JPH0152547B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for assembling a double-shelled spherical tank for storing low temperature liquefied gas.

A general method of assembling a conventional double-shelled spherical tank will be explained with reference to the completed diagram in FIG.

In other words, in the conventional assembly method, the outer tank support 1 is erected on the foundation 6, the equatorial part of the outer tank 2 and the lower temperate zone of the outer tank are built on top of it, then the inner tank 3 is assembled, and the outer tank The inner tank 3 was suspended at the bottom of the outer surface of the inner tank via a plurality of suspension rods 5 or wire ropes engaged with brackets 4 protruding from the inner wall.

In this conventional structure, the inner tank 3 is the outer tank 2.
Because of the structure of suspending and holding the tank, it was necessary to assemble the outer tank 2, which serves as the frame for the inner tank 3, in advance before assembling the inner tank 3. In that case, when assembling the inner tank 3, the distance between it and the outer tank 2 is 600mm to 700mm.
Because the space was so narrow, it was difficult for workers to get into the space and carry out work. For pressure vessels that are particularly dangerous, such as spherical tanks, it is a major requirement to thoroughly inspect both the interior and exterior of the members after welding to increase joint efficiency and ensure the safety of the vessel. Therefore, the narrow working space for welding, inspection, etc. has been a major problem not only in terms of assembly work efficiency but also in terms of quality control of the container itself.

In addition, in the case of the conventional method, the outer tank 2 needs to function as a frame to hold the inner tank 3, so the outer tank 2 must have a strong structure to maintain its rigidity, and the required plate thickness also increases. The size of the project required sufficient welding work and inspection.

In addition, in order to secure the work space mentioned above, 600mm
It is necessary to construct the tank at a distance of about 700 mm from the inner tank 3, and as a result, an outer tank with a diameter significantly larger than the actual capacity of the inner tank 3 has to be prepared, which has the disadvantage that the weight of the components becomes enormous. Ta. Furthermore, this conventional method requires a complicated support structure to accommodate the thermal expansion and contraction of internal components such as the inner tank 3 and suspension rods 5, as well as vibrational movements caused by earthquakes.
There was also a drawback that the number of suspension rods 5 was large.

In addition, a reinforcing ring 7 is also required for the outer tank 2 that receives the load of the inner tank 3, and it is also necessary to provide a large number of reinforcing ribs to transmit the load from the outer tank 2 to the struts 1, making the support structure complicated. It had become

In addition, the inner tank 3 is simply a rod 5 extending from the outer tank wall.
Because the structure is suspended vertically by means such as, and does not have a horizontal restraint function, there is a high risk that the inner tank 3 will shake significantly in the event of an earthquake, making the entire tank unstable. There were also serious flaws.

The present invention was developed in view of the above circumstances, and eliminates the drawbacks of conventional construction methods, provides high assembly accuracy and excellent assembly workability, and also eliminates the instability of the behavior of the inner tank during earthquakes, etc., making it stable. This provides a construction method for constructing a spherical tank with a double shell structure.

The gist of this is that an outer tank support is fixed to the base plate concentrically outside the inner tank support, and a cylindrical upper column that supports the outer tank equatorial plate is installed on the outside of the outer tank support. is inserted into the support column in advance so that it can move up and down, and the composite support structure is erected on the foundation.The inner tank is first assembled and welded, and then all inspections such as welding inspection and pressure resistance inspection are completed. After that, lift and fix the upper column that had been lowered to the base of the column to the specified position, and then
The penetrating part of the inner tank column is cut out in advance, and the outer tank column equatorial plate, which is divided into upper and lower parts with the column as the boundary, is inserted and joined to the top of the column, and the outer tank column is assembled in the same manner. A method for assembling a spherical tank with a double shell structure, in which the outer tank equatorial plate is assembled between the outer tank equatorial plates, the outer tank equatorial plate is assembled between the supports, and the upper and lower temperate zone plates and the polar plates are assembled. It is.

Next, details of embodiments of the present invention will be described in accordance with the drawings.

FIG. 2 is a partially cutaway view of a completed double-shelled spherical tank assembled using the construction method of the present invention.

The assembly procedure using the method of the present invention is shown in Figures 2 and 3.
This will be explained with reference to the drawings that follow.

Figure 3 is a diagram showing the situation when assembling the pillars.
An outer tank support 32 is placed concentrically on the outside of the inner tank support 31.
is fixed to a common base plate 33, and a cylindrical upper column 36 that supports the outer tank equatorial plates 34 and 35 is fitted on the support column in advance so that it can move up and down. A composite support column 39 made up of three cylindrical bodies is erected on a foundation 39, and the inner tank 38 is first assembled entirely.

It should be noted that if the composite strut 39 is manufactured at a factory equipped with processing equipment, it is possible to manufacture the composite support 39 with higher precision.
An upper gusset plate 41 and a lower gusset plate 42 are provided at the upper and lower parts of the column for attaching bracing rods 40, which are reinforcing members.
Fix it in advance.

The assembly procedure for the inner tank 38 is the same as that for conventional single-shell spherical tanks.First, the equatorial plate, upper and lower temperate plates, and upper and lower polar plates are temporarily assembled, and the dimensions of each part and the misalignment of the joints are measured. After confirming that everything is within tolerance, weld the inside and outside surfaces, and then complete various welding inspections and pressure tests.

At this stage of assembling the inner tank, the outer tank plate is not attached at all, so various operations such as welding and inspection can be carried out over the entire inner tank from both the inside and outside, resulting in excellent workability.

Next, prepare to assemble the outer tank.

FIG. 4 is a diagram showing a state in which the upper column 36, which receives the equatorial plates 34, 35 of the support portions of the outer tank, is lifted up to a predetermined height and fixed.

That is, in FIG. 3, the upper column 36 is lowered to the lower part of the outer tank support 32 and lifted up to a predetermined height, and the lower end of the column is connected to the outer tank support via a cone shell 43 formed into a conical shape. 3
FIG. 4 shows the state in which it is joined to the upper end portion of No. 2. The cone shell 43 is divided into two parts in advance and then joined to the support pillars.

A guide groove 44 is provided in the axial direction on the side of the upper column 36, into which the upper gusset plate 41 is fitted, providing a mechanism for accurately guiding the column to a predetermined position. .

Assemble all the pillars in the same manner.

Next, assemble the equatorial plate for the outer tank support.

FIGS. 5 and 6 show the working conditions for attaching the outer tank support equatorial plates 35 and 34.

The outer tank support equatorial plate has a notch in the penetrating part of the inner tank support 31, and two holes in the upper and lower parts around the support.
divided into outer tank support upper equatorial plates 35,
It is composed of an equatorial plate 34 on the lower side of the outer tank support.

First, as shown in FIG. 5, the lower equatorial plate 34 is
Lift up the upper column 3 from the inside of the column group.
6 to the upper edge opening. Next, as shown in FIG. 6, the upper equatorial plate 35 is suspended from above the outer side of the support column 39, and the upper column 36 is inserted so that the top part is sandwiched between the two equatorial plate materials 34 and 35. Construct the equatorial plate of the outer tank support. In the same way, after forming the equatorial plates for each outer tank support, the equatorial plates 45 between each support are sequentially suspended, inspected for dimensions over the entire circumference, and then welded to form an integral outer tank equatorial part. To construct. If the equatorial plate 45 between the supports is made of two or more materials, several materials may be joined together on the ground in advance.

Next, the upper temperate zone plate 46 and the lower temperate zone plate 47 of the outer tank are assembled, and then the outer tank upper polar plate 51 is assembled.
In this construction method, the outer tank lower electrode plate 49 is assembled to complete the entire inner and outer tanks. (Fig. 2) According to this construction method, the outer tank 48 and the inner tank 38 are supported separately by the outer tank support 32 and the inner tank support 31, respectively.
Because the structure is such that they are not in direct contact with each other,
Stress due to thermal expansion and thermal contraction of the inner tank 38 is applied to the outer tank 48.
is rarely communicated directly. In other words, the inner and outer tank supports 3 are erected upward from a common base plate 33.
1 and 32 have a free end structure, so that even if a bending moment is applied to the struts when the inner tank 38 thermally expands or contracts, the inner tank struts 31 are only displaced independently and the outer tank struts are 32 is not displaced. In other words, the deformation resistance of the struts is small and driving is safe.

Moreover, since the outer tank part is not connected immediately to the inner tank support part, there is an advantage that the amount of cold heat transferred from the inner tank to the outer tank is small.

Furthermore, according to this structure, since the inner tank 38 is directly supported by strong columns, the swinging of the inner tank 38 during an earthquake can be reliably restrained, thereby improving safety.

Furthermore, since the outer tank 48 does not need to have the function of rigidly suspending the inner tank 38 and merely serves as an exterior material that supports the heat insulating layer 50, the requirements for strength can be considerably reduced, and therefore the exterior The material is a relatively thin sheet of ordinary steel, which reduces the weight of the components. Furthermore, the composite strut 39 produced by this method can be pre-assembled in a factory in an integrated and compact manner, which has the advantage of increasing processing accuracy and reducing the cost of transporting materials from the factory to the construction site.

As is clear from the above description, according to the present invention, the work of assembling a double shell spherical tank is simplified, and the stress acting on the support material is the most severe during filling with low-temperature liquefied gas, during release, or Even during an earthquake, the applied stress can be alleviated, and the number of parts used in the outer tank can be reduced, which can greatly contribute to lower construction costs and safer operations.

[Brief explanation of drawings]

FIG. 1 is a partially cut away view of a completed double-shelled spherical tank constructed using a conventional assembly method. FIG. 2 is a partially cut away completed view of a double shell spherical tank constructed by the assembly method of the present invention. FIGS. 3 to 6 are diagrams showing examples of the construction method of the present invention. FIG. 3 is a perspective view showing the state when the struts are assembled, and FIG. 4 is a perspective view showing the upper column 36, which receives the equatorial plates 34, 35 of the outer tank support section, lifted to a predetermined height and fixed. Yes, Figure 5 shows the lower equatorial plate 3 of the outer tank support.
4 is a perspective view showing a situation in which the upper equatorial plate 35 of the outer tank support section is assembled into the upper edge opening of the upper column 36, and FIG. FIG. 1...Outer tank support, 2...Outer tank, 3...Inner tank, 4
... Bracket, 5 ... Suspension rod, 6 ... Foundation, 7 ... Reinforcement ring, 31 ... Support for inner tank, 32 ...
...Strut for outer tank, 33...Base plate, 34...
...Equatorial plate on the lower side of the outer tank support, 35... Upper equatorial plate on the outer tank support, 36... Upper column, 37... Foundation, 38... Inner tank, 39... Composite support, 40...
Bracing rod, 41... Upper gusset plate, 42... Lower gusset plate, 43...
Cone shell, 44...Guide groove, 45...Equatorial plate between columns, 46...Outer tank upper temperate zone plate, 47...Outer tank lower temperate zone plate, 48...Outer tank, 49...Outer tank lower polar plate, 50...Heat insulation layer, 51...Outer tank upper electrode plate.

Claims (1)

[Claims] 1. An outer tank support is fixed to the same base plate concentrically on the outside of the inner tank support, and a cylindrical upper column that supports the outer tank equatorial plate concentrically is installed in advance on the outside of the outer tank support. The composite strut is inserted into the above-mentioned strut so that it can move up and down, and the composite strut is erected on the foundation. First, all the inner tanks are assembled and welded, and then a welding inspection and a pressure resistance test are performed, and then the composite strut is installed at the base of the strut. After hoisting and fixing the lowered upper column to a predetermined position, cut out the penetrating part of the inner tank column in advance, and cut out two holes in the upper and lower parts with the column as the boundary.
The outer tank support equatorial plate that has been separated is inserted into the top of the upper column and fixed together, and then the respective outer tank support equatorial plates are assembled in the same manner. Next, the outer tank equatorial plate between the supports is assembled. A method for assembling a double-shelled spherical tank, characterized by assembling the outer tank to form an integral outer tank equatorial section, and then assembling upper and lower outer tank temperate zone plates and outer tank polar plates.