JP3111657U - Dome end of ultra vacuum insulation tank for cryogenic liquefied gas - Google Patents

Abstract

A dome end of an inner container of a tank and an ultra-vacuum heat insulation tank using the dome end are provided.
The tank includes a frame structure and a tank body, and the tank body includes an outer shell, an inner container, and a composite support structure that connects the outer shell and the inner container. The composite support structure is provided only at both ends of the tank, between the dome end of the outer shell and the dome end of the inner container, so that it can withstand both latitudinal and longitude forces. The heat transfer surface between the inner container and the outer shell is small, yet the support structure can withstand heavy loads and the effective load capacity of the inner container is large.
[Selection] Figure 3

Description

  The present invention relates to a kind of cryogenic liquefied gas storage facility or transport facility, and more particularly, an ultra-vacuum using the dome end of the inner container and the dome end for efficiently transporting the cryogenic liquefied gas. It relates to an insulation tank.

  The performance of the cryogenic tank has been dramatically improved by the vacuum powder insulation technology invented in 1909. Vacuum powder insulation technology has become widely used in all fields of cryogenic technology during the past 30 years. A typical example is air separation liquefaction technology. About 50 years ago, ultra-vacuum multilayer insulation technology appeared. This was a very important development in the history of cryogenic thermal insulation technology. In particular, during the past 50 years, with the development of space technology, the consumption of liquid hydrogen and liquid helium has increased rapidly, which has motivated research and application of ultra-vacuum multilayer insulation technology. Its main application products were tank cars and tank containers for cryogenic liquefied gas.

  In the field of cryogenic technology, a cryogenic liquefied gas is a gas in a liquid state at a temperature below −160 ° C., for example, liquefied oxygen, liquefied nitrogen, liquefied argon, liquefied hydrogen, liquefied helium, liquefied methane. And liquefied natural gas (LNG). These gases are often transported in the liquid state because their volume in the liquid state is less than 1/600 of the volume in the gas state. Examples of cryogenic liquefied gas transportation facilities include tank cars and tank containers. The tank has a double structure, and a vacuum intermediate layer is disposed between the inner container and the outer shell connected by the support structure. Due to the requirements of transport regulations, all transport equipment (such as tank cars and tank containers) must comply with the maximum overall size limit, and the effective load capacity is determined by the thickness of the vacuum layer within that limit .

  Currently, vacuum powder insulated tank cars and tank containers are widely used as cryogenic transport facilities. FIG. 1 shows the main structure of a transport facility 10 according to the related art. This structure consists of an outer shell 1, an inner container 2, a thermal insulation structure 3, a plurality of radial supports 4 and front and rear longitudinal supports 15 and 16 between the outer shell 1 and the inner container 2. And a rigid assembly 6. An ultra-vacuum layer 8 is formed between the inner container 2 and the outer shell 1, and a material such as pearlite can be added therein to achieve heat insulation. In order to achieve a sufficient thermal insulation effect, the vacuum layer 8 is designed to have a large thickness (usually in the range of 200 to 300 mm). However, such a facility sacrifices the maximum loading capacity, and perlite gradually sinks during transportation, which adversely affects the heat insulation performance. Therefore, multilayer insulation technology was developed. This has improved the practicality of equipment for transporting cryogenic liquefied gas.

  In the multilayer heat insulation technique, a heat insulation layer is formed by winding a heat insulation material around the outer side of the inner container 2 in the transport facility 10 described above, and turning a vacuum intermediate layer made of a plurality of layers of heat insulation material into a super vacuum state with a pump. The thinner the vacuum intermediate layer, the larger the tank load, but there are problems. That is, the thinner the heat insulating layer, the more difficult it is to install the support structure between the inner container and the outer shell. Further, the thinner the heat insulating layer, the lower the degree of vacuum and the more heat transferred from the inner container to the outer shell.

  For example, as disclosed in Chinese Patent Nos. ZL 00249960.6 and ZL 01272605.2, most current multi-layer insulation techniques are used to install a radial support in the vacuum layer. The thickness of the vacuum layer must be about 100 mm.

  In fact, the support structure between the inner container and the outer shell not only can withstand the load from the liquid, the weight of the tank, and the force generated by the acceleration of the impact, but also allows heat leakage due to the support structure itself. It is also necessary to reduce as much as possible. Therefore, the design of the cryogenic tank support structure is important. This support structure includes a radial support 4, a front longitudinal support 15, and a rear longitudinal support 16 in the aforementioned transport facility. Taking the rear longitudinal support 16 as an example, the support 16 is composed of an inner vessel reinforcing plate 23 and a supporting steel pipe 24, a heat insulation auxiliary ring 26 and its holding ring 25, an outer shell supporting steel pipe 32, and a reinforcement. Ribs 33 are included. The inner container support steel pipe 24 is welded to the outer surface of the rear dome end of the inner container 2 via the reinforcing plate 23, and the outer shell support steel pipe 32 is attached to the inner surface of the rear dome end of the outer shell 1. Welded. The inner container support steel pipe 24 is held by the outer shell support steel pipe 32 via the heat insulation auxiliary ring 26 and the pressing ring 25. The rigid assembly 6 includes a heat insulating filling block 28, an inner nut 27 and a compression nut 29 of the heat insulating filling block 28, a support shaft pin 30, and a support lid 31. The rigid assembly 6 is connected to the support steel pipe 24 via the inner nut 27. The compression nut 29 is welded to the support lid 31. The support lid 31 is welded to the outer shell support steel pipe 32. In the above-described structure of the heat insulating filling block between the inner container and the outer shell, the gap between the plurality of ultra-vacuum heat insulating layers is narrow, so that the heat leakage due to the support structure is very large. It is clear that the problems of damage to multiple ultra-vacuum thermal insulation layers due to expansion and low temperature shrinkage and failure of the layers cannot be effectively solved. Also, it is very difficult to provide a stainless steel sleeve tube between the dome end of the inner container and the dome end of the outer shell. Furthermore, since the distance between the dome end of the inner container and the dome end of the outer shell is large, the impact resistance is low.

  Some cryogenic container support structures are called “suspender” structures, but this cannot effectively overcome the problem of reduced impact resistance due to thermal expansion and cold shrinkage. Increasing the support capacity of stainless steel suspenders increases the heat transferred, resulting in increased vaporization losses in cryogenic containers and reduced cryogenic liquid storage efficiency.

  Chinese Patent No. ZL 00216678. No. X discloses a support structure 40 that can withstand the strong impact of a cryogenic container, as shown in FIG. The support structure 40 includes a radial support provided on the inner surface of the outer shell at each end of the cryogenic container, and a longitudinal support provided at one end of the cryogenic container, The other end of the cryocontainer is a free end. The radial support includes a radial support ring 41, an outer shell support tube 42, and reinforcing ribs 43. One end of the support tube 51 of the inner container is welded to the center of the outer surface of each dome end of the inner container 50, and the other end is fitted into the radial support ring 41. The support tube 42, the reinforcing rib 43, and the outer shell 44 are fixed integrally. The longitudinal support is attached to each end of the longitudinal support bar 47, the longitudinal support plate 47 which is connected to the support tube 51 by screws and positioned by welding, and the longitudinal support plate 47. The glass reinforced plastic support plate 46, the holding steel band 48 that strongly presses the glass reinforced plastic support plate 46 in cooperation with the longitudinal support plate 47, and the longitudinal stand bar 45 at the dome end of the outer shell 44. And a dissimilar material joint 49 for welding. In the case of this support structure, the distance between the dome end and the dome end is large because both radial and longitudinal support structures are provided at each end of the cryogenic container. is there. For this reason, the impact resistance becomes weak and the contact gap widens during the transition from normal temperature to low temperature.

  With the advancement of cryogenic liquefied gas storage tanks and transport tanks, it is necessary to effectively increase the effective capacity for cryogenic liquefied gas and effectively improve impact resistance within the limited overall dimensions. It is done.

  Therefore, an object of the present invention is to provide a dome end structure having a small dome end in the opposite direction in the center for arranging the support structure. This substantially avoids design problems in accordance with the related art, and achieves a superior thermal insulation performance by making the tank thermal insulation layer thinner, resulting in a larger effective capacity.

  Another object of the present invention is to provide an ultra-vacuum heat insulation tank using this dome end structure. This substantially obviates one or more of the problems resulting from the limitations and disadvantages of the related art.

  The following description also shows further advantages and features of the present invention. Those skilled in the art will be able to understand those skilled in the art by implementing the present invention. These and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

  In order to achieve these and other advantages, and in accordance with the purpose of the present invention, the dome end of the ultra-vacuum insulation tank for cryogenic liquefied gas is curved as illustrated and broadly described herein. A main body having a curved surface and a small dome end facing away from the main body. Specifically, the opposite small dome end is formed by a curved surface facing away from the curved surface of the inner container dome end. This opposite small dome end is connected to the body by an expansion neck. And this expansion neck is connected with the small dome end and main body of the opposite direction by the rounding shape, respectively. Further, a reinforcing structure is provided on the expansion neck, and a reinforcing plate is provided on the inner surface of the dome end of the inner container.

  In another aspect, an ultra-vacuum insulated tank for cryogenic liquefied gas includes a frame structure and a tank body, the tank body comprising an outer shell having a cylinder and two dome ends, a cylinder and two dome ends. An inner container, an ultra-vacuum thermal insulation layer between the outer shell and the inner container, and a support structure for connecting the outer shell and the inner container, the dome end of the inner container having a body with a curved surface; Including a small dome end in the opposite direction connected to the main body.

  According to the present invention, the composite support structure is provided only between the inner dome end and the outer dome end at both ends of the tank, and the radial support is not in direct contact with the outer shell. Thereby, the heat conduction area | region of the support body between an inner container and an outer shell decreases, and a better heat insulation performance is obtained. At the same time, since there is no radial support in the straight part, the ultra-vacuum insulation layer between the inner container and the outer shell can be thinned to 50 mm. This increases the effective capacity of the inner container and increases the loading efficiency.

  Further, the outer shell of the tank according to the present invention includes two dome ends, a cylinder, and a plurality of reinforcing rings. Unlike the related art, the reinforcing ring is provided outside the outer shell. This reduces the material used for the outer shell, making it lighter and lowering costs while meeting the preconditions that the inner diameter of the outer shell is the same and the dimensions of the reinforcing ring are the same. At the same time, the reinforcing ring also acts as a protector for the outer shell. A dome end of the inner container and a dome end of the outer shell (hereinafter referred to as an inner dome end and an outer dome end, respectively) are arranged in opposite directions, and a plurality of layers of heat insulating material are wound around the inner container. The inner container is connected to the outer shell by a composite support structure between the inner dome end and the outer dome end at both ends, which simultaneously withstands radial and longitudinal forces. Because the dome end of the inner container and the dome end of the outer shell are arranged in opposite directions, a composite support structure can be provided inside the inner dome end, thereby providing a space between the inner dome end and the outer dome end. The distance becomes smaller. Thus, the effective capacity of the inner container is increased while the outer shell dimensions remain the same.

  According to the present invention, it is possible to provide the ultra-vacuum internal support structure with a plurality of heat insulation layers having extremely high impact resistance and heat insulation performance. As a result, the impact resistance of the cryogenic liquefied gas storage or transport facility and the temperature fluctuations of the load satisfy the requirements for the cryogenic liquefied gas storage or transport. Furthermore, the ultra-vacuum layer between the inner container and the outer shell of the cryogenic tank can be made very thin to ultimately maximize the loading efficiency of the cryogenic liquefied gas.

  The foregoing general description of the invention and the following detailed description are exemplary and explanatory, and are intended to describe the claimed invention in greater detail.

  The accompanying drawings, which are incorporated in and form a part of this specification for a better understanding of the invention, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. .

  Preferred embodiments are described in detail below, and examples are shown in the accompanying drawings.

  FIG. 3 is a perspective view of an ultra-vacuum multilayer insulation tank for cryogenic liquefied gas according to the present invention. As shown in FIG. 3, the tank 100 includes a frame structure 101 and a tank body 102, which are welded together in a specific manner. In the case of a tank car, the frame structure 101 refers to a structure that fixes the tank main body 102 to the chassis of the car. In the case of a tank container, the frame structure 101 refers to a structure that fixes the tank main body 102 to a predetermined location of the container. Point to. In addition, a number of reinforcing rings 103 are provided on the outer surface of the tank.

  FIG. 4 is a schematic vertical sectional view of the tank shown in FIG. Referring to FIG. 4, the tank body 102 includes an outer shell 110 and an inner container 120, and the outer shell 110 seals the two ends of the cylinder 111 and the cylinder 111 with a first dome end 112 and a second dome end 112. The inner container 120 disposed inside the outer shell 110 includes the first dome end 122 and the second dome end 123 that respectively seal the two ends of the cylinder 121. Including. An ultra-vacuum heat insulating layer 104 is formed between the outer shell 110 and the inner container 120, and a plurality of layers of heat insulating material 105 are wound around the outer surface of the inner container 120 in the ultra-vacuum heat insulating layer 104.

  Referring to FIGS. 4 and 5, FIG. 5 is a perspective sectional view of the first dome end of the tank shown in FIG. 3. Specifically, the first dome end 122 of the inner container 120 has a first main body 1221 and a first reverse direction formed in a recessed shape from the center of the first main body 1221 into the inner container 120. With the small dome end 1222 (ie, the curved surface of the first opposite small dome end 1222 results in the opposite of the curved surface of the dome end 112 on the corresponding side of the outer shell 110), the first And a first expansion neck 1223 that is welded between the opposite small dome end 1222 and the first body 1221 to form a rounded structure, thereby reducing the internal stress of the inner container 120. In addition, a reinforcing plate 1224 can be further provided inside the dome end 122 of the inner container 120 in order to improve impact resistance. Similarly, referring to FIGS. 4 and 6, the second dome end 123 of the inner container 120 is formed into a second body 1231 and a recessed shape from the center of the second body 1231 into the inner container 120. Second opposite small dome end 1232 (ie, the curved surface of the second opposite small dome end 1232 results in the curved surface of the dome end 113 on the corresponding side of the outer shell 110). A second extension that is welded between the second opposite small dome end 1232 and the second body 1231 to form a rounded structure, thereby reducing the internal stress of the inner container 120. And a neck 1233. In addition, a reinforcing plate 1234 can be further provided on the inner side of the dome end 123 of the inner container 120 in order to improve impact resistance.

  The first dome end 112 of the outer shell 110 includes a main body 1121, a reinforcing plate 1122 formed at the center of the main body 1121, and a reinforcing tube 1123 connected to the reinforcing plate 1122 to ensure sufficient strength. In addition. The reinforcing pipe 1123 is provided with a reinforcing plate 1124 that increases the strength of the structure. In order to increase the strength of the first dome end 112, it is preferable to provide a reinforcing plate 1126 inside the first dome end 112. The second dome end 113 of the outer shell 110 is formed at the center of the main body 1131, the support tube 1132 attached from the inside to the center of the main body 1131, and the support tube 1132 to satisfy the assembly requirements. A reinforcing plate 1133 connected to the reinforcing plate 1133 and a reinforcing tube 1134 connected to the reinforcing plate 1133 and surrounding the support tube 1132 (the reinforcing tube 1134 is provided with a reinforcing plate 1135 for increasing the strength of the structure), 2 and the reinforcing plate 1136 provided inside the dome end 113. With these, the present invention can fully utilize the distance between the dome end of the outer shell and the dome end of the inner container to arrange the composite support structure.

  Referring to FIG. 4, the composite support structure includes a radial support structure and a longitudinal support structure separately. The radial support structure includes a first radial support structure 210 that cooperates with the first dome end 122 of the inner container 120 and a second radius that cooperates with the second dome end 123 of the inner container 120. Directional support structure 220. The first / second radial support structure 210/220 includes an inner fixation ring 2101/2201, an outer fixation ring 2102/2202, and a first / second radial support plate 2103/2203, Includes each separately. The inner fixation ring 2101/2201 and the outer fixation ring 2102/2202 are fixed in place inside the expansion neck 1223/1233 or inside the small dome end 1222/1232 in the opposite direction. The radial support plate 2103/2203 is fixed between the inner fixing ring 2101/2201 and the outer fixing ring 2102/2202, and cooperates closely with the dissimilar joint pipe 1223/1233 or the opposite dome end 1222/1232. . Clearly, the dome end of the inner container has a rounded structure, so that the loneliness gradually decreases from the expansion neck to the small dome end in the opposite direction. That is, the contact gap between the radial support plate and the dome end is self-adjusted. Therefore, when transitioning from a normal temperature state to a cryogenic state, the inner container 120 is affected by thermal expansion and low temperature shrinkage, but the first and second radial support plates are opposite small dome ends or extensions. It can remain tightly connected to the neck and avoid gaps. More importantly, since the radial support is provided directly on the dome end of the inner container, the ultra-vacuum insulation layer between the inner container and the outer shell can be thinned to 50 mm, which The effective capacity of the container is further increased.

  In addition, a longitudinal support structure 230 is provided between the first dome end 112 of the outer shell and the first dome end 122 of the inner container and penetrates the first radial support plate 2103. . The longitudinal support structure 230 is attached to the reinforcing plate 1122 of the outer shell 110, and is attached to the center of a support tube 2301 provided with a spacing blow-up 2302 inside and a small dome end 1222 in the opposite direction, A support shaft 2303 extending to the support tube 2301, a fixed component 2304 provided at an end of the support shaft 2303, a first filling block 2305 fixed between the fixed component 2304 and the blow-up 2302, and a small reverse direction And a second filling block 2306 secured between the dome end 2222 and the blowup 2302 of the support tube. The reinforcing tube 1123 and its reinforcing plate 1124 surround the support tube 2301 in order to strengthen the structure of the support tube 2301. As a result, the leftward and rightward longitudinal forces generated by the inner container 120 and the load during movement of the tank 100 push the second and first filling blocks, respectively, through the support tube. To the outer shell. A first finite element structural analysis and temperature analysis software is used to systematically design an internal support structure that maximizes load capacity while meeting heat leak and stress requirements, and is provided with a longitudinal support For the dome end spacing, an internal support structure compatible with the ultra-vacuum multilayer insulation structure can be obtained simply by satisfying the assembly requirements. In the present invention, the distance between the dome end of the inner container and the dome end of the outer shell at which the longitudinal force is transmitted at the end where the longitudinal support structure is provided is the distance of the pipe delivering liquid or gas. It depends on the liquid sealing and the spacing required to compensate for the effects of thermal expansion and cold shrinkage, for example, this spacing can be around 300 mm. In addition, a reinforcing structure can be provided on the support tube in order to increase the strength of the support tube.

  The first radial support structure 210, together with the second radial support structure 220, withstands the radial forces generated by the inner container 120 and the load. The outer peripheral portions of the support plates 2103 and 2203 are in contact with the dome ends 122 and 123 at portions extending into the inner container 120. This is advantageous with respect to placing a longitudinal support and reducing heat leakage due to the longitudinal support. The inner peripheral portions of the support plates 2103 and 2203 are connected to support tubes 2301 and 1132 attached to the dome ends 112 and 113 of the outer shell 110. In this way, the radial force is balanced and the reliability of the support structure is improved. At the same time, good heat insulation performance can be obtained. This is because the longitudinal heat transfer surface between the inner container and the outer shell is only the stress surface of the inner support structure, and heat is transferred by radiation to other parts of the inner container. This successfully overcomes the problem of heat leakage of the longitudinal support in the related art. Furthermore, since the distance between the inner dome end and the outer dome end is small, the loading rate is also increased. The support plate of the present invention is formed of a suitable glass fiber plastic material. By performing finite element analysis and experimental verification, the gap between the inner ring and the outer ring can be self-adjusted so that it hardly changes even when the normal temperature state is changed to the cryogenic state. This increases the impact resistance of the structure in the radial direction and is advantageous for assembly and clearance control at room temperature.

  In addition, the present invention makes full use of the characteristic of glass fiber plastic material that the ratio of compressive strength to thermal conductivity coefficient is higher than contact thermal resistance, the ability to withstand the radial force of the support structure and reduce heat leakage To increase. This solves a serious problem in the related art that the gap is enlarged at a low temperature and the impact resistance is lowered. The length of the glass fiber plastic filling block in the longitudinal direction is increased by the length of the dome end of the inner container extending into the inner container, thereby reducing the heat leakage of the longitudinal support and the longitudinal direction. This solves the problem in the related art that it is impossible to suppress heat leakage by the support structure. At the same time, it ensures the maximum capacity to accommodate the liquid within the limits of overall dimensions and resolves the contradiction between internal stress and thermal insulation.

  The tank of the present invention is very easy to assemble. First, the second dome end 113 is welded to the cylinder 111 to form a coupling portion. Next, the first dome end 122, the second dome end 123, and the cylinder 121 are welded together to form the inner container 120. Next, multiple layers of heat insulating material are wrapped around the outer surface of the inner container 120. In the assembly, first, the second radial support plate 2203 and the fixing ring 2201 inside thereof are arranged in the inner container 120, and the outer fixing ring 2202 is arranged in the inner peripheral portion of the outer fixing ring 2202. Is strongly pressed with a special tool, and the outer fixing ring 2202 is welded to the second expansion neck 1233 of the inner container 120 in a T-joint shape. This conveniently allows the outer shell coupling portion to be attached and the second radial support plate 2203 to be encapsulated according to the horizontal assembly process tube guide. Next, the first radial support plate 2103 and the inner fixing ring 2101 are arranged in the inner container 120, and the outer fixing ring 2102 is arranged in the inner peripheral portion of the outer fixing ring 2102. The outer fixing ring 2102 is welded to the first extension neck 1223 in a T-joint shape, the second filling block 2306 is attached to the support shaft 2303, and the first dome end 122 of the outer shell 110 is attached. The first radial support plate 2103 is sealed and the first dome end 112 is welded to the joint portion of the outer shell. In the subsequent step, the first filling block 2305 is disposed in the support tube 2301, and fixed to the support shaft 2303 by the fixing component 2304 to press the first filling block 2305 and the second filling block 2306, and the fixing component 2304. Are welded to the support shaft 2303 to achieve assembly of the composite support structure. Finally, the first sealing plate 1125 is welded to the first reinforcing plate 1122 in a lap joint shape, and the second reinforcing plate 1133 is welded to the second sealing plate 1137 in a lap joint shape. This forms a tank. Ultra vacuum pumping is performed to form the ultra vacuum heat insulating layer 104 between the outer shell 110 and the inner container 120. Next, the reinforcing ring 103 of the outer shell 110 is welded to the outer surface of the outer shell 110.

  It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention. Thus, it is intended that the present invention include modifications and variations of the present invention provided they come within the scope of the appended claims and their equivalents.

It is a schematic sectional drawing of the tank for cryogenic liquefied gas by related technology. 1 is a schematic view of an impact resistant support structure applied to a cryogenic container according to the related art. It is a perspective view of the ultra vacuum multilayer insulation tank for cryogenic liquefied gas by this device. FIG. 4 is a schematic vertical sectional view of the tank shown in FIG. 3. FIG. 4 is a perspective sectional view of a first dome end of the tank shown in FIG. 3. FIG. 4 is a perspective sectional view of a second dome end of the tank shown in FIG. 3.

Explanation of symbols

120 body (inner container)
122 Small dome end opposite (first dome end)
123 Reverse dome end (second dome end)
101 Frame structure 102 Tank body 110 Outer shell 111 Cylinder 112 First dome end 113 Second dome end

Claims (12)

  A dome end of an ultra-vacuum insulated tank for cryogenic liquefied gas comprising a main body having a curved surface and a small dome end facing away from the main body.   The dome end of an ultra-vacuum insulated tank for cryogenic liquefied gas according to claim 1, wherein the small dome end in the opposite direction is formed by a curved surface facing away from the curved surface of the main body.   The dome end of an ultra-vacuum insulated tank for cryogenic liquefied gas according to claim 2, wherein the opposite small dome end is connected to the body by an expansion neck.   The dome end of the ultra-vacuum insulation tank for cryogenic liquefied gas according to claim 3, wherein the expansion neck is connected to the small dome end in the opposite direction and the main body by a rounded shape.   The dome end of the ultra-vacuum insulation tank for cryogenic liquefied gas according to claim 4, wherein a reinforcement structure is provided on the expansion neck.   The dome end of an ultra-vacuum insulating tank for cryogenic liquefied gas according to claim 5, wherein a reinforcing plate is provided on the inner surface of the dome end of the inner container. Including a frame structure and a tank body,
The tank body is
An outer shell including a cylinder and two dome ends;
An inner container including a cylinder and two dome ends;
An ultra-vacuum insulation layer between the outer shell and the inner container;
A support structure connecting the outer shell and the inner container;
Including
The ultra-vacuum insulated tank for cryogenic liquefied gas, wherein the dome end of the inner container includes a main body having a curved surface and a small dome end facing in reverse direction.   The ultra-vacuum insulated tank for cryogenic liquefied gas according to claim 7, wherein the small dome end in the opposite direction is formed by a curved surface opposite to the curved surface of the main body.   9. The ultra-vacuum insulated tank for cryogenic liquefied gas according to claim 8, wherein the opposite small dome end is connected to the body by an expansion neck.   The ultra-vacuum insulated tank for cryogenic liquefied gas according to claim 9, wherein the expansion neck is connected to the main body and the opposite small dome end in a rounded shape.   The ultra-vacuum heat insulation tank for cryogenic liquefied gas according to claim 10, wherein a reinforcement structure is provided on the expansion neck.   The ultra-vacuum heat insulation tank for cryogenic liquefied gas according to claim 11, wherein a reinforcing plate is provided on an inner surface of a dome end of the inner container.

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