JP7216326B2 - PIPE WELDING METHOD AND PIPE WELDING DEVICE - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to a pipe welding method and a pipe welding apparatus suitable for use in, for example, repairing or newly installing pipes forming a furnace wall of a boiler.

Conventionally, for example, when a pipe that constitutes the furnace wall of a boiler is damaged, the damaged pipe is replaced with a new pipe, and the end of the new pipe is TIG-welded over the entire circumference to the existing pipe. I was trying to join.
This repair requires welding work from both the inside and outside of the furnace, and in particular, the inside of the furnace is welded after the scaffolding is assembled, so it takes a long time to repair and the repair cost is high. It was a bulky construction.

Conventionally, there is a welding method described in Patent Literature 1, for example, as a pipe repair welding method that has been made to compensate for such defects in construction at the time of pipe repair.

In this welding method, a new pipe is inserted into the removed part of the damaged pipe, and the new pipe is circumferentially welded to the existing pipe located at both ends. An opening is made in the surface of the pipe facing the outside of the furnace wall, and a small welding torch is inserted into the pipe through this opening to automatically weld the circumferential joint of the new pipe and the existing pipe from the inner surface of the pipe, An insertion tube matching the shape of the opening was attached to the opening by TIG welding.

JP-A-08-281468

However, in the conventional pipe repair welding method described above, the construction performed after automatic welding of the pipe inner surface of the circumferential joint of the new pipe and the existing pipe is a complicated construction such as attaching the insertion pipe to the opening by TIG welding. Therefore, a high skill is required to install this insertion tube.

In other words, the conventional pipe repair welding method described above has a problem that the welding quality depends on the welding skill of the operator, and solving this problem has been a conventional problem.

The present disclosure has been made in order to solve the above-described conventional problems. For example, when repairing piping that constitutes the furnace wall of a boiler, the repair period is shortened and the repair cost is reduced. Another object of the present invention is to provide a pipe welding method and a pipe welding apparatus capable of repairing a pipe with high welding quality regardless of the welding skill of the operator.

A first aspect of the present disclosure is a pipe welding method for joining pipes arranged in an axial direction, wherein the pipe is connected to at least one end of mutually continuous ends of the pipes arranged in the axial direction. An insertion portion penetrating in the radial direction is formed along the circumferential direction of the pipe for at most half the circumference, and the insertion portion is inserted from the outside of the pipe to the inner surface of the continuous end portion of the pipe where the insertion portion is not formed. After welding by irradiating a laser beam through the portion, the insertion portion of the pipe is closed by welding.

In addition, in a second aspect of the present disclosure, when one of the pipes arranged in the axial direction is a new pipe and the other is an existing pipe, the end of the new pipe that is continuous with the end of the existing pipe The insertion portion is formed in the portion in advance.

Furthermore, in a third aspect of the present disclosure, a laser beam is emitted from the outside of the pipe through the insertion portion to the inner surface of the continuous end portion of the pipe where the insertion portion is not formed, around the axis of the pipe. It is configured to irradiate while being rotated, and to irradiate while moving the laser light linearly at both ends of the insertion portion.

Furthermore, a fourth aspect of the present disclosure is configured such that a tab plate is temporarily attached to an end portion of the insertion portion during welding for blocking the insertion portion.

Furthermore, according to a fifth aspect of the present disclosure, a defocused laser beam is used to block the insertion portion.

Furthermore, according to a sixth aspect of the present disclosure, the insertion portion is closed using laser light from a laser diode having a linear or rectangular spot shape.

Furthermore, according to a seventh aspect of the present disclosure, the laser beam is oscillated to block the insertion portion.

Furthermore, according to an eighth aspect of the present disclosure, gas tungsten arc welding is used to block the insertion portion.

On the other hand, in the ninth aspect of the present disclosure, the radially penetrating portion is formed along the circumferential direction of at least one of the mutually continuous ends of the pipes arranged in the axial direction for at most half the circumference. A pipe welding device for joining the pipes arranged in the axial direction, wherein a laser beam is irradiated from the outside of the pipe through the insertion portion to the inner surface of the continuous end portion of the pipe where the insertion portion is not formed. a welding mechanism for closing the insertion portion of the pipe; and a drive mechanism for moving the laser head and the welding mechanism around the axis of the pipe , wherein the drive mechanism is configured to move the pipe and A concentrically arranged curved rail and a slider that holds the laser head and the welding mechanism and moves on the curved rail are provided, and the laser head irradiates the laser beam and moves along with the slider of the driving mechanism. By moving on a curved rail, a laser beam is rotated around the axis of the pipe and irradiated from the outside of the pipe through the insertion portion to the inner surface of the continuous end of the pipe for welding. there is

In the pipe welding method and the pipe welding apparatus of the present disclosure, the laser is generally a high-density laser such as a fiber laser, a disk laser, or a semiconductor laser, but is not limited to these lasers.

Using the pipe welding method according to the first aspect of the present disclosure, for example, when repairing a damaged pipe on the furnace wall of a boiler, first, after removing the damaged pipe, the removed pipe and Fit the new pipe between the existing pipes aligned in the axial direction.

At this time, on the surface located outside the furnace wall at at least one end of the mutually continuous ends of the existing pipe and the new pipe aligned in the axial direction, an insertion portion penetrating in the radial direction is formed in the circumferential direction of the pipe. forming at most half a circumference along.
This insertion portion may be formed when fitting a new pipe between existing pipes, or may be formed in a new pipe in advance like the pipe welding method according to the second aspect of the present disclosure. .

Next, a laser beam is irradiated from the outside of the pipe through the insertion part to the inner surface of the continuous end of the existing pipe and the new pipe where the insertion part is not formed, and the insertion part is closed by welding. This completes the joining of the new pipe to the existing pipe.

In this way, in the pipe welding method according to the first aspect of the present disclosure, since the welding work for repair is performed from the outside of the furnace wall, it is not necessary to build scaffolding inside the furnace, so the time spent on repair is unnecessary. As a result, the repair cost can be reduced.

In addition, in the pipe welding method according to the first aspect of the present disclosure, it is unnecessary to install an opening in the existing pipe and new pipe, which is required in the conventional pipe repair welding method, and TIG of the insertion pipe to this opening is eliminated. Since there is no need for complicated attachment work by welding, it is possible to perform repairs with high welding quality regardless of the welding skill of the operator.

According to the pipe welding method according to the present disclosure, for example, when repairing a damaged pipe, it is possible to shorten the repair period and reduce the repair cost, while achieving high welding performance without being affected by the welding skill of the operator. The very good effect of being able to perform quality repairs is provided.

1 is a perspective explanatory view schematically showing a pipe welding device used in a pipe welding method according to an embodiment of the present disclosure; FIG. 1. It is perspective explanatory drawing (a) which shows the existing piping and new piping which are joined by the piping welding apparatus of FIG. 1 along the axial direction, and expansion perspective explanatory drawing (b) which fracture|ruptures and shows a part of joining part. 1. It is cross-sectional explanatory drawing of a joint part which shows the condition which irradiates a laser beam through an insertion part from the outside of piping with respect to the inner surface of the edge part of piping in which the insertion part is not formed by the piping welding apparatus of FIG. 1. It is perspective explanatory drawing of the joint part which shows the condition which closes|closes the insertion part of piping by the piping welding apparatus of FIG. 1. It is cross-sectional explanatory drawing of the joint part at the time of block|closing the insertion part of piping with the piping welding apparatus of FIG. Longitudinal cross-sectional explanatory view (a) showing the state of the first layer at the joint portion when closing the insertion portion formed as a groove of the pipe by the pipe welding device of FIG. ). FIG. 11 is a perspective explanatory view of a joint portion showing a situation where a pipe insertion portion is blocked by a pipe welding device according to another embodiment of the present disclosure; FIG. 11 is a perspective explanatory view of a joint portion showing a situation where a pipe insertion portion is blocked by a pipe welding device according to still another embodiment of the present disclosure; FIG. 11 is a perspective explanatory view of a joint portion showing a situation where a pipe insertion portion is blocked by a pipe welding device according to still another embodiment of the present disclosure;

Hereinafter, embodiments of the present disclosure will be described based on the drawings.
FIG. 1 shows a pipe welding apparatus used in a pipe welding method according to an embodiment of the present disclosure, and this embodiment uses the pipe welding method of the present disclosure to repair damaged pipes in the furnace wall of a boiler. indicates the case.

As schematically shown in FIG. 1, this pipe welding device 1 is a pipe welding device for repairing damaged pipes on a furnace wall W of a boiler. The furnace wall W is constructed by arranging a large number of vertical pipes Pg in parallel so as to exchange heat with the heat source in the furnace, and the adjacent pipes Pg are connected to each other via fins F. It is connected.

This pipe welding apparatus 1 includes a laser oscillator 2, a laser head 4 that collects laser light L supplied from the laser oscillator 2 through an optical fiber 3 by an optical system, and the laser head 4 collects the light. It is equipped with a torch mirror 5 that bends the laser beam L by 90° and irradiates it toward the pipe P to be repaired, and a driving mechanism 10 for the laser head 4 and the torch mirror 5. The laser oscillator 2 includes a fiber laser or a disk. A high-density laser oscillator such as a laser or a semiconductor laser can be used.

The driving mechanism 10 includes fixed portions 11 welded to the fins F positioned on both sides of the pipe P to be repaired, chucks 12 supporting a new pipe PN, which will be described later, of the pipe P to be repaired, and the fixed portion 11. and a slider 14 that holds the laser head 4 and the torch mirror 5 and moves on the curved rail 13. A drive system for moving the slider 14 on the curved rail 13 includes, for example, a rack. A & pinion system may be employed, but is not limited to this.

Here, as shown in FIG. 2(a), the pipe P to be repaired is made by fitting a new pipe PN between the existing pipes PE, PE aligned in the axial direction after removing the damaged pipe. At the end Pa of the new pipe PN, as shown in FIG. 2(b), an insertion groove (insertion portion) Pt penetrating in the radial direction is formed over a little less than half the circumference along the circumferential direction.

The fixed part 11 of the driving mechanism 10 fixes the curved rail 13 so that the curved rail 13 can be concentrically arranged with the pipes PE, PN(P). The optical path) can be moved around the axis C of the pipes PE and PN(P) on the curved rail 13 while being parallel to the axis C of the pipes PE and PN(P).

That is, the laser beam L from the laser head 4 focused on the inner surface Ps of the end portions Pa, Pa of the pipes PE, PN(P) that are not formed with the insertion grooves Pt is bent by the torch mirror 5, In this state, the laser head 4 is moved along the curved rail 13 in the direction of the arrow in FIG. The inner surfaces Ps of the ends Pa, Pa can be irradiated from the outside of the pipe P through the insertion grooves Pt while the light is being emitted.

At this time, the laser head 4 is moved in the lower right direction in FIG. 3 By moving downward, welding of the inner surface Ps in the vicinity of the connecting portion between the pipe P and the fins F can also be performed. The mechanism for moving the laser head 4 with respect to the slider 14 may employ, for example, a rack and pinion system or a ball screw system, but is not limited to these.

In the pipe welding apparatus 1 of this embodiment, the laser head 4 can irradiate a defocused laser beam La as shown in FIG. head 4), and the defocused laser beam La emitted from the laser head 4 can be used to block the insertion groove Pt penetrating in the radial direction at the end Pa of the new pipe PN. It's becoming

At the time of welding for closing the insertion groove Pt, as shown in FIG. The crater generated at the end Pl (irradiation end of the laser beam La) is moved to the tab plate T. As shown in FIG.

In addition, at the time of welding when closing the insertion portion, as shown in FIG. ), the welding wire may be fed to the groove Pk to perform lamination.

When repairing a damaged pipe on the furnace wall W of a boiler using the pipe welding apparatus 1 described above, first, the damaged pipe (not shown) is removed, and then the pipe shown in FIG. A new pipe PN is fitted between the removed pipe and the existing pipes PE, PE aligned in the axial direction.

At this time, an insertion groove Pt through which the laser beam L can be inserted is formed along the circumferential direction of the new pipe PN in the surface positioned on the outer side of the furnace wall W at the end Pa of the new pipe PN (the front side in FIG. 2(b)). form at most half a circumference. For example, when the spot size θ of the laser beam L in FIG. 3 is 3°, the insertion groove Pt having a groove depth of about 1.5 mm is formed.
The insertion groove Pt may be formed when fitting the new pipe PN between the existing pipes PE, PE, or may be formed in the new pipe PN in advance.

Next, as shown in FIG. 1, the fixed portions 11, 11 in the drive mechanism 10 of the pipe welding device 1 are welded to the fins F, F located on both sides of the pipe P to be repaired, and a new pipe of the pipe P to be repaired is welded. A chuck 12 supports the PN.

Then, the laser head 4 of the pipe welding device 1 irradiates the laser beam L focused on the inner surface Ps of the end portions Pa, Pa of the pipes PE, PN(P) that are not formed with the insertion grooves Pt. is bent by the torch mirror 5.

In this state, the drive mechanism 10 is operated to move the laser head 4 along the curved rail 13 in the direction of the arrow in FIG. is rotated around the axis C of the piping P, and the inner surface Ps of the end portions Pa, Pa is irradiated with a laser beam L from the outside of the pipe P through the insertion groove Pt to perform welding.

Subsequently, at both ends of the curved rail 13 of the drive mechanism 10, the laser head 4 is moved (returned) toward the lower right in FIG. 3, welding of the inner surface Ps in the vicinity of the connecting portion between the pipe P and the fin F is also performed.

After welding to the inner surface Ps of the ends Pa and Pa and welding of the inner surface Ps in the vicinity of the connecting portion between the pipe P and the fin F, the end Pl of the insertion groove Pt is made of the same material as the pipe P or a welding material. After the tab plate T is temporarily attached, as shown in FIG. 4, a defocused laser beam La is irradiated from the laser head 4 to the ends Pa, Pa of the pipes PE, PN, thereby radially The joining of the new pipe PN to the existing pipe PE is completed by closing the insertion groove Pt.

Then, the repair of the pipe P is completed by performing the pipe welding performed on one end Pa of the new pipe PN also on the other end Pa.

As described above, with the pipe welding apparatus 1 according to this embodiment, since welding work for repair can be performed from the outside of the furnace wall W, it is not necessary to set up a scaffold inside the furnace, and the amount of time required for repair is eliminated. As a result, it is possible to reduce the number of repair costs.

In addition, in the pipe welding apparatus 1 according to this embodiment, it is not necessary to install an opening in the existing pipe and the new pipe, which is required in the conventional pipe repair welding method. Since complicated installation work is no longer required, high-quality welding can be repaired regardless of the welding skill of the operator.

In the pipe welding device 1 according to the above-described embodiment, the defocused laser beam La from the laser head 4 is used for welding by the welding mechanism that closes the insertion groove Pt penetrating in the radial direction. Alternatively, for example, as shown in FIG. 7, the insertion groove Pt may be closed using laser light Lb from a laser diode having a rectangular (or linear) spot shape.

Further, a mechanism for oscillating the torch mirror 5 is provided to oscillate the laser beam L from the laser head 4 to close the insertion groove Pt as shown in FIG. Instead of the laser head 4, a torch 17 for gas tungsten arc welding may be attached to the slider 14 of the mechanism 10, and the insertion groove Pt may be closed while the welding wire 18 is fed.

In the above-described embodiment, the insertion groove (insertion portion) Pt penetrating in the radial direction is formed at the end Pa of the new pipe PN. The insertion groove (insertion portion) Pt may be formed at the end Pa of the existing pipe PE, or may be formed across each end Pa of the existing pipe PE and the new pipe PN. A slit as an insertion portion may be formed at the end Pa of the .

Further, in the above-described embodiment, the pipe welding method of the present disclosure is used to repair damaged pipes in the boiler furnace wall. It may be used for newly installing piping at times.

Furthermore, in the above-described embodiment, the case where the pipe welding method of the present disclosure is adopted for pipes on the furnace wall of a boiler has been shown, but the pipe welding method of the present disclosure can be applied, for example, to a heat exchanger such as a superheater or a reheater. It may be used in equipment.

The configurations of the pipe welding method and pipe welding apparatus according to the present disclosure are not limited to the above-described embodiments, and can be variously modified without departing from the spirit of the invention.

1 pipe welding device 4 laser head (also a welding mechanism)
10 Drive mechanism C Piping axis L Laser beam La Defocused laser beam Lb Laser diode laser beam P Pipe to be repaired PE Existing pipe PN New pipe Pa Pipe end Pg part)
Ps inner surface Pt insertion groove (insertion portion)

Claims (9)

A pipe welding method for joining pipes arranged in an axial direction,
Forming at least one of the ends of the axially aligned pipes that are continuous with each other, an insertion portion penetrating the pipe in the radial direction along the circumferential direction of the pipe for at most half the circumference,
After welding by irradiating a laser beam from the outside of the pipe through the insertion portion to the inner surface of the continuous end portion of the pipe where the insertion portion is not formed,
A pipe welding method for closing the insertion portion of the pipe by welding. When one of the pipes arranged in the axial direction is a new pipe and the other is an existing pipe, the insertion portion is formed in advance at the end of the new pipe that is continuous with the end of the existing pipe. Item 1. The piping welding method according to Item 1. The inner surface of the continuous end portion of the pipe where the insertion portion is not formed is irradiated with a laser beam from the outside of the pipe through the insertion portion while rotating about the axis of the pipe, and the insertion portion 2. The pipe welding method according to claim 1, wherein the laser beam is irradiated while moving linearly at both ends of the. 2. The pipe welding method according to claim 1, wherein a tab plate is temporarily attached to an end portion of the insertion portion during welding for closing the insertion portion. The pipe welding method according to any one of claims 1 to 4, wherein the insertion portion is closed using defocused laser light. The pipe welding method according to any one of claims 1 to 4, wherein a laser beam of a laser diode having a linear or rectangular spot shape is used to close the insertion portion. The pipe welding method according to any one of claims 1 to 4, wherein the insertion portion is blocked by oscillating laser light. The pipe welding method according to any one of claims 1 to 4, wherein gas tungsten arc welding is used to close the insertion portion. Piping that joins the axially aligned pipes, in which a radially penetrating portion is formed along the circumferential direction of at least one of the mutually continuous ends of the axially aligned pipes for at most half the circumference A welding device,
a laser head for welding by irradiating a laser beam from the outside of the pipe through the insertion portion to the inner surface of the continuous end portion of the pipe where the insertion portion is not formed;
a welding mechanism that closes the insertion portion of the pipe;
A drive mechanism for moving the laser head and the welding mechanism around the axis of the pipe ,
The drive mechanism comprises a curved rail arranged concentrically with the pipe, and a slider that holds the laser head and the welding mechanism and moves on the curved rail,
The laser head moves on the curved rail together with the slider of the driving mechanism while irradiating the laser beam, thereby rotating the laser beam around the axis of the pipe and passing the laser beam from the outside of the pipe through the insertion portion. A pipe welding device for welding by irradiating the inner surface of the continuous ends of the pipe.

Images