JP2018104915A - Tank demolition method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tank demolition method for demolishing a tank without using a large-scale facility.SOLUTION: A tank demolition method is for demolishing a tank having a bottom plate and a side wall extending upward from the bottom plate. A first region and a second region that are laid out alternately in a circumferential direction are set at a bottom edge part of the side wall. A deforming guide part is installed between a foundation part including the bottom plate and the first region, the deforming guide part having a guiding surface for guiding the first region in an out-of-plane direction of a wall surface of the side wall and deforming the first region, when the side wall has been lowered. The demolition method includes a slit formation step for forming a slit in the side wall along a boundary line between the first region and the second region, a bottom edge part removal step for removing the second region at the bottom edge part, and a lowering step for lowering the side wall while the foundation part and the side wall are separated. In the lowering step, the first region of the lowered side wall is guided by the guiding surface of the deforming guide part and is deformed.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a tank dismantling method.

  Patent Document 1 describes a tank dismantling method for disassembling a tank side plate. In this tank dismantling method, a plurality of locations at the lower end of the tank side plate are cut into a gate shape and removed to form a notch in the tank side plate, and a jack is placed in the notch to support the tank roof and tank side plate. Jack up to get the initial state. In this state, the remaining part of the tank side plate is cut to a position higher than the upper end of the notch and removed, so that the part supported by the jack becomes a new remaining part, and after the jack is down, the space between the new remaining parts Place another jack on the Another jack arranged between the new remaining portions is jacked up so that the tank roof and the tank side plate can be supported, and thereafter, the work procedure from the initial state is repeated to disassemble the tank side plate.

JP-A-9-324544

  In the tank dismantling method as described above, a jack is disposed in the notch portion in the initial state, and when the portion supported by the jack is a new remaining portion, the jack is also disposed between the new remaining portions. Therefore, a large number of jacks are used, and the entire apparatus used for work is large. In the initial state, the tank roof and the tank side plate are supported by a part of the many jacks, and when the part supported by the jacks in the initial state is a new remaining part, The remainder supports the tank roof and tank side plates. Therefore, in order to stably support the load on the tank roof and the tank side plate, each jack is required to have sufficient capacity so that the load can be supported by only a part of the jacks. Therefore, the entire apparatus becomes even larger.

  Then, an object of this invention is to provide the tank disassembly method which can disassemble a tank, without using a large-scale apparatus.

  A tank disassembling method according to the present invention is a tank disassembling method for disassembling a tank including a bottom plate and a side wall extending upward from the bottom plate, and a first disposition alternately arranged in a circumferential direction at a lower end portion of the side wall. An area and a second area are set, and when the side wall is lowered between the first area and the base portion, a guide surface that guides the first area in the out-of-plane direction of the wall surface and curves and deforms the first area. A deformation guide portion having a cutting edge forming step for forming a cut in the side wall along the boundary line between the first region and the second region, a lower end portion removing step for removing the second region at the lower end portion, and a foundation A lowering step of lowering the side wall in a state where the portion and the side wall are separated from each other. In the lowering step, the first region of the lowering side wall is guided by the guide surface of the deformation guide portion and deformed.

  According to the tank disassembling method according to the present invention, the deformation guide portion is installed between the first region and the base portion. The deformation guide portion has a guide surface that guides and deforms the first region in the out-of-plane direction of the wall surface of the side wall when the side wall is lowered. When a cut is formed in the side wall along the boundary line between the first region and the second region, the lower end of the second region is removed and the side wall is lowered, the first region is guided and deformed in the out-of-plane direction, Two areas descend towards the base. At this time, the side wall descends while receiving a resistance force resulting from the deformation of the first region. As a result, for example, the tank can be disassembled with a simple structure compared to the case where the side wall is lowered while the side wall load is supported by a jack, and the tank can be disassembled without using a large-scale device. It becomes possible.

  In the tank dismantling method according to the present invention, the lower end portion removing step may be executed in a state where the second region of the descending side wall is in contact with the base portion. In this case, the second region of the side wall can be removed in a state where the second region of the side wall is in contact with the base and the side wall is supported by the base.

  The tank disassembly method according to the present invention may further include a notch forming step of forming a notch for removing the first region at the lower end portion and installing the deformation guide portion. In this case, it is possible to secure a place for installing the deformation guide portion by the notch, and in the lower end portion removing step, the second region which is a portion other than the notch is removed from the lower end portion of the side wall. be able to. Therefore, the dismantling operation of the tank can be performed with a simpler configuration.

  In the tank dismantling method according to the present invention, in the state where the deformation guide portion is installed, the notch forming step of extending the notch and the lowering step may be repeatedly executed. In the descent process, the side wall descends according to the amount of cut formed in the cut formation process. Therefore, the side wall can be lowered stepwise with respect to the range in which the lower end portion is removed by forming the cut to be extended. Therefore, the side wall can be slowly lowered as compared with the case where the cut is formed at a time in the range where the lower end portion is removed.

  ADVANTAGE OF THE INVENTION According to this invention, the tank disassembly method which can disassemble a tank, without using a big apparatus can be provided.

FIG. 1 is a side view showing a tank to which a tank disassembly method according to an embodiment of the present invention is applied. FIG. 2 is a diagram illustrating each process according to the present embodiment. FIG. 3 is a diagram showing each process according to the present embodiment. FIG. 4 is a diagram showing each process according to the present embodiment. FIG. 5 is a diagram illustrating each process according to the present embodiment. FIG. 6 is a diagram illustrating each process according to the present embodiment. FIG. 7 is a diagram illustrating each process according to the present embodiment. FIG. 8 is an enlarged cross-sectional view of a region VIII shown in FIG. 9 is a cross-sectional view taken along the line IX-IX shown in FIG.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the part which is the same or it corresponds in each figure, and the overlapping description is abbreviate | omitted.

  FIG. 1 is a partial cross-sectional side view showing a tank to which a tank disassembly method according to an embodiment of the present invention is applied. The tank 1 is, for example, an above-ground LNG tank that stores LNG (Liquefied Natural Gas). The tank 1 is a large tank having a structure of, for example, a capacity of 25,000 KL to 14.0 million KL, an inner diameter of 36.0 m to 79.4 m, and a liquid depth of 24.3 m to 30.3 m. However, the tank is not limited to a ground type LNG tank. The tank dismantling method according to the present embodiment can be applied to dismantling a tank that stores petroleum, LPG (Liquefied petroleum Gas), or the like.

  As shown in FIG. 1, the tank 1 is provided on a concrete foundation slab 2. The tank 1 is supported by a ground G and a plurality of piles 3 whose tips are embedded in the ground G via a foundation slab 2. The tank 1 includes a bottom plate 4, side walls 5, and a roof 6.

  The bottom plate 4 and the side wall 5 form a storage space S for storing LNG. The bottom plate 4 and the side wall 5 are made of, for example, a steel plate. The bottom plate 4 is provided along the upper surface of the basic slab 2. The bottom plate 4 is formed in a circular shape in plan view. The side wall 5 has a cylindrical shape with a vertical cylinder axis, and extends upward from the bottom plate 4. The lower end 5a of the side wall 5 is joined to the bottom plate 4 by welding or the like, for example. An opening that opens upward is formed at the upper end 5 b of the side wall 5. The opening of the upper end 5 b of the side wall 5 is closed by a dome-shaped roof 6 that covers the storage space S.

  A tank disassembly method for disassembling the tank 1 having the above structure will be described. In the following description, the terms “radial direction”, “circumferential direction”, and the like simply mean the radial direction and the circumferential direction of the cylindrical side wall 5. 2-7 is a side view which shows each process which concerns on 1st Embodiment. The tank disassembly method according to the present embodiment includes a dividing step, a guide portion installing step, a notch forming step, a notch forming step, a lower end removing step, and a descending step.

  In the tank disassembly method according to the present embodiment, the first region R1 and the second region R2 that are alternately arranged in the circumferential direction are set in the lower end portion 5a of the side wall 5. The first region R1 and the second region R2 are set over the entire circumference in the circumferential direction. As an example, the length in the circumferential direction of the first region R1 is 2 m, and the length in the circumferential direction of the second region R2 is 8 m.

<Division process>
First, as shown in FIG. 2, the side wall 5 is separated from the bottom plate 4. Specifically, the joining location of the lower end portion 5a of the side wall 5 joined to the bottom plate 4 is cut by, for example, gas cutting. The side wall 5 is cut off from the bottom plate 4 over the entire periphery of the lower end 5a. Hereinafter, the part including the ground G, the foundation slab 2, the pile 3, and the bottom plate 4 divided from the side wall 5 is referred to as a foundation part 7.

<Cut forming process>
Subsequently, a notch 51 for installing the deformation guide portion on the side wall 5 is formed. Specifically, the plurality of first regions R1 at the lower end portion 5a of the side wall 5 are removed, and a plurality of notches 51 are formed. That is, a plurality of notches 51 are arranged on the side wall 5 at a constant interval (here, 10 m) over the entire circumference of the lower end portion 5a. The notch 51 is formed by cutting the side wall 5 by gas cutting, for example. The cutout 51 is formed so as to have an upper edge portion 51s that is horizontal in at least the circumferential direction. The notch 51 has a rectangular shape, for example. The height of the notch 51 is, for example, 1.5 m. However, the size and shape of the notch 51 may be arbitrarily changed.

<Guide part installation process>
Next, as shown in FIG. 3, the deformation guide portion 8 is inserted between the upper edge portion 51 s of the notch 51 and the base portion 7. The deformation guide portion 8 is inserted into the notch 51 from the inside of the tank 1 toward the outside of the tank 1 and is installed in the notch 51. Specifically, the deformation guide portion 8 is pushed radially outward from the center of the tank 1 until a later-described guide surface 83s contacts the upper edge portion 51s of the notch 51, and the deformation guide portion 8 is The state is sandwiched between the portion 51 s and the upper surface 4 s of the bottom plate 4. In this state, the deformation guide portion 8 is joined (fixed) to the bottom plate 4 by welding or the like, for example. The deformation guide portion 8 is installed in all of the plurality of notches 51. The detailed configuration of the deformation guide portion 8 will be described later.

<Lower end removal process>
Next, as shown in FIG. 4, the second region R2 at the lower end 5a of the side wall 5 is removed. Specifically, the second region R2 at the height position of the notch 51 (here, the height position of 1.5 m) from the lower end edge of the side wall 5 is cut along the cutting line L1 (see FIG. 3) by gas cutting, for example. ) Along the circumferential direction. Further, in order to prevent the side wall 5 from being largely inclined during the work, the two second regions R2 facing each other in the radial direction among the plurality of second regions R2 at the lower end portion 5a of the side wall 5 are each The two second regions R2 are cut simultaneously or alternately. Then, the cut portion of the second region R2 is removed. Here, the plurality of second regions R2 set over the entire circumference of the lower end portion 5a of the side wall 5 are all removed.

<Incision forming process>
Further, a cut 52 is formed along the boundary line L2 between the first region R1 and the second region R2. Specifically, the lower end portion 5a of the side wall 5 is cut by, for example, gas cutting so as to extend upward from the side edge portion 51t of the notch 51. The length of the cut 52 is, for example, 30 cm.

  In addition, any process may be performed previously as said lower end part removal process and a notch formation process. Or both processes of a lower end part removal process and a notch formation process may be performed in parallel. Moreover, the parting process should just be performed before the process of both a lower end part removal process and a notch formation process is completed. The side wall 5 and the bottom plate 4 may be separated from each other in the next descending step.

<Descent process>
Next, as shown in FIG. 5, the side wall 5 is lowered. Here, the side wall 5 is lowered by its own weight. The side wall 5 is in a state of being separated from the bottom plate 4 in the dividing step. And the lower end part 5a is removed, and it will be in the state which floated from the baseplate 4 by the deformation | transformation guide part 8 in 1st area | region R1 in the lower end part 5a. In this state, since the cut 52 is formed along the boundary line L2 between the first region R1 and the second region R2, the first region R1 descends while being deformed by the deformation guide portion 8 due to the weight of the side wall 5. . The first region R <b> 1 is guided by the guide surface 83 s of the deformation guide portion 8 radially outward (outside of the outer wall surface 5 s of the side wall 5) to bend and deform. The side wall 5 descends while receiving an upward resistance force from the deformation guide portion 8 due to the deformation of the first region R1. Further, the second region R2 descends substantially vertically downward toward the bottom plate 4. Since the descending side wall 5 receives the upward resistance force from the deformation guide portion 8 in the first region R1 as described above, the descending speed is suppressed and the entire side wall 5 gradually descends.

  When the side wall 5 descends and the resistance force received from the deformation guide portion 8 in the first region R1 increases, the weight of the side wall 5 and the resistance force received by the side wall 5 balance, and the side wall 5 descends. Stops. Therefore, when the descent of the side wall 5 stops or before the descent of the side wall 5 stops, a cut forming process is executed to newly form the cut 52. The new cut 52 is formed so as to extend the existing cut 52 upward. By extending the cuts 52 as described above, the resistance force received by the side wall 5 from the deformation guide portion 8 is reduced, and the descent (lowering process) of the side wall 5 is continued. In this way, the side wall 5 is lowered by repeatedly executing the notch forming step and the lowering step. As described above, before the descent of the side wall 5 stops, the notch 52 may be extended to perform the descent process continuously. Alternatively, the incision forming step may be performed from a state where the weight and the resistance force are balanced and the lowering of the side wall 5 is stopped.

  As the descent of the side wall 5 continues, as shown in FIG. 6, when the second region R2 at the lower end 5a of the side wall 5 lands on the bottom plate 4, the descent of the side wall 5 stops. Therefore, as shown in FIG. 7, the lower end portion removing step is performed again, and the second region R2 is cut and removed in the circumferential direction, thereby continuing the descent of the side wall 5. Thus, the side wall 5 is gradually removed from the lower end while the side wall 5 is lowered by repeatedly executing the lower end portion removing step and the lowering step. Here, the lower end portion removing step is performed in a state where the side wall 5 is lowered and the second region R2 in the lower end portion 5a of the side wall 5 is in contact with the bottom plate 4. However, the lower end portion removing step may be performed before the second region R2 in the lower end portion 5a of the side wall 5 is landed on the bottom plate 4. In addition, since the part of 1st area | region R1 of the side wall 5 is guided to the deformation | transformation guide part 8, and is extended to radial direction outer side with the fall of the side wall 5, it may hardly inhibit the fall of the side wall 5. Accordingly, the portion of the first region R1 may be removed at an appropriate timing. Or the part of 1st area | region R1 may not be cut | disconnected until after completion | finish of tank disassembly, but the whole may be removed after tank disassembly.

  As described above, by continuing the lowering of the side wall 5, the side wall 5 is gradually removed from the lower end. Thus, the tank dismantling method is completed by repeatedly performing the lowering step, the lower end forming step for continuing the lowering of the side wall 5, and the notch forming step, and removing the upper end portion 5 b of the side wall 5.

  Here, the structure of the deformation | transformation guide part 8 is demonstrated. Although detailed illustration is omitted in FIGS. 2 to 7, the configuration of the deformation guide portion 8 is as shown in FIG. 8. FIG. 8 is an enlarged cross-sectional view of a region VIII shown in FIG. 9 is a cross-sectional view taken along the line IX-IX shown in FIG. As shown in FIGS. 8 and 9, the deformation guide portion 8 is disposed between the first region R <b> 1 and the bottom plate 4. The deformation guide portion 8 includes two guide bases 81 arranged along the circumferential direction.

  The guide table 81 includes a lower member 82, a first diagonal member 83, and a second diagonal member 84. The lower material 82, the first diagonal material 83, and the second diagonal material 84 are made of, for example, a steel frame material. As the steel frame, for example, H-shaped steel can be adopted.

  The guide base 81, the lower member 82, the first diagonal member 83, and the second diagonal member 84 form a substantially isosceles triangular shape having the lower member 82 as the bottom and the first diagonal member 83 and the second diagonal member 84 as equal sides. Is formed. The lower member 82 and the first diagonal member 83, the lower member 82 and the second diagonal member 84, and the first diagonal member 83 and the second diagonal member 84 are joined to each other, for example, by welding, bolt joining or the like. The lower member 82 and the first diagonal member 83, and the lower member 82 and the second diagonal member 84 are joined to form an angle of 65 °, for example. The guide table 81 guides the first region R1 of the descending side wall 5 to the outer side in the radial direction of the tank 1, so that the joint portion between the lower member 82 and the second diagonal member 84, and the first diagonal member 83 and the second diagonal member 82. Installed between the side wall 5 and the bottom plate 4 so that the joint between the diagonal member 84 is located inside the tank 1 and the joint between the lower member 82 and the first diagonal member 83 is located outside the tank 1. Has been.

  The lower member 82 is installed on the bottom plate 4 and extends on the bottom plate 4 along the radial direction. Each of the first diagonal member 83 and the second diagonal member 84 extends obliquely upward from one end 82a and the other end 82b of the lower member 82 in the radial direction so as to approach each other. The upper surface of the first diagonal member 83 is the guide surface 83 s of the deformation guide portion 8 described above, and the guide surface 83 s forms an angle of 65 ° with respect to the bottom plate 4 and the side wall 5. The guide surface 83 s of the deformation guide portion 8 is formed so as to descend from the inside of the tank 1 toward the outside of the tank 1. When the deformation guide portion 8 is installed between the first region R1 and the bottom plate 4, when the side wall 5 is lowered, the guide surface 83s of the deformation guide portion 8 deviates from the first region R1 outside the outer wall surface 5s. Guide and deform in the direction.

  Further, the deformation guide portion 8 further includes a stopper 85. The fastener 85 is joined to one end 82a on the lower member 82 by, for example, welding, bolt joining, or the like. The fastener 85 is made of, for example, a steel frame. For example, an angle can be adopted as the steel frame material.

  The fasteners 85 are provided so as to bridge between the lower members 82 of the two guide bases 81. The fastener 85 is provided such that the outer surface 85s of the vertical portion 85a at the angle faces the guide surface 83s. Therefore, when the first region R1 descends along the guide surface 83s of the deformation guide portion 8 due to the descending of the side wall 5 in the descending step, the first region R1 when the lower end edge of the first region R1 hits the outer surface 85s of the angle. Is further restricted from descending. Since the lowering of the first region R1 is restricted, the entire side wall 5 can be restricted from falling.

  Next, the effect of the tank disassembly method according to the first embodiment will be described.

  According to the tank disassembly method according to the present embodiment, the deformation guide portion 8 is installed between the first region R1 and the bottom plate 4 (base portion 7). The deformation guide portion 8 has a guide surface 83s that guides and deforms the first region R1 in the out-of-plane direction of the outer wall surface 5s in the side wall 5 when the side wall 5 is lowered. When a cut 52 is formed in the side wall 5 along the boundary line L2 between the first region R1 and the second region R2, and the second region R2 at the lower end portion 5a of the side wall 5 is removed and the side wall 5 is lowered, the first region R1 Is deformed by being guided in the out-of-plane direction, and the second region R2 descends toward the base portion 7. At this time, the side wall 5 descends while receiving a resistance force resulting from the deformation of the first region R1. As a result, for example, the tank 1 can be disassembled with a simple configuration as compared with the case where the side wall 5 is lowered while the load on the side wall 5 is supported by a jack, and the tank 1 can be removed without using a large-scale device. It becomes possible to dismantle.

  In the tank dismantling method according to the present embodiment, the lower end portion removing step is executed in a state where the second region R2 of the descending side wall 5 is in contact with the base portion 7. Accordingly, the second region R2 of the side wall 5 can be removed in a state where the second region R2 of the side wall 5 is in contact with the base portion 7 and the side wall 5 is supported by the base portion 7. Therefore, during the cutting of the second region R2, it is possible to omit measures such as supporting the cut portion with another jig in order to prevent the cut portion from falling.

  The tank disassembly method according to the present embodiment further includes a notch forming step of forming a notch 51 for removing the first region R1 at the lower end portion 5a of the side wall 5 and installing the deformation guide portion 8. In this case, a place for installing the deformation guide portion 8 can be secured by the notch 51. In this case, in the lower end portion removing step, the cutting line L1 for removing the second region R2 other than the notch 51 in the lower end portion 5a of the side wall 5 may be a horizontal straight line. Can be performed easily. Therefore, the dismantling operation of the tank 1 can be performed with a simpler configuration.

  In the tank disassembling method according to the present embodiment, in a state where the deformation guide portion 8 is installed, a notch forming process for extending the notch 52 and a descending process are repeatedly executed. In the descending step, the side wall 5 descends according to the amount of the notches 52 formed in the notch forming step. Therefore, the side wall 5 can be lowered stepwise with respect to the range where the lower end portion 5a is removed by forming the cut 52 to be extended. Therefore, the side wall 5 can be slowly lowered as compared with the case where the cut 52 is formed at a time in the range where the lower end portion 5a is removed.

  As mentioned above, although embodiment of this invention was described in detail, this invention can be implemented in the various aspects which gave various change and improvement based on the knowledge of those skilled in the art including the above-mentioned embodiment. it can. In addition, various modifications can be configured using the technical matters described in the above-described embodiments.

  For example, the circumferential lengths of the first region and the second region may be arbitrarily set. For example, in order to slow down the speed at which the side walls descend, the first region may be made wider than the first region R1 to increase the resistance force resulting from the deformation of the first region.

  In the above-described embodiment, the tank 1 including the roof 6 has been described as an example. However, the tank may not include the roof. The tank to which the dismantling method of the present invention is applied may be, for example, a floating roof type crude oil tank, a gas gas storage tank of a water-containing holder, or the like. Moreover, a tank provided with the inner tank as a side wall and the outer tank which covers the upper part of the storage space S while being located in the outer side of an inner tank may be sufficient as a tank.

  Moreover, in the above-mentioned embodiment, although the joining location with the bottom plate 4 in the lower end part 5a of the side wall 5 was cut | disconnected and mentioned as an example, the side wall 5 was cut | disconnected from the bottom plate 4, and this was demonstrated as an example, It is not limited to such a configuration. It is sufficient that the side wall is separated from the bottom plate in the lowering process. For example, the side wall and the bottom plate joined together by bolt joint are released from the bolt joint and the bottom plate 4 is removed, and the side wall is removed in the lowering process. It is good also as a state separated from the bottom plate.

  In the above-described embodiment, the deformation guide portion 8 including the stopper metal 85 has been described as an example. However, the deformation guide portion 8 may not include the stopper metal 85. Further, the guide base 81 of the deformation guide portion 8 may not include the lower material 82 made of H-shaped steel, the first diagonal material 83, and the second diagonal material 84. The deformation guide portion 8 only needs to have a guide surface that guides and deforms the lower end portion of the descending side wall in the out-of-plane direction of the wall surface of the side wall. For example, the deformation guide portion 8 may be made of wood.

  In the lowering process, the configuration in which the side wall 5 is lowered by its own weight has been described as an example. However, in the lowering process, a force different from the weight of the side wall may be applied to lower the side wall. Good. In the lowering step, for example, a jack may be used to lower the side wall by pulling it from below, or the side wall may be pressed from above to lower the side wall.

  DESCRIPTION OF SYMBOLS 1 ... Tank, 4 ... Bottom plate, 5 ... Side wall, 5a ... Lower end part, 5s ... Outer wall surface (wall surface), 7 ... Base part, 8 ... Deformation guide part, 51 ... Notch, 51s ... Upper edge part (edge part) 52 ... cut, 83s ... guide plane, L2 ... boundary line, R1 ... first region, R2 ... second region.

Claims (4)

A tank dismantling method for disassembling a tank comprising a bottom plate and a side wall extending upward from the bottom plate,
In the lower end portion of the side wall, the first region and the second region are alternately arranged in the circumferential direction,
A deformation guide having a guide surface between the base portion including the bottom plate and the first region, the guide surface deforming by guiding the first region in an out-of-plane direction of the wall surface of the side wall when the side wall is lowered. Department is installed,
A notch forming step of forming a notch in the side wall along a boundary line between the first region and the second region;
A lower end removing step of removing the second region at the lower end;
A step of lowering the side wall in a state where the base portion and the side wall are separated, and
The tank dismantling method, wherein, in the descending step, the first region of the descending side wall is guided and deformed by a guide surface of the deformation guide portion. The lower end removing step includes
The tank disassembly method according to claim 1, wherein the tank disassembly method is executed in a state where the second region of the descending side wall is in contact with the foundation.   3. The tank disassembly method according to claim 1, further comprising a notch forming step of forming a notch for removing the first region at the lower end portion and installing the deformation guide portion.   The tank dismantling method according to claim 3, wherein in the state where the deformation guide portion is installed, the notch forming step of extending the notch and the lowering step are repeatedly executed.

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