JP4151054B2 - Continuous repair method for large diameter pipes - Google Patents

Description

  The present invention relates to a method for continuously repairing a large-diameter pipe that guides the flow of combustible gas or oil and transfers them to a remote location.

Pipe lines can be partially consumed, leading to thinning and holes. In such a case, repair is performed such that the metal plate is welded to a thinned part or a holed part to reinforce or block the hole (for example, see Patent Document 1).
JP 2003-80392 A

  In pipes that guide the flow of substances such as flammable gas and oil, if the wall of the pipe where the contact plate is welded is too thin or has a hole in the tube wall, the contact plate There is a case where the welding heat ignites the substance in the pipe line or the substance leaked from the pipe line and causes an explosion. In order to cope with this, when welding the contact plate, after the combustible gas or oil in the pipeline is discharged, the use of the pipeline is stopped.

  In the initial wear of the pipeline, the area to be applied with the patch plate is generally narrow, so the period of stoppage of the pipeline required for repair can be shortened, but when the wear of the pipeline progresses in a wide range, It is necessary to replace the pipeline itself with a new one, and in this case, especially when the pipeline is a large-diameter pipe, the period of suspension of use of the pipeline required for the repair becomes longer. . For example, if the diameter of the pipe repairing part is 2 m to 3 m and the length is about 10 m, the period of suspension of use of the pipe required for repairing may be about 15 to 20 days.

  On the other hand, if the pipeline to be repaired is, for example, one that supplies flammable gas used as power generation fuel, it is not permitted to stop using the pipeline for a long time. Shortening is required.

  The present invention has been made in view of such a requirement, that is, a pipe required for repairing a pipe line formed by connecting a large number of unit pipes having a specific width and a large diameter. The purpose is to drastically shorten the road suspension period.

  In order to achieve the above object, a continuous pipe repairing method according to the present invention includes a pipe line formed by connecting a large number of unit pipes having a specific width and a large diameter as described in claim 1. When continuously repairing across multiple unit tubes, a pair of seal rings are attached to the outer periphery of the unit tube at a fixed distance to be repaired, and the units between these pair of seal rings A plurality of repair sections are formed in the outer space around the tube by alternately connecting stay members with appropriate lengths and support members with appropriate outer diameters, and a pair of seal rings at both ends at the beginning are attached to the outer periphery of the unit tube. An arc-shaped overlapping plate, which is fixed by welding and then cut in half for each repair section, is hermetically covered to the outer periphery of the unit pipe under a fixed gap via the stay member and the support member.

  More specifically, after the flow of the fluid in the pipe is stopped only at the time of initial welding, the pair of seal rings is performed as described in claim 2. Is performed without stopping the fluid flow in the pipeline during repair work in other repair sections.

According to the present invention, the following effects can be obtained.
That is, according to the first aspect, even when the diameter and length of the fixed length portion, which is a repaired portion of the large-diameter pipe through which the combustible gas or the like flows, reach several meters or more. In the repair, it is only necessary to stop the use of the pipe line only when the seal ring is installed, and the rest can be efficiently repaired without blocking the flow of flammable gas in the pipe line. Therefore, the larger the pipe diameter to be repaired and the longer the length range, the shorter and safer and cheaper repair work can be performed compared to the conventional method. Become.

  As an example, when the pipe diameter of the pipe to be repaired is about 2 m and its length is about 10 m, the conventional work requires about 15 to 20 days as the pipe stoppage period. However, according to the present invention, only one day is required, and the economic cost effect is outstanding.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a schematic explanatory view showing a continuous repair method for a large-diameter pipe according to the present invention, FIG. 2 is a perspective view showing a seal ring used in the repair method, and FIG. 3 is a schematic description showing a progress state of the repair method. FIG.

In FIG. 1, reference numeral 1 denotes a pipe made of a large-diameter pipe having a diameter of about 2 m or more, and is originally formed by continuously welding a plurality of pipes having a constant width. This pipe line 1 guides an arbitrary fluid substance, but here, the combustible gas discharged from the steelmaking blast furnace is supplied to the power plant as a power generation fuel. In the illustrated example, reference numeral 2 denotes a bent portion formed in the middle of the pipeline 1, which functions as a water seal valve.
Here, 1a is a unit pipe that forms a straight pipe, and 1b is a curved pipe unit that forms the bent portion.

  When the combustible gas discharged from the steelmaking blast furnace flows in the pipe, the pipe wall surface of the bent portion 2 is consumed relatively quickly with time. The entire pipe wall surface is thinned and the holes are locally or continuously opened.

  When the thinned pipe line in such a state is generated in a wide range across the plurality of unit pipes 1b, the repair work is carried out according to the following procedure in the present invention.

In the drawing of the embodiment, it is understood that a large number of pipes having a thickness of 3 mm or less are generated in the bent portion 2 in the measurement of the wall thickness of the pipe line, and the entire range H of the bent portion 2 is repaired.
First, a pair of seal rings 3a and 3b are respectively attached to the outer peripheral surfaces of the pipes at specific positions p1 and p2 that form the start and end of the entire surface repair range portion H through fastening means.
As shown in FIG. 2, each of the seal rings 3a and 3b is composed of two substantially semi-annular members 4 and 4 and is formed into an annular shape as a whole. Each of the substantially semi-annular members 4 has a width of, for example, 100 mm and is thick. A band plate having a length of about 6 mm is bent with a dimension suitable for the outer periphery of the unit tube 1b with a certain gap.

  When the seal rings 3a and 3b are attached, for example, L-shaped metal fittings 5 and 5 are fixed to respective end portions of the two substantially semi-annular members 4 and 4, and the two substantially semi-annular members 4 are attached. 4 is hung to a required position by a crane truck or the like and arranged on the outer peripheral surface of the pipe line so as to be fitted outside, and then the screw rod member 6 and the nut are engaged with the two L-shaped metal fittings 5 and 5 facing each other. It is fastened and fixed to the outer peripheral surface of the pipe in an outer fitting shape. At this time, it is preferable that the butted portions of the two substantially semi-annular members 4 and 4 are positioned at the horizontal diameter position of the pipe line 1 in order to facilitate the subsequent welding operation.

  Next, the pipe line 2 is brought into a non-use state, that is, in order to eliminate the combustible gas in the pipe line 2, for example, nitrogen gas is supplied into the pipe line 2. Replaced with gas. In this state, the entire circumference of the seal rings 3a and 3b at the specific positions p1 and p2 is welded to the pipe outer peripheral surface. Check by flaw detection test etc.).

In the present invention, when the welding and fixing of the seal rings 3a and 3b is completed, the inflow of the combustible gas in the pipe line 2 is restored, and the entire pipe line is returned to the original use state. Enters the following operation under the return condition of the pipe.
The pair of seal rings 3a and 3b are divided into a plurality of repair sections (20 in the illustrated example), and each section is divided into a support member 8 using a stay member 7 having an appropriate length, and the outer peripheral surface of the unit tube 1b. It will be installed on. Here, the stay member 7 and the support member 8 are attached to each other from one side of the seal rings 3a and 3b to the outer peripheral surface of the unit tube 1b while being welded to each other under a certain gap.

  Each of the supporting members 8 in the above is configured so that the members of a substantially semi-annular member are paired like the seal ring 3a (3b), and the distance s between adjacent portions is, for example, about 0.5 m to 2.0 m. Decide to be. At this time, in order to prevent the mounting position from being displaced, the wooden wedge 9 is appropriately sandwiched between the lower unit tube.

  Thus, when the arrangement of the support members 8 in the respective repair sections is completed, the support members 8 are welded to each other via the stay members 7 having appropriate lengths and are stably fixed. In this case, the wedge 9 is removed.

  As a result, the space on the outer peripheral surface of the unit pipe 1b between the start and end seal rings 3a, 3b of the repair section is a plurality of repair sections m1, which are alternately connected by the stay members 7 and the support members 8. It is divided into m2, m3,.

  Next, as shown in FIG. 3, arc-shaped overlapping plates 10 cut in half with respect to the respective repair sections m1, m2, m3,... Are brought into contact with both sides of the unit tube 1b, respectively. This is fixed by welding.

  The overlapping plate 10 disposed in each repair section s in the welding operation described above is welded close to the state where the opposing portions of the adjacent overlapping plates are in contact with each other, so that the sealing performance and appearance after the welding is finished are good. It is preferable for this.

  Thus, when the covering operation of the overlapping plate 10 is completed, the necessary sealing performance is inspected. Nitrogen gas is sealed in the gap between the outer periphery of the unit tube 1b and the covering overlapping plate 10. This is done and the repair work is completed by ensuring confidentiality.

  According to the above-described repair, it is only necessary to stop the fluid flow in the pipe line 1 during the time when the seal rings 3a and 3b are initially welded onto the existing pipe. It is greatly shortened, and overall, large-scale repair can be efficiently performed in a short time. In addition, although the said Example demonstrated the repair of the curved pipe line, it can implement similarly about the repair of a straight pipe line, and it shall be in the scope of implementation of this invention.

It is a schematic explanatory drawing which shows the structure of the repair section which concerns on this invention. It is a perspective view which shows the seal ring used with the said repair method. It is a schematic explanatory drawing which shows the repair work in the said repair section.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pipe line 1a Unit pipe 3a Seal ring 3b Seal ring 8 Supporting member 9 Stay member 10 Stack plate m1, m2, m3, ... Repair section

Claims (2)

  When continuously repairing a pipe line formed by connecting a large number of unit pipes with a specific width dimension across multiple unit pipes, the outer circumference of the unit pipes separated by a fixed distance A pair of seal rings are attached to the locations, and a plurality of unit tube outer peripheral spaces between the pair of seal rings are connected to each other while alternately connecting stay members having appropriate lengths and supporting members having appropriate outer diameters. A repair section is formed, and a pair of seal rings at both ends are welded and fixed to the outer periphery of the unit pipe, and thereafter, the arc-shaped overlapping plate that has been cut in half for each repair section is sequentially added to the stay member and the support member. A method for continuously repairing a large-diameter pipe, characterized in that the outer circumference of the unit pipe is hermetically covered under a certain gap through a gap.   2. The fluid flow in the pipeline is stopped only when the pair of seal rings are welded as described above, and the fluid flow in the pipeline is not stopped during the repair work of the other repair section. Continuous repair method for large-diameter pipes described.

Images