A joint gap filling structure for a cryogenic cargo hold insulation panel

Abstract

The utility model discloses a kind of joint gap filling structures for low-temperature cargo hold insulation board, including flexible heat preservation sheet, protective cover and fixing part;Heat preservation sheet is embedded into the embedding slot formed by adjacent insulation board after folding, and the width of twice of heat preservation sheet thickness is greater than embedding slot;Protective cover is pressed to the end of heat preservation sheet and covers the notch of embedding slot, and fixing part is fixed on plywood on insulation board with protective cover.The utility model fills the joint gap of insulation board by setting heat preservation sheet, protective cover and fixing part, heat preservation sheet is embedded into embedding slot after folding, can guarantee heat preservation sheet to be tightly contacted on the two side walls of embedding slot;By fixing part, heat preservation sheet is pressed to protective cover, ensure that heat preservation sheet maintains reliable tight state, and position keeps stable.Therefore, the application can overcome the influence of external load, so that the filling structure is stably embedded in embedding slot, guaranteeing the dual functions of "absorbing tolerance" and "cold preservation".

Description

Technical Field

[0001] This utility model relates to the technical field of cryogenic liquid cargo tank insulation systems, and in particular to a joint gap filling structure for cryogenic cargo tank insulation panels. Background Technology

[0002] Liquefied natural gas (LNG) carriers are used to load and transport atmospheric pressure liquefied natural gas (LNG) under cryogenic conditions of -163°C. The insulation structure of its cargo tanks (also known as the "cargo tank containment system") is the most critical technical component of the entire vessel. It must simultaneously meet three major requirements: extremely low thermal conductivity for insulation and cold preservation; structural strength to withstand the static pressure and sloshing loads of the LNG cargo; and airtightness and leak-proof performance at cryogenic temperatures. This is to prevent LNG evaporation loss, external leakage, or cold embrittlement failure of the hull structural materials.

[0003] Currently, mainstream LNG carrier cargo tank containment systems are divided into two main categories based on their structural form: membrane type and freestanding type, with significant differences in their technical approaches. 1. Membrane Type Enclosure System Membrane-type containment systems are currently the most widely used structural form for large LNG carriers. Their characteristic is that they utilize the hull structure itself as support, with an extremely thin metal main wall and insulation layer laid inside. It consists of a main wall, secondary walls, and multiple layers of insulation materials. For example, in the Mark III Flex system, the main wall is welded from stainless steel corrugated plates using Invar steel (Ni36 alloy), which has an extremely low coefficient of thermal expansion. The secondary walls serve as a crucial safety barrier, with the space between the main and secondary walls filled with insulation materials such as perlite, polyurethane foam, and glass wool, forming multiple lines of protection.

[0004] 2. Independent Enclosure System Independent compartments possess a self-supporting tank structure, independent of the hull to bear liquid cargo loads. According to IMO standards, they are classified into Type A, Type B, and Type C. Type B compartments (prismatic / SPB compartments) are commonly used in large LNG carriers and are constructed using 9Ni steel or high-manganese austenitic cryogenic steel. They feature transverse baffles and longitudinal bulkheads to effectively suppress liquid sloshing. Their design requires complex fatigue crack propagation analysis, and partial secondary bulkhead protection is sufficient. Type C compartments are mostly cylindrical pressure vessels, suitable for small LNG carriers or fuel tanks. They typically do not require secondary bulkheads, have a simpler structure, but relatively lower volumetric utilization.

[0005] In both of the aforementioned systems, the thin-film type remains dominant due to its superior overall performance. It reduces daily evaporation rate (BOR) by blocking cold air leakage through a combination of multi-layered shielding and insulation layers. However, during actual construction and installation, to accommodate manufacturing tolerances of the insulation panels themselves, hull deformation tolerances, and installation tolerances, and to allow for installation operation space, a certain gap must be left at the joints between adjacent insulation panels. This gap objectively constitutes a cold bridge and air convection channel within the cabin, becoming a major bottleneck for heat leakage and increased BOR.

[0006] To compensate for this deficiency, such as Figure 1 As shown, existing processes often fill gaps with flexible insulation materials to achieve both tolerance absorption and cold insulation functions. However, under actual ship service conditions, these flexible filling materials are susceptible to compression creep, displacement, or even detachment due to external loads such as liquid cargo sloshing impact and alternating deformation of the hull. This leads to the recurrence of local cold bridges, a decrease in thermal insulation performance, and difficulty in achieving long-term reliable fixation in narrow compartments.

[0007] Therefore, in response to the technical problem of displacement failure of the inter-insulation panel filling structure in existing membrane-type (and extended to stand-alone) enclosure systems under complex marine loads, there is an urgent need for a new filling structure that can improve the long-term reliability of displacement resistance and impact resistance while achieving the dual functions of "tolerance absorption" and "cold preservation", thereby reducing LNG evaporation loss and improving the service safety of the enclosure system. Utility Model Content

[0008] This invention provides a joint gap filling structure for insulation panels in cryogenic cargo holds to solve the aforementioned technical problems.

[0009] To achieve the above objectives, the technical solution of this utility model is as follows: A joint gap filling structure for cryogenic cargo compartment insulation panels includes: a flexible insulation sheet, a protective cover, and a fastener; the insulation sheet is folded in half and embedded into an embedding groove formed by adjacent insulation panels, the thickness of the insulation sheet being twice the width of the embedding groove; the protective cover presses against the end of the insulation sheet and covers the opening of the embedding groove, and the fastener fixes the protective cover to the plywood on the insulation panel.

[0010] Preferably, the connected ends of the folded insulation sheet face the plywood on the lower surface of the insulation board, and the protective cover is fixed to the plywood on the upper surface of the insulation board.

[0011] Preferably, the embedded groove extends through the upper and lower surfaces of the insulation board, and the connected ends of the folded insulation sheet extend out of the plywood on the lower surface of the insulation board.

[0012] Preferably, the non-connected ends of the insulation sheet after folding extend beyond the upper surface of the insulation board but do not extend beyond the upper surface of the insulation board.

[0013] Preferably, the embedding groove extends from the middle of the insulation board to the upper surface of the insulation board, and the connected ends of the folded insulation sheet abut against the bottom of the embedding groove.

[0014] Preferably, the bottom width of the embedding groove is greater than the top width, and the bottom width of the embedding groove is less than twice the thickness of the insulation sheet.

[0015] Preferably, the non-connected ends of the insulation sheet after folding extend beyond the upper surface of the insulation board but do not extend beyond the upper surface of the insulation board.

[0016] Preferably, a first step surface is provided on the plywood on the upper surface of two adjacent insulation boards. The first step surface is located on the upper surface of the plywood and extends to the side of the plywood facing the adjacent plywood. The two sides of the lower surface of the protective cover abut against the two adjacent first step surfaces respectively, and the fastener fixes the protective cover to the plywood.

[0017] Preferably, a second step surface is provided on the plywood of the upper surface of one of the two adjacent insulation boards, and a third step surface is provided on the plywood of the upper surface of the other insulation board. The second step surface is located on the upper surface of the corresponding plywood and extends to the side of the corresponding plywood facing the adjacent plywood, and the third step surface is located on the lower surface of the corresponding plywood and extends to the side of the corresponding plywood facing the adjacent plywood. The protective cover includes a first fixing part, a pressing part, and a second fixing part. The first fixing part and the second fixing part are respectively fixed on both sides of the pressing part. The pressing part corresponds to the groove of the embedded groove. The second fixing part is located below the third step surface, and the first fixing part is located above the second step surface. The fastener fixes the first fixing part to the second step surface, and the third step surface presses the second fixing part.

[0018] Preferably, the insulation sheet is lined with glass wool, rock wool or flexible rubber and plastic foam, and covered with a polyvinyl chloride film.

[0019] Beneficial effects: This application discloses a gap-filling structure for joints of cryogenic cargo compartment insulation panels. The structure fills the gaps between the insulation panels by using insulation sheets, protective covers, and fasteners. The insulation sheet is folded in half and embedded into an embedded groove added to an adjacent insulation panel, ensuring that twice the thickness of the insulation sheet is greater than the width of the groove. This guarantees that the insulation sheet is taut and pressed against the side walls of the groove. The protective cover is then secured with fasteners to further tighten the insulation sheet, ensuring it remains reliably taut and its position is stable. Therefore, this application overcomes the effects of external loads, allowing the filling structure to be stably embedded in the groove, ensuring both tolerance absorption and cold insulation functions. It also improves long-term reliability against displacement and impact, thereby reducing LNG evaporation loss and enhancing the service safety of the containment system. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of a membrane-type enclosure system; Figure 2 This is a schematic diagram of the first type of splicing of two adjacent insulation boards for a joint gap filling structure for a cryogenic cargo compartment insulation board disclosed in Embodiment 1 of this utility model. Figure 3 This is a schematic diagram of the splicing of two adjacent insulation boards in a joint gap filling structure for a cryogenic cargo hold insulation board, as disclosed in Embodiment 1 of this utility model. Figure 4 This is a schematic diagram of an assembled insulation sheet for filling the joint gap of a cryogenic cargo hold insulation panel, as disclosed in Embodiment 1 of this utility model. Figure 5 This is a schematic diagram of a second protective cover structure for filling the joint gap of a cryogenic cargo hold insulation board, as disclosed in Embodiment 1 of this utility model. Figure 6 This is a schematic diagram of the splicing of two adjacent insulation boards in a joint gap filling structure for a cryogenic cargo hold insulation board, as disclosed in Embodiment 2 of this utility model. Figure 7 This is a schematic diagram of the first protective cover structure for filling the joint gap of a cryogenic cargo compartment insulation board, as disclosed in Embodiment 2 of this utility model.

[0022] In the picture: 1. Insulation sheet; 2. Protective cover; 21. First fixing part; 22. Pressing part; 23. Second fixing part; 3. Fasteners; 4. Insulation board; 41. Embedded groove; 5. Plywood; 51. First step surface; 52. Second step surface; 53. Third step surface. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0024] Example 1 A joint gap filling structure for cryogenic cargo compartment insulation panels, combined with Figure 2 - Figure 5 As shown, the device includes: a flexible insulation sheet 1, a protective cover 2, and a fastener 3; the insulation sheet 1 is folded in half and embedded into an embedding groove 41 formed by adjacent insulation boards 4, with the thickness of the insulation sheet 1 being twice the width of the embedding groove 41; the protective cover 2 presses against the end of the insulation sheet 1 and covers the opening of the embedding groove 41; the fastener 3 fixes the protective cover 2 to the plywood 5 on the insulation board 4. This application fills the gaps in the joints of the insulation boards 4 by setting the insulation sheet 1, the protective cover 2, and the fastener 3. The insulation sheet 1 is folded in half and embedded into the embedding groove 41 added to the adjacent insulation board 4, so that twice the thickness of the insulation sheet 1 is greater than the width of the embedding groove 41, ensuring that the insulation sheet 1 is taut and abuts against the two side walls of the embedding groove 41; then the protective cover 2 is fixed by the fastener 3 to press the insulation sheet 1, ensuring that the insulation sheet 1 maintains a reliable taut state and a stable position. Therefore, this application can overcome the influence of external loads, so that the filling structure is stably embedded in the embedding groove, ensuring the dual functions of "tolerance absorption" and "cold preservation", improving the long-term reliability of anti-displacement and anti-impact, thereby reducing LNG evaporation loss and improving the service safety of the enclosure system.

[0025] Preferably, the connected ends of the folded insulation sheet 1 (the continuous ends formed by the middle position of the insulation sheet 1 when it is not folded) face the plywood 5 on the lower surface of the insulation board 4, that is, the non-connected ends of the folded insulation sheet 1 (the overlapping but not integrated ends formed by the two ends of the insulation sheet 1 when it is not folded) face the upper surface of the insulation board 4, and the protective cover 2 is fixed to the plywood 5 on the upper surface of the insulation board 4. The connected ends of the folded insulation sheet 1 can prevent the airflow from the lower part from flowing upward, and the protective cover 2 pressing the non-connected ends of the folded insulation sheet 1 can enhance the outward expansion effect of the insulation sheet 1 and prevent the airflow from the upper part from flowing downward.

[0026] Preferably, the embedding groove 41 extends from the middle of the insulation board 4 to the upper surface of the insulation board 4, and the connected end of the folded insulation sheet 1 abuts against the bottom of the embedding groove 41, thereby defining the position of the connected end of the folded insulation sheet 1 by the bottom of the embedding groove 41.

[0027] Specifically, the insulation board 4 is glued to the upper and lower surfaces to fix the plywood 5, which is a purchased finished product and will not be described in detail here. This application adds a stepped structure to the upper half of the side of the insulation board 4, with the corresponding plywood 5 aligned with the edge of the upper surface of the insulation board 4; after adjacent insulation boards 4 are joined, a gap is left in the lower half of the side of the insulation board 4, and the two stepped structures fit together to form an embedding groove 41. The insulation sheet 1 is inserted into the embedding groove 41, and the two folded sides of the insulation sheet 1 abut against the two side walls of the embedding groove 41, which can effectively block the flow of cold air at the joint gap of the insulation board 4. Furthermore, by making the thickness T of the insulation sheet 1 twice greater than the width G of the embedding groove 41, i.e., 2T > G, it is ensured that the two folded sides of the insulation sheet 1 are pressed tightly against the two side walls of the embedding groove 41, ensuring reliable sealing.

[0028] Preferably, the non-connected end of the folded insulation sheet 1 extends beyond the upper surface of the insulation board 4 but does not extend beyond the plywood 5 on the upper surface of the insulation board 4. This ensures that the protective cover 2, after being fixed, fully presses the non-connected end of the folded insulation sheet 1, and ensures that the non-connected end of the folded insulation sheet 1 abuts against the side wall of the embedded groove 41 and the side walls of the two plywood 5 above.

[0029] Preferably, the bottom width of the embedding groove 41 is greater than the top width, and the bottom width of the embedding groove 41 is less than twice the thickness of the insulation sheet 1. That is, the bottom of the embedding groove 41 widens to both sides but can still compress the folded insulation sheet 1. When the insulation sheet 1 is folded and inserted and pressed by the protective cover 2, the connected end of the folded insulation sheet 1 is tightened and embedded in the bottom of the embedding groove 41, which can ensure the stability of the connected end of the folded insulation sheet 1 and achieve the effect of sealing the insulation sheet 1 against the side wall of the embedding groove 41.

[0030] Preferably, a first stepped surface 51 is provided on the plywood 5 on the upper surface of two adjacent insulation boards 4. The first stepped surface 51 is located on the upper surface of the plywood 5 and extends to the side of the plywood 5 facing the adjacent plywood 5. The two sides of the lower surface of the protective cover 2 respectively abut against the two adjacent first stepped surfaces 51, and the fastener 3 fixes the protective cover 2 to the plywood 5. This allows the protective cover 2 to be stably fixed to the plywood 5, and the structure allows the upper surface of the protective cover 2 to be flush with the upper surface of the plywood 5.

[0031] Specifically, the fastener 3 uses screws, and the two sides of the long protective cover 2 are tightened and fixed to the two first step surfaces 51 by a set of screws, so as to avoid the protective cover 2 directly applying force to the insulation board 4.

[0032] It is understandable that a protective cover structure with single-sided screw fixing can also be used. One of the two adjacent insulation boards 4 has a second stepped surface 52 on the upper surface of the plywood 5, and the other insulation board 4 has a third stepped surface 53 on the upper surface of the plywood 5. The second stepped surface 52 is located on the upper surface of the corresponding plywood 5 and extends to the side of the corresponding plywood 5 facing the adjacent plywood 5. The third stepped surface 53 is located on the lower surface of the corresponding plywood 5 and extends to the side of the corresponding plywood 5 facing the adjacent plywood 5. That is, the second stepped surface 52 is upward and the third stepped surface 53 is downward, and the third stepped surface 53 forms a groove with the upper surface of the insulation board 4.

[0033] The protective cover 2 includes a first fixing part 21, a pressing part 22, and a second fixing part 23. The first fixing part 21 and the second fixing part 23 are respectively fixed on both sides of the pressing part 22. The pressing part 22 corresponds to the groove of the insertion slot 41. The second fixing part 23 is located below the third step surface 53, and the first fixing part 21 is located above the second step surface 52. The fastener 3 fixes the first fixing part 21 on the second step surface 52, and the third step surface 53 presses against the second fixing part 23. The above structure can achieve the second fixing part 23 being pressed and fixed after insertion, and the first fixing part 21 being fixed by a set of screws; it can save materials and simplify assembly, thereby saving costs.

[0034] Specifically, the first fixing part 21, the pressing part 22, and the second fixing part 23 are integrally formed. The first fixing part 21 is located on one side of the pressing part 22. The upper surface of the first fixing part 21 is flush with the upper surface of the pressing part 22, and the lower surface of the first fixing part 21 is higher than the lower surface of the pressing part 22. The thickness of the first fixing part 21 matches the depth of the second step surface 52. The second fixing part 23 is located on the other side of the pressing part 22. The lower surface of the second fixing part 23 is flush with the lower surface of the pressing part 22, and the upper surface of the second fixing part 23 is lower than the upper surface of the pressing part 22. The thickness of the second fixing part 23 matches the depth of the third step surface 53. The upper surface of the second fixing part 23 abuts against the third step surface 53, and the lower surface of the second fixing part 23 abuts against the upper surface of the insulation board 4. The upper surface of the first fixing part 21 is flush with the upper surface of the plywood 5, and the lower surface of the first fixing part 21 abuts against the second step surface 52.

[0035] Specifically, the upper surface of the insulation board 4 corresponding to the third step surface 53 is machined downward to form a step, thereby increasing the distance between the third step surface 53 and the insulation board 4, and thus increasing the thickness of the second fixing part 23 to ensure the rigidity of the structure; at the same time, it can increase the compression length of the non-connected end of the insulation sheet 1 after the pressing part 22 is folded, thereby strengthening the effect of the insulation sheet 1 to tighten and seal.

[0036] Preferably, the insulation sheet 1 is lined with glass wool, rock wool, or flexible rubber-plastic foam, and covered with a polyvinyl chloride film. The polyvinyl chloride film helps maintain its shape and blocks the flow of cold air.

[0037] Example 2 The difference between this embodiment and Embodiment 1 is that the embedded groove 41 is a through groove.

[0038] Preferably, combined with Figures 2-7 As shown, the embedding groove 41 extends through the upper and lower surfaces of the insulation board 4. No additional step structure is needed on the side of the insulation board 4; the embedding groove 41 is formed directly by increasing the gap between adjacent insulation boards 4. The connected end of the folded insulation sheet 1 extends beyond the plywood 5 on the lower surface of the insulation board 4. After the insulation sheet 1 is compressed and expanded, a protrusion forms at the connected end of the folded insulation sheet 1, defining the position of the connected end of the folded insulation sheet 1.

[0039] Preferably, the non-connected end of the folded insulation sheet 1 extends beyond the upper surface of the insulation board 4 but does not extend beyond the plywood 5 on the upper surface of the insulation board 4. This ensures that the protective cover 2, after being fixed, fully presses the non-connected end of the folded insulation sheet 1, and ensures that the non-connected end of the folded insulation sheet 1 abuts against the side wall of the embedded groove 41 and the side walls of the two plywood 5 above.

[0040] In practical applications, the structures of Embodiments 1 and 2 of this application can be selected for filling based on the space available below the upper and lower insulation layers. For example, if a secondary screen wall is fixed under the plywood below the upper insulation layer, and the lower insulation layer is fixed below the secondary screen wall, and there is no space below to accommodate the folded, connected ends of the protruding insulation sheet 1, the fully inserted structure of Embodiment 2 cannot be used. In this case, the semi-inserted structure of Embodiment 1 can be used. The structure of this application not only reduces cargo loss during LNG ship operation but also facilitates installation and reduces costs, thus helping to improve the system's price competitiveness.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A joint gap filling structure for cryogenic cargo hold insulation panels, characterized in that, include: A flexible insulation sheet (1), a protective cover (2), and a fastener (3); the insulation sheet (1) is folded in half and embedded in the embedding groove (41) formed by the adjacent insulation board (4), and the thickness of the insulation sheet (1) is twice the width of the embedding groove (41); the protective cover (2) presses the end of the insulation sheet (1) and covers the opening of the embedding groove (41), and the fastener (3) fixes the protective cover (2) to the plywood (5) on the insulation board (4).

2. The joint gap filling structure for cryogenic cargo hold insulation panels according to claim 1, characterized in that, The connected ends of the folded insulation sheet (1) face the plywood (5) on the lower surface of the insulation board (4), and the protective cover (2) is fixed on the plywood (5) on the upper surface of the insulation board (4).

3. The joint gap filling structure for cryogenic cargo hold insulation panels according to claim 2, characterized in that, The embedded groove (41) penetrates the upper and lower surfaces of the insulation board (4), and the connected end of the insulation sheet (1) after being folded out extends out of the plywood (5) on the lower surface of the insulation board (4).

4. The joint gap filling structure for cryogenic cargo hold insulation panels according to claim 2, characterized in that, The embedding groove (41) extends from the middle of the insulation board (4) to the upper surface of the insulation board (4), and the connected end of the folded insulation sheet (1) abuts against the bottom of the embedding groove (41).

5. A joint gap filling structure for cryogenic cargo hold insulation panels according to claim 4, characterized in that, The bottom width of the embedding groove (41) is greater than the top width, and the bottom width of the embedding groove (41) is less than twice the thickness of the insulation sheet (1).

6. A joint gap filling structure for cryogenic cargo hold insulation panels according to claim 3 or 4, characterized in that, The non-connected end of the insulation sheet (1) extends out of the upper surface of the insulation board (4) but does not extend out of the upper surface of the plywood (5).

7. A joint gap filling structure for cryogenic cargo hold insulation panels according to claim 2 or 4, characterized in that, The upper surfaces of the two adjacent insulation boards (4) are provided with a first step surface (51) on the plywood (5). The first step surface (51) is located on the upper surface of the plywood (5) and extends to the side of the plywood (5) facing the adjacent plywood (5). The two sides of the lower surface of the protective cover (2) respectively abut against the two adjacent first step surfaces (51). The fastener (3) fixes the protective cover (2) on the plywood (5).

8. A joint gap filling structure for cryogenic cargo hold insulation panels according to claim 2 or 4, characterized in that, A second step surface (52) is provided on the plywood (5) on the upper surface of one of the two adjacent insulation boards (4), and a third step surface (53) is provided on the plywood (5) on the upper surface of the other insulation board (4). The second step surface (52) is located on the upper surface of the corresponding plywood (5) and extends to the side of the corresponding plywood (5) facing the adjacent plywood (5). The third step surface (53) is located on the lower surface of the corresponding plywood (5) and extends to the side of the corresponding plywood (5) facing the adjacent plywood (5). The protective cover (2) includes: a first fixing part (21), a pressing part (22) and a second fixing part (23). The first fixing part (21) and the second fixing part (23) are respectively fixed on both sides of the pressing part (22). The pressing part (22) corresponds to the groove of the embedded groove (41). The second fixing part (23) is located below the third step surface (53). The first fixing part (21) is located above the second step surface (52). The fixing member (3) fixes the first fixing part (21) on the second step surface (52). The third step surface (53) presses the second fixing part (23).

9. A joint gap filling structure for cryogenic cargo hold insulation panels according to claim 2, characterized in that, The insulation sheet (1) is made of glass wool, rock wool or flexible rubber and plastic foam, and is covered with a polyvinyl chloride film.

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