JPS5926840B2 - Insulated piping structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-insulating structure for piping for transporting a high-pressure heat medium at high or extremely low temperatures.

When transporting a heat medium through a pipe as described above, if the structure is such that the heat medium comes into direct contact with the pressure-resistant tube, the temperature of the pressure-resistant tube becomes high or extremely low, and there is no mechanical system to maintain the specified high pressure. It may not be possible to maintain strength.

For this purpose, a liner tube is inserted inside the pressure tube, a heat insulating material is filled between the pressure tube and the liner, and the heat medium is passed through the liner tube, allowing heat to be transferred between the heat medium and the pressure tube. Usually, a structure is adopted that can block the pressure as much as possible and maintain the temperature of the pressure tube at an appropriate value.

Conventionally, a structural example as shown in FIG. 1 has been devised.

In Fig. 1, 01 is a pressure-resistant outer tube, 02 is a liner tube, and 03 is a pressure-resistant outer tube.
04 is a heat medium, and 05 is a radial partition plate.

The gap C is for absorbing the difference in thermal expansion caused by the temperature difference between the pressure-resistant outer tube 01 and the liner tube 02, and W indicates a welded portion.

In the one shown in FIG. 1, the radial partition plate 05 holds the liner pipe 02 against the pressure-resistant outer pipe 01, and
It is installed in order to partition the liner pipe 02 in the axial direction and prevent the convection of the heat medium as shown in FIG. 2, which is expected to occur at each joint of the liner pipe 02.

If such local convection of the heat medium 04 occurs, there will be a problem that the temperature of the pressure-resistant outer tube 01 will rise or fall significantly.

The procedure for actually manufacturing the conventional structure as described above is normally as follows.

That is, the next pressure-resistant outer pipe 01 and liner pipe 02 are joined to the end face of the transport pipe 010 assembled in the previous step, and the pressure-resistant outer pipe 01
Perform butt welding all around.

A suitable heat insulating material 03 is filled between the end face of the pressure-resistant outer pipe 01 and the liner pipe 02, and then a disc-shaped radial partition plate 05 is fitted to the end face to form a joint between the pressure-resistant outer pipe 01 and the liner pipe 02. Weld it circumferentially.

Next, repeat the same operation.

This conventional structure has the following problems.

(a) During production, filling with the heat insulating material 03 must be carried out each time at the construction site of the transport pipe, which inevitably impairs work efficiency and increases construction time.

Furthermore, the working environment is poor, and quality control, such as the degree of filling and cleanliness of the insulation material, cannot be properly controlled.

(Middle) During operation, the heat insulating material 03 tends to scatter from the gap between the joints of the liner pipes 02.

(・→ If the welded part of the radial partition plate 05 to the pressure-resistant outer pipe 01 or the liner pipe 02 breaks during operation, a convection of the heat medium as shown by the arrow in Fig. 3 will occur, and the pressure-resistant outer pipe 01 and the liner pipe 02 A local temperature rise or fall occurs in the pipe 01.

The present invention has been made for the purpose of eliminating the above-mentioned problems of the conventional structure and further improving the weldability of the pressure-resistant outer tube.

The present invention will be explained below based on the illustrated embodiments.

In FIGS. 4 and 5, a pressure-resistant outer tube 10 of a predetermined length is shown.
Welding grooves 1a and 1b are cut at both ends.

An inner tube 2 is arranged almost coaxially inside the pressure-resistant outer tube 1, and both ends of the inner tube 2 have extensions 2a and 2b so as to be slidably connected to the ends of other adjacent inner tubes 2. has.

The shape and dimensions of the inner tube 2 are set so as to create a gap C when adjacent pressure-resistant outer tubes 1 are welded together at room temperature.

Corresponding ends of the pressure-resistant outer tube 1 and the inner tube 2 are connected by a partition member, that is, a disk-shaped bellows member 5, which is shown in a simplified manner.

That is, the inner and outer edges of the bellows member 5 are hermetically welded to the outer surface of the inner tube 2 and the inner surface of the pressure-resistant outer tube 1, respectively.

The inner edge of the bellows member 6, which has approximately the same shape as the bellows member 5, is hermetically welded to the outer surface of the inner tube 2 near the proximal end of the extension portion 2b, and the outer edge of the bellows member 6 is attached to the groove 1b of the pressure-resistant outer tube 1. Adjacent cylindrical flanges 7 are formed, which flanges 7 are used as backing metals when the pressure-resistant outer tubes 1 are butt welded together.

A heat insulating material 3 is filled in an annular space surrounded by the pressure-resistant outer tube 1, the inner tube 2, and the bellows members 5 and 6.

Pressure-resistant outer pipe 1, inner pipe 2, bellows members 5, 6, and heat insulating material 3
The unit piping 10 constructed as shown in FIG.

According to this embodiment having the above-described configuration, the high-temperature heat medium flows inside the inner tube 2, and the inner tube 2 directly touches the heat medium and becomes high temperature, whereas the pressure-resistant outer tube 1 is heat-insulated. The temperature is maintained below a predetermined temperature due to the adiabatic effect of feature 3.

The difference in thermal expansion caused by the temperature difference between the pressure-resistant outer tube 1 and the inner tube 2 described above is absorbed by the gap C and the deformation of the bellows member 5°6.

According to this embodiment having the above-described configuration and operation, the unit piping 10 can be manufactured in a factory with well-equipped equipment and environment, so the insulation material 3 can be filled cleanly and densely, and when all piping is completed, The pressure-resistant outer tube 1, the inner tube 2, and the bellows members 5 and 6 are hermetically sealed so that the heat insulating material 3 does not scatter during operation, and the difference in thermal expansion is absorbed by the gap C and the bellows members 5 and 6, resulting in welding. The temperature of the pressure-resistant outer tube 1 can be appropriately maintained without causing a local convection phenomenon of the heat medium.

Furthermore, since the bellows member 6 acts as a backing metal for welding the pressure-resistant outer tube 1, the welding can be performed appropriately.

Furthermore, in the above embodiments, the heat medium is used for a high-temperature one, but those skilled in the art will easily understand that it can also be used for a very low-temperature heat medium without changing the structure.

Although the embodiments have been described above, the present invention also includes a pressure-resistant outer tube,
An inner tube arranged substantially concentrically within the outer tube and having approximately the same length as the outer tube, and at least two tubes sandwiched between the inner tube and the outer tube at both ends to form a sealed space between the inner tube and the outer tube. The present invention relates to a heat insulating piping structure in which unit pipes made of a partition member and a heat insulating material filled in the sealed space are successively joined, and a space for absorbing thermal expansion difference is formed between end faces of adjacent inner pipes. According to the method, a unit pipe consisting of a pressure-resistant outer pipe, an inner pipe, a partition member, and a heat insulating material was manufactured in a suitable environment, and the cleanliness and filling degree of the heat insulating material could be appropriately controlled, and the heat insulating material was sealed by the partition member. Therefore, it is possible to prevent the scattering of the heat insulating material and the occurrence of local convection of the heat medium, thereby preventing a decrease in mechanical strength due to an excessive rise or fall in the temperature of the pressure-resistant outer tube.

[Brief explanation of drawings]

Figures 1, 2, and 3 are explanatory diagrams of conventional structures;
FIG. 5 is a sectional view showing an embodiment of the present invention. 1...Pressure-resistant outer tube, 2...Inner tube, total...
...Insulating material, 5.6...Bellows member, 10
・・・・・・Unit piping.

Claims (1)

[Claims] 1. A pressure-resistant outer tube, an inner tube disposed almost concentrically within the outer tube and having approximately the same length as the outer tube, and an inner tube sandwiched between both ends of the inner tube and the outer tube and welded to the inner and outer tubes to form a sealed space. The ends of the outer tube of a unit pipe made of two partition members and a heat insulating material filled in the sealed space are successively welded together, and thermal expansion between the end surfaces of the adjacent inner tubes is achieved. A heat insulating piping structure, characterized in that a space for absorbing a difference is formed, a flange formed on one outer edge of the partition member is located close to the inner surface of the end of the outer tube, and serves as a backing for the welding.