KR20160029882A - Cargo barrier structure - Google Patents

Abstract

A cargo hold barrier structure is disclosed. The cargo hold barrier structure, according to an embodiment of the present invention, comprises: an upper insulation board which is arranged in the bottom of a primary barrier and has an upper protection plate and an upper insulation member formed on the bottom surface of the upper protection plate; a secondary barrier which is arranged in the bottom of the upper insulation member; and a lower insulation board which is arranged in the bottom of the secondary barrier and has a lower insulation member and a lower protection plate formed on the bottom surface of the lower insulation member, wherein the upper insulation member has lower density than the lower insulation member. Therefore, the present invention provides the barrier structure considering the structural strength of the insulation board.

Description

Cargo barrier structure {CARGO BARRIER STRUCTURE}

The present invention relates to a cargo hold barrier structure.

Since the cargo hold of a ship stores liquefied natural gas (LNG) cooled to approximately -163 ℃, it can withstand the cryogenic temperature to protect the hull. It is resistant to thermal stress and heat shrinkage, . For example, floating structures including LNG carrier, LNG RV (Regasification Vessel), LNG FPSO (Floating Production Storage and Offloading) and LNG FSRU (Floating Storage Regulation Unit) . The structure of the cargo holds is composed of a primary barrier, an upper insulation board, a secondary barrier and a lower insulation board. This is to prevent further leakage of the fluid in the secondary barrier if there is a small leakage of the cryogenic fluid in the primary barrier.

The above-mentioned upper and lower heat insulating boards are usually formed by adding glass fiber (CSM, Continuous Strand Mat) appropriately to polyurethane foam (PUF) to improve tensile properties, thereby forming a high density reinforced poly And a heat insulating member made of urethane foam (R-PUF, Reinforced PUF). When a cryogenic fluid such as LNG is loaded in the cargo hold, a temperature gradient occurs in the upper and lower insulation boards. In other words, the temperature changes from -163 ° C to -62 ° C to + 45 ° C from the inside of the hold filled with LNG to the vicinity of the secondary barrier and the hull. At this time, the mechanical properties of the reinforced polyurethane foam used for the heat insulating members of the upper and lower heat insulating boards are increased as the temperature is lowered. Therefore, the structural strength of the upper insulation board will increase more than the structural strength of the lower insulation board, especially the compressive strength, when the LNG is stacked.

However, since reinforced polyurethane foam of the same density and material is used for the heat insulating members of the upper and lower heat insulating boards, there has been an excessive design without considering the structural strength according to the exposure temperature of each heat insulating board. As a related art, refer to Korean Patent Laid-Open No. 10-2012-0039861 (published on April 26, 2012).

Korean Patent Laid-Open No. 10-2012-0039861 (2012.04.26. Disclosed)

An embodiment of the present invention is to provide a cargo barrier structure considering the structural strength of a heat insulating board.

According to an aspect of the present invention, there is provided an upper insulation board disposed at a lower portion of a primary barrier, the upper insulation board including an upper protection plate and an upper insulation member at a lower surface thereof; A secondary barrier disposed below the upper insulating member; And a lower insulation board disposed below the secondary barrier and including a lower insulation member and a lower protection plate on the lower surface thereof, wherein the upper insulation member may be provided with a low-density cargo hold barrier structure have.

The heat insulating member may be made of a reinforced polyurethane foam, and the lower heat insulating member may be made of a reinforced polyurethane foam or a polyurethane foam.

Wherein the upper insulating board further comprises a first upper sub-panel interposed between the upper insulating member and the secondary barrier, and the lower insulating board comprises a first lower sub-board interposed between the secondary barrier and the lower heat- Wherein the upper protective plate, the first upper sub-panel and the lower protective plate are made of plywood, and when the lower thermal insulating member is made of a reinforced polyurethane foam, the first lower sub- When the lower heat insulating member is made of polyurethane foam, the first lower sub-panel may be made of one or more of glass fiber reinforced plastic, aluminum and stainless steel.

The upper heat insulating member and the lower heat insulating member may be made of polyurethane foam.

The upper protection plate may be made of glass fiber reinforced plastic, and the lower protection plate may be made of one or more of glass fiber reinforced plastic, aluminum, stainless steel, and plywood.

Wherein the upper insulation board further comprises a first upper sub-panel interposed between the upper insulation member and the secondary barrier, and the lower insulation board comprises a first lower sub-panel interposed between the secondary barrier and the lower insulation board, Wherein the first upper sub-panel is made of at least one of glass fiber reinforced plastic, aluminum, stainless steel and plywood, the first sub-sub-panel comprising at least one of polyurethane foam, aluminum and stainless steel Can be produced.

The upper insulation board may further include a second upper sub-panel interposed between the first upper sub-panel and the second barrier, and a third upper sub-panel disposed above the upper protective plate, A second lower sub-panel interposed between the secondary barrier and the first lower sub-panel, and a third lower sub-panel disposed below the lower protective plate, wherein the second upper sub-panel, the second sub- Panel, the third upper sub-panel, and the third lower sub-panel may be made of a plywood material.

The density of the upper heat insulating member may be 90 to 110 kg / m 3, and the density of the lower heat insulating member may be 110 to 130 kg / m 3.

The lower insulation board is formed in the shape of a square having the same width and the same length and is arranged in a plurality of rows and columns in the upper part of the inner wall of the cargo hold and a fixed bolt in which stud bolts are vertically fixed is provided on the central part of the first lower auxiliary panel .

The secondary barrier may be connected to another secondary barrier adjacent to the stud bolt and may form a joint surface welded to the fixing piece at a peripheral portion corresponding to a position where the stud bolt is installed.

The upper heat insulating board may be disposed on both sides of the lower heat insulating board, and may be disposed at an upper portion of the secondary wall in such a manner that corner portions are coupled to the stud bolts.

Wherein an inner hole is formed in each corner of the upper heat insulating board so that a washer and a nut inserted through the inner hole are fastened to the stud bolt protruding toward the inner hole through the first upper auxiliary panel, So that the washer presses the first upper sub-panel.

The cargo hold barrier structure according to the embodiment of the present invention can provide a barrier structure considering the structural strength of the heat insulating board.

Further, as the density of the upper heat insulating member is lowered, the overall heat insulating performance can be improved.

Also, as the density of the upper heat insulating member is lowered, it is possible to reduce the cost.

Further, the upper heat insulating member and the lower heat insulating member can be made of polyurethane foam to improve the heat insulating performance.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the claims.

1 is a perspective view of a vessel cargo hold wall structure according to an embodiment of the present invention.
Fig. 2 is a perspective view of the lower insulation board arrangement of the barrier structure of Fig. 1. Fig.
FIG. 3 is a perspective view illustrating a state in which a secondary barrier is provided on the lower heat-insulating board of FIG. 2. FIG.
FIG. 4 is a perspective view illustrating a state in which an upper heat insulating board is installed on the upper part of the secondary barrier shown in FIG. 3. FIG.
FIG. 5 is a cross-sectional view illustrating a coupling relationship between the upper and lower insulating boards of FIG. 4; FIG.
FIG. 6 is a perspective view illustrating a state in which a connection board is installed between the upper heat insulating boards of FIG.
FIG. 7 is an enlarged view of the upper protection plate and the strip member provided on the upper surface of the connection protection plate shown in FIG.
FIG. 8 is a cross-sectional view of the cargo hold barrier structure of FIG.
Fig. 9 shows another example of the cargo hold barrier structure shown in Fig.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below are provided by way of example so that those skilled in the art will be able to fully understand the spirit of the present invention. The present invention is not limited to the embodiments described below, but may be embodied in other forms. In order to clearly explain the present invention, parts not related to the description are omitted from the drawings, and the width, length, thickness, etc. of the components may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

Referring to FIG. 1, a barrier structure of a vessel cargo hold that stores a cryogenic fluid (e.g., liquefied natural gas (LNG)) according to an embodiment of the present invention includes a lower insulation board 110, a secondary barrier 120, A board 130 and a connection board 135.

The lower insulation board 110 is arranged in a plurality of rows and columns in the upper part of the inner wall of the cargo hold and has a lower protection plate 111, a lower insulation member 112, And a lower sub-panel (113). The lower heat-insulating board 110 may be formed as a unitary unit and arranged side by side on the inner wall of the cargo hold. The lower heat-insulating board 110 may have a predetermined thickness and may have a square shape having the same width and the same length. For example, the lower insulating board 110 may be manufactured to have a size of 1 m having the same length and width.

The lower protection plate 111 may be fixed to the inner wall of the cargo hold by a mastic, a stud bolt or the like. The lower protection plate 111 can be made of, for example, a material such as plywood. The lower heat insulating member 112 is disposed on the lower protective plate 111 and is made of, for example, a reinforced polyurethane foam (R-PUF) to protect the hull from the cryogenic fluid. The lower heat insulating member 112 may be bonded to the upper portion of the lower protective plate 111 by an adhesive (e.g., glue or the like).

Referring to FIG. 2, a fixing piece 210 having a stud bolt 211 vertically fixed is provided on a central portion of the lower sub-panel 113. The fixing piece 210 may be made of a metal material including, for example, stainless steel or the like. The fixing member 210 may be coupled to the coupling groove 113a formed in the lower sub-panel 113 and fixed by a fastening member 2 such as a rivet or the like. The fixing piece 210 may be formed in a circular shape. The lower sub-panel 113 may be made of plywood or the like.

3, the secondary barrier 120 is disposed on the lower insulation board 110 to cover a space formed between the lower insulation boards 110 on both sides of the lower insulation board 110, And are arranged side by side to be connected to the other secondary barrier 120. Although not shown, a filling member such as a glass wool may be inserted into the space formed between the lower heat insulating boards 110. However, the filling member may be omitted when the neighboring lower heat insulating boards 110 are arranged closely to each other or when the lower heat insulating boards 110 are closely bundled to be integrally manufactured.

The secondary barrier 120 forms bonding surfaces 120a and 120b to be welded (W, see FIG. 5) to the fixing pieces 210 of the peripheral portion corresponding to the positions where the stud bolts 211 are installed. At this time, the joining surfaces 120a and 120b may be joined to the fixing piece 210 in a circular welding manner. The joining surfaces 120a formed at both ends of the joining surfaces 120a and 120b form a semicircular groove so that the joining surfaces 120a of the adjacent secondary walls 120 adjacent to the stud bolts 211, And the joint surface 120b formed at the corner may be chamfered and formed obliquely inclined. The periphery of the neighboring secondary barrier 120 can be partially welded to each other with the stud bolt 211 as a center.

In the conventional hold wall structure, the lower insulation board is generally formed in a rectangular shape, and accordingly, the length of welding between the main secondary barrier and the auxiliary secondary barrier is long, There were difficult aspects. The lower insulation board 110 may be manufactured in the above-described manner and disposed above the inner wall of the cargo hold, and the secondary barrier 120 may be disposed thereon by the above-described method. In addition, it is possible to overcome the limitations of conventional barrier arrangements using the primary secondary barrier and the auxiliary secondary barrier, and uniformly install the secondary barrier 120 of a single product easily and efficiently.

The secondary barrier 120 may have a portion 120c covering a space formed between the lower heat insulating boards 110 in a corrugated shape having a downward convex shape. This is to effectively cope with heat shrinkage due to the cryogenic fluid. The secondary barrier 120 may have a lateral length equal to the lateral length of the lower insulating board 110 and a vertical length equal to three times the vertical length of the lower insulating board 110. Through this, the secondary barrier 120 can cover four longitudinally arranged lower heat-insulating boards 110 and two laterally arranged lower heat-insulating boards 110. For example, the secondary barrier 120 may have a length of 1 m and a length of 3 m. The secondary barrier 120 may be composed of a plurality of sheets made of a metal material such as stainless steel, aluminum, brass, zinc, or the like. As another example, a composite sheet made of a metal sheet and a fiber reinforced composite material may be provided.

4, the upper insulation board 130 is interposed between the secondary barrier 120 and the primary barrier (not shown) and includes an upper protection plate 131 and an upper insulation member 132 below the upper protection plate 131 . The upper insulating board 130 may have a predetermined thickness and may have the same length and width. In addition, the upper heat insulating board 130 may be formed in the same shape and size as the lower heat insulating board 110.

The upper protection plate 131 may be made of a material such as plywood. The upper insulating member 132 may be made of, for example, a reinforced polyurethane foam to protect the hull from the cryogenic fluid. The primary barrier described above is in direct contact with the cryogenic fluid and can be made of a metal material such as stainless steel (SUS) or the like. The upper insulating board 130 is disposed on the lower insulating board 110 on both sides and is disposed at a predetermined interval on the secondary barrier 120 in such a manner that the corner portions are coupled to the stud bolts 211 . As shown in FIG. 4, the upper heat insulating board 130 covers two lower heat insulating boards 110 on both sides, and each corner is connected to the stud bolts 211 of the lower heat insulating board 110 . Accordingly, the space formed between the lower insulating boards 110 is covered by the upper insulating board 130, thereby preventing the leakage of the cryogenic fluid and improving the heat insulating effect.

5, the upper insulating board 130 includes an upper auxiliary panel 134 interposed between the upper insulating member 132 and the secondary barrier 120, an upper auxiliary panel 134 and a secondary barrier 120 To protect the cargo barrier walls from sloshing shocks caused by liquefied gas stored in the interior of the cargo hold. The shock absorbing layer 133 may be omitted in another example. The upper sub-panel 134 may be made of plywood or the like. The shock absorbing layer 133 may be made of, for example, melamine foam as a foam material. Melamine foam is an open type foam based on amino resin type melamine resin, which not only absorbs impact but also has excellent heat insulation performance. However, the present invention is not limited to this, and the shock absorbing layer 133 may be made of various materials capable of protecting the cargo barrier from the sloshing shock caused by the liquefied gas stored in the cargo hold. The upper insulating board 130, the upper auxiliary panel 134, and the impact absorbing layer 133 may be integrally formed.

Each of the corners of the upper insulating board 130 is formed with an inner hole 130a so that the washer 212 and the nut 213 inserted through the inner hole 130a are inserted into the impact absorbing layer 133 and the upper auxiliary panel 134, And the washer 212 presses the upper sub-panel 134 by tightening the nut 213. The nut 213 is fastened to the stud bolt 211 protruding toward the inner hole 130a through the through- A plug member (not shown) filled with foam or the like may be disposed in the inner hole 130a and may be finished by a cover (not shown) made of plywood or the like.

Referring to FIG. 6, the connection board 135 is interposed in a space formed between the upper heat insulation boards 130. Thereby, a space formed between the lower heat insulating boards 110, which is not covered by the upper insulating board 130, is covered by the connecting board 135. The connection board 135 is sandwiched between the upper insulation boards 130 and bonded to the neighboring upper insulation board 130 by an anchor plate 150 to be described later. The connection board 135 is sandwiched between the upper heat insulation boards 130 in a form of covering two lower insulation boards 110 on both sides. FIG. 6 shows a state in which the understanding connecting board 135 is not completely filled. The state in which the connection board 135 has been installed is described above with reference to FIG.

The connection board 135 includes a connection protection plate 136 and a connection insulation member 137 below the connection protection plate 136 so as to be coplanar with the upper insulation board 130. Although not shown, when the upper heat insulating board 130 further includes the shock absorbing layer 133 and the upper sub-panel 134 so that the connecting board 135 is coplanar with the upper insulating board 130, And may further include corresponding members respectively. At this time, each member may be made of the same material and thickness as the impact absorbing layer 133 and the upper sub-panel 134.

The connection protection plate 136 and the connection insulation member 137 may be made of the same material as the upper protection plate 131 and the upper insulation member 132, respectively. At this time, the upper insulating board 130 and the connecting board 135 are inserted into grooves formed on one side surface of the upper insulating board 130 and one side of the connecting board 135. Either one of the opposite ends is fixed and the other is connected to the upper insulating board 130 and the connecting board 135 An anchor plate 150 may be provided to bind the upper insulating board 130 and the connecting board 135 in a manner to press one of them. For example, when one side of the anchor plate 150 is coupled to the upper heat insulating board 130 by a fastening member such as a rivet or the like, the other side of the anchor plate 150 presses the neighboring connecting board 135.

6 and 7, strip members 160 and 161 are provided in grooves formed in the upper protection plate 131 and the connection protection plate 136 so as to be movable in accordance with the expansion and contraction of the primary barrier. 7 (a) and 7 (b) show a state in which the strip members 160 and 161 are fastened to the grooves formed in the upper protective plate 131 for the convenience of explanation. A primary barrier is disposed above the strip members 160 and 161 and a fixed strip member 161 disposed at the center of the upper protective plate 131 may be fixed so as not to be slid. The other strip member 160 is supported by the auxiliary plate 165 in which the fastening member 2 is fastened through the through hole H1 in such a manner that both ends of the strip member 160 are pressed from above, And can be slid according to the movement of the primary barrier which expands and contracts. At this time, the primary barrier is installed in such a manner as to press the upper part of the slidably installed strip member 160, so that the strip member 160 can slide together with the contraction expansion of the primary barrier. The strip members 160 and 161 may be made of, for example, stainless steel or the like. A binding member (not shown) such as a bolt or the like is fastened to the thread hole H2 of the auxiliary plate 165. When the wall of the cargo hold is installed in the longitudinal direction, the strip member 160, The strip member 160 can be temporarily fixed so as not to slide downward by a load.

Meanwhile, the barrier structure of the cargo hold according to the embodiment of the present invention can be configured in consideration of the structural strength of the upper and lower heat insulating boards. When the cryogenic fluid such as LNG is loaded in the cargo hold, the temperature changes from -163 ° C to -62 ° C to + 45 ° C from the inside of the hold to the secondary barrier and the vicinity of the hull, The mechanical properties of the urethane foam are such that the mechanical strength increases as the temperature is lowered. The structural strength of the upper insulation board at the time of loading LNG is increased to about twice the structural strength of the lower insulation board so that the density of the upper insulation board can be made lower than that of the lower insulation board. As a result, the cost of the upper heat insulating member can be reduced, and the heat insulating performance can be improved as the density of the upper heat insulating member is lowered. Hereinafter, a concrete explanation will be given based on Fig. For reference, FIG. 8 is a simplified illustration of the barrier structure shown in FIG. 5 for better understanding; the shock absorbing layer 133 of FIG. 5 and unnecessary elements for convenience of explanation are omitted.

8, the upper heat insulating member 132 and the lower heat insulating member 112 may be made of a reinforced polyurethane foam, and the upper heat insulating member 132 may be manufactured to have a lower density than the lower heat insulating member 112 . At this time, the density of the upper heat insulating member 132 may be 90 to 110 kg / m 3, and the density of the lower heat insulating member 112 may be 110 to 130 kg / m 3.

The upper protection plate 131, the first upper auxiliary panel 134, the lower protection plate 111, and the lower protection plate 132 are formed in a state where the upper insulation member 132 is manufactured at a lower density than the lower insulation member 112, The first lower sub-panel 113 may be made of plywood.

As another example, the upper heat insulating member 132 may be made of a reinforced polyurethane foam and the lower heat insulating member 112 may be made of a polyurethane foam. Similarly, the upper heat insulating member 132 has a density lower than that of the lower heat insulating member 112, the density of the upper heat insulating member 132 is 90 to 110 kg / m 3, the density of the lower heat insulating member 112 is 110 to 130 kg / M < 3 >. At this time, the upper protection plate 131, the first upper auxiliary panel 134, and the lower protection plate 111 may be made of plywood.

Since the lower heat insulating member 112 is made of polyurethane foam, the first lower sub-panel 113 may be formed of a material other than the plywood, for the purpose of mitigating the thermal stress between the first lower auxiliary panel 113 and the lower heat insulating member 112. [ And may be made of one or more of glass fiber reinforced plastics (FRP), aluminum (AL), and stainless steel (SUS).

Referring to FIG. 9, the upper insulating member 132 and the lower insulating member 112 may be made of polyurethane foam. In the case of reinforced polyurethane foam prepared by appropriately adding glass fiber (CSM, Continuous Strand Mat) to polyurethane foam (PUF, PolyurethaneFoam) for improving tensile properties, the thermal properties (thermal conductivity) . When a polyurethane foam is used, the manufacturing cost of the upper heat insulating member 132 and the lower heat insulating member 112 is reduced and the heat insulating performance is improved.

At this time, the upper protection plate 131 may be made of glass fiber reinforced plastic. Normally, the upper protection plate 131 is made of plywood, but made of glass fiber reinforced plastic through the embodiment of the present invention. This is because the upper thermal insulating member 132 and the lower thermal insulating member 112 are made of polyurethane foam due to the excellent mechanical properties of the glass fiber reinforced plastic (material) and the thermal properties (thermal expansion coefficient 2 to 2.5 times higher than that of the flywood) This is because it can be produced effectively.

The lower protection plate 111 and the first upper auxiliary panel 134 may be made of one or more of glass fiber reinforced plastic, aluminum (AL), stainless steel (SUS), and plywood.

Since the lower heat insulating member 112 is made of polyurethane foam, the first lower sub-panel 113 may be formed of a material other than the plywood, for the purpose of mitigating the thermal stress between the first lower auxiliary panel 113 and the lower heat insulating member 112. [ Glass fiber reinforced plastic, aluminum (AL), and stainless steel (SUS).

The upper insulation board 130 includes a second upper auxiliary panel 138 interposed between the first upper auxiliary panel 134 and the secondary barrier 120 and a third upper auxiliary panel 138 disposed above the upper protective plate 131. [ (139).

The lower insulation board 110 includes a second lower sub-panel 114 interposed between the second barrier 120 and the first lower sub-panel 113 and a third lower sub- (115). The second upper sub-panel 138, the third upper sub-panel 139, the second lower sub-panel 114, and the third lower sub-panel 115 may be made of a plywood material. In the embodiment of the present invention, a glass fiber reinforced plastic or the like having a thermal expansion coefficient higher than that of plywood is used for a polyurethane foam having excellent heat insulating performance as a heat insulating member. At this time, it is possible to apply the glass fiber reinforced plastic alone, but since the unit cost of the material can be increased, the glass fiber reinforced plastic and the plywood can be applied together with the minimized thickness.

The foregoing has shown and described specific embodiments. However, it is to be understood that the present invention is not limited to the above-described embodiment, and various changes and modifications may be made without departing from the scope of the technical idea of the present invention described in the following claims It will be possible.

110: lower insulation board 111: lower protection board
112: lower insulation member 113: lower sub-panel
114: second lower sub-panel 115: third lower sub-panel
120: secondary barrier 130: upper insulation board
131: upper protection plate 132: upper insulation member
133: shock absorbing layer 134: upper auxiliary panel
135: connection board 136: connection board
137: connection heat insulating member 138: second upper auxiliary panel
139: third upper auxiliary panel

Claims (12)

An upper heat insulating board disposed at a lower portion of the primary barrier and including an upper insulating plate and an upper insulating member on a lower surface thereof;
A secondary barrier disposed below the upper insulating member; And
And a lower insulation board disposed below the secondary barrier and including a lower insulation member and a lower protection plate on the lower surface thereof,
Wherein the upper heat insulating member has a lower density than the lower heat insulating member. The method according to claim 1,
Wherein the heat insulating member is made of a reinforced polyurethane foam and the lower heat insulating member is made of reinforced polyurethane foam or polyurethane foam. 3. The method of claim 2,
Wherein the upper insulating board further comprises a first upper sub-panel interposed between the upper insulating member and the secondary barrier,
Wherein the lower insulation board further comprises a first lower sub-panel interposed between the secondary barrier and the lower insulation member,
Wherein the upper protection plate, the first upper auxiliary panel and the lower protection plate are made of plywood,
When the lower heat insulating member is made of reinforced polyurethane foam, the first lower sub-panel is made of plywood,
Wherein the first lower sub-panel is made of one or more of glass fiber reinforced plastic, aluminum and stainless steel when the lower heat insulating member is made of polyurethane foam. The method according to claim 1,
Wherein the upper and lower thermal insulation members are made of polyurethane foam. The method according to claim 1,
The upper protection plate is made of glass fiber reinforced plastic,
The bottom protection plate is made of one or more of glass fiber reinforced plastic, aluminum, stainless steel and plywood. The method according to claim 1,
Wherein the upper insulating board further comprises a first upper auxiliary panel interposed between the upper insulating member and the secondary barrier,
Wherein the lower insulation board further comprises a first lower sub-panel interposed between the secondary barrier and the lower insulation board,
Wherein the first upper sub-panel is made of at least one of glass fiber reinforced plastic, aluminum, stainless steel and plywood,
Wherein the first lower sub-panel is made of one or more of polyurethane foam, aluminum and stainless steel. The method according to claim 6,
The upper insulating board further comprises a second upper sub-panel interposed between the first upper sub-panel and the secondary barrier, and a third upper sub-panel disposed above the upper protective plate,
The lower insulation board further includes a second lower sub-panel interposed between the secondary barrier and the first lower sub-panel, and a third lower sub-panel disposed below the lower protection plate,
Wherein the second upper sub-panel, the second lower sub-panel, the third upper sub-panel, and the third lower sub-panel are made of a plywood material. The method according to claim 1,
The density of the upper heat insulating member is 90 to 110 kg / m 3, and the density of the lower heat insulating member is 110 to 130 kg / m 3. The method according to claim 3 or 6,
The lower insulation board is formed in the shape of a square having the same width and the same length, is arranged in a plurality of rows and columns in the upper part of the inner wall of the cargo hold,
And a securing piece having a vertically fixed stud bolt is provided on a central portion of the first lower sub-panel. 10. The method of claim 9,
Wherein the secondary barrier is connected to another secondary barrier adjacent to the stud bolt, and a joint surface welded to the fixing piece is formed at a peripheral portion corresponding to a position where the stud bolt is installed. 10. The method of claim 9,
Wherein the upper heat insulating board is disposed on both sides of the lower heat insulating board and is arranged at a predetermined interval on the upper part of the secondary barrier in such a manner that the corner portions are coupled to the stud bolts. 10. The method of claim 9,
Wherein an inner hole is formed in each corner of the upper heat insulating board so that a washer and a nut inserted through the inner hole are fastened to the stud bolt projected toward the inner hole through the first upper auxiliary panel, Wherein the washer presses the first upper sub-panel.

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