KR20170050589A - Insulation System For Membrane Type in LNG Storage Tank - Google Patents

Abstract

The present invention relates to an insulation system of a liquefied gas cargo hold. The present invention sets a thickness of a primary insulation layer to be less than 10% of the thickness of a secondary insulation layer and has a cross-shaped fixing unit fixating a membrane and the primary insulation layer together to improve a fixing structure of the primary insulation layer and a sealing structure of the membrane in order to reduce the weight of a cargo hold and slim down the cargo hold and maintain structural strength and insulation property. Moreover, a manufacturing process of the cargo hold is simplified to improve workability and reduce production costs.

Description

TECHNICAL FIELD [0001] The present invention relates to an insulation system for a liquefied gas storage tank,

The present invention relates to a heat insulating system for a liquefied gas holding window, and more particularly to a heat insulating system of a liquefied gas holding window, in which the thickness of the primary insulating layer is set to 10% or less of the thickness of the secondary insulating layer, The present invention relates to an insulation system for a liquefied gas holding window in which a membrane and insulation securing unit is installed to improve the fixing structure of the primary insulating layer and the membrane sealing structure.

In general, natural gas is transported in a gaseous state through land or sea gas pipelines, or transported to a remote location where it is stored in an LNG carrier in the form of liquefied natural gas (hereinafter abbreviated as LNG) .

LNG is obtained by cooling natural gas to about -163 ° C at a very low temperature, and its volume is reduced to about 1/600 of that of natural gas, making it well suited for long distance transportation through the sea.

LNG carriers for loading LNG to the sea by loading LNG, LNG carriers for loading LNG, and LNG RV (regasification vessel) for recharging the stored LNG after unloading to natural gas, Is equipped with a cryogenic storage tank, i.e., a cargo hold, of liquefied natural gas.

Recently, there is a growing demand for floating floating structures such as LNG FPSO (floating, production, storage and offloading) and LNG FSRU (floating storage and regasification unit). LNG carrier or LNG RV A cargo hold to be installed is provided.

LNG FPSO is a floating marine structure that is used to liquefy the produced natural gas directly from the sea and store it in the cargo hold, and to transfer the LNG stored in the cargo hold to the LNG carrier if necessary.

LNG FSRU is a floating floating structure that stores LNG unloaded from an LNG cargo vessel in the sea off the sea, and then vaporizes LNG if necessary to supply it to the customer.

LNG carriers such as LNG carriers, LNG RVs, LNG FPSOs, and LNG FSRUs, which transport or store liquids such as LNG, are installed in storage structures to store LNG in cryogenic conditions.

Cargo holds can be classified into independent tanks and membrane types depending on whether the cargo load directly acts on the insulation.

Typically, the membrane type cargo holds are divided into GTT NO 96 type and TGZ Mark III type, and the independent tank type cargo hold is divided into MOSS type and IHI-SPB type.

The membrane-type cargo holds have different insulation and structure depending on the type of special metal plate. The GTT NO96 type uses a thin sheet of invar (Invar - a material with a very small thermal expansion coefficient which is mainly composed of iron and nickel) Use a thin sheet of material.

The GTT NO 96 type cargo hold is composed of a first membrane and a second membrane made of Invar steel having a thickness of 0.5 to 1.5 mm, a first insulating wall made of a plywood box and a perlite, Are alternately stacked and installed inside the hull.

The insulation system of the GTT NO 96 type cargo holds is composed of two layers of insulating steel box (36% nickel steel) and pearlite and plywood wood, and the plywood is used as the material of the insulation box.

A conventional insulation system for a liquefied gas holding window will be described below.

A conventional insulation system of a liquefied gas holding window comprises a primary membrane and a secondary membrane made of invar steel having a thickness of 0.5 to 0.7 mm; A primary insulation layer and a secondary insulation layer made of a plywood box and perlite; A heat insulating layer fixing unit for fixing the primary heat insulating layer and the secondary heat insulating layer; And a membrane fixing part for fixing the primary membrane and the secondary membrane.

1 is a sectional view showing a membrane fixing unit in a conventional insulation system.

Referring to FIG. 1, a membrane securing unit in a conventional insulation system has a tongue fixing groove 1a formed in a heat insulating layer.

The lower end of the membrane fixing tongue 3 is inserted into the tongue fixing groove 1a and the upper end of the membrane fixing tongue 3 protrudes upward from the heat insulating layer.

A position adjusting hole 3a is formed at an upper end of the membrane tongue 3. A membrane 4 is laminated on the upper surface of the insulating layer 1 and the membrane 4 is seam welded to the membrane tongue 3. The position adjusting hole 3a is used to adjust the level of the membrane 4 by moving the membrane tongue 3 upward and downward.

However, in the conventional heat insulation system of the liquefied gas holding window, there is a problem that workability is poor because a separate height adjustment work is required to adjust the level of the membrane 4 during the membrane sealing welding operation.

In addition, due to the technical limitations of maintaining a certain thickness without reducing the thickness of the heat insulating layer in order to maintain the heat insulating performance of the heat insulating layer, the manufacturing workability of the heat insulating system of the cargo hold is lowered and the manufacturing cost is increased.

U.S. Patent No. 6,035,795 U.S. Published Patent Application No. 2003-0000949 Korean Patent Publication No. 10-2000-0011347 Korean Patent Publication No. 10-2000-0011346

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a membrane and insulation securing unit in which the thickness of the primary insulation layer is set to 10% or less of the thickness of the secondary insulation layer, unit is installed to improve the fixing structure of the primary insulation layer and the membrane sealing structure, it is possible to maintain the structural rigidity and insulation performance while realizing the light weight and slimness, as well as to improve the workability by simplifying the manufacturing process of the cargo hold, And an object of the present invention is to provide an insulation system for a liquefied gas holding window that can be reduced.

In order to accomplish the above object, the present invention provides a heat insulation system for a liquefied gas holding window, comprising: a secondary insulation layer for secondary insulation of a cargo hold with respect to an inner wall of a hull; A secondary membrane of an invar steel material disposed on the secondary insulation layer; A primary insulation layer disposed over the secondary membrane to primarily insulate the cargo hold; A primary membrane of an invar steel material disposed on the primary heat insulating layer; A first securing unit for securing the primary membrane, the secondary membrane, and the primary insulation layer; And a second fixing unit fixing the secondary insulation layer by setting spring constants differently according to deformation conditions of the inner wall of the hull of the cargo hold.

The heat insulating system of the present invention is laminated in order from the inner wall of the hull (the inner wall of the tank), the secondary insulation layer, the secondary membrane, the primary insulation layer, and the primary membrane.

The thickness of the first heat insulating layer may be less than 10% of the thickness of the second heat insulating layer. The first fixing unit is provided between the boundary portions between the primary heat insulating layers and the slit of the secondary heat insulating layer.

Wherein the first fixing unit is inserted between the boundary portions of the first heat insulating layer and the slit of the second heat insulating layer and is positioned vertically and the end portion is positioned to protrude relative to the second heat insulating layer; A first fixing part fixed to both sides of the vertical unfolded member and inserted into the slit and a second fixing part fixed to the secondary heat insulating layer after being bent in the horizontal direction from the first fixing part, Shaped second bending member; A second fastening member fastened in a fastening hole formed in the second fastening portion of the "L" -shaped second bending member to fix the "L" -shaped second bending member to the second heat insulating layer; L "-shaped first bending portion composed of a first fixing portion fixed to both sides of the vertical unfolded member, and a second fixing portion formed in a horizontal direction from the first fixing portion and then fixed to the first heat insulating layer absence; And a first fastening member fastened in a fastening hole formed in the second fastening portion of the "L" -shaped first bending member to fix the "L" -shaped first bending member to the first heat insulating layer .

L "-shaped second folding member is placed in the stepped groove, a stepped groove is formed in the first heat insulating layer and the" L "-shaped groove is formed in the stepped groove, And the second fixing portion of the first bent-like member can be seated.

The first fixing portion of the " L "-shaped second bending member is bent into the slit and is sewn-welded to the vertical unfolded member, and the first fixing portion of the" L & And then sewn to the vertical unfolded member.

The secondary membrane may be welded to the second fixed portion of the " L "shaped second bending member or sewn welded to the vertical unfolded member of the" L "shaped second bending member.

The primary membrane may be welded to the second fixed portion of the " L "shaped first bending member or welded to the first fixed portion of the" L "shaped first bending member.

And a chamfered portion for preventing interference with the "L" -shaped second bending member is formed at an edge of the upper end of the secondary heat insulating layer, and a chamfer for preventing interference with the primary membrane is formed at the lower end corner of the primary heat insulating layer. An additional portion may be formed.

The secondary insulation layer fixing unit includes a stud bolt fixed to the inner wall of the hull on which the secondary insulation layer is installed; A nut fastened to the stud bolt for securing the secondary heat insulating layer; An elastic body that is fitted to the stud bolt and adjusts the elasticity according to the degree of deformation of the inner wall of the hull of the secondary heat insulating layer; A compression fixing mold which is sandwiched between the stud bolts and laminated on the elastic body to prevent local damage of the secondary insulation layer; And a reference plate for height adjustment according to the degree of deformation of the inner wall of the hull of the secondary insulation layer.

A filling plug may be installed in a space between the secondary insulation layers located above the compression fixing mold.

As described above, the thickness of the primary insulation layer is set to 10% or less of the thickness of the secondary insulation layer, and a membrane and insulation securing unit capable of fixing the membrane and the primary insulation layer together is installed By improving the fixing structure of the cold insulating layer and the membrane sealing structure, it is possible to maintain the structural rigidity and heat insulating performance while realizing weight saving and slimness, and also the manufacturing process of the cargo hold can be simplified, and workability can be improved and production cost can be drastically reduced.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view of a membrane-
2 is a perspective view showing a heat insulating system of a liquefied gas holding window according to the present invention.
3 is a vertical sectional view showing the first fixing unit in the adiabatic system of the liquefied gas holding window according to the present invention
4 is a longitudinal sectional view showing the second fixing unit in the adiabatic system of the liquefied gas holding window according to the present invention

Hereinafter, a heat insulating system of a liquefied gas holding window according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a longitudinal sectional view showing a first fixing unit in the adiabatic system of a liquefied gas holding window according to the present invention, and Fig. 4 is a longitudinal cross-sectional view showing a liquefied gas holding window according to the present invention. Fig. 2 is a perspective view showing the adiabatic system of the liquefied gas holding window according to the present invention, Sectional view showing a second fixing unit in a heat insulating system of a gas holding window.

2 to 4, an adiabatic system according to the present invention includes a secondary insulation layer 130, a secondary membrane 140, a primary insulation layer 110, a primary membrane 120, securing 150, and a securing securing 170.

The secondary membrane 140, the primary insulating layer 110, and the primary membrane 120 are disposed (laminated) from the reference inner wall (see FIG. 1) in the order of the secondary insulating layer 130, the secondary insulating membrane 110, and the primary membrane 120.

The secondary insulation layer 130 serves to thermally insulate the cargo hold and is fixed at a predetermined distance from the inner wall 1 of the hull with a resin (not shown) interposed therebetween. The secondary insulation layer 130 may be formed of a glass fiber reinforced polyurethane foam or a sandwich of plywood, insulation, and composite structures.

The secondary membrane 140 is made of Invar steel and is sealed welded onto the secondary insulation layer 130. The welding method is either lapping welding or seam welding.

The primary insulation layer 110 serves to primarily insulate the cargo hold, and is fixed at a position covering the secondary membrane 140.

The primary insulation layer 110 and the secondary insulation layer 130 have different cross-sectional areas and heights. The width of the primary heat insulating layer may be ½ of the secondary heat insulating layer, and the length of the secondary heat insulating layer may be double.

The thickness of the first heat insulating layer 110 may be less than 10% of the thickness of the second heat insulating layer 130, preferably 5-10%.

The present invention can improve the fixing structure of the primary heat insulating layer and the membrane sealing structure by maintaining the strength of the primary heat insulating layer and minimizing the thickness of the primary heat insulating layer.

The primary insulation layer 110 may be formed by a single structure in which a plurality of plywoods are laminated in the thickness direction or a plurality of laminated plywoods and a heat insulating material such as glass wool and a low density polyurethane foam having a density of 40 to 50 kg / And a composite structure composed of a heat insulating material.

The primary membrane 120 is made of Invar steel and is sealed welded onto the primary insulation layer 110. The welding method is both lapping welding and sealing welding.

The first fixing unit 150 serves to fix the primary membrane 120, the secondary membrane 140, and the primary insulation layer 110 together. The primary fixing unit 150 can be made of an invar steel material, .

The second fixing unit 170 serves to fix the secondary insulation layer 130 by setting spring constants differently according to the deformation conditions of the inner wall 1 of the hull of the cargo hold.

Hereinafter, the configuration of the first fixing unit 150 will be described in detail with reference to FIG.

The first fixing unit 150 is installed between the boundary between the primary insulation layers 110 and in the slit S of the secondary insulation layer 130. The slit of the secondary insulation layer is a groove formed in the insulation layer in order to prevent deformation due to the difference in the expansion ratio between the plywood and the insulation.

The first fixing unit 150 includes a vertical unfolding member 151, an L-shaped second bending member 152, a second fastening member 153, an L-shaped first bending member 154, 1 fastening member 155 as shown in FIG.

The vertical unfolded members 151 are inserted into the slits S of the secondary insulation layer 130 and vertically positioned between the boundary portions between the primary insulation layers and positioned such that the upper ends of the vertical unfolded members 151 protrude relative to the primary insulation layer 110. Here, the expression of the upper end portion is described on the basis of FIG. 3, and the expression of the upper side may be changed to the lower side or the side depending on the position of the cargo hold.

The "L" -shaped second folding member 152 has a shape bent in an "L" shape and is fixed to both sides of the vertical unfolded member 151. The first and second fixing members 152a and 152b ). Here, the description of the first fixing portion 152a and the second fixing portion 152b is merely arbitrarily set for the sake of convenience of explanation, and therefore, it is not necessarily divided into two portions, Of course.

The first fixing part 152a may be inserted into the slit S and sewn welded to the vertical unfolded member 151 and fixed. The second fixing part 152b is bent in the horizontal direction from the first fixing part 152a and fixed to the secondary heat insulating layer 130. [ A stepped groove 130a is formed in the secondary heat insulating layer 130 and the second fixing portion 152b of the second L-shaped bent member 152 is seated in the stepped groove 130a. The reason for placing the stepped groove 130a is that the level of the second fixing portion 152b and that of the second heat insulating layer 130 are made the same so that the secondary membrane 140 is welded flatly by sealing.

The second fixing portion 152b is formed with a fastening hole H in which a second fastening member 153 such as a rivet or a bolt is fastened.

The secondary membrane 140 may be welded to the second fixed portion 152b of the " L "shaped second bending member 152 or sewn welded to the vertical unfolded member 151. [

A chamfer 130b for preventing interference with the "L" -shaped second bending member 152 may be formed at an edge of the upper end of the secondary heat insulating layer 130. [

The first L-shaped first bending member 154 has a shape bent in an L shape and is fixed to both sides of the vertical unfolded member 151. The first L-shaped first bending member 154 and the second L- (154b).

The first fixing portion 154a is welded and fixed to both sides of the vertical unfolded member 151. [ The first fixing portion 151a can be welded upward. The second fixing portion 154b is bent in the horizontal direction from the first fixing portion 154a and fixed to the primary heat insulating layer 110. [ The first heat insulating layer 110 is formed with a stepped groove 110a and a second fixing portion 154b of the first L-shaped bent member 154 is seated in the stepped groove 110a. The reason for placing the stepped groove 110a is that the level of the second fixing portion 154b and that of the primary heat insulating layer 110 are made the same so that the primary membrane 120 is welded flatly by sealing. The second fixing portion 154b is formed with a fastening hole H in which the first fastening member 155, for example, a rivet or a bolt is fastened.

The primary membrane 120 may be welded to the second fixed portion 154b of the " L "first bending member 154 or sewn welded to the vertical unfolded member 151. [

A chamfer 110b for preventing interference with the "L" -shaped second folding member 152 may be formed at the lower edge of the first heat insulating layer 110. [

Hereinafter, the configuration of the second fixing unit 170 will be described in detail with reference to FIG.

Referring to FIG. 4, the adiabatic system according to the present invention includes a secondary insulation securing 170.

The secondary insulation securing 170 can be fixed by setting different spring constants according to the deformation conditions of the inner wall 1 of the hull of the cargo hold. For example, the stud bolt A nut 171, a nut 172, an washer spring 173, a compression fixture mold 174, and a reference wedge 175.

In other words, the stud bolt 171 is fixed to the inner wall 1 of the hull where the secondary insulation layer 130 is installed. The fixing method of the stud bolt 171 can be fixed by a usual fastening means, for example, welding.

A nut 172 is fastened to the stud bolt 171 for securing the secondary insulation layer 130.

The washer spring 173 is fitted in the stud bolt 171 and is configured to adjust the elasticity of the secondary insulation layer 130 in accordance with the degree of deformation of the inner wall 1 of the hull. For elasticity control, the elastic body 173 may be replaced with a three-stage or five-stage.

The compression fixing mold 174 is configured to be laminated on the elastic body 173 by being fitted in the stud bolt 171 to prevent local damage of the secondary insulation layer 130. High density PUF, compressed wood and the like can be used.

A reference wedge 175 is fixed to the hull inner wall 1 and a stud bolt 171 is vertically fixed to the reference plate 175. The reference plate 175 is configured to adjust the height according to the degree of deformation of the inner wall 1 of the secondary insulation layer 130.

The filling plug 176 is provided at an upper portion of the compression fixing mold 174 and the filling plug 176 fills the through hole H where the stud bolt 171 is provided to prevent the secondary heat insulating layer 130 from being damaged .

In the insulation system of the liquefied gas holding window constructed as described above, the thickness of the primary insulation layer 110 is set to 10% or less of the thickness of the secondary insulation layer 130, and the width of the primary insulation layer is divided into two, A first fixing unit, which is a cross-type invar connection, is provided between the slit of the secondary insulation layer and the boundary between the primary insulation layer to fix the primary membrane, the secondary membrane, and the primary insulation layer together It is possible to maintain the structural rigidity and the heat insulation performance while realizing the light weight and slimness, and also the manufacturing process of the cargo hold is simplified, thereby improving the workability and drastically reducing the production cost.

In the adiabatic system of the present invention, after the first bending member is fixed to the first heat insulating layer relatively thinner than the second heat insulating layer with a rivet or a screw, And a temporary fixing method in which the first bending member is temporarily fixed to the first heat insulating layer and then the second bending member is sealed and welded to the second bending member.

In the adiabatic system of the present invention, since the edges of the vertical unfolded members in the continuous installation direction are sealed-welded to the primary and secondary membranes, the sealing operation is very easy since no separate height adjustment is required at the time of welding for sealing the membrane, There is an advantage that the property is improved.

In the adiabatic system of the present invention, when the secondary membrane is sealed by welding, it can be used as a fixing point for sealing welding with adjacent membranes, and there is no need for a fixing structure penetrating the secondary membrane for installing and fixing the primary heat insulating layer, Due to the relatively thin primary insulating layer, it is possible to fix using the first fixing unit which is the cross-shaped connecting structure of the present invention.

4, in the adiabatic system according to the preferred embodiment of the present invention, the secondary insulation securing 170 is designed to have a spring constant according to the deformation condition of the hull inner wall 1 of the cargo hold, Can be set and fixed differently.

That is, in order to adjust the elasticity, the elastic body 173 can be appropriately changed according to the design conditions in three stages or five stages. The reference wedge 175 is fixed to the inner wall 1 of the hull and the stud bolt 171 is vertically fixed to the reference plate 175. The reference bolt 171 is fixed to the hull inner wall 1 of the secondary insulation layer 130, The height can be adjusted according to the degree of deformation. Although not shown in the drawing, the reference wedge 175 may be integrally formed with the stud bolt 171.

As described above, according to the present invention, the thickness of the primary insulation layer is set to 10% or less of the thickness of the secondary insulation layer, and a cross-shaped fixing unit capable of fixing the membrane and the primary insulation layer together and insulation securing unit are installed to improve the fixing structure of the primary insulation layer and the membrane sealing structure to realize a lightweight and slimmer structure while maintaining the structural rigidity and heat insulation performance as well as simplifying the manufacturing process of the cargo hold The production cost can be greatly reduced.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Various modifications and variations are possible within the scope of equivalents. For example, the adiabatic system of the present invention is not limited to a cargo hold of a liquefied gas carrier and may be equally applicable to both storage tanks for storing liquefied gas.

In the description of the present invention, the upper side is described with reference to Fig. 5 on the side of the bottom roof tundish bulkhead. Due to the characteristics of the cargo hold, the lower side or the side surface can be changed depending on the position of the cargo hold.

1: inner hull
110: primary insulating layer
110a:
110b: chamfer
120: primary membrane
130: secondary insulation layer
130a:
130b:
140: Secondary membrane
150: first securing unit (first securing unit)
151: vertical unfolded member
152: "L" -shaped second bending member
152a:
152b:
153: second fastening member
154: "L" -shaped first bending member
154a:
154b:
155: first fastening member
170: Secondary insulation layer fixing unit
171: stud bolt
172: nut
173: Elastomer
174: Mold for fixing compression
175: reference wedge
176: Filling plug
H: fastening hole
S: Slit

Claims (10)

A secondary insulation layer for secondary insulation of the cargo hold with respect to the inner wall of the hull;
A secondary membrane of an invar steel material disposed on the secondary insulation layer;
A primary insulation layer disposed over the secondary membrane to primarily insulate the cargo hold;
A primary membrane of an invar steel material disposed on the primary heat insulating layer;
A first securing unit for securing the primary membrane, the secondary membrane, and the primary insulation layer; And
And a second fixing unit for fixing the secondary insulation layer by setting a spring constant differently according to deformation conditions of the inner wall of the hull of the cargo hold. The method according to claim 1,
Wherein the thickness of the primary insulation layer is less than 10% of the thickness of the secondary insulation layer. The method according to claim 1,
Wherein the first fixing unit is installed between the boundary portions between the primary heat insulating layers and in the slits of the secondary heat insulating layer. The method of claim 3,
The first fixed unit
A vertical unfolded member inserted between the boundary portions of the primary heat insulating layers and vertically inserted into the slits of the secondary heat insulating layer and positioned such that the end portions thereof protrude relatively to the secondary heat insulating layer;
A first fixing part fixed to both sides of the vertical unfolded member and inserted into the slit and a second fixing part fixed to the secondary heat insulating layer after being bent in the horizontal direction from the first fixing part, Shaped second bending member;
A second fastening member fastened in a fastening hole formed in the second fastening portion of the "L" -shaped second bending member to fix the "L" -shaped second bending member to the second heat insulating layer;
L "-shaped first bending portion composed of a first fixing portion fixed to both sides of the vertical unfolded member, and a second fixing portion formed in a horizontal direction from the first fixing portion and then fixed to the first heat insulating layer absence; And
And a first fastening member fastened in a fastening hole formed in the second fixing portion of the "L" -shaped first bending member to fix the "L" -shaped first bending member to the first heat insulating layer. Of the insulation system. The method of claim 4,
A stepped groove is formed in the secondary heat insulating layer and the second fixing portion of the "L" -shaped second bending member is seated in the stepped groove,
Wherein the first insulating layer is formed with a stepped groove and the second fixing portion of the "L" -shaped first bending member is seated in the stepped groove. The method of claim 4,
The first fixing portion of the "L" -shaped second bending member is bent into the slit and is sewn-welded to the vertical unfolded member,
Wherein the first fixing portion of the "L" -shaped first bending member is bent toward the liquefied gas side, and is then sewn-welded to the vertical unfolded member. The method of claim 4,
Characterized in that the secondary membrane is welded to the second fixed portion of the " L "-shaped second bending member or is sewn-welded to the vertical unfolded member of the" L & Of the insulation system. The method of claim 4,
Characterized in that the primary membrane is welded to the second fixed portion of the " L "shaped first bending member or welded to the first fixed portion of the" L "shaped first bending member. Of the insulation system. The method of claim 4,
And a chamfered portion for preventing interference with the "L" -shaped second bending member is formed at an edge of the upper end of the secondary heat insulating layer, and a chamfer for preventing interference with the primary membrane is formed at the lower end corner of the primary heat insulating layer. Wherein the liquefied gas in the liquefied gas storage chamber is formed in an annular shape. The method according to claim 1,
The secondary insulation layer fixing unit
A stud bolt fixed to the inner wall of the hull on which the secondary heat insulating layer is installed;
A nut fastened to the stud bolt for securing the secondary heat insulating layer;
An elastic body that is fitted to the stud bolt and adjusts the elasticity according to the degree of deformation of the inner wall of the hull of the secondary heat insulating layer;
A compression fixing mold which is sandwiched between the stud bolts and laminated on the elastic body to prevent local damage of the secondary insulation layer; And
And a reference plate for height adjustment according to a degree of deformation of the inner wall of the hull of the secondary heat insulating layer.

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