JP5083824B2

JP5083824B2 - Gas piping repair method and repair structure

Info

Publication number: JP5083824B2
Application number: JP2008107995A
Authority: JP
Inventors: 栄司鷹野; 純一村田; 利夫後藤
Original assignee: Nippon Steel Corp
Current assignee: Nippon Steel Corp
Priority date: 2008-04-17
Filing date: 2008-04-17
Publication date: 2012-11-28
Anticipated expiration: 2028-04-17
Also published as: JP2009257492A

Description

本発明は、腐食、磨耗等によって管外周面に損傷部が発生したガス配管を補修する方法に関し、特に、コークス炉における配管のように内圧が負圧とされたガス配管を補修するのに好適なガス配管の補修方法とこれに用いられる補修構造に関する。 The present invention relates to a method for repairing a gas pipe in which a damaged portion is generated on the outer peripheral surface of the pipe due to corrosion, wear, etc., and particularly suitable for repairing a gas pipe having a negative internal pressure such as a pipe in a coke oven. The present invention relates to a repair method for a gas pipe and a repair structure used therefor.

ガスや水、油等の各種流体を移送するために用いられる配管は、設置後の年数経過に伴い、その内周面や外周面において磨耗や腐食が発生し、これによって配管の肉厚が減肉したり、配管に貫通孔が開口されたりしてしまい、配管に損傷部が形成されることになる。このような損傷部は、腐食環境が劣悪な屋外に設置された配管に発生し易く、配管を固定する固定金具の周囲においては、雨水等が溜まり易いため特に発生し易い。 Pipes used to transport various fluids such as gas, water, oil, etc., wear and corrode on the inner and outer peripheral surfaces over the years after installation, which reduces the wall thickness of the pipes. If it becomes meat or a through hole is opened in the pipe, a damaged portion is formed in the pipe. Such a damaged portion is likely to occur in a pipe installed outdoors where the corrosive environment is poor, and is particularly likely to occur because rainwater or the like tends to accumulate around a fixing bracket for fixing the pipe.

このような損傷部が形成された配管の補修方法としては、例えば、配管の外径より大きい内径寸法を有する筒状の型枠を利用して配管を補修する方法が提案されている（特許文献１参照。）。この方法においては、補修部周囲の配管全周を覆うように、二つ割又は三つ割等の複数に分割された型枠を取り付け、この型枠内に液状の硬化性樹脂を注入することによって行なわれる。この場合において、複数に分割された型枠は、配管外周に仮固定した後、複数の型枠をゴム等の紐状のパッキングを巻き付けることによって固定される。 As a method for repairing a pipe in which such a damaged portion is formed, for example, a method of repairing a pipe using a cylindrical formwork having an inner diameter larger than the outer diameter of the pipe has been proposed (Patent Document). 1). In this method, a mold divided into a plurality of parts such as two or three is attached so as to cover the entire circumference of the pipe around the repaired part, and a liquid curable resin is injected into the mold. Is done by. In this case, the plurality of molds are temporarily fixed to the outer periphery of the pipe and then fixed by winding the plurality of molds around a string-like packing such as rubber.

また、この他の配管の補修方法としては、例えば、半割筒状の二つのクランプ材を利用する補修方法が提案されている（特許文献２参照。）。この二つのクランプ材は、その軸方向の両側の内周面に半割リング状のシール材が嵌装されており、補修部周囲の配管外周面を覆うように配置した際に、このシール材が配管外周に密着することになる。これによってクランプ材と補修部周囲の配管外周面との間の内部空間の密閉性が確保され、この空間内に対して充填材が充填され、配管内の流体の漏洩等が防止される。 As another pipe repair method, for example, a repair method using two half-cylinder-shaped clamp members has been proposed (see Patent Document 2). These two clamp members are fitted with half-ring-shaped seals on the inner peripheral surfaces on both sides in the axial direction. When these two clamp members are arranged so as to cover the outer peripheral surfaces of the pipes around the repair parts, Will adhere to the outer periphery of the pipe. As a result, the internal space between the clamp member and the outer peripheral surface of the pipe around the repair portion is secured, and the inside of this space is filled with the filler to prevent leakage of fluid in the pipe.

また、この他にも、配管の外周面に対して、その外周面に沿った形状の補強板を当てがい、補強板の周囲を溶接することによって固定し、これによって、配管内部の流体の漏洩を防止する配管の補修方法も提案されている（特許文献３参照。）。
特開平０１−２１０６８８号公報特開平０７−１５１２９２号公報特開２００３−８０３９２号公報 In addition to this, a reinforcing plate having a shape along the outer peripheral surface is applied to the outer peripheral surface of the pipe, and the periphery of the reinforcing plate is fixed by welding, thereby leaking fluid inside the pipe. A pipe repairing method for preventing this has been proposed (see Patent Document 3).
Japanese Patent Laid-Open No. 01-210688 Japanese Patent Laid-Open No. 07-151292 JP 2003-80392 A

ところで、高炉や転炉、コークス炉等においては、副時的な生成物としてコークス炉ガス等の各種ガスが生成される。このコークス炉ガスは、例えば、コークス炉からの流出後に精製することによって、燃料ガスとして再利用することができる。このため、コークス炉から流出するコークス炉ガスは、ガスブロワー等によって炉内からドライメーン、ガス配管を介して吸引してガス精製設備にまで移送している。この場合において、ドライメーンから誘引ブロワーまでの区間におけるガス配管の内圧は、負圧とされていることになる。 By the way, in blast furnaces, converters, coke ovens, and the like, various gases such as coke oven gas are generated as secondary products. This coke oven gas can be reused as a fuel gas, for example, by purifying it after flowing out of the coke oven. For this reason, the coke oven gas flowing out of the coke oven is sucked from the inside of the furnace through a dry main and gas piping by a gas blower or the like and transferred to a gas purification facility. In this case, the internal pressure of the gas pipe in the section from the dry main to the induction blower is a negative pressure.

ここで、このような負圧環境下のガス配管を補修する際に、上述の特許文献１や特許文献２に記載の開示技術を利用すると、何れの技術も型枠やクランプ材を介してガス配管に対して管外から管内に向けて応力を負荷することになるため、肉厚が減肉されて部材耐力が脆弱化されたガス配管に対して過剰に応力が負荷され、ガス配管の損傷部が更に損壊する恐れがあり、好ましくない。 Here, when repairing the gas piping under such a negative pressure environment, if the disclosed technologies described in Patent Document 1 and Patent Document 2 described above are used, any of the technologies is performed through a mold or a clamp material. Since stress is applied to the pipe from the outside to the inside of the pipe, excessive stress is applied to the gas pipe whose wall thickness has been reduced and the material strength has been weakened, resulting in damage to the gas pipe. The part may be further damaged, which is not preferable.

また、上述の特許文献３に記載の開示技術は、その補修工程において配管に対して溶接を施しているが、配管の内圧が高圧、即ち、正圧とされている。内圧が正圧の配管に対して溶接を施す場合、溶接熱によって管が破孔したとしても、管内の流体が管内から管外に噴出しているため、溶接による火種がこの噴出している流体に着火するのみで、管内に急激に伝達する可能性が少ないと考えられる。しかしながら、内圧が負圧の配管に対して溶接を施す場合、破孔時において、溶接による火種や管周囲の空気が管内に吸入され、管内の流体が揮発性を有していると大規模な爆発事故を招く危険性がある。 Moreover, although the disclosed technique of the above-mentioned patent document 3 welds with respect to piping in the repair process, the internal pressure of piping is high pressure, ie, a positive pressure. When welding pipes with positive internal pressure, even if the pipe breaks due to welding heat, the fluid in the pipe is ejected from the inside of the pipe to the outside of the pipe. It is considered that there is little possibility of rapid transmission into the pipe just by igniting the. However, when welding is performed on a pipe with a negative internal pressure, the fire type and air around the pipe are sucked into the pipe at the time of puncture, and the fluid in the pipe is volatile. Risk of explosion.

このため、内圧が負圧の配管に対して溶接による補修を施す際には、溶接によって配管に破孔を起こさせずに溶接をする必要があるが、配管の内圧が正圧の場合と負圧の場合とで溶接時の熱影響が同様であるか否かは明確にされていなかったため、内圧が負圧のガス配管に対して、溶接を利用して補修を行なう方法は積極的に利用されていなかった。 For this reason, when repairing a pipe with negative internal pressure by welding, it is necessary to weld without causing a hole in the pipe by welding. It was not clarified whether the thermal effect during welding was the same as in the case of pressure, so the method of repairing by using welding for gas pipes with negative internal pressure was actively used. Was not.

もちろん、損傷部を有するガス配管そのものを交換することによって、配管を健全なものとする技術の適用も考えられる。しかし、コークス炉の場合、数十基の炉設備が２４時間に亘って同時に稼動しており、ガス配管の交換のためにガス流通を停止しようとすると、数十基の炉設備を同時に停止する必要が生じるため、炉設備の運用上この方法も好ましくなかった。 Of course, it is also conceivable to apply a technique for making a pipe sound by replacing the gas pipe itself having a damaged portion. However, in the case of a coke oven, dozens of furnace facilities have been operating simultaneously for 24 hours, and when trying to stop gas flow for gas pipe replacement, dozens of furnace facilities are simultaneously stopped. This method is also not preferable for the operation of the furnace equipment because of the necessity.

このため、従来においては、管外からの過剰な圧力や熱を与えることなく配管補修を行なうため、ガス配管外周の損傷部に対してパテのような硬化性充填材を塗布するといった方法を用いていた。しかしながら、例えばガス配管の固定金具周囲に発生した損傷部を補修する場合等は、損傷部の損傷の度合いによっては、硬化性充填材を塗布する際に損傷部そのものが損壊してしまう可能性があり、損傷部そのものに接触することなく補修を行なうことが可能な補修方法が望まれていた。 For this reason, conventionally, in order to repair the pipe without applying excessive pressure or heat from the outside of the pipe, a method of applying a curable filler such as putty to the damaged part of the outer circumference of the gas pipe is used. It was. However, for example, when repairing a damaged part around the gas pipe fixing bracket, the damaged part itself may be damaged when applying the curable filler depending on the degree of damage of the damaged part. There has been a demand for a repair method capable of repairing without touching the damaged part itself.

そこで、本発明は、上述した問題点に鑑みて案出されたものであり、その目的とするところは、内圧が負圧とされたガス配管に対して溶接によって補修を行なうにあたり、溶接による配管の破孔を確実に防止可能なガス配管の補修方法とこれに用いられる補修構造を提供することにある。 Therefore, the present invention has been devised in view of the above-described problems, and the object of the present invention is to perform piping repair by welding on a gas piping whose internal pressure is negative. Another object of the present invention is to provide a gas pipe repairing method and a repairing structure used therefor, which can surely prevent a hole from being broken.

本発明者は、上述した課題を解決するために、損傷部から管軸方向の両側に位置し、ガス配管の全周における残存肉厚が３．２ｍｍ以上とされた部位に対して、その全周に沿ってリング状部材を周設し、上記損傷部の管軸方向の両側に周設した上記リング状部材の外周の全周に沿って筒状部材を当該損傷部を跨るように周設し、上記リング状部材の側面、上記筒状部材の内周面並びに上記配管の外周面によって包囲された閉空間内に不活性ガスを封入することを特徴とするガス配管の補修方法を発明した。 In order to solve the above-mentioned problems, the inventor is located on both sides of the pipe axis direction from the damaged part, and the entire thickness of the gas pipe around the circumference is 3.2 mm or more. A ring-shaped member is provided along the circumference, and the tubular member is provided so as to straddle the damaged portion along the entire outer circumference of the ring-shaped member provided on both sides of the damaged portion in the tube axis direction. And inventing a gas pipe repairing method, wherein an inert gas is sealed in a closed space surrounded by a side surface of the ring-shaped member, an inner peripheral surface of the cylindrical member, and an outer peripheral surface of the pipe. .

即ち、本願請求項１に係るガス配管の補修方法は、内圧が負圧とされたガス配管の外周面に形成された損傷部を補修するガス配管の補修方法において、上記損傷部から管軸方向の両側に位置し、ガス配管の全周における残存肉厚が３．２ｍｍ以上とされた部位に対して、その全周に沿ってリング状部材を溶接により周設し、上記損傷部の管軸方向の両側に周設した上記リング状部材の外周の全周に沿って筒状部材を当該損傷部を跨るように周設し、上記リング状部材の側面、上記筒状部材の内周面並びに上記配管の外周面によって包囲された閉空間内に不活性ガスを封入することを特徴とする。 That is, the gas pipe repairing method according to claim 1 of the present application is a gas pipe repairing method for repairing a damaged part formed on the outer peripheral surface of the gas pipe having a negative internal pressure. A ring-shaped member is provided by welding along the entire circumference of the portion located on both sides of the gas pipe and the remaining thickness of the entire circumference of the gas pipe is 3.2 mm or more. A cylindrical member is provided so as to straddle the damaged portion along the entire outer circumference of the ring-shaped member provided on both sides in the direction, and the side surface of the ring-shaped member, the inner peripheral surface of the cylindrical member, and An inert gas is sealed in a closed space surrounded by the outer peripheral surface of the pipe.

本願請求項２に係る発明は、本願請求項１に係る発明において、ガス配管の全周における残存肉厚が４．５ｍｍ以上とされた部位に対して、上記リング状部材を溶接により周設することを特徴とする。 The invention according to claim 2 of the present application is the invention according to claim 1 of the present application, wherein the ring-shaped member is circumferentially provided by welding to a portion where the remaining thickness of the entire circumference of the gas pipe is 4.5 mm or more. It is characterized by that.

本願請求項３に係るガス配管の補修構造は、内圧が負圧とされたガス配管の外周面に形成された損傷部を補修するガス配管の補修構造において、上記損傷部から管軸方向の両側に位置し、ガス配管の全周における残存肉厚が３．２ｍｍ以上とされた部位に対して、その全周に沿ってリング状部材が溶接により周設され、上記損傷部の管軸方向の両側に周設した上記リング状部材の外周の全周に沿って筒状部材が当該損傷部を跨るように周設され、上記リング状部材の側面、上記筒状部材の内周面並びに上記配管の外周面によって包囲された閉空間内に不活性ガスが封入されていることを特徴とする。 The gas pipe repair structure according to claim 3 of the present application is a gas pipe repair structure for repairing a damaged portion formed on the outer peripheral surface of the gas pipe whose internal pressure is a negative pressure. A ring-shaped member is provided by welding along the entire circumference of the portion where the remaining thickness of the gas pipe is 3.2 mm or more around the entire circumference of the gas pipe. A cylindrical member is provided so as to straddle the damaged portion along the entire outer circumference of the ring-shaped member provided on both sides, and the side surface of the ring-shaped member, the inner peripheral surface of the cylindrical member, and the pipe An inert gas is enclosed in a closed space surrounded by the outer peripheral surface of the gas.

本願請求項４に係る発明は、本願請求項３に係る発明において、上記リング状部材は、ガス配管の全周における残存肉厚が４．５ｍｍ以上とされた部位に対して周設されていることを特徴とする。 The invention according to claim 4 of the present application is the invention according to claim 3 of the present application, wherein the ring-shaped member is provided around a portion where the remaining thickness of the entire circumference of the gas pipe is 4.5 mm or more. It is characterized by that.

本発明を適用した配管の補修方法によって、従来において溶接による補修が困難であった、内圧が負圧とされた配管に対してでも、破孔を生じさせることなく溶接による補修を施すことが可能となり、これを利用して、損傷部３に対して接触等することなく補修を完了させることができる。特に、閉空間２８を形成しているリング状部材２１、筒状部材２３並びに配管１は、溶接することによって互いに接合されているため、閉空間をシーリング材やパッキン等によって形成した場合と比較して閉空間２８内の密閉性が良好に保たれており、これに伴い、その内部に封入された不活性ガスの漏洩を確実に防止可能となる。このような不活性ガスを封入した閉空間に配置される損傷部は、腐食が非常に進行しにくく、パテのような硬化性充填材を塗布して補修を施した場合と比較して、耐腐食性能が大きく向上していることになる。また、本発明を適用した配管の補修方法によれば、配管１の切断等することなく補修が完了するため、配管内のガス流通を停止することなく補修を確実に行なうことができる。 By the pipe repair method to which the present invention is applied, it is possible to perform repair by welding without causing a broken hole even for pipes in which the internal pressure has been negative, which has been difficult to repair by welding in the past. Thus, using this, the repair can be completed without contacting the damaged portion 3 or the like. In particular, since the ring-shaped member 21, the cylindrical member 23, and the pipe 1 that form the closed space 28 are joined to each other by welding, compared with the case where the closed space is formed by a sealing material, packing, or the like. Thus, the hermeticity in the closed space 28 is maintained well, and accordingly, it is possible to reliably prevent the leakage of the inert gas sealed therein. Damaged parts placed in a closed space filled with such an inert gas are less prone to corrosion, and are more resistant to damage when applied by applying a curable filler such as putty. Corrosion performance is greatly improved. In addition, according to the pipe repair method to which the present invention is applied, the repair is completed without cutting the pipe 1 or the like, so that the repair can be reliably performed without stopping the gas flow in the pipe.

以下、本発明を実施するための最良の形態として、外周面に損傷部が形成されたコークス炉のガス配管を補修するためのガス配管の補修方法について、図面を参照しながら詳細に説明する。 Hereinafter, as a best mode for carrying out the present invention, a gas pipe repair method for repairing a gas pipe of a coke oven having a damaged portion formed on the outer peripheral surface will be described in detail with reference to the drawings.

図１は、本発明の適用の対象となる配管１が設置されているコークス炉５の概略配管図である。コークス炉５においては、複数の炭化室を有する炉本体５１と、炉本体５１内の各炭化室内で発生したコークス炉ガスを炉本体５１単位で収集するドライメーン５３とが複数組に亘って設置されている。各ドライメーン５３によって収集されたコークス炉ガスは、配管１のガス移送経路の途中に設置されたガスブロワー５７によって吸引された後、ガス精製設備５９に対して圧送されて、燃料ガスとして使用可能となる。ドライメーン５３とガスブロワー５７との間のガス移送経路においては、通常、コークス炉ガスを冷却するためのプライマリクーラー５５が設置されている。 FIG. 1 is a schematic piping diagram of a coke oven 5 in which a pipe 1 to which the present invention is applied is installed. In the coke oven 5, a plurality of sets of furnace bodies 51 having a plurality of carbonization chambers and dry mains 53 for collecting the coke oven gas generated in each carbonization chamber in the furnace body 51 in units of the furnace bodies 51 are installed. Has been. The coke oven gas collected by each dry main 53 is sucked by the gas blower 57 installed in the middle of the gas transfer path of the pipe 1 and then pumped to the gas purification equipment 59 to be used as fuel gas. It becomes. In the gas transfer path between the dry main 53 and the gas blower 57, a primary cooler 55 for cooling the coke oven gas is usually installed.

配管１は、コークス炉５における各種設備の内壁、外壁の天井壁、側壁、床壁に対して、図２に示すような配管固定具７によって固定されている。この配管固定具７は、床壁に設置され、配管１をその下部から支持固定する架台１０としての態様の他に、各種設備の側壁、天井壁に設置され、配管１をその側壁、天井壁に固定する態様によって具体化されるものである。この配管固定具７は、配管１を各種設備の外壁等に固定可能なものであれば、特にその構成を問うものではない。 The pipe 1 is fixed to the inner wall of various facilities in the coke oven 5, the ceiling wall, the side wall, and the floor wall of the outer wall by a pipe fixing tool 7 as shown in FIG. This pipe fixing tool 7 is installed on the floor wall, and is installed on the side wall and ceiling wall of various facilities in addition to the form as a gantry 10 that supports and fixes the pipe 1 from the lower part thereof. It is actualized by the aspect fixed to. The pipe fixture 7 is not particularly limited as long as the pipe 1 can be fixed to the outer wall of various facilities.

本発明の適用の対象となる配管１は、その内圧が負圧とされたものである。コークス炉５においては、ドライメーン５３からガスブロワー５７までの範囲に設置された配管が、その内部の圧力が負圧とされている。この区間における配管１内の圧力は、一般には、−６．８６４５〜−３．９２２７ｋＰａ（−７００〜−４００ｍｍＡｑ）とされている。 The pipe 1 to which the present invention is applied has a negative internal pressure. In the coke oven 5, the pipe installed in the range from the dry main 53 to the gas blower 57 has a negative pressure inside. The pressure in the pipe 1 in this section is generally set to −6.8645 to −3.9227 kPa (−700 to −400 mmAq).

このような区間に設置された配管１は、配管１周囲の腐食性のあるガス雰囲気や、プライマリクーラー５５においてコークス炉ガスの冷却に用いられる海水等の影響によって、特に腐食が発生し易い環境下にある。特に、配管１と配管固定具７とが接触している部位は、水滴等が溜まり易く、そこから腐食が顕著に発生してしまう。以下、図２に示すような、架台１０としての配管固定具７によって支持固定されている配管に対して補修を行う場合を例に、配管の補修方法について説明する。 The pipe 1 installed in such a section is in an environment where corrosion is particularly likely to occur due to the corrosive gas atmosphere around the pipe 1 and seawater used for cooling the coke oven gas in the primary cooler 55. It is in. In particular, at the portion where the pipe 1 and the pipe fixture 7 are in contact with each other, water droplets or the like are likely to accumulate, and corrosion is prominently generated therefrom. Hereinafter, the pipe repairing method will be described by taking as an example the case of repairing the pipe supported and fixed by the pipe fixture 7 as the gantry 10 as shown in FIG.

配管１は、コークス炉ガスのような流体を移送するために用いられる中空断面の管体である。この配管１の全肉厚は、後述のように配管１の何れかの部位における全周の残存肉厚として３．２ｍｍ以上必要とされるため、少なくとも３．２ｍｍ以上の全肉厚を有する配管が対象となる。 The pipe 1 is a hollow cross-section tube used for transferring a fluid such as coke oven gas. Since the total thickness of the pipe 1 is required to be 3.2 mm or more as the remaining thickness of the entire circumference in any part of the pipe 1 as described later, the pipe having a total thickness of at least 3.2 mm or more. Is the target.

図２に示すように、配管１は、配管１を下部から支持するための架台１０によって支持固定されている。架台１０は、配管１を載置可能なテーパ形状が上辺に形成された受け部１１と、受け部１１を床壁９上で支持する脚部１３と、受け部１１上で支持された配管１が左右方向に抜け落ちるのを防止し、受け部１１上に固定するためのバンド部１５とから構成されている。バンド部１５は、その内周面において配管１と当接可能なテーパ形状が形成されている。受け部１１上に載置された配管１は、受け部１１の径方向両端部に設けられた突出部１１aに対して、バンド部１５の径方向両端部に設けられた突出部１５aを当接させた状態で、両突出部１１ａ、１５ａをボルト結合することによって、受け部１１上で支持固定されている。 As shown in FIG. 2, the pipe 1 is supported and fixed by a gantry 10 for supporting the pipe 1 from below. The gantry 10 includes a receiving part 11 having a tapered shape on the upper side on which the pipe 1 can be placed, a leg part 13 that supports the receiving part 11 on the floor wall 9, and a pipe 1 that is supported on the receiving part 11. Is configured to include a band portion 15 for preventing it from falling off in the left-right direction and fixing it on the receiving portion 11. The band portion 15 is formed with a tapered shape capable of coming into contact with the pipe 1 on the inner peripheral surface thereof. The pipe 1 placed on the receiving portion 11 abuts the protruding portions 11 a provided at both radial ends of the band portion 15 against the protruding portions 11 a provided at both radial ends of the receiving portion 11. In this state, both the protruding portions 11a and 15a are bolted and supported and fixed on the receiving portion 11.

この架台１０上に支持されている配管１の受け部１１やバンド部１５近傍においては、腐食が特に発生し易くなっており、図２に示すような損傷部３が形成されることがある。この損傷部３は、配管の外周面や内周面が腐食、磨耗等によって減肉されたり、孔が開口されたりした配管の一部のことをいう。 In the vicinity of the receiving portion 11 and the band portion 15 of the pipe 1 supported on the gantry 10, corrosion is particularly likely to occur, and a damaged portion 3 as shown in FIG. 2 may be formed. The damaged part 3 refers to a part of the pipe in which the outer peripheral surface and the inner peripheral surface of the pipe are thinned due to corrosion, wear or the like, or a hole is opened.

図３は、このような架台１０上に支持されている配管１に対して、本発明の補修方法を施した後の状態を示す図である。 FIG. 3 is a view showing a state after the repair method of the present invention is applied to the pipe 1 supported on the gantry 10.

補修後において損傷部３が形成されている配管１には、その損傷部３を補修する構造体としての中空ボックス体３１が取り付けられる。中空ボックス体３１は、損傷部３に対して管軸方向の両側に位置する所定の部位の全周に沿って溶接により周設されたリング状部材２１と、損傷部３を跨るようにして、損傷部３の管軸方向の両側に周設したリング状部材２１の外周の全周に沿って周設された筒状部材２３とから構成される。なお、リング状部材２１が取り付けられる配管１の所定の部位とは、後述の条件に基づいて定まるものであり、以下この所定の部位を取付部４１という。 A hollow box body 31 as a structure for repairing the damaged portion 3 is attached to the pipe 1 in which the damaged portion 3 is formed after the repair. The hollow box body 31 spans the damaged portion 3 and the ring-shaped member 21 provided by welding along the entire circumference of a predetermined portion located on both sides in the tube axis direction with respect to the damaged portion 3, It is comprised from the cylindrical member 23 provided along the perimeter of the outer periphery of the ring-shaped member 21 provided in the both sides of the pipe-axis direction of the damage part 3. As shown in FIG. In addition, the predetermined part of the pipe 1 to which the ring-shaped member 21 is attached is determined based on conditions described later. Hereinafter, the predetermined part is referred to as an attachment part 41.

リング状部材２１は、図４（a）に示すように、管軸方向に向けて所定の厚みを有し、半割リング状の形状からなる二つの分割リング状部材２２によって構成されている。各分割リング状部材２２の内周面２２ａは、周設しようとする配管１の取付部４１の外周面４１ａに沿って当接可能な形状に形成されている。各分割リング状部材２２は、配管１の取付部４１の外周面４１ａに沿って配置した場合に、一つのリング状部材２１となるように、一つのリング形状を複数個に亘って径方向に分割した形状で構成されており、その分割個数は特に問わない。このリング状部材２１は、配管１に対して溶接可能となるように鋼材によって構成されるものである。 As shown in FIG. 4A, the ring-shaped member 21 is configured by two divided ring-shaped members 22 having a predetermined thickness in the tube axis direction and having a half-ring shape. The inner peripheral surface 22a of each divided ring-shaped member 22 is formed in a shape that can contact along the outer peripheral surface 41a of the attachment portion 41 of the pipe 1 to be provided around. When each divided ring-shaped member 22 is disposed along the outer peripheral surface 41a of the attachment portion 41 of the pipe 1, a plurality of one ring shape is radially formed so as to become one ring-shaped member 21. It consists of divided shapes, and the number of divisions is not particularly limited. The ring-shaped member 21 is made of a steel material so that it can be welded to the pipe 1.

筒状部材２３は、図４（ｂ）に示すように、管軸方向に向けて所定の長さを有し、半割筒状の形状からなる上部分割筒状部材２４と、半割筒状の形状を更に管軸方向に向けて分割した形状からなる下部分割筒状部材２５によって構成されている。上部分割筒状部材２４や下部分割筒状部材２５は、鋼板を屈曲等して成形されるものである。上部分割筒状部材２４、下部分割筒状部材２５の内周面２４ａ、２５ａは、周設しようとする分割リング状部材２２の外周面２２ｂに沿って当接可能な形状に形成されている。上部分割筒状部材２４、下部分割筒状部材２５は、分割リング状部材２２の外周面２２ｂに沿って配置した場合に、一つの筒状部材２３となるように、一つの筒形状を複数個に亘って径方向に分割した形状で構成されており、その分割個数は、特に問わない。 As shown in FIG. 4 (b), the cylindrical member 23 has an upper divided cylindrical member 24 having a predetermined length in the tube axis direction and having a half-cylindrical shape, and a half-cylindrical shape. Is formed by a lower divided cylindrical member 25 having a shape obtained by further dividing the shape of the tube toward the tube axis direction. The upper divided cylindrical member 24 and the lower divided cylindrical member 25 are formed by bending a steel plate. The inner peripheral surfaces 24a and 25a of the upper divided cylindrical member 24 and the lower divided cylindrical member 25 are formed in a shape that can be contacted along the outer peripheral surface 22b of the divided ring-shaped member 22 to be provided. When the upper divided cylindrical member 24 and the lower divided cylindrical member 25 are arranged along the outer peripheral surface 22b of the divided ring-shaped member 22, a plurality of one cylindrical shape is formed so as to become one cylindrical member 23. The number of divisions is not particularly limited.

リング状部材２１は、配管１の取付部４１の外周面４１ａに対して部分溶け込み溶接又は隅肉溶接によって接合されており、筒状部材２３は、リング状部材２１の外周面に対して部分溶け込み溶接、隅肉溶接に限らず、完全溶け込み溶接によっても接合される。 The ring-shaped member 21 is joined to the outer peripheral surface 41 a of the attachment portion 41 of the pipe 1 by partial penetration welding or fillet welding, and the cylindrical member 23 is partially penetrated to the outer peripheral surface of the ring-shaped member 21. Joining is not limited to welding and fillet welding, but also by full penetration welding.

下部分割筒状部材２５には、分割リング状部材２２の外周面２２ｂに沿って配置した場合に、架台１０の脚部１３を露出可能となるように、その一部において径方向に沿って開口された切欠２６が形成されている。 The lower divided cylindrical member 25 has an opening along the radial direction at a part thereof so that the leg portion 13 of the gantry 10 can be exposed when arranged along the outer peripheral surface 22b of the divided ring-shaped member 22. A cut-out 26 is formed.

損傷部３を含むその周囲の配管１と、架台１０の受け部１１やバンド部１５、脚部１３の上部は、リング状部材２１の側壁、筒状部材２３の内周面並びに損傷部３近傍の配管１外周面によって包囲された閉空間２８内に配置されるようになっており、リング状部材２１及び筒状部材２３がなす中空ボックス体３１によって覆われるようになっている。 The surrounding piping 1 including the damaged portion 3, the receiving portion 11 of the gantry 10, the band portion 15, and the upper portion of the leg portion 13 are the side wall of the ring-shaped member 21, the inner peripheral surface of the tubular member 23, and the vicinity of the damaged portion 3. It is arranged in a closed space 28 surrounded by the outer peripheral surface of the pipe 1 and is covered by a hollow box body 31 formed by the ring-shaped member 21 and the cylindrical member 23.

筒状部材２３には、その一部において、閉空間２８内に気体等を流出入可能な挿通管２７が設けられており、この挿通管２７の一端側の開口は、蓋部材２９によって閉塞されている。 A part of the tubular member 23 is provided with an insertion tube 27 through which gas and the like can flow into and out of the closed space 28, and an opening on one end side of the insertion tube 27 is closed by a lid member 29. ing.

次に、本発明を適用した配管の補修方法において最も重要となる溶接条件について説明する。 Next, the most important welding conditions in the pipe repair method to which the present invention is applied will be described.

本願発明者は、内圧が負圧とされた配管に対して溶接をするにあたり、配管の破孔を確実に防止可能となるような溶接条件について鋭意研究を重ねた結果、配管の残存肉厚が３．２ｍｍ以上とされた部位であれば、溶接時においても破孔を生じず、更に、溶接対象の二部材間の溶け込み具合が良好な溶接が可能であることを見出した。また、本願発明者は、内圧が負圧とされた配管に対して溶接をする場合において、配管の残存肉厚の下限値が４．５ｍｍ以上であれば、溶接時に生じる熱歪みや残留応力による悪影響が配管の内周面近傍にまで及ぶのを低減させることができ、補修作業後における損傷部３近傍の配管１の強度、信頼性を十分に確保できることを見出した。 The inventor of the present application has conducted extensive research on welding conditions that can reliably prevent the pipe from being broken when welding the pipe with the negative internal pressure. It was found that if the region was set to 3.2 mm or more, no puncture occurred during welding, and welding with a good penetration between the two members to be welded was possible. In addition, when the present inventor performs welding on a pipe whose internal pressure is a negative pressure, if the lower limit value of the remaining thickness of the pipe is 4.5 mm or more, it is caused by thermal distortion or residual stress generated during welding. It has been found that the adverse effect can be reduced to the vicinity of the inner peripheral surface of the pipe, and the strength and reliability of the pipe 1 in the vicinity of the damaged portion 3 after the repair work can be sufficiently secured.

従って、本発明における溶接条件として、配管の残存肉厚は、その下限値として３．２ｍｍ以上であることを必要とする。また、配管の残存肉厚の下限値は、上述のように、４．５ｍｍ以上であれば一層好ましい。また、配管の残存肉厚の上限値は、特に限定するものではないが、配管１の損傷部３から管軸方向に離間するにつれて腐食の程度が軽くなる場合が多く、配管の残存肉厚を厚く設定するほど損傷部３の管軸方向両側に取り付けられるリング状部材２１間の間隔が広くなり、これに伴って筒状部材２３の管軸方向の長さが長くなる。このため、筒状部材２３の部材コストの高騰、筒状部材２３の取り付け作業性の低下を招くことになるため、配管の残存肉厚の上限値は、５ｍｍ以下とすることが好ましい。 Therefore, as a welding condition in the present invention, the remaining thickness of the pipe needs to be 3.2 mm or more as its lower limit. Further, as described above, the lower limit value of the remaining thickness of the pipe is more preferably 4.5 mm or more. The upper limit value of the remaining thickness of the pipe is not particularly limited, but the degree of corrosion often decreases as the distance from the damaged portion 3 of the pipe 1 in the pipe axis direction increases. As the thickness is increased, the interval between the ring-shaped members 21 attached to both sides of the damaged portion 3 in the tube axis direction is increased, and accordingly, the length of the tubular member 23 in the tube axis direction is increased. For this reason, since the member cost of the cylindrical member 23 will rise, and the attachment workability | operativity of the cylindrical member 23 will fall, it is preferable that the upper limit of the residual thickness of piping shall be 5 mm or less.

なお、ここでいう配管の残存肉厚とは、超音波探傷法、渦流探傷法等に基づく板厚測定装置によって測定される、腐食によって減肉されていない管の厚みのことをいう。ここでいう板厚測定装置とは、主として接触子と装置本体とを備えており、接触子から配管に超音波信号や渦電流を流し、腐食の有無や腐食部の形状等によって変化する測定信号をこの接触子によって受信し、得られた測定信号を装置本体で処理して配管の残存肉厚を表示する装置のことをいう。この配管の残存肉厚を測定する装置、方法は、公知の配管の残存肉厚を測定可能な装置、方法であれば特に限定するものではない。 Here, the residual thickness of the pipe means the thickness of the pipe that has not been reduced by corrosion, as measured by a plate thickness measuring device based on an ultrasonic flaw detection method, an eddy current flaw detection method, or the like. The plate thickness measuring device mentioned here mainly comprises a contactor and the device body, and an ultrasonic signal or eddy current flows from the contactor to the pipe, and the measurement signal changes depending on the presence or absence of corrosion, the shape of the corroded part, etc. Is a device that displays the remaining thickness of the pipe by processing the obtained measurement signal in the device body. The apparatus and method for measuring the remaining thickness of the pipe are not particularly limited as long as it is a known apparatus and method capable of measuring the remaining thickness of the pipe.

また、溶接に際して溶接棒に通電される電流値は、特に限定するものではないが、例えば、１００〜２００Ａとなる。また、溶接に際して用いられる溶接棒の直径は、特に限定するものではないが、例えば、２〜５ｍｍ（φ）となる。配管の残存肉厚、電流値、溶接棒の直径をこれらの範囲内にしつつ、配管１の全周に沿ってリング状部材２１を溶接により周設すれば、一層確実に破孔を防ぎつつ溶接が可能となる。 Moreover, the value of the current supplied to the welding rod during welding is not particularly limited, but is, for example, 100 to 200A. Moreover, the diameter of the welding rod used in welding is not particularly limited, but is, for example, 2 to 5 mm (φ). If the ring-shaped member 21 is provided by welding along the entire circumference of the pipe 1 while keeping the remaining wall thickness, current value, and diameter of the welding rod within these ranges, welding can be performed more reliably while preventing breakage. Is possible.

次に、本発明を適用した配管の補修方法の作業工程について説明する。なお、説明の簡略化のために、架台１０を省略した配管１に対して補修を行う場合を例にとって説明する。 Next, the work process of the pipe repair method to which the present invention is applied will be described. For the sake of simplification of explanation, a case where repair is performed on the pipe 1 from which the gantry 10 is omitted will be described as an example.

まず、上述の板厚測定装置によって、損傷部３近傍の配管の全周における配管肉厚を測定する。測定は、損傷部３が形成されている近傍の配管全周からまず行い、配管の全周の残存肉厚が３．２ｍｍ未満であった場合は、損傷部３から管軸方向に向けて離間する方向に測定箇所を変更し、配管の全周の残存肉厚が３．２ｍｍ以上の部位が測定されるまで行なう。そして、配管の全周の残存肉厚が３．２ｍｍ以上とされた部位を、分割リング状部材２２を取り付ける取付部４１とする。 First, the pipe thickness at the entire circumference of the pipe near the damaged portion 3 is measured by the above-described plate thickness measuring device. The measurement is first performed from the entire circumference of the pipe in the vicinity where the damaged portion 3 is formed. If the remaining thickness of the entire circumference of the pipe is less than 3.2 mm, the measurement is separated from the damaged portion 3 in the pipe axis direction. The measurement location is changed in the direction to be measured, and the measurement is performed until the location where the remaining thickness of the entire circumference of the pipe is 3.2 mm or more is measured. Then, a portion where the remaining thickness of the entire circumference of the pipe is 3.2 mm or more is defined as an attachment portion 41 to which the split ring member 22 is attached.

次に、図５に示すように、損傷部３から管軸方向の両側に位置する取付部４１に対して、その外周面の全周に沿ってリング状部材２１（分割リング状部材２２）の内周面を溶接により周設する。この場合において、取付部４１の外周面の全周に沿って溶接線Wが位置するように溶接することになる。この場合において、損傷部３に近接するにつれて配管の全周の残存肉厚が薄くなるため、溶接による破孔を防止し、安全性を向上させる観点から、図５（ａ）に示すような、リング状部材２１（分割リング状部材２２）の外側側面２２ｄ、内側側面２２ｅのうち、損傷部３から離間する側に位置する外側側面２２ｄから溶接を施すことが望ましい。また、二つの分割リング状部材２２の径方向の両端部２２ｃは、互いに突き合せたうえで、溶接により接合する。 Next, as shown in FIG. 5, the ring-shaped member 21 (divided ring-shaped member 22) is arranged along the entire circumference of the outer peripheral surface of the mounting portion 41 located on both sides in the tube axis direction from the damaged portion 3. The inner peripheral surface is provided by welding. In this case, welding is performed so that the weld line W is located along the entire circumference of the outer peripheral surface of the mounting portion 41. In this case, since the remaining thickness of the entire circumference of the pipe becomes thinner as it approaches the damaged portion 3, from the viewpoint of preventing breakage due to welding and improving safety, as shown in FIG. Of the outer side surface 22d and the inner side surface 22e of the ring-shaped member 21 (divided ring-shaped member 22), it is desirable to perform welding from the outer side surface 22d located on the side away from the damaged portion 3. Further, both end portions 22c in the radial direction of the two divided ring-shaped members 22 are joined to each other after being abutted with each other.

次に、図６に示すように、損傷部３を跨るように、損傷部３の管軸方向の両側に位置するリング状部材２１に対して、その外周面の全周に沿って筒状部材２３（上部分割筒状部材２４、下部分割筒状部材２５）を溶接により周設する。この場合において、リング状部材２１の外周面の全周に沿って溶接線４５が位置することになる。また、二つの分割筒状部材２４、２５の径方向の両端部２４ｃ、２５ｃは、互いに突き合わせたうえで、溶接により接合する。 Next, as shown in FIG. 6, with respect to the ring-shaped member 21 positioned on both sides of the damaged portion 3 in the tube axis direction so as to straddle the damaged portion 3, the cylindrical member is disposed along the entire outer peripheral surface thereof. 23 (upper divided cylindrical member 24, lower divided cylindrical member 25) are provided by welding. In this case, the weld line 45 is located along the entire circumference of the outer peripheral surface of the ring-shaped member 21. Further, both end portions 24c and 25c in the radial direction of the two divided cylindrical members 24 and 25 are joined to each other after being brought into contact with each other.

この場合において、リング状部材２１の側壁、筒状部材２３の内周面並びに損傷３近傍の配管１外周面によって包囲された閉空間２８内に不活性ガスを挿通管２７から流入させながら、溶接施工をするのが好ましい。これによって、溶接時に高温となる中空ボックス体３１内面側の溶接部の酸化の防止を図りつつ溶接をおこなうことが可能となる。 In this case, welding is performed while flowing an inert gas from the insertion tube 27 into the closed space 28 surrounded by the side wall of the ring-shaped member 21, the inner peripheral surface of the cylindrical member 23, and the outer peripheral surface of the pipe 1 near the damage 3. Construction is preferable. This makes it possible to perform welding while preventing oxidation of the welded portion on the inner surface side of the hollow box body 31 that becomes a high temperature during welding.

次に、図７に示すように、閉空間２８内に不活性ガスを挿通管２７から流入させて、挿通管２７に蓋部材２９を嵌め込んで閉塞させ、閉空間２８内に不活性ガスを封入させる。これによって、損傷部３の腐食の発生、進行を防止することが可能となる。なお、不活性ガスは、Ｎ₂，Ｈｅ，Ａｒ，Ｋｒ，Ｘｅ等の何れか一種または二種以上を混合してなるガスによって具体化される。 Next, as shown in FIG. 7, an inert gas is allowed to flow into the closed space 28 from the insertion tube 27, and a lid member 29 is fitted into the insertion tube 27 to close it, so that the inert gas is introduced into the closed space 28. Enclose. As a result, the occurrence and progression of corrosion of the damaged portion 3 can be prevented. The inert gas is embodied by a gas formed by mixing any one or two or more of N ₂ , He, Ar, Kr, Xe and the like.

このように、本発明を適用した配管の補修方法によって、従来において溶接による補修が困難であった、内圧が負圧とされた配管に対してでも、破孔を生じさせることなく溶接による補修を施すことが可能となり、これを利用して、損傷部３に対して接触等することなく補修を完了させることができる。特に、閉空間２８を形成しているリング状部材２１、筒状部材２３並びに配管１は、溶接することによって互いに接合されているため、閉空間をシーリング材やパッキン等によって形成した場合と比較して閉空間２８内の密閉性が良好に保たれており、これに伴い、その内部に封入された不活性ガスの漏洩を確実に防止可能となる。このような不活性ガスを封入した閉空間に配置される損傷部は、腐食が非常に進行しにくく、パテのような硬化性充填材を塗布して補修を施した場合と比較して、耐腐食性能が大きく向上していることになる。 As described above, by the pipe repair method to which the present invention is applied, it has been difficult to repair by welding, and it has been difficult to repair by welding without generating a hole even in a pipe having a negative internal pressure. This can be applied, and this can be used to complete the repair without contacting the damaged portion 3. In particular, since the ring-shaped member 21, the cylindrical member 23, and the pipe 1 that form the closed space 28 are joined to each other by welding, compared with the case where the closed space is formed by a sealing material, packing, or the like. Thus, the hermeticity in the closed space 28 is maintained well, and accordingly, it is possible to reliably prevent the leakage of the inert gas sealed therein. Damaged parts placed in a closed space filled with such an inert gas are less prone to corrosion, and are more resistant to damage when applied by applying a curable filler such as putty. Corrosion performance is greatly improved.

また、本発明を適用した配管の補修方法によれば、配管１の切断等することなく補修が完了するため、配管１内のガス流通を停止することなく補修を確実に行なうことができる。 Further, according to the pipe repair method to which the present invention is applied, the repair is completed without cutting the pipe 1 or the like, so that the repair can be reliably performed without stopping the gas flow in the pipe 1.

なお、補修後においては、適宜、中空ボックス体３１の外面に塗装等を施したり、防食被覆を設けるようにしてもよい。また、損傷部３に対してガス移送経路の下流側では、ガス検知器等の管内の酸素濃度を監視する手段によって、管内の酸素濃度が１％以下の条件下で上記補修工程が行われるようにして、作業の安全性を高めるようにしてもよい。 In addition, after repairing, you may make it apply | coat etc. to the outer surface of the hollow box body 31, and may provide anticorrosion coating | covering suitably. Further, on the downstream side of the gas transfer path with respect to the damaged portion 3, the above repair process is performed under the condition that the oxygen concentration in the tube is 1% or less by means of monitoring the oxygen concentration in the tube such as a gas detector. Thus, work safety may be improved.

また、筒状部材２３をリング状部材２１に対して溶接接合する前において、架台１０のバンド部１５や受け部１１近傍における配管１外周面の損傷がひどく、その一部において孔が開口されている場合には、パテ等の硬化性充填材を損傷部３に塗布して、開口を塞ぐようにしてもよい。 Further, before the cylindrical member 23 is welded to the ring-shaped member 21, the outer peripheral surface of the pipe 1 near the band portion 15 and the receiving portion 11 of the gantry 10 is seriously damaged, and a hole is opened in a part thereof. If it is, a curable filler such as putty may be applied to the damaged part 3 to close the opening.

また、図３に示すように、筒状部材２３の取り付けに際して、下部分割筒状部材２５の切欠２６内に嵌まるように配置される架台１０の脚部１３は、閉空間２８内の密閉性を確保するために、その切欠２６近傍の下部分割筒状部材２５に溶接により接合されることになる。 Further, as shown in FIG. 3, when attaching the cylindrical member 23, the leg portion 13 of the gantry 10 disposed so as to fit in the notch 26 of the lower divided cylindrical member 25 is sealed in the closed space 28. In order to ensure this, the lower divided cylindrical member 25 in the vicinity of the notch 26 is joined by welding.

因みに、本発明の適用の対象となる配管１は、コークス炉に設置されている配管１のみに限定するものではなく、例えば、高炉、転炉等のプラント設備をはじめとして、様々な設備内外に設置されるものであり、その設置される箇所は、屋内、屋外を問わない。 Incidentally, the pipe 1 to which the present invention is applied is not limited to the pipe 1 installed in the coke oven, and for example, inside and outside various facilities including plant facilities such as a blast furnace and a converter. It is installed, and the installation location may be indoors or outdoors.

また、配管１の補修時に配管１に対して取り付けられる中空ボックス体３１は、図８（ａ）〜（ｅ）に示すように、直線状の配管１Ａの他に、曲線状の配管１Ｂ、テーパ形状の配管１Ｃ、フランジ部近傍の配管１Ｄ、分枝管が設けられた配管１Ｅ等のように種々の形状の配管に対して適用できる。特に、テーパ形状の配管１Ｃやフランジ部近傍の配管１Ｄに対して筒状部材２３を取り付ける場合、配管の外周面の形状と略相似形状の分割筒状部材を取り付けるようにして、補修後において中空ボックス体３１が占有する空間体積を低減させ、省スペース性に寄与するようにしてもよい。 Moreover, the hollow box body 31 attached with respect to the piping 1 at the time of repair of the piping 1 is the curved piping 1B, taper other than the linear piping 1A, as shown to Fig.8 (a)-(e). The present invention can be applied to pipes of various shapes such as a pipe 1C having a shape, a pipe 1D near the flange, a pipe 1E provided with a branch pipe, and the like. In particular, when the cylindrical member 23 is attached to the pipe 1C having a tapered shape or the pipe 1D in the vicinity of the flange portion, it is hollow after the repair by attaching a divided cylindrical member having a shape substantially similar to the shape of the outer peripheral surface of the pipe. The space volume occupied by the box body 31 may be reduced to contribute to space saving.

以下、本発明の効果を実施例により詳細に説明する。なお、本発明は下記実施例に限定されるものではない。本実施例においては、引張強度が４００ＭＰａ級の鋼板によって、図９（ａ）、図９（ｂ）に示すような、一面側が開口された立方体状のボックス体６１と、ボックス体の開口縁に溶接等により固着された試験鋼板６２とにより、内部に閉空間６３を有するような試験体６０を形成した。なお、図９（ａ）は、試験体６０の正面図、図９（ｂ）は、図９（ａ）のＤ−Ｄ線断面図を示している。 Hereinafter, the effects of the present invention will be described in detail with reference to examples. In addition, this invention is not limited to the following Example. In this embodiment, a steel box having a tensile strength of 400 MPa is used to form a cubic box body 61 having one side opened as shown in FIGS. 9A and 9B, and an opening edge of the box body. A test body 60 having a closed space 63 inside was formed by the test steel plate 62 fixed by welding or the like. 9A is a front view of the test body 60, and FIG. 9B is a cross-sectional view taken along the line DD of FIG. 9A.

このボックス体６１の前面６１aにはガラス窓６５を設けるとともに、ボックス体６１の両側面６１ｃに対しては、ボックス体６１と試験鋼板６２とによって囲まれた閉空間６３にガスの流出入を可能とする挿通管６７を設けた。一方の挿通管６７を介して窒素ガスを流入させるとともに、他方の挿通管６７からボックス体６１内の気体を吸入し、ボックス体６１の内圧が−７ｋＰａとなるよう調整した。 A glass window 65 is provided on the front surface 61 a of the box body 61, and gas can flow into and out of the both sides 61 c of the box body 61 into a closed space 63 surrounded by the box body 61 and the test steel plate 62. An insertion tube 67 is provided. Nitrogen gas was introduced through one insertion tube 67 and the gas in the box body 61 was sucked from the other insertion tube 67 to adjust the internal pressure of the box body 61 to −7 kPa.

試験鋼板６２は、１．６ｍｍ〜６．０ｍｍの範囲の種々の板厚のものを用いた。試験鋼板６２の表面６２ａに対しては、図９（ｂ）に示すように、試験鋼板６２と同一の材質からなる被溶接鋼板６９を重ね合わせ、試験鋼板６２と被溶接鋼板６９とを隅肉溶接により溶接接合した。 As the test steel plate 62, steel plates having various plate thicknesses ranging from 1.6 mm to 6.0 mm were used. On the surface 62a of the test steel plate 62, as shown in FIG. 9B, a welded steel plate 69 made of the same material as the test steel plate 62 is overlapped, and the test steel plate 62 and the welded steel plate 69 are filled with fillet. Welded by welding.

試験鋼板６２の板厚、溶接棒の直径、溶接時に通電した電流値各種条件については、下記表１に示すような条件下にて溶接を行なった。そして、その結果を、表１に示すように、破孔の有無、裏面発光の有無によって評価した。なお、ここでいう試験鋼板６２の板厚は、上記のリング状部材２１が溶接により周設されることになる配管の残存肉厚に対応している。また、「破孔の有無」とは、溶接によって試験鋼板６２に形成される破孔の有無のことを示し、破孔が形成されることによってガラス窓６５に溶接スラッジが付着した場合を×とし、貫通孔が形成されず、ガラス窓に溶接スラッジが付着しなかった場合を○とした。また、「裏面発光の有無」とは、溶接によって試験鋼板６２の裏面６２ｂに発生する発光の有無のことを示し、溶接時において試験鋼板６２の裏面６２ｂに発光が生じているのが、ガラス窓６５から目視により確認された場合を×、確認されない場合を○とした。 Regarding the thickness of the test steel plate 62, the diameter of the welding rod, and various conditions of the current value energized during welding, welding was performed under the conditions shown in Table 1 below. Then, as shown in Table 1, the results were evaluated by the presence or absence of broken holes and the presence or absence of backside light emission. Note that the thickness of the test steel plate 62 here corresponds to the remaining thickness of the pipe in which the ring-shaped member 21 is to be provided by welding. Further, “presence / absence of broken hole” indicates the presence / absence of a broken hole formed in the test steel plate 62 by welding. The case where no through-hole was formed and no welding sludge adhered to the glass window was marked as ◯. Further, “presence / absence of light emission from the back surface” indicates whether light emission is generated on the back surface 62b of the test steel plate 62 by welding, and light emission is generated on the back surface 62b of the test steel plate 62 during welding. The case where it was visually confirmed from 65 was marked as x, and the case where it was not confirmed was marked as ◯.

上記表１に示すように、サンプルＮｏ．Ａ１、Ｎｏ．Ａ２の条件下においては、板厚が本発明の要件を満足していないため、溶接時に試験鋼板６２が破孔してしまった。これに対して、サンプルＮｏ．Ａ３〜Ｎｏ．Ａ１０の条件下においては、板厚が本発明の要件を満足しているため、溶接時に試験鋼板６２が破孔することがなかった。これによって、内圧が負圧とされた配管に対してでも、本発明を適用することによって、破孔を生じさせることなく溶接を行なうことが可能となることが確認された。 As shown in Table 1 above, Sample No. A1, No. Under the conditions of A2, since the plate thickness does not satisfy the requirements of the present invention, the test steel plate 62 broke during welding. In contrast, sample no. A3-No. Under the conditions of A10, since the plate thickness satisfied the requirements of the present invention, the test steel plate 62 did not break during welding. As a result, it was confirmed that welding can be performed without causing a broken hole by applying the present invention even to a pipe having a negative internal pressure.

また、上記の表１に示すように、サンプルＮｏ．Ａ１〜Ｎｏ．Ａ５の条件下においては、裏面発光が確認され、サンプルＮｏ．Ａ６〜Ｎｏ．Ａ１０の条件下においては、裏面発光が確認されなかった。裏面発光が確認される場合は、溶接時において、試験鋼板６２の裏面６２ｂにまで発光するほど高温の熱が溶接により伝達されており、溶接時に生じる熱歪みや残留応力による悪影響が試験鋼板６２の裏面６２ｂにまで及んでいると考えられる。このため、溶接作業後における溶接部近傍の試験鋼板の強度、信頼性を確保する観点からは、試験鋼板６２の板厚を４．５ｍｍ以上とすることが望ましいことが確認された。 As shown in Table 1 above, sample No. A1-No. Under the conditions of A5, backside light emission was confirmed, and sample no. A6-No. Under the condition of A10, backside light emission was not confirmed. In the case where backside light emission is confirmed, at the time of welding, heat that is so high that light is emitted to the back surface 62b of the test steel plate 62 is transmitted by welding. It is thought that it extends to the back surface 62b. For this reason, from the viewpoint of ensuring the strength and reliability of the test steel plate in the vicinity of the weld after the welding operation, it was confirmed that the thickness of the test steel plate 62 is desirably 4.5 mm or more.

次に、内圧が負圧とされたガス配管に対して、実際に本発明を適用して補修を施した実施例について説明する。 Next, a description will be given of an embodiment in which the present invention is actually applied to a gas pipe whose internal pressure is negative.

補修の対象としては、二種類のガス配管１を選定した。一方のガス配管１の寸法は、直径２０００ｍｍ、全肉厚１２ｍｍであり、他方のガス配管１の寸法は直径１５００ｍｍ、全肉厚１０ｍｍである。何れのガス配管１も、その内圧が−６５０ｍｍＡｑとされており、更に何れも引張強度が４００ＭＰａ級の鋼板から構成されている。 Two types of gas pipes 1 were selected for repair. One gas pipe 1 has a diameter of 2000 mm and a total wall thickness of 12 mm, and the other gas pipe 1 has a diameter of 1500 mm and a total wall thickness of 10 mm. All the gas pipes 1 have an internal pressure of −650 mmAq, and all are made of a steel plate having a tensile strength of 400 MPa.

リング状部材２１は、図４（ａ）に示すような、半割リング状の形状からなる二つの分割リング状部材２２を用いた。分割リング状部材の高さＨ１は６５ｍｍであり、厚みは８ｍｍであり、径方向の幅Ｗ１は４００ｍｍである。筒状部材２３は、分割リング状部材２２が配管に取り付けられた後に、各分割リング状部材２２の外周面２２ｂに沿って配置される一枚の鋼板から構成され、管軸方向の長さが４５０ｍｍであり、厚みは８ｍｍである。また、分割リング状部材２２、筒状部材２３の何れも引張強度が４００ＭＰａ級の鋼板から構成されている。 As the ring-shaped member 21, two split ring-shaped members 22 having a half-ring shape as shown in FIG. The divided ring-shaped member has a height H1 of 65 mm, a thickness of 8 mm, and a radial width W1 of 400 mm. The tubular member 23 is composed of a single steel plate disposed along the outer peripheral surface 22b of each divided ring-shaped member 22 after the divided ring-shaped member 22 is attached to the pipe, and has a length in the tube axis direction. It is 450 mm and the thickness is 8 mm. Each of the split ring-shaped member 22 and the cylindrical member 23 is made of a steel plate having a tensile strength of 400 MPa.

補修時においては、まず、損傷部３近傍の配管の全周における残存肉厚を、超音波探傷法に基づく板厚測定装置によって測定した。これによって、配管の全周の残存肉厚が５ｍｍの位置を検出し、この位置に対して、配管の全周に沿って分割リング状部材２２を溶接により周設した。分割リング状部材２２を取り付けるにあたって、溶接棒の直径は３．２ｍｍとし、電流値は１００Ａとした。なお、損傷部３の両側に位置する分割リング状部材２２の間の間隔は、４５０ｍｍとなった。 At the time of repair, first, the remaining thickness of the entire circumference of the pipe near the damaged portion 3 was measured by a plate thickness measuring device based on an ultrasonic flaw detection method. As a result, a position where the remaining thickness of the entire circumference of the pipe was 5 mm was detected, and the split ring-shaped member 22 was provided around the position by welding along the whole circumference of the pipe. In attaching the split ring-shaped member 22, the diameter of the welding rod was 3.2 mm, and the current value was 100A. In addition, the space | interval between the division | segmentation ring-shaped members 22 located in the both sides of the damage part 3 became 450 mm.

次に、損傷部３の管軸方向の両側に位置するリング状部材２１に対して、その外周面の全周に沿って筒状部材２３を溶接により周設した。筒状部材２３を分割リング状部材２２に取り付けるに当たって、溶接棒の直径は４．０ｍｍとし、電流値は１７０Ａとした。 Next, a cylindrical member 23 was provided by welding along the entire circumference of the outer peripheral surface of the ring-shaped member 21 located on both sides of the damaged portion 3 in the tube axis direction. In attaching the cylindrical member 23 to the split ring-shaped member 22, the diameter of the welding rod was 4.0 mm, and the current value was 170A.

次に、リング状部材２１の側壁、筒状部材２３の内周面並びに配管１の外周面によって包囲された閉空間２８内にＮ_２ガスを封入した。 Next, N ₂ gas was sealed in the closed space 28 surrounded by the side wall of the ring-shaped member 21, the inner peripheral surface of the cylindrical member 23, and the outer peripheral surface of the pipe 1.

このような条件下で損傷部３の補修を行ったところ、配管１の破孔が生じることなく、作業全工程が完了した。これにより、内圧が負圧とされた配管に対して、本発明の補修方法を適用した場合に、破孔を生じさせることなく補修作業を完了させることが可能であることが確認された。 When the damaged portion 3 was repaired under such conditions, the entire work process was completed without causing the pipe 1 to break. Thus, it was confirmed that when the repair method of the present invention is applied to a pipe whose internal pressure is a negative pressure, it is possible to complete the repair work without causing a hole.

本発明の適用の対象となる配管が設置されているコークス炉の概略配管図である。It is a schematic piping diagram of the coke oven in which piping used as the object of application of the present invention is installed. 本発明の適用の対象となる配管の一例を示す図であり、（ａ）はその側面図を、（ｂ）は（ａ）の正面図である。It is a figure which shows an example of the piping used as the object of application of this invention, (a) is the side view, (b) is a front view of (a). 配管に対して補修を施した後の状態を示す図であり、（ａ）はその側面図を（ｂ）はそのＡ−Ａ線断面図である。It is a figure which shows the state after performing repair with respect to piping, (a) is the side view, (b) is the sectional view on the AA line. 配管の補修時に用いられる分割リング状部材と分割筒状部材との構成を示す斜視図である。It is a perspective view which shows the structure of the division | segmentation ring-shaped member used at the time of repair of piping, and a division | segmentation cylindrical member. 補修時において分割リング状部材を配管に取り付ける状態を示す図であり、（ａ）はその側面図を、（ｂ）は（ａ）のＢ−Ｂ線断面図である。It is a figure which shows the state which attaches a division | segmentation ring-shaped member to piping at the time of repair, (a) is the side view, (b) is the BB sectional drawing of (a). 補修時において分割筒状部材をリング状部材に取り付ける状態を示す図であり、（ａ）はその一部切欠側面図を、（ｂ）は（ａ）のＣ−Ｃ線断面図である。It is a figure which shows the state which attaches a division | segmentation cylindrical member to a ring-shaped member at the time of repair, (a) is the partially notched side view, (b) is CC sectional view taken on the line of (a). 補修時においてリング状部材等がなす閉空間内に不活性ガスを封入する状態を示す一部切欠側面図である。It is a partially cutaway side view showing a state in which an inert gas is sealed in a closed space formed by a ring-shaped member or the like at the time of repair. 本発明の適用の対象となる配管の形状の例を示す側面図である。It is a side view which shows the example of the shape of piping used as the object of application of this invention. 実施例における試験条件について説明するための図である。It is a figure for demonstrating the test conditions in an Example.

Explanation of symbols

１配管
３損傷部
５コークス炉
７配管固定具
９床壁
１０架台
１１受け部
１３脚部
１５バンド部
２１リング状部材
２２分割リング状部材
２３筒状部材
２４上部分割筒状部材
２５下部分割筒状部材
２６切欠
２７挿通管
２８閉空間
２９蓋部材
３１中空ボックス体
４１取付部
５１炉本体
５３ドライメーン
５５プライマリクーラー
５７ガスブロワー
６１ボックス体（実施例）
６２試験鋼板
６３閉空間
６５ガラス窓
６７挿通管
６９被溶接鋼板
Ｗ溶接線 DESCRIPTION OF SYMBOLS 1 Piping 3 Damaged part 5 Coke oven 7 Piping fixture 9 Floor wall 10 Mounting base 11 Receiving part 13 Leg part 15 Band part 21 Ring-shaped member 22 Split ring-shaped member 23 Cylindrical member 24 Upper divided cylindrical member 25 Lower divided cylindrical shape Member 26 Notch 27 Insertion tube 28 Closed space 29 Lid member 31 Hollow box body 41 Mounting portion 51 Furnace body 53 Dry main 55 Primary cooler 57 Gas blower 61 Box body (Example)
62 Test steel plate 63 Closed space 65 Glass window 67 Insertion pipe 69 Welded steel plate W Welding line

Claims

In the repairing method of the gas pipe that repairs the damaged part formed on the outer peripheral surface of the gas pipe whose internal pressure is negative,
A ring-shaped member is provided by welding along the entire circumference of the portion located on both sides in the tube axis direction from the damaged portion and having a remaining thickness of 3.2 mm or more in the entire circumference of the gas pipe. ,
A cylindrical member is provided so as to straddle the damaged portion along the entire circumference of the outer periphery of the ring-shaped member provided on both sides in the tube axis direction of the damaged portion,
A repair method for a gas pipe, wherein an inert gas is sealed in a closed space surrounded by a side surface of the ring-shaped member, an inner peripheral surface of the cylindrical member, and an outer peripheral surface of the pipe.

The method for repairing a gas pipe according to claim 1, wherein the ring-shaped member is provided by welding to a portion where the remaining thickness of the entire circumference of the gas pipe is 4.5 mm or more.

In the repair structure of the gas pipe that repairs the damaged part formed on the outer peripheral surface of the gas pipe whose internal pressure is negative,
A ring-shaped member is provided by welding along the entire circumference of the portion located on both sides in the tube axis direction from the damaged portion and having a remaining thickness of 3.2 mm or more in the entire circumference of the gas pipe. ,
A cylindrical member is provided so as to straddle the damaged portion along the entire circumference of the outer periphery of the ring-shaped member provided on both sides in the tube axis direction of the damaged portion,
A repair structure for a gas pipe, wherein an inert gas is enclosed in a closed space surrounded by a side surface of the ring-shaped member, an inner peripheral surface of the cylindrical member, and an outer peripheral surface of the pipe.

The repair structure for a gas pipe according to claim 3, wherein the ring-shaped member is provided around a portion where the remaining thickness of the entire circumference of the gas pipe is 4.5 mm or more.