JP6347413B2 - Tank roof opening method - Google Patents

Description

  The present invention relates to a tank roof opening method for opening a tank roof structure for storing liquefied gas therein.

  A liquefied gas such as liquefied natural gas (LNG) or liquefied petroleum gas (LPG) is stored in a tank in a low temperature liquid state. This tank has a double shell structure in order to keep the internal storage space for storing the liquefied gas at a low temperature. That is, the double shell structure prevents heat from entering the storage space inside the tank from the outside of the tank.

  Such a tank (hereinafter simply referred to as a tank) is described in, for example, Patent Document 1 below. The tank which stores liquefied gas is provided with the inner structure which has the inner surface which forms a storage space as a double shell structure, and the outer structure body which covers an inner structure from the outside like patent document 1. FIG. A heat insulating space is formed between the inner structure and the outer structure. The heat insulating space is filled with a granular heat insulating material (for example, pearlite) in order to prevent heat from being transferred from the outside of the tank to the storage space.

Japanese Patent No. 3528241

  The inner structure of the tank has an inner roof. The outer structure of the tank has an outer roof of the tank. The above-described heat insulating space is formed between the inner roof and the outer roof.

  In existing tanks, penetrate the tank roof structure (ie inner and outer roofs) to inspect the condition in the storage space (liquefied gas level, temperature, pressure, or liquefied gas density) There is a case where an inspection device (inspection nozzle) for inspecting the state in the storage space is inserted into the storage space from the outside of the tank through the through hole.

  However, a heat insulating space filled with granular heat insulating material exists between the inner roof and the outer roof.

  In addition, bone members extending radially from the center side of the tank roof are provided on the lower surface of the outer roof. For this reason, it is difficult to form a work area having a size larger than the interval between the bone members (an area where a person performs a work for placing the inspection device) between the inner roof and the outer roof.

  Therefore, an object of the present invention is to provide a large number of bone members provided on the lower surface of the outer roof in a tank roof structure including an inner roof and an outer roof, and a granular heat insulating material filled in a heat insulating space between the two. It is an object of the present invention to provide a method capable of forming a work area having a size larger than the distance between the inner roof and the outer roof.

In order to achieve the above-described object, according to the present invention, there is provided a tank roof opening method for opening a roof structure of a tank for storing liquefied gas therein.
The tank has a storage space for storing liquefied gas,
The roof structure includes an inner roof that covers an upper portion of the storage space;
An outer roof covering the inner roof from above;
A granular heat insulating material filled in a heat insulating space between the inner roof and the outer roof,
A large number of bone members extending radially from the center side of the outer roof are attached to the lower surface of the outer roof,
(A) Forming a plurality of slits that extend so as to surround the target region on the upper surface of the outer roof and that are divided at the outer roof so as to avoid overlapping with the bone members in the thickness direction of the outer roof, , Through the outer roof in the thickness direction,
(B) By inserting a plurality of shielding plates into the plurality of slits, respectively, in the heat insulating space, a work area surrounded by the plurality of shielding plates is formed,
(C) Take out the granular heat insulating material from the work area through the existing heat insulating material filling hole located in the target area, or the heat insulating material extraction through hole formed in the target area,
(D) In the target area of the outer roof, an outer opening that penetrates the outer roof in its thickness direction is formed,
(E) In the work area, a tank roof opening method is provided, wherein an inner opening communicating with the storage space of the tank is formed in the inner roof.

  The tank roof opening method of the present invention can be performed, for example, as follows.

Each blocking plate inserted into the slit in (B) has an outer portion extending upward from the slit,
After (B) and before (C), a rib is fixed to the outer portion of the shielding plate, and the rib is fixed to the upper surface of the outer roof.

  Thus, since a rib is fixed to the outer part of the shielding plate and this rib is fixed to the upper surface of the outer roof, the shielding plate can be reinforced. That is, each shielding plate is stably supported by the outer roof.

In the (B), one of the blocking plates disposed on both sides of the bone member so as to sandwich the bone member is in a state where the lower end is in contact with the upper surface of the inner roof, and the bone member A region having the same height as the above has a notch that is recessed in the width direction of the bone member,
In (B), the plurality of blocking plates are respectively inserted into the plurality of slits, and after the lower ends of these blocking plates are brought into contact with the upper surface of the inner roof, the blocking plate having the cutout portion. Is moved in the width direction of the bone member, and the bone member is positioned in the notch, thereby closing the gap region overlapping the bone member in the thickness direction of the outer roof in the heat insulating space with the blocking plate. .

  As described above, the blocking plate having the notch is moved in the width direction of the bone member so that the bone member is positioned in the notch. Therefore, in the heat insulating space, the bone member is arranged in the thickness direction of the outer roof. The overlapping area can be closed with a blocking plate. As a result, in the heat insulation space, a work area with a higher degree of sealing can be formed with respect to the area of the other heat insulation space.

  In (B), by moving the blocking plate having the cutout portion in the width direction of the bone member, the longitudinal direction range of the slit where the blocking plate is not positioned by the amount of the movement is different. Insulation plate is inserted.

  In this way, by moving the blocking plate having the notch in the width direction of the bone member, another blocking plate is provided in the longitudinal direction range of the slit where the blocking plate is not positioned by the amount of the movement. Inserted. Therefore, even if the blocking plate having the notch is moved in the width direction of the bone member, the blocking plate can exist in the entire longitudinal direction of the slit.

Before (C)
In the outer roof, at a position adjacent to the slit, a through hole for inserting a column member is formed,
The column member is inserted into the through hole, and the column member is fixed to the outer roof with the lower end of the column member in contact with the upper surface of the inner roof, and the blocking plate inserted into the slit is fixed to the column member. To do.

  Thus, since the column member is provided, the column member is fixed to the outer roof, and the blocking plate is fixed to the column member, the blocking plate is reinforced by the column member.

The upper surface of the outer roof where the target area is set is inclined with respect to the horizontal plane,
The target area has a rectangular outer edge,
The rectangle is
A first side extending in a horizontal direction;
A second extending in the horizontal direction so as to connect the second and third sides extending downward along the upper surface of the outer roof from both ends of the first side and the lower ends of the second and third sides. A side, and
In (A), the slit is formed in each of the first, second, third, and fourth sides.

  Thus, since the slit is formed on each side of the quadrilateral and the blocking plate is inserted into each slit, it is possible to form a work area surrounded from four sides. In particular, the blocking plate inserted into the slit on the fourth side can prevent a person working in the work area from falling downward.

  According to the present invention described above, a plurality of slits that extend so as to surround a target region on the upper surface of the outer roof and that are divided at the portion so as to avoid a portion overlapping with the bone member in the thickness direction of the outer roof are formed. A plurality of blocking plates are inserted into these slits. Thereby, the work area surrounded by a plurality of blocking plates can be formed between the outer roof and the inner roof.

  As described above, the plurality of slits arranged so as to avoid the plurality of bone members can form a work area having a size larger than the interval between the many bone members.

  Thereafter, the particulate heat insulating material can be taken out of the work area to form an outer opening in the target area of the outer roof, and in the work area, an inner opening communicating with the storage space of the tank can be formed in the inner roof.

(A) is the side which shows the tank which can be made into the object of the tank roof opening method of this invention, (B) is a BB arrow directional view of FIG. 1 (A), and shows the lower surface of an outer roof. . 3 is a flowchart of a tank roof opening method according to an embodiment of the present invention. (A) is the III-III arrow directional view of FIG. 1 (A), Comprising: It is a figure for demonstrating the procedure of the tank roof opening method, (B) demonstrates the procedure of the tank roof opening method. It is another figure for doing. (A) is sectional drawing in the IVA-IVA line | wire of FIG. 3 (B), (B) is a figure corresponding to (A). It is another figure for demonstrating the procedure of the tank roof opening method. (A) is sectional drawing in the VIA-VIA line | wire of FIG. 5 (B), (B) is sectional drawing in the VIB-VIB line | wire of FIG. 7 (B). It is another figure for demonstrating the procedure of the tank roof opening method. It is another figure for demonstrating the procedure of the tank roof opening method corresponding to FIG. 6 (B).

  A preferred embodiment of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the overlapping description is abbreviate | omitted.

  Based on FIG. 1, the tank used as the object of the tank roof opening method of this invention is demonstrated.

  FIG. 1 (A) is a side view showing a tank 10 which is an object of the tank roof opening method of the present invention. FIG. 1B is a BB line arrow view of FIG. 1A and shows a lower surface of an outer roof 7b described later. In FIG. 1B, illustration of the inner roof 5b is omitted.

  The tank 10 has a storage space 3 for storing liquefied gas therein. The liquefied gas is liquefied natural gas or liquefied petroleum gas. The tank 10 includes, as a double shell structure, an inner structure 5 having an inner surface forming the storage space 3 and an outer structure 7 that covers the inner structure 5 from the outside. A heat insulating space 9 is formed between the inner structure 5 and the outer structure 7.

  The inner structure 5 has an inner wall 5a and an inner roof 5b. The inner wall 5 a forms the inner peripheral surface of the storage space 3. The inner roof 5b is coupled to the upper end portion of the inner wall 5a. The inner roof 5b closes the upper part of the storage space 3 for storing the liquefied gas.

  The outer structure 7 has an outer wall 7a and an outer roof 7b. The outer side wall 7a extends in the circumferential direction so as to surround the inner side wall 5a. The outer roof 7b is coupled to the upper end portion of the outer wall 7a. The outer roof 7b covers the inner roof 5b from above.

  As shown in FIG. 1 (B), a large number of bone members 13 extending radially from the center side of the outer roof 7b are attached to the lower surface 11 of the outer roof 7b. Each bone member 13 protrudes downward from the lower surface 11 of the outer roof 7b in the thickness direction of the outer roof 7b. Further, as shown in FIG. 1B, a reinforcing member 12 extending in the circumferential direction of the outer roof 7b is also attached to the lower surface 11 of the outer roof 7b.

  A heat insulating space 9 is formed between the inner structure 5 and the outer structure 7. The heat insulating space 9 is filled with a granular heat insulating material. The granular heat insulating material is granular pearlite in the present embodiment. Perlite is obtained by crushing obsidian, nacre, pine sebite, etc., and rapidly heating and expanding.

  The roof structure of the tank 10 is constituted by the inner roof 5b, the outer roof 7b, and the granular heat insulating material filled in the heat insulating space 9 between the inner roof 5b and the outer roof 7b.

  The center part of the upper surface 15 of the outer roof 7b is higher than the outer periphery of the upper surface 15 of the outer roof 7b as shown in FIG. The upper surface 15 of the outer roof 7b is gradually lowered from the central portion of the outer roof 7b to the outer peripheral edge of the outer roof 7b. Similarly, the center part of the upper surface 17 of the inner roof 5b is higher than the outer peripheral edge of the upper surface 17 of the inner roof 5b. The upper surface 17 of the inner roof 5b is gradually lowered from the center of the inner roof 5b to the outer peripheral edge of the inner roof 5b.

  FIG. 2 is a flowchart of the tank roof opening method.

  Next, a tank roof opening method for opening the roof of the tank 10 described above will be described with reference to FIG. 2 and other drawings.

  FIG. 3A is a view taken along the line III-III in FIG. 1A and shows a part of the upper surface 15 of the outer roof 7b.

  In step S1, as shown in FIG. 3 (A), the outer roof 7b extends so as to surround the target region R0 (the region surrounded by the one-dot chain line in FIG. 3 (A)) on the upper surface 15 of the outer roof 7b. A plurality of slits 19 divided at these portions are formed so as to avoid a portion overlapping with the bone member 13 in the thickness direction. Each slit 19 penetrates the outer roof 7b in the upper thickness direction of the outer roof 7b.

  In addition, the upper surface 15 of the outer roof 7b on which the target region R0 is set is inclined with respect to the horizontal plane.

  In the target region R0, an existing heat insulating material filling hole (hole) 31 is positioned on the outer roof 7b. The heat insulating material filling hole 31 can be opened and closed. The heat insulating material filling hole 31 in an open state allows the outside of the tank 10 to communicate with the heat insulating space 9 between the inner roof 5b and the outer roof 7b. It is possible to supply the heat insulating material to the heat insulating space 9 through the heat insulating material filling hole 31 in the opened state or to extract the heat insulating material from the heat insulating space 9.

  In the present embodiment, the target region R0 is set so as not to overlap with the reinforcing member 12 (see FIG. 1B) in the thickness direction of the outer roof 7b.

  In the present embodiment, the target region R0 has a rectangular (in a preferred example, a trapezoid) outer edge. As shown in FIG. 3A, the quadrangle includes a first side L1 extending in the horizontal direction, a second side extending from the both ends of the first side in a direction along the upper surface 15 of the outer roof 7b, and the second side. It has 3rd edge | side L2, L3 and 4th edge | side L4 extended in a horizontal direction so that the lower end of 2nd and 3rd edge | side L2, L3 may be connected.

  In step S1, slits 19 are formed in each of the first to fourth sides L1, L2, L3, and L4.

  In the present embodiment, in step S1, a pillar member 25 described later is provided at a position that avoids a portion overlapping the bone member 13 in the thickness direction of the outer roof 7b and is adjacent to the slit 19 in step S1. A through-hole 21 for inserting a hole is formed. In the example of FIG. 3A, the column member 25 described later has a U-shaped cross section, and thus forms a U-shaped through hole 21.

  Next, step S2 will be described.

  FIG. 3B is a diagram corresponding to FIG. 3A (that is, a diagram viewed from the same direction; the same applies hereinafter), and is an explanatory diagram of step S2. 4A is a cross-sectional view taken along the line IVA-IVA in FIG. 3B and is an explanatory diagram of step S2. FIG. 4B is also an explanatory diagram of step S2 corresponding to FIG. FIG. 5A is also an explanatory diagram of step S2 corresponding to FIG.

  In step S2, as shown in FIG. 3B, a plurality of blocking plates 23 are inserted into the plurality of slits 19, respectively. Thereby, in the heat insulation space 9, the work area enclosed with the some shielding board 23 is formed. At this time, each shielding plate 23 extends downward in the thickness direction of the outer roof 7b from an outer portion 23b (see FIG. 4A described later) located above the upper surface 15 of the outer roof 7b. The lower end is in contact with the upper surface 17 of the inner roof 5b. Each blocking plate 23 has a rectangular side surface.

  Preferably, as shown in FIG. 4 (A), one of the blocking plates 23 arranged on both sides of the bone member 13 so as to sandwich the bone member 13 is lower on the upper surface 17 of the inner roof 5b. A region having the same height as the bone member 13 has a notch 23 a that is recessed in the width direction Dw of the bone member 13. The width direction Dw of one bone member 13 is shown in FIG. In the example of FIG. 4A, the blocking plate 23 has a shape in which a corner portion of the rectangular side surface is notched to form a notch portion 23a.

  In this case, first, as described above, in step S2, the plurality of blocking plates 23 are respectively inserted into the plurality of slits 19, and the lower ends of these blocking plates 23 are set inside as shown in FIG. After making contact with the upper surface 17 of the roof 5b, each of the shielding plates 23 having the notches 23a (hereinafter simply referred to as notched shielding plates 23) is formed on the bone member 13 adjacent to the notched shielding plate 23. Shift (move) in the width direction Dw. As a result, as shown in FIG. 4B, the bone member 13 and the portion of the outer roof 7b overlapping the bone member 13 in the thickness direction of the outer roof 7b are positioned in the notch 23a. Thereby, in the heat insulation space 9, the clearance area R1 (area surrounded by a broken line in FIG. 4A) overlapping the bone member 13 in the thickness direction of the outer roof 7b is closed by the blocking plate 23. This state is shown in FIGS. 4B and 5A.

  FIG. 4B shows the case of each blocking plate 23 inserted into the slit 19 on the fourth side L4 of the target region R0 described above, but the slit 19 on the first side L1 of the target region R0. Each of the blocking plates 23 inserted in is also the same as described above.

  On the other hand, the second and third sides L2, L3 of the target region R0 described above do not overlap with the bone member 13 in the thickness direction of the outer roof 7b. Therefore, each blocking plate 23 inserted into the slit 19 on the second and third sides L2 and L3 does not have the above-described notch 23a.

  In this way, in step S2, the notched blocking plate 23 is moved in the width direction Dw of the bone member 13, so that the amount of this movement is within the longitudinal range of the slit 19 where the blocking plate 23 is not located. Another blocking plate 23 is inserted. This may be done, for example, as follows. As shown in FIGS. 3 (B) and 4 (A), in step S2, the notched blocking plate 23 and another blocking plate 23 are connected to the same slit 19 (in FIG. The slits 19) on the fourth sides L1 and L4 are inserted so as to partially overlap in the width direction of the slits 19). Thereafter, for example, as shown in FIGS. 4B and 5A, by moving the notched blocking plate 23 in the width direction Dw of the bone member 13, the blocking plate 23 is positioned by the amount of this movement. In the longitudinal direction range of the slit 19 that does not occur, the above-described another blocking plate 23 is already positioned. Accordingly, the blocking plate 23 can be present in the entire longitudinal direction of the slit 19.

  In the present embodiment, in step S2, as shown in FIG. 5A, the column member 25 is inserted into the through hole 21 formed in step S1.

  Next, step S3 will be described.

  In step S3, each shielding plate 23 is fixed to the outer roof 7b by welding. That is, each blocking plate 23 has an outer portion 23b (see FIG. 4) positioned above the upper surface 15 of the outer roof 7b, and the outer portion 23b is fixed to the outer roof 7b by welding. At this time, the lower end of each blocking plate 23 is in contact with the upper surface 17 of the inner roof 5b.

  In step S3, the column member 25 (the outer portion 25a above the upper surface 15 of the outer roof 7b (see FIG. 6A described later)) is fixed to the outer roof 7b by welding and inserted into the slit 19 The shield plate 23 is fixed to the column member 25 by welding. At this time, the lower end of each column member 25 is in contact with the upper surface 17 of the inner roof 5b.

  Next, step S4 will be described.

  FIG. 5B is an explanatory diagram of step S3 corresponding to FIG. FIG. 6A is a cross-sectional view taken along line VIA-VIA in FIG.

  In step S4, as shown in FIGS. 5B and 6A, the ribs 27 are fixed to the outer portions 23b of the respective shielding plates 23 by welding. Moreover, in step S4, each rib 27 is fixed to the upper surface 15 of the outer roof 7b by welding.

  In the present embodiment, each rib 27 is a plate-like member. In the present embodiment, the plate-like ribs 27 are fixed to the side surfaces so as to be orthogonal to the side surfaces of the blocking plate 23. Accordingly, each rib 27 extends in a direction perpendicular to the slit 19 in which the blocking plate 23 to which the rib 27 is fixed is inserted. In this example, one or more on both side surfaces of each blocking plate 23 inserted in the slit 19 on the first side L1 and the fourth side L4 (see FIG. 3A) of the target region R0. The rib 27 is fixed by welding. However, one or more ribs are also provided on both side surfaces of each blocking plate 23 inserted in the slit 19 on the second side L2 and the third side L3 (see FIG. 3A) of the target region R0. 27 may be fixed.

  Preferably, in step S4, the ribs 27 are also fixed to the column members 25 by welding. Each column member 25 has an outer portion 25a (FIG. 6A) positioned above the upper surface 15 of the outer roof 7b in a state where the lower end thereof is in contact with the upper surface 17 of the inner roof 5b. See). In step S4, the rib 27 is preferably fixed to the outer portion 25a of each column member 25 by welding, and the rib 27 is fixed to the upper surface 15 of the outer roof 7b by welding. The shape of the rib 27 fixed to the column member 25 may be the same shape as the rib 27 fixed to the outer portion 23 b of the blocking plate 23.

  Next, step S5 will be described.

  FIG. 7A is an explanatory diagram of step S5 corresponding to FIG.

  In step S5, as shown in FIG. 7A corresponding to FIG. 5B, a draining plate 29 rising upward from the upper surface 15 is installed on the upper surface 15 of the outer roof 7b. The draining plate 29 is fixed to the upper surface 15 of the outer roof 7b by welding, for example. As shown in FIG. 7A, the draining plate 29 is located at a position closer to the center side (upper side) of the roof of the tank 10 than the first side L1 of the target region R0 (see FIG. 3A). Be placed. The draining plate 29 prevents rainwater from flowing from the center side of the roof of the tank 10 through the upper surface 15 of the outer roof 7 b and entering the slit 19 and the blocking plate 23. That is, when it takes several days or more to complete the tank roof opening method according to the present embodiment, rainwater entering the target region R0 can be suppressed by the draining plate 29 even if it rains. In this case, when it rains, in addition to the draining plate 29, it is preferable to arrange a vinyl sheet so as to cover the entire target region R0.

  Next, step S6 will be described.

  In step S6, the granular heat insulating material is taken out from the work area partitioned by the shielding plate 23 in the heat insulating space 9 through the heat insulating material filling hole 31 located in the target region R0.

  The operation of taking out the granular heat insulating material from the work area may be performed by an appropriate suction device. The sucked granular heat insulating material is temporarily stored in an appropriate container for later return to the work area. In some cases, the sucked granular heat insulating material may be replaced with new granular heat insulating material.

  As described above, steps S1 to S4 are performed before step S6. However, step S5 may be performed after step S6.

  Next, step S7 will be described.

  FIG. 7B is an explanatory diagram of step S7 corresponding to FIG. 6B is a cross-sectional view taken along line VIB-VIB in FIG.

  In step S7, a person forms an outer opening 7c as shown in FIG. 7B using an appropriate tool in the target region R0 of the outer roof 7b. The outer opening 7c penetrates the outer roof 7b in the thickness direction. At this point, since the granular heat insulating material has already been taken out from the work area in step S6, the granular heat insulating material does not come out from the work area through the outer opening 7c in step S7.

  Next, step S8 will be described.

  In step S8, a person enters the work area 9a (see FIG. 6B) through the outer opening 7c and performs various works in the work area 9a. This work includes, for example, the following works (1) to (5).

(1) An appropriate sealing material (for example, glass wool or caulking) is formed in the gap between the blocking plates 23 (for example, the blocking plate 23 with notches and the other blocking plate 23) partially overlapping in the width direction of the slit 19. Close with material.
(2) At the boundary between each pair of adjacent blocking plates 23, the gap between the two is closed with a sealing material (for example, caulking material).
(3) The lower end of each blocking plate 23 and the lower end of each column member 25 are fixed to the upper surface 17 of the inner roof 5b by welding (for example, partially).
(4) The gap between the lower end of each blocking plate 23 and the lower end of each column member 25 and the upper surface 17 of the inner roof 5b is closed with a sealing material (for example, caulking material).
(5) When there is a gap between the work area 9a and the other heat insulating space 9, the gap is closed with a sealing material (for example, caulking material).

  By such work, it can prevent more reliably that a granular heat insulating material approachs into the work area | region 9a from the other area | region of the heat insulation space 9. FIG. As a result, a person can perform the subsequent steps S9 and S10 with peace of mind in the work area 9a.

  Next, step S9 will be described.

  FIG. 8A is an explanatory diagram of step S9 corresponding to FIG.

  In step S9, as shown in FIG. 8A, an inner opening 5c communicating with the storage space 3 of the tank 10 is formed in the inner roof 5b in the work area 9a. In this embodiment, in step S9, a person enters the work area 9a through the outer opening 7c, and uses an appropriate tool to connect the inner roof 5b to the storage space 3 of the tank 10 in the work area 9a. 5c is formed.

  Next, step S10 will be described.

  FIG. 8B is an explanatory diagram of step S10 corresponding to FIG.

  In step S10, the person arranges the inspection device 33 in the storage space 3 through the inner opening 5c in the work area 9a as shown in FIG. 8B. This inspection device 33 is fixed to the inner roof 5b, for example. In the example of FIG. 6, the inspection device 33 includes a fixed portion 33 a fixed to the inner roof 5 b, an extension portion 33 b extending from the fixed portion 33 a into the storage space 3, and a sensor portion 33 c located at the tip of the extension portion 33 b. And having. The sensor unit 33c detects, for example, the pressure or temperature in the storage space 3, the liquid level of the liquefied gas in the storage space 3, or the density of the liquefied gas.

  Thereafter, the person leaves the work area 9a through the outer opening 7c. Next, in a state where the inspection device 33 is installed as described above, the granular heat insulating material temporarily stored in the work area 9 a is returned to the work area 9 a through the hole 31 for filling the heat insulating material. Alternatively, the exchanged new granular heat insulating material is filled into the work area 9 a through the heat insulating material filling hole 31. Thereafter, the outer opening 7c is closed with an appropriate plate-like member. Next, each shielding plate 23 and column member 25 are removed from the outer roof 7b. Thereafter, the slit 19 is closed with appropriate means.

  The present invention is not limited to the above-described embodiment, and various changes can be made without departing from the scope of the present invention.

  For example, in the above description, the heat insulating material filling hole 31 is located in the target region R0, but if not, the following may be performed. In the target region R0, a heat-insulating material extraction through-hole that penetrates the outer roof 7b in the thickness direction is formed. A granular heat insulating material is taken out from the work area 9a through the through hole for heat insulating material extraction. In this case, after the inspection device 33 is installed, the granular heat insulating material temporarily stored is returned to the work area 9a through the through hole for taking out the heat insulating material (or the replaced new granular heat insulating material is worked). Fill the region 9a). In this case, the other points are the same as described above.

3 storage space, 5 inner structure, 5a inner wall, 5b inner roof, 5c inner opening, 7 outer structure, 7a outer wall, 7b outer roof, 7c outer opening, 9 heat insulation space, 9a work area, 10 tank, 11 Lower surface of outer roof, 12 Reinforcement member, 13 Bone member, 15 Upper surface of outer roof, 17 Upper surface, 19 Slit, 21 Through hole, 23 Blocking plate, 23a Notch, 23b Outer portion of blocking plate, 25 Column member, 25a Outside part of column member, 27 rib, 29 draining board, 31 hole for heat insulation filling, 33 inspection equipment, R0 target area

Claims (6)

A tank roof opening method for opening a tank roof for storing liquefied gas therein,
The tank has a storage space for storing liquefied gas,
The roof includes an inner roof that covers an upper portion of the storage space;
An outer roof covering the inner roof from above;
A granular heat insulating material filled in a heat insulating space between the inner roof and the outer roof,
A large number of bone members extending radially from the center side of the outer roof are attached to the lower surface of the outer roof,
(A) Forming a plurality of slits that extend so as to surround the target region on the upper surface of the outer roof and that are divided at the outer roof so as to avoid overlapping with the bone members in the thickness direction of the outer roof, , Through the outer roof in the thickness direction,
(B) By inserting a plurality of shielding plates into the plurality of slits, respectively, in the heat insulating space, a work area surrounded by the plurality of shielding plates is formed,
(C) Take out the granular heat insulating material from the work area through the existing heat insulating material filling hole located in the target area, or the heat insulating material extraction through hole formed in the target area,
(D) In the target area of the outer roof, an outer opening that penetrates the outer roof in its thickness direction is formed,
(E) In the work area, an inner opening that communicates with the storage space of the tank is formed in the inner roof. Each blocking plate inserted into the slit in (B) has an outer portion extending upward from the slit,
The rib according to claim 1, wherein after (B) and before (C), a rib is fixed to the outer portion of the shielding plate, and the rib is fixed to the upper surface of the outer roof. Tank roof opening method. In the (B), one of the blocking plates disposed on both sides of the bone member so as to sandwich the bone member is in a state where the lower end is in contact with the upper surface of the inner roof, and the bone member A region having the same height as the above has a notch that is recessed in the width direction of the bone member,
In (B), the plurality of blocking plates are respectively inserted into the plurality of slits, and after the lower ends of these blocking plates are brought into contact with the upper surface of the inner roof, the blocking plate having the cutout portion. Is moved in the width direction of the bone member, and the bone member is positioned in the notch, thereby closing the gap region overlapping the bone member in the thickness direction of the outer roof in the heat insulating space with the blocking plate. The tank roof opening method according to claim 1 or 2, characterized by the above-mentioned.   In (B), by moving the blocking plate having the cutout portion in the width direction of the bone member, the longitudinal direction range of the slit where the blocking plate is not positioned by the amount of the movement is different. The tank roof opening method according to claim 3, wherein a barrier plate is inserted. Before (C)
In the outer roof, at a position adjacent to the slit, a through hole for inserting a column member is formed,
The column member is inserted into the through hole, and the column member is fixed to the outer roof with the lower end of the column member in contact with the upper surface of the inner roof, and the blocking plate inserted into the slit is fixed to the column member. The tank roof opening method according to any one of claims 1 to 4, wherein the tank roof opening method is performed. The upper surface of the outer roof where the target area is set is inclined with respect to the horizontal plane,
The target area has a rectangular outer edge,
The rectangle is
A first side extending in a horizontal direction;
A second extending in the horizontal direction so as to connect the second and third sides extending downward along the upper surface of the outer roof from both ends of the first side and the lower ends of the second and third sides. A side, and
In said (A), the said slit is formed in each of the 1st, 2nd, 3rd, and 4th edge | side, The tank roof as described in any one of Claims 1-5 characterized by the above-mentioned. Opening method.

Images