JPS6241824A - Pipe-in-pipe construction - Google Patents

Abstract

PURPOSE:To automatically perform the centering of both new pipes, by a method wherein the diameters of the end sections of a new pipe are previously made shorter than the inner diameter of the new pipe, the end sections of shortened diameters are inserted into the other end sections of non-shortened diameters, and both end sections are welded together through the internal surface sides of the pipes. CONSTITUTION:The diameter of a new pipe 2 of the end sections of shortened diameters is shortened at a necessary length by a shrinker 10 and a bak-up 12, to correspond with a preset pipe, and after that the new pipe 2 is cut off. Then, the new pipe 4 of shortened diameter is inserted into the preset pipe 2, and the pipes are jointed together by fillet weld through the internal surface sides of the pipes. A space between the preset pipe 2 and the new pipe 4 is filled up with mortar 6, and the correction of the preset pie is completed. By this method, the joint structure is provided with excellent characteristic; the work can be executed in very good order, and the joint section can be easily processed.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a method for inserting a new pipe into an existing pipe and placing the existing pipe in a furnace.

``Prior art'' One of the methods for introducing an existing pipe with a large diameter of 1-1 into a furnace is the 77" r method. This 1' method, as shown in Figure 6, Insert this existing pipe into pipe (2),
→ Low noise tr Insert multiple new pipes (4) and butt weld them from the inner surface of the pipe (7) Join these new pipes (4) between the existing pipe (2) and the new pipe (4). It is common to fill the existing pipe with mortar (6).
2) Are you performing rehabilitation work inside the building? Are you having trouble aligning the joints? There is Jffi-C, and there is also a drawback that welding workability and workability are poor. In particular, in terms of quality assurance of butt welds, centering of new pipe (4) to be welded, [1]
Differences, adjustments to grooves, etc. are important, and the work of towara is a bottleneck in improving the efficiency of existing pipe rehabilitation. For this reason, it has been desired to develop a method that is easy and efficient for aligning the joints of the new pipe (4) and for checking the welds, both economically and technologically.

Now, in order to improve the efficiency of the pipe welding method, the seventh
Bell & Spigot 1- as shown in Figure (A) or (I3)
& Fillet welding method is effective. If this is the case, these two
The advantage of this method is that the centering work is easy and the piping work and welding work can be done independently. If these 7-way methods are applied to the rehabilitation of the existing pipe (2) while considering welding from the inner surface of the pipe, the method shown in Figure 7 (A) is the 8th method.
It becomes as shown in Figure (A), and the -I chisel in Figure 7 CB) becomes I' as shown in Figure 8 (13).

[Problems that the invention seeks to solve] However, the two methods shown in FIG. On the other hand, the method shown in Fig. 8 (R) is highly practical, but it requires welding the collar (8) to one end of the new pipe (4) in advance. There is a problem in that it is not acceptable to keep the pipes in place and welding costs are incurred.Also, when rehabilitating existing pipes (2), the length of the straight pipe section is not constant, and new pipes (4) are required depending on the situation. ) must be adjusted, so installing the collar (8) in advance at the factory is not recommended.
There is a problem in that treatment such as cutting the tube is required.

[Means to solve the problem]

This invention was made to solve such problems (7. Inserting M new pipes into the existing pipes and welding the new pipes together (7) Connecting the existing pipes and the new pipes. In the pi-j-in-pipe method in which a filler is filled between the pipes, the end of the new pipe is roughened and reduced in diameter to below the inner diameter of the new pipe, and the contracted end is It is characterized by inserting the tube into the end with no diameter, and welding and joining both ends from the inner surface of the tube.

1 Effect] When one end of a new pipe is inserted into the end of the other new pipe whose diameter is not reduced, both new pipes are automatically centered.

〔Example〕

FIGS. 1 to 3 are explanatory diagrams showing one embodiment of the present invention, and (2) to (6) are the same as those of the prior art described above. However, as shown in Fig. 3, the new pipe (2) with its end reduced in diameter must be placed at the required length position -C to correspond to the existing pipe.
After reducing the diameter using a shrinker (10) and a backup (12), cut the reduced diameter portion into an L shape as shown in FIG. 4. As shown in Figure 1, this new pipe (4) with a reduced diameter is inserted into the existing pipe (2) and connected to the new pipe (2) by fillet welding from the inner surface of the pipe. Mortar (6) is filled between the pipe (4) and the rehabilitation of the existing pipe is completed.

〔Effect of the invention〕

This invention was constructed as described by my son, so the joint structure depicts the features of the Berrus spigot and is suitable for use.
It has very good properties and the joint part is easy to process, so it has the advantage of being sufficiently practical in terms of cost.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing one embodiment of the invention of B, Fig. 2 is an enlarged view of the main part of Fig. 1, Fig. 3 is an explanatory diagram showing a state in which the diameter of the new pipe is reduced, and Fig. 4 is an explanatory diagram showing the state in which the diameter of the new pipe is reduced. Figure 3 is an explanatory diagram showing the state of cutting a pipe whose diameter has been reduced, Figure 5 is an enlarged view of the main part of Figure 4, Figure 6 is an explanatory diagram showing the conventional via-in-pipe method, and Figure 7. (A) and (B) are both explanatory diagrams showing the Bell & Spicott method, and Figures 8 (A) and (B) are explanatory diagrams showing an example of application of the Bell & Spicott method to existing pipe rehabilitation. In the figures, (2) is the existing pipe, (4) is the new pipe, and (6) is the mortar. In each figure, the same reference numerals indicate the same or corresponding parts. Agent: Patent Attorney Sato New Year Figure 7 (A) ? Gorney Figure 8 (A) Figure 7 (B) Figure 8 (B)

Claims (1)

[Claims] In the pipe-in-pipe construction method, which involves inserting a plurality of new pipes into an existing pipe, welding the new pipes together, and filling a filler between the existing pipe and the outer new pipe, the new pipe The diameter of the end of the pipe is reduced in advance to below the inner diameter of the new pipe, the reduced diameter end is inserted into the other end that is not reduced in diameter, and both ends are welded and joined from the inner surface of the pipe. The characteristic pipe-in-pipe construction method.