JP6132424B2

JP6132424B2 - Double pipe fitting method

Info

Publication number: JP6132424B2
Application number: JP2013038190A
Authority: JP
Inventors: 信哉小雲; 志典碓井; 鴨　和彦; 鴨　　和彦
Original assignee: Mitsubishi Heavy Industries Ltd
Current assignee: Mitsubishi Heavy Industries Ltd
Priority date: 2013-02-28
Filing date: 2013-02-28
Publication date: 2017-05-24
Anticipated expiration: 2033-02-28
Also published as: JP2014161907A

Description

本発明は、バウンダリに高い信頼性が求められるような加熱器、蒸気発生器、温水器、冷却器、復水器等のシェル・アンド・チューブ型の熱交換器に適用して好適な二重管の継手方法に関するものである。 The present invention is suitable for application to shell-and-tube heat exchangers such as heaters, steam generators, water heaters, coolers, condensers and the like that require high reliability in the boundary. it is those related to the next Tekata method of tube.

シェル・アンド・チューブ型の多管式熱交換器に用いられる二重管（伝熱管）の継手構造として、例えば特許文献１や特許文献２に開示されたものがある。 As a joint structure of a double tube (heat transfer tube) used in a shell-and-tube type multi-tube heat exchanger, there are those disclosed in Patent Document 1 and Patent Document 2, for example.

特許文献１は、図３に示すように、内管１００と外管１０１の間に空隙１０３，１０４がある２重管の継手構造において、内管１００の内側から又は開先が加工された外管１０１の開先部１０５の奥側隙間１０５ａから、レーザ光１０６によって内管１００を溶接し、その後、外管１０１の開先部１０５にリング状の溶加材１０７をはめ込み、溶接された内管１００の外側と外管１０１との間の空隙１０３，１０４に不活性ガスを流しながら、上記リング状溶加材１０７をティグ溶接で溶融させることにより、内管１００と外管１０１との間の前記空隙１０３，１０４を埋めることなく外管１０１の開先部１０５の初層溶接を行なった後、溶接ワイヤ１０８を用いて、ティグ溶接トーチ１０９により多層ティグ溶接を行うものである。 As shown in FIG. 3, Patent Document 1 discloses a double pipe joint structure in which gaps 103 and 104 are provided between an inner pipe 100 and an outer pipe 101. The inner tube 100 is welded by the laser beam 106 from the back side gap 105 a of the groove portion 105 of the tube 101, and then a ring-shaped filler material 107 is fitted into the groove portion 105 of the outer tube 101 to be welded. The ring-shaped filler metal 107 is melted by TIG welding while flowing an inert gas in the gaps 103 and 104 between the outer side of the tube 100 and the outer tube 101, so that the space between the inner tube 100 and the outer tube 101 is increased. After the first layer welding of the groove portion 105 of the outer tube 101 is performed without filling the gaps 103 and 104, multilayer TIG welding is performed by the TIG welding torch 109 using the welding wire 108.

特許文献２は、図４に示すように、内管２００と外管２０１とを有する複数の二重管構成部材２０２ａ，２０２ｂを、軸方向端部の溶接部で溶接して連結した二重管の継手構造において、上記二重管構成部材２０２ａ，２０２ｂの溶接部に、内管２００と外管２０１との間に位置して、軸方向の長さが、当該溶接部の溶接によって生じる裏波ビード幅又は溶接ビード幅の１／２以上とした溝２０３を設け、上記内管２００を当該内管２００の内側からレーザ溶接等をし（溶接部２０４ａ参照）、上記外管２０１を当該外管２０１の外側からレーザ溶接等する（溶接部２０４ｂ参照）ものである。 As shown in FIG. 4, Patent Document 2 discloses a double pipe in which a plurality of double pipe constituent members 202a and 202b each having an inner pipe 200 and an outer pipe 201 are connected by welding at a welding portion at an axial end portion. In the joint structure, the welded portion of the double pipe constituent members 202a and 202b is located between the inner tube 200 and the outer tube 201, and the axial length is a back wave generated by welding of the welded portion. A groove 203 having a bead width or a weld bead width of ½ or more is provided, the inner pipe 200 is laser welded from the inner side of the inner pipe 200 (see a welded portion 204a), and the outer pipe 201 is connected to the outer pipe. Laser welding or the like is performed from the outside of 201 (see the welded portion 204b).

特開平１０−３４３７３号公報Japanese Patent Laid-Open No. 10-34373 国際公開第２０１１/０８９９０９号パンフレットInternational Publication No. 2011/089909 Pamphlet

しかしながら、図３に示す継手構造にあっては、内管１００と外管１０１との間に空隙１０４を設けたことにより、内管１００のレーザ溶接時や外管１０１のティグ溶接時に、内管１００と外管１０１とを架橋する溶融部の発生を回避して二重バウンダリを確保した溶接が可能となるが、内管１００のレーザ溶接と外管１０１のティグ溶接との種類の異なる２工程の溶接工程を実施すると共に外管１０１の開先加工を要することから、溶接作業が煩雑となり、時間と費用が嵩むという不具合があった。 However, in the joint structure shown in FIG. 3, since the gap 104 is provided between the inner tube 100 and the outer tube 101, the inner tube can be used during laser welding of the inner tube 100 or TIG welding of the outer tube 101. It is possible to perform welding with a double boundary ensured by avoiding the occurrence of a melted portion that bridges the outer tube 101 and the outer tube 101, but two different processes of laser welding of the inner tube 100 and TIG welding of the outer tube 101 are possible. Since the welding process of the outer tube 101 is required, the welding operation is complicated, and time and cost are increased.

一方、図４に示す継手構造にあっては、二重管構成部材２０２ａ，２０２ｂの溶接部に、軸方向に所定の長さを有した溝２０３を設けたので、溶接部におけるＶノッチ（Ｖ字状の間隙）の形成を回避して短時間で溶接を行えるが、外管１０１の外側からのレーザ溶接に加えて内管１００の内側からのレーザ溶接を行う必要があることから、図４に示す継手構造と同様に、溶接作業が煩雑となると共に、内管１００の溶接には管内側からのアクセスが必要であるため、溶接ヘッドの小型化が困難であることに基因して細径の伝熱管には対応することができないという問題点があった。 On the other hand, in the joint structure shown in FIG. 4, since the groove 203 having a predetermined length in the axial direction is provided in the welded portion of the double pipe constituent members 202a and 202b, the V notch (V Although the welding can be performed in a short time while avoiding the formation of the letter-shaped gap, it is necessary to perform laser welding from the inside of the inner tube 100 in addition to laser welding from the outside of the outer tube 101. As with the joint structure shown in FIG. 1, the welding operation is complicated, and the inner tube 100 needs to be accessed from the inside of the tube for welding, so that it is difficult to reduce the size of the welding head. There was a problem that it could not cope with the heat transfer tube.

本発明は、このような実情を鑑み提案されたもので、細径の伝熱管においても二重バウンダリを確保しつつ迅速に溶接作業を行えて二重管の製作コストを削減できる二重管の継手方法を提供することを目的とする。 The present invention has been proposed in view of such a situation, and it is possible to reduce the manufacturing cost of a double pipe by reducing the manufacturing cost of the double pipe by performing a welding operation quickly while ensuring a double boundary even in a small-diameter heat transfer pipe. an object of the present invention is to provide the following Tekata method.

斯かる目的を達成するための本発明に係る二重管の継手方法は、
内管と外管とを有する複数の二重管構成部材を、軸方向端部の溶接部で溶接して連結する、軸方向の径が一定である二重管の継手方法において、
前記溶接部における前記内管と前記外管との間に、前記二重管の軸方向に部分的に空隙を設けると共に、前記内管と前記外管を同一の溶接高さとした後、前記外管の外側から前記空隙を確保しつつ前記内管と前記外管を同時にレーザ溶接するものであり、
前記レーザ溶接において、レーザビームの出力及び焦点距離の大小を調整することにより、キーホール型の溶融方式を用いる
ことを特徴とする。 In order to achieve such an object, a double pipe joint method according to the present invention comprises:
In the double pipe joint method in which the diameter in the axial direction is constant, wherein a plurality of double pipe constituent members having an inner pipe and an outer pipe are connected by welding at a weld portion at an axial end.
A gap is partially provided in the axial direction of the double pipe between the inner pipe and the outer pipe in the welded portion, and the inner pipe and the outer pipe have the same weld height, and then the outer pipe The inner tube and the outer tube are simultaneously laser welded while securing the gap from the outside of the tube,
In the laser welding , a keyhole type melting method is used by adjusting the laser beam output and the focal length .

斯かる目的を達成するための本発明に係る二重管の継手方法は、
内管と外管とを有する複数の二重管構成部材を、軸方向端部の溶接部で溶接して連結する、軸方向の径が一定である二重管の継手方法において、
前記溶接部における前記内管と前記外管との間に、前記二重管の軸方向に部分的に空隙を設けると共に、前記内管と前記外管を同一の溶接高さとした後、前記外管の外側から前記空隙を確保しつつ前記内管と前記外管を同時にレーザ溶接するものであり、
前記レーザ溶接において、レーザビームの出力及び焦点距離の大小を調整することにより、前記内管には熱伝導型の溶融方式を用い、前記外管にはキーホール型の溶融方式を用いる
ことを特徴とする。 In order to achieve such an object, a double pipe joint method according to the present invention comprises:
In the double pipe joint method in which the diameter in the axial direction is constant, wherein a plurality of double pipe constituent members having an inner pipe and an outer pipe are connected by welding at a weld portion at an axial end.
A gap is partially provided in the axial direction of the double pipe between the inner pipe and the outer pipe in the welded portion, and the inner pipe and the outer pipe have the same weld height, and then the outer pipe The inner tube and the outer tube are simultaneously laser welded while securing the gap from the outside of the tube,
Wherein in the laser welding, by adjusting the magnitude of the output and the focal length of the laser beam, using a fusion type thermal conduction type into said tube, the use of fusion type of keyhole type in the outer tube And

本発明の一実施例を示す二重管の継手方法の概念図である。It is a conceptual diagram of a relay Tekata method of the double tube showing an embodiment of the present invention.

以下、本発明に係る二重管の継手方法を実施例により図面を用いて詳細に説明する。 It will be described in detail with reference to the drawings by the joint Tekata method of the double tube according to the present invention embodiment.

図１は本発明の一実施例を示す二重管の継手方法の概念図、図２Ａはキーホール型の溶融方式の説明図、図２Ｂは熱伝導型の溶融方式とキーホール型の溶融方式を組み合わせた説明図である。 Figure 1 is an embodiment concept joint Tekata method of the double tube shown a diagram of the present invention, FIG. 2A is a schematic view for illustrating a keyhole-type fusion type, FIG. 2B is a heat conduction type melting method and keyhole type It is explanatory drawing which combined the melting system.

本実施例の二重管（伝熱管）は、バウンダリに高い信頼性が求められるような加熱器、蒸気発生器、温水器、冷却器、復水器等のシェル・アンド・チューブ型の熱交換器に適用されて好適なものである。 The double tube (heat transfer tube) of this embodiment is a shell-and-tube type heat exchange for heaters, steam generators, water heaters, coolers, condensers, etc. that require high reliability in the boundary. It is suitable to be applied to a vessel.

図１に示すように、細径（例えばφ１９ｍｍ）の二重管１０は、肉厚ｔ₁が例えば２．５ｍｍの内管１１と肉厚ｔ₂が例えば２ｍｍの外管１２とを有する複数の二重管構成部材１０ａ，１０ｂを、軸方向端部の溶接部Ｗで溶接して連結してなる。 As shown in FIG. 1, the double tube 10 having a small diameter (for example, φ19 mm) includes a plurality of inner tubes 11 having a wall thickness t ₁ of, for example, 2.5 mm and outer tubes 12 having a wall thickness t ₂ of, for example, 2 mm. The double-pipe constituent members 10a and 10b are connected by welding at the welded portion W at the end in the axial direction.

具体的には、前記溶接部Ｗにおける内管１１と外管１２との間に例えば空隙幅ｃが０．５ｍｍの空隙１３を確保して、前記外管１２の外側から内管１１と外管１２を同一の溶接高さで同時にレーザ溶接装置１４によりレーザ溶接される。尚、図中１４ａはレーザ溶接装置１４を構成する集光レンズ、１４ｂは同じくミラー、１４ｃは同じくレーザ発信器であり、１４ｄはレーザ溶接装置１４で励起されたレーザビームである。 Specifically, for example, a gap 13 having a gap width c of 0.5 mm is secured between the inner tube 11 and the outer tube 12 in the welded portion W, and the inner tube 11 and the outer tube are formed from the outside of the outer tube 12. 12 are simultaneously laser welded by the laser welding device 14 at the same welding height. In the figure, reference numeral 14a denotes a condenser lens constituting the laser welding apparatus 14, reference numeral 14b denotes a mirror, reference numeral 14c denotes a laser transmitter, and reference numeral 14d denotes a laser beam excited by the laser welding apparatus 14.

前記レーザ溶接に当たっては、図２Ａに示すように、内管１１と外管１２の両方をキーホール型（深溶込み型）の溶融方式を用いて溶接したり、図２Ｂに示すように、内管１１は熱伝導型の溶融方式を用い、外管１２はキーホール型の溶融方式を用いて溶接すると好適である。 In the laser welding, as shown in FIG. 2A, both the inner tube 11 and the outer tube 12 are welded using a keyhole type (deep penetration type) melting method, or as shown in FIG. It is preferable to weld the tube 11 using a heat conduction type melting method and the outer tube 12 using a keyhole type melting method.

即ち、図２Ａに示すように、レーザビーム１４ｄの出力を上げると共に光学系の焦点距離を長焦点距離Ｌ₁としてキーホール型の溶融方式（キーホール部１５ａ，１５ｂ参照）で溶接を行えば、外管１２も内管１１も溶融できて同時溶接が可能となるのである。但し、むやみにレーザビーム１４ｄの出力を上げると、内管１１を溶融する際に内面に溶融金属が飛び散ってスパッタＳが発生し、内管１１の内面に付着したり、異物となるので、この場合は、内管１１の内面側にスパッタＳの回収処理をする手段を設ける必要がある。 That is, as shown in FIG. 2A, the laser beam 14d keyhole type melting method the focal length of the optical system as a long focal length L ₁ along with increasing the output of the (keyhole portions 15a, 15b reference) by performing welding in, Both the outer tube 12 and the inner tube 11 can be melted to enable simultaneous welding. However, if the output of the laser beam 14d is increased unnecessarily, the molten metal scatters on the inner surface when the inner tube 11 is melted, and spatter S is generated and adheres to the inner surface of the inner tube 11 or becomes a foreign substance. In this case, it is necessary to provide means for collecting the sputter S on the inner surface side of the inner tube 11.

一方、図２Ｂに示すように、レーザビーム１４ｄの出力を上げると共に光学系の焦点距離を短焦点距離Ｌ₂（Ｌ₁>Ｌ₂）とすることで、内管１１は熱伝導型の溶融方式（熱伝導溶融部１６参照）を用い、外管１２はキーホール型の溶融方式（キーホール部１５ａ参照）を用いて外管１２と内管１１の同時溶接が可能となる。即ち、内管１１はレーザビーム１４ｄがぼける（パワー密度が低下する）ため、キーホール型ではなく熱伝導型の溶融方式となり、その内面へのスパッタＳ（図２Ａ参照）の発生を抑制することができるのである。 On the other hand, as shown in FIG. 2B, by increasing the output of the laser beam 14d and setting the focal length of the optical system to a short focal length L ₂ (L ₁ > L ₂ ), the inner tube 11 is a heat conduction type melting method. The outer tube 12 can be welded simultaneously to the outer tube 12 and the inner tube 11 using a keyhole type melting method (see the keyhole portion 15a). That is, since the laser beam 14d is blurred (the power density is reduced), the inner tube 11 is a heat conduction type melting method instead of a keyhole type, and suppresses the generation of spatter S (see FIG. 2A) on the inner surface thereof. Can do it.

このようにして、本実施例では、レーザビーム１４ｄの出力や光学系の焦点距離の条件を最適化することにより、レーザ溶接装置１４により外管１２の外側から外管１２と内管１１における二重バウンダリを確報した同時溶接がスパッタの飛散を抑制しつつ可能となる。 In this way, in the present embodiment, by optimizing the conditions of the output of the laser beam 14d and the focal length of the optical system, the laser welding device 14 uses the two in the outer tube 12 and the inner tube 11 from the outside of the outer tube 12. Simultaneous welding that reports the heavy boundary is possible while suppressing spatter scattering.

これにより、細径の二重管１０においても迅速に溶接作業を行えて二重管１０の製作コストを削減できる。 Thereby, even in the small-diameter double pipe 10, the welding operation can be performed quickly, and the manufacturing cost of the double pipe 10 can be reduced.

尚、本発明は上記実施例に限定されず、本発明の要旨を逸脱しない範囲内で各種変更が可能であることは言うまでもない。例えば、空隙１３は内管１１外面と外管１２内面との両方に溝加工することで形成される例を示したが、何れか一方に溝加工して形成しても良い。また、内管１１と外管１２とが密着した例を示したが、内管と外管とが直接接触しない（組網線やスペーサが挿入される隙間が形成されるか全長に亘って溝が形成される）二重管にも本発明は適用できる。 Needless to say, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. For example, the gap 13 is formed by grooving both the outer surface of the inner tube 11 and the inner surface of the outer tube 12, but may be formed by grooving either one. Moreover, although the inner tube 11 and the outer tube 12 are shown in close contact with each other, the inner tube and the outer tube are not in direct contact with each other (a gap in which a braided wire or spacer is inserted is formed or a groove is formed over the entire length The present invention can also be applied to a double tube.

本発明に係る二重管の継手方法は、二重バウンダリを確保しつつ迅速に溶接作業を行えて信頼性が高まるので、バウンダリに高い信頼性が求められるような加熱器、蒸気発生器、温水器、冷却器、復水器等のシェル・アンド・チューブ型の熱交換器に用いて好適である。 Splicing Tekata method of the double tube according to the present invention, since the reliability is increased by performing the rapid welding operation while ensuring a double boundary, heaters such as high reliability to the boundary is determined, the steam generator It is suitable for use in shell-and-tube heat exchangers such as water heaters, coolers, condensers and the like.

１０二重管（伝熱管）
１０ａ，１０ｂ二重管構成部材
１１内管
１２外管
１３空隙
１４レーザ溶接装置
１４ａ集光レンズ
１４ｂミラー
１４ｃレーザ発信器
１４ｄレーザビーム
１５ａ，１５ｂキーホール部
１６熱伝導型溶融部
Ｃ空隙幅
Ｌ₁ 長焦点距離
Ｌ₂ 短焦点距離
Ｓスパッタ
ｔ₁内管の肉厚
ｔ₂外管の肉厚
Ｗ溶接部 10 Double tube (heat transfer tube)
10a, 10b Double tube component 11 Inner tube 12 Outer tube 13 Air gap 14 Laser welding device 14a Condensing lens 14b Mirror 14c Laser transmitter 14d Laser beam 15a, 15b Keyhole portion 16 Heat conduction type melting portion C Air gap width L ₁ Long focal length L ₂ Short focal length S Spatter t ₁ Inner tube thickness t ₂ Outer tube thickness W Weld

Claims

In the double pipe joint method in which the diameter in the axial direction is constant, wherein a plurality of double pipe constituent members having an inner pipe and an outer pipe are connected by welding at a weld portion at an axial end.
A gap is partially provided in the axial direction of the double pipe between the inner pipe and the outer pipe in the welded portion, and the inner pipe and the outer pipe have the same weld height, and then the outer pipe The inner tube and the outer tube are simultaneously laser welded while securing the gap from the outside of the tube,
In the laser welding, by adjusting the magnitude of the output and the focal length of the laser beam, fitting method of the double tube you characterized by using the melt method of keyhole type.

In the double pipe joint method in which the diameter in the axial direction is constant, wherein a plurality of double pipe constituent members having an inner pipe and an outer pipe are connected by welding at a weld portion at an axial end.
A gap is partially provided in the axial direction of the double pipe between the inner pipe and the outer pipe in the welded portion, and the inner pipe and the outer pipe have the same weld height, and then the outer pipe The inner tube and the outer tube are simultaneously laser welded while securing the gap from the outside of the tube,
Wherein in the laser welding, by adjusting the magnitude of the output and the focal length of the laser beam, using a fusion type thermal conduction type into said tube, the use of fusion type of keyhole type in the outer tube joint method of the double tube shall be the.