JPS6325872B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Conventionally, a cylindrical tank is constructed by arranging the bottom plates (including the bottom end plates) while temporarily welding them, and after completing the entire arrangement, main welding is performed over the entire surface. This is due to the distortion of the bottom plate when the actual welding is performed from the beginning.
Since misalignment may occur and correcting the alignment etc. is a difficult task, the method is to perform temporary welding and then permanently weld the succeeding part.

However, this actual welding also has a diameter of 60m to 100m.
In some large tanks, there are hundreds of bottom plates, and the welding length is several kilometers, so welding cannot be done in a short time, and sometimes it takes more than two months. There are times when it rains, especially during the rainy season, when rainwater accumulates,
Also, if the joint is built near the coast, the sea breeze will cause rust on the joints, making it impossible to complete the welding process, so the rainwater and rust must be removed before welding. Almost no countermeasures were taken against it.

Also, even if rainwater and rust are removed from the surface of the joint, rainwater and rust between the backing metal provided at the bottom of the bottom plate joint and the bottom plate cannot be removed. It had some drawbacks, such as causing defects in the parts.

The present application was invented in view of these conventional drawbacks, and its purpose will be described.

The purpose of this application is to protect the welding surface by pasting the tape so that it does not sag across the adjacent bottom plates to prevent foreign matter from entering the welding surface, and then perform the main welding after the bottom plates are aligned. The purpose of the present invention is to provide a joint construction method for the bottom plate of a cylindrical tank.

Another purpose of this application is that since the final welding takes time, the bottom plate expands and contracts in response to temperature changes, so by protecting it with tape, the final welding is performed after the bottom plate is arranged. The purpose of the present invention is to provide a joint construction method for the bottom plate of a cylindrical tank.

A further object of the present application is to attach the tape at a distance from the welding surface so as not to leave foreign matter such as adhesive on the welding surface, and to prevent rust by shielding the welding surface from the outside air until the actual welding. To provide a joint method for bottom plates of a cylindrical tank, which prevents this from occurring and performs main welding after the bottom plates are arranged.

Another object of the present application is to completely eliminate the gap between the top surface of the bottom plate and the tape, and to coat the outer periphery and top surface of the tape so as to sufficiently cover the tape to prevent rainwater and foreign matter from entering the welding surface. The present invention provides a method for joining the bottom plate of a cylindrical tank, in which main welding is performed after the arrangement is completed.

In accordance with the above object, the present application has been invented, and after the bottom plates are aligned and temporarily welded at the joint between adjacent bottom plates of a cylindrical tank, a tape is applied to the welding surface 6 across the bottom plates. After that, apply a coating to sufficiently cover the tape, and apply both the tape and the coating to prevent adhesive or dust from adhering to the welding surface 6. The cylindrical type is designed to protect from rainwater and outside air, which can have a negative impact, and to protect from moisture and rust, which can cause welding defects, to maintain a more sound weld, and to perform main welding while peeling off the tape after the bottom plate has been aligned. To provide a joint method for tank bottom plates.

In the conventional construction method shown in Figure 5, the bottom plate A
If it rains after the arrangement and until the actual welding is performed, rainwater enters through the groove and collects in the gap between the bottom plate A and the foundation B, and this moisture C is a major cause of welding defects. Furthermore, since the groove surface is directly exposed to outside air such as sea breeze, rust is likely to occur on the groove surface, which is also one of the causes of adversely affecting the welded portion.

The present invention has a bottom plate 1 as shown in FIGS. 1 to 3.
In order to isolate the butt weld groove surface from moisture and outside air, the following construction method is used.

Immediately after arranging the bottom plate 1, the area near the welding line is cleaned and the first
The process of pasting the tape 2 as shown in Figures 2 to 3, and the coating of sufficient width to completely cover the tape 2 after pasting the tape 2 as shown in Figures 2 and 3. 3, and the joint portion 4 between the adjacent bottom plates 1 and the bottom plates 1 after the arrangement of the bottom plates 1 is completed.
The process consists of sequential welding while peeling off the tape.

Note that 5 and D indicate the backing money.

Further, at the part where the joint part 4 (welding line) intersects in a T-shape, as shown in FIG. 3, the tape 2 is pasted on the end part of the joint part 4 slightly longer to complete the seal.

Further, if the arrangement of the bottom plate 1 is interrupted, the base, the backing metal 5 and the ends of the bottom plate 1 are sealed with tape 2 and coating 3 so that they do not come into contact with the welding surface.

To explain the purpose of using both tape and coating to protect the welding surface in this application, in the case of tape alone, the size of one bottom plate is 15 m x 3 m, so a long distance of 15 m can be covered without wrinkles. It is impossible to adhere the coating to the surface of the weld groove, and the wrinkles create gaps that allow rainwater and dust to enter the weld groove surface.If only coating is used, the disadvantage is that it also adheres to the weld groove surface. Therefore, by applying the tape tautly across the adjacent bottom plate and the bottom plate without any slack, and applying a coating wide enough to completely cover the tape from the top, the coating will be applied to the weld groove surface. The coating completely covers the creases created when the tape is applied and completely isolates it from the outside.

As described above, in the construction of a bottom plate joint for a cylindrical tank, the tape 2 is pasted across the adjacent bottom plates 1 each time the bottom plates 1 are sequentially arranged while performing temporary welding, and then the tape is applied sufficiently. Coating 3 is applied from above so as to cover the joints 4 of the adjacent bottom plates 1 and the bottom plates 1 from rainwater and the outside air. After the entire arrangement of the bottom plates 1 is completed, the joints 4 are coated while peeling off the tape 2. Since welding is carried out sequentially, it is possible to almost completely prevent rainwater and outside air from entering the weld groove during welding of the bottom plate butt joint of a cylindrical tank, thereby ensuring a sound weld. can be obtained.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the tape pasted on the bottom plate joint in the present application, Figure 2 is a perspective view of the coating after the tape has been pasted, and Figure 3 is the tape pasted on the T-shaped cross section of the bottom plate joint. FIG. 4 is a sectional view of the joint portion, and FIG. 5 is a sectional view of the conventional construction method.

Claims (1)

[Claims] 1. In the construction of the bottom plate joint of a cylindrical tank, after temporarily welding the bottom plates 1 and affixing the tape 2 across the adjacent bottom plates 1 and 1 each time the bottom plates 1 are arranged one after another, the tape 2 is attached to the upper part so as to sufficiently cover the tape. A coating 3 is applied to insulate the adjacent bottom plates 1 and joints 4 of the bottom plates 1 from rainwater and outside air, and after the entire arrangement of the bottom plates 1 is completed, the joint surfaces 4 are successively welded while peeling off the tape 2. A joint construction method for the bottom plate of a cylindrical tank.