JP2552566Y2 - Small diameter pipe inner surface welding head - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-diameter pipe inner surface welding head applied to repair welding of the inner surface of a girth weld joint of a small-diameter pipe.

[0002]

2. Description of the Related Art Conventionally, 8B (JIS G3452-1) is used.
988) or less, that is, there is no technology for repair welding the girth welded joint of a small diameter pipe having an outer diameter of 216.3 mm or less from the inner surface.
The method of replacing a new tube is adopted, and there are problems such as an increase in man-hours and an influence on an inspection process. Therefore, a technique that can repair and weld the inner surface of a pipe without disconnecting the pipe is desired.
However, the insertion port in the piping line has only a narrow valve opening, and not only a straight pipe but also a curved pipe is included in the pipe, so that the insertability and passability are good and automatic welding is ensured by remote control. There is a need to develop a small repair welding head that can be installed in a building.

[0003]

[Problems to be solved by the present invention] The present invention has been proposed in view of such circumstances, and it is possible to reliably perform repair welding from the inner surface of a small-diameter pipe without disconnecting the pipe, thereby reducing the number of repair steps. It is an object of the present invention to provide a small-diameter pipe inner surface welding head capable of greatly reducing the number of inspection steps.

[0004]

SUMMARY OF THE INVENTION For this purpose, the present invention is directed to a head for repairing and welding a girth welding joint from the inner surface by inserting the girth welding joint from the valve opening of a small-diameter pipe. A centering fixed plate provided with a guide brush protruding and a projecting plate capable of projecting at a 180 ° symmetrical position, a turning shaft rotatably supported on the front surface of the centering fixed plate, and the turning shaft A welding torch, a fiberscope, and a positioning detector mounted on a holder mounted on the tip of the tube so as to be movable in the tube axis direction and the radial direction.

[0005]

In the present invention, the welding head inserted into the small-diameter pipe from the valve opening is:
While holding the centering and fixing plate with the guide brush, advance to the welding target position with the monitor of the fiber scope, project the backing plate of the centering and fixing plate, and fix the fixing plate coaxially with the small diameter pipe. Next, the holder is moved in the tube axis direction and the radial direction by the monitor of the fiberscope to set the welding torch to the welding start position.

[0006]

FIG. 1 is a side view, FIG. 2 is a plan view, FIG. 3 is a front view, and FIG. 4 shows a procedure for positioning the welding head of the present invention. It is explanatory drawing shown as (I), (II), (III).

In FIG. 1 to FIG. 3, a centering fixing plate 3 is attached to the tip of a flexible pipe 2 for inserting a main welding head from a valve opening (not shown) into a small-diameter pipe 1. A plurality of guide brushes 4 are protruded from the outer periphery of the extension fixing plate 3, and a pair of overhanging contact plates 5 are arranged at 180 ° symmetrical positions. The centering and fixing plate 3 is connected to a flexible tube 6 for introducing a power for extending the backing plate 5 from the outside. A turning shaft 7 is rotatably supported on the front surface of the centering fixed platen 3.

A left and right shaft 8 extending in the tube axis direction is protrudingly provided at the tip of the turning shaft 7, and a feed screw 9 and a motor 10 for driving the feed screw 9 are attached to the left and right shaft 8. A vertical shaft 11 extending in the radial direction is screwed into the feed screw 9, and a pinion gear 12 and a motor 13 for driving the pinion gear 12 are attached to the vertical shaft 11. Further, a holder 14 with a rack is engaged with the pinion gear 12, and a small welding torch 15 is mounted on the lower end of the holder 14, and at a proper distance and angle from the welding torch 15, an arc monitoring device is provided. A fiber scope 16 and a wire nozzle 17 are held. The guide tubes of the fiber scope 16 and the wire nozzle 17 are guided to the outside through the hollow shaft of the swivel shaft 7, and the torch height from the welding surface is set on the side surface of the welding torch 15 in the tube axis direction. A positioning detector 18 is mounted.

The procedure for positioning such a welding head will be described with reference to FIG. 4. First, in FIG. 1 (I), the welding head inserted into the small-diameter pipe 1 through a valve opening (not shown) is a guide brush. While holding the centering and fixing plate 3 at 4, the monitor of the fiberscope 16 advances to the target welding position, and as shown in FIG. It is fixed coaxially with the small diameter pipe 1. Next, as shown in FIG. 3 (III), the welding torch 15 is set to the welding start position on the left and right axes 8 and the vertical axis 11 by the monitor of the fiberscope 16. At this time, it is difficult to accurately set the position of the height of the welding torch 15 on the monitor.

Thereafter, the arc is started from the welding torch 15, the welding is performed by the turning shaft 7, and the arc length of the welding torch 15 is made to follow the vertical axis 11 while maintaining a constant height by the arc length control. All these operations are performed by remote monitoring.

[0011]

In summary, according to the present invention, there is provided a head for repair welding of a girth welded joint from the inner surface by being inserted from a valve opening of a small-diameter pipe. Projected and 18
A centering fixed plate on which a backing plate capable of projecting at a 0 ° symmetrical position is disposed, a turning shaft rotatably supported on the front surface of the centering fixed plate, and a pipe axis direction and a radius at a tip of the turning shaft. With a welding torch, fiberscope and positioning detector mounted on a holder mounted so that it can be moved in any direction, repair welding from the inner surface of small-diameter pipes can be reliably performed automatically without disconnecting the pipes. The present invention is extremely useful in industry because it provides a small-diameter pipe inner surface welding head capable of greatly reducing the number of repair steps and shortening the inspection process.

[Brief description of the drawings]

FIG. 1 is a side view of one embodiment of a small diameter pipe inner surface welding head of the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a front view of the same.

FIG. 4 shows the procedure for positioning the welding head according to (I), (II), and (III).
FIG.

[Explanation of symbols]

 1 Small Diameter Piping 2 Flexible Pipe 3 Centering and Fixing Board 4 Guide Brush 5 Backing Plate 6 Flexible Tube 7 Rotating Axis 8 Left and Right Axis 9 Feed Screw 10 Motor 11 Vertical Axis 12 Pinion Gear 13 Motor 14 Holder 15 Welding Torch 16 Fiber Scope 17 Wire Nozzle 18 Positioning detector

Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location G02B 23/24 G02B 23/24 C (72) Inventor Osamu Fujimoto 1-1-1 Wadazakicho, Hyogo-ku, Kobe-shi, Kobe-shi No. Mitsubishi Heavy Industries, Ltd. Kobe Shipyard (56) References JP-A-54-107446 (JP, A)

Claims (1)

(57) [Scope of request for utility model registration] 1. A head which is inserted from a valve opening of a small-diameter pipe and repairs and welds a girth weld joint from an inner surface thereof. A centering fixed plate having a slidable backing plate disposed at a symmetric position, a turning shaft rotatably supported on the front surface of the centering fixed plate, and a pipe shaft direction and a radial direction at a tip of the turning shaft. A small-diameter pipe inner surface welding head comprising a welding torch, a fiberscope and a positioning detector mounted on a movably mounted holder.