JPS628263B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an underwater welding device using a local dry method for welding an annular welding part of a pipe material, and in particular, it is designed to prevent water from entering and to monitor the welding condition while performing the work. This is what I did.

Currently, there are two types of underwater welding methods: the wet method, in which shielded arc welding or gas-shielded arc welding is performed underwater, and the other is the wet method, in which the entire workpiece to be welded is surrounded by a special container, in which the worker enters the container and is fully exposed to the atmosphere. Two methods are known: a dry method in which welding is carried out in the same atmosphere as the welding area, and a local dry method in which welding is carried out by locally draining only the welded area. Although the wet method is versatile, the quality of the welded part is inferior to other methods due to the rapid cooling caused by the surrounding water, making it difficult to apply to parts that require high weld strength. In addition, although the dry method allows the quality of welded parts to be equivalent to that in the air, the disadvantage is that the equipment itself is large-scale and lacks versatility, and the cost is high, which limits the range of application. There is. For this reason, a local dry method, which has features intermediate between the wet method and the dry method, has been developed and is being widely adopted in various fields.

As shown in Figure 1, which shows the typical working principle of the local dry method, a flexible member 1 such as a sponge is attached at the lower end.
A welding torch 3 is attached to the center of a box-shaped transparent main body 2 to which a welding torch 3 is attached, and while pressing the flexible member 1 together with the main body 2 against the workpiece 4 to be welded, Gas is forced into the chamber from the welding torch 3 or a gas supply pipe (not shown), and after the water in the welding chamber 5 is discharged to the outside, the welding operation is started. However, in the above-mentioned method called the simple box method, as the welding work progresses, the gas in the welding work chamber 5, which becomes high pressure, leaks into the water, becomes fine bubbles 6, and floats in large quantities. This has the disadvantage that it is difficult to monitor the welded area from underwater. This also applies to the method shown in FIG. 3, which is called the water jet method. This method uses a special shaped double nozzle 7,
8 is used to spray water at high speed from the outer nozzle 7 to form a water curtain, and at the same time, the inner nozzle 8
Gas is forced into the welding work chamber 5' from the welding chamber 5', water is removed from the welding chamber 5', and the workpiece 4' is welded with the welding torch 3'. This is because when colliding with 4', gas is drawn in and bubbles 6' are generated.

For this reason, a simple box system has been proposed in which a gas vent pipe 9 communicating with the welding work chamber 5 is connected to the main body 2 as shown in Fig. 2, which allows for good monitoring of the welding work status. However, when the main body 2 is moved together with the welding torch 3 as the welding work progresses,
The amount of deflection of the flexible member 1 changes and the welding work chamber 5
Because pressure fluctuations occur inside the building, there was a risk that water could enter here. In particular, when butt welding cylindrical members to be welded, it is almost impossible to completely drain the inside of the welding work chamber 5, partly because the welded portion is annular.

The present invention solves the drawbacks of the above-mentioned conventional local dry method-based equipment for welding annular pipe materials, and provides an underwater welding equipment that can prevent water from entering and at the same time monitor the welding work status. The purpose is to provide.

The configuration of the underwater welding apparatus of the present invention that achieves this object is to double surround the annular welding portion of a pair of members to be welded, each of which is cylindrical and abutted against each other, and the surface of the member to be welded is An annular external water-stopping wall and an annular internal water-stopping wall located inside the annular water-stopping wall that are in close contact with the welding portion, respectively, and an annular transparent water-stopping wall that faces the welding part and is provided almost parallel to the welding part and equipped with a welding torch. The pipe is attached to both ends of a supporting plate so as to be relatively rotatable, and the pipe is connected to the water from an annular welding chamber surrounded by the internal water-stopping wall and the support plate and filled with gas through the external water-stopping wall into the water. A suction chamber is formed between the external water-stopping wall and the internal water-stopping wall to prevent gas leakage and water from entering the welding work chamber from underwater, and the suction chamber is further provided with a This system is characterized by communicating an exhaust gas pipe and a drain pipe that discharge gas and water, respectively.

Hereinafter, one embodiment of the underwater welding apparatus according to the present invention will be described in detail with reference to FIGS. 4 to 7. As shown in FIG. 4, which shows the external appearance of the apparatus of this embodiment, and FIG. 5, which shows the cross-sectional structure of its main parts, a transparent annular slide plate 11 made of acrylic resin or the like has sealing members 12 at both ends thereof.
It is connected to a pair of annular support plates 13 via the cylindrical support plate 13, and is rotatable around the cylindrical member 14 to be welded relative to the support plates 13. Note that if the support plate 13 is also made of a transparent member such as glass, monitoring workability will be improved. Slide plate 11
A torch attachment hole 16 through which the welding torch 15 passes is bored in the center of the welding torch 16. The welding torch 16 inserted into the torch attachment hole 16 is attached to a sealing member 17 such as a bellows so that the welding torch 16 can be tilted to some extent. It is suspended from the slide plate 11 via. Further, around the support plate 13, the support plate 13 and the slide plate 11 are attached to a member to be welded 14.
In order to position the tip concentrically with the workpiece 1,
A plurality of positioning bolts 18 that can come into contact with the surface of 4 are screwed into the support plate 13 at equal intervals,
As a result, the support plate 13 is fixed to the member to be welded 14.

On the other hand, a holding frame 21 that accommodates an internal water-stopping wall 19 and an external water-stopping wall 20, each of which has a double structure made of sponge or the like, whose inner peripheral surfaces are in contact with the surface of the welded member 14, is connected to the pair of supporting plates. Therefore, the pair of internal water-stop walls 19, the slide plate 11, and the support plate 13 form a sealed space surrounding the welding part 22, which becomes a welding work chamber 23. As the welding work progresses, fumes and the like may adhere to the inner surface of the slide plate 11, making it difficult to monitor the interior of the welding work chamber 23.
Therefore, in this embodiment, a brush holder 25 in which cleaning brushes 24 that can come into sliding contact with the inner surface of the slide plate 11 are flocked is attached to the support plate 13, and the rotation of the slide plate 11 automatically cleans the inner surface of the brush holder 25. It is designed so that it can be wiped with a cleaning brush 24. or,
Between the internal water-stop wall 19 and the external water-stop wall 20, gas leaking from the welding work chamber 23 through the internal water-stop wall 19 to the underwater (outside) side is temporarily stored, and an external water-stop wall is provided. A suction chamber 26 is formed in which water that enters the welding work chamber 23 through the welding chamber 20 is temporarily stored. At the upper end of this suction chamber 26 is an exhaust gas pipe 27 that sucks the gas filled here to the outside.
As shown in FIG. 7, which shows a cross-sectional structure similar to that shown in FIG.
8 are connected. Furthermore, a gas supply pipe 29 for water shutoff is connected to the support plate 13, the internal water shutoff wall 19, and the external water shutoff wall 20, and gas is fed under pressure thereto. The pressure inside the work chamber 23 is the highest, followed by the internal water stop wall 1.
9, the atmospheric pressure is adjusted in the order of the external water stop wall 20 and the suction chamber 26. In this case, if the pressure balance between the water pressure in the water and the external water stop wall 20 is set so that the water pressure is slightly higher, there is less risk of air bubbles blowing out into the water, and this will not interfere with monitoring work. .

It should be noted that the apparatus of this embodiment has a structure in which the whole is divided into two pieces, which are integrated into a cylindrical shape by means of a plurality of pins 30, so that the attachment work to the member to be welded 14 can be performed quickly and easily.

When carrying out actual welding work using the apparatus of this embodiment, first the welded portion 22 of the workpiece 14 is
The semi-cylindrical two-split device is integrated via pins 30 so as to surround it, and the positioning bolt 18 is operated to adjust the entire device to be the same (coaxial) as the member to be welded 14. Thereby, even if the slide plate 11 is rotated, the distance between the tip of the welding torch 16 and the welded portion 22 of the member to be welded 14 can be kept constant.

Next, pressurized gas is supplied from the gas supply pipe 29 to the inside of the welding work chamber 23 and to the internal water-stop wall 19 and the external water-stop wall 20, while the exhaust gas pipe 27 and the drain pipe 28 are used to supply pressurized gas to the suction chamber 26. The gas and water flowing into the welding work chamber 23 are sucked out and the inside of the welding work chamber 23 is drained. The gas leaking from the welding work chamber 23 filled with gas flows into the suction chamber 26.
Since there is no risk of air being sucked into the exhaust pipe 27 and leaking from the suction chamber 26 directly into the water through the external water stop wall 20, air bubbles are not generated and the operator can weld through the slide plate 11 and support plate 13. The inside of the room 23 can be clearly monitored. Furthermore, water flowing from the outside toward the welding work chamber 23 accumulates in the lower part of the suction chamber 26 and is discharged from there to the outside through the drain pipe 28, as shown in FIG. There is almost no possibility that water will flow into the chamber 23.

Thereafter, while maintaining this state, a welding arc is generated, and the welding work is proceeded while rotating the slide plate 11. This rotation operation of the slide plate 11 may be performed manually, but as shown in FIG. 6, which shows a part of the cross-sectional structure similar to FIG. gear 31
A gear 3 meshing with this gear 31
2 may be installed on the support plate 13 to automatically perform the operation. The welding speed (rotation speed of the slide plate 11) and welding torch 16 are adjusted in response to changes in the groove shape and position of the welding part 22.
Proceed with the welding work while adjusting the target position. Incidentally, fogging on the inner surface of the slide plate 11 due to fumes and the like is wiped away by the cleaning brush 24, making it possible to maintain good visibility.

As described above, according to the underwater welding apparatus of the present invention, the welding work chamber surrounding the annular welding portion of the pair of members to be welded is surrounded by double water-stop walls, and a suction chamber is formed between these walls. Gas leaking from the welding work chamber and water entering from the outside are discharged to the outside from this suction chamber, so air bubbles will not leak into the melt water and water will not enter the welding work room. Highly reliable welds can be formed while monitoring the welding state.

[Brief explanation of the drawing]

Figures 1 to 3 are work principle diagrams showing the underwater welding work status by the conventional local dry method, respectively.
The figure is a front view of one embodiment of an underwater welding device according to the present invention, FIG. 5 is an upper part of a cross-sectional view showing its structure, and FIG. 6 is a broken view showing a slide plate driving means in another embodiment of the present invention. 7 shows the lower part of the cross-sectional view similar to FIG. water wall,
20 is an external water stop wall, 21 is a holding frame, 22 is a welding section, 23 is a welding work chamber, 26 is a suction chamber, 27 is an exhaust gas pipe, 28 is a drain pipe, and 29 is a gas feed pipe.

Claims (1)

[Claims] 1. An annular external water stop wall doubly surrounding the annular welded portion of a pair of welded members that are cylindrical and abut against each other and that are in close contact with the surfaces of the welded members, and a water stop wall on the inside thereof. an annular internal water stop wall, which is provided so as to be relatively rotatable at both ends of an annular transparent support plate, which is provided opposite to and substantially parallel to the welding portion, and to which a welding torch is attached; Preventing the leakage of the gas from the annular welding chamber surrounded by the internal water-stop wall and the support plate and filled with gas into the water via the external water-stop wall, and preventing leakage of the gas from the water into the welding work chamber. A suction chamber that prevents water from entering is formed between the external water-stopping wall and the internal water-stopping wall, and an exhaust gas pipe and a drain pipe are connected to the suction chamber to discharge gas and water, respectively, from the suction chamber. An underwater welding device characterized by: