JP6663204B2 - Construction method of cylindrical tank - Google Patents

Description

  The present invention relates to a method for constructing a cylindrical tank.

  A cylindrical tank having a double shell structure having an inner tank and an outer tank is used for storing low-temperature liquids such as LNG (liquefied natural gas) and LPG (liquefied petroleum gas). Patent Document 1 discloses a construction method for a cylindrical tank having an inner tank made of metal and an outer tank made of concrete.

  Patent Literature 1 discloses a method of simultaneously constructing a metal inner tank and a concrete outer tank in order to shorten the construction period of a cylindrical tank. Specifically, a gantry is installed along the inner peripheral surface of the outer tub lower stage, and then on this gantry, the inner tank side plate is raised by the jack-up device, and the next to the lower side of the raised inner tub side plate. Welding of the inner tank side plate is alternately repeated to assemble the inner tank. In parallel with such assembling of the inner tank, the outer tank is also constructed sequentially from the lower stage to the uppermost stage.

  In such a cylindrical tank construction method, an inner tank side plate to be next attached is taken in from a construction opening into a space below the inner tank side plate raised by the jack-up device. Then, the taken inner tank side plate is assembled in an annular shape along the circumferential direction of the outer tank, and the vertical (vertical) seam (vertical seam) between the adjacent inner tank side plates is welded and raised. Weld also to the tank side plate.

JP 2012-149416 A

  By the way, in order to perform the welding between the inner tank side plates and the inspection after the welding, for example, a scaffold for performing the welding and a scaffold for performing the inspection of the welding location and the like are required. In particular, regarding welding of the vertical seam and inspection after the welding, it is necessary that the welding line (vertical seam) and the spot after the welding can be visually observed and touched by hand. Therefore, for example, a plurality of steps (two to three steps) of scaffolds are installed on the inner tank side plate having a height of 4 m in the height direction so that work can be easily performed on the entire length (entire area) in the height direction. There is a need to.

  However, the height of a general bite frame assembled on the inner side of the inner tank side plate is standardized to a pitch of 1800 mm. Therefore, the height of each step of the bite frame is determined by welding or inspection after welding. There is a problem that the scaffold is often shifted from the preferable height of the scaffold, and the access to the scaffold cannot be used directly because of poor access.

  Further, the inner tank side plate has a different thickness depending on the height position in the inner tank, and therefore, for manufacturing reasons, the lateral width also differs depending on the height position in the inner tank. That is, the plate thickness is thick and the width is narrow (short) on the lower side of the inner tank, and the plate thickness is thin and wider (long) on the upper side of the inner tank. Therefore, the position of the vertical seam (weld line) changes every time the step of the inner tank side plate changes, that is, each time the height position in the inner tank changes, and therefore, the scaffold for welding the vertical seam and subsequent inspection. Also needs to be changed each time the inner tank side plate changes. However, in order to change the position of the scaffold in this way, it is necessary to reassemble the scaffold, which is one of the factors that hinder shortening of the construction period.

  That is, conventionally, since the mounting member was welded to the inner tank side plate and the scaffold was mounted on this mounting member, it was necessary to re-weld the mounting member to change the position of the scaffold. In addition, when jacking up or jacking down the inner tank side plate, it was necessary to remove the mounting member so that the mounting member did not interfere with other portions. However, since it is necessary to weld or remove the mounting member also when reassembling the scaffold, the current situation is that such reassembly of the scaffold prevents shortening of the construction period.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method of constructing a cylindrical tank in which a scaffold can be easily reassembled, for example, for alignment with a vertical seam. It is in.

  The method for constructing a cylindrical tank according to the present invention is a method for constructing a cylindrical tank having an inner tank and an outer tank, wherein the inner tank side plate taken into the outer tank is raised, and the raised inner tank is raised. And a step of assembling the inner tank by alternately repeating the connection of the next inner tank side plate to the lower side of the side plate, and a scaffold for performing work on the inner tank side plate, with respect to the inner tank side plate. By using a vertical scaffold having a supporting frame located on the opposite side of the outer tub or a frame detachably attached to the outer tub and a scaffold plate detachably wrapped around the frame, the inner tub is used. It is formed between the side plate and the outer tank or between the inner tank side plate and the support frame.

  In the method for constructing a cylindrical tank, it is preferable that a step of installing a gantry supporting the inner tank side plate inside the outer tank is provided as a pre-process of assembling the inner tank.

  In the method for constructing a cylindrical tank, it is preferable that the vertical scaffold has a side plate abutting member extending from the frame so as to extend and contract and abut against the inner tank side plate.

  Further, in the method for constructing the cylindrical tank, the vertical scaffold between the inner tank side plate and the outer tank extends and contracts from the frame so as to abut against the outer tank. It is preferable to have

  According to the present invention, according to the method for constructing a cylindrical tank of the present invention, a scaffold for performing an operation on the inner tank side plate is provided between the inner tank side plate and the outer tank or the support frame opposed thereto. Since it is formed by a vertical scaffold having a frame detachably attached to a tank or a support frame and a scaffold plate detachably hung on the frame, for example, when welding a vertical seam of an inner tank side plate. For example, by simply installing a frame at a desired position and hanging a scaffold plate on the frame, a vertical scaffold can be easily assembled on site. Therefore, the vertical seam of the inner tank side plate can be easily welded and inspected after welding by using the vertical scaffold, and the scaffold can be easily reassembled in accordance with the position of the vertical seam. Furthermore, since it is not directly attached to the inner tank side plate, it is not affected by, for example, jacking up or jacking down of the inner tank side plate, and it is not necessary to reassemble the scaffold, so that the construction period can be shortened.

It is a longitudinal section for explaining a process in one embodiment of the present invention. It is a longitudinal section for explaining a process in one embodiment of the present invention. It is a longitudinal section for explaining a process in one embodiment of the present invention. It is a principal part longitudinal cross-sectional view for demonstrating the attachment state of a knuckle support. It is a longitudinal section for explaining a process in one embodiment of the present invention. It is a longitudinal section for explaining a process in one embodiment of the present invention. FIG. 2 is a vertical sectional view of a main part for describing a process in one embodiment of the present invention. It is a longitudinal section for explaining a process in one embodiment of the present invention. It is a longitudinal section for explaining a process in one embodiment of the present invention. It is a principal part longitudinal cross-sectional view which shows schematic structure of an example of the vertical scaffold formed on a base with a leg. It is a principal part longitudinal cross-sectional view which shows the schematic structure of an example of the horizontal scaffold formed on a base with a leg. It is a longitudinal section for explaining a process in one embodiment of the present invention. It is a longitudinal section for explaining a process in one embodiment of the present invention. It is a longitudinal section for explaining a process in one embodiment of the present invention. It is a longitudinal section for explaining a process in one embodiment of the present invention. It is a longitudinal section for explaining a process in one embodiment of the present invention. It is a longitudinal section for explaining a process in one embodiment of the present invention. It is a longitudinal section for explaining a process in one embodiment of the present invention.

  Hereinafter, an embodiment of a method for constructing a cylindrical tank according to the present invention will be described in detail with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size. In the following description, as a cylindrical tank, a ground-type PC (prestressed concrete) double shell storage tank that stores LNG is exemplified.

First, as shown in FIG. 1, construction of a substantially disk-shaped base plate (the bottom of a concrete outer tank) 1 is performed, and a bottom liner (not shown) is formed on the upper surface thereof. At this time, in the present embodiment, the inner tank anchor strap 2 is installed inside the outer peripheral edge of the base plate 1 along the circumferential direction of the base plate 1.
Next, a part of the outer tank side wall 3 (PC wall), for example, a fifth step of the side wall 3 formed by stacking a total of nine steps (outside the inner tank anchor strap 2) on the outer peripheral edge of the base plate 1. Steps up to # 5) are formed.

  In addition, in a part of the side wall 3 (PC wall) of the outer tank formed here, a construction port 4 is formed on the lower side, for example, from the second to the third step. In addition, since a part of the side wall 3 is stacked with the side walls of the remaining steps to finally form the side wall 3 having nine steps, it is necessary to assemble a mold for the remaining steps. The suspension scaffold 5 is installed on a part of the side wall 3, for example, at a portion of the fourth stage or higher.

  After a part of the side wall 3 of the outer tub is formed in this way, a plurality of pedestal mounts 6 (bases) for assembling the inner tub side plate are installed on the inner peripheral surface side of the side wall 3 along the circumferential direction. The pedestal 6 is a portal gantry for supporting an inner tank side plate described later. The pedestal 6 is set on the base plate 1 so as to straddle an annular area X where a metal and cylindrical inner tank formed by combining a plurality of inner tank side plates is finally lowered. I do. After forming and installing the legged base 6, or following the formation of the legged base 6, a vertical scaffold is formed on the legged base 6 as described later.

  Next, apart from the formation of a vertical scaffold described later, concrete is cast on a part of the side wall 3 as shown in FIG. 2 to form a sixth-stage (# 6) side wall. In the construction of such a side wall 3, as the upper side is sequentially formed, the suspension scaffold 5 is also sequentially moved upward.

In parallel with this, a plurality of inner tank side plates 7 which become a part of the side wall of the inner tank are erected along the circumferential direction of the side wall 3 on the base 6 with legs, and these inner tank side plates 7 are adjacent to each other. Welded together laterally. Thereby, each inner tank side plate 7 is assembled in an annular shape. In addition, such welding is mainly performed using a lower scaffold (lower outer scaffold, lower inner scaffold) described later. The inner tank side plate 7 assembled here corresponds to the uppermost step (in the present embodiment, the ninth step [# 9]). The inner tank side plate 7 is formed of a Ni steel material or the like having excellent toughness and strength.
Inside the side wall 3, the roof base 8 is assembled at the center of the basic slab 1.

  Next, as shown in FIG. 3, each plate of the knuckle plate 9 (knuckle portion) is attached to the upper end of the uppermost inner tank side plate 7, thereby assembling the knuckle plate 9 and attaching it to the upper end of the inner tank side plate 7. Attach to The knuckle plate 9 is formed so as to be curved downward at an outer peripheral edge of an inner tank roof described later, and has an upper end edge of the uppermost inner tank side plate 7 at a lower end edge as described above. Unit is connected.

  A knuckle support 10 is attached to the outer peripheral surface of the knuckle plate 9 as shown in FIG. In the present embodiment, a plurality (for example, 30) of knuckle supports 10 are provided at equal intervals along the circumferential direction of the knuckle plate 9. The knuckle support 10 is made of a steel plate for forming a suspended portion connected to a jack-up device to be described later, and includes a pair of support plates 10a and 10a formed in a substantially triangular shape in a side view. A suspended plate 10b having a substantially square shape in a plan view sandwiched between the support plates 10a and connected to the upper surface side of the suspended plate 10b to connect the suspended plate 10b between the support plate 10a and the suspended plate 10b. And a reinforcing plate 10c for reinforcement.

  One side of the support plate 10a, which is curved in accordance with the curved shape of the knuckle plate 9, is joined to the curved surface of the knuckle plate 9, and is attached and fixed by welding or the like. The suspended plate 10b and the reinforcing plate 10c are connected and fixed to each other by welding or bolting between the support plates 10a in a state of being connected to each other by welding or the like. Here, the suspended plate 10b is fixed between the support plate 10a and the support plate 10a with its outer end (the end on the side wall 3 side) coinciding with the outer end of the support plate 10a. The suspended plate 10b is formed with a notch (not shown) that opens toward the side opposite to the knuckle plate 9, that is, toward the side wall 3 of the outer tub, and this notch is used for a jack-up device described later. It is a hanging point to be connected.

Next, as shown in FIG. 5, the inner tank roof block is mounted on the roof stand 8, and the inner tank roof 14 (tank roof portion) is assembled.
Also, an aerial work vehicle (not shown) is mounted on the basic slab 1. Further, a part of the annular portion 16 is constructed in the annular region X below the pedestal 6 to form the annular portion 16.
Also, the side walls 3 of the outer tub are sequentially stacked upward, and the outer tub side walls 3 are constructed up to the ninth stage (# 9), which is the final stage. At this point, the suspension scaffold 5 for forming the side wall 3 remains in a state of being assembled from the sixth step to the seventh step or more, for example.

  Next, as shown in FIG. 6, the jack-up device scaffold 17 is placed on the knuckle plate 9 in a state of being separated from the inner peripheral surface of the side wall 3 of the outer tub and at a height not interfering with the suspension scaffold 5. Assemble. The jack-up device scaffold 17 is formed in a ring shape along the circumferential direction of the knuckle plate 9 formed in a ring shape, thereby preventing the jack-up device scaffold 17 from falling in the radial direction. In assembling, the knuckle support 9 is supported almost entirely, and a fall prevention member (not shown) is provided between the knuckle plate 9 and the inner tank roof 14 so that the knuckle plate 9 and the inner tank are provided. The scaffold 17 for the jack-up device is formed while being fixed to the roof 14. In this embodiment, as shown in FIG. 6, the jack-up device scaffolding 17 is assembled corresponding to substantially the fourth (# 4) to fifth (# 5) stages of the side wall 3 of the outer tub.

  Then, using the jack-up device scaffolding 17, the hanging racks 18 (hanging portions) are equally spaced in the circumferential direction of the side wall 3 at a predetermined position of the side wall 3, in the fifth embodiment (# 5) in the present embodiment. Are installed as shown. That is, the suspension base 18 is firmly and removably fastened and fixed to, for example, an anchor plate or the like embedded in the side wall 3 in advance, and protrudes substantially horizontally from the side wall 3 toward the inside.

  Next, a jack-up device 19 is attached between the suspension base 18 and the suspension plate 10b of the knuckle support 10. The jack-up device 19 is configured as a center hole jack as shown in FIG. 7, and has a jack body 20a engaged and supported by the suspension base 18, an upper end attached to the jack body 20a, and a lower end It has a jack-up rod 20 attached to the suspended plate 10b of the knuckle support 10, and a nut 19a for attaching the lower end of the jack-up rod 20 to the suspended plate 10b. In FIG. 7, the illustration of the jack-up device scaffold 17 is omitted for easy viewing.

  The jack-up device 19 is attached by suspending the jack-up rod 20 in a state where the jack body 20a is engaged with and fixed to the suspension base 18, and the lower end of the jack-up rod 20 is attached to the knuckle support 10. It is inserted into the notch of the suspended plate 10b. Then, the lower end of the jack-up rod 20 is fixed to the suspended plate 10b by a nut 19a prepared in advance.

  As shown in FIG. 7, a gondola rail 11 is provided below the jack-up device 19. The gondola rail 11 is attached to all the knuckle supports 10 so as to be annularly arranged outside the knuckle plate 9 along the circumferential direction of the knuckle plate 9. A hook 12 is suspended from the gondola rail 11 so as to be movable along the circumferential direction and to be able to move up and down. A knuckle inner rail 13 is annularly arranged inside the knuckle plate 9 along its circumferential direction. An appropriate hanging tool (not shown) is also attached to the knuckle inner rail 13. The use of the gondola rail 11 and the knuckle inner rail 13 makes it possible to raise and lower a welding device, a welding inspection device, various equipments, and the like, and to convey it in a circumferential direction.

  In this way, a plurality of jack-up devices 19 are installed at predetermined intervals in the circumferential direction of the side wall 3 of the outer tub, and are further attached to the suspended plate 10b of the knuckle support 10, respectively. Then, as shown in FIG. Remove it. When the roof frame 8 is removed, the weight of the tank component is held by the plurality of jack-up devices 19.

  Here, as shown in FIG. 6, the position where the suspension base 18 is provided is the fifth step (# 5) of the side wall 3, and the position where the knuckle support 10 is provided is the third step (# 3) of the side wall 3. , The jack-up rod 20 is formed to have a sufficient length corresponding thereto. However, the jack-up rod 20 having such a length is located immediately above the jack-up rod 20 when the jack-up device 19 is operated to raise the jack-up rod 20 as described later. The suspension scaffold 5 interferes.

Therefore, the jack-up rod 20 is formed by connecting a plurality of rods 20b in the length direction as shown in FIG. 7, and these are configured to be detachable by screwing or the like.
Thus, when the jack-up rod 20 is raised, the rod 20b protruding above the suspension base 18 is cut off from the lower rod 20b, thereby preventing the jack-up rod 20 from interfering with the suspension scaffold 5. can do. Reference numeral 21 in FIG. 6 denotes a suspension balance for lifting and suspending each component of the jack-up device 19 and for suspending the separated rod 20b, and one end of a balance bar 21a. This is a known device having a weight 21b in its portion. The hanging balance 21 is hung by a crane (not shown), and thereby controls operations such as vertical movement and horizontal movement.

  In addition, during such a process, on the basic slab 1, the cold insulation work of the annular portion 16 and the cold insulation work of the central portion are performed in parallel. As shown in FIG. 7, the cold insulation work of the annular portion 16 is performed by assembling a pearlite concrete block 23 a, a pearlite concrete block 23 b, and a structural lightweight concrete block 24 on the bottom cooling and heat resistance reducing material 22 under the pedestal 6 with legs. This is performed by mounting an annular plate 16a thereon. The annular portion 16 ultimately supports the assembled inner tank side plate 7, has a thick annular plate 16 a, and also has a cool structure formed of a hard material such as a concrete block.

  Next, as shown in FIG. 8, the knuckle plate 9 is lifted by the jack-up device 19, so that the knuckle plate 9 and the inner tank roof 14, the inner tank side plate 7, the knuckle support 10, and the jack-up device are supported. The tank component Y including the scaffold 17 is raised. Specifically, the jack body 20a is driven to rotate forward to raise the jack-up rod 20, and the tank component Y being assembled with the knuckle support 10 is jacked up.

  Here, the knuckle plate 9 lifted by the jack-up device 19 is for connecting the inner tank roof 14 and the inner tank side plate 7, and is sufficiently thicker and stronger than the inner tank side plate 7, Even if the weight including the inner tank side plate 7, the inner tank roof 14, and the jack-up device scaffolding 17 is added, there is no fear of buckling or the like.

  When the jack-up device 19 raises the tank component Y by almost one step of the inner tank side plate 7, the space formed below the inner tank side plate 7, that is, the space on the pedestal base 6, is filled with the next inner tank side plate 7. Carry in. The inner tank side plate 7 is carried in through a construction port 4 provided in the side wall 3. A first transport device (not shown) is provided around the construction port 4, and the inner tank side plate 7 is sequentially transported from the outside of the side wall 3 through the construction port 4 to the base 6 with legs by the transport device. You. Further, on the pedestal 6, a second transfer device (not shown) is provided along the circumferential direction of the side wall 3. The second transport device is configured to have a rail (not shown) along the circumferential direction of the side wall 3 and the like. The second transport device transfers the inner tank side plate 7 transported onto the pedestal base 6 to the side wall 3. Are sequentially transported in the circumferential direction.

  Next, the inner tank side plate 7 conveyed by the second conveying device is erected on the pedestal 6 and is arranged in an annular shape below the jacked up inner tank side plate 7. Then, as shown in FIG. 9, these inner tank side plates 7 are welded integrally with each other adjacent to each other in the lateral direction, and the inner tank side plates 7 arranged vertically are also welded together. Are formed in an integral cylindrical shape. That is, the 8th (# 8) inner tank side plate 7 is attached below the 9th (# 9) inner tank side plate 7, which is the uppermost step.

  Here, such operations as welding of the inner tank side plates 7 adjacent in the lateral direction (vertical seam welding) and inspections related to this welding, and welding of the inner tank side plates 7 arranged vertically (horizontal seam welding) Work such as inspection related to welding and the like is performed using a scaffold formed on the legged base 6 after installing the legged base 6. Specifically, a vertical scaffold is mainly used for work related to vertical seam welding, and a horizontal scaffold is mainly used for work related to horizontal seam welding.

FIG. 10 is a view showing a schematic configuration of an example of a vertical scaffold formed on the frame 6 with legs. In FIG. 10, reference numeral 60 denotes an inner vertical scaffold formed and arranged inside the inner tank side plate 7, and reference numeral 70 denotes It is an outer vertical scaffold formed and arranged outside the inner tank side plate 7. In FIGS. 1 to 9 and FIGS. 11 to 18 described later, the illustration of the inside vertical scaffold 60 and the outside vertical scaffold 70 is omitted.
The inner vertical scaffold 60 is installed on the pedestal 6 and at the same time, the support frame scaffold 41 (support frame) and the inner peripheral surface of the inner tank side plate 7 which are located on the opposite side of the outer tank with respect to the inner tank side plate 7. The frame 61 includes a frame 61 detachably attached to the support frame scaffold 41 and a scaffold plate 62 detachably attached to the frame 61.

  The support frame scaffold 41 is a scaffold made of a general bite frame, and a building frame, braces, a horizontal pipe, a steel plate, and the like are assembled and installed on the gantry body 6a at the site. That is, the torii-shaped building frames are connected by horizontal pipes or diagonal braces that are horizontally arranged, and a steel plate is laid on the horizontal pipes to install the support frame scaffolding 41. The steel plate forming each step is formed of a metal mesh plate, for example, an expanded metal or the like, for weight reduction.

  The frame body 61 is a rectangular parallelepiped formed by assembling pipes vertically and horizontally. For example, vertical pipes 61a are arranged in front, rear, left and right, and these vertical pipes 61a are connected by a horizontal pipe 61b. Alternatively, a pair of pipe units in which a pair of vertical pipes 61a are connected by a plurality of horizontal pipes 61b in the vertical direction are prepared, and the pair of pipe units oppose each other left and right (in the circumferential direction of the side wall 3 of the outer tank). The front and rear sides between these pipe units are connected to each other by a horizontal pipe 61b.

  A scaffold plate 62 is bridged between the horizontal pipes 61b that are arranged on the left and right and extend in the front-rear direction, and the scaffold plate 62 becomes a substantial scaffold. Therefore, a plurality of horizontal pipes 61b for supporting the scaffold plate 62 are provided in the height direction of the vertical pipe 61a. Generally, the inner tank side plate 7 has a height of one stage of about 4 m. Therefore, in order to easily perform welding (vertical seam) and inspection of the vertical seam of the inner tank side plate 7 from the bottom to the top, it is necessary to provide two positions in the vertical direction with respect to the inner tank side plate 7 for one stage. It is preferable to be able to access from about five locations separated from the location. Therefore, a plurality of horizontal pipes 61b for supporting the scaffold plate 62 are arranged at a pitch of about 2 to 5 steps, for example, about 1.5m, in the height direction with respect to the vertical pipe 61a. However, in order to use this horizontal pipe 61b also as a ladder, it is more preferable to arrange the horizontal pipe 61b in multiple stages by narrowing the vertical pitch.

  As shown in FIG. 10, the frame 61 is provided with two vertical pipes 61 a on the support frame scaffold 41 side detachably attached to the vertical frame of the support frame scaffold 41 by, for example, clamps 63 at two upper and lower locations. Further, the frame body 61 is provided with side plate abutting members 64 that abut against the inner tank side plate 7 on a plurality of upper and lower horizontal pipes 61b that constitute the frame body 61. The side plate abutting member 64 is disposed on the inner tank side plate 7 side of the horizontal pipe 61b, and is a male screw (not shown) that is screwed into a female screw (not shown) formed in the horizontal pipe 61b. ). The side plate butting member 64 is integrally provided with a butting plate (not shown) that abuts on the inner tank side plate 7 at its tip.

  With such a configuration, the side plate butting member 64 is housed in the horizontal pipe 61b when the inside vertical scaffold 60 is installed, and after the inside vertical scaffold 60 is installed, the butting plate is turned and the horizontal pipe 61b is turned. 61b. That is, the side plate abutting member 64 is configured to extend from the frame body 61 so as to be able to expand and contract. By extending the side plate abutting member 64 and abutting the abutting plate against the inner tank side plate 7 in this manner, the inner vertical scaffold 60 is stabilized between the support frame scaffold 41 and the inner tank side plate 7. Thus, the swing of the inner vertical scaffold 60 due to wind or the like is eliminated.

  The outer vertical scaffold 70 is formed between the outer peripheral surface of the inner tank side plate 7 and the side wall 3 of the outer tank, and is attached to the frame member 71 fixed to the inner surface of the side wall 3 of the outer tank. And a scaffold plate 72 that is detachably attached to the frame 61. The frame member 48 is formed by a plurality of angle members arranged at substantially equal intervals in the circumferential direction of the side wall 3, and is formed by erecting the angle member in the vertical direction and fixing the angle member to the side wall 3. That is, the frame member 48 is detachably fixed to the inner surface of the side wall 3 by, for example, bolting an angle member to an embedding plate (not shown) embedded in the side wall 3 in advance.

  The frame 71 has the same configuration as the frame 61 of the inner vertical scaffold 60, and is formed by assembling pipes vertically and horizontally. Then, as shown in FIG. 10, the frame 71 has a vertical pipe 71a on the side wall 3 side detachably attached to the frame member 48 by, for example, an attachment member 73 such as a clamp at two upper and lower locations.

  Further, the frame body 71 is provided with side plate abutting members 74 that abut against the inner tank side plate 7 on a plurality of upper and lower horizontal pipes 71b constituting the frame body 71. The side plate abutment member 74 is formed in the same manner as the side plate abutment member 64 of the inner vertical scaffold 60, and is provided with a female screw portion (not shown) formed in the horizontal pipe 71b on the inner tank side plate 7 side. It is a rod-shaped body having a male screw portion (not shown) to be screwed. The side plate butting member 74 is integrally provided with a butting plate (not shown) that comes into contact with the inner tank side plate 7 at its tip.

  The side plate abutting member 74 having such a configuration is housed in the horizontal pipe 71b when the outer vertical scaffold 70 is installed, and the outer vertical scaffold 70 is installed when the outer vertical scaffold 70 is installed. After that, the butting plate is turned to extend from the horizontal pipe 71b. That is, the side plate butting member 74 is configured to extend from the frame 71 so as to be able to expand and contract.

  Further, the frame body 71 is provided with an outer tank abutting member 75 which abuts on the side wall 3 of the outer tank on some of the upper and lower horizontal pipes 71b constituting the same. The outer tank abutting member 75 is formed similarly to the side plate abutting member 74, and is a male screw that is screwed into a female screw portion (not shown) formed in the horizontal pipe 71b on the inner tank side plate 7 side. It is a rod-shaped body having a portion (not shown). The outer tank abutting member 75 is also integrally provided with an abutting plate (not shown) that abuts against the end of the outer tank abutting member 75 against the side wall 3 of the outer tank.

  The outer tank abutting member 75 having such a configuration is also housed in the horizontal pipe 71b when the outer vertical scaffold 70 is installed, similarly to the side plate abutting member 74, and the outer vertical scaffold 70 is installed. After that, the butting plate is turned to extend from the horizontal pipe 71b. That is, the outer tank abutting member 75 is configured to extend from the frame 71 so as to be able to expand and contract. Therefore, after attaching the frame body 71 to the frame member 48 with the attaching member 73, the side plate abutting member 74 and the outer tank abutting member 75 are respectively extended, and the abutting plate is attached to the inner tank side plate 7 and the side wall of the outer tank. The outer vertical scaffold 70 can be held in a stable state between the outer tank side wall 3 and the inner tank side plate 7 by abutting the outer vertical scaffold 3. Shaking can be eliminated.

  Note that the scaffold plate 62 and the scaffold plate 72 of the inner vertical scaffold 60 and the outer vertical scaffold 70 are laid on horizontal pipes 61b (71b) having a height (step) serving as a scaffold for actual work. In the upper stage, the space between the horizontal pipes 61b (71b) is opened without suspending the scaffold plate 62 (72) so as not to hinder the work.

As described above, the vertical scaffold having such a configuration is mainly used for work related to vertical seam welding, and the horizontal scaffold is used for work related to horizontal seam welding. Therefore, after the operation relating to the vertical seam welding is completed, both the inner vertical scaffold 60 and the outer vertical scaffold 70 are once removed.
That is, each abutment member is contracted and stored in the horizontal pipe, the clamp 63 and the attachment member 73 are removed, the scaffold is removed from the frame, and the frame is appropriately disassembled. The gantry body 6a is cleared to a position where it does not interfere with the operation related to the horizontal seam welding. Then, after removing the inner vertical scaffold 60 and the outer vertical scaffold 70 together, or before assembling the inner vertical scaffold 60 and the outer vertical scaffold 70, the work related to the horizontal seam welding is performed. Assemble the horizontal scaffold.

  FIG. 11 is a diagram showing a schematic configuration of an example of a horizontal scaffold formed on the legged base 6 as a part of the legged base 6, and reference numeral 40 in FIG. 11 is formed and arranged inside the inner tank side plate 7. Reference numeral 50 denotes an outer horizontal scaffold formed and arranged outside the inner tank side plate 7. In FIGS. 1 to 9 and FIGS. 12 to 18 described later, the illustration of the inner horizontal scaffold 40 and the outer horizontal scaffold 50 is omitted.

  The inner horizontal scaffold 40 is installed on the gantry main body 6a of the pedestal 6 and includes a support frame scaffold 41, and a lower inner scaffold 42 and an upper inner scaffold 43 attached to the support frame scaffold 41. Have been. The support frame scaffold 41 is the same as that used for the inside vertical scaffold 60 shown in FIG. 10, and is used for both the inside vertical scaffold 60 and the inside horizontal scaffold 40 shown in FIG.

  The lower inner scaffold 42 and the upper inner scaffold 43 are attached to the support frame scaffold 41 at predetermined positions in the height direction. The lower-stage inner scaffold 42 and the upper-stage inner scaffold 43 have the same configuration in the present embodiment. As shown by an arrow in FIG. It is an open / close scaffold that opens and closes.

  That is, the lower inner scaffold 42 and the upper inner scaffold 43 are attached to a horizontal pipe (not shown) of the support frame scaffold 41, and a pair of large-diameter short pipes (not shown) serving as bearings. A small-diameter long pipe (not shown), which is rotatably and movably inserted in the longitudinal direction between these short pipes and serves as a held (held) rotation axis, is provided on the long pipe. And a rectangular plate 44 fixed integrally. Since the pair of short pipes are attached to the horizontal pipes by the clamps, the long pipe is rotatable, that is, functions as a rotation axis.

  As a result, the plate body 44 fixed to the long pipe is openably and closably opened above the inner side opposite to the inner tank side plate 7. Chains 46 are connected to both sides of the plate body 44, respectively. The chains 46 are connected to the support frame scaffolding 41 obliquely above the inside, so that the plate body 44 is held in a horizontal posture. I have. That is, it can be opened and closed only on the inner upper side without rotating downward. In addition, the plate body 44 is formed of a metal mesh plate such as expanded metal for weight reduction, similarly to the steel plate of the support frame scaffold 41.

  Under such a configuration, the lower inner scaffold 42 and the upper inner scaffold 43 are easily attached to and fixed to the support frame scaffold 41. Further, equipment such as a welding device and an inspection device can be installed on each plate 44, so that work can be performed on each plate 44. Specifically, welding of the next inner tank side plate 7 to the raised inner tank side plate 7 is mainly performed on the lower inner scaffold 42, and upper and lower inner tank side plates 7 are welded on the upper inner scaffold 43. Inspection of the welding state between the two is mainly performed.

  Further, such a lower inner scaffold 42 and an upper inner scaffold 43 are used for lifting and lowering equipment such as devices by using a hanging tool or the like suspended from the upper knuckle inner rail 13 or for welding the inner tank side plate after welding. At the time of raising, for example, by simply opening the plate body 44 serving as the opening / closing scaffold to the inside upper side and opening the inner tank side plate 7 side, the lower inner scaffold 42 and the upper inner scaffold 43 do not interfere with equipment and accessories and accessories. You can do so. When the plate body 44 is opened upward and the inner tank side plate 7 side is opened, for example, the chain 46 is fixed with a fixing device (not shown), or the plate body 44 is directly attached to the support frame scaffold 41 with a rope or the like. By fixing, the plate body 44 is fixed in an open state.

  Here, regarding the attachment position (attachment height) of the lower inner scaffold 42 and the upper inner scaffold 43 to the support frame scaffold 41, the lower inner scaffold 42 is attached to the next inner tank side plate 7 with respect to the raised inner tank side plate 7. It is preferable to set the position (height) where welding can be easily performed, and it is preferable that the upper inner scaffold 43 be a position (height) where inspection of the welding state between the upper and lower inner tank side plates 7 can be easily performed. Specifically, it is preferable to dispose it at a position about 1.2 m lower than the upper end of the inner tank side plate 7 which is upright or suspended and has a height of about 4 m.

  That is, the plate body 44 on which the worker for performing the welding or the inspection after the welding stands is positioned at a position lower than the seam 7a (horizontal seam) between the upper and lower inner tank side plates 7 by about 1.2 m. This is preferable because the position of the operator's hand and eyes can be easily adjusted to the position of the joint 7a. Therefore, the lower inner scaffold 42 and the upper inner scaffold 43 of the present embodiment are arranged at positions where the respective plate bodies 44 are lower than the upper end of the inner tank side plate 7 which is arranged to face by about 1.2 m. At this time, the lower inner scaffold 42 and the upper inner scaffold 43 of the present embodiment can be fixed to the support frame scaffold 41 by simply attaching the short pipe to the horizontal pipe by the clamp as described above. It can be easily adjusted to a desired height.

  By forming the inner horizontal scaffold 40 having such a configuration on the gantry body 6a, welding (horizontal seam) between the inner tank side plates 7 arranged vertically and work such as inspection related to such welding are mainly performed. It can be done easily. That is, the joint 7a between the inner tank side plates 7 arranged vertically can be welded by the lower inner scaffold 42 of the support frame scaffold 41, and the welding of the seam 7a can be inspected by the upper inner scaffold 43.

  The outer lateral scaffold 50 is installed outside the inner tank side plate 7, that is, between the side wall 3 of the outer tank and the inner tank side plate 7 and above the gantry main body 6 a of the pedestal 6. Is attached to and held by the frame member 48 fixed to the inner surface of the side wall 3. The frame member 48 is formed of a plurality of angle members as described above, and the frame member 48 formed of such a plurality of angle members is attached to the frame member 48 formed of the plurality of angle members similarly to the outer vertical scaffold 70 shown in FIG. As shown in FIG. 7, an outer lateral scaffold 50 is also attached and held.

  The outer horizontal scaffold 50 includes a lower outer scaffold 51 attached below the frame member 48 and an upper outer scaffold 52 attached above. The lower outer scaffold 51 is arranged at a height position corresponding to the lower inner scaffold 42 of the inner horizontal scaffold 40, and is arranged in a circumferential direction with respect to the frame material 48 made of an angle material and installed in the circumferential direction of the side wall 3. A holding member 49 attached in the (horizontal direction) and a rectangular plate 53 integrally formed with a rotation shaft (not shown) rotatably held by the holding member 49 are provided. With such a configuration, the plate body 53 can be opened and closed outward and downward (below the side wall 3) by the rotation of the rotation shaft held by the holding member 49. The plate body 53 is also formed of a metal mesh plate such as expanded metal for weight reduction, like the plate body 44 of the inside horizontal scaffold 40.

  The plate 53 is rotatably connected to the bottoms on both sides on the front end side (the inner tank side plate 7 side), without doing so. Numeral 54 is a bar-shaped hook (a hook bar) whose lower end is detachably fixed to the frame member 48 by bolting or the like, and whose upper end is rotatable to the plate 53 by a hinge or the like. Are linked. With such a configuration, the plate 53 is supported by the support 54 without maintaining the lower end of the plate 54 as shown by a solid line in FIG. It has become so. Thus, the load of the worker or the equipment can be supported by the plate 53, and the plate 53 functions as a work scaffold.

  In this state, the fixing of the lower end portion of the frame 54 to the frame member 48 is released, so that the plate body 53 is moved downward (downward on the side wall 3 side) as shown by a two-dot chain line in FIG. To open and open between the side wall 3 and the inner tank side plate 7. Also, without doing so, 54 also hangs down along the inner surface of the side wall 3 together with the plate body 53 to open the space between the side wall 3 and the inner tank side plate 7.

  Here, the height of the holding member 49 in the lower outer scaffold 51 is at a position higher than the upper surface of the gantry main body 6a by about 2.8 m (a height obtained by subtracting 1.2 m from the height of the inner tank side plate 7 of 4 m). Accordingly, since the lower end of the 54 can be reached without being reached by the operator from reaching the top of the gantry body 6a, the fixing of the 54 to the frame member 48 is released, and the 54 is lowered without doing so. The body 53 can be opened. Therefore, there is a relatively large space inside the inner tank side plate 7, and the inner tank side plate 7 and the outer tank have only a gap of about 1100 mm compared to the inner horizontal scaffold 40 that can open and close the plate body 44 from the support frame scaffold 41. The plate body 53 can be easily opened and closed also on the outer horizontal scaffold 50 between the side walls 3. Note that a large number of the plate bodies 53 are continuously provided along the circumferential direction of the side wall 3. Therefore, when opening and closing the plate body 53, the operator and the equipment on the plate body 53 are moved to the adjacent plate body 53, etc., so that the opening and closing of the plate body 53 can be performed smoothly. it can.

  The lower outer scaffold 51 having such a configuration is formed and arranged such that the height position of the plate body 53 in the horizontal state is substantially the same as the height position of the lower inner scaffold 42 in the horizontal state of the plate body 44. Have been. Therefore, the next inner tank side plate 7 can be easily welded to the raised inner tank side plate 7 on the plate 53 of the lower outer scaffold 51. In the case where the equipment is lifted and lowered by the hooks 12 suspended from the gondola rail 11, the plate 53 is lowered downward (downward on the side wall 3 side) by removing 54 instead of doing so as described above. By opening the tank side plate 7 side, the plate body 53 can be prevented from interfering with the elevating of the equipment and the like. Further, when assembling the outer vertical scaffold 70 as shown in FIG. 10 in order to perform the work related to the vertical seam welding, the plate 53 is removed downward by simply removing the scaffold 54 (below the side wall 3). The lower vertical scaffold 70 can be assembled without removing the lower outer scaffold 51.

  The upper outer scaffold 52 is arranged at a height corresponding to the upper inner scaffold 43 of the inner horizontal scaffold 40 and attached to the frame member 48, and supports the plate 55 and the plate 55 in a horizontal state. And a supporting member 56. The plate body 55 has a rear end fixed to the frame member 48 by bolting or the like, and a substantially half of the front side (substantially half of the inner tank side plate 7 side) is formed to be rotatable downward with respect to the substantially half of the rear side. Have been.

  That is, the front plate 55a disposed on the front side is rotatably connected to the rear plate 55b disposed on the rear side via a rotation shaft (not shown) or by a hinge or the like. A well-known lock mechanism (not shown) such as a stopper that disables downward rotation of the front plate 55a is provided between the front plate 55a and the rear plate 55b. In the example shown in FIG. 11, the front plate 55a is formed to be rotatable downward (outward and downward) with respect to the rear plate 55b, but the front plate 55a is rotated upward (outward and upward) with respect to the rear plate 55b. It may be movably formed. Also in this case, a stopper that prevents the front plate 55a from rotating downward is used as the lock mechanism. Further, the front plate 55a and the rear plate 55b are also formed of a metal mesh plate such as expanded metal for weight reduction, similarly to the plate body 44 of the inside horizontal scaffold 40.

  The support member 56 has a rod shape or a thin plate shape. The lower end is fixed to the frame member 48 by bolting or the like, and the upper end is fixed to the front end of the rear plate 55b of the plate 55 by bolting or the like. . Thus, the support member 56 supports the rear plate 55b without interfering with the rotation of the front plate 55a. Therefore, as shown by the solid line in FIG. 11, during the operation, the front plate 55a is kept horizontal together with the rear plate 55b. Therefore, the load of an operator or equipment can be supported by the plate 55, and the plate 55 functions as a work scaffold.

  The upper outer scaffold 52 having such a configuration is formed and arranged so that the height position of the plate 55 in the horizontal state is substantially the same as the height position of the plate body 44 of the upper inner scaffold 43 in the horizontal state. Have been. Therefore, on the plate 55 of the upper outer scaffold 52, the inspection of the welding of the joint 7a between the upper and lower inner tank side plates 7 can be easily performed.

  Further, in the case where the equipment is lifted and lowered by the hook 12 suspended from the gondola rail 11, the front plate 55a is rotated downward as shown by a two-dot chain line in FIG. The inner tank side plate 7 side can be opened so as not to interfere. At this time, since only the front plate 55a is opened in the plate body 55, the operator can operate the front plate 55a from above the rear plate 55b to open it.

  When opening and closing the front plate 55a, for example, a rope or the like is connected to the front end of the front plate 55a in advance, and the rope is operated from above the rear plate 55b to easily open and close the front plate 55a. It can be carried out. Note that a large number of plate bodies 55 are also provided continuously along the circumferential direction of the side wall 3. Therefore, when the front plate 55a is opened and closed, a large device or the like on the plate 55 is moved to an adjacent plate 55 or the like before the opening and closing of the front plate 55a, so that the front plate 55a can be smoothly opened and closed.

  As shown in FIG. 9, when the next inner tank side plate 7 is carried into the space on the pedestal 6, the plurality of inner tank side plates 7 are connected in advance laterally outside the outer tank side wall 3. You may keep it. Then, this is taken into the side wall 3 and formed into an annular shape, and then the inner tank side plates 7 arranged vertically are welded to each other. As described above, by performing the plurality of inner tank side plates 7 outside the side wall 3 where the working space is less limited, the welding operation is facilitated and the inner tank can be efficiently assembled.

  Here, accessories such as a stiffener 57 and a key nut 58 are provided on the inner surface of the inner tank side plate 7 as shown in FIG. 11, and a key nut 58 and the like are also provided on the outer surface of the inner tank side plate 7. . Therefore, when the inner tank side plate 7 is raised by the jack-up device 19, such accessories interfere with the plate member 44 of the inner horizontal scaffold 40, the plate member 55 of the outer horizontal scaffold 50, and the plate member 53. There is a risk that it will.

  However, the plate body 44 of the inner horizontal scaffold 40 is formed so as to be rotatable inward and upward as indicated by an arrow in FIG. 11, and is configured to open and close the inner tank side plate 7 side. Therefore, by rotating the plate body 44 when the inner tank side plate 7 is raised, such interference can be easily and reliably prevented. In addition, the plate 55 of the outer lateral scaffold 50 also has a front plate 55a formed so as to be rotatable outward and downward, and is thus configured to open and close the inner tank side plate 7 side. Can be easily and reliably prevented. Further, the plate body 53 of the outer lateral scaffold 50 is also formed so as to be rotatable outward and downward, so that the inner tank side plate 7 side is configured to be openably and closably opened. And it can be prevented reliably.

  When welding a vertical seam between the inner tank side plates 7 adjacent to each other in the horizontal direction, the inside vertical scaffold 60 and the outside vertical scaffold 70 shown in FIG. 10 are assembled and used. Since the vertical seam is located at a predetermined interval in the circumferential direction of the side wall 3 of the outer tub, it is necessary to move the welding device and the inspection device in the circumferential direction. At this time, it is difficult to move the welding device by manual power, especially when the welding device is an automatic welding machine that is heavy, so that the gondola rail 11 and the knuckle inner rail 13 shown in FIG. Move.

  That is, inside the inner tank side plate 7, the automatic welding machine is suspended using the knuckle inner rail 13 and moved along the knuckle inner rail 13 to move the automatic welding machine to a desired position. On the outside of the inner tank side plate 7, the automatic welding machine is suspended by the hook 12 of the gondola rail 11 and moved along the gondola rail 11 to move the automatic welding machine to a desired position. At this time, since the inside vertical scaffold 60 and the outside vertical scaffold 70 have a simple configuration, for example, only the scaffold plate 62 (72) is removed so as not to interfere with the movement of the automatic welding machine.

  As shown in FIG. 9, when the jack-up is performed by the jack-up device 19, the jack-up device 19 projects from the upper end of the jack-up rod 20 above the suspension base 18. 5 will interfere. Therefore, while the inner tank side plates 7 are being welded to each other, the portions of the plurality of rods 20b constituting the jack-up rods 20 protruding above the suspension base 18 are removed. Then, it is lowered on the inner tank roof 14 by a davit (not shown) which has been installed on the top of the jack-up device scaffold 17 in advance. The removal of the rod 20b is performed using the jack-up device scaffold 17. Also, the upper side of the jack-up device scaffold 17 is sequentially removed by the hanging balance 21 so as not to be interfered by the suspension scaffold 5.

  Next, the tank constituent member Y is raised by approximately one step of the inner tank side plate 7 by the jack-up device 19, and the next inner tank side plate 7 is further loaded into a space formed below the inner tank side plate 7; In the same manner as the case of the inner tank side plate 7 of the eighth stage (# 8), the inner tank side plate 7 of the seventh stage (# 7) is attached as shown in FIG. At this time, the rod 20b protruding upward from the suspension base 18 is removed, and the rod 20b is lowered on the inner tank roof 14 by the suspension balance 21.

  When the inner tank side plates 7 from the ninth stage (# 9) to the seventh stage (# 7) are attached in this way, the suspension scaffold 5 on the inner peripheral surface side of the side wall 3 is removed as shown in FIG. That is, since a sufficient time has passed by this time, the outer tank side wall 3 has been completed up to the ninth step (# 9), which is the uppermost step, so that the formwork and the like can be removed. Therefore, the inner peripheral surface side of the side wall 3 can be removed. Note that the outer peripheral surface side of the side wall 3 is not removed and is left as it is in a later step.

Next, in order to change the jack-up device 19, as shown in FIG. 13, a second suspension base 25 is installed on the top of the side wall 3 of the outer tub. Also, the tank component Y (including the inner tank side plate 7 at the 8th and 7th stages) is once dropped down onto the stand 6 with legs.
Subsequently, the jack-up rod 20 of the jack-up device 19 shown in FIG. 7 is temporarily removed from the suspended plate 10b of the knuckle support 10 using a suspension balance 21, a crane, or the like. Further, the jack body 20a of the jack-up device 19 is removed from the suspension gantry 18. Thereby, the jack-up device 19 is removed from between the side wall 3 of the outer tub and the knuckle plate 9. Further, the suspension base 18 is removed from the side wall 3.

  Then, the jack body 20a of the jack-up device 19 is attached to the second suspension base 25 shown in FIG. At this time, the jack-up rod 20 was removed from the upper side so as not to be interfered with by the suspension scaffold 5 and lowered onto the inner tank roof 14. However, the suspension scaffold on the inner peripheral surface side of the side wall 3 was used. Since the jack-up rod 20 can be freely extended by removing the rod 5, the rod 20b lowered on the inner tank roof 14 is attached to the jack-up rod 20 again, and the jack-up rod 20 is lengthened. In this embodiment, as shown in FIG. 13, in order to suspend from the ninth stage (# 9), which is the uppermost stage of the side wall 3 of the outer tub, to the fifth stage (# 5), a spare rod 20b separately prepared in advance is used. Add and adjust the jack-up rod 20 to the desired length.

  After adjusting the jack-up rod 20 to a desired length in this manner, the lower end side is inserted into the notch of the suspended plate 10b of the knuckle support 10 again. Then, the lower end of the jack-up rod 20 is fixed to the suspended plate 10b by the nut 19a. Thereby, the jack-up device 19 can be changed. When the rearrangement of the jack-up device 19 is completed in this way, the jack-up device scaffold 17 is removed as shown in FIG.

Next, as shown in FIG. 14, the knuckle plate 9 is lifted by the jack-up device 19, and the tank component Y is raised by almost one step of the inner tank side plate 7.
Subsequently, the next inner tank side plate 7 is further carried into the space formed below the inner tank side plate 7, and the inner tank side plates 7 of the eighth stage (# 8) and the seventh stage (# 7) described above are hereinafter described. In the same manner as in the above case, the inner tank side plate 7 of the sixth stage (# 6) is attached as shown in FIG.

Next, the outer tank roof 26 is mounted on the inner tank roof 14. The outer tank roof 26 is attached by attaching a large number of connecting members (not shown) made of channel steel or the like on the inner tank roof 14 and attaching the outer tank roof 26 to these connecting members.
Also, the operation of attaching a side liner (not shown) to the inner peripheral surface of the side wall 3 of the outer tank is started.

Hereinafter, the tank component Y is lifted by the jack-up device 19, the next inner tank side plate 7 is loaded below the inner tank side plate 7 (tank component Y), and the tank component Y (inside) of the loaded inner tank side plate 7 is loaded. The attachment to the tank side plate 7) is sequentially repeated, and the inner tank side plate 7 is attached to the lowermost first stage (# 1) as shown in FIG. Thereby, the side wall of the inner tank is completed.
At the time of mounting the inner tank side plate 7 of each stage, that is, while the tank constituent member Y is being lifted and the space below the tank constituent member Y is used as a space, various materials 27 are separated from the inner tank side plate 7 by the side wall. 3 is loaded on the basic plate 1. A work scaffold 28 is assembled on the outer tank roof 26.

Next, as shown in FIG. 17, the pedestal 6 is removed, so that the space below the tank component Y becomes a space. Then, the tank component Y is jacked down by the jack-up device 19, and an outer peripheral end of a roof bone (not shown) of the outer tub roof 26 is embedded in a top inner peripheral surface of the side wall 3 of the outer tub. And fix them.
Subsequently, a connecting member (not shown) connecting the outer tank roof 26 and the inner tank roof 14 is removed, and the connection between them is released.

Next, as shown in FIG. 18, the tank component Y is jacked down again by the jack-up device 19, and the lowermost lower end of the inner tank side plate 7 is lowered onto the annular portion 16. Then, the lower end of the lowermost step of the inner tank side plate 7 is attached to the inner tank anchor strap 2 installed on the base plate 1.
Next, the knuckle support 10 is removed from the knuckle plate 9.

Thereafter, tension work is performed on the side wall 3 of the outer tank. Further, a polyurethane foam (PUF), which is a thermal resistance reducing material, is sprayed on a side liner (not shown) attached to the inner peripheral surface of the side wall 3 of the outer tank. Further, the jack-up device 19, the second suspension frame 25, and the like are also removed. Then, after the construction port 4 is closed and a pump barrel (not shown) is installed, the structure is filled with water and a pressure resistance and air tightness test is performed.
Finally, a cooling material (not shown) such as perlite is filled between the inner tank and the outer tank to perform a cooling operation between the inner and outer tanks, and further, a cylindrical tank 100 is constructed through painting work and pipe cooling work. I do.

  According to the method for constructing a cylindrical tank of this embodiment, the inner tank side plate 7 is supported between the inner tank side plate 7 supported on the pedestal 6, the outer tank side wall 3 opposed thereto, and the support frame scaffold 41. 7 is formed by the vertical scaffolds (the inner vertical scaffold 60 and the outer vertical scaffold 70) having the frame body 61 (71) and the scaffold plate 62 (72). For example, when welding the vertical seam of the inner tank side plate 7, the frame 61 (71) is simply installed at a desired position, and the scaffold plate 62 (72) is bridged over the frame 61 (71). The inner vertical scaffold 60 and the outer vertical scaffold 70 can be easily assembled on site. Therefore, the vertical seam of the inner tank side plate 7 can be easily welded or inspected after welding by using such a vertical scaffold. Further, the scaffold can be easily reassembled in accordance with the position of the vertical seam. Further, since the frame body 61 (71) and the like are not directly attached to the inner tank side plate 7, it is not affected even when the inner tank side plate 7 is jacked up or jacked down. Therefore, it is not necessary to reassemble the scaffold. Therefore, according to the construction method using such a vertical scaffold, it is possible to shorten the construction period.

  In addition, since the inner vertical scaffold 60 and the outer vertical scaffold 70 are provided with the side plate abutting members 64 (74) extending from the frame body 61 (71) so as to extend and contract and abut against the inner tank side plate 7, the inner vertical scaffold is provided. By fixing the side plate butting member 64 (74) to the inner tank side plate 7 at the time of working on the outer vertical scaffold 60 and the outer vertical scaffold 70, the inner vertical scaffold 60 and the outer vertical scaffold 70 are fixed and shaken. Can be eliminated. Therefore, the work on the inside vertical scaffold 60 and the outside vertical scaffold 70 can be stably performed.

  Also, the outer vertical scaffold 70 is provided with the outer tank abutting member 75 extending from the frame body 71 so as to be extendable and contractable and abutting against the side wall 3 of the outer tank. By abutting the member 75 against the side wall 3 of the outer tub, the outer vertical scaffold 70 can be fixed and its swing can be eliminated. Therefore, work on the outer vertical scaffold 70 can be performed stably.

  As described above, the preferred embodiments of the present invention have been described with reference to the drawings, but the present invention is not limited to the embodiments. The shapes, combinations, and the like of the respective constituent members shown in the above-described embodiments are merely examples, and can be variously changed based on design requirements and the like without departing from the gist of the present invention.

  For example, in the above-described embodiment, a step of installing a plurality of pedestal mounts 6 (stands) for supporting the inner tank side plate 7 on the inner peripheral surface side of the side wall 3 is provided as a pre-process of assembling the inner tank. Is not limited to this. That is, by removing the step of providing the base 6 with legs on the base plate 1 (previous step), the inner tank side plate 7 can be formed by the base plate 1, more precisely, by the bottom liner provided on the upper surface of the base plate 1. May be supported.

  3 ... side wall (side wall of outer tank), 6 ... stand with legs (stand), 7 ... inner tank side plate, 7a ... seam, 41 ... support frame scaffold (support frame), 48 ... frame material, 60 ... inner vertical scaffold Reference numeral 61, frame body, 62, scaffold plate, 63, clamp, 64, side plate butting member, 70, outer vertical scaffold, 71, frame body, 72, scaffold plate, 73, mounting member, 74, side plate butting member , 75… Outer tank abutment member

Claims (3)

A method for constructing a cylindrical tank having an inner tank and an outer tank,
Installing a gantry supporting the inner tub side plate inside the outer tub, and raising the inner tub side plate on the gantry, and the next inner tub side plate below the raised inner tub side plate And the step of assembling the inner tank by alternately repeating
A scaffold for performing an operation on the inner tank side plate, a frame that is detachably attached to the support frame or the outer tank that is located on the gantry opposite the outer tank with respect to the inner tank side plate, and the frame. By using a vertical scaffold having a scaffold plate detachably attached to the body, the scaffold is formed between the inner tank side plate and the outer tank or between the inner tank side plate and the support frame. How to build a cylindrical tank. The method for constructing a cylindrical tank according to claim 1 , wherein the vertical scaffold has a side plate abutting member extending from the frame so as to extend and contract and abut against the inner tank side plate . The vertical scaffolding between the inner tank side plate and the outer tank has an outer tank abutting member that extends and contracts from the frame body and abuts on the outer tank. The construction method of the cylindrical tank described in the above.

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