JPH09209583A - Tank dismantling construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dismantling construction method which is capable of shortening a working period and reducing working cost without temporarily installing large-scale working scaffolds. SOLUTION: An air bag 5 in a slackened condition is carried into a tank 1, air is guided into the air bag 5 to be inflated, water 13 is filled in the tank 1 to adhere the air bag 5 to a tank roof 2 and the weight of the tank roof 2 is being supported by the buoyancy of the air bag 5 to cut the tank roof 2 at a smaller diameter than the inner diameter of a tank side plate 3. The water 13 in the tank 1 is drained in stages to decrease a water level so that disassembling work for the tank side plate 3 can be done at the top of the tank roof 2 while dropping the tank roof 2 and then disassembling work for the tank roof 2 seated on a tank bottom 17 can be done after almost all of the tank side plate 3 is disassembled.

Description

Detailed Description of the Invention

[0001]

The present invention relates to petroleum, LPG, L
The present invention relates to a tank dismantling method for storing NG or the like.

[0002]

2. Description of the Related Art When rebuilding or removing a large tank for storing petroleum, LPG, LNG or the like, it is necessary to disassemble the tank into a size that can be transported by loading it on a truck or the like. .

Conventionally, in the case of disassembling such a tank, a work scaffold is temporarily provided around the tank, and the worker uses the work scaffold to sequentially cut from a superstructure of the tank to an appropriate size with a burner. However, the work of hanging it on the ground with a large crane was repeated.

[0004]

However, in such a conventional dismantling method, a work scaffold that must be temporarily installed around the tank becomes a large scale, and a large amount of labor and time are required for the temporary work, and the construction period is short. There has been a problem that the construction cost increases as it becomes longer.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a tank dismantling method capable of shortening the construction period and the construction cost by eliminating the need for temporary provision of a large-scale work scaffold.

[0006]

According to the present invention, an air bag is carried into a tank in a deflated state, air is introduced into the air bag to expand the air bag, and then water is poured into the tank to fill the air bag. The air bag is closely attached to the tank roof, the weight of the tank roof is supported by the buoyancy of the air bag, the tank roof is cut with a diameter smaller than the inner diameter of the tank side plate, and the water in the tank is gradually drained. While lowering the tank roof by lowering the water level, the tank side plate is disassembled from above the tank roof, and after that,
The present invention relates to a tank dismantling method, which dismantles a tank roof laid on the bottom of a tank by dismantling most of the tank side plates.

In this way, the tank side plate can be disassembled from the tank roof, so that it is not necessary to temporarily install a large-scale work scaffold around the tank as in the conventional case.

In addition, the dismantling work of the tank roof, which has been conventionally performed at a high place where workability is poor, can be performed on the ground.

Further, when the tank side plate is disassembled from the tank roof, a temporary crane is installed on the tank roof and the cut pieces of the tank side plate are hung on the ground using the temporary crane. You can

With this arrangement, the work of cutting the tank side plate and the work of lifting the cut pieces are facilitated, and it is not necessary to arrange a large crane on the ground as in the conventional case.

[0011]

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

1 to 7 show an example of an embodiment for carrying out the present invention. In this embodiment, an outer tank 1a and an inner tank 1 are provided.
The case of a tank 1 having a double shell structure composed of b and b is shown, and a tank roof 2 of the tank 1 is constituted by respective roof portions 2a and 2b of an outer tank 1a and an inner tank 1b, and a tank side plate 3 Is the side plate portions 3a, 3 of the outer tank 1a and the inner tank 1b, respectively.
b.

When disassembling the double shell structure tank 1 as described above, the stored liquid and vaporized gas in the tank 1 are first evacuated to an empty state, and then the outer tank 1a and the inner tank 1b.
The suction material such as perlite filled in between is sucked and discharged by a vacuum method. After that, the atmosphere in the tank 1 is replaced with air, and the internal accessories (liquid level gauge, thermometer, Nozzle).

When the dismantling preparation is completed as described above, FIG.
As shown in FIG. 2, the airbag 5 is carried into the tank 1 from the manhole 4 below the tank side plate 3 in a deflated state, and then drawn into the tank 1 through the manhole 6 at the center of the tank roof 2 as shown in FIG. The air introduction pipe 7 is connected to the air bag 5, and the air bag 5 is inflated by introducing air 9 from the outside of the tank 1 with an air pump 8.

When the air bag 5 is sufficiently inflated, the air introducing pipe 7 is closed by a valve 10 to seal the air bag 5 as shown in FIG. 3, and the stored liquid remaining in the lower portion of the tank side plate 3 is discharged. Water 13 is introduced into the tank 1 from the nozzle 11 of the tank 1 through the pump 12 so that the air bag 5 is closely attached to the tank roof 2 (the roof portion 2b of the inner tank 1b).
3 is set up so that the weight of the tank roof 2 can be supported by the buoyancy of the airbag 5.

In this state, as shown in FIG. 4, the valve 14 of the nozzle 11 is closed and the pump 12 is removed.
After installing an appropriate number of temporary cranes 15 on the tank roof 2 (on the roof portion 2a of the outer tank 1a), the tank roof 2
Is cut with a diameter slightly smaller than the inner diameter of the tank side plate 3 (the inner diameter of the side plate portion 3b of the inner tank 1b).

In this embodiment, since the tank roof 2 is composed of the roof portions 2a and 2b of the outer tank 1a and the inner tank 1b, the outer tank 1a is cut before the tank roof 2 is cut. It goes without saying that the roof portions 2a and 2b of the inner tank 1b are integrally connected to each other by a connecting member (not shown).

Next, as shown in FIG.
The valve 14 of the tank 1 is opened, and the water 13 in the tank 1 is gradually drained to lower the water level so that the tank roof 2 is mounted on the airbag 5 and lowered while the tank side plate 3 is disassembled from above the tank roof 2. Then, the cut pieces 16 of the tank side plate 3 are hung on the ground.

In this way, when the disassembly of the tank side plate 3 is advanced from the upper side, as shown in FIG.
Is in a state of landing on the tank bottom 17, the valve 10 of the air introducing pipe 7 which is still connected to the airbag 5 is opened to gradually discharge the air 9 in the airbag 5, As shown in, the airbag 5 is deflated and the tank roof 2 is landed on the tank bottom portion 17.

As for the tank roof 2 which is landed on the tank bottom 17, the dismantling work may be advanced on the ground,
The dismantling work of the tank 1 is completed by dismantling the tank roof 2.

Therefore, according to the above embodiment, the airbag 5 in which the cut tank roof 2 is floated on the water 13 in the tank 1
Since it is possible to perform the dismantling work of the tank side plate 3 from above the tank roof 2 while lowering the tank roof 2 by using a simple means of lowering the water level by supporting the buoyancy of the tank and draining the water 13 in the tank 1. Since it is not necessary to temporarily install a large-scale work scaffold around the tank 1 as in the conventional case, it is possible to reduce the construction period and the construction cost.

Further, the tank roof 2 can be disassembled efficiently and safely because the tank roof 2 can be dismantled on the ground, which has been conventionally performed at a high place where workability is poor.

Further, when the tank side plate 3 is disassembled from the tank roof 2 as in this embodiment, a temporary crane 15 is installed on the tank roof 2 and the temporary crane 15 is used to If the cutting piece 16 of the tank side plate 3 is hung on the ground, the cutting work of the tank side plate 3 and the hanging work of the cutting piece 16 can be easily coordinated.
The tank side plate 3 can be disassembled efficiently, and moreover,
There is no need to arrange a large crane on the ground as in the conventional case, and the cut piece 16 of the tank side plate 3 can be hung on the ground simply by installing a small temporary crane 15 on the tank roof 2, further reducing the construction cost. can do.

The method of dismantling the tank of the present invention is not limited to the above-mentioned embodiment, and a tank having a double shell structure is illustrated in the figure, but it is also applicable to a tank having a single shell structure. It goes without saying that various changes can be made without departing from the scope of the present invention.

[0025]

According to the tank dismantling method of the present invention described above, various excellent effects as described below can be obtained.

(I) While supporting the cut tank roof by the buoyancy of an air bag floating on the water in the tank and draining the water in the tank to lower the water level, while lowering the tank roof, Since the tank side plate can be disassembled from the top of the tank, it is not necessary to temporarily install a large-scale work scaffold around the tank as in the conventional case, thereby shortening the construction period and reducing the construction cost.

(II) The tank roof can be disassembled efficiently and safely because the tank roof dismantling work, which was conventionally performed in a high place where workability is poor, can be performed on the ground.

(III) When disassembling the tank side plate from the tank roof, a temporary crane is installed on the tank roof, and the cut pieces of the tank side plate are hung on the ground using the temporary crane. If this is done, the work of cutting the tank side plate and the work of lifting the cut pieces can be facilitated, so that the tank side plate can be dismantled efficiently, and it is necessary to place a large crane on the ground as in the past. Since the cut pieces of the tank side plate can be hung on the ground simply by installing a small temporary crane on the tank roof, the construction cost can be further reduced.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a carried-in state of an airbag according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a state where the airbag of FIG. 1 is inflated.

FIG. 3 is a schematic view showing a state in which water is filled in the tank of FIG.

FIG. 4 is a schematic view showing a state where the tank roof of FIG. 3 is cut.

5 is a schematic view showing a state where the tank roof of FIG. 4 is lowered.

FIG. 6 is a schematic view showing a state in which the airbag of FIG. 5 is landed on the bottom of the tank.

FIG. 7 is a schematic view showing a state where the tank roof of FIG. 6 is landed on the bottom of the tank.

[Explanation of symbols]

 1 Tank 2 Tank Roof 3 Tank Side Plate 5 Airbag 9 Air 13 Water 15 Temporary Crane 16 Cutting Piece 17 Tank Bottom

Claims (2)

[Claims] 1. An air bag is carried into a tank in a deflated state, air is introduced into the air bag to expand the air bag, and then water is filled in the tank to bring the air bag into close contact with the tank roof. The tank roof is cut by a diameter smaller than the inner diameter of the tank side plate with the weight of the tank roof supported by the buoyancy of the airbag, and the water level in the tank is gradually reduced to lower the water level. The tank side plate is dismantled from above the tank roof while lowering the tank, and after that, most of the tank side plate is dismantled to perform the dismantling work of the tank roof landed on the bottom of the tank. Tank dismantling method. 2. When a tank side plate is dismantled from the tank roof, a temporary crane is installed on the tank roof, and the cut pieces of the tank side plate are hung on the ground using the temporary crane. The tank dismantling method according to claim 1.