JP3516215B2 - Construction method of tank bottom plate in double shell storage tank and its lifting device - Google Patents

Description

Detailed Description of the Invention

[0001]

This invention relates to liquefied natural gas (LN
When building a double shell storage tank for storing G) or low temperature liquid, etc., after welding the inner tank bottom plate of the storage tank on the pedestal, remove the pedestal and lower the bottom plate to install it on the bottom cold insulation layer. The present invention relates to a method for constructing a bottom plate of a storage tank and a lifting device used for the method.

[0002]

2. Description of the Related Art A conventional construction method for a bottom plate of a double-shell storage tank is shown in a sectional explanatory view of FIG. The outer tank bottom plate 102 is laid on the storage tank foundation to form the outer tank 101 composed of the outer tank side plate and the outer tank roof. Inside the outer tank 101, an inner tank 105 having a sealed structure for storing liquefied natural gas (LNG) and the like is constructed via a cold insulation layer and a cold insulation space. The bottom cold insulation layer 103 is applied on the outer tank bottom plate 102 inside the outer tank 101, and the outer ring annular inner tank annular plate, inner tank side plate, and inner tank roof are installed on the upper portion thereof.

The inner tank bottom plate 106 is constructed on the frame 104 shown by the broken line in FIG. This mount 104 is used for the outer tank bottom plate 10.
2 is provided directly on the outer tank bottom plate 102 or on the bottom cold insulation layer 103 constructed at appropriate intervals.
The inner tank bottom plate 106 is arranged on the frame 104. Since the inner tank bottom plate 106 places importance on air-tightness and liquid-tightness, a butt welded joint is generally adopted, and welding is performed from both upper and lower surfaces.
Inspections are also performed from the top and bottom. In addition, the bottom cold insulation layer 1
At the joint between the outer peripheral edge of the inner tank bottom plate 106 that has descended above 03 and the outer peripheral ring-shaped annular plate, a one-side butt-welded joint with a backing metal is adopted, and the joint is made only by welding from the upper surface.

The inner tank bottom plate 106 is formed by arranging rectangular flat plates or fan-shaped flat plates on the base 104 to assemble the whole into a circular flat plate, and welding is performed from both upper and lower surfaces to integrate them, and the inner tank bottom plate 106 is wired from above. After being slightly lifted at 122 to remove the lower gantry 104, it is lowered and placed on the bottom cold insulation layer 103. Reference numeral 121 in the figure denotes a reinforcing member provided to suspend the inner tank bottom plate 106. The reinforcing member 121 is the inner tank bottom plate 1
The wires 06 are arranged in an average grid shape or a ring shape so as not to bend when the wires 122 are hung by the wires 122 and to prevent the local concentrated load from being biased on each wire 122. 122 is the inner tank bottom plate 10
6 is a suspending wire for suspending 6 and 123 is a suspending support portion for supporting the wire 122 above. This suspension support 123
Shows a case where a bracket or the like is provided on the inner peripheral surface of the side plate in the upper part of the inner tank 105, but the hanging position is
Depending on the construction period of the inner and outer tanks, the upper side plate or roof of either the inner or outer tank is selected.

Another conventional construction method for lowering the inner tank bottom plate on the bottom cold insulation layer is a construction method using a jack or the like although not shown. In this construction method, a jack and a board stand etc. are placed at appropriate places on the bottom cold insulation layer, and they are assembled and welded on the stand where the inner tank bottom plate is arranged, and integrated.
This is a method in which the inner tank bottom plate is slightly raised by a jack, and the inner tank bottom plate is gradually lowered while removing the blocks that make up the rack one by one. In this method, a worker enters the lower part of the bottom plate of the inner tank and disassembles and removes the stand and jack of the plank.

[0006]

According to the conventional construction method shown in FIG. 6, the wire 122 is hung on the suspension supporting portion 123 attached to the upper part of the side plate or a high place such as the roof, and is deformed by being heavy and bending. In order to suspend the inner flat plate 106, which is a thin flat plate that is easy to perform, there were the following problems. Wide thin inner tank bottom plate 106
The wire 1 so that it is not deformed by bending.
In order to suspend the wire 22 evenly so that an unbalanced load is not applied to 22, a large number of reinforcing members 121 must be evenly mounted on the inner tank bottom plate 106 in a lattice shape or a ring shape. Many temporary materials and temporary jigs were required, and the work of attaching and removing them was complicated.
Further, there are many repair processes and inspections of the marks of the jig to which the reinforcing member 121 is attached, which requires a lot of man-hours and labor. In addition, it was difficult to operate and drive a large number of long wires 122 hung from a high position on average to keep the inner tank bottom plate horizontal and move up and down. Moreover, since the suspension support portion 123 is provided at a high position,
Dangerous high-place work occurred in its installation. Furthermore, since the work of suspending the inner tank bottom plate 106 by attaching the suspending support portion 123 cannot be performed unless the side plate or the roof for mounting the suspending support part 123 is formed, there is a restriction in the process of raising and lowering the inner tank bottom plate 106. As a result, there is a problem that many steps are required for the whole process.

Further, the conventional construction method using a jack or the like has the following problems because the work is performed under the inner tank bottom plate. Workers enter the narrow and dark space below the inner tank bottom plate, support the inner tank bottom plate with a jack, manually dismantle and remove the boards of the rack one by one, and lower the inner tank bottom plate with the jack. The workability was very poor and dangerous. In addition, since the bottom plate of the inner tank is likely to tilt, it is difficult to lower the inner tank so as not to deform it, and the work efficiency is not good.

The present invention has been made in view of the above-mentioned problems, and it is possible to safely and efficiently and economically lower and place the inner tank bottom plate assembled and welded on the pedestal on the bottom cold insulation layer. (EN) A method for constructing a bottom plate in a double-shell storage tank and a lifting device for the same.

[0009]

According to a first aspect of the present invention, there is provided a method for raising and lowering a bottom plate of an inner shell of a double shell storage tank, in which welding of the bottom plate of the inner shell is carried out on a pedestal arranged on a bottom cold insulation layer of the double shell storage tank. In the construction method of the double shell storage tank inner tank bottom plate which is carried out, the inner tank bottom plate is lowered by the lifting device and placed on the bottom cold insulation layer, a through hole is provided in the inner tank bottom plate on the frame , in the through-hole
The post that serves as a support member for the bottom plate of the inner tank penetrates through and is removably mounted on the bottom cold insulation layer , and the post is engaged to engage the inside.
The inner tank bottom plate is lowered by an elevator installed above the tank bottom plate , the inner tank bottom plate is placed on the bottom cold insulation layer, and then the lifting device including the post is removed, and then the through hole is closed. .

Further, in the double shell storage tank of the invention according to claim 2
The construction method of the tank bottom plate is larger than the through-hole to hold the above-mentioned post on the bottom cold insulation layer just below the through-hole.
Install a base plate of dimensions and engage the above post
The bottom plate of the inner tank is lowered by an elevator that moves to the bottom cold insulation layer.
After placing, after removing the lifting device including the post,
Insert the insertion plate into the through hole located on the upper surface of the base plate.
Then, use the above base plate for the backing metal for welding , and
The outer peripheral edge of the insert plate and the inner tank bottom plate are butt-welded and closed.

The lifting device of the invention according to claim 3 is
Bearing in tank bottom plate through the through hole of the inner tub bottom plate of the double-shelled reservoir
As a member, it can be attached and removed freely on the bottom cold insulation layer
And Posuto provided with upright, and elevator installed in the inner tank bottom plate top so as to lower the inner tank bottom plate, the claim by the engaging portion provided on the Posuto to engage said with the elevator Posuto The bottom plate of the double shell storage tank according to 1 or 2 is applied.
The lifting device used in the construction method is formed.

[0012]

The method for constructing the inner shell bottom plate of the double shell storage tank according to the present invention is such that the inner shell bottom plate is arranged and assembled on a frame and welded, and then an appropriate number of lifting devices are installed at appropriate places on the inner shell bottom plate. ,
Lower the inner tank bottom plate onto the bottom cold insulation layer .

Further, the lifting device descends the bottom of the inner tank by penetrating through the through-holes formed at a plurality of positions on the bottom of the inner tank at a predetermined interval so as to be attached and detached on the bottom cool layer. An elevator installed above the bottom plate of the inner tank , and an engaging portion provided on the post so as to engage the elevator with the post, so that the load of the inner tank bottom plate is applied through the engaging portion. while supporting Posuto, by driving the elevator, the inner tank bottom plate can be raised downward. Also, each post can be easily attached, removed and removed from the top of the inner tank bottom plate through each through hole. Using this elevating device, the bottom plate of the inner tank is supported, and the bottom plate of the inner tank is removed by slightly raising it from the rack, and then the bottom plate of the inner tank is gradually lowered and placed on the bottom cold insulation layer. The post of the lifting device is removed from the upper part of the through hole. Further, the through hole of the inner tank bottom plate is closed from the upper part.

On the bottom cold insulation layer immediately below the through hole,
Since the installed base plate receives a load applied to each post over a wide area, an unreasonable local load is not applied to the bottom cold insulation layer, and the load of the inner tank bottom plate supported by each post is evenly distributed. Then, after removing the lifting device including a Posuto, through holes provided in the inner tank bottom plate, the through hole
Larger than the through hole for inserting the insertion plate and holding it immediately below it, that is , at the bottom of each post of the lifting device.
Use the base plate of the dimensions on the back losses for the welding, above
The outer peripheral edge of the insertion plate and the bottom plate of the inner tank are butt-closed from the upper surface by one-side butt full penetration welding.

[0015]

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional explanatory view showing a construction method of a bottom plate of a double-shell storage tank according to the present invention, and FIG. 2 is an enlarged cross-sectional explanatory view showing a lifting device used in the construction method of FIG. Is. Figure 1
As shown in (1), the outer tank 1 is provided on the storage tank foundation, and the inner tank 5 having a sealed structure for storing liquefied natural gas (LNG) and the like is built therein. The inner tank 5 covers the bottom cold insulation layer 3 on the outer tank bottom plate 2, the outer ring ring-shaped inner tank annular plate and the circular inner plate inner tank bottom plate, the cylindrical inner tank side plate, and the inner tank side plate upper portion. It consists of an inner tank roof. The inner tank bottom plate 6 is
Similar to the construction method of the conventional example described above, the construction is performed on the gantry 4 arranged in an appropriate number above the bottom cold insulation layer 3.

As shown in FIG. 1 and FIG. 2, the construction method of the inner tank bottom plate 6 according to the present invention has an appropriate position of the inner tank bottom plate 6, that is, an interval such that the inner tank bottom plate 6 is not bent by its own load. A plurality of through holes 7 are provided in advance, and a post 9 that penetrates through the through holes 7 and serves as a support member for the inner tank bottom plate 6 is detachably attached to the bottom cold insulation layer 3 and engages with the post 9 to form an inner tank. A lifting device 11 for lifting the bottom plate 6 is attached. This lifting device 11
Is a post 9 standing upright on a base plate 8 provided on the bottom cold insulation layer 3 immediately below the through-hole 7, an elevator 10 installed on the inner tank bottom plate 6 above it, and the elevator 10 and the post 9. It is formed from the engaging portion 14 provided on the post 9 so as to be engaged. The elevator 10 does not necessarily have to be installed on the inner tank bottom plate 6, and will be described later with reference to FIG.
The installation method as shown in (B) may be used.

An embodiment of the construction method and lifting device 11 according to the present invention will be described in more detail with reference to FIG. In the figure, 2 is an outer tank bottom plate, 3 is a bottom heat insulation layer, and 4 is a mount for assembling the inner tank bottom plate 6. A predetermined number of mounts 4 are arranged on the bottom cold insulation layer 3, and an inner tank bottom plate 6 is arranged on this mount 4 to perform welding and inspection from both upper and lower sides. The post 9 of the lifting device 11 is penetrated through the through hole 7 provided in the inner tank bottom plate 6, and the lower end of the post 9 is installed so as to be held on each corresponding base plate 8. Base plate 8 provided directly under the through hole 7
Is a backing metal 16 for welding when the through hole 7 is closed, so that the through hole 7 is formed from a flat plate having a size slightly larger than that of the through hole 7 so that the through hole 7 is closed from the bottom, and the upper surface of the bottom cold insulating layer 3 is formed. It is buried and formed so as to be even with the upper surface. In addition, the base plate 8 is formed in a wide and large size to dispersively support the load applied to each post 9 and to avoid the local load applied to the corresponding bottom cold insulation layer 3 as much as possible, and the bottom cold insulation layer 3 may be depressed or damaged. Although it is not shown in the drawings when the emphasis is placed on the backing for welding, the backing metal 16 formed by a ring-shaped flat plate having an opening inside may be used.

The elevator 10A of the elevator 11 shown in FIG.
Shows an example formed by the guide roller 12, the wire 13, and the winder 15. A winder 15 is attached on the inner tank bottom plate 6, a guide roller 12 is fixed to the engaging portion 14 at the upper end of the post 9 and one end of the wire 13 is fixed to the upper part of the inner tank bottom plate 6.
Is engaged with the guide roller 12 of the engaging portion 14 and wound around the winder 15. The winder 15 is operated to support the load of the inner tank bottom plate 6 by the base plate 8 and the post 9 to raise and lower the inner tank bottom plate 6.

First, after the assembly welding and inspection of the inner tank bottom plate 6 are completed, the winder 15 is operated to wind up the wire 13 to slightly raise the inner tank bottom plate 6 from the pedestal 4 and remove the lower pedestal 4. . Next, the winder 15 is operated and the wire 13 is gradually returned to lower the entire wire to an average. Thus, the elevator 10A using the winder 15 for winding the wire 13
Alternatively, a winding machine 15 may be installed so as to wind up a plurality of wires 13 in a lump to perform centralized operation and management. After the inner tank bottom plate 6 is placed on the bottom cold insulating layer 3, the post 9 and the elevator 10A are removed from the upper portion of the inner tank bottom plate 6 to close the through hole 7.

FIG. 3 is a partially cutaway cross sectional view showing a second embodiment of the lifting device according to the present invention. The lifting device 11 is provided with a parallel gear rack 18 on an engaging portion 14 of a post 9 standing on the base plate 8, a circular gear pinion 19 that engages with the rack 18, and a drive for rotating the pinion 19. An elevator 10B including the device 20 is provided on the upper portion of the inner tank bottom plate 6. The elevating device 10B including the rack 18, the pinion 19 and the drive device 20 changes the rotational movement into parallel movement by meshing the gears, and controls and raises and lowers the inner tank bottom plate 6 horizontally. You can

FIGS. 4 (A) and 4 (B) are sectional explanatory views showing a third embodiment of the lifting device according to the present invention with a part omitted. The elevator device 11 shown in FIG. 4 (A) is provided with an elevator 10C composed of a jack 21 so as to be positioned above the inner tank bottom plate 6 on the post 9 standing on the base plate 8 and the engagement of the jack 21. A suspension arm 22 that engages with the portion 14 is provided on the upper portion of the inner tank bottom plate 6. In this case, since the jack 21 is provided on the inner tank bottom plate 6, the operation and management can be easily performed from above, and the size of the through hole 7 can be reduced. The lifting device 11 shown in FIG. 4 (B) is provided with the jack 2 directly on the base plate 8.
The elevator 10D made of 3 assembled and provided with providing Posuto 9 in the upper, the support arm 24 that engages with the engaging portion 14 of the Posuto 9 on top of the inner tank bottom plate 6 changes
It is a form example . In this case, since the jack 23 is provided at the lowermost portion, the stability is good when a heavy load is applied. In the case of this modified example , the jack 23 is prevented from hitting when the inner tank bottom plate 6 is lowered, and the jack 2 is
3 can be removed from above the inner tank bottom plate 6 through hole 7
Must be formed larger than the outer peripheral dimension of the jack 23.

FIG. 5 is a cross-sectional explanatory view showing a state in which the through hole provided in the inner tank bottom plate is closed. Lifting device 11 described above
After the inner tank bottom plate 6 is lowered and placed on the bottom cold insulating layer 3 by using, the post 9 and the elevator 10 are removed from the upper portion of the inner tank bottom plate 6 to close the through hole 7. In this case, the base plate 8 is as it is, the bottom cold insulation layer 3 below the inner tank bottom plate 6.
Keep this base plate 8 on the back metal 1 for welding.
6, the insertion plate 17 is formed in the through hole 7 and has a size reduced by the amount of the welded joint, and the outer peripheral edge and the inner tank bottom plate 6 are inserted.
Are carefully welded together. The through hole 7 can sufficiently secure the strength and the airtightness / liquid tightness required for the inner tank bottom plate 6 in order to butt-weld the insertion plate 17 with the base plate 8 as the backing metal 16 for welding. If the base plate 8 is formed by being embedded in the bottom cold insulation layer 3 as shown in the figure, there is no space around the inner tank bottom plate 6 after the descent of the inner tank bottom plate 6 to reduce the bottom cold insulation effect. And insert plate 1
The upper surface of 7 is flatly connected to obtain the inner tank bottom plate 6 excellent in strength and appearance. In addition, when the base plate 8 is directly placed on the bottom cold insulation layer 3 without being buried, there is an advantage that construction such as positioning and mounting becomes easy.

In this example, when the gantry 4 is removed, the case where the inner tank bottom plate 6 is lifted once by the lifting device 11 and the gantry 4 is removed and then lowered is described. If the can be folded, etc.,
The inner tank bottom plate 6 may be directly lowered without being raised. In this case, since the lifting device 11 and the like need only be lowered, it is possible to use only a simple lowering mechanism that utilizes its own load.

[0024]

[Effect of the invention] The bottom of the double shell storage tank according to the invention of claim 1
As mentioned above, the plate construction method is to penetrate the inner tank bottom plate on the frame.
The mouth is provided, removably attached to the inner tank bottom plate of the support member to become Porth <br/> preparative by penetrating the bottom cold layer in the through hole,該Po
By an elevator installed above the inner tank bottom plate by engaging the
Then lower the inner tank bottom plate, after placing the inner tank bottom plate on the bottom cold insulation layer, remove the lifting device including the post, and then,
Since the through hole is closed, the load on the bottom plate of the inner tank is
While supporting the
The bottom plate of the tank can be raised and lowered. In addition,
Install the strike from the top of the bottom plate of the inner tank through the through hole
And removal and removal can be performed easily and in a short time.
It In addition, a post is provided through the through hole, and it also moves up and down.
By installing the machine above the bottom plate of the inner tank,
Since the minimum size for passing through
Restoration is simple and easy, and workability is improved and economic efficiency is improved. That
Compared with the conventional wire suspension construction method, the above construction method has less reinforcement material for the inner tank bottom plate, and there is no work in high places to hang it from a high place, so that the inner tank bottom plate can be lowered efficiently, safely and economically. It can be installed. In addition, since it is not hung from the upper part of the side plate of either the inner or outer tanks or the roof with wires, it is possible to carry out the work independently without being restricted by the construction time of these, so the process is affected or delayed. Is not generated, and as a result, the whole process can be shortened. Further, as compared with the conventional construction method using a jack or a board frame, it is possible to perform construction efficiently and safely without a worker entering a narrow space below the inner tank bottom plate to perform complicated and dangerous work.

A double-shell storage tank inner bottom plate of the invention according to claim 2
The construction method of is the construction of the bottom plate of the double shell storage tank according to claim 1.
On the bottom cold insulation layer just below the through hole of the inner tank bottom plate in the method ,
Larger size than the through-hole to hold the above-mentioned post
The base plate is installed, the temperature to be engaged with the Posuto
The bottom plate of the inner tank is lowered by a descending machine and placed on the bottom cold insulation layer.
After removing the lifting device including the post,
Insert the insertion plate into the through hole located on the upper surface of the base plate,
Use backing metal for welding the base plate, the difference
Since the outer peripheral edge of the insert plate and the inner tank bottom plate are butt-welded and closed, the load of the inner tank bottom plate that is applied to each post when moving up and down the inner tank bottom plate is
With a base plate that is larger than the mouth , it poses
Receives a load on a large area, which makes it impossible for the cold insulation layer at the bottom.
Without applying a local load, it can be dispersed evenly and supported to prevent damage to the bottom cold insulation layer etc.
It In addition, the through hole is flattened by the inserted plate.
Blocked, and the outer peripheral edge of this insertion plate melts the above base plate.
It is used as a backing metal for contacting, and one side is completely melted from the top.
With the high quality welding, it is possible to sufficiently secure the strength and the airtightness / liquidtightness required for the inner tank bottom plate.
Then, the inner tank bottom plate with the through-hole closed and the upper surface of the insertion plate are flat.
Connected to the carrier to obtain an inner tank bottom plate with excellent strength and appearance.
To be

The lifting device of the invention according to claim 3 is a double shell
A support member for the inner tank bottom plate that penetrates through the through hole of the inner tank bottom plate of the storage tank.
Mounted on the bottom cold insulation layer so that it can be removed and installed upright.
Allowed inside so as to drop and Posuto provided, the inner tank bottom plate
Upper and elevator installed in the tank bottom plate top, the engaging portion provided on the Posuto to engage said with the elevator Posuto in
In the construction method of the bottom plate in the double shell storage tank according to claim 1 or 2,
Since the formation of the lifting device to be used, mounted installation and removal removal of Posuto and elevator, because made of the inner tank bottom plate upper simply and easily through the through port, using the lifting device
Thus , the inner tank bottom plate can be safely placed on the bottom cold insulation layer with good workability .

[Brief description of drawings]

FIG. 1 is an explanatory cross-sectional view showing a method of constructing a bottom plate in a double-shell storage tank according to the present invention.

FIG. 2 is an enlarged cross-sectional explanatory view showing a state in which a lifting device used in the construction method shown in FIG. 1 is installed.

FIG. 3 is a partially cutaway cross-sectional explanatory view showing a second embodiment of an elevating device according to the present invention.

FIGS. 4A and 4B are cross-sectional explanatory views with a part omitted showing the third and fourth embodiments of the lifting device according to the present invention.

FIG. 5 is an explanatory cross-sectional view with a part cut away showing a state in which a through hole provided in the bottom plate of the inner tank is closed.

FIG. 6 is a cross-sectional explanatory view showing a construction method of a conventional tank bottom plate in a double-shell storage tank.

[Explanation of symbols]

1,101 ... Outer tank 2, 102 ... Outer tank bottom plate 3, 103 ... Cooling layer at the bottom 4,104 ... Stand 5,105 ... Inner tank 6,106 ... Inner tank bottom plate 121 ... Reinforcement material 122 ... wire 123 ... Supporting part 7-through hole 8 ... Base plate 9 ... post 10, 10A, 10B, 10C, 10D ... Elevator 11 ... Lifting device 12 ... Guide roller 13 ... Wire 14 ... Engagement part 15 ... Winding machine 16 ... Back deposit 17: Insert plate 18 ... rack 19 ... Pinion 20 ... Drive device 21 ... Jack 22 ... Suspension arm 23 ... Jack 24 ... Support arm

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Claims (3)

(57) [Claims] 1. The inner tank bottom plate is welded on a gantry arranged on the bottom cold insulation layer of the double shell storage tank, the pedestal is removed, and the inner tank bottom plate is lowered by an elevating device and placed on the bottom cold insulation layer. in construction methods of the double-shelled reservoir tank bottom plate to a through hole provided in the inner tank bottom plate on said frame, support members of the inner tank bottom plate to the through-hole
It is attached to the bottom cold insulation layer so that it can be detached and attached , and it is installed on the inner tank bottom plate by engaging it.
The double shell characterized by lowering the inner tank bottom plate by means of an elevator, placing the inner tank bottom plate on the bottom cold insulation layer, removing the lifting device including the post, and then closing the through hole. Construction method of the bottom plate in the storage tank. Wherein the bottom cold layer immediately below the through-hole, the upper
It has a larger size than the through-hole to hold the post.
Install the base plate and move up and down to engage the above post
The bottom plate of the inner tank is lowered by a machine and placed on the bottom cold insulation layer.
After removing the lifting device including the post,
Insert the insertion plate into the through hole located on the upper surface of the base plate,
Use backing metal for welding the base plate, the difference
The method for constructing an inner tank bottom plate according to claim 1 , wherein the outer peripheral edge of the insert plate and the inner tank bottom plate are butt-welded and closed. 3. The bottom of the double shell storage tank according to claim 1 or 2.
Lifting device for use in construction methods of the plates, the double-shelled and Posuto provided freely attached remove the through hole of the inner tub bottom plate of the reservoir on the penetrating bottom cold layer, inner tank bottom so as to lower the inner tank bottom plate
The bottom plate in the double shell storage tank according to claim 1 or 2 , wherein the bottom plate is formed by an elevator installed on the upper part of the plate and an engaging portion provided on the post so as to engage the elevator with the post. Lifting device used for construction method.