JPH05185257A - Welding device for repairing small diameter pipe - Google Patents

Abstract

PURPOSE:To provide a welding device for repairing a small diameter pipe, in which the repairing can be executed from the inner part of the small diameter pipe and gap between the piping and an inner sleeve causing corrosion is difficult to develop and flow of fluid is not disturbed as less as possible. CONSTITUTION:In the piping by inserting the inner sleeve 10 having the shape thinning both opening ends into the piping 1 having the defect part 2 caused by damaging at the position, where the defect part in the piping exists in between both opening ends, after both opening ends are fixed by expanding the pipe, the inner sleeve and the piping are welded and also both ends of the inner sleeve are seal-joined 4 in the inner surface of the piping. Further, a clamp supporting part is inserted and fitted at a position exceeding the defect part in the piping, and after cutting and removing the piping having the defect part through the clamp supporting part, the welding work part is connected with the clamp supporting part through the new piping and this piping and also the new piping is welded and connected to the cut end of the piping. By this method, the repairing in the small diameter pipe without impairing the function of flow passage resistance, etc., is executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a repair work for a piping system, and more particularly to a repair welding device for a damaged defect portion in a small diameter pipe.

[0002]

2. Description of the Related Art Conventionally, when a small-diameter pipe is defective in a pipe of a nuclear reactor pipe or a heat exchanger, when repairing the small pipe, both ends of the pipe are stopped with a stopper. Alternatively, a method of inserting a pipe having an outer diameter substantially equal to the inner diameter of the pipe (hereinafter referred to as an inner sleeve) into the defective portion of the pipe and fixing it by expanding or welding to seal the defective portion is known. It has been implemented. This will be described with reference to FIGS. 11 to 13. When a defect 2 of the pipe 1 is found as shown in the cross-sectional view of FIG. 11, a tubular inner sleeve 3 is inserted into the pipe 1 and both sides of the defect 2 are inserted. Then, seam welding 4 is performed in the circumferential direction so as to penetrate through the inner surface sleeve 3 to join them. 12 is a sectional view of the inner sleeve 3.

The inner sleeve 3 is characterized by a shape with a constant wall thickness, and when fixed inside the pipe 1,
As shown in the sectional view of 13, the inner sleeve 3 is inserted so as to close the defect 2 of the pipe 1, the tube expander 5 is further inserted into the inner sleeve 3, and the central portion of the inner sleeve 3 is plastically deformed. The pipe is expanded and the inner sleeve 3 is fixed to the pipe 1. Then, seam welding is performed on both sides of the defect 2 to fix the pipe 1 and the inner sleeve 3, and the defect 2
To block.

[0004]

When repairing a pipe that is damaged and has a defect or the like, when the pipe is closed with a stopper, the number of pipes contributing to heat exchange in a heat exchanger, for example. However, it is not possible to use it when a large number of defective pipes are used. When the inner sleeve 3 is inserted, a gap 6 may be formed between the pipe 1 and the inner sleeve 3, and when the fluid flows in the pipe 1, the gap 6 may cause corrosion.
Furthermore, since the inner diameter of the pipe 1 is reduced by inserting the inner sleeve 3, the end portion of the inner sleeve 3 is not smooth,
There is a problem that the flow of the fluid is disturbed and the flow path resistance increases.

Further, when the pipe expander 5 expands the pipe to fix the cylindrical inner sleeve 3 in the pipe 1, a large force is applied to the defect 2 of the pipe 1 because the inner sleeve 3 is thick. Therefore, not only the inner sleeve 3 but also the pipe 1 itself may be deformed. Furthermore, in order to carry out repairs that do not cause the above problems, there is a method of cutting and removing the defective pipe and replacing the defective pipe with a new pipe. Since it is about 20 mm or less and many pipes are arranged around it, it is required to develop a repair device that can be inserted into a damaged small diameter pipe and can be replaced with a new pipe. It was

The first object of the present invention is to enable repair from the inside of a small-diameter pipe, to prevent a gap between the pipe and the inner surface sleeve which causes corrosion, and to prevent the flow of fluid from being disturbed as much as possible. The inner sleeve to be inserted into the pipe, the device in which the inner sleeve is welded and fixed in the pipe, and secondly, the pipe of the defective portion damaged by inserting into the pipe of a small diameter is cut and removed, and a new end is added to the cut end. An object is to provide a small diameter pipe repair welding device for welding and joining pipes.

[0007]

According to a first aspect of the present invention, an inner sleeve having a thin wall thickness at both open ends, and the inner sleeve is inserted into a damaged and defective pipe.
After fixing both open ends by expansion in the pipe at positions where both open ends sandwich the defective portion of the pipe, the inner sleeve and the pipe are welded, and both ends of the inner sleeve are sealed and joined to the inner face of the pipe.

According to the second aspect of the invention, a clamp guide having a cooling gas passage at the front end and a hydraulic seal portion extending in the circumferential direction, a hydraulic cylinder provided with a latch at the rear end, and the hydraulic cylinder. Freely rotate the piston and the hydraulic cylinder, which is provided with a processing portion coupling between a locking portion that locks with the latch of the hydraulic cylinder and a welded portion in the rear part that moves inside and expands the hydraulic sealing portion. And a clamp support portion composed of a welding processing portion insertion guide supported on the above, and a coupling for coupling the processing portion coupling of the clamp support portion with a cooling gas flow path at the tip end are rotatably provided, and a cylindrical tip end and It is characterized in that it comprises a welding processing part in which a laser welding device is provided inside a housing having a cooling gas flow path inside and a window opened on the outer periphery.

[0009]

According to the first aspect of the present invention, the inner surface sleeve having thin walls at both ends is inserted into the pipe, and the defective portion is sandwiched therebetween. Since the pipe expanding operation is performed on the thin portions at both ends, a large force is not required. Therefore, even when the thickness of the pipe is thin and the strength is small, the inner sleeve can be attached without hindering the pipe.
Furthermore, since the inner surface of the pipe and the end of the inner sleeve are sealed together with seam welding between the inner sleeve and the pipe, there is no gap between the pipe and the inner sleeve, resulting in corrosion and fluid disturbance in the pipe after repair. There is no increase in the flow path resistance.

According to the second aspect of the invention, the clamp support portion is inserted and installed at a position beyond the defective portion in the pipe, the pipe having the defective portion is cut and removed through the clamp support portion, and then a new one is provided. A pipe and a welded portion are connected to the clamp support through the pipe, and a new pipe is welded and connected to the cut end of the pipe. As a result, repairs can be performed without impairing functions such as flow path resistance in the small diameter pipe.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. It should be noted that the same components as those of the above-described conventional technique are designated by the same reference numerals and detailed description thereof will be omitted. FIG. 1 is a sectional view showing the constitution of the first invention, and FIG. 2 is a sectional view of an inner sleeve. As shown in FIG. 2, the inner sleeve 10 has a cylindrical shape and a cross-sectional shape in which the thickness at both open ends is thin. The inner sleeve 10 is usually made of the same material as the pipe 1. For example, if the pipe 1 is carbon steel, the inner sleeve 10 is also carbon steel. However, the materials of the pipe 1 and the inner sleeve 10 may be different, and for example, the pipe 1 may be carbon steel and the inner sleeve 10 may be stainless steel.

FIG. 3 is a sectional view showing that the inner sleeve is fixed in the pipe. After the inner sleeve 10 is inserted into the pipe 1 and the defect 2 is sandwiched between them, the tube expander 11 is placed inside the inner sleeve 10. Then, an expansion force is applied to the thin portions at both ends of the inner sleeve 10, and the inner sleeve 10 is mounted in the pipe 1 by utilizing the plastic deformation of the inner sleeve 10. The tube expander 11 is generally fixed at both ends at the same time, but may be fixed at each end. The deformation of the end portion of the inner sleeve 10 does not require excessive stress due to the thin portion, and therefore the inner sleeve 10 and the pipe 1 are not excessively deformed.

After the pipe expander 11 is pulled out, as shown in FIG. 1, seam welding 4 is performed to fix the defect 2 of the pipe 1 by an inner sleeve 10 mounted at a predetermined position in the pipe 1 and fixed. For this welding, the TIG welding method of welding using a tungsten electrode is used in an inert gas atmosphere. However, plasma welding method using plasma, laser beam welding method using laser, or electron beam welding method using electron beam is used. Is also good. After this, for example, seal welding 12 is performed so that the gap between both ends of the inner sleeve 10 and the inner surface of the pipe 1 is sealed, and the repair is completed.

The TIG welding method is used for the seal welding 12, but a plasma welding method, a laser welding method, or an electron beam welding method may be used. Pipe 1 with the above structure and construction, which has a small diameter and thin wall, and thus cannot obtain high strength.
Also, the inner surface sleeve 10
Can be inserted and fixed, and small diameter pipes that do not interfere with the flow of fluid can be repaired.

Next, as for the second invention, as shown in the front view showing the entire structure in the cut pipe of FIG. 4, a small-diameter pipe repair welding device comprising a clamp support portion 20 and a welded portion 30, FIG. 5 is a sectional view of the clamp support portion, and FIG. 6 is a sectional view of the welded portion. Clamp support
As shown in FIG. 5, 20 is a clamp guide 23 having a cooling gas passage 21 and a hydraulic seal portion 22 extending in the circumferential direction at the tip.
And a hydraulic cylinder 25 provided with a latch 24 around the rear end thereof, and a hydraulic fluid 25a advanced in the hydraulic cylinder 25 and compressed into the hydraulic cylinder 25 to compress the hydraulic fluid 25a through a passage 22a. 22 is expanded and is composed of a piston 26 mounted on the inner circumference of the pipe 1 shown in FIG.

Further, at the rear portion of the piston 26, an engaging portion 27 for engaging with the latch 24 of the hydraulic cylinder 25, and a welded portion.
A processing portion coupling 28 that fits and connects with 30 is provided. Furthermore, the hydraulic cylinder 25 is rotatably supported between the clamp guide 23 and a cylindrical welded portion insertion guide 29, which is partially notched, and a bearing 29a, for example.

As shown in FIG. 6, the welded portion 30 is provided with a cooling gas passage 21 at the tip thereof, and has a cylindrical coupling 31 for fitting and coupling with the processing portion coupling 28 of the clamp supporting portion 20. It is rotatably provided by, for example, a bearing 32a at the tip of a housing 32 having a cooling gas passage 21 at the tip and inside thereof. Further, the housing 32 has a laser radiation window 33 formed on the outer periphery of the front side, and a laser welding device including a mirror 34, optical lenses 35 and 35, and an optical fiber 36 is installed therein.

The laser welding device is provided with a laser beam 37 from a YAG laser or a CO ₂ laser generator, which is installed outside (not shown), introduced through an optical fiber 36, and passes through optical lenses 35, 35 and a mirror 34. housing
By rotating 32, 360 outside the laser emission window 33
It has a function of welding pipes by irradiating in the direction of the angle.

Next, the operation of the above configuration will be described. As shown in the front view in which a part of the pipe in FIG. 7 is cut,
For the pipe 1 in which the defect 2 has occurred, first the clamp support portion
20 is inserted into the inside, and is positioned forward (left in FIG. 7) from the position of the defect 2 by the welding processing portion insertion guide 29, and the processing portion coupling 28 is pushed by a push rod (not shown), so that the hydraulic cylinder 25 The latch 24 of the processing section coupling 28
It is locked to the locking portion 27 of. Piston 26 is hydraulic cylinder 25
The hydraulic fluid 25a therein is compressed through the passage 22a,
Hold the pressure of 25a. As a result, the hydraulic fluid 25a expands the hydraulic seal portion 22 and presses and fixes the clamp support portion 20 to the pipe 1.

Next, as shown in the front view of FIG. 8, a coupling which is fitted and connected to the processed portion coupling 28 at the tip thereof.
A pipe cutting device 40 provided with 41 is inserted into the pipe 1 and connected to the clamp support portion 20 to cut the pipe 1 at a position in front of the defect 2. The pipe cutting device 40 may be a grinder cutter that rotates a small grindstone, or an electric discharge machining device that works with the inside and outside of the pipe 1 filled with water. It should be noted that the pipe 1 having the defect 2 caused by the damage is taken out of the pipe cutting device 40 after the cutting is completed and the end portion thereof is fixed to the tube sheet 42 by the welding 43. After cutting, the pipe having the defect 2 is pulled out of the tube sheet 42.

Then, as shown in the front view of FIG.
The welding end face is processed by using, for example, a small grinder or an electric discharge machine (not shown). After this, a new pipe 45 whose welding groove is processed so that its tip matches the welding groove 44 of the pipe 1 is inserted, and after positioning by the welding processed portion insertion guide 29, the welding processed portion is positioned.
30 is inserted, and the coupling 31 at the tip thereof is connected to the processing portion coupling 28 of the clamp supporting portion 20.

In the welded portion 30, the laser light 37 introduced by the optical fiber 36 from a laser generator (not shown) is condensed by the optical lenses 35 and 35, and the mirror 34 irradiates the inner surface of the pipe 1 from the laser emission window 33. Then, the pipe 1 and the new pipe 45 are welded together at the welding groove 44, which is the joining point. Further, in the pipe 1 and the new pipe 45, and in the clamp support portion 20 and the welded portion 30 which are the small diameter pipe repair welding apparatus of the present invention, cooling gas is flowed through the cooling gas passage 21
The optical lenses 35, 35 and the mirror 34 are cooled.

The welding of the welding groove 44 is carried out by the housing
32 and the welded portion insertion guide 29 of the clamp support portion 20 are integrally locked by a not-shown locking portion, and the welded portion insertion guide 29 is rotated to weld the entire circumference of the pipe 1 and the new pipe 45. Weld groove 44. When the welding in the welding groove 44 is completed, the laser beam 37 is stopped and then the welding processing portion 30 is pulled out, and then a pipe inner surface polishing processing device (not shown) is separately attached to the processing portion coupling 28 of the clamp support portion 20 as necessary. It is possible to reduce the flow path resistance by polishing the portion of the weld groove 44 which is connected and welded to make the inner surfaces of the pipe 1 and the new pipe 45 smooth.

After pulling out the pipe inner surface polishing apparatus,
When the latch 24 of the clamp support portion 20 is released, the piston 26 is pushed back by the pressure of the hydraulic fluid 25a in the hydraulic cylinder 25,
Since the hydraulic seal portion 22 shrinks and is not fixed to the inner surface of the pipe 1, the clamp support portion 20 is pulled out of the new pipe 45, and then the end portion of the new pipe 45 is welded to the tube sheet 42.
After fixing, the repair of the pipe 1 having the defect 2 caused by the damage is completed. In the second aspect of the invention, all repair work is performed from the inside of the small diameter pipe, the defective portion is deleted together with the surrounding pipe, and a new pipe 45 is replaced, and the inner surface and the function thereof are almost the same as those of the original pipe. It can be similar to the state.

The first and second inventions have been described by way of examples for a heat exchanger in which a liquid is circulated in a small-diameter pipe as an embodiment. However, the present invention is applicable to the pipe and installation thereof. It can be implemented regardless of the structure and the like, and the operation and effect thereof can be the same as those of the above-described embodiments.

[0026]

As described above, according to the present invention, in the first invention,
Using the same tools and processing methods as in the past, it is possible to easily insert and fix the inner sleeve without damaging the pipe, even if the pipe has a small diameter and a thin wall that does not provide sufficient strength. There is an effect that it is possible to repair a small diameter pipe that does not hinder the flow of fluid as much as possible.

In the second aspect of the invention, no large-scale work such as disassembling or temporarily relocating the device in which the pipe is installed or the adjacent pipe is required, and the defective portion of the defective pipe can be replaced and repaired from within the small diameter pipe. It has an effect that it can be easily implemented, and functions such as flow path resistance and heat transfer efficiency can be maintained as in the conventional case.

[Brief description of drawings]

FIG. 1 is a structural cross-sectional view showing repair welding of a small diameter pipe by inserting an inner surface sleeve of the first invention.

FIG. 2 is a sectional view of an inner surface sleeve according to the first invention.

FIG. 3 is a cross-sectional view showing a construction situation of repairing a small diameter pipe by inserting an inner sleeve according to the first invention.

FIG. 4 is a front view in the pipe of the small diameter pipe repair welding device of the second invention.

FIG. 5 is a sectional view showing a configuration of a clamp support portion of a second invention.

FIG. 6 is a structural cross-sectional view of a welded portion of the second invention.

FIG. 7 is a front view showing a pipe supporting state by the clamp supporting portion of the second invention.

FIG. 8 is a front view showing the pipe cutting work of the second invention.

FIG. 9 is a front view showing a pipe welding groove state of the second invention.

FIG. 10 is a front view showing a pipe joining state of the second invention.

FIG. 11 is a structural cross-sectional view showing conventional small-diameter pipe repair welding by inserting an inner sleeve.

FIG. 12 is a sectional view of a conventional inner sleeve.

FIG. 13 is a cross-sectional view showing a construction situation of conventional small-diameter pipe repair by inserting an inner sleeve.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Piping, 2 ... Defect, 4 ... Seam welding, 10 ... Inner surface sleeve, 11 ... Tube expander, 12 ... Seal welding, 20 ... Clamp support part, 21 ... Cooling gas flow path, 22 ... Liquid pressure seal part, 22a ... Passage, 23 ... Clamp guide, 24 ... Latch, 25 ... Hydraulic cylinder, 25a ... Hydraulic fluid, 26 ... Piston, 27 ... Locking part, 28 ... Working part coupling, 29 ... Welding part insertion guide, 29a,
32a ... Bearing, 30 ... Welded part, 31,41 ... Coupling,
32 ... Housing, 33 ... Laser emission window, 34 ... Mirror, 35 ...
Optical lens, 36 ... Optical fiber, 37 ... Laser light, 40 ... Pipe cutting device, 42 ... Tube plate, 43 ... Welding, 44 ... Welding groove, 45 ...
New plumbing.

Claims (2)

[Claims] 1. An inner sleeve having a shape that is thin at both open ends, and the inner sleeve is inserted into a damaged and defective pipe, and both open ends sandwich a defective portion of the pipe. 2. A small-diameter pipe repair welding device, characterized in that after fixing both open ends in the pipe by expanding the pipe, the inner sleeve and the pipe are welded and both ends of the inner sleeve are sealed and joined to the inner surface of the pipe. 2. A clamp guide having a cooling gas flow path at its front end and a hydraulic pressure seal portion extending in the circumferential direction, a hydraulic pressure cylinder having a latch at its rear end, and a hydraulic cylinder moving in the hydraulic pressure cylinder. Welding process that rotatably supports the piston and the hydraulic cylinder, which is provided with a processing part coupling between a locking part that engages with the latch of the hydraulic cylinder and a welding process part in the rear part that extends the hydraulic sealing part. Part and a clamp support part consisting of a part insertion guide, and a coupling for connecting the processing part coupling of the clamp support part with a cooling gas flow path at the tip is rotatably provided. A small-diameter pipe repair welding device, comprising: a welding process part provided with a laser welding device inside a housing having a passage and a window on the outer circumference.