JPH0123630B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for constructing a double-shelled cylindrical tank constructed by stacking an inner tank and an outer tank at a predetermined interval, each having a bottom plate, a side plate, and a roof.

Prior Art The general structure of a double shell cylindrical tank is as shown in Fig. 1, which includes an outer tank bottom plate 1, an outer tank side plate 2, and an outer tank roof 7.
an outer tank, an inner tank bottom plate 16, and an inner tank side plate 1.
4. An inner tank having an inner tank roof 5 is stacked on top of each other at a predetermined distance. The inner tank bottom plate 16 is a bottom cold insulation layer 15 laid on the outer tank bottom plate 1.
Although the inner tank side plate 14 is placed on top of the tank, the surrounding area that is joined to the lower end of the inner tank side plate 14 is subject to repeated stress concentration due to the repeated filling and emptying of the tank. It's getting thicker. This part is called an annular plate 4. Annular plate 4
Since the liquid pressure of the stored liquid and the weight of the inner tank side plate 14 and the inner tank roof 5 are applied to the tank, the annular bottom cold insulating layer 3 below the inner tank side plate 14 is made stronger than the other parts.
Further, the upper end of the inner tank side plate 14 and the peripheral part of the inner tank roof 5 are connected via a knuckle plate 6 having a curved surface. A cold insulation material is inserted between the inner tank side plate 14 and the outer tank side plate 2 and between the inner tank roof 5 and the outer tank roof 7 to form a cold insulation layer.

To describe the conventional general construction method of a double shell cylindrical cryogenic tank having such a configuration, as shown in FIG. 2, first, the outer tank bottom plate 1 and the outer tank side plate 2 are assembled,
Next, an annular bottom cold insulating layer 3 and an annular plate 4 for the inner tank bottom plate are constructed on the bottom plate 1, and an inner tank roof 5 and a knuckle plate 6 are then assembled on the bottom plate, leaving a required gap thereon. The outer tank roof 7 is assembled integrally, and the inner and outer tank roofs 5 and 7, which have been assembled above ground, are raised to a predetermined position along the outer tank side plate 2, and then the inner tank side plate 14 and the bottom cold insulation layer 1 are assembled.
5 and assemble the inner tank bottom plate 16 thereon.
As shown in FIG. 2, the means for raising the inner and outer tank roofs 5, 7 is as follows: compressed air is sent into the tank by a blower 11, and air pressure is applied to the lower surface of the roof 7 to raise the roofs 7, 5. Air razing methods and mechanical or hydraulic jack up methods are used.

Next, using the assembled outer tank roof 7, a small carrier such as a trolley hoist 13 (see Figure 3 e) is installed, and the inner tank side plates 14 are assembled, and then the inner and outer tank roofs are assembled. The connecting hanging device 9 is extended, the knuckle plate 6 and the roof 5 are lowered onto the side plate 14, and after the skins are aligned, they are assembled by welding and fixing.

With the above conventional construction method, the inner tank side plate 14, which requires a long construction period, can be assembled under the outer tank roof, and is not affected by weather conditions such as wind, rain, snow, etc.
It is advantageous in terms of quality and process control, and after completing the assembly of the outer tank roof, civil engineering work such as paving can be carried out inside the dike surrounding the tank, with some exceptions. The advantage was that it could be started as early as possible.

However, due to recent social demands, LNG,
From the standpoint of improving the safety of the above-mentioned type of low-temperature double-shell tanks that store large quantities of low-temperature liquids such as LPG,
The amount of civil engineering work is increasing, such as improving the strength of the dike, paving the dike and its interior, and installing insulation materials on the inside of the dike.The conventional tank construction method described above requires the entire process to be carried out by civil engineering work. This creates a need to extend the period by the amount of the increase.

Purpose The present invention eliminates the above-mentioned problems in the conventional method of constructing a flat-bottomed cylindrical tank, and enables early start of civil engineering work around the tank.
The purpose of the present invention is to provide a construction method for a double-shelled cylindrical tank that not only makes it possible to shorten the overall process of tank construction work, but also contributes to improving quality and workability.

Structure According to the construction method of the present invention in accordance with the above object, after the assembly of the outer tank bottom plate of a double shell cylindrical tank is completed, the annular part of the bottom cold insulation layer, the inner tank annular plate, and the outer tank side plate are assembled on the same bottom plate. We started assembling the bottom tier and the inner tank roof, and started assembling the outer tank roof immediately after temporary assembly, without waiting for the completion of the inner tank roof assembly, which requires a long period of time for welding and inspection. Before the roof frames and roof plates were completed, the assembly of the outer tank side panels and roof was completed, and the knuckle plates were fixed to the lower part of the outer tank roof at approximately predetermined intervals via a hanging device. After that, the outer tank roof is raised by lifting means such as air raising or jack up and fixed to the upper end of the outer tank side plate, and then the inner tank side plate, inner tank roof and inner tank bottom plate are assembled, and then the top of the inner tank side plate is fixed to the upper end of the outer tank side plate. The present invention is characterized in that after the knuckle plate is lowered and fixed, the inner tank roof is raised by a lifting means and attached to the tip of the knuckle plate at a predetermined position.

Hereinafter, the present invention will be explained in detail based on embodiments shown in the drawings.

3a, b, c, d, e, f, and g are diagrams showing an embodiment of the method for constructing a double shell cylindrical tank according to the present invention in the order of steps.

As shown in figure a, on the foundation that has been poured on the site in advance,
Assemble the outer tank bottom plate 1, the lower part of the outer tank side plate 2, the annular bottom cold insulation layer 3, and the inner tank annular plate 4.

Next, as shown in Figure b, after placing the inner tank roof 5 and the knuckle plate 6 on an assembly frame (not shown), the inner tank roof 5 is temporarily assembled, and the knuckle plate 6 is welded and inspected. complete.

Next, as shown in Figure c, the outer tank roof 7 is assembled on the frame 8 on the inner tank roof 5, and on the other hand, after completing the assembly of the outer tank side plates 2, the knuckle plate 6 is attached to the outer tank as shown in Figure d. Attach the roof airtight seal 10 to the outer tank roof 7 while connected to the roof 7 with a hanging device 9 having a length adjustment device such as a turnbuckle 9a,
By feeding compressed air into the tank using a blower 11 or the like, the pressure inside the tank is increased, and the outer tank roof 7 is fixed at a predetermined position at the upper end of the outer tank side plate 2 by air raising. In addition, the above-mentioned Knuckle Plate 6,
In order to shorten the construction period, it is desirable that the inner and outer tank roofs 5 and 7 be made into large blocks to reduce the number of on-site welding points at the installation site. In addition, without waiting for the completion of welding and inspection of the knuckle plate 6, some or all of the joints may be temporarily assembled by on-site welding,
It goes without saying that it is also possible to adopt the process of lifting the roof as described above and then performing welding and inspection.

As mentioned above, once the outer tank roof is completed, it becomes possible to hand over the site around the tank to the civil engineering construction side, except for the liquid dike and the site inside the dike on the side of the construction opening 17 of the outer tank side plate.

Subsequently, as shown in Fig. e, the inner tank roof 5, the inner tank side plates 14, and the center part of the bottom cold insulation layer 15 are continuously constructed using the trolley hoist 13 provided on the outer tank roof 7, and the inner tank side plates After completing the assembly of 14, as shown in Fig. f, the knuckle plate 6 connected to the outer tank roof 7 is lowered, and after making skin contact with the inner tank side plate 14, a welding inspection is performed, and then the hanging device 9 is removed. do.
Also, the assembly, welding, and inspection of the inner tank bottom plate 16 are completed.

When aligning the inner tank side plate 14 and the knuckle plate 6, only the knuckle portion is installed.
Since the inner tank roof 5 is not integrated as in the conventional construction method, not only is the installation very easy, but if the knuckle plate 6 is tack welded and fine adjustment is possible, the inner tank side plate 14 This further facilitates the installation of the Knuckle plate 6. Furthermore, it is also conceivable to perform surface alignment with the knuckle plate 6 before completing the welding and inspection of the uppermost layer of the inner tank side plate 14. In addition, in this embodiment, as described above, the knuckle plate 6 is connected to the turnbuckle 9a of the hanging device.
However, it is also possible to install a temporary jack on the outer tank side plate 2 and use this to lower the tank.

Next, as shown in Fig. g, the inner tank roof 5 is lifted by lifting means such as air raising or jacking up, and the tank is completed by installing it at a predetermined position at the tip of the knuckle plate 6 on the upper part of the inner tank side plate 14.

Effects As described above, according to the present invention, during the construction process of a flat-bottomed cylindrical tank, it is possible to start assembling difficult-to-handle parts such as the inner tank roof and the knuckle plate in the tank at an early stage, while also reducing welding and inspection. Prioritizing the completion of the outer tank side panels and the outer tank roof without waiting for the completion of the work, the Katsukuru plate was suspended from the outer tank roof and lifted upwards, and the inner tank side panels were assembled and then lowered and installed. By completing the inner tank roof afterwards, the site around the tank can be constructed several months earlier than with conventional construction methods, and welding of inner tank materials other than the inner tank annual plate is now possible. This makes it possible to carry out inspections after the installation of the outer tank roof, which is not affected by weather conditions such as wind, rain, or snow, and is highly effective in terms of process control.

[Brief explanation of drawings]

Figure 1 is a sectional view showing the schematic structure of a typical double-shelled cylindrical tank, Figure 2 is a schematic diagram explaining the conventional construction method for the tank, Figures 3 a, b, c,
d, e, f, and g are schematic diagrams illustrating the construction method of the embodiment of the present invention in the order of steps. 1... Outer tank bottom plate, 2... Outer tank side plate, 3... Annular part bottom cold insulation layer, 4... Annular plate, 5... Inner tank roof, 6... Knuckle plate, 7... Outer tank roof,
8... Frame, 10... Seal member, 9... Hanging device, 1
1...Blower (roof lifting means), 14...Inner tank side plate,
15...Bottom cold insulation layer, 16...Inner tank bottom plate.

Claims (1)

[Claims] 1. An inner tank and an outer tank each having a bottom plate, a side plate, and a roof are stacked one on top of the other at a predetermined interval, and the inner tank bottom plate is placed on a bottom cold insulation layer provided on the outer tank bottom plate, and the inner tank The peripheral part of the inner tank bottom plate to which the lower end of the side plate is connected is formed of an annular plate that is thicker than the other parts of the inner tank plate, and the bottom annular plate is placed on the annular part of the bottom cold insulation layer. In the construction method for a double-shell cylindrical tank in which the top of the inner tank side plate and the inner tank roof periphery are connected by a curved knuckle plate, after the assembly of the outer tank bottom plate is completed, the same bottom plate is On the top, the bottom cold insulation layer annular part, the inner tank annular plate,
Started assembling the bottom of the outer tank side panels and the inner and outer tank roofs.
Prior to completion of the inner tank roof, the assembly of the outer tank side plates and the outer tank roof is completed, and after fixing the knuckle plate to the lower part of the outer tank roof at approximately a predetermined interval via a hanging device, The outer tank roof is raised by a lifting means and fixed to the upper end of the outer tank side plate, and then the inner tank side plate, the inner tank roof, and the inner tank bottom plate are assembled,
Thereafter, after lowering and fixing the knuckle plate to the top of the inner tank side plate, the inner tank roof is raised by a lifting means, and the tip of the knuckle plate is attached to a predetermined position. Construction method of cylindrical tank.