A sealed film and sealed can for storing and transporting liquefied gas

Abstract

The application relates to a sealed film and sealed tank for storing and transporting liquefied gas, the sealed film comprising a planar area, a first corrugation and a second corrugation, the first corrugation and the second corrugation having a similar M-shaped cross section, the first corrugation and the second corrugation being perpendicularly intersected to form a corrugation node; a top of the corrugation node forms a smooth W-shaped outer contour along an extension direction of the first corrugation, the first corrugation extends to the corrugation node and is smoothly connected with the W-shaped outer contour of the corrugation node; the second corrugation extends to a position below the W-shaped outer contour of the corrugation node and is connected with a side surface of the corrugation node, the side surface of the corrugation node connected with the second corrugation forms a smooth M-shaped side surface, and the sealed film is used for sealing in the sealed tank. The sealed film of the application is provided with the corrugation with the special cross section shape and the corrugation node, when the sealed tank is loaded and unloaded, under the conditions of low-temperature warming and rapid freezing, the first corrugation and the second corrugation reduce thermal expansion and contraction of the planar area, and damage of the sealed film is avoided.

Description

Technical Field

[0001] This invention relates to the field of cryogenic insulated storage tanks, and more specifically to a sealing membrane and a sealing tank for storing and transporting liquefied gas. Background Technology

[0002] Liquefied natural gas (LNG) is typically transported and stored in sealed tanks. LNG temperatures generally range from -163°C to -80°C, while liquefied petroleum gas (LPG) temperatures range from -50°C to 0°C. These tanks are usually fitted with a sealing membrane that adheres to the inner wall of the tank and is in direct contact with the liquefied gas. When these tanks are installed on chemical tankers, marine structures, or other floating structures, the liquefied gas inside can slosh due to sea conditions or wind. This causes fluctuations in the free surface of the liquid, resulting in nonlinear, random movements of the liquid within the tank. These fluctuations often impact the tank, and when the impact stress reaches a significant level, it can damage the sealing membrane or tank wall, causing the membrane to lose its function and ultimately leading to a liquefied gas leak.

[0003] Therefore, avoiding liquefied gas leakage is the key to the construction technology of liquid tanks in cryogenic liquid transport vessels such as LNG carriers and LPG carriers. In order to avoid damage to the membrane or tank of the sealed tank, it is of paramount importance to ensure that the sealing membrane inside the sealed tank has sufficient temperature shrinkage margin and can withstand large shaking impact pressure.

[0004] Prior art, such as the invention patent application with publication number CN116658798A, discloses a sealing layer and storage device having a central ridge section, having a second horizontal corrugation, a first horizontal corrugation and a junction of the two corrugations, the junction having a ridge section that spans the second horizontal corrugation, the dimension in the second horizontal direction at the middle position of the ridge section being smaller than the dimension in the first horizontal direction at the top of the second horizontal corrugation and smaller than the dimension in the second horizontal direction at the top of the first horizontal corrugation, and the height of the ridge section being greater than the height of the first horizontal corrugation.

[0005] Another existing technology is the Mark III enclosure system from the French company GTT. The Mark III uses 304L stainless steel as the material and has a unique raised part that forms a metal corrugated plate. The 304L stainless steel is corrugated in a pleated form ("Application of 304L Corrugated Plate in LNG Membrane Tanks", Jiang Xiaobo, Wei Ming, Xing Le, Du Yu, Chen Nianlai, Hu Chengjie, China Petroleum and Chemical Standards, No. 13, July 11, 2023). Summary of the Invention

[0006] To improve the impact resistance of the sealing membrane inside the sealed container and increase the temperature shrinkage allowance, this invention provides a sealing membrane and sealed container for storing and transporting liquefied gas. The technical objective of this invention is achieved through the following technical solution:

[0007] A sealing membrane for storing and transporting liquefied natural gas includes a planar region and a first corrugation and a second corrugation protruding from the planar region. The first corrugation is uniformly and parallelly distributed along the planar region, and the second corrugation is uniformly and parallelly distributed along a direction perpendicular to the first corrugation within the planar region. The first and second corrugations have an M-shaped cross-section, and a corrugated joint is formed at the position where the first and second corrugations intersect perpendicularly. The top of the corrugated joint forms a smooth W-shaped outer contour along the extension direction of the first corrugation. The first corrugation extends to the corrugated joint and smoothly connects with the W-shaped outer contour of the corrugated joint. The second corrugation extends to a position below the W-shaped outer contour of the corrugated joint and connects with the side of the corrugated joint. The side of the corrugated joint connecting with the side of the second corrugation forms a smooth M-shaped side.

[0008] Furthermore, the height of the first ripple is higher than the height of the second ripple, and the width of the first ripple is greater than the width of the second ripple.

[0009] Furthermore, the height ratio of the second ripple to the height of the first ripple is between 0.5 and 0.8.

[0010] Furthermore, the first and second corrugations have the same M-shaped cross-section shape, both including a central arc segment formed in the middle of the M-shaped cross-section, side arc segments symmetrically distributed on both sides of the central arc segment, and connecting arc segments symmetrically distributed along the central arc segment and connecting the planar areas; transition arc segments connect the central arc segment and the side arc segments, as well as the side arc segments and the connecting arc segments; the central arc segment is concave, and the side arc segments are convex relative to the central arc segment to form a higher position.

[0011] Further, the transition arc includes a first transition arc segment, a second transition arc segment, and a third transition arc segment. The first transition arc segment connects the middle arc segment and the side arc segment. The side arc segment, the second transition arc segment, the third transition arc segment, and the connecting arc segment are connected sequentially. The radius of the middle arc segment is R1, the radius of the side arc segment is R2, the radius of the connecting arc segment is R3, the radius of the first transition arc segment is R4, the radius of the second transition arc segment is R5, and the radius of the third transition arc segment is R6. The height distance H between the elevated area formed by the side arc segment and the planar region is denoted by H, in mm. R1, R2, R3, R4, R5, R6, and H satisfy the following:

[0012] 4≤H: R1≤8;

[0013] 2.5≤R1:R2≤4;

[0014] 1.3≤R1:R3≤2;

[0015] 8≤R4:R2≤15;

[0016] 6≤R5:R2≤10;

[0017] R5≤R4;

[0018] 4≤R6:H≤8.

[0019] Furthermore, the height H of the first and second corrugations ranges from 32 to 86 mm.

[0020] Furthermore, the W-shaped outer contour of the corrugated section includes a centrally convex arc-shaped top surface and symmetrically arranged side arc-shaped top surfaces on both sides of the central arc-shaped top surface and concave relative to the central arc-shaped top surface. A sixth transition arc surface smoothly connects the side arc-shaped top surfaces and the central arc-shaped top surface. The side arc-shaped top surfaces are smoothly connected to the first corrugation through a seventh transition arc surface. The radius of the arc surface of the central arc-shaped top surface is equal to 1.5 times the radius of the central arc segment R1 of the first corrugation. The radius of the arc surface of the side arc-shaped top surface is equal to 1.5 times the radius of the side arc segment R2 of the first corrugation. The radius of the arc surface of the sixth transition arc surface is equal to 1.5 times the radius of the first transition arc segment R4 of the first corrugation. The radius of the arc surface of the seventh transition arc surface is equal to 1.5 times the radius of the second transition arc surface R5 of the first corrugation. The span between the two sides of the seventh transition arc surface where it intersects with the first corrugation is equal to 1.5 times the width of the first corrugation.

[0021] Furthermore, the M-shaped side of the corrugated joint includes a central arc surface that convex outwards and side arc surfaces that are symmetrically arranged inwards from the central arc surface. A fourth transition arc surface connects the central arc surface and the side arc surfaces, and a fifth transition arc surface connects the side arc surfaces and the first corrugation.

[0022] Furthermore, the distance between the fifth transition arc surfaces on both sides of the central arc surface and the connection position of the first corrugation is B; the radius of the central arc surface is R7; the radius of the side arc surface is R8; the radius of the fourth transition arc surface is R9; the radius of the fifth transition arc surface is R10; and the concave depth of the side arc surface is h (in mm). The following relationships are satisfied between R7, R8, R9, R10, B, and h:

[0023] B: h=30;

[0024] 0.8≤R7:R8≤1.25;

[0025] R9: B≥1;

[0026] R10:B≥1.5.

[0027] Furthermore, B is equal to 1.2 times the width of the first ripple.

[0028] Furthermore, support members are respectively filled below the first and second corrugations.

[0029] Furthermore, the support includes a support frame that extends along the extension directions of the first corrugation and the second corrugation and has endpoints at the locations of the corrugation nodes.

[0030] Furthermore, the support also includes a hollow channel disposed inside the support frame, the hollow channel extending along the extension direction of the support frame and having an end point at the location of the corrugated section.

[0031] Furthermore, the area between the interior of the support structure and the exterior of the hollow channel is also filled with support filler.

[0032] Furthermore, the support filler is glass fiber or low-temperature adhesive.

[0033] Furthermore, the thickness of the support frame is 5-10mm, and the support frame is made of plywood, polyethylene, or fiberglass.

[0034] Furthermore, a triangular inclined plane is set between the first corrugation, the planar region, and the M-shaped side of the corrugation section. The three sides of the inclined plane are smoothly connected to the first corrugation, the planar region, and the M-shaped side of the corrugation section, respectively. The included angle between the inclined plane and the planar region is 30-45°.

[0035] The present invention also provides a sealed container for storing and transporting liquefied natural gas, wherein the aforementioned sealing membrane is provided inside the sealed container.

[0036] Furthermore, the sealed container is also equipped with an insulation layer, which includes a main insulation layer and a secondary insulation layer. The sealing film, the main insulation layer, the sealing film, the secondary insulation layer, and the sealed container body are arranged in sequence.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] 1. The present invention provides a sealing membrane. The sealing membrane has a special cross-sectional shape and corrugated joints. When the sealed container is loaded and unloaded, the first and second corrugations reduce the thermal expansion and contraction of the planar area under the conditions of low temperature warming and rapid freezing. The stress generated by displacement is also borne by the corrugations and folds. The corrugations indirectly provide a large displacement margin.

[0039] 2. The sealing membrane of the present invention, through the setting of first and second corrugations of different heights and widths, and through the M-shaped pleat elasticity and the staggered arrangement of different heights, evenly bears the shaking impact load, effectively avoiding damage to the sealing membrane and the sealed container.

[0040] 3. The present invention also provides a sealed container in which the sealing film of the present application is installed inside the sealed container to improve the performance of the sealed container against shaking impact loads. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of a sealed membrane structure for storing and transporting liquefied gas according to the present invention.

[0042] Figure 2 This is an enlarged view of the corrugated section location of the sealing film in this invention.

[0043] Figure 3 This is a schematic diagram of an M-shaped cross-section of the first or second corrugation of the sealing film in this invention.

[0044] Figure 4 This is a schematic diagram of the W-shaped outer contour of the corrugated section of the sealing film in this invention.

[0045] Figure 5 This is a top view of the corrugated region of the sealing film in this invention.

[0046] Figure 6 This is a schematic diagram of the M-shaped side profile of the sealing film in this invention.

[0047] Figure 7 This is a schematic diagram of the support structure for the sealing membrane in this invention.

[0048] Figure 8 This is a schematic diagram of the sealed tank structure for storing and transporting liquefied natural gas according to the present invention.

[0049] Figure 9 This is a simulation graph of the plastic strain of the sealing film of the present invention.

[0050] Figure 10 It is a simulation spectrum of plastic strain of the sealing membrane in the existing technology.

[0051] Figure 11 This is a simulation diagram of the sealing membrane deformation under pressure according to the present invention.

[0052] Figure 12 It is a simulation diagram of the deformation of the sealing membrane under pressure in the existing technology.

[0053] In the diagram, 1. Planar area; 2. First corrugation; 3. Second corrugation; 4. Corrugation joint; 5. W-shaped outer contour; 6. M-shaped side surface; 7. Central arc top surface; 8. Side arc top surface; 9. Sixth transition arc surface; 10. Seventh transition arc surface; 11. Sloping surface; 12. Support frame; 13. Hollow channel; 14. Filler; 15. Insulation layer; 16. Receiving groove. Detailed Implementation

[0054] The technical solution of the present invention will be further described below with reference to specific embodiments:

[0055] A sealing membrane for storing and transporting liquefied natural gas, such as Figure 1As shown, the structure includes a planar region 1, and a first corrugation 2 and a second corrugation 3 protruding from the planar region 1. The first corrugation 2 is uniformly and parallelly distributed along the planar region, and the second corrugation 3 is uniformly and parallelly distributed within the planar region 1 along a direction perpendicular to the first corrugation 2. The first corrugation 2 and the second corrugation 3 have an M-shaped cross-section. A corrugation node 4 is formed at the position where the first corrugation 2 and the second corrugation 3 intersect perpendicularly. The top of the corrugation node 4 forms a smooth W-shaped outer contour 5 along the extension direction of the first corrugation 2. The first corrugation 2 extends to the corrugation node 4 and smoothly connects with the W-shaped outer contour 5 of the corrugation node 4. The second corrugation 3 extends to the position below the W-shaped outer contour 5 of the corrugation node 4 and connects with the side of the corrugation node 4. The corrugation node 4 connects with the side of the second corrugation 3 to form a smooth M-shaped side 6, as shown. Figure 2 As shown.

[0056] The first and second corrugations have the same M-shaped cross-section shape, both including a central arc segment formed in the middle of the M-shaped cross-section, side arc segments symmetrically distributed on both sides of the central arc segment, and connecting arc segments symmetrically distributed along the central arc segment and connecting the planar areas; transition arc segments connect the central arc segment and the side arc segments, as well as the side arc segments and the connecting arc segments; the central arc segment is concave, and the side arc segments are convex relative to the central arc segment, forming a higher position. Specifically, as shown... Figure 3 As shown, the transition arc includes a first transition arc segment, a second transition arc segment, and a third transition arc segment. The first transition arc segment connects the middle arc segment and the side arc segment. The side arc segment, the second transition arc segment, the third transition arc segment, and the connecting arc segment are connected sequentially. The first transition arc segment and the middle arc segment are externally tangent, the side arc segment and the first transition arc segment are internally tangent, the side arc segment and the second transition arc segment are internally tangent, the second transition arc segment and the third transition arc segment are internally tangent, and the third transition arc segment and the connecting arc segment are externally tangent. The radius of the middle arc segment is R1. The radius of the side arc segment is R2, the radius of the connecting arc segment is R3, the radius of the first transition arc segment is R4, the radius of the second transition arc segment is R5, the radius of the third transition arc segment is R6, the height distance between the high position formed by the side arc segment and the plane area is H, the height H of the first and second corrugations ranges from 32 to 86 mm, the width of the first corrugation 2 and the width of the second corrugation 3 are the distance D between the positions of the connecting arc segments and the plane area, in mm; R1, R2, R3, R4, R5, R6 and H satisfy:

[0057] 4≤H: R1≤8;

[0058] 2.5≤R1:R2≤4;

[0059] 1.3≤R1:R3≤2;

[0060] 8≤R4:R2≤15;

[0061] 6≤R5:R2≤10;

[0062] R5≤R4;

[0063] 4≤R6:H≤8.

[0064] Preferably, the height of the first corrugation 2 is higher than the height of the second corrugation 3, and the width of the first corrugation 2 is greater than the width of the second corrugation 3. The combination of M-shaped corrugations of different heights, through the elasticity of the M-shaped corrugations and the staggered design with varying heights, evenly distributes the swaying impact load, effectively preventing damage to the sealing membrane. Preferably, the ratio of the height of the second corrugation to the height of the first corrugation is 0.5-0.8. In this embodiment, the height of the first corrugation is 85mm, the radius of the middle arc segment of the first corrugation is R1=16mm, the radius of the side arc segment of the first corrugation is R2=5.5mm, the radius of the connecting arc segment of the first corrugation is R3=10.6mm, the radius of the first transition arc segment of the first corrugation is R4=47mm, the radius of the second transition arc segment of the first corrugation is R5=33mm, and the radius of the third transition arc segment of the first corrugation is R6=350mm. Correspondingly, when the height of the first corrugation is 85mm, the height range of the second corrugation is 42.5-68mm according to the height ratio range of 0.5-0.8.

[0065] In this embodiment, the R1, R2, R3, R4, R5, R6, and H of the second corrugation are each 0.6 times that of the first corrugation. That is, the second corrugation has R1=9.6mm, R2=3.3mm, R3=6.36mm, R4=28.2mm, R5=19.8mm, R6=210mm, and H=51mm.

[0066] The W-shaped outer contour of the corrugated joint is as follows Figure 4As shown, it includes a central arc-shaped top surface 7 with a central protrusion, and side arc-shaped top surfaces 8 symmetrically arranged on both sides of the central arc-shaped top surface 7 and recessed relative to the central arc-shaped top surface 7. A sixth transition arc surface 9 is smoothly connected between the side arc-shaped top surfaces 8 and the central arc-shaped top surface 7. The side arc-shaped top surfaces 8 are smoothly connected to the first corrugation 2 through a seventh transition arc surface 10. The central arc-shaped top surface 7 and the sixth transition arc surface 9 are internally tangent, the sixth transition arc surface 9 and the side arc-shaped top surface 8 are externally tangent, and the side arc-shaped top surface 8 and the seventh transition arc surface are internally tangent. The radius of the arc surface 7 of the middle arc is 1.5 times the radius of the middle arc segment R1 of the first corrugation, which is 24mm; the radius of the arc surface 8 of the side arc is 1.5 times the radius of the side arc segment R2 of the first corrugation, which is 8.25mm; the radius of the arc surface 9 of the sixth transition arc is 1.5 times the radius of the first transition arc segment R4 of the first corrugation, which is 70.5mm; the radius of the arc surface 10 of the seventh transition arc is 1.5 times the radius of the second transition arc surface R5 of the first corrugation, which is 49.5mm; and the span between the two sides of the seventh transition arc surface 10 where it intersects with the first corrugation 2 is 1.5 times the width of the first corrugation.

[0067] The M-shaped side of the corrugated joint, as shown Figure 5 and Figure 6 As shown in Figure 5, which is a top view of one of the corrugated section regions, from... Figure 5 As can be seen, the corrugated joints form symmetrical M-shaped side surfaces, and the lines of these M-shaped side surfaces are as follows: Figure 6 As shown, the structure includes a central convex arc surface and symmetrically arranged side arc surfaces recessed within the central arc surface. A fourth transition arc surface connects the central arc surface and the side arc surfaces, and a fifth transition arc surface connects the side arc surfaces and the first corrugation. The central arc surface and the fourth transition arc surface are externally tangent, the fourth transition arc surface and the side arc surfaces are internally tangent, and the side arc surfaces and the fifth transition arc surface are internally tangent. The radius of the central arc surface is R7, the radius of the side arc surfaces is R8, the radius of the fourth transition arc surface is R9, and the radius of the fifth transition arc surface is R10. The distance between the fifth transition arc surfaces on both sides of the central arc surface and the connection points with the first corrugation is B, where B is equal to 1.2 times the width of the first corrugation. The concave depth of the side arc surfaces is h (in mm). R7, R8, R9, R10, B, and h satisfy the following relationship:

[0068] B: h=30;

[0069] 0.8≤R7:R8≤1.25;

[0070] R9: B≥1;

[0071] R10:B≥1.5.

[0072] In this embodiment: h=5.46mm, B=164mm, R7=15.4mm, R8=14.83mm, R9=166.3mm, R10=252.6mm.

[0073] Preferably, the area between the first corrugation 2, the planar region 1, and the M-shaped side surface 6 of the corrugation node is configured as a triangular inclined surface 11, such as... Figure 5 As shown, the three sides of the inclined plane 11 are smoothly connected to the first corrugation 2, the planar region and the M-shaped side 6 of the corrugation section 1, respectively, and the included angle between the inclined plane 11 and the planar region 1 is 30-45°.

[0074] Preferably, support members are filled below the first and second corrugations respectively, and the support members support the first and second corrugations, thereby further enhancing the strength of the sealing film.

[0075] In one embodiment, the support member includes a support frame 12 that conforms to the inner walls of the first and second corrugations, such as... Figure 7 As shown, the support frame 12 extends along the extension direction of the first corrugation and the second corrugation and has endpoints at the corrugation joints. The support member is only supported below the first corrugation and the second corrugation, and no support is provided in the corrugation joint area.

[0076] To facilitate cable insertion and air circulation, the support also includes a hollow channel 13 disposed inside the support frame 12. The hollow channel 13 extends along the extension direction of the support frame 12 and has its endpoints at the corrugated joints. In this embodiment, the hollow channel 13 has the same extension length as the support frame 12 and its ends are flush. The thickness of the support frame 12 is 5-10mm, and the support frame is made of plywood, polyethylene, or fiberglass.

[0077] Preferably, the area between the interior of the support frame 12 and the exterior of the hollow channel 13 is further filled with a support filler 14. The filler 14 provides support and reinforcement to the support frame 12. The filler 14 may be made of materials such as glass fiber or low-temperature adhesive. Glass fiber has a certain rigidity and hardness, which can provide strong support and reinforcement. The low-temperature adhesive is a low-temperature resistant adhesive. While providing some support and reinforcement, the low-temperature adhesive itself has high flexibility, which can maintain a certain displacement margin and also prevent damage to the support structure.

[0078] The sealing membrane of this invention is formed by welding metal plates using a sealing welding method. Specifically, stainless steel or high-manganese steel plates with a thickness between 2-5 mm and a yield strength between 170 MPa and 500 MPa are selected. The membrane is divided into several units with corrugated sections according to their locations. Each unit is individually processed with a first corrugation, a second corrugation, and a corrugated section. These units are then spliced ​​and welded together to form a corrugated mold. The first corrugation, the second corrugation, and the corrugated section are formed by extrusion.

[0079] This embodiment also provides a sealed container for storing and transporting liquefied natural gas, such as... Figure 8 As shown, a sealing membrane as described in the above embodiment is disposed inside the sealed container. Preferably, the sealed container contains two insulating layers 15 and two sealing membranes as described in the above embodiment. The two insulating layers serve as the main insulating layer and the secondary insulating layer, respectively, and the two sealing membranes serve as the main sealing membrane and the secondary sealing membrane, respectively. When installed inside the sealed container, they are stacked in the order of secondary insulating layer, sealing membrane, main insulating layer, and sealing membrane. Preferably, the main insulating layer has a receiving groove 16 corresponding to the first and second corrugations of the sealing membrane of the secondary insulating layer. The support below the first and second corrugations supports the insulating layer 15. Figure 7 As shown.

[0080] To better illustrate the characteristics of the sealing membrane of the present invention, the plastic strain performance and compressive deformation resistance of the sealing membrane under thermal expansion and contraction were simulated and tested. In this embodiment, the test was performed using Ansys software for simulation analysis.

[0081] 1. Under low temperature warming and rapid freezing conditions, the first and second corrugations of the sealing film of the present invention reduce the thermal expansion and contraction of the planar area, and the stress generated by displacement is also borne by the pleated form of the corrugations, which indirectly provide a large displacement margin.

[0082] For the case of loading liquefied natural gas, i.e., when the temperature drops from room temperature (20°C) to -163°C, the plastic strain of the sealing membrane of the present invention is as follows: Figure 9 As shown, the maximum value is 5.1786 mm / m; Figure 10 The plastic strain of the sealing membrane in the prior art under the same conditions is 6.2515 mm / m, which is about 21% higher than the plastic strain value in this invention. Under the same conditions, the smaller the plastic strain, the better.

[0083] 2. The sealing membrane of the present invention has an M-shaped cross section due to the presence of the first and second corrugations, which enables it to evenly bear the swaying impact load, effectively avoiding damage to the sealing membrane and the sealed container.

[0084] The swaying impact load manifests as a uniform pressure applied to the surface of the sealing membrane. Under the same applied pressure of 270 kPa, the compressive deformation of the sealing membrane is as follows: Figure 11 As shown, the maximum deformation value of the sealing film of the present invention is 0.2012 mm. Figure 12 The deformation value of the metal corrugated plate of the Mark III type enclosure system in the prior art under the same conditions is 0.36582 mm. Under the same conditions, the deformation value of the sealing film of the present invention is significantly smaller, which can effectively withstand the shaking impact load and avoid damage to the sealing tank.

[0085] This embodiment is merely a further explanation of the present invention and is not intended to limit the present invention. Those skilled in the art can make non-inventive modifications to this embodiment as needed after reading this specification, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A sealing membrane for storing and transporting liquefied natural gas, characterized in that, The corrugated sheet comprises a planar area, a first corrugation and a second corrugation protruding from the planar area, the first corrugation is uniformly and parallelly distributed along the planar area, the second corrugation is uniformly and parallelly distributed along a direction perpendicular to the first corrugation, the first corrugation and the second corrugation have a similar M-shaped cross section, and a corrugation node is formed at a position where the first corrugation and the second corrugation intersect perpendicularly; a top of the corrugation node forms a smooth W-shaped outer profile along an extension direction of the first corrugation, the first corrugation extends to the corrugation node and is smoothly connected with the W-shaped outer profile of the corrugation node; the second corrugation extends to a position below the W-shaped outer profile of the corrugation node and is connected with a side surface of the corrugation node, and the side surface of the corrugation node connected with the second corrugation forms a smooth M-shaped side surface.

2. A sealed membrane for storing and transporting liquefied natural gas according to claim 1, characterized in that, The height of the first corrugation is higher than the height of the second corrugation, and the width of the first corrugation is greater than the width of the second corrugation.

3. A sealing membrane for storing and transporting liquefied natural gas according to claim 2, characterized in that, The height ratio of the second corrugation to the first corrugation is 0.5-0.

8.

4. A containment membrane for storing and transporting liquefied natural gas according to claim 2, wherein, The M-shaped cross sections of the first corrugation and the second corrugation have the same shape, each comprising a middle circular arc segment formed in the middle of the M-shaped cross section, side edge circular arc segments symmetrically distributed on both sides of the middle circular arc segment, and a connecting circular arc segment symmetrically distributed along the middle circular arc segment and connected with the planar area; a transition circular arc segment is connected between the middle circular arc segment and the side edge circular arc segment and between the side edge circular arc segment and the connecting circular arc segment; the middle circular arc segment is concave downward, and the side edge circular arc segment is convex upward relative to the middle circular arc segment to form a high position.

5. A containment membrane for storing and transporting liquefied natural gas according to claim 4, wherein, The transition circular arc comprises a first transition circular arc segment, a second transition circular arc segment and a third transition circular arc segment, the first transition circular arc segment is connected between the middle circular arc segment and the side edge circular arc segment, and the side edge circular arc segment, the second transition circular arc segment, the third transition circular arc segment and the connecting circular arc segment are sequentially connected; the radius of the middle circular arc segment is R1, the radius of the side edge circular arc segment is R2, the radius of the connecting circular arc segment is R3, the radius of the first transition circular arc segment is R4, the radius of the second transition circular arc segment is R5, the radius of the third transition circular arc segment is R6, and the height distance of the high position formed by the side edge circular arc segment from the planar area is H, in mm; R1, R2, R3, R4, R5, R6 and H satisfy: 4≤H:R1≤8; 2.5≤R1:R2≤4; 1.3≤R1:R3≤2; 8≤R4:R2≤15; 6≤R5:R2≤10; R5≤R4; 4≤R6: H≤8.

6. A containment membrane for storing and transporting liquefied natural gas according to claim 5, wherein, The height H of the first corrugation and the second corrugation ranges from 32 mm to 86 mm.

7. A containment membrane for storing and transporting liquefied natural gas according to claim 6, wherein, The W-shaped outer profile of the corrugated section comprises a middle convex middle circular arc top surface, symmetrically arranged side surface circular arc top surfaces on both sides of the middle circular arc top surface and concave relative to the middle circular arc top surface, and a sixth transition circular arc surface smoothly connecting between the side surface circular arc top surface and the middle circular arc top surface, and the side surface circular arc top surface is smoothly connected with the first corrugation through a seventh transition circular arc surface, the arc surface radius of the middle circular arc top surface is equal to 1.5 times of the middle circular arc segment R1 of the first corrugation, the arc surface radius of the side surface circular arc top surface is equal to 1.5 times of the side surface circular arc segment R2 of the first corrugation, the arc surface radius of the sixth transition circular arc surface is equal to 1.5 times of the first transition circular arc segment R4 of the first corrugation, the arc surface radius of the seventh transition circular arc surface is equal to 1.5 times of the second transition circular arc surface R5 of the first corrugation, and the span between the positions where the seventh transition circular arc surface meets the first corrugation on both sides is equal to 1.5 times of the width of the first corrugation.

8. A sealing membrane for storing and transporting liquefied natural gas according to claim 7, characterized in that, The M-shaped side surface of the corrugated section comprises a middle convex middle circular arc surface and symmetrically arranged side surface circular arc surfaces concave in the middle circular arc surface, and a fourth transition circular arc surface is connected between the middle circular arc surface and the side surface circular arc surface, and a fifth transition circular arc surface is connected between the side surface circular arc surface and the first corrugation.

9. A containment membrane for storing and transporting liquefied natural gas according to claim 8, wherein, The distance between the fifth transition circular arc surface on both sides of the middle circular arc surface and the position where the first corrugation is connected is B, the radius of the middle circular arc surface is R7, the radius of the side surface circular arc surface is R8, the radius of the fourth transition circular arc surface is R9, the radius of the fifth transition circular arc surface is R10, and the concave depth of the side surface circular arc surface is h, unit: mm; R7, R8, R9, R10, B, h satisfy the following relationship: B:h=30; 0.8≤R7:R8≤1.25; R9:B≥1; R10:B≥1.

5.

10. A containment membrane for storing and transporting liquefied natural gas according to claim 9, wherein, The B is equal to 1.2 times of the width of the first corrugation.

11. A containment membrane for storing and transporting liquefied natural gas according to claim 1, wherein, The first corrugation and the second corrugation are respectively filled with a support.

12. A containment membrane for storing and transporting liquefied natural gas according to claim 11, wherein, The support comprises a support frame, which extends along the extension direction of the first corrugation and the second corrugation and sets an end point at the position of the corrugated section.

13. A containment membrane for storing and transporting liquefied natural gas according to claim 12, wherein, The support further comprises a hollow channel arranged inside the support frame, which extends along the extension direction of the support frame and sets an end point at the position of the corrugated section.

14. A containment membrane for storing and transporting liquefied natural gas according to claim 13, wherein, The area between the inside of the support frame and the outside of the hollow channel is also filled with a support filler.

15. A containment membrane for storing and transporting liquefied natural gas according to claim 14, wherein, The support filler is glass fiber or low-temperature glue.

16. The sealed membrane for storing and transporting liquefied natural gas of claim 12, wherein, The thickness of the support frame is 5-10 mm, and the support frame is selected from plywood, polyethylene or glass fiber.

17. The sealed membrane for storing and transporting liquefied natural gas of claim 1, wherein, The first corrugation, the planar area and the M-shaped side surface of the corrugated section are arranged as a triangular inclined surface, and the three sides of the inclined surface are smoothly connected with the first corrugation, the planar area and the M-shaped side surface of the corrugated section, respectively, and the included angle between the inclined surface and the planar area is 30-45°.

18. A sealed tank for storing and transporting liquefied natural gas, characterized in that, A sealing film is arranged in the inside of the sealed tank, and the sealing film is as claimed in any one of claims 1-17.

19. A sealed tank for storing and transporting liquefied natural gas according to claim 18, wherein, An insulation layer is further arranged in the inside of the sealed tank, and the insulation layer comprises a main layer insulation layer and a secondary layer insulation layer, and the sealing film, the main layer insulation layer, the sealing film, the secondary layer insulation layer and the tank body of the sealed tank are sequentially arranged.

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