A thin film enclosure system air dome arrangement

Abstract

This invention discloses an air dome arrangement structure for a membrane enclosure system, comprising a membrane enclosure system and an air dome. The membrane enclosure system, from the outside in, includes a secondary insulation layer, a secondary shielding layer with mutually perpendicular first and second corrugations, a main insulation layer formed by splicing several main insulation boxes, and a main shielding layer with mutually perpendicular first and second main corrugations. The corrugations of the two shielding layers are parallel and their peaks are staggered. The air dome is located on the top wall of the membrane enclosure system. From the outside in, it has an outer cylinder connected to a supporting wall, a middle cylinder connected to the secondary shielding layer, and an inner cylinder that passes through the enclosure system and is fixedly connected to the main shielding layer. The inner cylinder is located at the intersection of the corrugations of the main shielding layer, and the middle cylinder is connected to the planar area enclosed by the corrugations of the secondary shielding layer. This design avoids deformation and stress superposition between the two corrugations, and the air dome passes through the secondary shielding layer without cutting the corrugations, improving the structural integrity and sealing reliability of the enclosure system.

Description

Technical Field

[0001] This invention relates to the field of cryogenic liquid cargo storage and transportation equipment technology, specifically to a membrane enclosure system with an air dome arrangement structure. Background Technology

[0002] The LNG membrane containment system is the core protective structure of cryogenic liquefied cargo storage tanks, consisting of two layers of metal membranes: a primary shielding layer and a secondary shielding layer. The primary shielding layer directly contacts the liquefied cargo, while the secondary shielding layer serves as a backup barrier in case the primary shielding layer fails. Together, these two layers form a double-redundant system for leak protection. Because LNG storage and transportation temperatures are as low as approximately -163°C, the metal membranes undergo significant thermal expansion and contraction during loading and unloading. Therefore, each membrane layer has a corrugated structure on its surface. The elastic deformation of the corrugations absorbs the displacement caused by thermal expansion and contraction, preventing damage to the membranes due to restricted deformation. The gas dome is a through-type structure within the containment system used for managing evaporated gases. It passes through each layer of the containment system in a direction perpendicular to the plane of the containment system, enabling the outlet of evaporated gases and pressure balance within the tank.

[0003] In existing technology, air domes are installed at the intersections of the main shielding layer corrugations and the secondary shielding layer corrugations. In this installation method, the corrugations of the main shielding layer and the secondary shielding layer coincide in a direction perpendicular to the plane of the enclosure system, and the intersections of the two corrugations are located on the same normal. When both the main and secondary shielding layer corrugations undergo contraction or expansion deformation, the deformation displacement and local bending stress of the two corrugations are superimposed at the same location; simultaneously, swaying impact loads also concentrate along the same normal direction at the overlapping crest position. These factors lead to a significant increase in the local stress level around the air dome, exacerbating fatigue damage to the membrane and welds, and easily causing cracks or even failure. In addition, when the air dome passes through the shielding layer, it needs to be installed by opening holes at the corrugation intersections, directly cutting off the structural continuity of the shielding layer corrugations, further weakening the thermal deformation compensation capacity of this area. Under long-term operating conditions, the above-mentioned stress superposition and corrugation damage problems seriously threaten the structural integrity and sealing reliability of the enclosure system, posing a risk of liquid leakage. Summary of the Invention

[0004] The purpose of this invention is to provide a dome arrangement structure for a membrane enclosure system. By staggering the corrugations of the primary and secondary shielding layers and the corresponding connection between the outer, middle, and inner cylinders of the dome and each layer, this invention solves the problems of stress superposition and fatigue cracking caused by the overlap of the two corrugations at the dome in the prior art, as well as the cutting off of the corrugations of the secondary shielding layer.

[0005] To address the aforementioned technical problems, the present invention provides a membrane enclosure system air dome arrangement structure, comprising: A membrane enclosure system, installed on a supporting wall, comprises, from the outside in, a secondary insulation layer adhered to the supporting wall, a secondary shielding layer having mutually perpendicular first and second corrugations, a primary insulation layer formed by splicing several primary insulation boxes, and a primary shielding layer fixed to the secondary insulation layer and having mutually perpendicular first and second primary corrugations. The first and second corrugations protrude towards the outer side of the membrane enclosure system and each has a first corrugation spacing. The first and second primary corrugations protrude towards the inner side of the membrane enclosure system and each has a second corrugation spacing. The first corrugation is parallel to the first primary corrugation, and the second corrugation is parallel to the second primary corrugation. The crests of the first and second corrugations are staggered from the crests of the first and second primary corrugations. An air dome is disposed on the top wall of the membrane enclosure system. The air dome is coaxially arranged from the outside to the inside as follows: an outer cylinder fixedly connected to the support wall, a middle cylinder connected to the secondary shielding layer, and an inner cylinder passing through the membrane enclosure system and fixedly connected to the main shielding layer. The inner cylinder is located at the intersection of the first main corrugation and the second main corrugation. The ends of the first main corrugation and the second main corrugation corresponding to the inner cylinder are sealed with plugs. The middle cylinder is connected to the planar area enclosed by the first corrugation and the second corrugation. The secondary shielding layer is provided with a through hole corresponding to the air dome. The circumference of the through hole is sealed to the outer circumference of the second flange edge at the end of the second flange sleeve. The inner cylinder extends outward from the position corresponding to the outside of the support wall with a secondary connecting platform. The secondary connecting platform is connected to a positioning cylinder connected to the second flange sleeve. The outer circumference of the secondary connecting platform is welded and fixed to the end of the middle cylinder.

[0006] Furthermore, the offset between the peak of the first corrugation and the peak of the first main corrugation, and the offset between the peak of the second corrugation and the peak of the second main corrugation, are both 1 / 2 of the greatest common divisor of the first wave spacing and the second wave spacing, and the inner cylinder is located at the center of the planar area enclosed by the first corrugation and the second corrugation.

[0007] Furthermore, the inner cylinder is located at the joint of the four main insulation boxes, and the top corners of the four main insulation boxes are cut to form receiving holes for accommodating the inner cylinder.

[0008] Furthermore, a compensation insulation box is provided at the splicing point of the four main insulation boxes. The compensation insulation box has a mounting hole corresponding to the outer diameter of the inner cylinder. The inner cylinder passes through the mounting hole and is welded and fixed to the main shielding layer.

[0009] Furthermore, a first flange sleeve is fitted at one end of the inner cylinder that is connected to the main shielding layer. The inner diameter of the first flange sleeve matches the outer diameter of the inner cylinder, and the first flange edge of the first flange sleeve is welded and fixed to the main shielding layer.

[0010] Furthermore, polyurethane foam is filled between the second flange sleeve and the inner cylinder, and glass wool is provided between the second flange sleeve and the secondary insulation layer.

[0011] Furthermore, a first gap exists between the inner circumference of the second flange edge and the inner cylinder.

[0012] Furthermore, a support platform is connected to the outer periphery of the middle part of the inner cylinder, and a third flange is provided on the outer periphery of the support platform along the height direction of the inner cylinder. The middle cylinder is fixedly connected to the third flange. A fourth flange is provided on the support platform along the radial direction of the inner cylinder, and a reinforcing rib is provided on the inner wall of the outer cylinder to cooperate with and connect with the fourth flange.

[0013] Furthermore, an air intake guide plate is connected to one end of the inner cylinder located inside the membrane enclosure system, and the air intake guide plate is fixedly connected to the outer periphery of the inner cylinder through a connecting strip.

[0014] The beneficial effects of this invention are: (1) The corrugations of the main shielding layer and the corrugations of the secondary shielding layer are staggered, and the inner cylinder of the air dome is located at the intersection of the corrugations of the main shielding layer and the middle cylinder is connected to the plane area of ​​the secondary shielding layer. This disperses the deformation displacement, local bending stress and swaying impact load of the two corrugations in space, avoids superposition at the same normal position, significantly reduces the local stress level around the air dome, alleviates the fatigue damage of the membrane and weld, and reduces the risk of crack initiation and propagation. (2) The middle cylinder is connected to the planar area enclosed by the first corrugation and the second corrugation. The through hole of the air dome through the secondary shielding layer is located in the planar area and does not involve the corrugated structure. This avoids the cutting of the corrugations of the secondary shielding layer in the prior art and fully maintains the structural continuity and thermal deformation compensation capability of the corrugations of the secondary shielding layer. (3) The air dome adopts a three-layer concentric cylinder structure of outer cylinder, middle cylinder and inner cylinder, which are respectively connected to the support wall, secondary shielding layer and main shielding layer to realize the graded transfer of load from the inside to the outside; the polyurethane foam between the second flange sleeve and the inner cylinder and the glass wool between the second flange sleeve and the secondary insulation layer ensure the insulation performance of the air dome penetration and cut off the thermal bridge at the air dome. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a partial structural schematic diagram of the present invention; Figure 3This is a schematic diagram showing the corresponding positions of the primary and secondary ripples in this invention; Figure 4 This is a cross-sectional view of the present invention; Figure 5 This is an enlarged view of the dome connection structure in this invention; Figure 6 This is a schematic diagram of an embodiment of the connection structure between the air dome and the main insulation layer of the present invention; Figure 7 This is a schematic diagram of Embodiment 2 of the connection structure between the air dome and the main insulation layer of the present invention.

[0016] Explanation of the labels in the diagram: 10. Supporting wall; 20. Membrane enclosure system; 21. Secondary insulation layer; 22. Secondary shielding layer; 221. First corrugation; 222. Second corrugation; 223. Planar area; 224. Through hole; 23. Primary insulation layer; 231. Primary insulation box; 232. Receiving hole; 233. Compensating insulation box; 234. Mounting hole; 24. Primary shielding layer; 241. First primary corrugation; 242. Second primary corrugation; 243. End cap; 30. Air dome; 31. Outer cylinder; 311. Reinforcing rib; 32. Middle cylinder; 321. Second flange sleeve; 322. Second flange edge; 323. Glass wool; 324. First gap; 33. Inner cylinder; 331. First flange sleeve; 332. First flange edge; 333. Secondary connecting platform; 334. Positioning cylinder; 335. Polyurethane foam; 336. Support platform; 337. Third flange; 338. Fourth flange; 339. Inlet guide plate. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0018] This embodiment provides a membrane containment system 20 with an air dome 30 arrangement, applicable to cryogenic liquid cargo storage and transportation equipment such as LNG ships or onshore cryogenic storage tanks. The membrane containment system 20 is used for the extraction and pressure management of evaporated gas at the top wall of the containment system. In this embodiment, the liquid cargo is liquefied natural gas, with a storage and transportation temperature of approximately -163°C. This invention is also applicable to the storage and transportation of other cryogenic liquid cargoes such as liquefied ethylene and liquefied petroleum gas.

[0019] Specifically, refer to Figure 1 As shown, the membrane enclosure system 20 is installed on the support wall 10, which serves as a structural component of the ship or a tank, and the support wall 10 bears the entire load of the enclosure system and the liquid cargo inside. The membrane enclosure system 20 includes, from the outside to the inside, a secondary insulation layer 21, a secondary shielding layer 22, a primary insulation layer 23, and a primary shielding layer 24.

[0020] The secondary insulation layer 21 is laid on the inner surface of the supporting wall 10 and is made of a material with good thermal insulation performance. It typically includes a secondary polyurethane block and secondary outer and inner plywood that hold the secondary polyurethane block in place. On the one hand, it blocks the transfer of external heat into the compartment, reducing the rate of evaporation gas generation; on the other hand, it evenly transfers the load of the enclosure system to the supporting wall 10. The thickness of the secondary insulation layer 21 is determined comprehensively based on the storage and transportation temperature, ambient temperature, and allowable heat leakage rate. In this embodiment, it is preferably 250 mm. A clearance structure is provided at the penetration point of the air dome 30, and the clearance range matches the size of the middle cylinder 32 of the air dome 30.

[0021] The secondary shielding layer 22 is laid on the side of the secondary insulation layer 21 away from the supporting wall 10. The secondary shielding layer 22 is a corrugated metal film with mutually perpendicular first corrugations 221 and second corrugations 222. The first corrugations 221 and second corrugations 222 of the secondary shielding layer 22 are mutually perpendicular and distributed in a grid pattern, with adjacent corrugations forming a planar region 223. The first corrugations 221 and second corrugations 222 protrude outward toward the outside of the membrane enclosure system 20, that is, toward the direction of the supporting wall 10, and both have a first corrugation spacing. The outward protrusion of the secondary corrugations causes the corrugated cavity opening to be away from the liquid cargo side, and the corrugations protrude toward the secondary insulation layer 21 and are supported by the secondary insulation layer 21, with continuous support at the root of the corrugations. In this corrugated structure, if there is a corrugation cutoff, it is not convenient to seal the corrugation end. On the other hand, after sealing the corrugation end with the sealing member, the sealing member protrudes from the surface of the secondary shielding layer 22, and there will also be a gap between the secondary shielding layer 22 and the secondary insulation layer 21 at the sealing point. Therefore, in this embodiment, the air dome 30 is set in the planar area 223 corresponding to the secondary shielding layer 22.

[0022] The main insulation layer 23 is formed by splicing together several main insulation boxes 231 and is laid on the side of the secondary shielding layer 22 away from the secondary insulation layer 21. The main insulation box 231 is a box-type insulation component, including a main polyurethane block and a main outer plywood and a main inner plywood that hold the main polyurethane block. The main insulation boxes 231 are spliced ​​together to form a continuous insulation barrier. The main insulation box 231 also serves as the supporting foundation for the main shielding layer 24, transferring the hydrostatic pressure and sway load of the liquid cargo borne by the main shielding layer 24 to the secondary shielding layer 22.

[0023] The main shielding layer 24 is fixed to the side of the main insulation layer 23 facing away from the secondary shielding layer 22. It is a corrugated metal film that directly contacts the liquid cargo inside the tank, and has a first main corrugation 241 and a second main corrugation 242 that are perpendicular to each other. The first main corrugation 241 and the second main corrugation 242 protrude towards the inside of the membrane enclosure system 20, that is, towards the liquid cargo inside the tank, and both have a second corrugation spacing. The first main corrugation 241 and the second main corrugation 242 are perpendicular to each other and distributed in a grid pattern on the surface of the main shielding layer 24, and the corrugations in the two directions intersect to form corrugation intersections.

[0024] Reference Figure 2 The diagram shows the structure between the primary and secondary shielding layers in this invention. The corrugations of the primary shielding layer 24 bulge inwards, while those of the secondary shielding layer 22 bulge outwards, are arranged in opposite directions, ensuring the two layers maintain a close, supportive relationship through the primary insulation layer 23. If the peaks of the two corrugations coincide on the same normal, their deformations will overlap at that location. To address this issue, the primary corrugations on the primary shielding layer 24 and the secondary corrugations on the secondary shielding layer 22 are staggered. Specifically, the first corrugation 221 is parallel to the first primary corrugation 241, and the second corrugation 222 is parallel to the second primary corrugation 242. The peaks of the first corrugation 221 and the first primary corrugation 241 are staggered, and the peaks of the second corrugation 222 and the second primary corrugation 242 are staggered. That is, the first corrugation 221 and the first main corrugation 241 are parallel corrugations extending in the same direction, and the second corrugation 222 and the second main corrugation 242 are parallel corrugations extending in the same direction. In the projection direction perpendicular to the plane of the enclosure system, the peaks of the secondary shielding layer 22 and the primary shielding layer 24 are not at the same normal position, that is, the peaks of the two corrugations are staggered. After the staggered setting, the intersection of the corrugations of the primary shielding layer 24 corresponds to the planar region 223 between the two corrugations of the secondary shielding layer 22 in the direction perpendicular to the plane of the enclosure system, rather than the intersection of the corrugations of the secondary shielding layer 22.

[0025] When the corrugations of the primary and secondary shielding layers 22 contract or expand with temperature changes, because the crests of the two layers are staggered, the deformation displacement at any location is only contributed by a single layer of corrugation, and the deformation displacements of the two layers no longer superimpose. The local bending stresses of the two corrugations are also distributed across different sections and no longer superimpose at the same location. When the swaying impact load is transmitted along the normal direction, it first acts on the first layer crest and is partially absorbed. When it reaches the second layer, it corresponds to the planar region 223, and the impact load is no longer concentrated at the same crest location. This spatial decoupling effect significantly reduces the local stress level around the air dome 30, alleviates fatigue damage to the membrane and welds, and reduces the risk of crack initiation and propagation.

[0026] Especially in the area through which the air dome 30 penetrates, the connection between the air dome 30 and each layer of shielding will generate local stress concentration at the connection point. If the intersection points of the two corrugations coincide on the same normal, the stress concentration at the hole edge, the corrugation bending stress, and the external load stress will be tripled at the same location, forming the hot spot area with the highest stress level in the entire enclosure system. The staggered arrangement of the present invention makes the penetration position of the air dome 30 at the secondary shielding layer 22 separate from the corrugation intersection point. The stress basis at the connection of the secondary shielding layer 22 is reduced from "the intersection of corrugations at the hole edge" to "the plane area 223 at the hole edge", and the stress level is significantly reduced.

[0027] Reference Figure 3 The diagram shows the corresponding positions of the primary and secondary corrugated plates in this invention. As a preferred configuration, in this embodiment, the offset between the peaks of the first corrugation 221 and the first primary corrugation 241, and between the peaks of the second corrugation 222 and the second primary corrugation 242, is half the greatest common divisor of the first and second wave spacing. Let G be the greatest common divisor of the first and second wave spacing. Since the two wave peaks only overlap when the offset is an integer multiple of G, setting the offset to G / 2 results in a minimum distance of G / 2 between the two wave peaks across the entire enclosure system. This means that the peaks of the primary shielding layer 24 and the secondary shielding layer 22 do not overlap at any location, achieving systematic offset across the entire enclosure. This offset is independent of the specific ratio of the two wave spacings. Regardless of the numerical relationship between the first and second wave spacings, the offset of G / 2 ensures that the two wave peaks do not overlap, making the solution universal. Furthermore, with the aforementioned staggered arrangement, the inner cylinder 33 is located at the center of the planar region 223 enclosed by the first corrugation 221 and the second corrugation 222. The center of the through hole 224 of the air dome 30 penetrating the secondary shielding layer 22 coincides with the center of the planar region 223. The edge of the through hole 224 maintains a uniform and maximum spacing with the surrounding corrugations of the secondary shielding layer 22, so that the deformation capability of the corrugations is not affected by the through hole 224, and the size of the through hole 224 has maximum margin.

[0028] Reference Figure 3 and Figure 4As shown, the air dome 30 passes through the top wall of the membrane enclosure system 20 and extends beyond the outer side of the top wall. The air dome 30 has an outer cylinder 31, a middle cylinder 32, and an inner cylinder 33 arranged concentrically from the outside in. These three cylinders are arranged coaxially, transferring load layer by layer from the inside out. The outer cylinder 31 is the outermost cylinder of the air dome 30 and is fixedly connected to the support wall 10. Anchored to the support wall 10, the outer cylinder 31 serves as a connecting component between the air dome 30 and the hull structure or load-bearing wall, providing overall positioning for the air dome 30 and transferring the external load borne by the air dome 30 to the support wall 10. The middle cylinder 32 is located between the outer cylinder 31 and the inner cylinder 33 and is connected to the secondary shielding layer 22. The middle cylinder 32 connects to the planar area 223 enclosed by the first corrugation 221 and the second corrugation 222. Because the corrugations of the primary and secondary shielding layers 22 are staggered, the intersection of the corrugations of the primary shielding layer 24 corresponds precisely to the planar region 223 of the secondary shielding layer 22 in the direction perpendicular to the plane of the enclosure system. The middle cylinder 32 is connected to the secondary shielding layer 22 at this planar region 223. Since the connection between the middle cylinder 32 and the secondary shielding layer 22 is located in the planar region 223, there is no need to drill holes at the corrugation intersection of the secondary shielding layer 22, avoiding cutting the corrugations of the secondary shielding layer 22 and completely preserving the structural continuity and thermal deformation compensation capability of the corrugations of the secondary shielding layer 22. The inner cylinder 33 passes through the membrane enclosure system 20 and is fixedly connected to the primary shielding layer 24. The inner cylinder 33 is located at the intersection of the first primary corrugation 241 and the second primary corrugation 242. The inner cylinder 33 is the main channel for evaporating gas; the evaporating gas inside the chamber is led out to the outside of the enclosure system through the inner cylinder 33. The connection between the inner cylinder 33 and the main shielding layer 24 makes full use of the structural characteristics of the corrugated intersection: the corrugated intersection is the meeting point of corrugations in two directions, and its structural rigidity is higher than that of the planar area 223, providing a reliable connection basis for fixing the inner cylinder 33.

[0029] Reference Figure 1 As shown, the first main corrugation 241 and the second main corrugation 242 are sealed at one end of the inner cylinder 33 by a plug 243. The corrugations are convex cavity structures on the film. If the ends are open, gas or liquid condensate will enter the internal cavity of the corrugations along the ends, affecting the deformation performance of the corrugations and causing leakage risks. After the ends of the corrugations are sealed by the plug 243, a closed cavity is formed inside the corrugations, ensuring that the corrugations absorb thermal expansion and contraction displacement only through their own elastic deformation, while preventing the medium from entering the corrugations. The outer contour of the plug 243 matches the shape of the opening at the end of the corrugations. The plug 243 is welded to the end of the corrugations, and the weld at the sealing point forms a continuous seal with the main shielding layer 24 body. After the inner cylinder 33 is penetrated at the intersection of the first main corrugation 241 and the second main corrugation 242, the ends of the corrugations in both directions are sealed, and a closed connection is formed between the corrugation intersection and the outer wall of the inner cylinder 33. The sealing barrier of the main shielding layer 24 at the penetration point of the air dome 30 is complete and continuous.

[0030] It should be noted that the air dome 30 is arranged concentrically from the outside in, consisting of an outer cylinder 31, a middle cylinder 32, and an inner cylinder 33, giving the air dome 30 an overall stepped, through-structure: the inner cylinder 33 is directly connected to the main shielding layer 24 and located at the corrugation intersection; the middle cylinder 32 is connected to the secondary shielding layer 22 at the plane area 223 of the secondary shielding layer 22; and the outer cylinder 31 is fixedly connected to the supporting wall 10. Each of the three cylinders is connected to its corresponding structural layer, and the connection positions are independent of each other in the direction perpendicular to the plane of the enclosure system. Assembly can be performed layer by layer from the outside in, reducing installation difficulty.

[0031] Reference Figure 5 As shown, a first flange sleeve 331 is fitted onto the end of the inner cylinder 33 that connects to the main shielding layer 24. The inner diameter of the first flange sleeve 331 matches the outer diameter of the inner cylinder 33. The first flange sleeve 331 is fitted onto the outer circumference of the end of the inner cylinder 33 and fits tightly therewith, specifically through sealing welding. The first flange edge 332 of the first flange sleeve 331 extends radially outward and is welded to the surface of the main shielding layer 24, achieving a sealed connection between the inner cylinder 33 and the main shielding layer 24. The welded seal ensures the airtightness and liquid tightness of the main shielding layer 24 at the penetration point of the air dome 30, preventing liquid leakage along the connection between the inner cylinder 33 and the main shielding layer 24. The first flange sleeve 331 distributes the connection load between the inner cylinder 33 and the main shielding layer 24 to the entire circumference of the first flange edge 332, avoiding stress concentration at local weld points.

[0032] During assembly, the first flange sleeve 331 is first fitted onto the end of the inner cylinder 33 and positioned. Then, the first flange sleeve 331 and the first flange edge 332 are welded to the corresponding corrugated intersection areas on the inner cylinder 33 and the main shielding layer 24, respectively. The welding is performed continuously along the outer periphery of the first flange edge 332 to form a circumferential seam. The installation of the first flange sleeve 331 changes the welding between the inner cylinder 33 and the main shielding layer 24 from direct butt welding to flange edge circumferential seam welding. The welding position is removed from the high strain zone of the membrane body, and the influence of the welding heat-affected zone on the corrugation deformation performance is limited to the local area of ​​the flange edge.

[0033] During assembly, the secondary insulation layer 21 and the secondary shielding layer 22 need to be laid first, and the middle cylinder 32 and the secondary shielding layer 22 need to be connected in the through hole 224 formed in the plane area 223 of the secondary shielding layer 22. Given that the middle cylinder 32 has a certain height, it is not convenient to install the inner cylinder 33 connected to the main shielding layer 24 after its installation. Therefore, a second flange sleeve 321 is provided in this embodiment. The outer periphery of the second flange edge 322 at the end of the second flange sleeve 321 is sealed to the through hole 224. At the same time, a secondary connecting platform 333 extends outward from the position of the inner cylinder 33 corresponding to the outer side of the support wall 10. The secondary connecting platform 333 is connected to a positioning cylinder 334 that connects to the second flange sleeve 321. The outer periphery of the secondary connecting platform 333 is welded and fixed to the end of the middle cylinder 32. The positioning cylinder 334 fits against the second flange sleeve 321, which on the one hand realizes the radial positioning between the inner cylinder 33 and the second flange sleeve 321, and ensures the concentricity between the cylinders of the air dome 30. On the other hand, during assembly, only the second flange sleeve 321 can be installed first, followed by the installation of the main insulation layer 23, the main shielding layer 24, and the inner cylinder 33. The second flange sleeve 321 is then welded and fixed to the positioning cylinder 334. After that, the end of the middle cylinder 32 is welded and fixed to the outer periphery of the secondary connecting platform 333, thereby realizing the connection between the middle cylinder 32 and the inner cylinder 33, as well as the indirect connection between the middle cylinder 32 and the secondary shielding layer 22.

[0034] Furthermore, the annular space between the second flange sleeve 321 and the inner cylinder 33 is filled with polyurethane foam 335 to block heat transfer along the wall of the air dome 30 into the cabin, cut off thermal bridges, and prevent the formation of localized cold loss concentration points at the penetration point of the air dome 30. Even further, to prevent cold leakage through the gap between the second flange sleeve 321 and the secondary insulation layer 21, glass wool 323 is also provided between the second flange sleeve 321 and the secondary insulation layer 21. Glass wool 323 is a flexible, low-temperature resistant insulation material that fills the gap between the second flange sleeve 321 and the secondary insulation layer 21, ensuring insulation performance while accommodating minor structural deformations.

[0035] Reference Figure 5 As shown, a first gap 324 exists between the inner circumference of the second flange edge 322 and the inner cylinder 33. The first gap 324 is the radial gap between the outer circumference of the inner cylinder 33 and the inner circumference of the second flange edge 322. When the main shielding layer 24 contracts or expands due to changes in the cabin temperature, the inner cylinder 33 is displaced along with the main shielding layer 24. Due to the existence of the first gap 324, the displacement of the inner cylinder 33 will not be transmitted to the second flange sleeve 321 and the secondary shielding layer 22, thereby achieving decoupling between the thermal deformation of the main shielding layer 24 and the structural deformation of the secondary shielding layer 22. This avoids additional stress around the through hole 224 and protects the reliability of the sealing connection between the secondary shielding layer 22 and the second flange edge 322.

[0036] To ensure the concentricity of the outer cylinder 31 with the inner cylinder 33 and the middle cylinder 32, a support platform 336 is connected to the outer periphery of the middle part of the inner cylinder 33. A third flange 337 is provided on the outer periphery of the support platform 336 along the height direction of the inner cylinder 33. The middle cylinder 32 is fixedly connected to the third flange 337, further connecting the middle cylinder 32 with the inner cylinder 33. Part of the load of the inner cylinder 33 is transferred to the middle cylinder 32 via the support platform 336 and the third flange 337. A fourth flange 338 is provided on the support platform 336 along the radial direction of the inner cylinder 33. A reinforcing rib 311 is provided on the inner wall of the outer cylinder 31, which is connected to the fourth flange 338. The fourth flange 338 is connected to the reinforcing rib 311, further transferring part of the load borne by the inner cylinder 33 and the middle cylinder 32 to the outer cylinder 31 and the support wall 10, realizing the graded transfer of the load of the air dome 30 from the inside to the outside. The reinforcing rib 311 also improves the structural rigidity of the outer cylinder 31, enhancing the overall load-bearing capacity of the air dome 30 under dynamic loads such as swaying and impact. The third flange 337 and the fourth flange 338 are respectively arranged along the height direction and the radial direction, so that the support platform 336 provides uniform circumferential support to the inner cylinder 33, preventing the inner cylinder 33 from tilting or becoming unstable under dynamic load, and ensuring that the displacement state of the connection end between the inner cylinder 33 and the main shielding layer 24 is coordinated with the deformation of the main shielding layer 24.

[0037] Reference Figure 6 The diagram shows the installation structure of the inner cylinder 33 in Embodiment 1 of the present invention. In this embodiment, the inner cylinder 33 is located at the junction of the four main insulation boxes 231. During installation, the adjacent apex corners of the four main insulation boxes 231 at the location of the air dome 30 are cut off respectively. The four cut apex corners together form a through receiving hole 232, through which the inner cylinder 33 passes and penetrates the main insulation layer 23. Compared with the avoidance method of cutting off the entire main insulation box 231, the apex corner cutting only causes local damage to the four main insulation boxes 231, and the main structure of each main insulation box 231 is intact, with minimal loss of insulation and load-bearing performance. The cut surface is flattened, and the remaining part of each main insulation box 231 after cutting still maintains the complete box structure and support capacity, making the process simple.

[0038] Reference Figure 7The diagram shows the installation structure of the inner cylinder 33 in Embodiment 2 of the present invention. Since there are gaps at the joints of the main insulation boxes 231, to avoid excessive gaps around the inner cylinder 33, in this embodiment, a compensating insulation box 233 is installed at the apex corner of the joint of the four main insulation boxes 231 after cutting. The compensating insulation box 233 has mounting holes 234 corresponding to the outer diameter of the inner cylinder 33, through which the inner cylinder 33 passes and is welded to the main shielding layer 24. The compensating insulation box 233 fills the gaps formed after the apex corners of the four main insulation boxes 231 are cut, ensuring the continuity of the main insulation layer 23 around the air dome 30 and preventing the formation of weak insulation areas at the air dome 30. The compensating insulation box 233 is tightly fitted to the surrounding main insulation boxes 231, and its insulation performance is comparable to that of the main insulation boxes 231, ensuring the overall continuity of the insulation layer of the enclosure system. The compensating insulation box 233 simultaneously forms a circumferential support around the inner cylinder 33, improving the local load-bearing capacity of the insulation layer at the penetration point of the air dome 30.

[0039] The overall installation process at the air dome 30 is as follows: First, the secondary insulation layer 21 and the secondary shielding layer 22 are laid, and a through hole 224 is formed on the plane area 223 of the secondary shielding layer 22; the second flange sleeve 321 is installed at the through hole 224 and a sealed connection is achieved; then the main insulation box 231 is spliced, and the four main insulation boxes 231 are cut at the top corners at the air dome 30 position and the compensation insulation box 233 is installed; then the inner cylinder 33 is passed through the mounting hole 234 of the compensation insulation box 233 and welded to the main shielding layer 24 through the first flange sleeve 331, and the end cap 243 of the corrugated end is sealed at the same time; finally, the connection between the middle cylinder 32 and the secondary layer connecting platform 333, the outer cylinder 31 and the supporting wall 10 and the supporting platform 336 are completed in sequence to form a complete air dome 30 arrangement structure.

[0040] Reference Figure 1 and Figure 5 As shown, one end of the inner cylinder 33, located inside the membrane enclosure system 20, is connected to an air inlet guide plate 339. After the inner cylinder 33 is inserted into the membrane enclosure system 20, the air inlet guide plate 339 is fixedly connected to the outer periphery of the inner cylinder 33 via a connecting strip, preventing the increase in the size of the end of the inner cylinder 33 from causing a gap between the inner cylinder 33 and the secondary insulation layer 21. The air inlet guide plate 339 is located in the area below the air inlet of the inner cylinder 33, guiding the rising and accumulating evaporating gas in the compartment, allowing the gas to enter the inner cylinder 33 smoothly, avoiding direct airflow impact on the port of the inner cylinder 33, which could cause local temperature fluctuations and structural vibrations. At the same time, it prevents droplets from entering the inner cylinder 33 with the gas, ensuring the dryness of the exported gas. When the ship's attitude changes, the liquid surface in the compartment sloshes, and the accumulation position of the evaporating gas changes accordingly. The guiding range of the air inlet guide plate 339 covers the area below the air inlet of the inner cylinder 33, and can rectify the gas entering the inner cylinder 33 under different liquid surface attitudes, ensuring a stable gas export flow rate from the air dome 30.

[0041] When the liquid cargo tank is in operation, the liquid cargo inside the tank continues to evaporate due to the influence of external heat, and the resulting evaporated gas accumulates at the top of the tank. As the evaporated gas rises, it is guided by the air inlet guide plate 339 and smoothly enters the inner cylinder 33. From there, it is discharged to the outside of the containment system through the channels of the inner cylinder 33 for reliquefaction or reuse as fuel. The air dome 30 also performs the function of managing the tank pressure, maintaining the tank pressure within a safe range. When changes in the ship's attitude cause sloshing of the liquid surface inside the tank, the sloshing impact load acts on the containment system. Because the primary and secondary shielding layers 22 are corrugated and staggered, the impact load is distributed across the two shielding layers to different locations, and no load concentration occurs around the air dome 30.

[0042] In the arrangement structure of the air dome 30 of the present invention: the corrugations of the main shielding layer 24 and the secondary shielding layer 22 are staggered; the inner cylinder 33 is located at the intersection of the corrugations of the main shielding layer 24; and the middle cylinder 32 is connected to the planar region 223 of the secondary shielding layer 22. The deformation displacement, local bending stress, and swaying impact load of the two corrugations are spatially dispersed, avoiding superposition at the same normal position and significantly reducing the local stress level around the air dome 30. The corrugations of the secondary shielding layer 22 are not cut, maintaining structural continuity and thermal deformation compensation capability. The compensation insulation box 233 ensures the continuity of the insulation layer at the air dome 30. The first gap 324 decouples the thermal deformation of the main shielding layer 24 from the deformation of the secondary shielding layer 22. The three-layer concentric cylinder structure achieves graded load transfer. The polyurethane foam 335 and glass wool 323 ensure the insulation performance at the penetration point of the air dome 30. The above technical effects jointly improve the structural integrity, sealing reliability, and insulation performance of the membrane enclosure system 20 at the penetration point of the air dome 30, reducing the risk of fatigue cracking and liquid leakage under long-term operating conditions.

[0043] The above-described embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A dome arrangement structure for a membrane enclosure system, characterized in that, include: A membrane enclosure system, installed on a supporting wall, comprises, from the outside in, a secondary insulation layer adhered to the supporting wall, a secondary shielding layer having mutually perpendicular first and second corrugations, a primary insulation layer formed by splicing several primary insulation boxes, and a primary shielding layer fixed to the secondary insulation layer and having mutually perpendicular first and second primary corrugations. The first and second corrugations protrude towards the outer side of the membrane enclosure system and each has a first corrugation spacing. The first and second primary corrugations protrude towards the inner side of the membrane enclosure system and each has a second corrugation spacing. The first corrugation is parallel to the first primary corrugation, and the second corrugation is parallel to the second primary corrugation. The crests of the first and second corrugations are staggered from the crests of the first and second primary corrugations. An air dome is disposed on the top wall of the membrane enclosure system. The air dome is coaxially arranged from the outside to the inside as follows: an outer cylinder fixedly connected to the support wall, a middle cylinder connected to the secondary shielding layer, and an inner cylinder passing through the membrane enclosure system and fixedly connected to the main shielding layer. The inner cylinder is located at the intersection of the first main corrugation and the second main corrugation. The ends of the first main corrugation and the second main corrugation corresponding to the inner cylinder are sealed with plugs. The middle cylinder is connected to the planar area enclosed by the first corrugation and the second corrugation. The secondary shielding layer is provided with a through hole corresponding to the air dome. The circumference of the through hole is sealed to the outer circumference of the second flange edge at the end of the second flange sleeve. The inner cylinder extends outward from the position corresponding to the outside of the support wall with a secondary connecting platform. The secondary connecting platform is connected to a positioning cylinder connected to the second flange sleeve. The outer circumference of the secondary connecting platform is welded and fixed to the end of the middle cylinder.

2. The membrane enclosure system air dome arrangement structure according to claim 1, characterized in that, The offset between the peak of the first corrugation and the peak of the first main corrugation, and the offset between the peak of the second corrugation and the peak of the second main corrugation, are both 1 / 2 of the greatest common divisor of the first wave spacing and the second wave spacing. The inner cylinder is located at the center of the planar area enclosed by the first corrugation and the second corrugation.

3. The air dome arrangement structure of the membrane enclosure system according to claim 1, characterized in that, The inner cylinder is located at the joint of the four main insulation boxes, and the top corners of the four main insulation boxes are cut to form receiving holes to accommodate the inner cylinder.

4. The membrane enclosure system air dome arrangement structure according to claim 3, characterized in that, A compensation insulation box is provided at the splicing point of the four main insulation boxes. The compensation insulation box has a mounting hole corresponding to the outer diameter of the inner cylinder. The inner cylinder passes through the mounting hole and is welded and fixed to the main shielding layer.

5. The air dome arrangement structure of the membrane enclosure system according to claim 1, characterized in that, A first flange sleeve is fitted at one end of the inner cylinder that is connected to the main shielding layer. The inner diameter of the first flange sleeve matches the outer diameter of the inner cylinder. The first flange edge of the first flange sleeve is welded and fixed to the main shielding layer.

6. The air dome arrangement structure of the membrane enclosure system according to claim 1, characterized in that, The space between the second flange sleeve and the inner cylinder is filled with polyurethane foam, and the space between the second flange sleeve and the secondary insulation layer is filled with glass wool.

7. The air dome arrangement structure of the membrane enclosure system according to claim 1, characterized in that, There is a first gap between the inner circumference of the second flange edge and the inner cylinder.

8. The air dome arrangement structure of the membrane enclosure system according to claim 1, characterized in that, A support platform is connected to the outer periphery of the middle part of the inner cylinder. A third flange is provided on the outer periphery of the support platform along the height direction of the inner cylinder. The middle cylinder is fixedly connected to the third flange. A fourth flange is provided on the support platform along the radial direction of the inner cylinder. A reinforcing rib is provided on the inner wall of the outer cylinder to cooperate with and connect with the fourth flange.

9. The air dome arrangement structure of the membrane enclosure system according to claim 1, characterized in that, An air intake guide plate is connected to one end of the inner cylinder located inside the membrane enclosure system. The air intake guide plate is fixedly connected to the outer periphery of the inner cylinder through a connecting strip.

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