JPH0435591B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for replacing the bottom parts of a double-shell tank, such as the bottom plates of the inner and outer tanks and the bottom cold insulation material.

[Conventional technology]

Liquefied petroleum gas (LPG) and liquefied natural gas (LNG)
A double-shell tank is one of the storage facilities for such low-temperature liquids.

As shown in FIG. 1a, for example, this double-shell tank has an outer tank 3 installed on a foundation 2 that is set apart from the ground 1, and an inner tank connected to the outer tank 3 via a bottom cold insulating material 4. 5 is installed, and a heat insulating cold insulating material 6 such as pearlite grains is filled between the inner and outer tanks.

The outer tank 3 of such a double shell tank has an outer tank bottom plate 3.
a, an outer tank side plate 3b and an outer tank roof 3c; similarly, the inner tank 5 also includes an inner tank bottom plate 5a and an inner tank side plate 5b.
and an inner tank roof 5c, and usually has a welded structure.

[Problem that the invention seeks to solve]

If such a double-shelled tank is used for a long period of time, corrosion may occur in the outer tank bottom plate 3a due to moisture entering between the foundation 2 and the outer tank bottom plate 3a, and it may need to be replaced. may occur.

In addition, if low-temperature liquid leaks from the inner tank bottom plate 5a due to an internal defect in the material that cannot be discovered at the construction stage, or if the bottom cold insulating material 4 interposed between the outer tank bottom plate 3a and the inner tank bottom plate 5a If frost forms on the outer periphery of the lower end of the outer tank side plate 3b due to a decrease in the heat insulation effect, the inner tank bottom plate 5a and the bottom cold insulating material 4 will need to be replaced.

However, in such a double-shell tank, the outer tank 3 and the inner tank 5 have a double-shell structure, and a heat insulating material 6 such as perlite grains is filled between the inner and outer tanks, so the conventional single-shell oil Unlike tanks, gas holders, etc., the bottom portions of the outer tank bottom plate 3a, the inner tank bottom plate 5a, the bottom cold insulating material 4, etc. cannot be easily replaced.

This invention was made in view of the problems of the prior art, and is a method for replacing the bottom part of a double-shell tank, which allows the bottom parts of the double-shell tank, such as the bottom plates of the inner and outer tanks and the bottom cold insulation material, to be safely and easily replaced. This is what we are trying to provide.

[Means for solving problems]

In order to solve the above-mentioned problems, the first invention provides an insulating and cold insulating material from a hole formed in the side plate of the outer tank when replacing the bottom part of a double shell tank which is equipped with an inner and outer tank and is filled with an insulating and cold insulating material between the inner and outer tanks. After removing the material,
The roofs of the inner and outer tanks are connected with rods, and then the outer tank side plates are cut around the entire circumference near the inner tank bottom plate. A workbench with a height corresponding to the cutting position is installed close to the outer tank, and then the outer tank is cut. An air bag was attached to surround the cut section, and then compressed air was supplied to the air bag and the outer tank to float the inner and outer tanks while transferring it onto the workbench, removing the remaining outer tank bottom plate and bottom cold insulation material. The second invention is characterized in that, when replacing the bottom part of a double-shell tank, which is provided with an inner and outer tank and is filled with an insulating cold material between the inner and outer tanks, After removing the heat insulating material from the hole formed in the outer tank side plate, connect the roofs of the inner and outer tanks with rods, then cut the outer tank side plate all around above the inner tank bottom plate, and install an air bag to surround this cut. After the inner and outer tanks are attached and supported by floating in one piece, the entire circumference of the inner tank side plate is cut, and then at least the inner tank bottom plate is replaced while the inner and outer tanks without a bottom plate are floated with an air bag. be.

[Effect]

When replacing the bottom part of a double shell tank, connect the roofs of the inner and outer tanks with rods to make the inner and outer tanks into one.
After cutting the lower part of the outer tank side plate at the level of the inner tank bottom plate, these inner and outer tanks are floated and moved, and the remaining outer tank bottom plate and bottom cold insulation material are replaced.
Alternatively, the roofs of the inner and outer tanks can be connected with rods to make the inner and outer tanks into one body, the lower part of the outer tank side plate is cut above the inner tank bottom plate and then supported by floating, and the lower part of the inner tank side plate is cut and the bottom The inner and outer tanks are kept floating while replacing the inner tank bottom plate, outer tank bottom plate, or bottom cold insulating material.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a process diagram of an embodiment of the method for replacing the bottom portion of a double shell tank according to the present invention.

This double shell tank, as shown in Figure 1a,
An outer tank 3 is installed on a foundation 2 set apart from the ground 1, an inner tank 5 is installed inside this outer tank 3 via a bottom cold insulator 4, and a heat insulating cold insulator 6 such as perlite grains is installed between the inner and outer tanks. It is filled with and configured.

When replacing both or either one of the outer tank bottom plate 3a and the bottom cold insulating material 4 of such a double shell tank, first, as shown in FIG. 7, and the heat insulating cold insulating material 6 filled between the inner and outer tanks is removed from the working hole 7.

After this, as shown in Fig. 1c, a worker enters between the inner and outer tanks, connects the outer tank roof 3c and the inner tank roof 5c with a number of rods 8, and integrates the inner and outer tanks at least in the vertical direction. At the same time, remove anchor bolt 9.

Next, as shown in FIG. 1d, the outer tank side plate 3b
The lower part of the tank is cut all around at the level of the inner tank bottom plate 5a.
In the state where the outer tank side plate 3b is cut in this way, the upper part of the cut part 10 of the outer tank side plate 3b and the outer tank roof 3
c is supported by the inner tank 5 via a rod 8.

After this, a workbench 11 is placed on the ground 1 outside the outer tank 3.
The height of the mound is made to be almost the same as the height up to the cut portion 10 of the outer tank side plate 3b, and its width is equal to the diameter of the outer tank 3 plus the working space. An inclined surface is formed at the tip.

Further, the working hole 7 formed in the outer tank side plate 3b is closed.

Next, as shown in FIG. Compressed air is sent into the tank 3 to float the outer tank 3, and at the same time, the integral inner tank 5 is also floated via the rod 8. At this time, in order to prevent the inner tank 5 from being deformed by the compressed air supplied to float the outer tank 3, compressed air whose pressure is slightly lower than that of the compressed air sent into the outer tank 3 is put into the inner tank 5 to change the shape. Try to keep it.

Thereafter, the floating outer tank 3 and inner tank 5 are moved along with the air bag 12 over the workbench 11 and moved from above the bottom cold insulating material 4.

After moving the outer tank 3 without a bottom plate and the inner tank 5 with a bottom plate in this way, as shown in FIG. Replace one side.

After replacing the bottom cold insulating material 4 or the outer tank bottom plate 3a with a new one in this way, the double shell tank is rebuilt by carrying out the restoration work in the reverse process to the above.

Work is carried out according to the above steps, and the roof 4c of the outer tank 4 and the roof 5c of the inner tank 5 are connected with the rod 8 to integrate the outer tank 4 and the inner tank 5, and the outer tank side plate 3b is assembled.
After cutting the lower part of the tank at the level of the inner tank bottom plate 5a, the outer tank 4 and inner tank 5 are floated and moved, so it is relatively easy to cut the outer tank, which is the bottom part of the double shell tank. Tank bottom plate 3a and bottom cold insulation material 4
can be replaced.

Next, another embodiment of the present invention will be specifically described with reference to FIG. 2 of the drawings.

In this embodiment, the outer tank bottom plate 3a shown in FIG.
In addition to the bottom cold insulator 4, the entire bottom including the inner tank bottom plate 5a is replaced.

First, as shown in FIG. 2b, a working hole 7 is made in the lower part of the outer tank side plate 3b, and the heat insulating cold insulating material 6 filled between the inner and outer tanks is removed from this working hole 7.

After this, as shown in Fig. 2c, a worker enters between the inner and outer tanks, connects the outer tank roof 3c and the inner tank roof 5c with a number of rods 8, and integrates the inner and outer tanks at least in the vertical direction. At the same time, remove anchor bolt 9.

Next, as shown in FIG. 2d, the outer tank side plate 3b
The lower part of the tank is cut around the entire circumference slightly above the inner tank bottom plate 5a, and the outer tank side plate 3b and the outer tank roof 3c above the cut portion 10 are supported by the inner tank 5 via rods 8.

After this, a mound of earth is built around the outer tank 3 to serve as a workbench 11, and its height is made slightly lower than the cutting part 10, and this workbench 11 is used to create the cutting part 11 of the outer tank side plate 3b. An air bag 12 is installed higher up to make the outer tank 3 airtight.

Then, compressed air is sent into the air bag 12 and the outer tank 3 to levitate and support the outer tank 3 whose bottom plate has been cut and the inner tank 5 with an integral bottom plate through the outer tank 3 and the rod 8, and from inside the inner tank 5. The lower part of the inner tank side plate 5b is cut around the entire circumference slightly above the inner tank bottom plate 5a.

Therefore, in this state, the outer tank 3 without a bottom plate
The inner tank 5 without a bottom plate is floated by the compressed air supplied into the air bag 12 and the outer tank 3.

Next, as shown in FIG. 2e, with the outer tank 3 without a bottom plate and the inner tank 5 without a bottom plate suspended and supported, all of the remaining inner tank bottom plate 5a, bottom cold insulation material 4, and outer tank bottom plate 3a are removed. , or at least the inner tank bottom plate 5
Replace a.

After replacing the inner tank bottom plate 5a or the bottom cold insulating material 4 or the outer tank bottom plate 3a with a new one, the double shell tank is rebuilt by carrying out the restoration work in the reverse order to the above.

In this way, the outer tank side plate 3b and the inner tank side plate 5
By cutting the entire circumference of b, and integrating the inner and outer tanks without a bottom plate with rods 8 and supporting them in a floating state, it is relatively easy to remove the inner tank bottom plate 5a, which is the bottom part of the double shell tank, and the bottom cold insulation material. 4. The outer tank bottom plate 3a can be replaced.

In each of the above embodiments, the work platform is constructed of earthen mounds, but it may also be constructed of temporary scaffolding or the like.

Further, although the inner tank bottom plate is replaced while the inner and outer tanks without the bottom plate are floated, the work may be performed by moving from above the bottom plate in this case as well.

〔Effect of the invention〕

As described above in detail with the embodiments, according to the present invention, when replacing the bottom part of a double shell tank, the roofs of the inner and outer tanks are connected with rods to integrate the inner and outer tanks, and the outer tank side plate is After cutting the lower part at the level of the inner tank bottom plate, these inner and outer tanks are floated and moved, so the remaining outer tank bottom plate and bottom cold insulation material can be replaced, which is different from conventional double shell tanks. In some cases, it has become possible to replace the bottom part, which used to be difficult.

In addition, when replacing the bottom of a double shell tank, connect the roofs of the inner and outer tanks with rods to make the inner and outer tanks into one, cut the lower part of the outer tank side plate above the inner tank bottom plate, and then float it and support it. In addition, the lower part of the inner tank side plate was cut to maintain the bottomless inner and outer tanks in a floating state, so all bottom parts of the outer tank bottom plate and bottom cold insulation material, including the inner tank bottom plate, were replaced. became possible.

Therefore, the life of the double shell tank can be extended and it is economical.

Further, the bottom portion of the double shell tank can be replaced safely and easily.

[Brief explanation of drawings]

FIGS. 1 and 2 are process diagrams of an embodiment of the method for replacing the bottom portion of a double-shelled tank according to the present invention. 1...Ground, 2...Foundation, 3...Outer tank, 3a...
...Outer tank bottom plate, 3b...Outer tank side plate, 3c...Outer tank roof, 4...Bottom cold insulation material, 5...Inner tank, 5a...Inner tank bottom plate, 5b...Inner tank side plate, 5c...Inside tank roof,
6... Insulating cold insulation material, 7... Working hole, 8... Rod, 9... Anchor bolt, 10... Cutting part, 1
1...Workbench, 12...Air bag.

Claims (1)

[Scope of Claims] 1. When replacing the bottom part of a double-shelled tank that has an inner and outer tank and is filled with a heat insulating cold insulating material between the inner and outer tanks, after removing the heat insulating cold insulating material from a hole formed in the side plate of the outer tank, The roofs of the inner and outer tanks are connected with rods, and then the outer tank side plates are cut around the entire circumference near the inner tank bottom plate. A workbench with a height corresponding to the cutting position is installed close to the outer tank, and then the outer tank is cut. An air bag was attached to surround the cut section, and then compressed air was supplied to the air bag and the outer tank to float the inner and outer tanks while transferring it onto the workbench, removing the remaining outer tank bottom plate and bottom cold insulation material. A method for replacing the bottom part of a double shell tank, characterized in that at least one of the following is replaced. 2 When replacing the bottom of a double-shelled tank with an inner and outer tank and an insulating and cold insulating material filled between the inner and outer tanks, the insulating and cold insulating material was removed from the hole formed in the side plate of the outer tank, and then the roofs of the inner and outer tanks were rodded. Then, the outer tank side plate is cut around the entire circumference above the inner tank bottom plate, an air bag is attached to surround this cut part to levitate and support the inner and outer tanks as one, and then the inner tank side plate is cut around the entire circumference. A method for replacing the bottom part of a double shell tank, characterized in that at least the bottom plate of the inner tank is replaced while the inner and outer tanks without a bottom plate are floated up using an air bag.