KR102581644B1 - Insulation structure at corner of liquefied natural gas storage tank - Google Patents

Abstract

The corner insulation structure of a liquefied natural gas storage tank is disclosed. The liquefied natural gas storage tank according to the present invention includes a secondary insulation wall consisting of a plurality of secondary insulation panels arranged on the inner wall of the hull, a secondary sealing wall installed on the secondary insulation wall, and a secondary sealing wall on the secondary sealing wall. In a liquefied natural gas storage tank in which a primary insulation wall formed by arranging a plurality of primary insulation panels and a primary sealing wall installed on the primary insulation wall are sequentially stacked, a unit constituting the primary sealing wall As a member that closes the membrane, an end cap sheet in which multiple end cap-shaped wrinkles are formed on a flat metal sheet is used, thereby sealing the tank without bending corrugations at the corners of the storage tank. This comes true.

Description

Corner insulation structure of liquefied natural gas storage tank {INSULATION STRUCTURE AT CORNER OF LIQUEFIED NATURAL GAS STORAGE TANK}

The present invention relates to an insulation structure at the corner of a liquefied natural gas storage tank, and particularly to a connection structure at the corner of a metal membrane installed to seal the storage tank.

In general, natural gas is transported in gaseous form through onshore or offshore gas pipelines, or stored in LNG carriers as liquefied natural gas (Liquefied Natural Gas (LNG)) and transported to distant consumers.

LNG is obtained by cooling natural gas to a cryogenic temperature of approximately -163°C, and its volume is reduced to approximately 1/600 compared to natural gas in the gaseous state, making it very suitable for long-distance transportation by sea.

LNG can be loaded onto an LNG carrier, transported by sea, and unloaded at a destination on land, or loaded onto an LNG RV (Regasification Vessel) and transported by sea to a destination on land, then regasified and unloaded as natural gas. LNG transport ships and LNG RVs are equipped with storage tanks (also called 'cargo holds') that can withstand the extremely low temperatures of LNG.

LNG storage tanks can be classified into independent type and membrane type depending on whether the load of the cargo acts directly on the insulation material.

Membrane type storage tanks are divided into GTT NO 96 type and MARK Ⅲ type, and independent tank type storage tanks are divided into MOSS type and IHI-SPB type.

Membrane storage tanks include a secondary insulation wall installed on the inner wall of the hull, a secondary sealing wall installed on the secondary insulation wall, a primary insulation wall installed on the secondary sealing wall, and a primary insulation wall installed on the primary insulation wall. It has a structure in which the primary sealing walls are sequentially stacked.

The insulating wall is to prevent external heat from entering the storage tank to prevent LNG from vaporizing, and the sealing wall is to prevent LNG from leaking. In the case of membrane-type storage tanks, even if the primary sealing wall is damaged, It is composed of a double insulation structure to prevent leakage of LNG for a certain period of time by the car sealing wall.

Figure 1 is a diagram showing the corner part insulation structure of a conventional MARK III type storage tank, and Figure 2 is a side cross-sectional view of the corner part of a conventional MARK III type storage tank.

Referring to Figures 1 and 2, the conventional MARK III type storage tank has a primary sealing wall 40 made of a 1.2 mm thick stainless steel (SUS) membrane and a secondary sealing wall made of a triplex ( (not shown) and a primary insulation wall 30 and a secondary insulation wall 10 made of polyurethane foam, etc. are alternately stacked on the inner wall of the hull (H).

The primary seal wall 40 is formed with a plurality of wrinkles facing the inside of the tank to allow deformation of the membrane against heat shrinkage caused by the cryogenic LNG stored in the storage tank.

The corrugated primary sealing wall 40 is manufactured to an appropriate size and introduced into the storage tank, and the wrinkles formed between the adjacent primary sealing walls 40 are welded to each other throughout the storage tank.

Meanwhile, in the storage tank, chamfers are formed at an inclined angle on the upper and lower sides of the storage tank to reduce the sloshing impact of the cargo (LNG) stored inside, and each chamfer has a chamfer installed on the inclined surface of the chamfer. A corner member 50 that completes the sealed form of the storage tank by connecting the primary sealing wall 40 and the primary sealing wall 40 installed on the horizontal surface (floor, ceiling) or side of the storage tank. is installed.

The corner member 50 includes a corner piece 51 connecting the primary sealing walls 40 installed on each adjacent side of the storage tank, and a primary sealing wall connected to both ends of the corner pieces 51, respectively. An angle piece 52 that connects and seals the curved portions of the wrinkles formed in (40), and a wooden block 53 inserted at the height of the primary insulation wall 30 to support the corner piece 51. ) includes.

The corner piece 51 is provided in the form of a bent metal sheet extending along the edge of the corner portion of the storage tank. The corner piece 51 may be provided as a metal sheet bent at an angle formed by the chamfered slope of the storage tank and the horizontal (floor/ceiling) or side surfaces, for example, 135°.

The corner piece 51 is fixed to the corner of the storage tank by being mechanically fastened to the wooden block 53 located at the bottom using a rivet or screw.

At both ends of the corner piece 51, a primary sealing wall 40 installed on the inclined surface of the chamfer and a primary sealing wall 40 installed on the horizontal surface (floor/ceiling surface) or side of the storage tank are overlapped and welded, respectively. joined by

At this time, the angle piece 52 is installed to seal the open wrinkles formed in the primary sealing wall 40 connected to both ends of the corner piece 51. The angle piece 52 has wrinkles that are finished in an open form to correspond to the wrinkles formed on the primary sealing wall 40 so that the curved portions of the wrinkles on both sides can be connected to each other.

However, the wrinkles formed in the conventional angle piece 52 were manufactured by bending a single wrinkle at 135°, and the bent part where the wrinkles meet was bent sharply, so there was a risk of large concentration of stress, making it vulnerable to fatigue load. .

In addition, the conventional angle piece 52 is difficult to manufacture and process due to the geometric shape of the bend where wrinkles meet, and it is impossible to apply automatic welding in the field.

In addition, the conventional MARK III type storage tank including the corner member 50 as described above provides continuous flexibility as the wrinkles of the sealing walls formed on adjacent surfaces of the storage tank are connected to each other by the angle piece 52. Although there are advantages, stricter tolerance management is required to match the wrinkles on both sides, which hinders productivity in all processes, including welding work.

The corner member 50 applied to the conventional MARK III type storage tank is applied to the corner where the side and floor (or ceiling) of the storage tank form an angle of 135°, as shown in FIGS. 1 and 2. , The same applies to corners where the front or rear wall of the storage tank and the floor (or ceiling) form a 90° angle.

3 (a) and (b) show corner pieces (51, 51') and angle pieces (52, 52') installed at the 135° corner and 90° corner of the storage tank, respectively. When the conventional corner member 50 is applied to the corner of a storage tank forming a 90° angle, the corner piece 51' and the angle piece 52' are provided in a form bent at 90°.

Accordingly, the technical problem to be achieved by the present invention is to reduce the burden of tolerance by providing a structure that can facilitate the processing of the ends of the membrane constituting the primary sealing wall of the storage tank, and thus to manufacture the liquefied natural gas storage tank. The goal is to improve productivity.

In addition, the present invention aims to provide an insulation structure for the corner of a liquefied natural gas storage tank that alleviates the concentration of thermal stress in the corner of the storage tank, is advantageous in terms of fatigue life, and is capable of applying automatic welding in the field. Do this.

In order to achieve the above object, the present invention includes a secondary insulation wall consisting of a plurality of secondary insulation panels arranged on the inner wall of the hull, a secondary sealing wall installed on the secondary insulation wall, and the secondary insulation wall. In a liquefied natural gas storage tank in which a primary insulation wall consisting of a plurality of primary insulation panels arranged on the sealing wall and a primary sealing wall installed on the primary insulation wall are sequentially stacked, the storage tank a transverse connector installed to extend laterally along the edges of the front wall and the rear wall to support the first and second sealing walls; an Invar beam installed to extend longitudinally along a side edge of the storage tank and supporting the primary sealing wall; and a member that closes the unit membrane constituting the primary sealing wall, and includes an end cap sheet connecting the unit membrane and the transverse connector, or the unit membrane and the Invar beam, the end cap sheet is formed on the end cap sheet to correspond to a plurality of wrinkles formed in the unit membrane, one side is finished on the inside of the end cap sheet, and the other side is maintained in a wrinkled form. It includes a plurality of end cap wrinkles extending to the other end of the end cap sheet, wherein one end is welded to the transverse connector or the Invar beam and the other end is welded to the unit membrane. Provides corner insulation structure for gas storage tanks.

The unit membrane is made of a stainless steel (SUS) membrane sheet, and a plurality of wrinkles formed on the unit membrane in the transverse and longitudinal directions of the storage tank are formed continuously at regular intervals, and are attached to the end cap sheet. The distance between the end cap wrinkles formed may be the same as the distance between the wrinkles formed on the unit membrane.

The end cap sheet may be made of Invar material.

The end cap sheet may be provided in a flat shape with all three corners except for the other end where the end cap wrinkles extend.

The transverse connector and the Invar beam are made of Invar material and can be supported on the inner wall of the hull by an insulation box made of a plywood box.

The end cap sheet may further include auxiliary wrinkles extending long on the end cap sheet in a direction perpendicular to the end cap wrinkles.

In addition, in order to achieve the above object, the present invention includes a secondary insulation wall composed of a plurality of secondary insulation panels arranged on the inner wall of the hull, a secondary sealing wall installed on the secondary insulation wall, and the 2 In the liquefied natural gas storage tank in which a primary insulation wall consisting of a plurality of primary insulation panels arranged on the primary sealing wall and a primary sealing wall installed on the primary insulation wall are sequentially stacked, the primary As a member that closes the unit membrane constituting the sealing wall, an end cap sheet in which multiple end cap-shaped wrinkles are formed on a flat metal sheet is used, thereby preventing corrugation at the corners of the storage tank. Provides a corner insulation structure for a liquefied natural gas storage tank, characterized in that the tank is sealed without bending.

The corner insulation structure of the liquefied natural gas storage tank according to the present invention is installed to extend laterally along the edges of the front and rear walls of the storage tank, and includes a transverse supporting the primary and secondary sealing walls. connective body; and an Invar beam installed to extend longitudinally along a side edge of the storage tank to support the primary sealing wall, wherein the end cap sheet has one end connected to the transverse connector or the Invar beam. Welded, the other end may be welded to the unit membrane.

The unit membrane is made of stainless steel (SUS), the end cap sheet is made of Invar, the transverse connector and the Invar beam are made of Invar, and the plywood box It can be supported on the inner wall of the hull by an insulating box made of.

The liquefied natural gas storage tank according to the present invention has the effect of improving productivity by reducing tolerance burden as the end cap sheet including a plurality of end cap wrinkles facilitates processing of the ends of the primary sealing wall. According to the present invention, there is no need to mass-produce angle pieces, which were conventionally manufactured to connect wrinkles formed in the primary sealing wall, and the amount of welding can be reduced by more than four times.

In addition, in the present invention, as the end cap sheet is provided with a membrane plate made of Invar material, the concentration of thermal stress at the corner of the storage tank is alleviated, and the fatigue life is improved compared to the conventional angle piece including a bent wrinkle. It is advantageous in

In addition, in the present invention, since the end cap sheet is prepared as a membrane plate in which all parts except the wrinkles are flat, the size of the end cap sheet can be easily adjusted and the side cutting is possible, so the possibility of applying automatic welding is high. .

Figure 1 is a diagram showing the corner insulation structure of a conventional MARK III type storage tank.
Figure 2 is a side cross-sectional view of a corner portion of a conventional MARK III type storage tank.
Figure 3 is a diagram showing corner pieces and angle pieces installed at the corners of a conventional MARK III type storage tank, (a) being applied to the 135° corner of the storage tank, and (b) being applied to the 90° corner of the storage tank. It is applied to corners.
Figure 4 is a diagram showing the corner insulation structure of the liquefied natural gas storage tank according to the present invention.
Figure 5 is a view showing an end cap sheet installed at the corner of a liquefied natural gas storage tank according to the present invention.
Figure 6 is a view showing an end cap sheet including auxiliary wrinkles.

In order to fully understand the present invention, its operational advantages, and the objectives achieved by practicing the present invention, reference should be made to the accompanying drawings illustrating preferred embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, the present invention will be described in detail by explaining preferred embodiments of the present invention with reference to the attached drawings. The same reference numerals in each drawing indicate the same member.

In the present invention, the use of the terms 'primary' and 'secondary' refers to the function of primarily sealing or insulating LNG, or the function of secondary sealing or insulating, based on the LNG stored in the storage tank. It was used as a standard for classification.

Additionally, by convention, the terms 'top' or 'above' applied to elements of a tank refer to a direction towards the inside of the tank, regardless of the direction with respect to gravity, and likewise, the terms 'bottom' or 'below' refer to a direction towards the inside of the tank, regardless of the direction with respect to gravity. Regardless of the direction, it points towards the outside of the tank.

Figure 4 is a diagram showing the insulation structure of the corner part of the liquefied natural gas storage tank according to the present invention, Figure 5 is a diagram showing an end cap sheet installed at the corner part of the liquefied natural gas storage tank according to the present invention, and Figure 6 is a diagram showing an end cap sheet including auxiliary wrinkles.

Referring to Figure 4, the liquefied natural gas storage tank according to the present invention includes a secondary insulation wall 100 consisting of a plurality of secondary insulation panels arranged on the inner wall of the hull (H), and a secondary insulation wall 100. ) a secondary sealing wall 200 installed on the secondary sealing wall 200, a primary insulation wall 300 made of a plurality of primary insulation panels arranged on the secondary sealing wall 200, and a primary insulation wall 300 It includes a primary sealing wall 400 installed in.

The secondary insulation panel constituting the secondary insulation wall 100 is manufactured as a unit panel in the shape of a hexahedron, and a number of secondary insulation panels are arranged laterally and longitudinally on the inner wall of the hull (H) to form a secondary insulation wall. (100) can be formed.

The primary insulation panel constituting the primary insulation wall 300 is similarly manufactured as a hexahedral-shaped unit panel, and a plurality of primary insulation panels are arranged horizontally and longitudinally on the secondary sealing wall 200, resulting in 1 A car insulation wall 300 can be formed.

The primary and secondary insulation panels can be prepared as sandwich panels with plywood plywood glued to the top or bottom of polyurethane foam (PUF), or both, and have a width and length ratio of approximately 1:3. Branches can be manufactured as unit panels of the same size.

As described later, the primary and secondary insulation panels constituting the primary and secondary insulation walls 300 and 100 are composed of a flat invar membrane with a secondary sealing wall 200 having a flat shape. To this end, it is preferably made of reinforced polyurethane foam (Rigid Polyurethane Foam, RPUF), which has higher rigidity than general polyurethane foam.

The secondary insulation wall 100 may be fixed to the inner wall of the hull (H) with an adhesive such as epoxy mastic or studs, and the primary insulation wall 300 may be attached to the secondary insulation wall 100. With the secondary sealing wall 200 interposed between them, the primary insulation panel is coupled to a securing device provided on the top of the secondary insulation panel, thereby forming an upper portion of the secondary sealing wall 200. It can be tightly fixed to.

The secondary sealing wall 200 may be made of a flat Invar membrane.

The secondary sealing wall 200 is in close contact with the upper part of the secondary insulation wall 100 by welding a plurality of invar strakes to a tongue member installed on the upper part of the secondary insulation panel without any gaps. It can be installed properly. Invar strakes are strip-shaped metal plates with a narrow width.

The liquefied natural gas storage tank according to the present invention is a panel type in which the primary and secondary insulation walls (300, 100) are in the form of insulation panels in which wood plywood is bonded to the upper and/or lower surfaces of polyurethane foam. is provided, and the secondary sealing wall 200 is characterized in that it is composed of a flat Invar membrane in a flat shape.

Typically, flat Invar membranes have a low heat contraction coefficient, so they are not suitable for panel-type insulation systems where the insulation panels are made of polyurethane foam.

In order to apply a flat Invar membrane, like a conventional NO 96 type storage tank, the insulation wall supporting the membrane must be composed of an insulation box with low heat shrinkage deformation and high rigidity. An insulated box is a wooden box filled with perlite powder, etc., and has high compressive strength and rigidity.

However, in the present invention, by providing a structure to reinforce the rigidity of the secondary insulation wall 100, the secondary insulation wall 100 is provided with an insulation panel made of polyurethane foam, and the secondary sealing wall 200 is made of a flat invar membrane. Make it possible to configure it.

Specifically, the present invention further includes a transverse connector (510) installed at a corner of the storage tank to support both ends of the secondary sealing wall (200).

The transverse connector 510 is a grid-shaped structure installed along the edges of the front and rear walls of the storage tank, and supports both ends of the primary and secondary sealing walls 400 and 200 to protect against pressure applied to them. It serves to transmit various loads to the hull (H).

The transverse connector 510 is made of a highly rigid Invar material, is welded to an anchoring bar formed on the inner wall of the hull, and is fixedly installed at the corner of the storage tank. Both ends of the primary and secondary sealing walls (400, 200) are fixed and supported by welding on the transverse connector 510, thereby preventing various pressures applied to the primary and secondary sealing walls (400, 200). The load can be transferred to the hull (H) through the transverse connector.

Inside the transverse connector 510 and between the transverse connector 510 and the hull (H), a highly rigid insulating box (B, partially not shown) is interposed to support the transverse connector 510. It can be. The insulation box (B) may be provided in a plywood box filled with perlite powder.

In this way, according to the present invention, part of the load on the primary and secondary sealing walls 400 and 200 can be relieved by the transverse connector 510 installed at the corner of the storage tank, which is provided as a flat invar membrane. It is possible to construct the secondary insulation wall 100, which supports the lower part of the secondary sealing wall 200, from an insulation panel that is less rigid than the insulation box.

Therefore, in the present invention, when installing the secondary sealing wall 200 on the upper part of the secondary insulation wall 100, a welding line can be formed in a straight line, enabling automation of welding and thereby increasing productivity. There is an improving effect.

In addition, according to the present invention, the primary and secondary insulation walls (300, 100) are provided with insulation panels made of polyurethane foam, thereby improving insulation performance. The liquefied natural gas storage tank according to the present invention has a thickness of the primary insulation wall of approximately 40% or more and a thickness of the secondary insulation wall, compared to a conventional NO 96 type storage tank in which the insulation wall is provided in the form of an insulation box. It is possible to achieve the same insulation effect while reducing by approximately 20% or more.

The primary sealing wall 400 is sealed by direct contact with the LNG, and is preferably made of a stainless steel (SUS) membrane that has a better heat contraction coefficient than Invar. A plurality of wave-shaped wrinkles facing the inside of the storage tank may be formed on the primary sealing wall 400 to absorb shrinkage caused by cryogenic temperatures.

The primary sealing wall 400 is a primary insulation wall ( 300) can be installed in close contact with the upper part.

Hereinafter, with reference to FIGS. 4 to 6, the corner connection structure of the metal membrane forming the primary sealing wall in the liquefied natural gas storage tank according to the present invention will be described.

Prior to this, looking first at the support structure at the corner of the liquefied natural gas storage tank according to the present invention, the corner portion formed at a 90° angle along the edges of the front and rear walls of the storage tank has a An extending transverse connector 510 is installed to support both ends of the first and second sealing walls 400 and 200, respectively.

A trihedron 520 connecting two transverse connectors 510 is installed at the corner of the storage tank where the chamfered inclined surface of the storage tank meets the horizontal and vertical surfaces of the storage tank.

An invar beam 530 extending long in the longitudinal direction of the storage tank is installed at a corner formed at an angle of 135° between the chamfered inclined surface of the storage tank and the horizontal surface (floor/ceiling surface) or side surface. The invar beam 530 is a member that connects the trihedron 520 installed on the front wall of the storage tank and the trihedron (not shown) installed on the rear wall.

The trihedron 520 and the Invar beam 530 may be provided in a shape bent at 135° to correspond to the inclination of the chamfer. Both the trihedron 520 and the Invar beam 530 can be made of Invar material with a small heat contraction coefficient and high rigidity, and can be supported on the inner wall of the hull (H) by the insulation box (B). The insulation box (B) can be prepared by filling the inside of a plywood box with perlite powder to have high compressive strength and rigidity.

In summary, the liquefied natural gas storage tank according to the present invention has each side forming the storage tank to support the members (transverse structure, trihedron, or invar beam) installed along each corner of the storage tank. It has a structure in which highly rigid insulation boxes (B) are interposed along the edges, and an insulation panel made of polyurethane foam is interposed inside these.

Referring to FIG. 4, among the plurality of unit membranes 410 constituting the primary sealing wall 400, the unit membrane 410 disposed on the outermost side in the longitudinal direction of the storage tank includes the transverse structure 510 and It can be seen that the unit membrane 410, which is connected and disposed at the outermost part in the transverse direction of the storage tank, is connected to the Invar beam 530.

The unit membrane 410 has a structure in which a plurality of wrinkles are formed in the horizontal and vertical directions of the storage tank on a stainless steel (SUS) membrane sheet manufactured in an approximately rectangular shape. At this time, multiple transverse and longitudinal wrinkles are arranged continuously at regular intervals.

The present invention further includes an endcap sheet (600) as a member that closes the unit membrane (410) disposed at the corner of the storage tank in the primary sealing wall (400).

The end cap sheet 600 is a member that connects the unit membrane 410 disposed on the outermost side of the primary sealing wall 400 installed in the storage tank and the transverse structure 510 or invar beam 530, One end is welded to the transverse structure 510 or the Invar beam 530, and the other end is connected to the unit membrane 410 by overlap welding.

As shown in FIG. 5, the end cap sheet 600 may be provided with a plurality of end cap wrinkles 610 formed on a flat metal sheet.

The end cap wrinkles 610 may be provided in an end cap shape. That is, one side of the end cap wrinkle 610 is finished on the inside of the end cap sheet 600, and the other side extends to the other end of the end cap sheet 600 and can be finished in an open state to maintain the wrinkled shape. .

The end cap wrinkles 610 formed on the end cap sheet 600 are formed to correspond to the wrinkles of the unit membrane 410 that is adjacent to each other, and the end cap sheet 600 and the unit are formed in a state in which the corresponding wrinkles are engaged with each other. Welding between membranes 410 may be performed.

Accordingly, the end cap wrinkles 610 of the end cap sheet 600 may also be formed at regular intervals to correspond to the wrinkles formed at regular intervals in the unit membrane 410.

As shown in FIG. 4, in some cases, the end cap sheet 600 may be connected adjacently in the longitudinal direction of the unit membrane 410, or may be connected adjacently in the transverse direction of the unit membrane 410, so that the unit membrane 410 It is preferable that the spacing between the transverse wrinkles and the spacing between the longitudinal wrinkles formed at 410 are the same.

The end cap sheet 600 is preferably made of Invar material with a low coefficient of thermal expansion. Due to the nature of the material, Invar has material properties that are more than 7 times lower than stainless steel (SUS), so it can reduce thermal deformation and concentration of thermal stress.

In addition, even considering welding with the primary sealing wall 400 made of stainless steel (SUS), welding is performed between stainless steel (SUS) and Invar rather than between stainless steels (SUS). It's thermally better.

Meanwhile, as a preferred embodiment of the present invention, the unit membrane 410 constituting the primary sealing wall 400 has the same size as the plane of the primary and secondary insulation panels, that is, the horizontal and vertical ratio is approximately 1:3. It can be manufactured to have, and the horizontal width of the end cap sheet 600 can be manufactured to be the same as the horizontal width of the unit membrane 410. For example, when the unit membrane 410 is manufactured as a membrane sheet with a size of 1 m x 3 m, the horizontal width of the end cap sheet 600 may be manufactured to be 1 m.

According to this, in the corner portion formed at a 90° angle on the front or rear wall of the storage tank, the unit membrane 410 and the end cap sheet 600 are welded in one-to-one correspondence, and are formed at a 135° angle on the side of the storage tank. In the corner portion (chamfer portion), three end cap sheets 600 may be welded to one unit membrane 410.

As shown in FIG. 6, the end cap sheet 600 according to the present invention may further include auxiliary wrinkles 620 extending long along the width direction of the sheet.

The auxiliary wrinkles 620 absorb heat contraction in a direction perpendicular to the direction of heat contraction absorbed by the end cap wrinkles 610, and can more effectively alleviate thermal stress concentrated in the corners of the storage tank.

In addition, in the present invention, the transverse connector 510 or the invar beam 530 to which one end of the end cap sheet 600 is connected is supported by the insulation box (B), while the other end of the end cap sheet 600 is supported by the insulation box (B). Since the connected primary sealing wall 400 is supported by an insulation panel made of polyurethane, a difference in height may occur between the insulation box (B) and the insulation panel due to the difference in heat shrinkage, and the auxiliary wrinkles 620 are like this. It also serves to flexibly respond to the height difference between the insulation box (B) and the insulation panel, thereby relieving thermal stress from being concentrated in the area where the height difference occurs.

The end cap sheet 600 according to the present invention can be viewed as a flat membrane plate with end cap wrinkles 610 formed, so side cutting is possible, which reduces tolerance burden and improves field application efficiency. .

That is, because the end cap sheet 600 has all three corners flat except for the other end where the end cap wrinkles 610 extend, the size of the edges can be easily adjusted and can be cut and applied on site according to the installation tolerance. It is possible.

In addition, in the conventional MARK Ⅲ type storage tank, different types of angle pieces had to be manufactured in large quantities to apply to the 90° corner and the 135° corner, whereas in the liquefied natural gas storage tank according to the present invention, the 90° and 135° corners were used. °The finishing of the membrane placed at the corner can be done with the same member (end cap sheet), and as a result, the amount of welding can be reduced by more than 4 times, which can greatly improve productivity in the production of storage tanks.

The present invention is not limited to the described embodiments, and it is obvious to those skilled in the art that various modifications and changes can be made without departing from the spirit and scope of the present invention. Accordingly, such modifications or variations should be considered to fall within the scope of the claims of the present invention.

100: Secondary insulation wall
200: secondary sealing wall
300: Primary insulation wall
400: Primary sealing wall 410: Unit membrane
510: Transverse connector 520: Trihedron
530: Invar beam
600: End cap sheet 610: End cap wrinkles
620: Auxiliary wrinkles

Claims (9)

A secondary insulation wall consisting of a plurality of secondary insulation panels arranged on the inner wall of the hull, a secondary sealing wall installed on the secondary insulation wall, and a plurality of primary insulation panels arranged on the secondary sealing wall. In a liquefied natural gas storage tank in which a primary insulation wall consisting of a primary insulation wall and a primary sealing wall installed on the primary insulation wall are sequentially stacked,
a transverse connector installed to extend laterally along the edges of the front and rear walls of the storage tank and supporting the first and second sealing walls;
an Invar beam installed to extend longitudinally along a side edge of the storage tank and supporting the primary sealing wall; and
A member that closes the unit membrane constituting the primary sealing wall, and includes an end cap sheet connecting the unit membrane and the transverse connector or the unit membrane and the Invar beam,
The end cap sheet is,
It is formed on the end cap sheet to correspond to a plurality of wrinkles formed in the unit membrane, one side of which is finished on the inside of the end cap sheet, and the other side is formed at the other end of the end cap sheet while maintaining the wrinkled form. A plurality of end cap creases extending to; and
It includes auxiliary wrinkles extending long on the end cap sheet in a direction perpendicular to the end cap wrinkles,
As both ends of the auxiliary pleats are finished on the inside of the end cap sheet, all three corners of the end cap sheet except the other end where the end cap pleats extend are flat.
The end cap sheet is characterized in that one end is welded to the transverse connector or the Invar beam, and the other end is welded to the unit membrane.
Corner insulation structure of a liquefied natural gas storage tank. In claim 1,
The unit membrane is made of a stainless steel (SUS) membrane sheet,
A plurality of wrinkles formed on the unit membrane in the transverse and longitudinal directions of the storage tank are formed continuously at regular intervals,
Characterized in that the spacing between the end cap wrinkles formed on the end cap sheet is the same as the spacing between wrinkles formed on the unit membrane.
Corner insulation structure of a liquefied natural gas storage tank. In claim 2,
The end cap sheet is characterized in that it is made of Invar material,
Corner insulation structure of a liquefied natural gas storage tank. delete In claim 3,
The transverse connector and the Invar beam are made of Invar material,
Characterized in that it is supported on the inner wall of the hull by an insulating box made of plywood box,
Corner insulation structure of a liquefied natural gas storage tank. delete delete delete delete

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