JPS6152074B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a corrosion prevention device for the lowest part of a large tank for storing naphtha, crude oil, etc.

Since large tanks of this kind are installed in corrosive environments such as coastal areas, the current situation is that the lower part of the tank in particular comes into contact with the evaporated air of salt water and corrodes in a short period of time. Conventionally, in order to prevent this corrosion from occurring, a sealant is applied around the bottom of the tank, but this alone cannot provide sufficient corrosion protection as will be described later.

Generally, as shown in Fig. 4, in a large tank, the tank bottom plate (Annular plate) 1 is installed on an asphalt sand layer a, and the tank bottom plate 1 is welded with overlay 4.
The tank side plate 2 is installed by the tank side plate 2, and a concrete block layer b is laid under the extension of the tank side plate 2, which has the highest stress, and a ring-shaped building foundation 3 is placed around the tank separately from these foundations. Then, a structure c such as an anchor bolt is planted and installed on the structure foundation 3, and a support arm d is connected between the anchor bolt c and the tank side plate 2 with a bolt and nut e to prevent the sliding of the large tank. This is to prevent falls, etc. Furthermore, in order to prevent corrosion at the bottom of the tank, a sealing material f is packed between the periphery 1' of the tank bottom plate 1 and the asphalt sand layer a on the building foundation 3, and the sealing material f is packed between the bottom 2' of the tank side plate 2 and the periphery of the tank bottom plate 1' and applied the sealant 5.

However, in the case of large tanks of this type, there are times when the tank is filled with liquid such as naphtha or crude oil, and times when it is not filled at all, changes in the filling amount, uneven settling during long-term use, etc. As a result, significant behavior occurs between the tank bottom plate 1 and the building foundation 3, as shown from the solid line state T to the chain line state T' in Figure 1, and furthermore, due to seasonal temperature changes such as winter and summer, From the solid line position t in Figure 1 to the chain line position on the tank side plate, especially the tank bottom plate (annular plate) 1.
Thermal expansion and contraction as shown in t' occurs, which causes the asphalt sand layer a on the building foundation 3 in Figure 4 to
A crack occurs in the sealing material f between the sand layer a and the tank bottom plate periphery 1', and rainwater or salt water enters through the crack and corrodes the side plate lower part 2' from the bottom plate periphery 1' in a short period of time. Ta.

This invention was made to solve the above-mentioned difficulties, and will be explained below with reference to FIG. 1 showing an embodiment of this invention. It is characterized in that the band plate 6 is encapsulated and bonded with sufficient bending margin. More specifically, the sealing strip 6 is preferably made of a material with excellent weather resistance, flexibility, and flame retardancy, such as silicone rubber. After properly preparing the surface with a sander or the like, one end 6' of the silicone rubber band plate 6 is adhered to the lower outer peripheral surface 2' using the same silicone rubber as an adhesive, and a silicone rubber adhesive is applied appropriately to the periphery of the upper end. By overlaying and gluing and providing a drainage part 9, and further adhering the other end 6'' of the strip 6 to the ring-shaped building foundation 3, and providing the same drainage part 10 as described above on the end surface, The strip plate 6 covers and covers the lower part 2' of the tank side plate and the peripheral edge 1' of the tank bottom plate.

Furthermore, in this invention, as described above, the sealing strip 6 covering the tank side plate lower part 2' and the building foundation 3 is appropriately curved in a rounded shape, so that the strip 6 has sufficient bending margin. For example, the bending rate of the rounded curved portion of the silicon strip 6 from the tank bottom plate periphery 1' to the building foundation 3 is tripled, and the bending rate of the silicon strip 6 from the tank bottom plate periphery 1' to The length to the building foundation 3 is 40mm.
Then, the bending length is 40 x 3 = 120 mm, so the bending margin is 120 mm - 40 = 80 mm, so even if there is a step difference of 80 mm between the tank bottom plate 1 and the building foundation 3. The sealing band plate 6 is bent as shown in the hypothetical trajectory from the solid line section M to the chain line section M' in FIG. 1, and can sufficiently absorb the above-mentioned step difference. By providing the sealing band plate 6 with sufficient bending margin, a gap 7 will be generated in the covering area, but this will occur when the tank side plate 2 is used for a long period of time.
This is to make it easier to inspect the welded part 4 directly from the gap 7 when inspecting the welded part 4 between the tank bottom plate 1 and the upper end or lower end of the sealing strip 6. All you have to do is temporarily peel off the part.

FIG. 2 shows another embodiment of this invention,
The sealing strip 6 covering the tank side plate lower part 2' to the building foundation 3 is attached to the upper sealing strip 6.
a and a lower sealing strip 6b, and the lower sealing strip 6b covers and adheres from the tank bottom plate periphery 1' to the building foundation 3, and the strip 6b has sufficient bending margin. The tank side plate lower part 2' is covered by the upper sealing band plate 6a from the lower sealing band plate 6b, and the upper end 6'a of the band plate 6a is adhered to the tank side plate lower part 2'. The lower end portion 6''a is movably attached to the upper surface of the lower sealing band plate 6b in a downward slope.

According to this embodiment, when inspecting the welded portion 4, the inspection can be easily carried out by simply lifting the lower end 6''a of the upper sealing strip 6a from the upper surface of the lower sealing strip 6b. .

FIG. 3 shows still another embodiment of the present invention, in which the lower end 6''a of the upper sealing strip 6a shown in FIG. 2 is attached to the upper surface of the lower sealing strip 6b. In this embodiment, a dovetail groove 8a is further formed on the lower surface of the lower end portion 6''a, and a dovetail protrusion 8b is provided protrudingly on the upper surface of the sealing band plate 6b opposite thereto. By engaging these two parts with each other, rainwater can be prevented from entering through this overlapping part, and when inspecting the welded part 4, the engaged state of the two parts can be released as shown by the dashed line. This makes it possible to easily lift the strip 6a, thereby ensuring reliable inspection.

As described above, according to the present invention, a sealing band plate with excellent weather resistance and flexibility is wrapped and bonded between the tank side plate and the building foundation with sufficient bending margin, so that the tank side plate and the building foundation can be covered and bonded. Due to the behavior of tank side plates and bottom plates (annual plate) due to the weight of the contents, thermal expansion due to seasonal temperature changes, uneven settlement due to long-term use, etc. Even if there is a significant difference in level,
The sealing strip bends following this step, and no tensile stress is applied to the sealing strip. Therefore, the stress does not cause deterioration of physical properties, and it provides complete corrosion protection over a long period of time. The effect can be exerted.

In particular, in this invention, only the upper and lower ends of the sealing strip covering the tank side plate and the building foundation are adhered to the tank side plate and the building foundation, respectively, and the sealing strip covers the tank side plate and the tank bottom plate. There is a gap between the tank and the sealing strip, so if it is necessary to inspect the weld between the tank side plate and bottom plate after long-term use, the weld will be exposed through the gap. Therefore, repair and inspection are extremely easy.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a main part showing one embodiment of the present invention, FIGS. 2 and 3 are longitudinal cross-sectional views of main parts showing another embodiment of the invention, and FIG. 4 is a conventional example of this kind. FIG. DESCRIPTION OF SYMBOLS 1...tank bottom plate (annual plate), 1'...tank bottom plate periphery, 2...tank side plate, 2'...tank side plate periphery, 3...building foundation, 6...sealing strip, 6a...
Upper sealing strip, 6b...lower sealing strip, 7
...Gap portion, 8a, 8b...Locking portion.

Claims (1)

[Scope of Claims] 1. A sealing strip with excellent weather resistance and flexibility is provided with sufficient bending margin between the tank side plate and the building foundation for supporting the tank side plate from the side, and the tank side plate and the tank A corrosion prevention device for a large tank, characterized in that the bottom plate and the sealing band plate are encapsulated and bonded with a gap between them. 2. The sealing strip covering from the tank side plate to the building foundation consists of an upper sealing strip and a lower sealing strip, of which the lower sealing strip has sufficient flexibility from the tank bottom plate periphery to the building foundation. The upper sealing strip is encapsulated and bonded with sufficient flexibility, and one end of the upper sealing strip is bonded to the tank side plate.
A corrosion prevention device for a large tank according to claim 1, wherein the other end portion is attached to the upper surface of the lower sealing band plate. 3. Corrosion prevention for large tanks according to claim 2, wherein the upper sealing strip has one end adhered to the tank side plate and the other end removably attached to the lower sealing strip. Device.