JP3615826B2 - Pipe repair welding method and apparatus - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a repair welding method and apparatus applied to a furnace wall tube of a power generation boiler.
[0002]
[Prior art]
If the furnace wall tube of a boiler in a conventional thermal power plant is damaged during operation, the scaffold material is carried into the furnace from the manhole after the furnace temperature is lowered, the scaffold is assembled, and then the furnace wall tube is repaired and welded. It was.
[0003]
In this case, for the circumferential welding of the damaged furnace wall tube, an operator is arranged on the inner surface and the outer surface of the furnace, and the welding is performed in half a circle.
[0004]
[Problems to be solved by the invention]
By the way, as mentioned above, when the furnace wall tube of the boiler of a conventional thermal power plant is damaged during operation, after lowering the furnace temperature, the scaffold material is carried into the furnace from the manhole, and the scaffold is assembled. The wall tube was repair welded.
[0005]
For this reason, there are problems in terms of time required for cooling the furnace temperature, attachment of scaffolding, dismantling period and man-hours.
[0006]
An object of the present invention is to solve these problems and to provide a new pipe repair welding method and apparatus for repair welding a damaged boiler furnace wall pipe during boiler operation.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the pipe repair welding method of the present invention, when repairing and welding a damaged boiler furnace wall pipe during boiler operation, after cutting and removing the damaged portion of the damaged pipe, inserting a new pipe, As a method of welding the existing pipe and the new pipe from the outer surface side of the furnace wall, a part of the small automatic TIG welding torch head is placed on the outer surface side of the furnace wall around the circumferential groove, sandwiching the circumferential joint portion of the existing pipe and the new pipe An opening is formed to allow the tube to be inserted into the inner surface of the tube, and automatic TIG welding is performed from the inner surface of the tube with the inserted welding torch first on the circumferential groove portion excluding the opening, and then the insertion tube is fitted to the opening. Is temporarily attached to the opening, and manual TIG welding is performed on the outer periphery of the insertion portion of the insertion tube.
[0008]
Further, as a welding apparatus for performing the above-mentioned pipe repair welding method, there are a small TIG welding torch inserted into the inner surface of the pipe, an ultra-small arc voltage control slide for moving the welding torch in the diameter direction in the pipe, a guide nozzle for the welding wire, tube axis of the welding situation monitoring fiber scope supported by pivotable rotary support arm about a, while allowing insertion of the support arm in the tube, the welding torch connected to the rotary support arm outside the tube surface swing motor, welding wire feeder and the coil of the welding wire was placed, further connecting the turning motor arranged on the rotating shaft and outside the tube of the welding torch be placed in a tube as pivoting means of the welding torch with belts Is preferred.
[0009]
[Action]
When the boiler furnace wall tube is damaged during boiler operation, repair welding is possible only from the outer surface side of the furnace wall as a requirement of the method of repairing the damaged wall tube even if the furnace temperature does not fall to the specified temperature. Construction methods and equipment are required.
[0010]
There are two types of furnace wall pipes: a type in which the tubes are directly welded and a type in which a strip with a width of several tens of millimeters is inserted between the tubes and the strip is welded to the tube. Since there are welds in the direction, when welding from the outer surface, a groove that can be welded before the diameter is required.
[0011]
From these points, according to the present invention, when a part of the furnace wall pipe is damaged and ruptured, after removing the damaged part, a new pipe is inserted, and the circumferential joint part with the existing pipe is about 210 to 270 degrees. The inner wall is welded, and the remaining 150 to 90 degrees are welded to the outer surface. The outer wall of the furnace wall is sandwiched by the circumferential joint of the new tube inserted as an opening necessary for inner surface welding and the existing tube. Drill a hole in the range of about 150 to 90 degrees on the side, insert a welding torch from this opening, automatically TIG weld about 210 to 270 degrees from the inner surface of the pipe, and open the bead start and end after cleaning An insertion tube having an oval shape or the like matching the part is attached to the opening, and the periphery of the opening is welded by TIG welding.
[0012]
As a result, even if the boiler furnace wall pipe is damaged during operation, it can be repaired quickly and effectively.
[0013]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a conceptual diagram of a pipe repair welding method according to one embodiment of the present invention, FIG. 2 is a plan view of a pipe inner surface circumferential TIG welding state in the same method, and FIG. 3 is a pipe inner surface circle used in the same method. It is a side view of a circumference TIG welding apparatus. 4 (a) to 4 (c) are perspective views showing the procedure of the repair method, FIGS. 5 (a) to 5 (e) are plan views showing the pipe inner surface welding procedure of the repair method, and FIG. 6 shows the present invention. It is a figure which shows the example of damage of the furnace wall pipe to apply.
[0014]
In FIG. 1, after removing the damaged portion 21 shown in FIG. 6 generated in the furnace wall tube (existing tube) 01, a new tube 02 is inserted between the removed portions of the existing tube 01, and the respective welded portions are circumferentially welded. In this case, an opening 22 is formed on the outer wall side of the existing pipe 01 and the new pipe 02, and a small welding torch 06 shown in FIG. This shows a method of automatically welding the circumferential contact portion of the new tube 02 from the inner surface, and then attaching the insertion tube 03 suitable for the opening 22 and performing manual TIG welding on the periphery thereof. Note that 04 indicates an inner surface bead and 05 indicates an outer surface bead.
[0015]
FIG. 2 shows a welding situation in the cross section of the opening 22 provided on the outer wall side of the existing pipe 01 and the new pipe 02. The width of the opening 22 is about 90 to 150 ° in θ. Thus, the width is such that a small welding torch 06 or the like can be inserted.
[0016]
In addition, 04 is an inner surface bead, 07 is a tungsten electrode attached to the tip of the welding torch 06, and 20 is a guide nozzle for the welding wire.
[0017]
Further, the dimensions of the opening 22 in the tube axis direction are as shown in FIG. 3 for rotating the welding torch 06, the small slide 08 with arc voltage control, the motor 09 and the motor 09 along the circumferential direction of the tube. The support shaft 11 and the like are dimensioned to be inserted into the pipe inner surface.
[0018]
FIG. 3 is a schematic view of a pipe inner surface automatic TIG welding apparatus. In the figure, reference numeral 12 denotes an arm for supporting a welding torch 06 and a slide 08 inserted on the pipe inner surface on the pipe outer surface side, and is connected to the support shaft 11. The other end is connected to the rotating motor 13 of the welding torch 06, the welding wire feeder 19 and the like.
[0019]
14 is a transmission belt for rotating the welding torch 06, 08 is an electric slide for moving the welding torch 06 in the pipe radial direction, and has a control mechanism (not shown) for making the welding arc voltage constant, The rotational force of the motor 09 is transmitted to the slide 08 via a pair of spur gears 10 that mesh with each other, and the slide 08 is moved.
[0020]
Although the welding head such as the wire feeding device 19 on the outer surface of the pipe is not illustrated, it is fixed using a magnet or the like with the existing pipe 01 as a reference, and the welding head is moved in the pipe axis direction between the fixed portion and the welding head. Connect via the slide for position adjustment.
[0021]
Reference numeral 04 denotes an inner surface bead. Although not shown, a small-diameter fiberscope is attached in the vicinity of the welding torch 06 for monitoring a welding arc or a tungsten electrode 07.
[0022]
In the figure, 15 is a cable, 16 is a gas hose, 17 is a wire reel, 18 is a welding wire, and 20 is a wire guide nozzle.
[0023]
Next, the operation of the present invention will be described. In the present invention, when a part of the furnace wall tube 01 is damaged and ruptured as shown in FIG. 6, the damaged portion 21 is removed as shown in FIGS. Then, the new pipe 02 is inserted, the opening 22 is provided on the outer surface side of the furnace wall with the circumferential joint with the existing pipe 01, the automatic joint welding is performed from the inner surface of the pipe, and then the opening 22 is formed. The inserted insertion tube 03 is fitted and attached, and the elliptical joint portion of the insertion tube 03 is manually TIG welded.
[0024]
The procedure is shown in FIGS.
In FIG. 4, (a) is a state in which the circumferential joints of the existing pipe 01 and the new pipe 02 are welded from the inner surface, (b) is a state in which the insertion pipe 03 matching the opening 22 is temporarily attached, (c ) Shows the state where the elliptical joint of the insertion tube 03 is manually TIG welded.
[0025]
5A is a state in which the opening 22 is provided in the existing pipe 01, FIG. 5B is a state in which the small automatic TIG welding torch 06 is inserted into the existing pipe 01 from the opening 22, and FIG. The state where the welding torch 06 is positioned at the welding start point, (d) shows the state where the back wave welding of the first pass is finished, and (e) shows the state where the extra welding is finished and the welding torch 06 is removed.
[0026]
As described above, by this method, the damaged portion 21 of the furnace wall tube 01 can be repaired only from the furnace wall outer surface side.
[0027]
Although one embodiment of the present invention has been frequently described above, the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the technical idea of the present invention. Belongs to a range.
[0028]
【The invention's effect】
As described above, according to the pipe repair welding method and apparatus of the present invention, even if the boiler furnace wall pipe or the like of the power plant is damaged during operation, the furnace temperature can be quickly reduced without lowering to a predetermined temperature, and There is an effect that the damaged wall tube can be repaired at low cost.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a repair method according to an embodiment of the present invention.
FIG. 2 is a plan view of a pipe inner surface circumferential TIG welding situation in the same example.
FIG. 3 is a side view of the pipe inner surface circumferential TIG welding apparatus in the same embodiment.
4A, 4B, and 4C are perspective views showing the procedure of the repair method of the embodiment.
FIGS. 5A to 5E are plan views showing a pipe inner surface welding procedure of the repair method of the same embodiment.
FIG. 6 is a perspective view showing an example of damage to a furnace wall tube as a subject of the present invention.
[Explanation of symbols]
01 Furnace wall pipe (existing pipe)
02 New tube 03 Insertion tube 04 Inner surface bead 05 Outer surface bead 06 Welding torch 07 Tungsten electrode 08 Slide 11 Support shaft 12 Support arm 13 Rotating motor 14 Belt 15 Electric cable 16 Gas hose 17 Wire reel 18 Welding wire 19 Wire feeder 20 Wire guide nozzle 21 Damaged part 22 Opening part

Claims (2)

When repairing and welding a damaged boiler furnace wall tube during boiler operation, after cutting and removing the damaged portion of the damaged tube, a new tube is inserted, and the existing tube and the new tube are welded from the outside of the furnace wall As the above-mentioned existing pipe and the new pipe, the opening of only a small automatic TIG welding torch head is inserted into the inner surface of the furnace wall on the outer surface side of the circumferential groove, sandwiching the circumferential joint portion, First, automatic TIG welding is performed on the circumferential groove portion excluding the opening portion from the inner surface of the tube by the inserted welding torch, and then an insertion tube that fits the opening portion is temporarily attached to the opening portion, and then the insertion tube is temporarily attached. A repair welding method comprising performing manual TIG welding on the outer periphery of the attachment portion. Turning the small TIG welding torch and the guide nozzle and welding condition monitoring for fiber scope of the welding wire and miniature arc voltage control slide for moving the welding torch in the tube in a diameter direction to be inserted into the tube inner surface around the tube axis supported by possible rotation support arm, the support arm as well as to be inserted into the tube, the rotation motor of the welding torch connected to the rotary support arm outside the tube surface, the welding wire feeder and the welding wire coil It was placed, further wherein the welding torch turning unit pipe repair TIG welding apparatus characterized by a turning motor which is arranged on the rotary shaft and extravascular welding torch disposed in the tube and connected by belts as.

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