JP3921649B2 - Inner tank side plate construction method of double shell tank - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for constructing an inner tank side plate of a double shell tank for storing a low temperature liquefied gas such as LNG.
[0002]
[Prior art]
A double shell tank 1 for storing a low-temperature liquefied gas or the like will be described with reference to FIG. 6 showing a conventional construction method. The double shell tank 1 includes a single shell of an outer tub 5 including a circular flat outer tank bottom plate 2, a cylindrical outer tub side plate 3, and a dome-shaped outer tub roof 4, and an outer tub of the outer tub 5. A single shell of an inner tank 10 provided with a circular flat inner tank bottom plate 7, a cylindrical inner tank side plate 8, and a dome-shaped inner tank roof 9 provided on the bottom cold insulation layer 6 laid on the bottom plate 2; Are formed by inner and outer tubs 5 and 10 of a double shell.
[0003]
In the construction method of the double shell tank 1, an outer tub 5 having an outer tub roof 4 is constructed prior to the construction of the inner tub 10, and the inner tub 10 is included in the constructed outer tub 5. There is a construction method of the outer tank advance type construction method to be constructed. An example outline of this outer tank preceding type construction method will be described with reference to FIG. FIG. 6 shows a process in the process of assembling the inner tank side plate 8 using the lifting machine 13, the bracket scaffold 14, and the frame scaffold 15.
[0004]
First, a circular flat outer tank bottom plate 2 disposed on a disk-shaped foundation and a cylindrical outer tank side plate 3 standing on the outer periphery of the outer tank bottom plate 2 are constructed. Next, a dome-shaped inner tub roof 9 (including a knuckle plate 9N constituting a connection portion with the inner tub side plate 8) and a dome-shaped outer tub placed on the inner tub roof 9 via a connecting material 11 Assembling the roof 4 with the bottom of the outer tub 5 and lifting the inner and outer tub roofs 4, 9 after the assembly is lifted by an air-raising method using air pressure or a jack-up method using a jack, The outer tank roof 4 in which the inner tank roof 9 is suspended by the connecting material 11 is attached to the upper part of the outer tank side plate 3, and the outer tank 5 is first constructed prior to the construction of the inner tank 10. And the bottom part cold insulation layer 6 is laid on the outer tank bottom plate 2 in the outer tank 5, and the inner tank bottom plate 7 is arrange | positioned on it.
[0005]
Next, a plurality of bracket scaffolds 14 are attached to the inner side surface of the outer tub side plate 3 along the circumferential direction, and a frame is formed along the circumferential direction on the inner tub bottom plate 7 inside the inner tub side plate 8 to be further constructed. A scaffold 15 is erected. A traveling type lifting machine 13 is attached to a ring-shaped rail 12 provided inside the outer tank roof 4, and the side plate piece 8 </ b> P is lifted by the lifting machine 13, and the bracket scaffold 14 and the frame scaffold 15 are used. The lowermost side plate 8L of the cylindrical inner vessel side plate 8 is erected on the outer peripheral portion on the inner vessel bottom plate 7, and the upper inner vessel side plate 8 is sequentially assembled and welded on the lowermost step side plate 8L. Then, the inner tank roof 9 suspended from the outer tank roof 4 via the connecting material 11 is lowered on the inner tank side plate 8 after the assembly welding of the uppermost side plate 8T is finished, and the inner tank side plate 8 and the inner tank side plate 8 The tank roof 9 is combined and the connecting material 11 is removed to construct the inner tank 10. Thus, this is a method for completing the double shell tank 1 composed of the inner and outer tanks 5 and 10. In addition, between the side part of the double shell tank 1 and the inner and outer tanks of the roof part, after the inner and outer tanks 5 and 10 are assembled, a cold insulating material such as pearlite particles is filled.
[0006]
Although not shown, a rail is provided on the outer tank roof at the upper part between the inner and outer tanks, a gondola is suspended from the rail, and a frame scaffold is provided on the inner tank side plate, and the gondola and the frame scaffold are attached. There is a conventional technique for constructing the inner tank side plate using it, and furthermore, a rail is provided on the outer tank roof at the upper part between the inner and outer tanks, and the wire suspended on this rail is passed through the upper opening of the inner tank side plate and inside the inner tank side plate Although there is a conventional technology that uses a suspended scaffolding and constructs the inner tank side plate using this hanging scaffold, the gondola is hung between both the inner and outer tanks and inside the inner tank side plate, and this inner and outer gondola is used. Thus, there has been no prior art for constructing the inner tank side plate.
[0007]
[Problems to be solved by the invention]
In the inner tank side plate construction method of the outer shell preceding type double shell tank shown in FIG. 6, the bracket scaffold 14 between the inner and outer tanks and the frame scaffold 15 inside the inner tank side plate are used as a working scaffold. In order to construct the inner tank side plate 8, a lot of labor and complicated work were required as described in detail below. That is, the bracket scaffold 14 positioned outside the inner tank side plate 8 needs to be attached in advance with a scaffold mounting jig 16 for fixing the bracket scaffold 14 to the inner surface of the outer tank side plate 3. Since there are many jigs 16, the work of attaching and removing is difficult, and it takes a lot of work to smooth the welded part removal trace of the jig 16 for attaching the scaffold. It took a great deal of labor to inspect whether cracks or other weld defects remained. In addition, the frame scaffold 15 standing on the inner side of the inner tank side plate 8 is high in size, large, and complicated, so that the work of assembling and dismantling is complicated and troublesome. In addition, as a method of mounting so as not to generate the jig trace of the above-mentioned scaffold mounting jig, a method of mounting using a magnet instead of welding is conceivable, but in the case of the inner tank side plate of the low temperature double shell tank , Because 9% nickel steel and stainless steel metal materials for low temperature liquids are used, these materials are difficult to attach magnets, and when TIG welding is performed, the adverse effect of magnetism on the welding arc Therefore, the use of a magnet is not preferable.
[0008]
Although not shown, the prior art in which a gondola is provided between the inner and outer tanks, and the inner tank side plate is constructed by providing a frame scaffold inside the inner tank side plate, the assembly and dismantling of the frame scaffold inside the inner tank side plate is performed. The work was complicated and time-consuming. Furthermore, although not shown, a rail is provided on the upper roof between the inner and outer tanks, a wire suspended on the rail is passed through the upper opening on the inner tank side plate, hung inside the inner tank side plate, and hung at the tip of this wire. Although there is a conventional technology that provides a scaffolding and constructs the inner tank side plate using this suspended scaffold, the construction method of this conventional technique still requires a bracket scaffold or the like when closing the upper opening of the inner tank side plate. Therefore, work such as installation and dismantling of the bracket scaffold and processing of jig traces was complicated and time-consuming.
[0009]
The present invention has been made in view of the above-described problems of the prior art, and can be easily and easily installed without using a scaffold using a scaffold mounting jig or a complex and large framed scaffold. It provides an inner tank side plate construction method for a double shell tank that can be constructed efficiently and economically using a gondola that is easy to use.
[0010]
[Means for Solving the Problems]
The inner shell side plate construction method of the double shell tank according to the present invention constructs an outer tank comprising an outer tank roof prior to the construction of the inner tank, and constructs the inner tank in the constructed outer tank. This is an inner tank side plate construction method for the double shell tank of the outer tank leading type construction method, and an outer rail is provided along the circumferential direction at the lower part of the outer peripheral edge of the outer tank roof, and this outer rail is disposed between the inner and outer tanks. The outer gondola is hung so that it can run in the circumferential direction and can move up and down in the vertical direction, and an inner rail is provided along the circumferential direction at the inner lower edge of the inner tank roof suspended from the outer tank roof. In this inner rail, an inner gondola located on the inner side of the inner tank side plate is suspended and installed so as to be able to run in the circumferential direction and vertically move up and down, and the inner tank using the outer gondola and the inner gondola The side plate is assembled, welded, and inspected.
[0011]
In addition, the outer gondola and the inner gondola used for the inner shell side plate construction method of the double shell tank are individually provided with suction connectors for temporarily connecting the outer gondola and the inner gondola to the inner tank side plate, respectively. It is a thing.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a method for constructing an inner tank side plate of a double shell tank according to the present invention will be described with reference to FIG. The construction method of this double shell tank 1 is the construction method of the outer tank preceding type construction method described above, and constructs the outer tank 5 provided with the outer tank roof 4 prior to the construction of the inner tank 10, The inner tank 10 is constructed in the constructed outer tank 5. FIG. 1 shows a process under construction in which the inner tank side plate 8 is assembled using the outer rail 22, the inner rail 32, the lifting machine 13, the outer gondola 18, and the inner gondola 19. The same reference numerals in the figure as those in FIG.
[0013]
A ring-shaped outer rail 22 is provided along the circumferential direction at the inner peripheral lower portion of the outer rim roof 4 of the outer tub 5 constructed in advance, and the outer rim of the inner tub roof 9 suspended on the outer tub roof 4 A ring-shaped inner rail 32 is provided at the inner lower portion along the circumferential direction, and an outer gondola 18 disposed between the inner and outer tubs 10 and 5 is vertically suspended from the outer rail 22 and installed. In 32, an inner gondola 19 located inside the inner tank side plate 8 is vertically suspended and installed. The inner and outer gondolas 18 and 19 are moved in the left and right circumferential directions and moved in the vertical and vertical directions by a controller (not shown) by button operation or the like attached to each gondola. Side plate pieces 8P are assembled from both the inside and outside both sides, and formed so as to perform welding work, inspection work, and the like.
[0014]
The process of constructing the inner tank side plate 8 using the inner and outer gondolas 18 and 19 will be described in more detail. From the outer tank side plate opening 17 provided at the lower part of the outer tank side plate 3, the inner tank side plate piece 8P is carried between the inner and outer tanks using a carriage or the like, and the outer rail 22 (used together with the rail 12 shown in FIG. 6 and described above). The side plate piece 8P is lifted using the traveling type lifting machine 13 installed in the inner tank and moved between the inner and outer tanks and conveyed to the assembly place of the inner tank side plate 8. During this transfer, the outer gondola 18 suspended from the outer rail 22 is run side by side to assist and guide the side plate pieces 8P so that they do not shake, and for further positioning during assembly. Can also be used. At the assembly place of the inner tank side plate 8, an operator who rides on the inner gondola 19 uses an assembly jig such as a U-shaped jig or a square arrow, and the upper edge of the inner tank side plate 8 and the adjacent inner tank. The edge of the side plate piece 8P is applied to the side edge of the side plate 8 to perform skin alignment and temporary assembly fixation. Since the assembly jig necessary for fixing the temporary assembly is mounted on the inner gondola 19 from the low position on the inner tank bottom plate 7 to the high position, the necessary quantity is used up each time. Like when using a scaffold, carry assembly jigs to a high place on the scaffold and temporarily place them, so that they do not get in the way of the operator or trip over them. There is no worry of dropping from a high place, so it is safe.
[0015]
A series of operations from the carrying-in to the temporary assembly fixing are sequentially repeated in the circumferential direction to assemble the circumferential ring-shaped inner tank side plate 8. Next, using the outer gondola 18, longitudinal welding and circumferential welding are performed from the outside of the inner tank side plate 8. After the outer welding is finished, the assembly jig is removed using the inner gondola 19, and then welding from the inner side of the inner tank side plate 8 is performed using the inner gondola 19. In addition, using the inner and outer gondolas 18 and 19, the inner and outer both side welded portions are inspected from both the inner and outer sides of the inner tank side plate 8.
[0016]
As described above, since the lifting machine 13 and the inner and outer gondolas 18 and 19 run side by side and are connected to each other, the construction work of the construction of the inner tank side plate 8 can be performed from inside and outside, so that the work efficiency is improved. For example, when the first layer welding of the submerged welding is performed from the outside of the inner tank side plate 8, the first layer welding is performed from the outside using the outer gondola 18, and the backing work is performed in parallel using the inner gondola 19 inside thereof. In addition, each work is linked so that the gouging work from the back side is sequentially performed in a delayed manner, and the inner and outer gondolas 18 and 19 can be moved continuously at the same height position and the same posture. Therefore, since stable work can be performed under certain good conditions, workability is good and the quality of the welded part is improved.
[0017]
By using the inner and outer gondolas 18 and 19, for example, when vertical welding of about 4 meters in height is performed, in the case of a conventional scaffold, it is for raising and lowering two steps of scaffolds corresponding to a height of 4 meters. In contrast to the need for lifting equipment, the gondolas 18 and 19 inside and outside can be moved up and down, and a range of 4 meters in height can be continuously constructed without going up and down the lifting equipment.
[0018]
Embodiment examples of the inner and outer gondolas 18 and 19 used in the inner shell side plate construction method for the double shell tank according to the present invention will be described with reference to FIGS.
[0019]
FIG. 2 shows a state where the inner and outer gondolas 18 and 19 are connected to the inner tank side plate, and FIG. 3 shows a state where the connection state of FIG. 2 is released. At the position of the inner tank side plate 8 direction of the inner and outer gondolas 18 and 19 suspended vertically, a suction connection tool 21 is provided which is extended and temporarily fixed in the horizontal direction. Further, a steady rest 23 is provided which projects horizontally from both end surfaces of the inner and outer gondolas 18 and 19 and contacts the surface of the inner tank side plate 8. The suction connector 21 and the steady rest 23 are projected so as to contact the surface of the inner tank side plate 8 when used as shown in FIG. 2, and are rotated and stored in the horizontal direction when not used as shown in FIG. Form as you can.
[0020]
As shown in FIG. 4 and FIG. 5 showing an enlarged view, the suction connector 21 includes a suction disk 24 made of a synthetic rubber having elasticity, and a cylindrical cylinder chamber 25 that is connected to the suction disk 24 in an airtight manner. A piston and a piston rod are provided in the cylinder of the cylinder chamber 25, and an operating lever 26 is connected to the tip of the piston rod. When temporarily using the suction connector 21, the internal piston is moved by operating the lever 26, and the inside of the closed space surrounded by the suction plate 24 and the inner tank side plate 8 is depressurized. When the suction plate 24 is brought into close contact with the inner tank side plate 8 and the temporary fixing is released, the suction is released by operating the lever 26. The suction connector 21 is connected to an adjustment tool 29 inside the inner and outer gondolas 18 and 19 as shown in the figure. The adjuster 29 is formed in a telescopic structure with a screw 27 and a handle 28 in order to adjust the distance between the surface of the inner tank side plate 8 and the tip of the suction connector 21. The handle 28 is turned to rotate the screw 27 at the tip thereof, and the suction connector 21 screwed and connected to the screw 27 is expanded and contracted in the horizontal direction. Further, the lower part of the adjustment tool 29 is attached to the gantry by a rotating structure attachment 30 and is formed in a structure that is rotated in the horizontal direction and stored in the inner and outer gondolas 18 and 19 as described above with reference to FIG. Note that the suction connector 21 is not limited to the above structure, and may be any structure as long as the inner and outer gondolas 18 and 19 can be sucked to the inner tank side plate 8.
[0021]
As described above, since the suction connection tool 21 for temporarily connecting the inner gondola 18 and the inner gondola 19 to the inner tank side plate 8 is provided, the temporary connection of the gondola can be easily and easily released, and the connection of the gondola can be released. Since it can be done easily and easily, the work efficiency when working on a gondola is improved. That is, when the inner tank side plate pieces 8P are temporarily aligned and temporarily assembled, the inner gondola 19 is temporarily fixed and connected, and the work scaffold is fixed and stable work can be performed. Next, when performing welding and inspection from the inside and outside, the temporary connection can be easily and easily released in a short time, and the continuous operation can be performed while moving the inside and outside gondolas 18 and 19, so that the work efficiency is improved. Since the working posture and the like are improved, the quality of the welded portion can be improved. Further, since no jig trace is generated on the surface of the inner tank side plate 8 of the connection trace of the suction connector 21, no magnetism that adversely affects the welding of the low-temperature material remains, so that a good surface state is maintained. be able to.
[0022]
Further, as shown in FIGS. 2 to 4, the steady rest 23 is formed in an L shape that rotates around a support shaft, and a contact member 31 is provided at the front end of the outer surface that contacts the inner tank side plate 8. When the steady rest 23 is used as shown in FIG. 2, it is rotated in the direction of the inner tank side plate 8 to bring the contact member 31 into contact with the surface of the inner tank side plate 8, and as shown in FIG. 3 and FIG. When the tool 23 is not used, it is formed so as to be rotated and stored inside the side surfaces of the inner and outer gondolas 18 and 19. The contact member 31 provided at the outer surface tip of the steady rest 23 is made of a synthetic rubber material, a synthetic resin material, or the like having elasticity, so that vibration and vibration are elastically absorbed so that work stability can be obtained. To form. When the steady rest 23 is used in combination with the above-described suction connector 21 and fixed temporarily, the steady operation is possible because the inner and outer gondola 18 and 19 are less likely to shake and vibrate. In addition, when the steady rest 23 is used separately from the suction connector 21, the inner tank side plate 8 is brought into contact with the inner tank side plate 8 to maintain a predetermined interval and the shaking is absorbed. Smooth work is possible. In addition, although illustration is abbreviate | omitted, when a rotatable roller is provided in the front-end | tip part of the steady rest 23 instead of the said contact member 31, when moving a long distance, making it contact with an inner tank side plate, an inner tank Since the frictional resistance with the side plate is further reduced, smoother movement is possible.
[0023]
【The invention's effect】
As is apparent from the description, the inner tank side plate construction method for the double shell tank according to the present invention is constructed by constructing an outer tank having an outer tank roof prior to the construction of the inner tank, and the constructed outer tank. The inner tank side plate construction method of the double shell tank of the outer tank leading type construction method for constructing the inner tank in the tank, and an outer rail is provided along the circumferential direction at the lower part inside the outer peripheral edge of the outer tank roof. An outer gondola placed between the inner and outer tubs on the outer rail is installed so that it can run in the circumferential direction and can be moved vertically in the vertical direction, and is installed in the lower part inside the outer rim of the inner tank roof suspended from the outer tank roof. An inner rail is provided along the direction, and an inner gondola located inside the inner tank side plate is suspended on the inner rail so as to be able to run in the circumferential direction and vertically move up and down. Construction of inner tank side plate, welding and inspection using inner gondola Runode, the inside and outside of the gondola by parallel running or cooperative, improved work efficiency since it is cooperative work from inside and outside. For example, backing work and gouging work at the time of first layer welding can be linked sequentially, and the inner and outer gondola can be moved continuously and constantly working at the same height position and posture, so stable under certain good conditions Work can be performed, so that workability is good and the quality of the welded portion is improved. Also, for example, when performing vertical welding with a height of about 4 meters, in the case of a conventional scaffold, a facility for raising and lowering two steps of the scaffold was required, but by using an inner and outer gondola, The upper and lower ranges of the two stages can be constructed continuously by moving the gondola up and down.
[0024]
In addition, since the inner and outer gondola is used with the inner tank side plate sandwiched as described above, the assembly jig required when aligning, temporarily assembling and temporarily fixing the side plate pieces of the inner tank is between the inner and outer tanks. Since the required quantity is loaded from the bottom and the bottom of the inner tank and then lifted all at once and the predetermined work is completed at one place from the inside and outside, the assembly jig will carry out the necessary quantity each time, so the conventional scaffolding is used. The jigs are lifted to a high place on the scaffold and temporarily placed so that they do not get in the way of the operator or stumbling. There is no worry about dropping it, so it is safe.
[0025]
In addition, even after the construction of the inner tank side plate, when re-checking the finish or inspecting the lower part of the inner surface of the roof, you can use the inner and outer gondola to move up and down, diagonally and circumferentially and work in a short time. . That is, it can be used for work such as inspection of the vicinity of the roof and side plates throughout the entire process without being limited by the conventional scaffold installation period.
[0026]
Since the inner shell side plate construction method of the double shell tank according to the present invention uses the inner and outer gondola with the inner tank side plate sandwiched as described above, it requires a complicated scaffold mounting jig between the inner and outer tanks as in the prior art. In addition, since there is no need for a large frame scaffold inside the inner tank side plate, a large space is secured between the inner and outer tanks and inside the inner tank, and a scaffold required for the work is obtained by this inner and outer gondola . Moreover, since there is no removal mark of a scaffold attachment jig and the removal mark is not smoothed or inspected, the construction efficiency of the inner tank side plate is good, and a smooth side plate surface can be held. A more economical inner tank side plate can be constructed with good work efficiency by using the inner and outer gondola provided with the inner tank side plate interposed therebetween. Moreover, since there is no work for assembling and dismantling the scaffold, the construction period can be shortened and the economy can be further improved.
[0027]
In addition, each of the outer gondola and the inner gondola used for the inner shell side plate construction method of the double shell tank is provided with a suction connector for temporarily fixing and connecting the outer gondola and the inner gondola to the inner tank side plate, respectively. Therefore, the temporary fixing connection of the gondola can be easily and easily disconnected, and the disconnection of the gondola can be easily and easily released, so that the work efficiency when riding on the gondola is improved. In other words, when the inner tank side plate pieces are put together and temporarily assembled, the inner and outer gondola provided with the inner tank side plate sandwiched between them can be temporarily fixed and connected without moving, and then welding and inspection are performed. In this case, since the temporary work connection can be easily and easily released and moved continuously, the work efficiency is improved and the quality of the welded part is improved. In addition, no jig trace is generated in the connection trace of the suction connector, and no magnetism that adversely affects welding remains, so that a good surface state can be maintained.
[0028]
[Brief description of the drawings]
FIG. 1 is a schematic overall cross-sectional side view showing an embodiment of an inner tank side plate construction method for a double shell tank according to the present invention.
FIG. 2 is a perspective explanatory view showing a state in which an inner and outer gondola used in the inner shell side plate construction method of the double shell tank according to the present invention is temporarily connected to the inner tank side plate.
3 is a perspective explanatory view showing a state in which the temporarily fixed connection state of FIG. 2 is released. FIG.
FIG. 4 is an explanatory side view with a part removed showing a state where inner and outer gondola are temporarily connected to an inner tank side plate.
FIG. 5 is an explanatory side view showing a suction connector provided on an inner and outer gondola.
FIG. 6 is a schematic overall cross-sectional side view illustrating a conventional method for constructing an inner tank side plate of a double shell tank.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Double shell tank 2 Outer tank bottom plate 3 Outer tank side plate 4 Outer tank roof 5 Outer tank 6 Bottom cool layer 7 Inner tank bottom plate 8 Inner tank side plate 8L Lowermost stage side plate 8T Uppermost stage side plate 8P Side plate piece 9 Inner tank roof 9N Knuckle plate DESCRIPTION OF SYMBOLS 10 Inner tank 11 Connecting material 12 Rail 13 Lifter 14 Bracket scaffold 15 Frame scaffold 16 Scaffold mounting jig 17 Outer tank side plate opening 18 Outer gondola 19 Inner gondola 20 Wire 21 Adsorption connection tool 22 Outer rail 23 Stabilization tool 24 Adsorption Panel 25 Cylinder chamber 26 Lever 27 Screw 28 Handle 29 Adjustment tool 30 Mounting tool 31 Contact member 32 Inner rail

Claims (2)

Prior to the construction of the inner tank, an outer tank with an outer tank roof is constructed, and the inner tank side plate construction method for the double shell tank of the outer tank advance type construction method in which the inner tank is constructed within the constructed outer tank. In addition, an outer rail is provided along the circumferential direction at the lower part of the outer peripheral edge of the outer tub roof, and an outer gondola disposed between the inner and outer tubs on the outer rail can run in the circumferential direction and move vertically in the vertical direction. An inner rail is provided along the circumferential direction at the lower part of the inner edge of the inner tank roof that is suspended and installed on the outer tank roof, and an inner gondola located on the inner side of the inner tank side plate is provided on the inner rail. It is installed by being suspended so that it can run in the circumferential direction and move up and down in the vertical direction, and the assembly, welding and inspection of the inner tank side plate are performed using the outer gondola and the inner gondola. Construction method of inner side plate of double shell tank. 2. The double shell tank according to claim 1, wherein the outer gondola and the inner gondola are each provided with a suction connector for temporarily fixing and connecting each of the outer gondola and the inner gondola to the inner tank side plate. Tank side plate construction method.

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