Corrugated plate and liquefied gas storage vessel equipped with same

Abstract

The present invention provides a corrugated plate and a liquefied gas storage container comprising the corrugated plate. [Solution] The corrugated plate includes a plate body, orthogonal first and second corrugations, and a crossing structure formed at the crossing position. The first corrugations are higher than the second corrugations. The crossing structure includes a peak, a rib, and a recess. The peak is located at the center of the crossing position and has a protruding height greater than that of the first corrugations. A rib extending from the peak toward the plate body is formed in each of the four quadrants formed by the crossing of the corrugations, and its overall extension direction crosses the first corrugations, the second corrugations, and the height direction, respectively. The plate includes four recesses, each located in one quadrant, formed on the outer surface of the first corrugations, and sandwiched between the first crest of the first corrugations and the rib.

Description

[Technical Field]

[0001] The present invention relates to the field of marine engineering installations, in particular liquefied gas storage vessels for marine installations such as ships, and in particular to a corrugated plate and a transport installation, in particular a liquefied gas storage vessel for marine installations such as ships, comprising said corrugated plate. The storage vessel is in particular a liquefied gas storage tank for marine installations such as ships, and the liquefied gas may be, for example, liquefied natural gas, liquid nitrogen, liquid oxygen, liquid hydrogen, or liquid helium. [Background technology]

[0002] Due to its green, environmentally friendly and highly efficient advantages, liquefied natural gas (LNG) has always been positioned as the energy of choice to replace oil, and it has become one of the fastest-growing energy industries in the world. As China's economy grows rapidly and environmental regulations become stricter, the application and development of LNG is becoming increasingly important to businesses, especially in situations where smog is common, and this has led to a rapid increase in society's demand for clean energy. LNG is one of the key directions for China's future clean energy development. LNG is usually transported by marine facilities such as ships. The main components of an LNG receiving terminal are unloading at the wharf, LNG storage, processing, and overseas transportation. Among these, LNG tanks, which play a role in storage, are always managed as the critical path of the entire project, as they require the longest construction period, the most advanced technology, and the most difficult aspects of construction. Furthermore, the structural design and technological innovation of LNG tanks are attracting attention from both domestic and international industry peers. In LNG tanks, the corrugated plates forming the sealing layer must be able to maintain good sealing properties and stability under various conditions of use, so the structure and quality of the corrugated plates are particularly important, and the requirements for the manufacturing process of the corrugated plates are also increasing. In conventional corrugated plates, there is room for improvement in the uniformity, smoothness, and strength of the material at the corrugations, especially at the intersections of the vertical and horizontal corrugations. Therefore, there is a need to provide a corrugated sheet and a storage container comprising the corrugated sheet to at least partially solve the above problems. Summary of the Invention

[0003] To at least partially achieve the above object, the present invention provides a corrugated plate for a liquefied gas storage container, the corrugated plate comprising a plate body, first corrugations, and second corrugations, wherein the first corrugations protrude at a first height relative to the plate body along a height direction perpendicular to the plate body and extend in a first direction parallel to the plate body, the second corrugations protrude at a second height relative to the plate body along the height direction and extend in a second direction parallel to the plate body, the first height is greater than the second height, the maximum width of the first corrugations in the direction perpendicular to the first direction is greater than the maximum width of the second corrugations in the direction perpendicular to the second direction, the first corrugations and the second corrugations intersect at right angles to form an intersection structure at an intersection position, the intersection structure including a peak, a rib, and a recess; the apex is located at the center of the intersection position, and the height of the apex protruding from the plate body along the height direction is greater than the first height, There are four ribs, and each rib is located in one of four quadrants formed by the first crest of the first wave portion and the second crest of the second wave portion intersecting at right angles, and extends from the top toward the plate body, and the overall extension direction of the rib intersects with the first direction, the second direction, and the height direction, respectively; There are four recesses, each of which is located in one of the four quadrants, is formed on the outer surface of the first wave portion, is sandwiched between the first crest of the first wave portion and the rib, and is recessed inward relative to the outer surface of the first wave portion. In some embodiments, the rib terminates at an outer surface of the first corrugation. In some embodiments, the rib smoothly connects and transitions with the outer surface of the first corrugation. In some embodiments, the recess has a recess edge, the recess edge being defined by a transition portion from an outwardly convex or flat to an inwardly concave portion on the outer surface of the first corrugation, the recess edge smoothly connecting and transitioning with the rib. In some embodiments, the recessed edge extends from the rib to the first crest of the first corrugation, and the recess is bounded by the rib, the recessed edge and the first crest of the first corrugation. In some embodiments, in a plane perpendicular to the height direction, the projection of the recess edge is an outwardly protruding curve, the included angle of the projection of the rib with respect to the first direction is greater than the included angle of the tangent of the projection of the recess edge with respect to the first direction, and the length of the projection of the rib in the first direction is less than the length of the projection of the recess edge in the first direction. In some embodiments, the angle formed by a tangent to a projection of the recess edge on a plane perpendicular to the height direction and the first direction gradually increases. In some embodiments, the recess depth relative to the outer surface of the first corrugation gradually increases along a direction from the edge of the recess towards the centre of the recess. In some embodiments, when observed along the height direction, the ribs and the recesses are symmetrical with respect to a first crest of the first corrugation and / or a second crest of the second corrugation. In some embodiments, the height of the first crest at the position where the recess is formed in the first wave portion is the same as the height of the first crest at other positions in the first wave portion. In some embodiments, a groove is formed between two ribs located on the same side of the first corrugation, the groove being located above the second corrugation, and the groove bottom extends perpendicular to the plate body. Another aspect of the present invention provides a storage container for liquefied gas, wherein the wall of the storage container includes a base layer and a sealing layer positioned inside the base layer, and the sealing layer includes the corrugated plate described in any one of the preceding claims. According to the technical object of the present invention, when the second corrugated portion is formed, the crossing structure can make the upper and lower surfaces at the crossing position of the corrugated plate have uniform line lengths, thereby realizing uniform thickness, avoiding excessive thickening or thinning, and further realizing excellent structural strength and fatigue resistance properties. [Brief explanation of the drawings]

[0004] For a better understanding of the above and other objects, features, advantages and functions of the present invention, reference can be made to the preferred embodiments illustrated in the drawings. The same reference numerals refer to the same elements throughout the drawings. Those skilled in the art should understand that the drawings are intended to schematically illustrate the preferred embodiments of the present invention and are not intended to limit the scope of the present invention, and that the components in the drawings are not drawn to scale. [Figure 1] FIG. 1 shows a three-dimensional view of a corrugated plate according to a preferred embodiment of the present invention. [Figure 2] FIG. 2 shows a top view of the corrugated plate shown in FIG. 1 as viewed from the height direction. [Figure 3] FIG. 3 is a side view of the corrugated plate shown in FIG. 1 viewed from a second direction. [Figure 4] FIG. 4 shows a side view of the corrugated plate shown in FIG. 1 viewed from a first direction. [Figure 5] FIG. 5 shows a cross-sectional view taken along line AA in FIG. [Figure 6] FIG. 6 shows a schematic diagram of a processing device for processing corrugated sheets according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0005] Specific embodiments of the present invention will be described in detail with reference to the drawings. The description herein is based on the preferred embodiments of the present invention, and those skilled in the art may conceive of other ways to realize the present invention based on the preferred embodiments, and such other ways are also included in the scope of the present invention.

[0006] The present invention provides a corrugated plate, preferably made of a metallic material (e.g., steel), applicable to the manufacture of storage vessels, in particular for storing liquefied gases such as liquefied natural gas (LNG), liquid nitrogen, liquid oxygen, liquid hydrogen, and liquid helium in marine or land-based engineering installations. A preferred embodiment of the corrugated plate will be described with reference to Figures 1 to 5.

[0007] As shown in FIG. 1 , the corrugated sheet 1 is processed from a flat metal sheet and includes a sheet body 11, first corrugations 12, and second corrugations 13. The first corrugations 12 and second corrugations 13 protrude outward from the sheet body 11 in a direction substantially perpendicular to the plane in which the sheet body 11 is located. This protruding direction can be referred to as the height direction D1. The protruding height (first height) of the first corrugations 12 from the sheet body 11 is greater than the protruding height (second height) of the second corrugations 13 from the sheet body 11. This protruding height refers to the maximum distance that the first corrugations 12 and second corrugations 13 protrude outward from the sheet body 11, i.e., the height of the crests. Furthermore, the first corrugations 12 extend along a first direction D2 on the sheet body 11. The second corrugations 13 extend along a second direction D3 on the sheet body 11. The first direction D2 and the second direction D3 are substantially perpendicular to each other. That is, the first waveform portion 12 and the second waveform portion 13 are substantially perpendicular to each other.

[0008] In some embodiments, both the first corrugation portion 12 and the second corrugation portion 13 may be configured as arc-shaped corrugations. For example, referring to FIGS. 3 and 4, when the first corrugation portion 12 and the second corrugation portion 13 are observed along their respective stretching directions, their projected outlines form arcs, with their respective apexes forming arcs and no corners. Of course, in other embodiments, at least one of the first corrugation portion and the second corrugation portion may be formed as a triangular corrugation portion. For example, when observed along their stretching directions, the projected outline of the corrugation portion may form an approximate triangle, with a corner at its apex. Here, the maximum width of the first corrugation portion 12 perpendicular to its stretching direction (first direction D2) is greater than the maximum width of the second corrugation portion 13 perpendicular to its stretching direction (second direction D3). In terms of characteristics such as height and width, the first corrugation portion 12 is also referred to as a large corrugation portion, and the second corrugation portion 13 is also referred to as a small corrugation portion.

[0009] The first corrugated portion 12 and the second corrugated portion 13 extend and intersect with each other, forming an intersecting structure 14 at the intersecting position. The intersecting structure 14 is advantageous for improving the structural strength of the corrugated plate 1 at the intersecting position and extending its lifespan.

[0010] The crossing structure 14 includes a peak 141 that protrudes outward from the center of the crossing position along the height direction D1 relative to the plate body 11. The protruding height of the peak 141 is greater than the protruding height of the first corrugation portion 12. Referring to FIG. 2, the first corrugation portion 12 and the second corrugation portion 13 are perpendicular to each other. Therefore, the first crest 121 of the first corrugation portion 12 and the second crest 131 of the second corrugation portion 13 can be regarded as two orthogonal coordinate axes, dividing the surrounding plate body 11 into four quadrants. The peak 141 can be regarded as the origin of the coordinate axes. Four ribs 142 extend from the peak 141 toward the plate body 11. Each quadrant has a rib 142. Referring to FIG. 2, the extension direction of each rib 142 intersects the first direction D2 and the second direction D3. 3, the extension direction of the ribs 142 also intersects with the height direction D1. In the process of forming the ribs at the intersections, the corrugated plate material is bent and protrudes outward, thereby forming the ribs.

[0011] According to the present invention, the crossing structure 14 further defines recesses 143. Similar to the ribs 142, there are four recesses 143, each located in one quadrant. In particular, the recesses 143 are provided on the outer surface of the first wave portion 12, and are located between the ribs 142 and the first crests 121 of the first wave portion 12. The recesses 143 are configured to be recessed inward relative to the outer surface of the first wave portion 12. That is, in the first wave portion 12, the recesses 143 are provided on both sides of the first crest 121. Meanwhile, the structure of the first crest 121 does not change and always maintains an outwardly protruding shape. That is, the height of the first crest 121 at the crossing structure 14 of the first wave portion 12 is the same as the height of the first crest 121 at other positions of the first wave portion 12, thereby maintaining the structural strength of the first wave portion 12 without being affected. Preferably, the recess depth of the recess 143 gradually increases from the outer edge toward the center.

[0012] During the corrugation process, material accumulation occurs in some locations of the sheet material while stretching occurs in others, resulting in uneven thickness. This adversely affects the sheet's strength. By providing the crests 141, ribs 142, and recesses 143, the cross structure 14 absorbs material accumulation at the crossing points during corrugation formation and distributes the accumulated material preferentially to the areas where the sheet is stretched. This uniformizes the line lengths of the upper and lower surfaces of the corrugated sheet at the crossing points, achieving uniform thickness and preventing excessive thickening or thinning. Metallographic analysis confirmed that this cross structure can achieve a maximum thickness reduction ratio of less than 5%, ensuring uniform material thickness and stable product performance. Furthermore, compared to conventional corrugated sheets with grooves on the crests, the technical objectives of the present invention enable superior structural strength and fatigue resistance. Finite element analysis revealed that the maximum strain of this cross structure under extreme conditions was 2%, which is significantly lower than the limit strain that causes structural damage to most metallic materials (for example, the uniaxial tensile limit strain that causes structural damage to stainless steel is usually 40% or more), ensuring the safety of the cross structure and the entire corrugated plate throughout its service life.

[0013] The ribs 142 extend from the tops 141 towards the plate body 11 and preferably terminate on the outer surfaces of the first corrugations 12 rather than all the way to the plate body 11. This is advantageous for maintaining the structural integrity of the plate body 11. Also, the smooth connection between the ribs 142 and the first corrugations 12 can increase the structural strength and at the same time avoid the occurrence of stress concentrations.

[0014] The outer surface of the first corrugations 12 is formed with recesses 143, which create a transition from an outwardly convex or flat to a concave shape, and this transition defines recess edges 144 of the recesses 143. In essence, this creates small, inconspicuous ribs on the outer surface of the first corrugations 12. This alternation of outer protrusions and inner recesses further enhances the structural strength of the cross structure 14 of the corrugated sheet 1.

[0015] Preferably, the recessed edge 144 smoothly connects and transitions between the rib 142 and the outer surface of the first corrugation 12. In other words, there is no clear connection between the recessed edge 144 and the rib 142, and therefore no abrupt change in shape occurs, which is advantageous in avoiding stress concentration. For ease of explanation, in FIGS. 2 and 3, the recessed edge 144 is symbolically represented by a curved scribed line, and the rib 142 is symbolically represented by a substantially straight scribed line. It should be understood that these dotted lines are used only to indicate the rough direction of the recessed edge 144 and the rib 142 and do not represent their actual shapes. Referring to FIGS. 2 and 3, the recessed edge 144 not only smoothly connects to the rib 142 at one end, but also extends toward the first crest 121 of the first corrugation 12. Whether viewed along the height direction D1 in FIG. 2 or along the second direction D3 in FIG. 3, the recessed edge 144 is configured as an outwardly protruding curve when projected onto the corresponding plane.

[0016] 2, in some embodiments, the angle formed by the tangent of the recessed edge 144 relative to the first direction D2 to the projected curved portion in a plane perpendicular to the height direction D1 is preferably smaller than the angle formed by the projection of the rib 142 relative to the first direction D2. The recessed edge 144 extends toward the first crest 121 of the first wave portion 12 while the angle formed by the tangent of the projected curved portion relative to the first direction D2 gradually increases. Furthermore, the dimension between both ends of the projected curved portion of the recessed edge 144 in the first direction D2 is greater than the dimension between both ends of the projection of the rib 142 in the first direction D2 (corresponding to the distance between the apex 141 and both connections of the recessed edge 144 and the rib 142 in the first direction D2).

[0017] In this manner, in the continuous protrusion structure formed by the recessed edge 144 and the rib 142, as the rib 142 extends, the distance between the first crest 121 of the first corrugation 12 in the first direction D3 gradually increases, reaching a maximum distance at the connection between the recessed edge 144 and the rib 142. Furthermore, as the recessed edge 144 extends toward the first crest 121, the distance between this continuous protrusion structure and the first crest 121 in the second direction D3 gradually decreases, converging to a minimum at the end of the recessed edge 144 away from the rib 142. Here, the extension amount of the rib 142 in the first direction D2 is smaller than the extension amount of the recessed edge 144 in the first direction D2. Therefore, when observed along the height direction D1 on the same side of the second corrugation 13, the ribs 142 and the corresponding recessed edges 144 located on both sides of the first corrugation 12 form a substantially heart-shaped pattern. Preferably, the crossing structures 14 have substantially the same shape in each quadrant, forming a symmetrical structure with respect to the first crest 121 of the first corrugation 12 and / or the second crest 131 of the second corrugation 13. Preferably, the recessed edges 144 extend to the first crest 121 of the first corrugation 12, and each recess 143 is surrounded by the corresponding rib 142, recessed edge 144 and first crest 121 of the first corrugation 12.

[0018] 3, on the same side of the first corrugation 12, a groove 145 is formed between two ribs 142 located on both sides of the second corrugation 13 above the second corrugation 13. Furthermore, referring to FIGS. 4 and 5, a groove bottom 146 of this groove 145 extends substantially along the height direction D1 (i.e., substantially perpendicular to the plate body 11). This structure is advantageous for improving the strength of the ribs 142 and the top 141 and increasing the load-bearing capacity perpendicular to the plate body 11.

[0019] FIG. 6 shows a processing device 2 for processing a corrugated sheet according to the present invention, particularly its cross structure. The processing device 2 includes a first mold 21, a pressure plate 22, a second mold 23, and an auxiliary forming member 24. It can be seen that the first corrugations 12 and the second corrugations 13 can be processed and shaped in two independent steps. The processing device 2 is used to further process a sheet material from which the first corrugations 12 have been pre-processed. The first mold 21 has an undercut groove 211. During processing, the pre-processed first corrugations 12 are placed in the undercut groove 211, and the sheet body 11 can be tightly attached to the upper surface of the first mold 21. Next, the pressure plate 22 is attached to the first mold 21. Preferably, the pressure plate 22 has a pressing protrusion that enters the first corrugations 12 and presses them against the undercut groove 211.

[0020] The first die 21 further includes forming grooves 212 for forming the second corrugations 13. Correspondingly, the second die 23 includes forming protrusions 231. When the sheet material is pressed against the first die 21, the second die 23 moves toward the first die 21, and the forming protrusions 231 push the sheet material into the forming grooves 212 to form the second corrugations 13. The middle portions of the forming protrusions 231 further include latches (not shown) that protrude outward under the action of elastic force (e.g., applied by a spring), and have a greater protruding distance than the forming protrusions 231. The latches press against the intersections of the first corrugations 12 and the second corrugations 13, cooperating with corresponding shapes in the forming grooves 212 to form the peaks 141, ribs 142, and grooves 145 of the intersection structures 14.

[0021] The auxiliary shaping member 24 is provided on the opposite side of the first mold 21 from the second mold 23, and has two auxiliary shaping protrusions 241, each located on either side of the shaping protrusion 231 of the second mold 23. Each auxiliary shaping protrusion 241 has a notch 242 at a position corresponding to the crest of the first waveform portion 12. The auxiliary shaping member 24 presses the sheet material in synchronization with the second mold 23. Here, the notch 242 creates a relief for the first crest 121 of the first waveform portion 12, and the two end points of the notch 242 press against the outer surface of the first waveform portion 12 on both sides of the first crest 121, thereby forming two recesses 143 and corresponding recess edges 144 on both sides of the first crest 121 of the first waveform portion 12. In this way, the processing of the corrugated sheet is completed.

[0022] The corrugated sheet according to the present invention can be used to form part of the wall of a storage container. In some embodiments, the wall of the storage container includes, in order from the outside to the inside, a secondary insulating layer, a secondary sealing layer, a primary insulating layer, and a primary sealing layer. That is, the primary sealing layer is located at the innermost part of the container wall and is in contact with the contents (e.g., LNG) in the storage container, and the secondary insulating layer is located at the outermost part. Here, both the secondary sealing layer and the primary sealing layer can be formed from the corrugated sheet according to the present invention. Furthermore, both the secondary insulating layer and the primary insulating layer are formed from insulating boards (e.g., plywood) made of a heat-insulating material. They can also be referred to as the secondary insulating layer and the primary insulating layer base layer.

[0023] The foregoing description of various embodiments of the present invention is provided for purposes of explanation to those skilled in the relevant art. It is not intended to be exhaustive or to limit the invention to a single disclosed embodiment. Various alternatives and modifications of the present invention will be apparent to those skilled in the art in light of the above teachings. Thus, while several alternative embodiments have been specifically described, those skilled in the art will understand or be able to develop relatively readily other embodiments. The present invention is intended to include all alternatives, modifications, and variations of the invention described herein, as well as other embodiments falling within the spirit and scope of the invention as described above.

[0024] Reference numerals in the drawings 1. Corrugated board; 11.Board body; 12.First waveform part; 121.First wave crest; 13.Second waveform part; 131.Second wave crest; 14. Cross structure; 141.Top; 142. Rib; 143. Recess; 144. Recessed edge; 145. Groove section; 146. Groove bottom; 2. Processing equipment; 21. First mold; 211.Relief groove; 212. Molding groove; 22.Pressure plate; 23. Second mold; 231. Molding protrusion; 24. Auxiliary forming members; 241.Auxiliary molding protrusion; 242.Notched section; D1. Height direction; D2. 1st direction; D3. Second direction.

Claims

1. A corrugated plate for a liquefied gas storage container, comprising: The corrugated plate includes a plate body (11), a first corrugated portion (12) and a second corrugated portion (13), wherein the first corrugated portion (12) protrudes at a first height relative to the plate body (11) along a height direction (D1) perpendicular to the plate body (11) and extends along a first direction (D2) parallel to the plate body (11), and the second corrugated portion (13) protrudes at a second height relative to the plate body (11) along the height direction (D1) and extends along a second direction (D2) parallel to the plate body (11). the first corrugations (12) extend along a second direction (D3), the first height is greater than the second height, the maximum width of the first corrugations (12) in a direction perpendicular to the first direction (D2) is greater than the maximum width of the second corrugations (13) in a direction perpendicular to the second direction (D3), the first corrugations (12) and the second corrugations (13) are perpendicular to each other and form crossing structures (14) at crossing positions, the crossing structures (14) including peaks (141), ribs (142) and recesses (143); The top (141) is located at the center of the intersection position, and the height of the top (141) protruding from the plate body (11) along the height direction (D1) is greater than the first height, There are four ribs (142), and each rib (142) is located in one of four quadrants formed by the perpendicular intersection of the first crest (121) of the first wave portion (12) and the second crest (131) of the second wave portion (13), and extends from the crest (141) toward the plate body (11). The overall extension direction of the rib (142) intersects with the first direction (D2), the second direction (D3), and the height direction (D1), respectively. There are four recesses (143), each of which is located in one of the four quadrants, formed on the outer surface of the first wave portion (12), and sandwiched between the first crest (121) of the first wave portion (12) and the rib (142), and the recesses (143) are recessed inward with respect to the outer surface of the first wave portion (12); wherein the recess (143) has a recess edge (144), the recess edge (144) being defined by a transition portion from an outwardly convex or flat to an inwardly concave portion on the outer surface of the first corrugation portion (12), the recess edge (144) extending from the rib (142) to the first crest (121) of the first corrugation portion (12), and thereby the recess (143) is surrounded by the rib (142), the recess edge (144) and the first crest (121) of the first corrugation portion (12).

2. 2. A corrugated plate according to claim 1, characterized in that said ribs (142) terminate at the outer surface of said first corrugation (12).

3. 3. A corrugated plate according to claim 2, characterized in that the ribs (142) smoothly connect and transition with the outer surfaces of the first corrugations (12).

4. 2. The corrugated sheet of claim 1, wherein said recessed edges (144) smoothly connect and transition with said ribs (142).

5. 2. The corrugated sheet according to claim 1, wherein the recess (143) has a depth that gradually increases from the edge of the recess (143) to the outer surface of the first corrugation (12) in a direction from the edge of the recess (143) toward the center of the recess (143).

6. 2. The corrugated sheet according to claim 1, wherein the height of the first crests (121) at the positions where the recesses (143) of the first corrugated portions (12) are formed is the same as the height of the first crests (121) at other positions of the first corrugated portions (12).

7. 2. The corrugated plate according to claim 1, wherein a groove (145) located above the second corrugation (13) is formed between two ribs (142) located on the same side of the first corrugation (12), and a groove bottom (146) of the groove (145) extends perpendicular to the plate body (11).

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