しかも、燃焼時においても接合部に熱応力等が発生しにくい透孔付き水密二重管構造を有する観察窓付き熱交換型燃焼筒を提供することを目的とする。
【００１０】
【課題を解決するための手段】
この発明に関わる透孔付き水密二重管は、上記の目的を達成するために、外筒と、上記外筒内に挿入された内筒とを備え、上記内筒と上記外筒とが軸方向の上部および下部で全周を水密に接合された水密二重管において、上記内筒の側胴部に上記外筒の内周に接するよう凸部を設け、上記凸部の一部を上記凸部に対応した上記外筒の側胴部とともに折曲重合して、一体の筒状のフランジ部を形成するとともに、筒状の上記フランジ部の内側に上記内筒の内側と上記外筒の外側とを連通する透孔を形成し、さらに、上記フランジ部の端部において上記内筒と上記外筒とを水密に接合するよう構成したものである。
【００１１】
また、この発明に関わる透孔付き水密二重管は、外筒と、上記外筒内に挿入された内筒とを備え、上記内筒と上記外筒とが軸方向の上部および下部で全周を水密に接合された水密二重管において、上記外筒の側胴部に上記内筒の外周に接するよう凹部を設け、上記凹部の一部を上記凹部に対応した上記内筒の側胴部とともに折曲重合して、一体の筒状のフランジ部を形成するとともに、筒状の上記フランジ部の内側に上記内筒の内側と上記外筒の外側とを連通する透孔を形成し、さらに、上記フランジ部の端部において上記内筒と上記外筒とを水密に接合するよう構成したものである。
【００１２】
さらに、この発明に関わる透孔付き水密二重管の製造方法は、内筒の両端部に外筒の内周に接するよう拡管部を形成するとともに、上記内筒の側胴部には上記外筒の内周に接するよう凸部を形成し、上記外筒に上記内筒を組み合せた後、上記凸部と上記凸部に対応した上記外筒の側胴部に対して同時に下穴加工を行い、続いて、バーリング加工によって上記凸部の一部と上記凸部に対応した上記外筒の側胴部を一体に折曲重合して筒状のフランジ部の形成と透孔の加工を同時に行い、最後に上記フランジ部の端部を接合するものである。
【００１３】
また、この発明に関わる透孔付き水密二重管の製造方法は、外筒の両端部に内筒の外周に接するよう縮小部を形成するとともに、上記外筒の側胴部には上記内筒の外周に接するよう凹部を形成し、上記外筒に上記内筒を組み合せた後、上記凹部と上記凹部に対応した上記内筒の側胴部に対して同時に下穴加工を行い、続いて、バーリング加工によって上記凹部の一部と上記凹部に対応した上記内筒の側胴部を一体に折曲重合して筒状のフランジ部の形成と透孔の加工を同時に行い、最後に上記フランジ部の端部を接合するものである。
【００１４】
また、この発明に関わる透孔付き水密二重管の製造方法は、内筒の一端部に外筒の内周に接するよう拡管部を、また、上記外筒の一端部に上記内筒の外周に接するよう縮小部を形成するとともに、上記内筒の側胴部には上記外筒の内周に接するよう凸部を形成し、上記外筒に上記内筒を組み合せた後、上記凸部と上記凸部に対応した上記外筒の側胴部に対して同時に下穴加工を行い、続いて、バーリング加工によって上記凸部の一部と上記凸部に対応した上記外筒の側胴部を一体に折曲重合して筒状のフランジ部の形成と透孔の加工を同時に行い、最後に上記フランジ部の端部を接合するものである。
【００１５】
さらに、この発明に関わる透孔付き水密二重管の製造方法は、内筒の一端部に外筒の内周に接するよう拡管部を、また、上記外筒の一端部に上記内筒の外周に接するよう縮小部を形成するとともに、上記外筒の側胴部には上記内筒の外周に接するよう凹部を形成し、上記外筒に上記内筒を組み合せた後、上記凹部と上記凹部に対応した上記内筒の側胴部に対して同時に下穴加工を行い、続いて、バーリング加工によって上記凹部の一部と上記凹部に対応した上記内筒の側胴部を一体に折曲重合して筒状のフランジ部の形成と透孔の加工を同時に行い、最後に上記フランジ部の端部を接合するものである。
【００１６】
また、この発明に関わる観察窓付き熱交換型燃焼筒は、外筒と、上記外筒内に挿入された内筒と、上記外筒の側胴部の外側に水密に突設された入口管および出口管とを備え、上記内筒と上記外筒とが軸方向の上部および下部で全周を水密に接合されて上記外筒と上記内筒の間に水密の間隙が形成され、上記入口管および上記出口管が上記間隙と連通するよう構成された水密二重管において、上記内筒の側胴部に上記外筒の内周に接するよう凸部を設け、上記凸部の一部を上記凸部に対応した上記外筒の側胴部とともに上記外筒の外側に折曲重合して、一体の筒状のフランジ部を上記外筒の外側に形成するとともに、筒状の上記フランジ部の内側に上記内筒の内側と上記外筒の外側とを連通する透孔を形成し、さらに、上記フランジ部の端部において上記内筒と上記外筒とを水密に接合するとともに、上記フランジ部の上記端部には上記透孔を塞ぐ透明板を設け、また、上記内筒の内側下部にはバーナーヘッドを設けたものである。
【００１７】
また、この発明に関わる観察窓付き熱交換型燃焼筒は、外筒と、上記外筒内に挿入された内筒と、上記外筒の側胴部の外側に水密に突設された入口管および出口管とを備え、上記内筒と上記外筒とが軸方向の上部および下部で全周を水密に接合されて上記外筒と上記内筒の間に水密の間隙が形成され、上記入口管および上記出口管が上記間隙と連通するよう構成された水密二重管において、上記外筒の側胴部に上記内筒の外周に接するよう凹部を設け、上記凹部の一部を上記凹部に対応した上記内筒の側胴部とともに上記内筒の外側に折曲重合して、一体の筒状のフランジ部を上記内筒の外側に形成するとともに、筒状の上記フランジ部の内側に上記内筒の内側と上記外筒の外側とを連通する透孔を形成し、さらに、上記フランジ部の端部において上記内筒と上記外筒とを水密に接合するとともに、上記フランジ部の上記端部には上記透孔を塞ぐ透明板を設け、また、上記内筒の内側下部にはバーナーヘッドを設けたものである。
【００１８】
【発明の実施の形態】
実施の形態１．
図１はこの発明の実施の形態１である透孔付き水密二重管の構造を示す断面図である。図において、１は外筒、２および３は、この外筒１の外側に水密に接合・接続された入口管および出口管、４は外筒１内に挿入された内筒、４ａおよび４ｂは、それぞれ、内筒４の上端部と下端部を外筒１の内周に接するよう成形した拡管部であり、内筒４と外筒１は拡管部４ａおよび４ｂで水密に接合（ロー付けないしは溶接）され、内筒４と外筒１の間に形成される間隙５は入口管２および出口管３と連通した水密の空間を構成している。
【００１９】
また、この実施の形態１においては、内筒４はその側胴部の一部を外筒１の内周にほぼ接するように外側に突出、成形した凸部６を有しており、さらに、凸部６は、そのほぼ中心部分を、対応する外筒１の側胴部とともに外側に向かって一体にバーリング加工されて、外筒１の外側に筒状のフランジ部７が形成されるとともに、筒状のフランジ部７の内側には内筒４の内側から外筒１の外側に貫通する透孔８が形成され、また、フランジ部７の端部７ａにおいて内筒４と外筒１が水密に接合されて、間隙５の水密性が保持されるよう構成されている。
【００２０】
次に、図２〜図６を用いてこの実施の形態１の透孔付き水密二重管の具体的な製造手順について説明する。図２は、外筒１に入口管２および出口管３を接続する工程であり、まず、円筒状の外筒１の下部および上部に接続部１c、１dを形成するとともに穴開け加工がなされ、続いて、この穴の各々に入口管２および出口管３が挿入されて、接続部１c、１dと接合される。
【００２１】
次に、図３に示すように、内筒４の上端部および下端部には、拡管部４ａおよび４ｂが、また、内筒４の側胴部には、凸部６が、それぞれ、外筒１の内周にほぼ接する径になるように同時に成形される。
【００２２】
続いて、図４において、内筒４が外筒１に挿入、組み合わされて二重管を構成し、外筒１と嵌合する拡管部４ａ、４ｂをシーム溶接等で全周にわたって水密に接合した後、凸部６をガイドにして、凸部６のほぼ中心部分とこの凸部６に対応する外筒１の側胴部に下穴９が同時に加工される。
【００２３】
次に、凸部６のバーリング加工について図５および図６を用いて詳しく説明する。図５において、２１は上方部分の外周が凸部６に嵌合し、中心に上記下穴の径より大なる径のガイド穴２２を有する凸型形状のバーリング加工用ガイドであり、２３は、中心にガイド穴２２の径より大なる径の貫通穴２４を有するバーリング加工用メス型、また、２５は、上記下穴９に緩合する先端部分とテーパ状の肩部を有し、ガイド穴２２内を移動可能に嵌挿されたバーリング加工用オス型である。図５に示すように、バーリング加工に先立って、内筒４の内側から凸部６にバーリング加工用ガイド２１を嵌挿するとともに、外筒１の外側にはバーリング加工用メス型２３を配置し、下穴９と貫通穴２４およびガイド穴２２が同心になるように調整される。
【００２４】
続いて、図６に示すように、バーリング加工用ガイド２１とバーリング加工用メス型２３によって内筒４の凸部６とこの凸部６に対応した外筒１の側胴部を密着させた状態で、バーリング加工用ガイド２１のガイド穴２２に嵌挿させたバーリング加工用オス型２５を内筒４の内側から押圧して外側に駆動すれば、凸部６の中心部分が、対応する外筒１の側胴部とともに外側に折り曲げられ（バーリング加工）、外筒１の外側に筒状のフランジ部７が形成されるとともに、同時に、筒状のフランジ部７の内側には、内筒４の内側から外筒１の外側に貫通する透孔８が形成される。
【００２５】
こうして、最後に、バーリング加工によって形成されたフランジ部７の端部７ａで内筒４と外筒１を水密に接合して、透孔付き水密二重管の製造工程が完了する。
【００２６】
以上のように、この実施の形態１に示した透孔付き水密二重管によれば、内筒４の側胴部に外筒１の内周に接するよう凸部６を形成したため、外筒１に内筒４を組み合せた後に、内筒４と外筒１に対して同時に下穴加工を行うことが可能となって、予め内筒４と外筒１に別々に位置を合わせて下穴加工を施しておく必要がなくなり、また、凸部６を形成したことにより、内筒４と外筒１のバーリング加工が可能となってフランジ部７の形成と透孔８の加工が同時に実施でき、さらに、透孔８の加工に伴う接合個所が外筒１の外側に形成された端部７ａの１個所のみとなったので、加工・組み立てが容易で、加工工程が少なくなり、生産性が向上するとともに大幅なコスト低減ができる効果がある。
【００２７】
また、内筒４と外筒１が一体にバーリング加工されているためフランジ部７での内筒４と外筒１の密着性が高くなり、しかも、端部７ａの接合加工が容易であるため、接合部の接合加工が均一になり、信頼性がさらに向上する効果がある。
【００２８】
また、内筒４の両端部に外筒１の内周に接するよう拡管部４ａおよび４ｂが形成されているため、両端部での内筒４と外筒１の密着性が高まって全周接合部の信頼性がさらに向上するとともに、拡管部４ａおよび４ｂがガイドとなって内筒４を外筒１内にしっかりと固定できるため、凸部６と凸部６に対応した外筒１の側胴部の下穴加工やバーリング加工がしやすくなり、生産性が向上する効果がある。
【００２９】
さらに、この実施の形態１に示した透孔付き水密二重管の製造方法によれば、外筒１に内筒４を組み合せた後に内筒４と外筒１に対して同時に下穴加工を行うとともに、バーリング加工を採用することによってフランジ部７の形成と透孔８の加工を同時に行うよう構成したため、加工・組み立てが容易で、加工工程が少なくなり、生産性が向上するとともに大幅なコスト低減ができる効果がある。また、バーリング加工によってフランジ部７での内筒４と外筒１の密着性が高くなるため、接合部の接合加工が均一になり、信頼性がさらに向上する効果がある。
【００３０】
また、内筒４の両端部に外筒１の内周に接するよう拡管部４ａおよび４ｂを形成し、両端部で内筒４と外筒１を接合した後、下穴加工やバーリング加工を行うよう構成したため、拡管部４ａおよび４ｂがガイドとなって内筒４が外筒１内にしっかりと固定され、凸部６と凸部６に対応した外筒１の側胴部の下穴加工やバーリング加工がしやすくなって生産性が向上するとともに、両端部での内筒４と外筒１の密着性が高まって全周接合部の信頼性がさらに向上する効果がある。
【００３１】
実施の形態２．
図７には、この発明の実施の形態２である透孔付き水密二重管の構造を示す。図において、１は外筒、２および３は、この外筒１の外側に水密に接合・接続された入口管および出口管、４は外筒１内に挿入された内筒、１ａおよび１ｂは、それぞれ、外筒１の上端部と下端部を内筒４の外周に接するよう成形した縮小部であり、内筒４と外筒１は縮小部１ａおよび１ｂで水密に接合（ロー付けないしは溶接）され、内筒４と外筒１の間に形成される間隙５は入口管２および出口管３と連通した水密の空間を構成している。
【００３２】
また、この実施の形態２においては、上記の実施の形態１とは逆に、外筒１の側胴部の一部を内筒４の外周にほぼ接するように内側にへこませて凹部１０を形成し、さらに、凹部１０の中心部分は、この凹部１０に対応する内筒４の側胴部とともに内筒４の外側に向かって一体にバーリング加工されて内筒４の外側に筒状のフランジ部７が形成されるとともに、筒状のフランジ部７の内側には内筒４の内側から外筒１の外側に貫通する透孔８が形成され、また、フランジ部７の端部７ａにおいて内筒４と外筒１が水密に接合されることにより、間隙５の水密性が保持されるよう構成されている。
【００３３】
なお、この実施の形態２の製造方法は、上記の実施の形態１との構造上の違いに起因して以下のようになる。（図２〜図６に示した実施の形態１の製造方法において、内筒４の凸部６の加工を外筒１の凹部１０の加工に、また、内筒４の拡管部４ａ、４ｂの加工を外筒１の縮小部１ａ、１ｂの加工に置き換えればよく、以下、図面は省略する。）
【００３４】
まず、円筒状の外筒１の上端部および下端部には縮小部１ａ、１ｂが、また、側胴部には凹部１０が、それぞれ、内筒４の外周にほぼ接する径になるように形成されるとともに、外筒１の下部および上部には接続部１c、１dの成形と穴開け加工がなされ、続いて、この穴の各々に入口管２および出口管３が挿入されて、接続部１c、１dと接合、接続される。
【００３５】
次に、内筒４が外筒１に挿入、組み合わされて二重管を構成し、内筒４と嵌合する縮小部１ａ，１ｂをシーム溶接等で全周にわたって水密に接合した後、凹部１０をガイドにして、凹部１０のほぼ中心部分とこの凹部１０に対応する内筒４の側胴部に下穴９が同時に加工される。
【００３６】
続いて、内筒４の内側に、中心に下穴９の径より大なるガイド穴２２を有するバーリング加工用ガイド２１を、また、外筒１の外側には、外周が凹部１０に嵌合し中心にガイド穴２２の径より大なる貫通穴２４を有するバーリング加工用メス型２３を配置し、外筒１の凹部１０とこの凹部１０に対応した内筒４の側胴部を密着させた状態で、ガイド穴２２内に移動可能に嵌挿したバーリング加工用オス型２５を内筒４の内側から押圧して外側に駆動し、凹部１０とこの凹部１０に対応した内筒４の側胴部を一体にバーリング加工する。
【００３７】
こうして、バーリング加工によって、内筒４の外側に筒状のフランジ部７を形成するとともに、同時に、筒状のフランジ部７の内側に内筒４の内側から外筒１の外側に貫通する透孔８を形成し、最後に、フランジ部７の端部７ａを水密に接合することにより、図７に示した実施の形態２の透孔付き水密二重管の製造工程が完了する。
【００３８】
以上のように、この実施の形態２は実施の形態１の拡管部４ａ、４ｂおよび凸部６を、それぞれ、縮小部１ａ、１ｂおよび凹部１０に置換したものであり、従って、この実施の形態２によっても、生産性の向上、コスト低減、接合部の信頼性の向上等、実施の形態１で述べたものとまったく同様の効果を得ることができる。
【００３９】
なお、上記の実施の形態１および実施の形態２に示した透孔付き水密二重管の製造方法では、入口管２および出口管３を最初の工程で外筒１に接続する例を示したが、上記の工程のどの段階で接続してもよく、また、入口管２および出口管３が接続されていない水密二重管にあっても、まったく同様の効果を奏する。さらに、上記の拡管部４ａおよび４ｂと凸部６の加工、あるいは、縮小部１ａおよび１ｂと凹部１０の加工も、必ずしも同時に行う必要はないが、同時に加工すれば工程数の削減が可能になる効果がある。
【００４０】
実施の形態３．
図８には、この発明による実施の形態３である透孔付き水密二重管の構造を示す。上記の実施の形態１では、内筒４の両端部に拡管部４ａおよび４ｂを設けて内筒４と外筒１を両端部で接合していたが、この実施の形態３では、内筒４の上端部に拡管部４ａを、また、外筒１の下端部に縮小部１ｂを設けて内筒４と外筒１を水密に接合するよう構成している。こうして、この実施の形態３によれば、上記の実施の形態１とは内筒４と外筒１の接合部の形状が異なるだけで本質的にはまったく同じ構成および製造方法を採ることができ、実施の形態１と全く同様の効果が得られる。
【００４１】
実施の形態４．
また、図９には、この発明による実施の形態４として、実施の形態２において、内筒４の一端部を拡管部とし、外筒１と接合した変形例を示す。この実施の形態４においても、上記の実施の形態３と同じく、製造方法も含めて、上記の実施の形態２と全く同様の効果が得られる。
【００４２】
実施の形態５．
なお、上記の実施の形態１ないし実施の形態４では、全て、内筒４の内側から外筒１の外側へとバーリング加工して筒状のフランジ部７を形成した例を示したが、図１０に示す実施の形態５のように、外筒１の外側から内筒４の内側に向けてバーリング加工し、外筒１の内側にフランジ部７を構成しても、上記の実施の形態１ないし実施の形態４と全く同様の効果が得られる。
【００４３】
また、上記の実施の形態１ないし実施の形態５では、内筒４と外筒１の軸方向の長さが同じで、内筒４と外筒１の端部を揃えて接合した例を示したが、どちらかの長さが短い場合は、短い方の端部を長い方の側胴部の途中に接合してもよい。
【００４４】
実施の形態６．
また、図１１には、この発明による実施の形態６として、上記の実施の形態１の透孔付き水密二重管を温水ルームヒーターの観察窓付き熱交換型燃焼筒に適用した場合の構成を示す。図において、１５は透明板であり、固定具１６によりフランジ部７の端部７ａに透孔８を塞ぐように固定されて観察窓を構成している。また、１2は、燃料ポンプ（図示せず）から供給された燃料が吐出、燃焼するバーナヘッドであり、燃焼中、内筒４の内側の空間は燃焼室１３を形成する。なお、図１１において、その他の要素は図１に示した実施の形態１の透孔付き水密二重管と全く同様であり、同一符号は同一部分または相当部分を表わすため、説明を省略する。
【００４５】
この実施の形態６に示された観察窓付き熱交換型燃焼筒の動作は、前述の従来例と同様に以下のようになる。すなわち、入口管２から間隙５内に流入した温水（図中矢印Ａ）は間隙５内を通過する間に燃焼室１３内の燃焼ガスと熱交換して加熱され、昇温された温水（図中矢印Ｂ）が出口管３から流出し、暖房に利用される。また、フランジ部７の端部７ａに取り付けられた透明板１５によって、使用者は、燃焼室１３の外部に燃焼ガスを流出させることなく、透孔８を通して燃焼室１３内の燃焼状態を確認することができる。
【００４６】
以上のように、この実施の形態６によれば、上記の実施の形態１による透孔付き水密二重管を観察窓付き熱交換型燃焼筒として使用したため、上記の実施の形態１で得られたものと全く同様の効果が得られるとともに、加えて、この実施の形態６では、内筒４の凸部とこの凸部に対応する外筒１の側胴部を折り曲げてフランジ部７を形成したため、燃焼時の内筒４と外筒１間の温度差によって生じるひずみがこれらの折り曲げ部分で吸収され、フランジ部７の端部７ａでの熱応力が減少し、接合部の信頼性がさらに向上する効果がある。また、接合個所であるフランジ部７の端部７ａが外筒１の外側にあるため接合部の温度が低くなり、さらに、腐食性を有する高温の燃焼ガスに直接接触することがないため、接合部の信頼性が一層高まる効果がある。また、フランジ部７の端部７ａを透明板１５の受座として利用できるため、新たな受座の加工が不要となる効果もある。
【００４７】
なお、この実施の形態６では、透明板１５を固定具１６を用いてフランジ部７に固定した例を示したが、透明板１５をネジ止め等によってフランジ部７に装着してもよい。また、上記の実施の形態１の他、実施の形態２ないし実施の形態４に示した透孔付き水密二重管を観察窓付き熱交換型燃焼筒として利用しても全く同様の効果が得られる。
【００４８】
【発明の効果】
この発明による透孔付き水密二重管は、以上説明したように、それぞれ、内筒または外筒に凸部または凹部を形成したため、上記内筒と上記外筒に対する同時下穴加工が可能になる他、フランジ部と透孔の同時加工が可能になり、また、上記透孔を形成する際の接合個所も上記フランジ部の端部のみに減少したことから、加工工程が少なくなり、生産性が向上するとともに大幅なコスト低減が可能な透孔付き水密二重管が得られる効果がある。また、上記フランジ部での上記内筒と上記外筒の密着性が高くなり、しかも、上記端部の接合が容易であるため、接合部の信頼性がさらに向上する効果もある。
【００４９】
また、この発明による透孔付き水密二重管は、以上説明したような工程により製造されるため、下穴加工や、透孔加工とフランジ部の形成が同時に行われるため、加工工程が削減され、生産性が向上するとともに大幅なコスト低減ができる効果がある。また、バーリング加工によって上記フランジ部での上記内筒と上記外筒の密着性が高くなり、しかも、上記端部の接合が容易であるため、接合部の接合加工が均一になり、信頼性がさらに向上する効果がある。さらに、上記内筒や上記外筒の端部に、それぞれ、拡管部や縮小部を形成し、上記内筒と上記外筒をしっかり接合、固定したため、下穴加工やバーリング加工がしやすくなって生産性が向上するとともに、上記内筒と上記外筒の接合部での密着性が高まって接合部の信頼性がさらに向上する効果がある。
【００５０】
さらに、この発明による観察窓付き熱交換型燃焼筒は、以上説明したように構成されているので、内筒と外筒に対する同時下穴加工が可能になり、また、フランジ部と透孔が同時に形成されるとともに、上記透孔を形成する際の接合個所も上記フランジ部の端部のみに減少したことから、工程数が少なくなり、生産性が向上するとともに大幅なコスト低減が可能な観察窓付き熱交換型燃焼筒が得られる効果がある。また、上記フランジ部での上記内筒と上記外筒の密着性が高まるとともに、上記凸部または上記凹部の折り曲げ部により上記端部の接合部の燃焼時の熱応力が緩和され、しかも、上記フランジ部を外側に形成したため、上記端部の接合部の温度が低くなるとともに接合部が燃焼ガスに直接接触しないため、接合部の信頼性がさらに向上する効果もある。
【図面の簡単な説明】
【図１】この発明の実施の形態１の透孔付き水密二重管の構造を示す断面図。
【図２】この発明の実施の形態１の透孔付き水密二重管の製造方法（外筒加工）を表わす断面図。
【図３】この発明の実施の形態１の透孔付き水密二重管の製造方法（内筒加工：拡管部および凸部成形）を表わす断面図。
【図４】この発明の実施の形態１の透孔付き水密二重管の製造方法（内外筒組み合せ、拡管部接合、下穴加工）を表わす断面図。
【図５】この発明の実施の形態１の透孔付き水密二重管の製造方法（バーリング加工）を表わす拡大断面図。
【図６】この発明の実施の形態１の透孔付き水密二重管の製造方法（バーリング加工）を表わす拡大断面図。
【図７】この発明の実施の形態２の透孔付き水密二重管の構成を示す断面図。
【図８】この発明の実施の形態３の透孔付き水密二重管の構成を示す断面図。
【図９】この発明の実施の形態４の透孔付き水密二重管の構成を示す断面図。
【図１０】この発明の実施の形態５の透孔付き水密二重管の構成を示す断面図。
【図１１】この発明の実施の形態１の透孔付き水密二重管を観察窓付き熱交換型燃焼筒に適用した場合の構成を示す断面図。
【図１２】従来の観察窓付き熱交換型燃焼筒に用いられる透孔付き水密二重管の構造を示す断面図。
【符号の説明】
１外筒
１ａ、１ｂ縮小部
１ｃ、１ｄ接続部
２入口管
３出口管
４内筒
４ａ、４ｂ拡管部
５間隙
６凸部
７フランジ部
７ａ端部
８透孔
９下穴
１０凹部
１２バーナーヘッド
１３燃焼室
１５透明板
１６固定具
２１バーリング加工用ガイド
２２ガイド穴
２３バーリング加工用メス型
２４貫通穴
２５バーリング加工用オス型[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure of a watertight double pipe having a through hole in a side body portion, a manufacturing method thereof, and a configuration of a heat exchange type combustion cylinder with an observation window using the water tight double pipe with a through hole. .
[0002]
[Prior art]
FIG. 12 shows a structural cross-sectional view of a watertight double tube used in a heat exchange type combustion cylinder with an observation window such as a hot water room heater as an example of a conventional watertight double tube with a through hole. In the figure, 101 is an outer cylinder, 102 and 103 are water inlet-and-outlet pipes protruding from the outer cylinder 101, 104 is an inner cylinder housed in the outer cylinder 101, and 104a and 104b are inner tubes. The tube 104 is an expanded portion in which the upper end and the lower end of the tube 104 are formed to have substantially the same diameter as the inner periphery of the outer tube 101. The inner tube 104 and the outer tube 101 are water-tight over the entire periphery by the expanded portions 104a and 104b. By being welded, a gap 105 between the inner cylinder 104 and the outer cylinder 101 forms a watertight space communicating with the inlet pipe 102 and the outlet pipe 103.
[0003]
In addition, in this conventional watertight double pipe with a through hole, a through hole pipe 120 that communicates the inside of the inner cylinder 104 and the outside of the outer cylinder 101 is provided through the gap 105. Are welded to the inner cylinder 104 and the outer cylinder 101, respectively, so that the watertightness of the gap 105 is maintained.
[0004]
Next, the operation when this watertight double tube with a through hole is used in a heat exchange type combustion cylinder with an observation window for a hot water room heater will be described. In FIG. 12, reference numeral 112 denotes a burner head, and 113 denotes a combustion chamber configured in the inner cylinder 104. Fuel supplied by a fuel pump (not shown) is discharged from the burner head 112 and burns in the combustion chamber 113. . On the other hand, hot water (arrow C in the figure) is supplied into the watertight gap 105 from the inlet pipe 102, and heat exchange is carried out with the combustion gas via the inner cylinder 104 while passing through the gap 105, thereby heating and raising the temperature. Hot water (arrow D in the figure) is sent out from the outlet pipe 103. In addition, a transparent plate 115 is fixed to the outer end portion of the perforated pipe 120 so as to block the perforated pipe 120 by a fixture 116, and combustion gas passes through the perforated pipe 120 from the combustion chamber 113 to the outside. It is possible to check the combustion state of the combustion chamber 113 while preventing it from flowing out.
[0005]
[Problems to be solved by the invention]
However, since the conventional watertight double tube with a through hole shown in FIG. 12 has the above-described structure, when the inner cylinder 104 and the outer cylinder 101 are thin, the inner cylinder 104 and the outer cylinder 101 are pre-assembled in advance. Holes are drilled while aligning the positions of the tube 104 and the outer tube 101 where the through-hole tube 120 is inserted separately. During assembly, the holes are combined so that both holes are concentric, and the through-hole tube 120 is inserted. Therefore, both the inner cylinder side and the outer cylinder side (two locations) must be welded, and the processing process is complicated and the number of processes is large, so that productivity is low and manufacturing cost is high. In the case of a thin plate, it is difficult to weld the through-hole tube 120, the inner cylinder 104, and the outer cylinder 101, and there is a problem in that the strength and water tightness of the welded portion vary.
[0006]
Furthermore, when the above conventional watertight double tube with a through hole is used as a heat exchange type combustion cylinder with an observation window, it is necessary to reduce the thickness of the inner cylinder 104 in order to increase the heat exchange efficiency. Not only the above-mentioned problems are remarkable, but also another problem is that a large temperature difference is generated between the inner cylinder 104 and the outer cylinder 101 due to the heat of the combustion gas, and the through-hole pipe 120 and the inner cylinder 104 and There are also problems such as thermal stress being generated in the welded portion of the outer cylinder 101, and high temperature corrosive combustion gas directly contacting the welded portion between the through-hole tube 120 and the inner cylinder 104.
[0007]
The present invention was made to solve the above-described problems of the conventional watertight double tube with a through hole and the heat exchange type combustion cylinder with an observation window. The first object of the present invention is to An object of the present invention is to provide a watertight double pipe with a through hole that can be easily assembled, has a small number of steps, and can improve productivity and reduce costs, and a method for manufacturing the same.
[0008]
A second object of the present invention is to provide a watertight double tube with a through-hole and a method for manufacturing the same, which are easy to join the joint and have little variation in strength and watertightness of the joint. .
[0009]
Furthermore, the third object of the present invention is that processing and assembly are easy, the number of steps is small, productivity can be improved and cost can be reduced, and thermal stress is generated at the joint even during combustion. An object of the present invention is to provide a heat exchange type combustion cylinder with an observation window having a water-tight double tube structure with a through hole which is difficult.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a watertight double pipe with a through hole according to the present invention includes an outer cylinder and an inner cylinder inserted into the outer cylinder, and the inner cylinder and the outer cylinder are shafts. In the watertight double pipe, the entire circumference of which is watertightly joined at the upper and lower portions in the direction, a convex portion is provided on the side barrel portion of the inner cylinder so as to contact the inner circumference of the outer cylinder, and a part of the convex portion is The side cylinder part of the outer cylinder corresponding to the convex part is bent and polymerized to form an integral cylindrical flange part, and the inner side of the inner cylinder and the outer cylinder are formed inside the cylindrical flange part. A through hole communicating with the outside is formed, and the inner cylinder and the outer cylinder are joined in a watertight manner at the end of the flange.
[0011]
The watertight double pipe with a through hole according to the present invention includes an outer cylinder and an inner cylinder inserted into the outer cylinder, and the inner cylinder and the outer cylinder are all at the upper and lower portions in the axial direction. In the watertight double pipe whose periphery is watertightly joined, a concave portion is provided in the side barrel portion of the outer cylinder so as to contact the outer circumference of the inner cylinder, and a part of the concave portion corresponds to the concave portion. Bending together with the part to form an integral cylindrical flange part, and forming a through hole communicating the inner side of the inner cylinder and the outer side of the outer cylinder inside the cylindrical flange part, Further, the inner cylinder and the outer cylinder are joined in a watertight manner at the end of the flange portion.
[0012]
Further, in the method for manufacturing a watertight double pipe with a through hole according to the present invention, a pipe expanding portion is formed at both end portions of the inner cylinder so as to be in contact with the inner periphery of the outer cylinder, and the outer cylinder is provided on the side barrel portion of the inner cylinder. A convex part is formed so as to contact the inner periphery of the cylinder, and after the inner cylinder is combined with the outer cylinder, pilot hole machining is simultaneously performed on the convex part and the side barrel part of the outer cylinder corresponding to the convex part. Next, a part of the convex part and a side body part of the outer cylinder corresponding to the convex part are bent and polymerized integrally by burring to form a cylindrical flange part and process a through hole at the same time. Finally, the end of the flange portion is joined.
[0013]
Further, in the method for manufacturing a watertight double pipe with a through hole according to the present invention, the reduced diameter portion is formed at both ends of the outer cylinder so as to be in contact with the outer periphery of the inner cylinder, and the inner cylinder is formed on the side barrel of the outer cylinder. After forming a recess so as to contact the outer periphery of the outer cylinder, combining the inner cylinder with the outer cylinder, simultaneously performing pilot hole processing on the recess and the side barrel of the inner cylinder corresponding to the recess, A part of the concave portion and the side barrel portion of the inner cylinder corresponding to the concave portion are integrally bent and polymerized by burring to simultaneously form a cylindrical flange portion and process a through hole. Finally, the flange portion Are joined.
[0014]
Further, in the method for manufacturing a watertight double pipe with a through-hole according to the present invention, a pipe expanding part is in contact with the inner circumference of the outer cylinder at one end of the inner cylinder, and the outer circumference of the inner cylinder is arranged at one end of the outer cylinder. And forming a convex portion on the side barrel of the inner cylinder so as to be in contact with the inner periphery of the outer cylinder, and combining the inner cylinder with the outer cylinder. Pilot hole processing is simultaneously performed on the side barrel portion of the outer cylinder corresponding to the convex portion, and then a part of the convex portion and the side barrel portion of the outer cylinder corresponding to the convex portion are formed by burring. They are bent together to form a cylindrical flange portion and process a through hole at the same time, and finally join the end portions of the flange portion.
[0015]
Furthermore, the manufacturing method of the watertight double pipe with a through hole according to the present invention includes a tube expanding portion at one end of the inner cylinder so as to contact the inner periphery of the outer cylinder, and an outer periphery of the inner cylinder at one end of the outer cylinder. And forming a recess in the side barrel of the outer cylinder so as to contact the outer periphery of the inner cylinder. After the inner cylinder is combined with the outer cylinder, the recess and the recess are A pilot hole is simultaneously drilled in the corresponding side barrel of the inner cylinder, and then a part of the concave portion and the side barrel of the inner cylinder corresponding to the concave portion are integrally bent and polymerized by burring. The cylindrical flange portion is formed and the through hole is simultaneously processed, and finally the end portion of the flange portion is joined.
[0016]
Further, the heat exchange type combustion cylinder with an observation window according to the present invention includes an outer cylinder, an inner cylinder inserted into the outer cylinder, and an inlet pipe protruding in a watertight manner on the outer side of a side body portion of the outer cylinder. And an outlet pipe, and the inner cylinder and the outer cylinder are joined together in a watertight manner at the upper and lower portions in the axial direction to form a watertight gap between the outer cylinder and the inner cylinder, and the inlet In the watertight double pipe configured such that the pipe and the outlet pipe communicate with the gap, a convex portion is provided on the side barrel portion of the inner cylinder so as to contact the inner periphery of the outer cylinder, and a part of the convex portion is provided. A cylindrical flange portion is formed on the outer side of the outer cylinder by bending and superposing on the outer side of the outer cylinder together with the side barrel portion of the outer cylinder corresponding to the convex portion, and the cylindrical flange portion A through hole is formed on the inner side of the inner cylinder and the outer side of the outer cylinder. In addition, the inner cylinder and the outer cylinder are joined in a watertight manner, a transparent plate that closes the through hole is provided at the end of the flange portion, and a burner head is provided at the inner lower portion of the inner cylinder. Is.
[0017]
Further, the heat exchange type combustion cylinder with an observation window according to the present invention includes an outer cylinder, an inner cylinder inserted into the outer cylinder, and an inlet pipe protruding in a watertight manner on the outer side of a side body portion of the outer cylinder. And an outlet pipe, and the inner cylinder and the outer cylinder are joined together in a watertight manner at the upper and lower portions in the axial direction to form a watertight gap between the outer cylinder and the inner cylinder, and the inlet In the watertight double pipe configured so that the pipe and the outlet pipe communicate with the gap, a concave portion is provided in a side body portion of the outer cylinder so as to contact an outer periphery of the inner cylinder, and a part of the concave portion is provided in the concave section. The inner cylinder is bent and polymerized together with the corresponding side cylinder of the inner cylinder to form an integral cylindrical flange on the outer side of the inner cylinder, and the inner side of the cylindrical flange is A through hole is formed to communicate the inner side of the inner cylinder and the outer side of the outer cylinder, and further, at the end of the flange part In addition, the inner cylinder and the outer cylinder are joined in a watertight manner, a transparent plate that closes the through hole is provided at the end of the flange portion, and a burner head is provided at the inner lower portion of the inner cylinder. Is.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
1 is a cross-sectional view showing the structure of a watertight double pipe with a through hole according to Embodiment 1 of the present invention. In the figure, 1 is an outer cylinder, 2 and 3 are inlet pipes and outlet pipes joined and connected to the outside of the outer cylinder 1 in a watertight manner, 4 is an inner cylinder inserted into the outer cylinder 1, 4a and 4b are These are expanded pipe parts formed so that the upper end and the lower end of the inner cylinder 4 are in contact with the inner periphery of the outer cylinder 1. The gap 5 formed between the inner cylinder 4 and the outer cylinder 1 is a watertight space communicating with the inlet pipe 2 and the outlet pipe 3.
[0019]
Moreover, in this Embodiment 1, the inner cylinder 4 has the convex part 6 which protruded and molded outside so that a part of the side trunk | drum might substantially contact | connect the inner periphery of the outer cylinder 1, The convex portion 6 is subjected to burring integrally with the side barrel portion of the corresponding outer cylinder 1 toward the outside, and a cylindrical flange portion 7 is formed on the outer side of the outer cylinder 1. A through-hole 8 is formed inside the cylindrical flange portion 7 so as to penetrate from the inner side of the inner tube 4 to the outer side of the outer tube 1, and the inner tube 4 and the outer tube 1 are watertight at the end 7 a of the flange portion 7. The watertightness of the gap 5 is maintained.
[0020]
Next, a specific manufacturing procedure of the watertight double pipe with a through hole according to the first embodiment will be described with reference to FIGS. FIG. 2 is a process of connecting the inlet pipe 2 and the outlet pipe 3 to the outer cylinder 1. First, the connecting portions 1 c and 1 d are formed on the lower and upper parts of the cylindrical outer cylinder 1 and drilling is performed. Subsequently, the inlet pipe 2 and the outlet pipe 3 are inserted into each of the holes and joined to the connecting portions 1c and 1d.
[0021]
Next, as shown in FIG. 3, the expanded portions 4 a and 4 b are provided at the upper end portion and the lower end portion of the inner cylinder 4, and the convex portion 6 is provided at the side body portion of the inner cylinder 4, respectively. At the same time, it is molded so as to have a diameter that is substantially in contact with the inner circumference of one.
[0022]
Subsequently, in FIG. 4, the inner cylinder 4 is inserted into and combined with the outer cylinder 1 to form a double pipe, and the expanded portions 4a and 4b fitted to the outer cylinder 1 are joined in a watertight manner over the entire circumference by seam welding or the like. After that, with the convex portion 6 as a guide, the pilot hole 9 is simultaneously processed in the substantially central portion of the convex portion 6 and the side barrel portion of the outer cylinder 1 corresponding to the convex portion 6.
[0023]
Next, the burring process of the convex part 6 is demonstrated in detail using FIG. 5 and FIG. In FIG. 5, 21 is a convex burring processing guide having a guide hole 22 having a diameter larger than the diameter of the pilot hole at the center, the outer periphery of the upper portion being fitted to the convex portion 6, A female type for burring having a through hole 24 having a diameter larger than the diameter of the guide hole 22 at the center, and 25 has a tip portion loosely fitted to the pilot hole 9 and a tapered shoulder, and the guide hole 22 is a male type for burring work that is inserted so as to be movable in the interior. As shown in FIG. 5, prior to burring, a burring guide 21 is fitted into the convex portion 6 from the inner side of the inner cylinder 4, and a burring female die 23 is arranged on the outer side of the outer cylinder 1. The pilot hole 9, the through hole 24, and the guide hole 22 are adjusted to be concentric.
[0024]
Subsequently, as shown in FIG. 6, a state in which the convex portion 6 of the inner cylinder 4 and the side barrel portion of the outer cylinder 1 corresponding to the convex portion 6 are brought into close contact with each other by the guide 21 for burring and the female die 23 for burring. Then, if the burring male die 25 fitted in the guide hole 22 of the burring guide 21 is pressed from the inner side of the inner cylinder 4 and driven to the outer side, the central portion of the convex portion 6 becomes the corresponding outer cylinder. 1 is bent outward (burring process) together with the side barrel portion 1, and a cylindrical flange portion 7 is formed on the outer side of the outer tube 1. At the same time, on the inner side of the cylindrical flange portion 7, A through hole 8 penetrating from the inside to the outside of the outer cylinder 1 is formed.
[0025]
Thus, finally, the inner cylinder 4 and the outer cylinder 1 are joined in a watertight manner at the end 7a of the flange portion 7 formed by burring, and the manufacturing process of the watertight double pipe with a through hole is completed.
[0026]
As described above, according to the watertight double tube with a through-hole shown in the first embodiment, the convex portion 6 is formed on the side barrel portion of the inner cylinder 4 so as to be in contact with the inner periphery of the outer cylinder 1. After the inner cylinder 4 is combined with the inner cylinder 4, it is possible to simultaneously drill the pilot holes in the inner cylinder 4 and the outer cylinder 1, and the positions of the inner cylinder 4 and the outer cylinder 1 are separately adjusted in advance. It is not necessary to perform the processing, and the convex portion 6 is formed, so that the inner tube 4 and the outer tube 1 can be burred, and the flange portion 7 and the through-hole 8 can be formed simultaneously. In addition, since the joint portion associated with the processing of the through-hole 8 is only one portion of the end portion 7a formed on the outer side of the outer cylinder 1, processing / assembly is easy, processing steps are reduced, and productivity is increased. There is an effect that the cost can be greatly reduced while improving.
[0027]
Further, since the inner cylinder 4 and the outer cylinder 1 are integrally burring processed, the adhesiveness between the inner cylinder 4 and the outer cylinder 1 at the flange portion 7 is increased, and the end portion 7a is easily joined. In addition, the bonding process of the bonded portion becomes uniform, and the reliability is further improved.
[0028]
In addition, since the expanded portions 4a and 4b are formed at both ends of the inner cylinder 4 so as to contact the inner periphery of the outer cylinder 1, the adhesion between the inner cylinder 4 and the outer cylinder 1 at both ends is increased, and the entire circumference is joined. The reliability of the portion is further improved, and the expanded tube portions 4a and 4b can serve as a guide to firmly fix the inner tube 4 in the outer tube 1. Therefore, the side of the outer tube 1 corresponding to the protruding portion 6 and the protruding portion 6 This makes it easier to drill holes and burring on the body and improve productivity.
[0029]
Furthermore, according to the method for manufacturing a watertight double pipe with a through hole shown in the first embodiment, after the inner cylinder 4 is combined with the outer cylinder 1, the pilot holes are simultaneously drilled into the inner cylinder 4 and the outer cylinder 1. In addition, by adopting burring processing, the formation of the flange portion 7 and the processing of the through hole 8 are performed at the same time, so processing and assembly are easy, processing steps are reduced, productivity is improved, and significant cost is increased. There is an effect that can be reduced. Moreover, since the adhesiveness of the inner cylinder 4 and the outer cylinder 1 in the flange part 7 becomes high by burring process, the joining process of a junction part becomes uniform and there exists an effect which further improves reliability.
[0030]
In addition, tube expansion parts 4a and 4b are formed at both ends of the inner cylinder 4 so as to contact the inner periphery of the outer cylinder 1, and after the inner cylinder 4 and the outer cylinder 1 are joined at both ends, pilot hole processing and burring processing are performed. Therefore, the inner pipe 4 is firmly fixed in the outer cylinder 1 with the expanded pipe portions 4a and 4b serving as a guide, and the pilot hole processing of the side barrel portion of the outer cylinder 1 corresponding to the convex portion 6 and the convex portion 6 The burring process is facilitated and the productivity is improved, and the adhesion between the inner cylinder 4 and the outer cylinder 1 at both end portions is enhanced, and the reliability of the all-around joint portion is further improved.
[0031]
Embodiment 2. FIG.
FIG. 7 shows the structure of a watertight double pipe with a through hole, which is Embodiment 2 of the present invention. In the figure, 1 is an outer cylinder, 2 and 3 are inlet and outlet pipes joined and connected to the outside of the outer cylinder 1 in a watertight manner, 4 is an inner cylinder inserted into the outer cylinder 1, and 1 a and 1 b are These are reduced parts formed so that the upper end and the lower end of the outer cylinder 1 are in contact with the outer periphery of the inner cylinder 4, and the inner cylinder 4 and the outer cylinder 1 are joined in a watertight manner (brazing or welding) at the reduced parts 1a and 1b. The gap 5 formed between the inner cylinder 4 and the outer cylinder 1 constitutes a watertight space communicating with the inlet pipe 2 and the outlet pipe 3.
[0032]
In the second embodiment, contrary to the first embodiment, a part of the side barrel portion of the outer cylinder 1 is recessed inward so as to substantially contact the outer periphery of the inner cylinder 4. Further, the central portion of the concave portion 10 is integrally burringed toward the outside of the inner cylinder 4 together with the side barrel portion of the inner cylinder 4 corresponding to the concave portion 10 to form a cylindrical shape on the outer side of the inner cylinder 4. A flange portion 7 is formed, and a through-hole 8 that penetrates from the inner side of the inner tube 4 to the outer side of the outer tube 1 is formed on the inner side of the cylindrical flange portion 7, and at the end 7 a of the flange portion 7. The inner cylinder 4 and the outer cylinder 1 are joined in a watertight manner so that the watertightness of the gap 5 is maintained.
[0033]
The manufacturing method of the second embodiment is as follows due to the structural difference from the first embodiment. (In the manufacturing method of Embodiment 1 shown in FIGS. 2 to 6, the processing of the convex portion 6 of the inner cylinder 4 is changed to the processing of the concave portion 10 of the outer cylinder 1, and the expansion portions 4 a and 4 b of the inner cylinder 4 are processed. (The processing may be replaced with the processing of the reduced portions 1a and 1b of the outer cylinder 1, and the drawings are omitted below.)
[0034]
First, the reduced portions 1a and 1b are formed at the upper end portion and the lower end portion of the cylindrical outer tube 1, and the concave portion 10 is formed at the side body portion so as to have a diameter substantially in contact with the outer periphery of the inner tube 4. At the same time, the connecting portions 1c and 1d are formed and drilled in the lower and upper portions of the outer cylinder 1. Subsequently, the inlet tube 2 and the outlet tube 3 are inserted into each of the holes, and the connecting portion 1c. 1d and joined.
[0035]
Next, the inner cylinder 4 is inserted into and combined with the outer cylinder 1 to form a double pipe, and the reduced portions 1a and 1b fitted to the inner cylinder 4 are joined in a watertight manner over the entire circumference by seam welding or the like, 10 is used as a guide, and the pilot holes 9 are simultaneously processed in the substantially central portion of the recess 10 and the side barrel of the inner cylinder 4 corresponding to the recess 10.
[0036]
Subsequently, a burring guide 21 having a guide hole 22 larger than the diameter of the pilot hole 9 at the center is fitted inside the inner cylinder 4, and the outer periphery is fitted into the recess 10 outside the outer cylinder 1. A state where a female die 23 for burring processing having a through hole 24 larger than the diameter of the guide hole 22 is disposed at the center, and the concave portion 10 of the outer cylinder 1 and the side barrel portion of the inner cylinder 4 corresponding to the concave portion 10 are in close contact with each other. Then, the burring male die 25 movably fitted in the guide hole 22 is pressed from the inner side of the inner cylinder 4 and driven to the outer side, and the concave part 10 and the side barrel part of the inner cylinder 4 corresponding to the concave part 10 are driven. Are burringed together.
[0037]
In this way, the cylindrical flange portion 7 is formed outside the inner cylinder 4 by burring, and at the same time, a through-hole penetrating from the inner side of the inner cylinder 4 to the outer side of the outer cylinder 1 inside the cylindrical flange portion 7. 8, and finally, the end portion 7a of the flange portion 7 is joined in a watertight manner, whereby the manufacturing process of the watertight double tube with a through hole in the second embodiment shown in FIG. 7 is completed.
[0038]
As described above, the second embodiment is obtained by replacing the expanded portions 4a and 4b and the convex portion 6 of the first embodiment with the reduced portions 1a and 1b and the concave portion 10, respectively. According to 2 as well, it is possible to obtain the same effects as those described in the first embodiment, such as improvement in productivity, cost reduction, and improvement in reliability of the joint.
[0039]
In addition, in the manufacturing method of the watertight double pipe with a through-hole shown in said Embodiment 1 and Embodiment 2, the example which connected the inlet pipe 2 and the outlet pipe 3 to the outer cylinder 1 at the first process was shown. However, it may be connected at any stage of the above process, and the same effect can be obtained even in a watertight double pipe to which the inlet pipe 2 and the outlet pipe 3 are not connected. Further, the processing of the above-mentioned expanded portions 4a and 4b and the convex portion 6 or the processing of the reduced portions 1a and 1b and the concave portion 10 do not necessarily have to be performed at the same time. effective.
[0040]
Embodiment 3 FIG.
FIG. 8 shows the structure of a watertight double pipe with a through hole according to Embodiment 3 of the present invention. In the first embodiment, the expanded tubes 4a and 4b are provided at both ends of the inner cylinder 4 and the inner cylinder 4 and the outer cylinder 1 are joined at both ends. However, in the third embodiment, the inner cylinder 4 An expanded tube portion 4a is provided at the upper end of the outer tube 1 and a reduced portion 1b is provided at the lower end of the outer tube 1 so that the inner tube 4 and the outer tube 1 are joined in a watertight manner. Thus, according to the third embodiment, essentially the same configuration and manufacturing method can be adopted as in the first embodiment, except that the shape of the joint portion between the inner cylinder 4 and the outer cylinder 1 is different. The same effect as in the first embodiment can be obtained.
[0041]
Embodiment 4 FIG.
FIG. 9 shows a modification in which one end portion of the inner cylinder 4 is a tube expansion portion and is joined to the outer cylinder 1 as the fourth embodiment according to the present invention. In the fourth embodiment, as in the third embodiment, the same effects as in the second embodiment including the manufacturing method can be obtained.
[0042]
Embodiment 5 FIG.
In the first to fourth embodiments described above, an example is shown in which the cylindrical flange portion 7 is formed by burring from the inner side of the inner cylinder 4 to the outer side of the outer cylinder 1. As in the fifth embodiment shown in FIG. 10, even if the burring process is performed from the outer side of the outer cylinder 1 toward the inner side of the inner cylinder 4 and the flange portion 7 is formed inside the outer cylinder 1, the above-described first embodiment In addition, the same effects as those of the fourth embodiment can be obtained.
[0043]
In the first to fifth embodiments, the inner cylinder 4 and the outer cylinder 1 have the same axial length, and the end portions of the inner cylinder 4 and the outer cylinder 1 are aligned and joined. However, when either of the lengths is short, the shorter end may be joined in the middle of the longer side trunk.
[0044]
Embodiment 6 FIG.
Further, FIG. 11 shows, as Embodiment 6 according to the present invention, a configuration in which the watertight double tube with a through hole of Embodiment 1 is applied to a heat exchange type combustion cylinder with an observation window of a hot water room heater. Show. In the figure, reference numeral 15 denotes a transparent plate, which is fixed to the end portion 7a of the flange portion 7 by a fixture 16 so as to close the through-hole 8, thereby constituting an observation window. Reference numeral 12 denotes a burner head from which fuel supplied from a fuel pump (not shown) is discharged and burned. The space inside the inner cylinder 4 forms a combustion chamber 13 during combustion. In FIG. 11, the other elements are the same as those of the water-tight double tube with a through hole of the first embodiment shown in FIG. 1, and the same reference numerals represent the same or corresponding parts, and thus the description thereof is omitted.
[0045]
The operation of the heat exchange type combustion cylinder with the observation window shown in the sixth embodiment is as follows as in the above-described conventional example. That is, the hot water flowing into the gap 5 from the inlet pipe 2 (arrow A in the figure) is heated by exchanging heat with the combustion gas in the combustion chamber 13 while passing through the gap 5, and the heated hot water (FIG. The middle arrow B) flows out from the outlet pipe 3 and is used for heating. Further, the transparent plate 15 attached to the end 7 a of the flange portion 7 allows the user to check the combustion state in the combustion chamber 13 through the through-hole 8 without causing the combustion gas to flow out of the combustion chamber 13. be able to.
[0046]
As described above, according to the sixth embodiment, since the watertight double tube with a through hole according to the first embodiment is used as a heat exchange type combustion cylinder with an observation window, it is obtained in the first embodiment. In the sixth embodiment, the flange portion 7 is formed by bending the convex portion of the inner cylinder 4 and the side barrel portion of the outer cylinder 1 corresponding to the convex portion. Therefore, the distortion caused by the temperature difference between the inner cylinder 4 and the outer cylinder 1 during combustion is absorbed by these bent portions, the thermal stress at the end portion 7a of the flange portion 7 is reduced, and the reliability of the joint portion is further increased. There is an effect to improve. Further, since the end 7a of the flange portion 7 which is a joining portion is outside the outer cylinder 1, the temperature of the joining portion is lowered, and furthermore, since the end portion 7a is not in direct contact with the corrosive high-temperature combustion gas, This has the effect of further improving the reliability of the part. Further, since the end portion 7a of the flange portion 7 can be used as a seat for the transparent plate 15, there is an effect that processing of a new seat becomes unnecessary.
[0047]
In the sixth embodiment, an example in which the transparent plate 15 is fixed to the flange portion 7 using the fixing tool 16 is shown. However, the transparent plate 15 may be attached to the flange portion 7 by screwing or the like. In addition to the first embodiment, the same effect can be obtained even if the watertight double tube with a through hole shown in the second to fourth embodiments is used as a heat exchange type combustion cylinder with an observation window. It is done.
[0048]
【The invention's effect】
As described above, the water-tight double pipe with a through hole according to the present invention has a convex portion or a concave portion formed in the inner cylinder or the outer cylinder, respectively, so that simultaneous pilot hole processing for the inner cylinder and the outer cylinder becomes possible. In addition, simultaneous processing of the flange portion and the through hole is possible, and the joint portion when forming the through hole is reduced only to the end portion of the flange portion, so that the processing steps are reduced and the productivity is reduced. There is an effect that a watertight double pipe with a through-hole capable of being improved and greatly reduced in cost can be obtained. Moreover, since the adhesiveness between the inner cylinder and the outer cylinder at the flange portion is increased and the end portions are easily joined, there is an effect of further improving the reliability of the joined portion.
[0049]
Further, since the watertight double pipe with a through hole according to the present invention is manufactured by the process as described above, the preparation process is performed and the through hole processing and the formation of the flange portion are performed at the same time. As a result, productivity is improved and cost can be significantly reduced. In addition, the burring process increases the adhesion between the inner cylinder and the outer cylinder at the flange part, and since the end part can be easily joined, the joining process of the joined part becomes uniform and the reliability is improved. There is a further improvement effect. Furthermore, the tube expansion part and the reduction part are formed at the end of the inner cylinder and the outer cylinder, respectively, and the inner cylinder and the outer cylinder are firmly joined and fixed. While improving productivity, the adhesiveness in the junction part of the said inner cylinder and the said outer cylinder increases, and there exists an effect which further improves the reliability of a junction part.
[0050]
Furthermore, since the heat exchange type combustion cylinder with an observation window according to the present invention is configured as described above, it is possible to simultaneously prepare a pilot hole for the inner cylinder and the outer cylinder, and the flange portion and the through hole are simultaneously provided. In addition to the formation of the through-holes, the number of joints has been reduced to the end of the flange, reducing the number of processes, improving productivity, and significantly reducing costs. There is an effect that an attached heat exchange type combustion cylinder is obtained. In addition, adhesion between the inner cylinder and the outer cylinder at the flange portion is enhanced, and thermal stress at the time of combustion at the joint portion of the end portion is relieved by the bent portion of the convex portion or the concave portion, and Since the flange portion is formed on the outside, the temperature of the joint portion at the end portion is lowered, and the joint portion does not directly contact the combustion gas, so that the reliability of the joint portion is further improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing the structure of a watertight double tube with a through hole according to Embodiment 1 of the present invention.
FIG. 2 is a cross-sectional view showing a method (outer cylinder processing) for manufacturing a watertight double pipe with a through-hole according to Embodiment 1 of the present invention.
FIG. 3 is a cross-sectional view illustrating a method for manufacturing a watertight double tube with a through hole according to Embodiment 1 of the present invention (inner tube processing: tube expansion portion and convex portion molding).
FIG. 4 is a cross-sectional view illustrating a method for manufacturing a watertight double pipe with a through hole according to Embodiment 1 of the present invention (combination of inner and outer cylinders, pipe expansion joint joining, pilot hole machining).
FIG. 5 is an enlarged cross-sectional view showing a method (burring process) for manufacturing a watertight double tube with a through hole according to Embodiment 1 of the present invention.
6 is an enlarged cross-sectional view showing a method (burring process) for manufacturing a watertight double tube with a through hole according to Embodiment 1 of the present invention. FIG.
FIG. 7 is a cross-sectional view showing a configuration of a watertight double pipe with a through hole according to a second embodiment of the present invention.
FIG. 8 is a cross-sectional view showing a configuration of a watertight double pipe with a through hole according to a third embodiment of the present invention.
FIG. 9 is a cross-sectional view showing a configuration of a watertight double pipe with a through hole according to a fourth embodiment of the present invention.
FIG. 10 is a sectional view showing the structure of a watertight double pipe with a through hole according to a fifth embodiment of the present invention.
FIG. 11 is a cross-sectional view showing a configuration when the watertight double tube with a through hole according to the first embodiment of the present invention is applied to a heat exchange type combustion cylinder with an observation window.
FIG. 12 is a cross-sectional view showing the structure of a watertight double tube with a through hole used in a conventional heat exchange type combustion cylinder with an observation window.
[Explanation of symbols]
1 outer cylinder
1a, 1b Reduction part
1c, 1d connection
2 inlet pipe
3 outlet pipe
4 inner cylinder
4a, 4b Expanded part
5 gap
6 Convex
7 Flange
7a end
8 Through hole
9 Pilot hole
10 recess
12 Burner head
13 Combustion chamber
15 Transparent plate
16 Fixture
21 Burling guide
22 Guide hole
23 Female type for burring
24 Through hole
25 Male type for burring

Claims

A watertight double pipe comprising an outer cylinder and an inner cylinder inserted into the outer cylinder, wherein the inner cylinder and the outer cylinder are watertightly joined at the upper and lower portions in the axial direction. A convex portion is provided on the side barrel portion of the cylinder so as to be in contact with the inner periphery of the outer cylinder, and a part of the convex portion is bent and polymerized together with the side barrel portion of the outer cylinder corresponding to the convex portion. A through-hole that communicates the inner side of the inner cylinder and the outer side of the outer cylinder is formed inside the flange part, and the inner part is formed at the end of the flange part. A watertight double tube with a through hole, characterized in that the tube and the outer tube are joined in a watertight manner.

A watertight double pipe comprising an outer cylinder and an inner cylinder inserted into the outer cylinder, wherein the inner cylinder and the outer cylinder are watertightly joined at the upper and lower portions in the axial direction. A concave portion is provided in the side barrel portion of the cylinder so as to contact the outer periphery of the inner cylinder, and a part of the concave portion is bent and polymerized together with the side barrel portion of the inner cylinder corresponding to the concave portion, so that an integral cylindrical flange portion is formed. And forming a through-hole that communicates the inside of the inner cylinder and the outside of the outer cylinder on the inside of the cylindrical flange, and further, the inner cylinder and the outer at the end of the flange. A watertight double tube with a through hole, characterized in that the tube is watertightly joined.

The manufacturing method of the watertight double pipe with a through-hole of Claim 1 provided with the following processes.
(A) A step of forming a tube expansion portion at the upper end portion and the lower end portion of the inner cylinder so as to be substantially in contact with the inner periphery of the outer cylinder. (B) Protruding portions on the outer side of the side barrel portion of the inner cylinder so as to be substantially in contact with the inner periphery of the outer cylinder. Forming step (c) inserting the inner cylinder into the outer cylinder, and joining the expanded pipe part and the outer cylinder in a water-tight manner over the entire circumference (d) the convex part and the outer cylinder corresponding to the convex part A step of integrally processing a pilot hole penetrating the inner cylinder and the outer cylinder in the side barrel portion of the outer cylinder. (E) The outer cylinder corresponding to the convex portion by using the pilot hole as a guide. Burring together with the side barrel portion to form an integral cylindrical flange portion, and at the same time, the inner side of the inner cylinder and the outer side of the outer cylinder communicate with the inner side of the cylindrical flange portion. Forming a hole;
(F) A step of joining the inner cylinder and the outer cylinder in a water-tight manner at an end of the flange portion formed by burring.

The manufacturing method of the watertight double pipe with a through-hole of Claim 2 provided with the following processes.
(A) A step of forming a reduced portion at the upper end and lower end of the outer cylinder so as to substantially contact the outer periphery of the inner cylinder (b) A step of forming a recess in the side barrel of the outer cylinder so as to substantially contact the outer periphery of the inner cylinder ( c) Inserting the inner cylinder into the outer cylinder and watertightly joining the reduced portion and the inner cylinder over the entire circumference (d) In the concave portion and the side barrel portion of the inner cylinder corresponding to the concave portion, Step of integrally processing pilot holes penetrating through the inner cylinder and the outer cylinder (e) Using the pilot hole as a guide, part of the concave portion is integrated with the side barrel portion of the inner cylinder corresponding to the concave portion. Processing to form an integral cylindrical flange portion, and at the same time, forming a through hole communicating the inner side of the inner cylinder and the outer side of the outer cylinder inside the cylindrical flange portion.
(F) A step of joining the inner cylinder and the outer cylinder in a water-tight manner at an end of the flange portion formed by burring.

The manufacturing method of the watertight double pipe with a through-hole of Claim 1 provided with the following processes.
(A) A step of forming a tube expansion portion at one end portion of the inner cylinder so as to substantially contact the inner periphery of the outer tube (b) A step of forming a convex portion outside the side barrel portion of the inner cylinder so as to substantially contact the inner periphery of the outer cylinder. (C) a step of forming a reduced portion at one end of the outer cylinder so as to substantially contact the outer periphery of the inner cylinder; (d) inserting the inner cylinder into the outer cylinder, and connecting the expanded pipe section and the outer cylinder, respectively, A step of water-tightly joining the reduced portion and the inner cylinder over the entire circumference (e) a lower body penetrating the inner cylinder and the outer cylinder in the side barrel of the outer cylinder corresponding to the convex part and the convex part (F) Using the pilot hole as a guide, a part of the convex portion is integrally burred together with the side barrel portion of the outer cylinder corresponding to the convex portion, and an integral cylindrical flange is formed. At the same time, the inner side of the inner cylinder and the outer side of the outer cylinder inside the cylindrical flange part Forming a through hole that communicates.
(G) A step of joining the inner cylinder and the outer cylinder in a watertight manner at an end of the flange portion formed by burring.

The manufacturing method of the watertight double pipe with a through-hole of Claim 2 provided with the following processes.
(A) a step of forming a reduced portion at one end of the outer cylinder so as to be substantially in contact with the outer periphery of the inner cylinder; (b) a step of forming a recess in the side barrel of the outer cylinder so as to be substantially in contact with the outer periphery of the inner cylinder; A step of forming a tube expansion portion at one end of the inner tube so as to substantially contact the inner periphery of the tube; (d) inserting the inner tube into the outer tube, and respectively reducing the tube expansion portion and the outer tube; A step of watertightly joining the inner portion and the inner cylinder over the entire circumference (e) integrally processing a pilot hole penetrating the inner cylinder and the outer cylinder in the concave portion and the side barrel portion of the inner cylinder corresponding to the concave portion (F) Using the pilot hole as a guide, part of the recess is integrally burred together with the side barrel portion of the inner cylinder corresponding to the recess to form an integral cylindrical flange portion, and at the same time The inner side of the inner cylinder and the outer side of the outer cylinder are connected to the inside of the cylindrical flange portion. Forming a through hole to be.
(G) A step of joining the inner cylinder and the outer cylinder in a watertight manner at an end of the flange portion formed by burring.

An outer cylinder, an inner cylinder inserted into the outer cylinder, and an inlet pipe and an outlet pipe that are provided in a watertight manner on the outer side of a side body portion of the outer cylinder, and the inner cylinder and the outer cylinder are A watertight structure in which the entire circumference is watertightly joined at the upper and lower parts in the axial direction to form a watertight gap between the outer cylinder and the inner cylinder, and the inlet pipe and the outlet pipe communicate with the gap. In the double pipe, a convex portion is provided on the side barrel portion of the inner cylinder so as to contact the inner periphery of the outer cylinder, and a part of the convex portion is disposed together with the side barrel portion of the outer cylinder corresponding to the convex portion. The outer side of the cylinder is bent and overlapped to form an integral cylindrical flange part on the outer side of the outer cylinder, and the inner side of the inner cylinder and the outer side of the outer cylinder are formed on the inner side of the cylindrical flange part. A communicating through hole is formed, and at the end of the flange portion, the inner cylinder and the outer cylinder are joined in a watertight manner. Above to the end portion of the flange portion provided with a transparent plate which closes the through hole, the viewing window with the heat exchange combustion cylinder, characterized in that a burner head on the inside of the inner tube.

An outer cylinder, an inner cylinder inserted into the outer cylinder, and an inlet pipe and an outlet pipe that are provided in a watertight manner on the outer side of a side body portion of the outer cylinder, and the inner cylinder and the outer cylinder are A watertight structure in which the entire circumference is watertightly joined at the upper and lower parts in the axial direction to form a watertight gap between the outer cylinder and the inner cylinder, and the inlet pipe and the outlet pipe communicate with the gap. In the double pipe, a concave portion is provided in a side barrel portion of the outer cylinder so as to contact an outer periphery of the inner cylinder, and a part of the concave portion is disposed outside the inner cylinder together with the side barrel portion of the inner cylinder corresponding to the concave portion. A through hole that bends and forms an integral cylindrical flange portion on the outer side of the inner cylinder, and communicates the inner side of the inner cylinder and the outer side of the outer cylinder to the inner side of the cylindrical flange portion. Furthermore, the inner cylinder and the outer cylinder are joined in a watertight manner at the end of the flange portion. Above to the end portion of the flange portion provided with a transparent plate which closes the through hole, the viewing window with the heat exchange combustion cylinder, characterized in that a burner head on the inside of the inner tube.