JPH0534556B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a double pipe structure consisting of a process pipe through which a fluid flows and a hollow cylindrical outer pipe surrounding the process pipe. This article relates to a double pipe structure that allows for easy construction, inspection, etc.

[Technical background of the invention and its problems]

In nuclear power plants, etc., the outer periphery of the process pipe through which fluid containing radioactive materials flows is completely enclosed using an outer pipe with a larger diameter than the process pipe.
A double piping structure is adopted to prevent leaks and outflow accidents due to process pipe rupture.

When installing process pipes using a double piping structure, the long and thin process pipes must be placed and fixed inside a hollow cylindrical outer pipe on site, and the process pipes must be welded together to ensure continuous continuity. Must be connected.

Traditionally, to make this kind of work easier,
All outer tubes have a structure in which they are split in half vertically, and the lower half of the outer tube is first fixed in place, then the process tube is carried in from above and fixed in place within the half tube, and the connecting parts are welded. Finally, the upper half-tube of the outer tube is suspended and brought into contact with the lower half-tube, and the abutting portions are joined by continuous welding in the axial direction.

However, in such a conventional method, there are a large number of parts to be assembled and many parts to be welded, and a large amount of time and labor is required for on-site piping assembly work.

[Purpose of the invention]

The present invention has been made in consideration of these points, and an object of the present invention is to provide a double piping structure that allows on-site piping assembly work and accompanying inspection to be easily performed.

[Summary of the invention]

The present invention has a double piping structure consisting of a process pipe through which a fluid flows and a hollow cylindrical outer pipe that encloses the outer periphery of the process pipe, and the outer pipe has both upper and lower sides at a welded joint of the process pipe. The outer pipe has a separable half structure, and a piping support part is provided near this welded joint, and the outer pipe in this support part has a half structure that can be separated only upwardly. The half tube of the outer tube that can only be separated is characterized in that it is integrally formed with the half tube that can be separated upwardly at the welded joint of the process tube.

According to the present invention, it is possible to weld the process pipe and support work on the half-split structure portion of the outer tube, and the portion other than the half-split structure of the outer tube can be installed as it is as a hollow cylindrical tube. , Piping assembly work for a double piping structure can be performed with the minimum amount of work required.

[Embodiments of the invention]

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

FIG. 1 is a perspective view showing an example of a double piping structure according to the present invention, and FIG. 3 is an exploded perspective view thereof. In the figure, reference numeral 11 denotes a process pipe through which fluid flows, and its end is welded to the end of another process pipe 11 to form a predetermined pipe connection. This process tube 11
is inserted into a hollow cylindrical outer tube 12 having a larger diameter than the process tube 11, and is fixed to a support member 13 fixed within the outer tube 12 using a U-shaped bolt 14. FIG. 2 is a sectional view showing a state in which the process tube 11 is attached and fixed to the support member 13 in the outer tube 12 using a U-shaped bolt 14. The support member 13 is fixed to the lower part of the outer tube 12, for example using an L-shaped channel. The fixation of this support member 13 is as follows:
It is desirable to carry out this process, for example at a factory, before transporting the outer tube to the site.

The outer tube 12 is a welded joint 11a of the process tube 11.
The structure is half-split only at the portion where the support member 13 is fixed. This outer tube 12
The half-split structure is designed so that the upper and lower outer tubes can be separated in order to perform welding work and welding inspection of the process tube 11 at the welded joint 11a, and only the upper part can be separated from the upper and lower outer tubes at the part where the support member 13 is fixed. considered to be separable. In addition, welded joint 1
1a and the fixing point of the support member 13 are provided in a relatively close position, and the outer tube half pipe 12a, which is disposed at the fixing point of the support member 13 and can be separated only upward, is attached to the welded joint 11a. It is formed integrally with the upper half-tube. As a result, the upper half tube 12a becomes longer than the half tube 12b that is separated downward. The portion of the outer tube 12 other than the half-split structure is a completely hollow cylindrical tube.

Next, the operation of this embodiment having such a configuration will be explained.

At the factory (including a special factory on site), it is processed into a predetermined half-split structure, and the support member 1
After the outer tube 12 to which the tube 3 is fixed is transported to the site, the hollow cylindrical tube portion is gripped by the support member 15 and fixed. Next, the process tube 11 is inserted into the outer tube 12 using the half-split structure. In this case, since the upper half tube 12a is relatively long, the open portion of the outer tube 12 becomes larger by that length, and even a long and narrow process tube 11 can be easily inserted into the outer tube 12. After the process tube 11 inserted into the outer tube 12 is temporarily fixed,
The end portion is joined to the end portion of another process tube 11 by welding. This welding work consists of 12 halved pipes in the vertical direction.
Since a and 12b are separated, this can be easily carried out, and the inspection after welding can also be easily carried out. When the welding of the process pipe 11 is completed, the process pipe 11 is attached using the U-shaped bolt 14.
is fixed to the support member 13. Subsequently, the upper half tube 12a and the lower half tube 12b are combined and their abutting portions are welded. In this case, the upper half tube 12a is first fixed to the half portion of the outer tube 12 which is fixedly arranged, and then the lower half tube 12b is welded to the upper half tube 12a. For example, the half tubes 12a, 12b can be easily positioned and joined accurately.

As for the elbow piping section 17, it is desirable to complete the assembly work at the factory in advance, since the work at the site is troublesome.

〔Effect of the invention〕

As explained above, according to the present invention, the upper and lower outer tubes can be separated at the welded portion of the process tube, the piping support portion is provided near the welded portion, and the outer tube at this support portion can be separated only from the upper side. Since this separable half-tube is formed integrally with the separable half-tube above the welded portion of the process tube, welding work and inspection of the process tube can be performed easily and quickly. Furthermore, since the upper half-tube is longer than the support, the open portion of the outer tube becomes larger, and even a long and narrow process tube can be easily inserted into the outer tube. Furthermore, since the amount of half tubes is minimized, the amount of half tubes to be transported is small, making on-site work easier. Furthermore, piping assembly work can be performed by manufacturing a unit structure in a factory in which a process pipe is inserted and fixed in advance into a hollow cylindrical outer pipe with a half-split structure at the end, and connecting this on-site. , it can also significantly simplify on-site work.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an example of a double piping structure according to the present invention, Fig. 2 is a sectional view taken along the line shown in Fig. 1, and Fig.
This figure is an exploded perspective view of the embodiment shown in FIG. 1. 11... Process pipe, 11a... Welded joint,
12...Outer tube, 12a, 12b...Half tube, 13
...Support member, 14...U-shaped bolt.

Claims (1)

[Claims] 1. In a double piping structure consisting of a process pipe through which fluid flows and a hollow cylindrical outer pipe that encloses the outer periphery of this process pipe, the outer pipe is divided into halves that can be separated from each other at the welded joint of the process pipe. A pipe support section is provided near this welded joint, and the outer pipe at this support section has a halved structure that can be separated only upwardly. A double piping structure characterized in that the half pipe of the pipe is integrally formed with a half pipe that can be separated upwardly at the welded joint of the process pipe.