KR101964638B1 - Onshore membrane tank including embedded plate - Google Patents

Abstract

Disclosed is an onshore membrane tank which is installed on shore for storing liquefied gas and uses concrete to construct a tank body (3). The onshore membrane tank includes: an insulation floor (4) and an insulation wall (5) installed in the tank body; and a first barrier (10) and a second barrier (20) laminated and installed in the insulation floor and the insulation wall for receiving liquefied gas in a cryogenic state in a sealed state. The first barrier is installed to surround the floor of the tank body and the inner surface of a cylindrical wall, and the second barrier can be installed over a part of the floor of the tank body and the cylindrical wall. An edge of an upper end of the second barrier can be connected to an embedded plate (30) installed in the tank body.

Description

TECHNICAL FIELD [0001] The present invention relates to an ONSHORE MEMBRANE TANK INCLUDING EMBEDDED PLATE,

Field of the Invention [0002] The present invention relates to a land membrane tank for storing liquefied gas, and more particularly, to a land membrane tank having a landfill plate installed in concrete to fix a membrane constituting a secondary barrier.

Typically, land-based liquefied gas storage tanks are used to store liquefied gas for liquefied natural gas (LNG), liquefied petroleum gas (LPG) and other liquefied gases, various liquefied gases such as liquefied oxygen, liquefied nitrogen, And has a cylindrical shape whose roof is dome-shaped.

Conventional land liquefied gas storage tanks are made by casting concrete on a foundation to form a cylindrical tank body having a substantially dome-shaped lid.

According to the conventional land liquefied gas storage tank, a heat insulating layer is provided inside a tank body (i.e., outer tank) made of concrete, and an inner tank that directly receives liquefied gas is installed in the heat insulating layer.

The inner tank is a portion directly contacting the liquefied gas at a cryogenic temperature. Therefore, the inner tank can be made of a material such as low-temperature steel that can withstand cryogenic temperatures. A waterproof layer can be provided between the insulating layer and the tank body to prevent moisture penetration.

The conventional land-type liquefied gas storage tank constructed as described above prevents leakage of liquefied gas by forming inner tanks with primary and secondary walls made of membranes.

The membrane constituting the primary and secondary barriers is made of a cryogenic steel material which is relatively expensive in order to stably accommodate the liquefied gas in a cryogenic temperature state and is made of a specific material It has a wrinkle part.

For this reason, membranes are expensive materials and ways to reduce the use of membranes to reduce the production cost of land-based membrane tanks for storing liquefied gases can be considered.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a buried plate capable of reducing a membrane used in a secondary barrier by constructing a secondary barrier between a primary barrier and a secondary barrier, The present invention provides a membrane tank for land use.

According to an aspect of the present invention, there is provided a land-use membrane tank installed on a land to store liquefied gas and constructed with a concrete body by using concrete, And a primary barrier and a secondary barrier laminated inside the heat insulating floor and the heat insulating wall to receive the liquefied gas in a cryogenic state in a sealed state, Wherein the secondary barrier is installed over the bottom of the tank body and a part of the cylindrical wall, and the upper edge of the secondary barrier is disposed on the bottom of the tank body, A land membrane tank having a landfill plate may be provided.

The secondary barrier may be installed over at least a portion of the entire height of the tank body.

The embedding type plate may be provided on the inner circumferential surface of the tank body so as to have a ring shape.

The embedding plate may have one or more anchor members extending into the interior of the tank body to be fixedly mounted to the tank body.

In order for the upper edge of the secondary barrier to be connected to the buried plate, the upper edge of the secondary barrier may extend through the insulating wall to the inner surface of the tank body.

The upper membrane disposed at the upper edge of the secondary barrier may have a curved shape.

The upper membrane may include a first bend portion that curves toward the outside in the horizontal direction toward the upper side and a second bend portion that bends upwardly beyond the horizontal inflection point.

A straight line may be formed between the first bend portion and the second bend portion. The curvatures of the first bend portion and the second bend portion may be the same or different from each other.

The top membrane may comprise a top wrinkle membrane, a top planar membrane, and a top connecting membrane.

The upper membrane may be arranged in a sequential and repeatable fashion, including a top wrinkle membrane, an upper planar membrane, an upper connecting membrane, and a top planar membrane.

The top corrugated membrane can be extended and bonded to a higher position on the embedding plate compared to the top first flat membrane, the top second flat membrane, and the top connecting membrane.

According to the present invention, it is possible to provide a land membrane tank capable of saving a membrane used in a secondary barrier by installing a secondary barrier among the primary and secondary walls over a lower portion of the tank.

According to the present invention, there can also be provided a land-use membrane tank in which a buried plate is installed on the outer tank of the tank so as to close the membrane of the secondary barrier installed over a lower part of the tank.

Accordingly, the membrane tank for land use according to the present invention can reduce the amount of the membrane, which is a relatively expensive material, thereby reducing the material cost and reducing the cost due to shortening of the air required for installing the membrane.

1 is a schematic partial cross-sectional view of a land membrane tank according to the present invention.
2 is a schematic cross-sectional view of a schematic main part of a land membrane tank according to the present invention for explaining a state where a membrane is attached to a buried plate;
3 is a view showing a state in which a secondary barrier is attached to a buried plate inside the tank.
Fig. 4 is a view showing a top corrugated membrane in which a corrugated portion of a plurality of unit membranes constituting a secondary barrier attached to a buried plate is formed, wherein (a) is a front view and (b) is a right side view.
FIG. 5 is a view showing an upper first planar membrane having a corrugated portion among a plurality of unit membranes constituting a secondary barrier attached to a buried plate, wherein FIG. 5 (a) is a front view and FIG. 5 (b) is a right sectional view.
FIG. 6 is a top plan view showing an upper second planar membrane having a corrugated portion among a plurality of unit membranes constituting a secondary barrier attached to a buried plate. FIG. 6 (a) is a front view and FIG. 6 (b) is a right sectional view.
Fig. 7 is a view showing a top connecting membrane having a corrugated portion among a plurality of unit membranes constituting a secondary barrier attached to a buried plate, wherein (a) is a front view and (b) is a right-hand sectional view.
FIG. 8 is a schematic partial perspective view showing a part of a land membrane tank according to the present invention taken in order to explain a state where a membrane is attached to a buried plate. FIG.

Hereinafter, a membrane tank for land use according to a preferred embodiment of the present invention will be described in detail with reference to the drawings.

In the following description, the terms "interior" or "interior" shall be taken to mean the interior of the storage tank and the terms "exterior" or "exterior" shall be taken to mean outside the storage tank.

FIG. 1 is a schematic partial cross-sectional view of a membrane tank for land use according to the present invention, and FIG. 2 is a schematic view of a schematic main part of a membrane tank according to the present invention for explaining a state where a membrane is attached to a landfill plate. Sectional view is shown.

As shown in Fig. 1, the surface membrane tank is formed by forming a cylindrical tank body 3 having a substantially dome-shaped lid by pouring concrete on the foundation 1. [

In the interior of the tank body 3 made of concrete, there are provided an insulating floor 4 and a heat insulating wall 5, and between the insulating wall 5 and the tank body 3, for example, epoxy The waterproof layer 2 may be provided. On the other hand, a primary wall 10 and a secondary wall 20 capable of accommodating liquefied gas in a cryogenic temperature state in a laminated state are installed in the heat insulating floor 4 and the heat insulating wall 5.

The primary barrier 10 is a portion directly contacting the liquefied gas and the secondary barrier 20 is disposed outside the primary barrier 10 to prevent leakage of the liquefied gas to the outside of the tank when the primary barrier is broken Secondarily prevent. The primary barrier 10 and the secondary barrier 20 are formed by welding a plurality of membranes by welding and a method of attaching a plurality of membranes to each other to form primary and secondary barriers is a general membrane- And therefore, detailed description thereof will be omitted.

Membranes constituting the primary barrier 10 and the secondary barrier 20 can be made of a cryogenic steel material capable of withstanding cryogenic temperatures.

In this embodiment, a spacer for maintaining a gap may be provided between the primary barrier 10 and the secondary barrier 20, and this spacer may be made of, for example, a plywood material.

As shown in Fig. 1, the primary barrier 10 is installed so as to surround the entirety of the tank except the ceiling of the tank, that is, the bottom of the tank and the inner surface of the cylindrical wall. According to the present invention, the secondary barrier 20 is the same as the primary barrier 10 in that it is installed on the entire inner surface in the case of the bottom of the tank, but in the case of the cylindrical wall, And is different from the car barrier 10.

The height at which the secondary barrier is installed may be, for example, about 5 m. In the case of the land membrane tank according to the present invention, when the primary barrier 10 is damaged and the liquefied gas leaks, the leaked liquefied gas flows down toward the bottom of the tank, and at the bottom of the tank, It becomes high between the barriers. Since the liquefied gas collected between the primary wall and the secondary wall is gradually evaporated, if the nitrogen is circulated to the heat insulating wall, it is possible to detect the leakage of the liquefied gas while simultaneously supplying the vaporized gas to the outside of the tank Can be discharged.

Therefore, even if the secondary barrier is not installed to the height of the entire tank, the liquefied gas is not leaked to the outside of the tank until the primary barrier is maintained by detecting leakage of the liquefied gas due to damage of the primary barrier .

As shown in FIGS. 1 and 2, an inner side of the tank body 3 is provided with an embedded plate 30 to which the upper edge of the secondary barrier 20 can be connected. The embedding plate 30 is installed at a specific height with respect to the inner circumferential surface of the tank body 3 made of concrete.

Since the tank body 3 is substantially cylindrical, a plurality of the embedding plates 30 provided along the inner circumferential surface of the tank body can be formed into a ring shape as a whole. In detail, one embedding plate 30 can have an approximately elongated rectangular plate shape, and a plurality of embedding plates 30 can be continuously arranged on the inner surface of the tank body 3, Ring shape. As used herein, the expression "a plurality of embedding plates as a whole is ring-shaped" is a concept including not only a circular shape but a circular shape other than a circular shape.

As shown in Figure 2, each embedding plate 30 extends into the interior of the tank body 3, i. E., To be fixedly mounted to the concrete forming the outer tank of the tank One or more anchor members 32 may be provided. The anchor member 32 can strengthen the adhesion between the embedded plate 30 and the concrete laid thereon. Although only three anchor members 32 are shown in Fig. 2, the number and location of the anchor members 32 can be changed as needed.

The upper edge of the secondary barrier 20 may be connected to the buried plate 30, for example by welding. For this purpose, the embedding plate 30 can be made of a metal material capable of welding.

As shown in Fig. 1, at the bottom of the tank, the secondary barrier 20 is arranged close to the primary barrier 10, which is installed inside the tank relative to the secondary barrier, The corrugations of the corrugation and the secondary barrier are formed at the same position. In order to maintain the gap between the primary barrier and the secondary barrier at the bottom of the tank, a spacer made, for example, of plywood can be interposed between the primary barrier and the secondary barrier. That is, the primary barrier and the secondary barrier may be spaced apart from each other by a distance corresponding to the thickness of the spacer.

However, in order for the upper edge of the secondary barrier to be connected to the buried plate 30, the upper edge of the secondary barrier must extend through the heat insulating wall 5 to the inner surface of the tank body 3.

To this end, the membrane disposed at the upper edge of the secondary barrier (hereinafter referred to as the upper membrane 40) may have a curved shape as shown in FIGS. 2 and 3. In particular, referring to FIG. 2, the upper membrane 40 has a curved shape (first bend portion) toward the outside in the horizontal direction as it goes upward, and then a curved shape (second bend portion) .

A straight line may be formed between the first bend section 40a and the second bend section 40b. The curvatures of the first bend section 40a and the second bend section 40b may be constant or may be different. When the curvatures of the first bend section 40a and the second bend section 40b are different, the radius of curvature of the second bend section 40b may be smaller than the radius of curvature of the first bend section 40a. In addition, the first bend section 40a and the second bend section 40b may be formed with the same curvature over the entire section, or may be formed by continuing sections formed with different curvatures.

The upper membrane, specifically, the first and second bends 40a, 40b, 40c, 40d, 40d, 40d, 40d, 40d, Heat insulating members 5a and 5b made of, for example, plywood or polyurethane foam (PUF) may be provided on the upper and lower portions of the portions where the heat insulating members 40a and 40b are formed. These heat insulating members 5a and 5b can be prefabricated to have shapes corresponding to the shapes of the first and second curved portions 40a and 40b of the upper membrane.

3 is a view showing a state in which the secondary barrier is attached to the buried plate from the inside of the tank.

As shown in FIG. 3, the top membrane 40 may be composed of a plurality of membrane pieces having a plurality of shapes. For example, the top membrane 40 can be classified according to its shape to include an upper wrinkle membrane 42, an upper first planar membrane 44, an upper second planar membrane 45, and an upper connecting membrane 46, . ≪ / RTI > 3, the top membrane 40 includes a top corrugated membrane 42, an upper first flat membrane 44, an upper connecting membrane 46, and an upper second flat membrane 45 ) May be repeatedly arranged in order.

FIG. 4 shows a top corrugated membrane having a corrugated portion of a plurality of membranes constituting a secondary barrier attached to a buried plate. FIG. 4 (a) is a front view of the top corrugated membrane, and FIG. 4 ) Is a side view of the upper wrinkle membrane.

4, the upper corrugated membrane 42 has a plurality of corrugations 42c formed to extend along the longitudinal direction of the upper corrugated membrane 42, as shown in FIG.

Referring again to FIG. 3, the upper wrinkle membrane 42 is installed to extend along the vertical direction of the tank as a whole, and accordingly, the wrinkle portion 42c also extends along the vertical direction of the tank as a whole.

Further, the upper corrugated membrane 42 is welded so as to be disposed approximately at the center of the embedding plate 30. The upper corrugated membrane 42 may extend upwards on the embedding plate 30 relative to the upper first planar membrane 44, the upper second planar membrane 45 and the upper connecting membrane 46.

As shown in Fig. 4 (b), the upper wrinkle membrane 42 curves toward the outer side in the horizontal direction (first bending portion) toward the upper side and then curves upward again Curved portion).

A straight line may be formed between the first bend section 42a and the second bend section 42b. The curvature of the first bend section 42a and the second bend section 42b may be constant or may be different. When the curvature of the first bend section 42a and the second bend section 42b are different, the radius of curvature of the second bend section 42b may be smaller than the radius of curvature of the first bend section 42a. In addition, the first bend section 42a and the second bend section 42b may be formed with the same curvature over the entire section, or may be formed by continuing sections formed by different curvatures.

5 shows an upper first planar membrane having a corrugated portion of a plurality of unit membranes constituting a secondary barrier attached to a buried plate. FIG. 5 (a) is a front view of the upper first planar membrane, 5 (b) is a cross-sectional view taken along line AA shown in (a).

3 and 5 (a), an upper first planar membrane 44 is disposed between the upper corrugated membrane 42 and the upper connecting membrane 46 and bonded to the embedded plate 30. The upper first flat membrane 44 has a protruding portion 44c which is formed by protruding upward at an edge of the upper flat membrane 44 facing the upper corrugated membrane 42 (left in FIG. 5 (a)) when viewed from the front. The protrusion 44c has a concave arcuate edge 44e for smooth connection with the upper edge 44d of the upper first flat membrane. The projections 44c and the arcuate edges 44e are formed at the portions where the upper corrugated membrane 42 and the upper first flat membrane 44 are connected to each other so that concentration of stress on the connecting portions can be avoided .

3, the height of the protruding portion 44c is greater than the height of the upper corrugated membrane 42 in a state where the upper first flat membrane 44 and the upper corrugated membrane 42 are bonded to the embedding plate 30, Can be set lower.

As shown in FIG. 5 (b), the upper first flat membrane 44 is curved toward the outer side in the horizontal direction (first bending portion) toward the upper side, and then passes the horizontal inflection point And again has a shape curved upward (second bend portion).

The first bending portion 44a and the second bending portion 44b of the upper first flat membrane 44 have the same shape as the first bending portion 42a and the second bending portion 42b of the upper wrinkle membrane 42 Respectively.

In the case of the upper first flat membrane 44 as well as the upper corrugated membrane 42, a straight line may be formed between the first curved portion 44a and the second curved portion 44b. The curvatures of the first bend section 44a and the second bend section 44b may be constant or may be different. When the first bend section 44a and the second bend section 44b have different curvatures, the radius of curvature of the second bend section 44b may be smaller than the radius of curvature of the first bend section 44a. In addition, the first bend section 42a and the second bend section 42b may be formed with the same curvature over the entire section, or may be formed by continuing sections formed by different curvatures.

6 shows an upper second planar membrane having a corrugated portion of a plurality of unit membranes constituting a secondary barrier attached to a buried plate. FIG. 6 (a) is a front view of the upper second planar membrane, 6 (b) is a cross-sectional view taken along the line BB shown in (a).

Referring to Figures 3 and 6A, an upper second planar membrane 45 is disposed between the upper corrugated membrane 42 and the upper connecting membrane 46 and bonded to the buried plate 30. The upper second flat membrane 45 has a protrusion 45c formed by protruding upward at an edge of the upper flat membrane 45 that is in contact with the upper corrugated membrane 42 as viewed from the front (right side in FIG. 6 (a)). The protrusion 45c has a concave arcuate edge 45e for smooth connection with the upper edge 45d of the upper second flat membrane. The projections 45c and the arc-shaped edges 45e are formed at the portions where the upper corrugated membrane 42 and the upper second flat membrane 45 are connected to each other, so that concentration of stress on the connection portions can be avoided .

The upper first planar membrane 44 may have a shape symmetrical to the left and right as compared to the upper second planar membrane 45. That is, in each front view, the upper first planar membrane 44 has a protrusion 44c at the upper left, while the upper second planar membrane 45 has a protrusion 45c at the upper right.

3, the height of the protruding portion 45c in the state where the upper second flat membrane 45 and the upper corrugated membrane 42 are bonded to the embedding type plate 30 is equal to the height of the upper corrugated membrane 42 Can be set lower.

As shown in Fig. 6 (b), from the side view, the upper second flat membrane 45 is curved toward the outside in the horizontal direction (first bending portion) toward the upper side and then passes through the horizontal inflection point And again has a shape curved upward (second bend portion).

The first bend section 45a and the second bend section 45b of the upper second planar membrane 45 have the same shape as the first bend section 42a and the second bend section 42b of the upper wrinkle membrane 42 Respectively.

In the case of the upper second flat membrane 45 as well as the upper corrugated membrane 42, a linear portion may be formed between the first bent portion 45a and the second bent portion 45b. The curvatures of the first bend section 45a and the second bend section 45b may be constant or may be different. When the curvatures of the first bend section 45a and the second bend section 45b are different, the radius of curvature of the second bend section 45b may be smaller than the radius of curvature of the first bend section 45a. In addition, the first bend section 45a and the second bend section 45b may be formed with the same curvature over the entire section, or may be formed by continuing sections formed with different curvatures.

7 shows a top connecting membrane having a corrugated portion among a plurality of unit membranes constituting a secondary barrier attached to a buried plate. FIG. 7 (a) is a front view of the top connecting membrane, and FIG. 7 b) is a cross-sectional view taken along the CC line shown in (a).

3 and 7 (a), a top connecting membrane 46 is disposed between the top first planar membrane 44 and the top second planar membrane 45 and bonded to the buried plate 30 .

The upper membranes 40 are not only extended in the vertical direction of the tank but are curved so as to extend from the inside to the outside of the tank (see FIG. 1). Since the tank is generally cylindrical in shape, The respective membrane pieces constituting the upper membrane in the inside of the tank are overlapped with each other. To prevent this, as shown in Figure 7 (a), the top connecting membrane 46 may have a generally trapezoidal shape.

3, in a state where the upper connecting membrane 46 is bonded to the embedding plate 30, the height of the upper connecting membrane 46 is higher than that of the upper first flat membrane 44 and the upper connecting membrane 46, 2 plane membrane 45. The height of the two-

As shown in Fig. 7 (b), the upper connecting membrane 46 is curved toward the outside in the horizontal direction (first bending portion) toward the upper side as viewed from the side, (Second bending portion).

The first curved portion 46a and the second curved portion 46b of the upper connecting membrane 46 are formed so as to have a shape similar to the first curved portion 42a and the second curved portion 42b of the upper corrugated membrane 42 .

In the case of the upper connecting membrane 46, a straight portion may be formed between the first bending portion 46a and the second bending portion 46b, like the upper wrinkle membrane 42. The curvatures of the first bend section 46a and the second bend section 46b may be constant or may be different. The curvature radius of the second curve portion 46b may be smaller than the curvature radius of the first curve portion 46a when the curvatures of the first curve portion 46a and the second curve portion 46b are different from each other. In addition, the first curve portion 46a and the second curve portion 46b may be formed with the same curvature over the entire section, or may be formed by continuing the sections formed by different curvatures.

FIG. 8 is a schematic partial perspective view showing a portion of a membrane tank for land use according to the present invention, in order to explain a state where a membrane is attached to a buried plate.

8, only a portion of the upper first planar membrane 44 and the upper second planar membrane 45 are shown, so that protrusions 44c, 45c formed in each membrane are not shown in FIG.

The land tank is generally cylindrical in shape, but the tank body can be constructed by a unit concrete block in the shape of a rectangular parallelepiped for convenience in actual construction. Each of the embedding plates 30 provided along the inner circumferential surface of the tank body may have a substantially long rectangular plate shape as described above and a plurality of embedding plates 30 may be provided on the inner surface of the tank body 3 And is continuously arranged on the inner surface to form a polygonal ring shape of a tetragonal shape.

As a result, two adjoining buried plates 30 are disposed on the inner surface of the tank body 3 at an angle A, The upper connecting membrane 46 is joined to the portion where the two embedding plates 30 make the angle A.

3, the upper part of the upper wrinkle membrane 42 is joined to the central part of the embedding plate 30, and the upper part of the upper wrinkle membrane 42, which is joined to the embedding plate 30, (42c) is extended. The upper portion of the upper wrinkle membrane 42 extends over a predetermined length on the embedding plate 30 so that the wrinkle portion 42c can be formed at the overlapping portion with the embedding plate 30. [

3, the top corrugated membrane 42 is placed at the highest level in the center of each buried plate 30 and the top connecting membrane 46 is positioned over the two buried plates 30, The upper first planar membrane 44 and the upper second planar membrane 45 are disposed between the upper corrugated membrane 42 and the upper connecting membrane 46, Which is advantageous in terms of absorption of stress due to thermal deformation of the secondary barrier 20 which may occur upon storage of the gas.

When all of the joining portions of the upper membrane to the embedding plate 30 have the same height, when the stress due to thermal deformation is generated, the upper connecting membrane 30, which is disposed at a portion where the embedding plates 30 are connected to each other at an angle, The stress can be concentrated on the surface. Thereby undesirably deteriorating the bonding state between the upper connecting membrane 46 and the plate-type plate 30.

Although the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Therefore, the scope of the present invention should not be limited to the embodiments described, but should be determined by the equivalents of the claims, as well as the claims that follow.

1: Foundation
3: Tank body
5: Insulation wall
10: Primary barrier
20: Secondary barrier
30: Recessed plate
42: Upper wrinkle membrane
44: upper first flat membrane
45: Upper second planar membrane
46: Upper connecting membrane

Claims (12)

As a land-use membrane tank installed on the land to store liquefied gas and constructing a tank body by using concrete,
An insulating floor and an insulating wall provided inside the tank body,
A primary barrier and a secondary barrier laminated inside the heat insulating floor and the heat insulating wall to accommodate the liquefied gas in a cryogenic state in a sealed state,
/ RTI >
Wherein the primary barrier is installed to surround the bottom of the tank body and the inner surface of the cylindrical wall and the secondary barrier is provided over the bottom of the tank body and a portion of the cylindrical wall,
Wherein an upper edge of the secondary barrier is connected to an embedded plate provided in the tank body,
In order for the upper edge of the secondary barrier to be connected to the buried plate, the upper edge of the secondary barrier extends through the insulating wall to the inner surface of the tank body,
The upper membrane disposed at the upper edge of the secondary barrier has a curved shape,
Wherein the upper membrane comprises a first curved portion curved toward the outside in the horizontal direction toward the upper side and a second curved portion curved upward again beyond the horizontal inflection point. The method according to claim 1,
Wherein the secondary barrier is provided over at least a portion of the entire height of the tank body. The method according to claim 1,
Wherein the embedding type plate is provided so as to have a ring shape on an inner peripheral surface of the tank body. The method according to claim 1,
The landfill plate having at least one anchor member extending into the interior of the tank body for fixedly mounting to the tank body. delete delete delete The method according to claim 1,
And a straight portion is formed between the first bend portion and the second bend portion. The method according to claim 1,
Wherein a curvature of the first bend section and a bend section of the second bend section are different from each other. The method according to claim 1,
Wherein the top membrane comprises a top wrinkle membrane, an upper first flat membrane, an upper second flat membrane, and a top connecting membrane. The method of claim 10,
Wherein the top membrane has an embedding plate having an upper wrinkle membrane, an upper first planar membrane, an upper connecting membrane, and an upper second planar membrane, which are sequentially and repeatedly arranged. The method of claim 10,
Wherein the upper wrinkle membrane is extended and bonded to a higher position on the embedding plate relative to the upper first flat membrane, the upper second flat membrane, and the upper connecting membrane.

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