JPS6335790B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for repairing an oil tank whose bottom plate has corroded and has become unusable or nearly unusable.

Generally, as shown in Figure 1, an oil tank is constructed by laying a bottom plate 1 on the ground, joining a side plate 2 in a cylindrical shape to the bottom plate 1, and joining a roof 3 to the upper end of the side plate 2. . In such a configuration, the bottom plate 1
Since it is in direct contact with the ground, corrosion will occur on the lower surface of the bottom plate 1 due to the influence of groundwater, etc., and if this condition continues for a long period of time, holes will open in the bottom plate 1, causing accidents such as oil leakage. Therefore, in order to prevent this, the state of corrosion is periodically inspected, and if the thickness of the bottom plate 1 becomes thinner than an allowable value due to corrosion, repair is performed. Conventionally, repairs have been carried out by replacing the bottom plate 1, but such a method has the disadvantage that it takes time and effort to remove the old bottom plate 1. In particular, the lower surface of the joint with the side plate 2 is susceptible to corrosion due to thermal deterioration during welding, and re-covering such a portion requires a great deal of effort. Furthermore, even if the bottom plate is replaced, the new bottom plate will also touch the ground, so it will eventually corrode.

This invention was made in view of the above points,
To provide a method for repairing an oil tank that does not require the trouble of replacing an old bottom plate and can be made more sturdy and less prone to corrosion than the original bottom plate of the tank.

According to this invention, the old bottom plate is left as it is without being removed, concrete is poured on top of the old bottom plate in the tank, and on top of the concrete,
A new bottom plate is installed and the peripheral edge of this new bottom plate is joined to the tank side plate. This method saves the trouble of removing the old bottom plate, and since the new bottom plate is laid on top of the concrete and does not come into contact with the ground, it is less likely to corrode, and the old bottom plate and concrete also support the liquid load. The new bottom plate itself can be made thinner.

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

FIG. 2 shows an embodiment of the repair method according to the present invention. As shown in Figure 2a, in the existing tank, a bottom plate 1 is laid on the ground, a side plate 2 is joined to the bottom plate 1 in a cylindrical shape, and a roof 3 is attached to the upper end of the side plate 2.
are joined.

When repairing the bottom plate 1, first drain all the oil from the tank. Next, as shown in FIG. 2b, concrete 4 is poured onto the old bottom plate 1 to a certain thickness. The thickness of the concrete 4 is determined in consideration of the cost of the concrete 4, the extent to which the concrete 4 reduces the volume inside the tank, the extent to which the concrete 4 increases the strength of the bottom plate, etc., and may be approximately 10 cm. In addition, if you lay a waterproof sheet on the top of the old bottom plate 1 before pouring the concrete 4, even if the bottom plate 1 becomes corroded and holes open, the waterproof sheet will prevent underground water from penetrating into the concrete 4. can be prevented.

Once the concrete 4 has hardened, a new bottom plate 5 is laid on top of it, as shown in Figure 2c. The peripheral edge of the new bottom plate 5 is joined to the side plate 2 by welding.
As a result, the bottom plate is old bottom plate 1 and concrete 4
It has a three-layer structure with a new bottom plate.

FIG. 3 shows an enlarged view of the part surrounded by the dotted line A in FIG. 2c. Since the new repair 5 is laid on top of the concrete 4, it does not come into contact with the ground and corrosion is prevented. Therefore, unlike the old bottom plate 1, there is no need to increase the plate thickness in anticipation of corrosion. Furthermore, since the old bottom plate 1 and concrete 4 also serve to support the liquid load, the new bottom plate 5 can be made thinner from this point of view as well.

In addition, in an oil tank, even if the lower surface of the bottom plate 1 is subjected to anti-corrosion treatment, the welding heat when joining the side plate 2 causes the lower surface of the welded part with the side plate 2 to become damaged as shown by reference numeral 6 in FIG. Prone to corrosion. Therefore, in the conventional method of replacing the bottom plate 1 with a new one, repairing this part is very time-consuming, but in the method according to the present invention, the old bottom plate 1 is left as is, so repair is easy.

As explained above, according to the present invention, when repairing the bottom plate of an oil tank, the old bottom plate is left as is, concrete is poured on top of it, a new bottom plate is laid on top of the concrete, and the side plate is replaced. Compared to the conventional method of repairing by replacing the bottom plate, this method has the advantage of making repairs much easier, such as eliminating the need to remove the old bottom plate. Additionally, since the new bottom plate is laid on concrete and does not come into contact with the ground, there is no need to increase the thickness of the bottom plate in anticipation of corrosion, as was the case in the past. Also, since the old bottom plate and concrete also serve to support the liquid load, the new bottom plate can be made thinner from this point of view as well.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the structure of a general oil tank, Fig. 2 is a sectional view showing an embodiment of the repair method according to the present invention, and Fig. 3 is a sectional view of the part surrounded by dotted line A in Fig. 2c. It is an enlarged view. 1... Old bottom plate, 2... Side plate, 3... Roof, 4
...Concrete, 5...New bottom plate.

Claims (1)

[Claims] 1. Repair the tank bottom plate by pouring concrete on the existing bottom plate inside the oil tank, laying a new bottom plate on top of this concrete, and joining the peripheral edge of this new bottom plate to the tank side plate. How to repair an oil tank.