JP2014030843A - Pipe end welding method, air-cooling type heat exchanger and manufacturing method of air-cooling type heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipe end welding method capable of welding a pipe end on an inner surface side surface of a side plate, by supporting an object on the support cylinder tip without run-out, even if the support cylinder tip of a pipe end automatic welder is not inserted into a pipe hole of a welding part.SOLUTION: The present invention is provided with means having a support cylinder 12, and preparing a pipe end automatic welder 10 capable of detachably installing a guide member 15 even in any of both sides of the support cylinder 12. A heat transfer pipe 3 is inserted into the pipe hole 4, and is pushed in until an end part 3a reaches an inside surface 2a1 of a side plate 2a. Next, the guide member 15 is installed in the pipe end automatic welder 10. Next, the support cylinder 12 is inserted from a plug hole 5 corresponding to the pipe hole 4 of a welding part, and is pushed in until the tip reaches this side vicinal position of the pipe hole 4, and the guide member 5 is inserted from a laterally adjacent plug hole 5 of the plug hole 5 corresponding to the pipe hole 4 of the welding part, and is pushed in until the tip reaches the inside of the pipe hole 4 corresponding to the plug hole 5. Next, the pipe end is welded in an inside surface position of the side plate 2a by an arc from a welding torch 13.

Description

  The present invention relates to a tube end welding technique performed in order to join a large number of heat transfer tubes to a box-shaped header in the manufacturing process of an air-cooled heat exchanger.

  Usually, in the heat exchanger manufacturing process, a large number of heat transfer tubes and tube support plates (referred to as tube plates) are joined together, so that the outer periphery of the end of each heat transfer tube and the tube through which the heat transfer tubes are inserted. A welding operation called pipe end welding in which the peripheral edges of the holes of the plate are circumferentially welded is performed (see Patent Document 1 below).

  On the other hand, in an air-cooled heat exchanger, a header is assembled in a box shape in advance, and a number of heat transfer tubes are welded to the box header to join the heat transfer tubes and the box header. Hereinafter, with reference to FIG.8 and FIG.9, the pipe end welding operation | work in an air-cooling type heat exchanger is demonstrated. A large number of tube holes 102 are formed in one side plate 101 of the box-shaped header 100, and a large number of plug holes 104 are formed in the other side plate 103 of the box-shaped header 100. At the time of pipe end welding, the support tube 106 of the pipe end automatic welder 105 is inserted into the plug hole 104 and the pipe hole 102 of the part to be welded. At this time, the tip of the support cylinder 106 is inserted from the inner surface 101a of the side plate 101 to a position recessed about 10 mm, for example. In such a state, the support cylinder 106 is supported at two points: the plug hole 104 and the tube hole 102. In such a support state, a welding torch (not shown) including a tungsten electrode provided inside the tip of the support tube 106 is rotated around the axis of the support tube 106 to weld the periphery of the heat transfer tube 108. It is carried out. In FIG. 8, reference symbol A indicates a welded portion.

  For reference, when manufacturing an air-cooled heat exchanger, first, a large number of heat transfer tubes 108 are welded to the side plate 101, and then a plurality of metal plates including the side plate 101 are welded to form a box. It is also possible to assemble the mold header 100. With such a method, welding work is easier compared to the method of pipe end welding after box-shaped header assembly. However, in the case of an air-cooled heat exchanger, the method of pipe end welding after assembling a box-type header cannot be employed for the following reason. That is, the header of the air-cooled heat exchanger is required to be subjected to post-weld stress relief heat treatment in accordance with laws and regulations (high-pressure gas safety law). Therefore, if pipe end welding is performed first, heat treatment of the welded portion of the header itself cannot be performed, and there is a risk of leakage due to stress corrosion cracking or the like during use of the air-cooled heat exchanger. Therefore, at present, the header is manufactured by welding, and after the header is subjected to stress relief heat treatment, the heat transfer tube is attached and the end of the tube is welded.

JP 2006-75870 A

  In the conventional example, pipe end welding is performed at a position recessed by about 10 mm from the inner surface 101 a of the side plate 101. In such welding at the pipe end position, it is necessary to increase the thickness of the side plate 101 of the box-shaped header 100. In particular, when a high-grade material such as titanium or incoloy is used as a material for the box-shaped header 100 or the heat transfer tube 108 to prevent corrosion, the cost becomes high. Therefore, it is required to reduce the cost by reducing the thickness of the side plate by performing pipe end welding on the inner surface of the side plate.

  However, if pipe end welding is to be performed on the inner surface 101a of the side plate 101 in order to meet the above requirements, the tip of the support tube 106 is pulled out from the tube hole 102, and the tip of the support tube 106 is supported at a position near the tube hole 102. It is necessary to let However, when the tip of the support tube 106 is pulled out from the tube hole 102, the support tube 106 is supported only at one point of the plug hole 104 and is supported at two points of the tube hole 102 and the plug hole 104. Compared to the conventional example, the support cylinder 106 is uneasy to be supported, and the welding torch at the tip of the support cylinder 106 is shaken, and accurate circumferential welding cannot be performed.

  Therefore, the pipe end welding on the inner surface of the side plate 101 in the box-shaped header 100 currently performed is not automatic welding using a pipe end automatic welding machine, but a welding machine is inserted from the plug hole 104, Manual welding is performed manually by visually observing the welded portion through another plug hole 104.

  It is to be noted that a shaft end metal jig is provided at the tip of the shaft as in Patent Document 1, and a tube end automatic welding machine in which a welding torch is arranged on the rear side of the shaft alignment core metal jig is used to If the alignment cored bar jig is inserted into the heat transfer tube, it is supported by two points, that is, the distal end part by the axis alignment cored bar jig and the base end part by the shaft, so that the tube on the inner surface 101a by the welding torch It seems possible to do end welding. However, in reality, since the welding torch is disposed outside the shaft, the welding torch cannot be inserted from the plug hole 104. Of course, if the diameter of the plug hole 104 is extremely large, the welding torch can be inserted from the plug hole 104, but the diameter of the plug hole 104 of the box-type header 100 of the actual air-cooled heat exchanger is not so large. It is a reality that cannot be inserted. Therefore, it is not possible to perform pipe end welding of the box-shaped header 100 using a pipe end automatic welder as in Patent Document 1. In addition, when a pipe end automatic welder such as that disclosed in Patent Document 1 is used, a part of the pipe end welded portion may hang down on the outer peripheral surface of the shaft, which makes it difficult to pull out the shaft. .

  The present invention has been conceived in view of the above problems, and its purpose is to sway the tip of the support tube without inserting the tip of the support tube of the automatic pipe end welder into the tube hole of the welded portion. The tube end welding method that enables the tube end welding to be performed on the inner surface of the side plate, the method of manufacturing the air cooling heat exchanger using the tube end welding method, and the air cooling type It is to provide a heat exchanger.

  In the present invention, one side plate of a pair of opposed side plates has a plurality of tube holes in a predetermined arrangement, and the other side plate has a plurality of tube holes in the same arrangement as the tube holes corresponding to the tube holes. In a box-shaped header in which plug holes are formed, plug holes corresponding to the tube holes of the portions to be welded when the end portions of the heat transfer tubes are inserted into the respective tube holes and the respective heat transfer tubes are sequentially welded to the tube ends. A pipe end automatic welder is inserted into the tube, and pipe end welding is performed with a welding torch provided at the tip of the support cylinder, the pipe end automatic welder serving as a guide extending in parallel with the support tube Prepare a pipe end automatic welder configured so that members can be detachably attached, insert the heat transfer tube into the tube hole, and until the end of the heat transfer tube reaches the inner surface of the one side plate The first step of pushing, and the support tube of the pipe end automatic welding machine is plugged Prior to insertion, a second step of mounting the guide member on a pipe end automatic welder, and inserting a support tube of the pipe end automatic welder from a plug hole corresponding to a pipe hole of a portion to be welded, A third step of pushing in until the tip of the support tube reaches a position in the vicinity of the front side of the tube hole, and the guide member corresponds to the tube hole of the portion to be welded in association with the push-in operation of the support tube in the third step. A fourth step that is inserted through a plug hole other than the plug hole and pushed until the tip of the guide member reaches the inside of the tube hole corresponding to the plug hole, and an arc from a welding torch provided at the tip of the support cylinder And a fifth step of performing pipe end welding at the inner surface position of the one side plate.

  As described above, the guide tube is inserted by inserting the support tube of the pipe end automatic welder from the plug hole corresponding to the tube hole to be welded, and pushing the tip of the support tube until the position near the front side of the tube hole. The member is inserted from a plug hole other than the plug hole corresponding to the pipe hole of the portion to be welded, and pushed in until the tip of the guide member reaches the pipe hole corresponding to the plug hole. Thereby, the support cylinder is supported and fixed by the plug hole, and in addition, is supported and fixed by the tube hole and the plug hole by the guide member. Therefore, the support state of the support cylinder is stable, the tip of the support cylinder is not shaken, and the stable support state is maintained. As a result, even if the tip of the support tube of the automatic pipe end welder is not inserted into the tube hole of the part to be welded, the tip of the support tube is supported in a stable and stable state, and the tube end welding is performed on the inner surface of the side plate. It can be performed.

  Further, according to the present invention, one side plate of a pair of opposing side plates has a plurality of tube holes formed in a predetermined arrangement, and the other side plate has the same arrangement as the tube holes corresponding to the tube holes. It has a pair of box-shaped headers in which a large number of plug holes are formed, and both ends of a large number of heat transfer tubes connecting the pair of box-shaped headers are inserted into the tube holes of each box-shaped header. An air-cooled heat exchanger having the above structure, wherein both ends of each heat transfer tube are automatically welded at the inner surface position of each header, and each heat transfer tube is supported and fixed to each header. .

  According to the above configuration, the thickness of the header can be reduced as compared with the conventional example, so that the material cost can be reduced. In particular, when using high-grade materials (for example, titanium and incoloy), the merit is great.

  In the air-cooled heat exchanger according to the present invention, the ratio of the diameter of the tube hole to the diameter of the plug hole may be within a range of 1.00: 1.01 to 1.00: 1.50.

  In addition, the present invention is a method of manufacturing an air-cooled heat exchanger including a pair of box-type headers and a large number of heat transfer tubes connecting between the pair of box-type headers. A box-shaped header in which a large number of tube holes are formed in one side plate in a predetermined arrangement, and a plurality of plug holes are formed in the other side plate in the same arrangement as the tube holes corresponding to the tube holes. And a step of automatically welding the end portions of a large number of heat transfer tubes at the inner surface position of the box-shaped header produced by the header production step.

  With the above configuration, pipe end welding is automatically performed at the inner surface position of the box-shaped header, so that workability is improved and accuracy variation is eliminated as compared with the case where it is manually performed as in the prior art. A highly accurate air-cooled heat exchanger can be obtained.

  In the method for manufacturing an air-cooled heat exchanger according to the present invention, the automatic pipe end welding step includes a support cylinder having a welding torch at the tip, and a detachable guide member extending in parallel with the support cylinder. Prepare an automatic welder, insert the heat transfer tube into the tube hole, push the end of the heat transfer tube until it reaches the inner surface of the one side plate, and plug the support tube of the tube end automatic welder Prior to insertion from the hole, a second step of mounting the guide member on the automatic pipe end welder and a support tube of the automatic pipe end welder are inserted from the plug hole corresponding to the pipe hole of the portion to be welded. A third step of pushing in until the tip of the support tube reaches a position near the near side of the tube hole, and the guide member is inserted into the tube hole of the portion to be welded in accordance with the pushing operation of the support tube in the third step. Plug hole other than the corresponding plug hole A fourth step that is inserted and pushed until the tip of the guide member reaches the inside of the tube hole corresponding to the plug hole, and an inner surface position of the one side plate by an arc from a welding torch provided at the tip of the support cylinder And 5th step of performing pipe end welding.

  As described above, in the manufacturing method using the pipe end automatic welder as in Patent Document 1, a part of the pipe end welded part hangs down on the outer peripheral surface of the shaft (corresponding to the support cylinder of the present invention), There is a problem that it becomes difficult to pull out. In this regard, in the present invention, since the tip of the support tube is not inserted into the tube hole of the portion to be welded, even if the tube end welded portion hangs down, there is an advantage that there is no problem in pulling out the support tube.

  According to the pipe end welding method of the present invention, the support cylinder is supported and fixed by the plug hole, and in addition, is supported and fixed by the pipe hole and the plug hole by the guide member. Therefore, the support state of the support cylinder is stable, the tip of the support cylinder is not shaken, and the stable support state is maintained. As a result, pipe end welding is performed on the inner surface of the side plate by supporting the tip of the support cylinder in a stable state without shaking, without inserting the tip of the support cylinder of the automatic pipe end welder into the pipe hole of the welded part. It can be carried out.

  In addition, according to the air-cooled heat exchanger of the present invention, both ends of each heat transfer tube are welded to the end of the inner surface of each header, thereby reducing the thickness of the header compared to the conventional example. Therefore, the material cost can be reduced.

  In addition, according to the method for manufacturing an air-cooled heat exchanger of the present invention, since the pipe end welding is automatically performed at the inner surface position of the box-shaped header, compared with the case where it is manually performed as in the prior art. Thus, an air-cooled heat exchanger with improved workability and uniform accuracy can be obtained.

The front view of the air-cooling type heat exchanger manufactured using the pipe end welding method which concerns on this invention. The disassembled perspective view of the header vicinity provided in an air-cooled heat exchanger. The disassembled perspective view of the header vicinity seen from the direction opposite to FIG. The longitudinal cross-sectional view of the header with which an air-cooling type heat exchanger is equipped. The figure for demonstrating the definition of hole efficiency. The cross-sectional view which shows the state by which the pipe end automatic welder was inserted in the header. The longitudinal cross-sectional view which shows the state by which the pipe end automatic welder was inserted in the header. The figure for demonstrating the pipe end welding method of a prior art example. FIG. 9 is a partially enlarged view of FIG. 8.

Hereinafter, the present invention will be described in detail based on embodiments. Note that the present invention is not limited to the following embodiments.
1 is a front view of an air-cooled heat exchanger manufactured by using the pipe end welding method according to the present invention, FIG. 2 is an exploded perspective view of the vicinity of a header provided in the air-cooled heat exchanger, and FIG. Is an exploded perspective view of the vicinity of the header as seen from the opposite direction, and FIG. 4 is a longitudinal sectional view of the header provided in the air-cooled heat exchanger. The air-cooled heat exchanger 1 according to the present embodiment is manufactured by an automatic pipe end welding method using a pipe end automatic welder, as will be described later. The air-cooled heat exchanger 1 includes a pair of box-shaped headers 2 and 2 and a number of finned heat transfer tubes (so-called fin tubes) 3 connecting the pair of headers 2 and 2. In one side plate 2a (a side plate on the opposite side of the pair of box-type headers 2) of the pair of side plates 2a and 2b in the header 2, as shown in FIG. Are arranged in a shape. In the present embodiment, the tube holes 4 are arranged in a staggered pattern, but the present invention is not limited to this, and may be, for example, a grid pattern or other arrangements. The end 3a of the heat transfer tube 3 is inserted into each tube hole 4, and the end 3a is welded to the end of the tube. Thereby, the many heat exchanger tubes 3 are supported and fixed to the side plate 2a.

  It should be noted here that the pipe end welding position is such that the pipe end welding is performed on the inner surface 2a1 of the side plate 2a. In FIG. 4, reference symbol A indicates a welded portion. Thereby, since the thickness of the side plate 2a can be reduced, the material cost can be reduced. In particular, when using high-grade materials (for example, titanium and incoloy), the merit is great. In addition, since the heat transfer tube 3 can be easily peeled off when the heat transfer tube 3 is replaced, the workability of the replacement operation is improved.

  In addition, as shown in FIG. 3, a number of plug holes 5 are formed in advance in the same arrangement as the tube holes 4 in the other side plate 2 b of the header 2 corresponding to the tube holes 4. A screw is cut on the inner peripheral surface of the plug hole 5, and a screw portion of the plug 6 is screwed.

  Here, the diameter of the tube hole 4 is in the range of 20 mm to 40 mm. The diameter of the plug hole 5 is in the range of 25 mm to 50 mm. The ratio of the diameter of the tube hole 4 to the diameter of the plug hole 5 is in the range of 1.00: 1.01 to 1.00: 1.50, preferably 1.00: 1.08 to 1.00: 1. .25 range. The reason for regulating the diameter of the plug hole 5 and the ratio of the diameter of the plug hole 5 to the diameter of the tube hole 4 as described above is as follows. That is, when the diameter of the plug hole 5 is too large, the strength of the header 2 is reduced, and to eliminate this, it is necessary to increase the plate thickness of the side plate 2b, which increases the material cost.

  On the other hand, when the diameter of the plug hole 5 is too small, it is difficult to perform the exchange operation of the heat transfer tube 3. More specifically, when the heat transfer tube 3 is exchanged, it is necessary to remove the plug 6 from the plug hole 5 and remove the weld metal with a cutting tool such as a cutter. At this time, if the diameter of the plug hole 5 is too small, the welded portion of the pipe end cannot be sufficiently observed, and the weld metal cannot be completely removed. Therefore, the end of the heat transfer tube 3 is peeled off from the side plate 2a. This is because it becomes difficult.

Therefore, the ratio of the diameter of the plug hole 5 and the diameter of the plug hole 5 with respect to the diameter of the tube hole 4 comprehensively takes into consideration the strength and material cost of the header 2 and the workability when replacing the heat transfer tube 3. Is set to the optimal range.
The hole efficiency of the tube hole 4 is in the range of 45% to 70%, preferably in the range of 52% to 64%. The opening ratio of the plug hole 5 is in the range of 40% to 65%, preferably in the range of 45% to 60%. Here, the hole efficiency is represented by hole efficiency (%) = {(pd) / p} × 100, where the hole pitch is p and the hole diameter is d, as shown in FIG. .

  FIG. 6 is a transverse cross-sectional view showing a state where the pipe end automatic welder is inserted into the header, and FIG. 7 is a longitudinal cross-sectional view showing a state where the pipe end automatic welder is inserted into the header. With reference to FIG.6 and FIG.7, the structure of the pipe end automatic welder used in this Embodiment is demonstrated. The automatic pipe end welder 10 includes an automatic pipe end welder main body 11 and an elongated support cylinder 12 connected to the main body 11. A rotating shaft (not shown) is inserted into the support cylinder 12, and a welding torch (not shown) including a tungsten electrode is provided at the tip of the rotating shaft. The tungsten electrode is disposed so as to be inclined in a direction away from the axis of the rotating shaft as it goes toward the tip side. Accordingly, the rotation of the rotating shaft causes the welding torch to rotate about the axis of the rotating shaft (which is also the axis of the support cylinder 12), thereby moving the arc from the tungsten electrode along the circumference of the tube hole 4. The tube end can be welded. In addition, the structure which automatically supplies the welding wire as a filler material may be included.

  Attachment portions 14 are provided on the left and right sides of the main body 11, respectively. A longitudinal guide member 15 is detachably attached to the attachment portion 14. The guide member 15 has a main body portion 15 a that can be inserted through the plug hole 5, and a tip portion 15 b that is smaller in diameter than the main body portion 15 a and can be inserted into the heat transfer tube 3 inserted into the tube hole 4. The guide member 15 extends in parallel to the support cylinder 12 when mounted on the mounting portion 14, and is adjacent to the plug hole 5 when the support cylinder 12 is inserted into the plug hole 5. The distance from the support cylinder 12 is set in advance so that it can be inserted into the plug hole 5. When performing pipe end welding, when the heat transfer tube 3 is welded to the tube hole 4 adjacent to the tube hole 4 of the welded portion, the tip of the guide member 15 is inserted into the heat transfer tube 3. The support state of the support cylinder 12 may be stabilized, and when the heat transfer tube 3 is not welded to the tube hole 4 adjacent to the tube hole 4 of the welded portion, the adjacent tube hole 4. The support member 12 may be stabilized by inserting the tip of the guide member 15 therein. In the latter case, the tip portion 15b is not necessarily smaller in diameter than the main body portion 15a, and conversely, the tip portion 15b may be larger in diameter than the main body portion 15a. In short, the distal end portion of the guide member 15 in the tube hole 4 adjacent to the tube hole 4 of the portion to be welded (in the heat transfer tube 3 when the heat transfer tube 3 is first welded to the adjacent tube hole 4). It is sufficient if 15b can be inserted to stabilize the support state of the support tube 12 for pipe end welding.

Next, a pipe end welding method performed in the manufacturing process of the air-cooled heat exchanger having the above configuration will be described. In the following pipe end welding method, the tip end portion 15b of the guide member 15 is inserted into the pipe hole 4 adjacent to the pipe hole 4 of the part to be welded, and the support cylinder 12 is in a support state for pipe end welding. An example of stabilization is shown.
First, prior to inserting the support cylinder 12 from the plug hole 5, the guide member 15 is mounted on either the left or right side of the pipe end automatic welder main body 11. For example, when pipe end welding is sequentially performed from the left end to the right end of the inner surface 2a1 of the side plate 2a, the guide member 15 is attached to the right mounting portion 14 of the pipe end automatic welder main body 11.

  Next, the support tube 12 of the pipe end automatic welder is inserted from the plug hole 5 corresponding to the tube hole 4 to be welded, and is pushed in until the tip of the support tube 12 reaches a position near the front side of the tube hole 4. By the pushing operation of the support cylinder 12, the guide member 15 is inserted from the plug hole 5 on the right side of the plug hole 5 through which the support cylinder 12 is inserted, and the tip 15 b is adjacent to the right side of the pipe hole 4 of the portion to be welded. Until it reaches the inside of the tube hole 4. As a result, the support cylinder 12 is supported and fixed by the plug hole 5 and, in addition, is supported and fixed by the tube hole 4 and the plug hole 5 by the guide member 15. Therefore, the support state of the support cylinder 12 is stable, the tip of the support cylinder 12 is not shaken, and the stable support state is maintained.

Next, pipe end welding is performed on the inner side surface 2a1 of the side plate 2a by an arc from a welding torch provided at the tip of the support cylinder 12. At this time, as described above, the tip of the support cylinder 12 does not shake and is in a stable support state, so that welding along the circumference can be performed accurately.
Thus, when the pipe end welding for one pipe is completed, the support cylinder 12 and the guide member 15 are pulled out, the pipe end automatic welder is moved side by side, and then the same processing as described above is performed.

When pipe end welding of the rightmost heat transfer tube 3 is performed, the guide member 15 is attached to the left mounting portion 14 of the pipe end automatic welder main body 11. As a result, the guide member 15 is inserted from the plug hole 5 adjacent to the left side of the plug hole 5 at the right end, and the tip 15b of the guide member 15 is mounted in the tube hole 4 adjacent to the left side of the pipe hole 4 of the welded portion. It is pushed into the heat pipe 3. Moreover, after completion | finish of the said row of pipe end welding work of the said horizontal direction, it transfers to an upper stage or a lower stage, and the same operation | work is performed. Thus, one end of many heat transfer tubes 3 is supported and fixed to the side plate 2a, and the other end of many heat transfer tubes 3 is supported and fixed to the side plate 2b.
In addition, the plug 6 is attached to the plug hole 5 and is tightened with a tightening torque that does not leak, the plug hole 5 is sealed, and the air-cooled heat exchanger 1 is obtained.

  In the above example, when pipe end welding of the right end heat transfer tube 3 is performed, the guide member 15 is mounted on the left side mounting portion 14 of the pipe end automatic welder main body 11, but the guide member 15 is automatically welded to the pipe end. The pipe end automatic welder main body 11 may be rotated 180 degrees and the guide member 15 may be positioned on the left side in a state in which the pipe end automatic welder main body 11 is attached to the right mounting portion 14 of the machine main body 11.

  When the heat transfer tube 3 at the center position excluding the right end or the left end is welded to the tube end, two guide members 15 are prepared, and these guide members 15 are attached to the left and right sides of the tube end automatic welder main body 11. They may be respectively attached to the portions 14 and inserted into the plug holes 5 adjacent to the left and right sides of the plug hole 5 through which the support cylinder 12 is inserted. In this way, the number of support points is further increased, and the support state of the support cylinder 12 can be further stabilized.

(Other matters)
In the said embodiment, although the heat exchanger tube 3 with a fin was used, you may use the heat exchanger tube 3 without a fin.
In the above embodiment, the guide member 15 is configured to be detachably mounted on both the left and right sides of the support cylinder 12. However, the guide member 15 is configured to be detachably mounted on the upper and lower sides of the support cylinder 12. May be. In this case, the guide member 15 is inserted into the plug hole 5 diagonally adjacent to the plug hole into which the support cylinder 12 is inserted.
Further, in the above embodiment, the guide member 15 is configured to be inserted into the plug hole 5 adjacent to one of the plug holes into which the support cylinder 12 is inserted. It may be configured to be inserted into the hole 5.

  The present invention can be applied to a pipe end welding method for an air-cooled heat exchanger.

1: Air-cooled heat exchanger 2a, 2b: Side plate 2a1: Inner surface of side plate 2a 3: Heat transfer tube 4: Tube hole 5: Plug hole 6: Plug 10: Pipe end automatic welder 12: Support tube 14: Mounting portion 15 : Guide member

Claims (5)

One side plate of a pair of opposing side plates has a plurality of tube holes formed in a predetermined arrangement, and the other side plate has a plurality of plug holes formed in the same arrangement as the tube holes corresponding to the tube holes. When the end of the heat transfer tube is inserted into each tube hole and the respective heat transfer tubes are sequentially welded to the tube end, the tube end is automatically inserted from the plug hole corresponding to the welded portion of the tube header. A method of inserting a support cylinder of a welding machine and performing pipe end welding with a welding torch provided at the tip of the support cylinder,
As the pipe end automatic welder, a pipe end automatic welder configured to be detachably mounted with a guide member extending in parallel with the support cylinder,
A first step of inserting the heat transfer tube into the tube hole and pushing in until the end of the heat transfer tube reaches the inner surface of the one side plate;
A second step of attaching the guide member to the pipe end automatic welder prior to inserting the support tube of the pipe end automatic welder from the plug hole;
A third step of inserting the support tube of the pipe end automatic welder from a plug hole corresponding to a tube hole of a portion to be welded, and pushing in until the tip of the support tube reaches a position near the near side of the tube hole;
Along with the pushing operation of the support cylinder in the third step, the guide member is inserted from a plug hole other than the plug hole corresponding to the tube hole of the welded portion, and the tip of the guide member corresponds to the plug hole. A fourth step that is pushed into the bore,
A fifth step of performing pipe end welding at an inner surface position of the one side plate by an arc from a welding torch provided at the tip of the support cylinder;
A pipe end welding method comprising: One side plate of a pair of opposing side plates has a plurality of tube holes formed in a predetermined arrangement, and the other side plate has a plurality of plug holes formed in the same arrangement as the tube holes corresponding to the tube holes. A pair of box-type headers, and both ends of a number of heat transfer tubes connecting the pair of box-type headers are inserted into the tube holes of each box-type header. An exchanger,
An air-cooled heat exchanger, wherein both ends of each heat transfer tube are automatically welded at the inner surface position of each header, and each heat transfer tube is supported and fixed to each header.   The air-cooled heat exchanger according to claim 2, wherein a ratio between the diameter of the tube hole and the diameter of the plug hole is in a range of 1.00: 1.01 to 1.00: 1.50. A method for producing an air-cooled heat exchanger comprising a pair of box-shaped headers and a large number of heat transfer tubes connecting between the pair of box-shaped headers,
One side plate of a pair of opposing side plates has a plurality of tube holes formed in a predetermined arrangement, and the other side plate has a plurality of plug holes formed in the same arrangement as the tube holes corresponding to the tube holes. A header production process for producing a box-shaped header,
A process of automatically welding the ends of a large number of heat transfer tubes at the inner surface position of the box-shaped header produced by the header production process;
The manufacturing method of the air-cooling type heat exchanger characterized by including this. The automatic pipe end welding process includes:
Preparing a tube end automatic welder having a support tube having a welding torch at the tip and a detachable guide member extending in parallel with the support tube;
A first step of inserting the heat transfer tube into the tube hole and pushing in until the end of the heat transfer tube reaches the inner surface of the one side plate;
A second step of attaching the guide member to the pipe end automatic welder prior to inserting the support tube of the pipe end automatic welder from the plug hole;
A third step of inserting the support tube of the pipe end automatic welder from a plug hole corresponding to a tube hole of a portion to be welded, and pushing in until the tip of the support tube reaches a position near the near side of the tube hole;
Along with the pushing operation of the support cylinder in the third step, the guide member is inserted from a plug hole other than the plug hole corresponding to the tube hole of the welded portion, and the tip of the guide member corresponds to the plug hole. A fourth step that is pushed into the bore,
A fifth step of performing pipe end welding at an inner surface position of the one side plate by an arc from a welding torch provided at the tip of the support cylinder;
The manufacturing method of the air-cooling type heat exchanger of Claim 4 containing this.

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