JPH0364031B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a construction method for a double-shell low-temperature tank in which a powder-like cold insulating material is filled between an inner tank side plate and an outer tank side plate. .

[Conventional technology]

In a typical double-shell low-temperature tank, the gap between the inner tank side plate and the outer tank side plate is filled with a powdery cold insulating material such as perlite particles. Therefore, when performing construction work between the inner tank side plate and the outer tank side plate, such as modifying or adding an anchor, replacing or adding a purge ring, or welding around the edge of the inner tank side plate and bottom plate, it is necessary to use cold insulation material. Must be carried out of the tank. Therefore, the conventional method has been to extract the cold insulation material from a manhole provided at the bottom of the outer tank side plate, but the effort and time required to extract all the cold insulation material is enormous. ,Also,
If cold insulation material scatters, it will cause pollution and it also dislikes moisture, so the larger the amount, the more care must be taken when storing it after transport.

In order to solve this problem, partial extraction of the cold insulation material has been considered, and conventionally, as shown in FIGS. A partition plate 4 is inserted and the construction area is surrounded by the partition plate 4, and the partition plate 4 and the inner tank side plate 2 are separated.
and the gaps between the partition plates 4 are sealed with a filler 5 such as foamed urethane to prevent the cold insulation material 3 from entering the construction area. Construction is underway. However, this method also has the following problems.

[Problem that the invention seeks to solve]

In the conventional double-shell cryogenic tank construction method shown in FIGS. 4 and 5, reinforcing ribs 6 are placed on the lower side of the horizontal partition plate 3 to withstand the weight of the cold insulation material 3 on the partition plate 4. They must be arranged at appropriate intervals, and the placement of the partition plates 3 in the horizontal direction is limited to a small range in terms of strength. Therefore, it is not suitable for construction work that involves the entire circumference of the tank, such as replacing the purge ring 7. In addition, since the filling material 5 for sealing the gap also hardens the cold insulation material 3, the cold insulation material 3 is refilled in the construction area after the construction is completed.
As the cold insulation material 3 settles, voids may be generated on the lower side of the hardened cold insulation material 3, which may impair the cold insulation effect.

Therefore, an object of the present invention is to provide a construction method for a double-shell cryogenic tank that eliminates such conventional problems.

[Means for solving problems]

According to this invention, a construction method for a double-shell low-temperature tank is a construction method in which the construction area in the gap between the inner tank side plate and the outer tank side plate is surrounded by a partition plate, and the cold insulation material in this construction area is extracted and construction is performed. In this step, a slit is formed in the outer tank side plate at a position opposite to the horizontal joint part of the inner tank side plate, and a partition plate is inserted through this slit.
Connect the upper and lower parts of the slits on the outer tank side plate with a reinforcing jig, press the partition plate against the inner tank side plate with a pressing member to bring them into close contact, and connect the inner end of the partition plate to the horizontal joint of the inner tank side plate. It is characterized in that it is supported by a protrusion in the section.

[Effect]

The partition plate installed according to the construction method of the double-shell low temperature tank according to the present invention described above is supported by the protrusion of the horizontal joint part of the inner tank side plate, that is, the step of the joint part or the weld bead excess part. Therefore, it can withstand a considerably large load due to the cold insulation material.

Other objects, features and advantages of the invention will become apparent from the detailed description below, taken in conjunction with the accompanying drawings.

〔Example〕

FIG. 1 of the drawings shows an embodiment of the construction method for a double-shell cryogenic tank according to the present invention. In the illustrated embodiment, the lowest part of the gap between the inner tank side plate 2 and the outer tank side plate 1 of the double-shell low-temperature tank is to be constructed around the entire circumference of the tank. A horizontal slit 1 is made in the outer tank side plate 1 at approximately the same level as the horizontal joint part 10 between the second stage and the second stage.
1 is provided, and the partition plate 12 is inserted through the slit 11 so that its tip is in contact with the slightly upper side of the horizontal joint part 10 of the inner tank side plate 2. Next, a reinforcing jig 13 having a U-shaped cross section is welded to connect the upper and lower outer tank side plates 1 of the slit 11.
are provided at appropriate intervals to prevent a decrease in the strength of the outer tank side plate 1 due to the formation of the slits 11. This work is performed sequentially in the circumferential direction, and the partition plate 12 is arranged between the inner tank side plate 2 and the outer tank side plate 1 over the entire circumference of the tank. In addition, the gap between the partition plates 12 is
This can be solved by overlapping the edges of the two or inserting a thin plate through the slit 11 to cover the gap. A screw 14 extending in the tank radial direction is provided at the intermediate portion of each reinforcing jig 13, and this screw 14 presses the partition plate 12 against the inner tank side plate 2 via an angle 15. As a result, the inner tank side plate 2
and the partition plate 12 are in close contact with each other. After doing this,
Manhole 8 provided at the bottom of the outer tank side plate 1
The cold insulating material 3 is extracted from it using a vacuum device (not shown). At this time, the inner end of the partition plate 12 is the step of the joint part 10 if the thicknesses of the first and second inner tank side plates 2 are different, or the joint part if the thicknesses are the same. It is supported by a weld bead extra portion 16 (FIG. 2) at the top and is designed to withstand the load from the cold insulation material 3 above. After the removal of the cold insulation material 3 is completed, predetermined construction work is carried out in the construction area.

After the construction is completed, contrary to the procedure described above, return the cold insulation material 3 from the manhole 8 to the extent possible, remove the reinforcing jig 13, and pull out the partition plate 12.
The slit 11 is closed, and this operation is repeated in the circumferential direction to complete the entire operation.

Although this embodiment deals with a case where the lowest part is a construction area, the present invention can also be applied to a case where it is necessary to carry out construction in the middle part. That is, as shown in FIG. 3, corresponding to the horizontal joint part 10 of the inner tank side plate on the lower side of the construction area,
The partition plate 12 is arranged in the same manner as described above, and a partition plate 12' is also arranged at the horizontal joint section 10' above the construction area. After the construction area is thus surrounded by the upper and lower partition plates 12, 12', an opening 17 is provided at an appropriate position in the outer tank side plate 1, the cold insulation material 3 is extracted from the opening 17, and predetermined construction work is carried out. In this case, the lower partition plate 12 serves as a work floor.

Further, by inserting the vertical partition plate, the construction area is partially surrounded by the vertical partition plate and the horizontal partition plate 12, and it is also possible to partially extract the cold insulation material 3.

In the above embodiment, the partition plate 12 is pressed by the screws 14 provided on the reinforcing jig 13, but wedges may also be used, or other pressing devices may be used with the reinforcing jig. It can also be used by being attached to the outer tank side plate 1 separately from 13.

〔Effect of the invention〕

As described above, according to the present invention, the protruding part formed at the horizontal joint part of the inner tank side plate, that is, the step due to the difference in plate thickness and the weld bead excess part, supports the partition plate. Therefore, it can withstand considerably large loads, and construction work can therefore be carried out not only in a partial construction area but also in a wide construction area that extends around the entire circumference of the tank. In addition, in this invention, since the cold insulating material is not hardened using a filler, no voids are generated after refilling the cold insulating material.
This has the advantage that there is no risk that the cold insulation effect of the double-shell cryogenic tank will deteriorate after the construction is completed.

[Brief explanation of drawings]

Figure 1 is a partial cross-sectional view of a double-shell cryogenic tank showing the cold insulation material removed from the construction area by the double-shell cryogenic tank construction method according to the present invention, and Figure 2 is a partial cross-sectional view of the double-shell cryogenic tank at the end of the partition plate. FIG. 3 is an enlarged partial cross-sectional view of the horizontal joint of the inner tank side plate showing that the support is the weld bead excess. FIG. 4 and 5 are partial cross-sectional views of the double-shell cryogenic tank, respectively, showing the construction method of the conventional double-shell cryogenic tank, and FIG. 4 is a partial cross-sectional view of the double-shell cryogenic tank along the circumferential direction.
FIG. 5 is a partial sectional view along the radial direction. In the figure, 1: outer tank side plate, 2: inner tank side plate, 3: cold insulation material,
4, 12, 12': Partition plate, 5: Filler, 6: Reinforcing rib, 7: Purge ring, 8: Manhole,
10: Horizontal joint part, 11: Slot, 13: Reinforcing jig, 14: Screw, 15: Angle, 16: Weld bead extra part, 17: Opening.

Claims (1)

[Claims] 1. The construction area in the gap between the inner tank side plate and the outer tank side plate filled with powdery cold insulation material is surrounded by a partition plate, and the cold insulation material in the gap surrounded by the partition plate is extracted and construction is carried out. In the construction method for a heavy-shell low-temperature tank, a horizontal slit is formed in the outer tank side plate corresponding to the horizontal joint of the inner tank side plate, a partition plate is inserted through the slit, and the upper outer tank side plate and the lower The side and outer tank plates are connected using a reinforcing jig, the partition plate is pressed against the inner tank side plate by a pressing member so that they come into close contact with each other, and the inner end of the partition plate is supported by the protrusion of the horizontal joint part. A construction method for a double-shell low-temperature tank characterized by: