JPH0421675Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a welding device for welding tubes and tube sheets for manufacturing multi-tube cans such as heat exchangers. The present invention relates to a welding device equipped with a center rod that fits into the pipe for the purpose of welding.

[Conventional technology]

Conventionally, as this type of welding device, one having the configuration shown in FIG. 2 is known. To explain the welding device having this configuration, a center rod 14 rotatably fitted into the tube 13 is disposed at the front end 12 of the main shaft 11, the tip thereof serves as the centering portion 14, and the rear end 15 includes a motor etc. The welding torch 17 is provided with a drive mechanism 16 and a welding torch 17 which is rotated together with the centering portion of the center rod 14 by the drive mechanism 16 via the rotating main shaft 11.

The centering portion 24 of the center rod 14 is rod-shaped and has a plurality of kerfs formed in the axial direction, and the diameter thereof is variable, and other parts of the center rod 14 are provided with cooling water holes. The structure is such that cooling water flows in and out of this hole. In addition, for other structures (not shown), a cooling mechanism using the above-mentioned cooling water is provided on the rear side of the welding torch.
(See Publication No. 14707).

These welding devices are equipped with center rod 1.
4, the centering part 24 of the tube 13 is inserted into the tube plate 20.
The welded portion 2 between the tube plate 20 and the tube end 21
2 and the tip of the non-consumable electrode 23 made of tungsten or the like of the welding torch 17 is positioned to maintain a constant distance, and then the drive mechanism 16 is driven while cooling water is flowing into and out of the cooling water hole 25. By rotating the welding torch 11, the welding torch 17 disposed on the main shaft 11 can be rotated in forward and reverse directions with each rotation, and the welding arc can be generated with the electrode 23 to weld the welding part 22. ing.

Therefore, this welding device has excellent effects in that the core runout of the welding torch is small and the imbalance in heat capacity between the tube and the tube sheet can be improved.

[Problem that the invention attempts to solve]

However, since the above-mentioned welding apparatus has the above-described configuration, it has been found that it has the following problems. That is, since the structure is such that the imbalance in heat capacity between the tube and the tube sheet is reduced by flowing cooling water, the structure becomes complicated and large.

The centering part of the center rod holds the tube in one place, and since it cannot be adjusted, the welding torch core remains out of alignment.

Since the insulation part and the welding torch are fixedly integrated, it is difficult to replace them.

Therefore, in order to address the above-mentioned problems, a configuration was developed in which a plurality of leaf springs were used in the centering part of the center rod to prevent the welding torch from wobbling.
52-55922), and a configuration in which the centering part is detachable to accommodate different pipe diameters (see
53-43608) has been proposed.

However, with this configuration, sufficient centering cannot be achieved and the cooling configuration is complicated. Furthermore, in the case of conventional welding torches, there are cases where the welding start point shifts.

In view of the above points, it is an object of the present invention to provide a welding device for welding pipes and tube sheets that is equipped with a center rod that is easy to use and that solves the problems of the conventional devices described above. .

[Means for solving problems]

The welding device for welding a tube and a tube sheet of the present invention to achieve the above-mentioned object rotates along a welded part formed by the tube sheet and the tube end of the tube inserted into the tube sheet. a welding torch that performs welding while welding, and a center rod that is inserted into the pipe in order to maintain a constant distance between the tip of a non-consumable electrode of the welding torch and the welding part and position the welding part, the tip of the center rod is the centering part, the middle part is the heat radiating part, and the rear end part is the insulating part, and the centering part, the heat radiating part, and the insulating part are each independently detachable. A welding device for welding a tube and a tube plate, in which a drive mechanism for rotating a welding torch is provided at the rear end portion so as to be detachably attached to the insulating portion, and the centering portion is located at the center of each of a plurality of leaf springs. a spindle-shaped spring formed by bending a portion thereof so as to protrude outward;
It has an adjusting device such as a spring-like spring that adjusts the elasticity of the spindle-shaped spring, and an enlarged diameter part disposed at the rear end, and the protruding surface of the spindle-shaped spring and the enlarged diameter part are used to control the inside of the pipe. The drive mechanism is configured to hold the welding torch, and the drive mechanism includes a forward rotation drive means for rotating the welding torch in the forward direction from the welding start point to a position slightly more than one rotation, and a return means for returning the welding torch to the welding start point. and a reverse rotation driving means for rotating the welding torch in the opposite direction from the welding start point to a position slightly more than one rotation, and further, the heat radiating part is formed of a heat radiating member having an uneven shape in the circumferential direction. Consists of composition.

[Effect]

Next, the operation of the present invention will be explained based on the above configuration. Here, a configuration using a ring of filler material as the welding rod (filler material) will be described.

First, after placing the above ring around the tube, when the centering part of the center rod located at the tip of the main shaft is inserted into the tube inserted into the tube plate, the outer peripheral surface of the leaf spring and the enlarged diameter part The tube is held at two points, and the welding position is determined so that the distance between the weld between the tube plate and the tube end and the tip of the non-consumable electrode made of tungsten or the like of the welding torch is kept constant.

Next, a drive mechanism such as an electric motor is driven to rotate the welding torch along the welding section, and during the rotation, a welding arc is generated by the electrode to weld the welding section, and here the tube and tube sheet are joined together. The heat dissipation section formed by the uneven heat dissipation member reduces the imbalance in heat capacity of the Since it is detachable, it can be easily replaced and can be used for various welding types.

〔Example〕

Embodiments of the present invention will be specifically described below with reference to the drawings.

Here, FIG. 1 is a partially cutaway side view showing an embodiment of the present invention, and FIG. 2 is a partially cutaway side view of a conventional device.

The apparatus for welding a tube and a tube sheet shown in this embodiment is roughly divided into a drive mechanism 31, a welding torch 33, and a center rod 32.

The center rod 33 has a centering part 34 at its tip, a heat radiating part 35 at its middle part, and an insulating part 36 at its rear end. It has a structure that allows it to be installed and removed.

Here, the centering portion 3 of the center rod 32 is
4 is formed by a plurality of leaf springs 37, an adjusting device 38 such as a spring-like spring that adjusts the elasticity of the leaf springs 37, and an enlarged diameter portion 39 disposed at the rear end, and the enlarged diameter portion 40 is connected to the protruding surface 40 of the leaf spring 37. It is configured to hold the inside of the pipe at two locations, including the diameter portion 39. In addition, the leaf spring 37 is provided with a locking tool 42 at its front and rear ends.
Further, an adjustment screw 43 for adjusting the spring force of the spring-like spring 38 is disposed at the rear end of the spring-like spring 38.

The heat radiating portion 35 is formed of a shaft (heat radiating member) having an uneven shape 44 in the circumferential direction, and the insulating portion 36 is formed of a molded product of Bakelite.

Moreover, the centering part 34, the heat radiation part 35, and the insulating part 36 are each formed so that they can be attached and detached by fitting. Further, the rear end portion of the insulating portion 36 is formed so that it can be attached to and removed from a fixed shaft (main shaft) 45.

The drive mechanism 31 is usually formed by an electric motor and is arranged around the intermediate portion of the fixed shaft 45 . The driving force of the drive mechanism 31 is transferred to the fixed shaft 45.
The rotational force of the drive mechanism 31 rotates the rotary body 46, and the welding torch 33 disposed on the rotary body 46 rotates at a constant rate. It is configured as follows.

Here, the welding torch 33 is configured to rotate in forward and reverse directions by detecting the moving position of the welding torch with a detection mechanism 47 disposed between a rotating body 46 and a fixed shaft 45. That is, when the welding torch 33 makes one rotation in one direction from the zero point, the detection mechanism 47 detects the moving position of the welding torch 33, and after stopping the generation of the welding arc, the driving mechanism 31 rotates the welding torch 33 by about 45 degrees further in the moving direction. Then, when the welding torch 33 is returned to the zero point and rotated once in the opposite direction while generating a welding arc by detection by the detection mechanism 47, the position is detected by the detection mechanism 47 and the welding arc is generated. The welding torch 33 is then rotated about 45 degrees in the same direction and returned to the zero point again to perform welding, and in the event of an emergency, it is driven so that an emergency stop and reset can be performed at the same time. Configuring.

Note that the detection mechanism 47 can be easily configured by a conventionally known combination of a limit switch and a timer circuit, for example, and a person skilled in the art can easily construct a specific circuit and device for this sequence circuit by using the above-described operating method. Therefore, the specific configuration will be omitted.

With this configuration, only one detection mechanism 47 is required, so the configuration of the entire welding apparatus can be further simplified.

The welding torch 33 has a commonly used configuration, and uses a non-consumable electrode 48 made of tungsten or the like as its core wire. The tip of the electrode 48 of this welding torch 33 is connected to the tube 41 and the tube plate 4.
It is disposed on the rotary body 46 so as to be able to rotate so as to face the welded portion with 9.

It is preferable that the electrode 48 of this welding torch 33 has a structure in which its protruding length can be automatically maintained at a constant length. Normally, when the tool wears out, an operator performs centering, but this work requires a certain degree of skill.

The structure is such that the electrode 48 can be centered in accordance with changes in the gas pressure of the shielding gas supplied into the welding torch 33.

Next, the operation of the welding apparatus of this embodiment will be explained based on the above configuration. Here, a configuration using a ring of filler material as the welding rod (filler material) will be described.

First, after placing the above ring around the tube 41,
The centering portion 34 of the center rod 32 disposed at the tip of the fixed shaft 45 is inserted into the tube plate 49.
1, the tube 41 is held by the outer circumferential surface 40 of the leaf spring 37 and the enlarged diameter portion 39, and the welded portion 50 between the tube plate 49 and the end of the tube 41 and the welding torch 33 are held together. Welding positioning is performed so that the distance between the tips of non-consumable electrodes 48 such as tungsten is kept constant.

Subsequently, the drive mechanism 31 such as an electric motor is driven to rotate the welding torch 33 along the welding part 50, and during the rotation, a welding arc is generated by the electrode 48 to weld the welding part 50, and here the pipe 41 and tube plate 4
The heat dissipation part 35 reduces the imbalance in heat capacity between the insulation part 36 and the insulation part 36.
It acts to remove it.

Note that in the above embodiments, the rotating body 46 is not limited to the shape of the housing as shown in the drawings, but may have a simple shape, for example, and in this case, normally only the drive mechanism 31 is disposed within the housing. The configuration will be as follows.

Furthermore, the relationship between the drive mechanism 31 and the welding torch 33 is not limited to the above-described configuration, but may be a normal configuration in which the fixed shaft 45 is a rotating shaft to which the driving force is transmitted by the drive mechanism 31. It is clear that the welding torch 33 and the center rod 32 may be disposed on a rotating shaft and rotated in the same manner. [Effects of the invention] As is clear from the above description, in the pipe-to-tube sheet welding device of the present invention, the centering portion is formed by a spindle-shaped spring whose elasticity can be adjusted using an adjustment device such as a spring spring. In addition, since the interior of the tube is fixed at two locations, the protruding surface of the spindle-shaped spring and the enlarged diameter portion, the centering portion and the tube are in close contact with each other, thereby reducing core deflection of the welding torch.

Further, the drive mechanism includes a forward rotation drive means for rotating the welding torch to a position slightly more than one rotation in the forward direction from the welding start point, a return means for returning the welding torch to the welding start point, and a return means for returning the welding torch to the welding start point; Since the welding torch is configured to include a reverse rotation drive means for rotating the welding torch slightly more than one rotation in the opposite direction, a single detection mechanism can detect the position of the welding torch, and the welding torch is passed through the welding start point in advance. After moving to the position, the welding point is returned to the welding start point, so it is possible to eliminate the positional deviation of the welding position.

Furthermore, since a heat dissipation section is formed between the centering section and the insulating section, and the heat dissipation section is made of an uneven heat dissipation member, the heat capacity imbalance between the tube and the tube sheet can be reduced.
It is lightweight and can be easily reduced. Furthermore, a drive mechanism for driving the welding torch is provided at the rear end of the insulating part of the center rod so that the insulating part can be attached and removed, making it easy to replace the insulating part without moving the welding torch. have

Therefore, according to the present invention, it is possible to provide a welding device for welding a tube and a tube sheet, which is lightweight, easy to perform partial repair and handling, and can reduce core runout.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side view showing an embodiment of the present invention, and FIG. 2 is a partially cutaway side view of a conventional device. 31... Drive mechanism, 32... Center rod,
33... Welding torch, 34... Centering part, 35...
...Heat radiation part, 36...Insulation part, 37...Plate spring, 3
8... Spring-like spring (adjuster), 39... Expanded diameter portion, 40... Projecting surface.

Claims (1)

[Scope of utility model registration request] A welding torch that performs welding while rotating along a weld formed by a tube sheet and a tube end of a tube inserted into the tube sheet, and a tip of a non-consumable electrode of the welding torch and the weld portion and a center rod that is inserted into the tube in order to maintain a constant distance from the pipe and position the welding part, the tip of the center rod serves as a centering part, the middle part serves as a heat dissipation part, and the rear end serves as an insulating part. The centering section, the heat dissipation section, and the insulating section are each independently attachable and detachable, and a drive mechanism for rotating a welding torch is attached to and detachably from the insulating section at the rear end of the insulating section of the center rod. The centering part includes a spindle-shaped spring formed by bending the central part of each of a plurality of leaf springs so as to protrude outward, and an elasticity of the spindle-shaped spring. It has an adjusting device such as a spring-like spring for adjusting the amount, and an enlarged diameter part disposed at the rear end, and is configured to hold the inside of the pipe at two places: the protruding surface of the spindle-shaped spring and the enlarged diameter part. Further, the drive mechanism includes a forward rotation drive means for rotating the welding torch in the forward direction from the welding start point to a position slightly more than one rotation, a return means for returning the welding torch to the welding start point, and a return means for returning the welding torch to the welding start point. and a reverse rotation driving means for rotating the welding part slightly more than one rotation in the opposite direction from the welding start point, and further characterized in that the heat radiating part is formed of a heat radiating member having an uneven shape in the circumferential direction. Equipment for welding pipes and tube sheets.