JPH0125865B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of constructing a bottom corner of a low-temperature flat-bottom cylindrical storage tank in which a T-beam is incorporated into the bottom corner.

[Conventional technology]

FIG. 2 is a perspective view showing a conventional method of constructing a flat-bottomed cylindrical storage tank in which sections are provided at the bottom corners, as disclosed in, for example, Japanese Patent Application Laid-Open No. 56-119079 (filed by Kawasaki Heavy Industries, Ltd.). In the figure, 1 is a foundation (bottom cold insulator) constructed at the construction site of a flat-bottomed cylindrical storage tank, and 2 is a pedestal placed at appropriate intervals on the foundation 1.

The conventional construction method is to first place the required number of corner sections 3 on the frame 2 and assemble them into a ring shape.
are sequentially welded to form a ring-shaped section A, and the welded portion of the section A is inspected. Next, the annular plate 4 is arranged along the inner edge of the section A, and the sections A and the annular plate 4 and each annular plate are successively welded and inspected to form the section 3. A storage tank angle body B with an integrated annular plate 4 is obtained. This storage tank corner body B is lowered and installed onto the foundation 1 from the pedestal 2, using the central part of the foundation 1 as a work space. This method of descent includes lowering with a jack, setting up a temporary suspension pedestal and removing the pedestal while suspending it, making the pedestal vertically expandable and lowering it one by one, or removing the pedestal. In the case of a shell storage tank, a bracket is temporarily installed on the side plate of the outer tank, and the tank is lowered while being suspended from this bracket.

[Problem that the invention seeks to solve]

The conventional construction method is to weld and inspect the ring-shaped corner body on the frame 2 as described above, and then weld the annular plate 4 to the ring-shaped section A and inspect it. If the frame 2 is placed so that the joint position is removed in the radial direction, high-quality welding can be performed without difficulty and the welded part can be inspected accurately, but in the circumferential direction, the second It is unavoidable that the pedestal 2 and the joint intersect, as shown by arrow C in the figure. Therefore, the intersection of the pedestal 2 and the joint must be inspected after completing the welding inspection of the joint other than this intersection. It is necessary to perform welding and inspection by shifting the position of the pedestal 2, which not only requires a great deal of labor, but also risks damaging the foundation (bottom cold insulating material) 1 when the pedestal 2 is moved. In the case of a low-temperature double-shell storage tank, there is also the problem that it is very difficult to lower the storage tank corner body B formed on the pedestal 2 onto the foundation 1 with high accuracy so that the center line of the storage tank does not shift.

[Means for solving problems]

In the construction method of the low-temperature double-shell storage tank of this invention, the corner T-shaped steel and the annual plate are welded in the circumferential direction for each block in advance at a factory or storage tank construction site, and a radiation inspection of this welded part is completed. The joints of each corner block made of the corner T-shaped steel and the annular plate are placed on the notches provided at appropriate intervals in the bottom cold insulating material, and the corner T-shaped joints of each corner block are The joints between the shape steels, between the annular plates, and between the corner T-shape steel and the annular plate are welded from the front and back sides, and after radiological inspection of these welded joints, cold insulation is applied to the notch of the bottom cold insulator. This method involves supplementing the material, then assembling and welding the side and bottom plates using normal construction methods.

[Effect]

As described above, the joint part of each corner block made of the corner T-shaped steel and the annular plate, which have been welded and inspected in advance, is placed on the notch provided in the cold insulation material, and In this step, the joint portion is welded from the front and back sides, and the welded portion is also inspected by radiation, so that welding and inspection are reliable. Furthermore, positioning is facilitated by placing each corner block directly on the bottom cold insulating material.

〔Example〕

FIGS. 1A, 1B, and 1C are explanatory diagrams showing the construction order of an embodiment of the present invention. In the figure, 5 and 5A are corner blocks in which the corner T-shaped steel 6 and the annular plate 4 are welded in advance and inspection has been completed, and 7 is notches provided at appropriate intervals in the bottom cold insulating material 1.

First, as shown in Figure a, the corner blocks 5 and 5A are
The corner blocks 5 and 5A are placed on the bottom cold insulator 1 so that the joint parts 8 to 8B are located in the notch 7 of the bottom cold insulator 1, thereby forming a ring-shaped bottom corner body. Next, using the notch 7 of the bottom cold insulating material 1 as a working space, as shown in FIG.
After welding the joint 8 between the corner T-shaped steel 6, the joint 8A between the corner T-shaped steel 6 and the annular plate 4, and the joint 8B between the corner T-shaped steel 6 and the annular plate 4 from the front and back, Perform inspections and repairs.

After this inspection is completed, the notch 7 of the bottom cold insulating material 1 is filled with cold insulating material 9 as shown in FIG. c. Thereafter, the side plates and bottom plate are assembled and welded using normal construction methods to complete the low temperature double shell flat bottom cylindrical storage tank.

Therefore, the ring-shaped bottom corner body can be easily and reliably welded and inspected by using the notch 7 of the bottom cold insulating material 1.

〔Effect of the invention〕

As described above, this invention performs welding and inspection of the connecting portion of the bottom corner body on the bottom cold insulating material, eliminating the need for a frame for welding and inspection as in the past. When carrying out welding and inspection work, it is possible to eliminate dangerous work such as welding joints that intersect with the pedestal, moving the pedestal for inspection, and removing the pedestal after work is completed, resulting in safe construction. Welding and inspection can be performed reliably using the method.

[Brief explanation of drawings]

FIGS. 1a, b, and c are explanatory diagrams showing the construction order of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of a conventional method. 1... Bottom cold insulation material, 4... Anyura plate,
5, 5... Corner block, 6... Corner T-shaped steel, 7... Notch of bottom cold insulator, 8, 8A, 8B
...Joint part, 9...Cold insulation material.

Claims (1)

[Claims] 1 Joints for each corner block consisting of a corner T-shaped steel and annular plate, in which the corner T-shaped steel and annular plate are welded in the circumferential direction for each block in advance, and radiological inspection of the welded parts has been completed. Place the parts on the notches provided at appropriate intervals in the bottom cold insulator, and place the parts between the corner T-shaped steels of each corner block, between the annular plates, and between the corner T-shaped steel and the annular plate. After welding the joint from the front and back sides and performing a radiological inspection of the welded joint, the notch provided in the bottom cold insulation material is filled with cold insulation material, and then the side and bottom plates are assembled using the usual construction method. A construction method for a low-temperature double-shell storage tank characterized by welding.