A cryogenic container with active insulation of dual liquid nitrogen tanks

Abstract

This invention belongs to the field of cryogenic storage technology for liquid hydrogen, liquid helium, etc., and discloses a cryogenic container with active insulation using dual liquid nitrogen tanks. The container includes an outer tank, a liquid nitrogen tank, a cold shield, and an inner tank disposed within the outer tank. The liquid nitrogen tank comprises a first liquid nitrogen tank and a second liquid nitrogen tank, which are respectively disposed at opposite ends within the outer tank and do not contact the outer tank. The cold shield is connected at both ends to the first and second liquid nitrogen tanks, respectively. The inner tank is disposed between the first liquid nitrogen tank, the second liquid nitrogen tank, and the cold shield, and does not contact these components. By configuring the first and second liquid nitrogen tanks, this application ensures that the end caps on both sides of the inner tank are within the favorable environment of liquid nitrogen temperature, guaranteeing long-term storage of the cryogenic medium. This also ensures that the inner tank is in a uniformly low-temperature environment with a low evaporation rate.

Description

Technical Field

[0001] This invention belongs to the field of cryogenic storage technology, including liquid hydrogen and liquid helium, and specifically relates to a cryogenic container with active insulation using dual liquid nitrogen tanks. Background Technology

[0002] Under standard conditions, hydrogen has a boiling point of -252.87℃, and helium has a boiling point of -268.9℃. Compared to gases at room temperature, cryogenic liquefied gases have the advantages of higher density and purity, which can effectively reduce transportation costs and improve the efficiency of transportation equipment. However, cryogenic liquefied gases have low latent heat of vaporization, making them highly volatile and thermally sensitive. For liquid hydrogen, rapid evaporation leads to lower safety of the entire storage tank, and hydrogen combustion is difficult to detect with the naked eye, easily causing safety risks. For liquid helium, liquid helium has a high value, and its evaporation should be minimized.

[0003] An existing patent (publication number: CN116164225A) discloses a liquid helium storage tank, comprising an outer shell, a cold shield, and an inner container arranged sequentially from the outside to the inside. The cold shield surrounds the inner container, and the outer shell surrounds the cold shield, forming a three-layer cylindrical horizontal structure. The liquid helium storage tank is divided into two temperature zones by the cold shield as a boundary and fulcrum. The inner container is supported by the cold shield and the outer shell, and the cold shield is supported by the outer shell. The hot end temperature of the inner container support structure can be reduced from 293K to 77K, thereby significantly reducing radiative heat transfer. This patent is a single liquid nitrogen tank solution, where a liquid nitrogen tank is placed on one side of the storage tank, while the other side is empty. This solution affects the overall temperature of the cold shield on the other side because the cold shield is cooled through liquid nitrogen pipelines, making it difficult for the temperature on the other side to reach the liquid nitrogen temperature range. In addition, the density of liquid nitrogen is much higher than that of liquid helium, and the overall center of gravity of the container shifts, posing a risk during storage tank transportation. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a cryogenic container with active insulation using dual liquid nitrogen tanks, comprising an outer tank, a liquid nitrogen tank, a cold shield, and an inner tank disposed within the outer tank. The liquid nitrogen tank includes a first liquid nitrogen tank and a second liquid nitrogen tank, which are respectively disposed at opposite ends within the outer tank and do not contact the outer tank. The two ends of the cold shield are respectively connected to the first liquid nitrogen tank and the second liquid nitrogen tank. The inner tank is disposed between the first liquid nitrogen tank, the second liquid nitrogen tank, and the cold shield, and the inner tank does not contact the first liquid nitrogen tank, the second liquid nitrogen tank, or the cold shield.

[0005] Furthermore, it also includes a connecting pipe located between the outer tank and the cold shield, with one end of the connecting pipe connected to the first liquid nitrogen tank and the other end connected to the second liquid nitrogen tank.

[0006] Furthermore, it also includes a cold screen pipeline, which is wound around the outer wall of the cold screen. One end of the cold screen pipeline is connected to the liquid nitrogen tank, and the other end of the cold screen pipeline passes through the outer tank and is connected to the air.

[0007] Furthermore, the cold screen pipeline includes a first cold screen pipeline and a second cold screen pipeline. The first cold screen pipeline is wound around the outer wall of the cold screen. One end of the first cold screen pipeline is connected to the first liquid nitrogen tank, and the other end passes through the outer tank and is connected to the air. The second cold screen pipeline is wound around the outer wall of the cold screen. One end of the second cold screen pipeline is connected to the second liquid nitrogen tank, and the other end passes through the outer tank and is connected to the air.

[0008] Furthermore, it also includes liquid nitrogen tank support structures, several of which are disposed between the outer tank and the liquid nitrogen tank.

[0009] Furthermore, the liquid nitrogen tank support structure includes a fixing ring, a support tube, and a sliding ball bearing. The fixing ring includes a first fixing ring and a second fixing ring. The first fixing ring is disposed on the inner wall of the outer tank, and the second fixing ring is disposed on the outer wall of the liquid nitrogen tank opposite to the first fixing ring. One end of the support tube is disposed inside the first fixing ring, and the other end is disposed inside the second fixing ring. The sliding ball bearing is disposed between the fixing ring and the support tube.

[0010] Furthermore, it also includes an inner tank support structure, with two inner tank support structures respectively disposed at both ends of the inner tank, and the two inner tank support structures respectively connected to the first liquid nitrogen tank and the second liquid nitrogen tank.

[0011] Furthermore, the inner tank support structure includes a fixed pull strap, a connecting rod, an annular support, an inner tank support tube, balls, a ball sleeve, and a diagonal tie rod. The two ends of the multiple fixed pull straps are respectively connected to the two ends of the liquid nitrogen tank. The outer ring of the annular support is connected to the fixed pull strap through the connecting rod. The inner ring of the annular support is connected to the ball sleeve through the diagonal tie rod. One end of the inner tank support tube is connected to the outer wall of the inner tank, and the other end of the inner tank support tube is inserted into the ball sleeve. The balls are disposed between the ball sleeve and the inner tank support tube.

[0012] Furthermore, the material of the cold screen is aluminum or copper.

[0013] Furthermore, the support tube is made of epoxy resin reinforced fiberglass.

[0014] Compared with the prior art, the beneficial effects of this application are as follows:

[0015] 1. By setting up a first liquid nitrogen tank and a second liquid nitrogen tank, this application can ensure that the end cap areas on both sides of the inner tank are in the favorable environment of liquid nitrogen temperature, thus ensuring the long-term storage of the low-temperature medium and keeping the inner tank in a uniform low-temperature environment with a low evaporation rate.

[0016] 2. This application winds the outer cylinder of the cold screen by setting up a first cold screen pipeline and a second cold screen pipeline, so that the liquid nitrogen in the first cold screen pipeline and the second cold screen pipeline can cool the cold screen, making the temperature distribution of the cold screen more uniform.

[0017] 3. This application sets up sliding balls to make point contact between the fixed ring and the support tube, and the balls make point contact between the inner tank support tube and the ball sleeve, avoiding surface contact, reducing the contact area for heat transfer, greatly increasing the overall thermal resistance, and reducing the evaporation rate of the storage tank.

[0018] 4. In this application, the first liquid nitrogen tank and the second liquid nitrogen tank are located at both ends of the inner tank. Since the density of liquid nitrogen is greater than that of liquid hydrogen and liquid helium, the structure of the liquid nitrogen tanks on both sides makes the center of gravity of the container more central, and it is less likely to overturn or collapse during transportation and hoisting, thus improving the safety of the storage tank.

[0019] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic diagram of a cryogenic container in an embodiment of the present invention is shown;

[0022] Figure 2 A schematic diagram of the liquid nitrogen tank support structure in an embodiment of the present invention is shown;

[0023] Figure 3 A top view of the liquid nitrogen tank support structure in an embodiment of the present invention is shown;

[0024] Figure 4 A schematic diagram of the inner tank support structure in an embodiment of the present invention is shown;

[0025] Figure 5 A left view of the inner tank support structure in an embodiment of the present invention is shown;

[0026] Figure 6 A schematic diagram of the first cold shield pipeline and the second cold shield pipeline in an embodiment of the present invention is shown.

[0027] In the diagram, 1. Outer tank; 2. Liquid nitrogen tank; 21. First liquid nitrogen tank; 22. Second liquid nitrogen tank; 23. Connecting pipeline; 3. Cold shield; 4. Inner tank; 5. Cold shield pipeline; 51. First cold shield pipeline; 52. Second cold shield pipeline; 6. Liquid nitrogen tank support structure; 61. First fixing ring; 62. Second fixing ring; 63. Support pipe; 64. Sliding ball; 7. Inner tank support structure; 71. Fixing strap; 72. Connecting rod; 73. Circular support; 74. Inner tank support pipe; 75. Ball; 76. Ball sleeve; 77. Diagonal tie rod. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] like Figure 1 As shown, a cryogenic container with active insulation using dual liquid nitrogen tanks includes an outer tank 1, a liquid nitrogen tank 2, a cold shield 3, and an inner tank 4 disposed within the outer tank 1. The liquid nitrogen tank 2 includes a first liquid nitrogen tank 21 and a second liquid nitrogen tank 22, which are respectively disposed at both ends within the outer tank 1 and do not contact the outer tank 1. The two ends of the cold shield 3 are respectively connected to the first liquid nitrogen tank 21 and the second liquid nitrogen tank 22. The inner tank 4 is disposed between the first liquid nitrogen tank 21, the second liquid nitrogen tank 22, and the cold shield 3, and the inner tank 4 does not contact the first liquid nitrogen tank 21, the second liquid nitrogen tank 22, or the cold shield 3.

[0030] The cold screen 3 is cylindrical, and its two ends are connected to the first liquid nitrogen tank 21 and the second liquid nitrogen tank 22, respectively. Therefore, the cold screen 3, the first liquid nitrogen tank 21 and the second liquid nitrogen tank 22 form a sealed low-temperature space. The space between the cold screen 3, the first liquid nitrogen tank 21 and the second liquid nitrogen tank 22 and the outer tank 1 is filled with vacuum to form a first vacuum layer. The space between the cold screen 3, the first liquid nitrogen tank 21 and the second liquid nitrogen tank 22 and the inner tank 4 is filled with vacuum to form a second vacuum layer. The first vacuum layer and the second vacuum layer are filled with high-vacuum insulation material to further ensure the overall low-temperature performance of the storage tank.

[0031] The outer tank 1 is in the external environment, and the inner tank 4 and liquid nitrogen tank 2 are inside the outer tank 1. The inner tank 4 and liquid nitrogen tank 2 are made of austenitic stainless steel.

[0032] The inner tank 4 is cylindrical in the middle and spherical at both ends. The spherical ends are also called the inner tank 4 heads. The inner tank 4 heads at both ends are placed in the first liquid nitrogen tank 21 and the second liquid nitrogen tank 22 respectively, ensuring that the areas of the inner tank 4 head on both sides are in the favorable environment of the liquid nitrogen temperature zone. This ensures that the low-temperature storage medium can be stored in the tank for a long time, and keeps the inner tank 4 in a low-temperature environment with a uniform temperature and a low evaporation rate.

[0033] The cryogenic container with active insulation of dual liquid nitrogen tanks also includes a connecting pipe 23, which is located between the outer tank 1 and the cold shield 3. One end of the connecting pipe 23 is connected to the first liquid nitrogen tank 21, and the other end is connected to the second liquid nitrogen tank 22.

[0034] The connecting pipe 23 is located in the first vacuum layer, and its two ends are connected to the first liquid nitrogen tank 21 and the second liquid nitrogen tank 22 respectively. The purpose is to keep the liquid nitrogen in the first liquid nitrogen tank 21 and the second liquid nitrogen tank 22 the same, so as to keep the balance during transportation.

[0035] The cryogenic container with active insulation of dual liquid nitrogen tanks also includes a cold shield pipe 5, which is wrapped around the outer wall of the cold shield 3. One end of the cold shield pipe 5 is connected to the liquid nitrogen tank 2, and the other end of the cold shield pipe 5 passes through the outer tank 1 and is connected to the air.

[0036] The cold screen pipeline 5 includes a first cold screen pipeline 51 and a second cold screen pipeline 52. The first cold screen pipeline 51 is wrapped around the outer wall of the cold screen 3. One end of the first cold screen pipeline 51 is connected to the first liquid nitrogen tank 21, and the other end passes through the outer tank 1 and is connected to the air. The second cold screen pipeline 52 is wrapped around the outer wall of the cold screen 3. One end of the second cold screen pipeline 52 is connected to the second liquid nitrogen tank 22, and the other end passes through the outer tank 1 and is connected to the air.

[0037] The first cold shield pipe 51 and the second cold shield pipe 52 can be wound around the outer cylindrical surface of the cold shield 3, or the outer cylindrical surface of the cold shield 3 can be divided into two sections, with the second cold shield pipe 52 wound around the outer cylindrical surface from 0 to 180 degrees and the first cold shield pipe 51 wound around the outer cylindrical surface from 180 degrees to 360 degrees. One end of the first cold shield pipe 51 is connected to the first liquid nitrogen tank 21, so that the cooling medium in the first cold shield pipe 51 is liquid nitrogen. One end of the second cold shield pipe 52 is connected to the second liquid nitrogen tank 22, so that the cooling medium in the first cold shield pipe 51 is also liquid nitrogen. The connection between the cold shield pipe 3 and the liquid nitrogen tank 2, and the winding around the outer cylinder of the cold shield 3, provide a low-temperature protective shell for the inner tank 4.

[0038] like Figure 2 and 3As shown, the cryogenic container with active insulation of dual liquid nitrogen tanks also includes liquid nitrogen tank support structures 6, with several of the liquid nitrogen tank support structures 6 disposed between the outer tank 1 and the liquid nitrogen tank 2. The liquid nitrogen tank 2 is fixed to the outer tank 1 by the liquid nitrogen tank support structures 6, ensuring that the liquid nitrogen tank 2 does not come into contact with the outer tank 1, thus preventing heat transfer and the evaporation of liquid hydrogen and liquid helium stored in the inner tank 4.

[0039] The liquid nitrogen tank support structure 6 includes a fixing ring, a support tube 63, and a sliding ball bearing 64. The fixing ring includes a first fixing ring 61 and a second fixing ring 62. The first fixing ring 61 is disposed on the inner wall of the outer tank 1, and the second fixing ring 62 is disposed on the outer wall of the liquid nitrogen tank 2 opposite to the first fixing ring 61. One end of the support tube 63 is disposed inside the first fixing ring 61, and the other end is disposed inside the second fixing ring 62. The sliding ball bearing 64 is disposed between the fixing ring and the support tube 63.

[0040] The liquid nitrogen tank 2 requires several liquid nitrogen tank support structures 6. Typically, the first liquid nitrogen tank 21 and the second liquid nitrogen tank 22 are each supported by four liquid nitrogen tank support structures 6 of the same specifications. They can be evenly distributed along the circumference or at different angles.

[0041] The inner tank 4 typically stores liquid helium and liquid hydrogen, while the liquid nitrogen tank 2 stores liquid nitrogen. Because the density of liquid nitrogen is much greater than that of liquid hydrogen and liquid helium, this completely fixed structure also increases the overall strength of the storage tank, ensuring that the storage tank will not experience central instability during transportation.

[0042] The sliding ball bearing 64 makes point contact between the fixed ring and the support tube 63, avoiding surface contact, reducing the contact area for heat transfer, greatly increasing the overall thermal resistance, and reducing the evaporation rate of the storage tank.

[0043] like Figure 4 and 5 As shown, the cryogenic container with dual liquid nitrogen tanks and active insulation further includes an inner tank support structure 7. Two inner tank support structures 7 are respectively disposed at both ends of the inner tank 4, and are connected to the first liquid nitrogen tank 21 and the second liquid nitrogen tank 22, respectively. The inner tank 4 is fixed to the liquid nitrogen tank 2 via the inner tank support structures 7, preventing the inner tank 4 from contacting the outer tank 1 and preventing heat transfer that could cause the liquid hydrogen and liquid helium stored in the inner tank 4 to evaporate.

[0044] The inner tank support structure 7 includes fixed straps 71, connecting rods 72, annular supports 73, an inner tank support tube 74, ball bearings 75, ball bearing sleeves 76, and diagonal tie rods 77. The two ends of the multiple fixed straps 71 are connected to the two ends of the liquid nitrogen tank 2, respectively. The outer ring of the annular support 73 is connected to the fixed straps 71 via the connecting rods 72, and the inner ring of the annular support 73 is connected to the ball bearing sleeves 76 via the diagonal tie rods 77. One end of the inner tank support tube 74 is connected to the outer wall of the inner tank 4, and the other end of the inner tank support tube 74 is inserted into the ball bearing sleeves 76. The ball bearings 75 are positioned between the ball bearing sleeves 76 and the inner tank support tube 74. The ball bearings 75 ensure point contact between the inner tank support tube 74 and the ball bearing sleeves 76, avoiding surface contact, reducing the contact area for heat transfer, significantly increasing the overall thermal resistance, and reducing the evaporation rate of the storage tank.

[0045] The inner tank support structure 7 is made of metal. The metal fixing strap 71 connects the inner tank 4 and the liquid nitrogen tank 2, so that the temperature difference between the two sides is lower than that of the direct connection of the outer tank 1, which reduces the heat loss by 2 / 3 and improves the thermal insulation performance of the storage tank.

[0046] The cold screen 3 is made of a metal material with high thermal conductivity, such as aluminum or copper.

[0047] The support tube 63 is made of epoxy resin reinforced fiberglass.

[0048] like Figure 6 As shown, because the cryogenic container is equipped with a first liquid nitrogen tank 21 and a second liquid nitrogen tank 22, there is no need to consider the influence of the cold shield 3 on the temperature environment of the inner tank 4 head. The inner tank 4 can be fully enclosed by winding the cold shield pipe 5 around the body of the cold shield 3. The first cold shield pipe 51 is connected to the first liquid nitrogen tank 21, and the second cold shield pipe 52 is connected to the second liquid nitrogen tank 22. They are wound around the cold shield 3 respectively, and their boundary line is 0°-180°. The first cold shield pipe 51 and the second cold shield pipe 52 are only wound on one side. When the liquid nitrogen in the liquid nitrogen tank 2 vaporizes and is pressurized, the liquid nitrogen rises along the cold shield pipe 5, and the body of the cold shield 3 will reach the liquid nitrogen temperature zone. Then, together with the liquid nitrogen storage tank, it will act around the inner tank 4 to provide the inner tank 4 with the ambient temperature of the liquid nitrogen temperature zone, reduce the cold leakage of the inner tank 4, and improve the cold insulation effect of the storage tank.

[0049] Although the present invention 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 of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cryogenic container with active insulation of dual liquid nitrogen tanks, characterized in that: The system includes an outer tank (1), a liquid nitrogen tank (2), a cold shield (3), and an inner tank (4) disposed inside the outer tank (1). The liquid nitrogen tank (2) includes a first liquid nitrogen tank (21) and a second liquid nitrogen tank (22). The first liquid nitrogen tank (21) and the second liquid nitrogen tank (22) are respectively disposed at both ends inside the outer tank (1) and do not contact the outer tank (1). The two ends of the cold shield (3) are respectively connected to the first liquid nitrogen tank (21) and the second liquid nitrogen tank (22). The inner tank (4) is disposed between the first liquid nitrogen tank (21), the second liquid nitrogen tank (22), and the cold shield (3), and the inner tank (4) does not contact the first liquid nitrogen tank (21), the second liquid nitrogen tank (22), and the cold shield (3).

2. The cryogenic container with active insulation for dual liquid nitrogen tanks according to claim 1, characterized in that: It also includes a connecting pipe (23), which is located between the outer tank (1) and the cold shield (3). One end of the connecting pipe (23) is connected to the first liquid nitrogen tank (21), and the other end is connected to the second liquid nitrogen tank (22).

3. The cryogenic container with active insulation for dual liquid nitrogen tanks according to claim 1, characterized in that: It also includes a cold screen pipeline (5), which is wrapped around the outer wall of the cold screen (3). One end of the cold screen pipeline (5) is connected to the liquid nitrogen tank (2), and the other end of the cold screen pipeline (5) passes through the outer tank (1) and is connected to the air.

4. The cryogenic container with active insulation for dual liquid nitrogen tanks according to claim 3, characterized in that: The cold screen pipeline (5) includes a first cold screen pipeline (51) and a second cold screen pipeline (52). The first cold screen pipeline (51) is wrapped around the outer wall of the cold screen (3). One end of the first cold screen pipeline (51) is connected to the first liquid nitrogen tank (21), and the other end passes through the outer tank (1) and is connected to the air. The second cold screen pipeline (52) is wrapped around the outer wall of the cold screen (3). One end of the second cold screen pipeline (52) is connected to the second liquid nitrogen tank (22), and the other end passes through the outer tank (1) and is connected to the air.

5. The cryogenic container with active insulation for dual liquid nitrogen tanks according to claim 1, characterized in that: It also includes liquid nitrogen tank support structures (6), and several of the liquid nitrogen tank support structures (6) are disposed between the outer tank (1) and the liquid nitrogen tank (2).

6. The cryogenic container with active insulation for dual liquid nitrogen tanks according to claim 5, characterized in that: The liquid nitrogen tank support structure (6) includes a fixing ring, a support tube (63), and a sliding ball (64). The fixing ring includes a first fixing ring (61) and a second fixing ring (62). The first fixing ring (61) is disposed on the inner wall of the outer tank (1), and the second fixing ring (62) is disposed on the outer wall of the liquid nitrogen tank (2) opposite to the first fixing ring (61). One end of the support tube (63) is disposed inside the first fixing ring (61), and the other end is disposed inside the second fixing ring (62). The sliding ball (64) is disposed between the fixing ring and the support tube (63).

7. The cryogenic container with active insulation for dual liquid nitrogen tanks according to claim 1, characterized in that: It also includes an inner tank support structure (7), with two inner tank support structures (7) respectively located at both ends of the inner tank (4), and the two inner tank support structures (7) respectively connected to the first liquid nitrogen tank (21) and the second liquid nitrogen tank (22).

8. The cryogenic container with active insulation for dual liquid nitrogen tanks according to claim 7, characterized in that: The inner tank support structure (7) includes a fixed pull strap (71), a connecting rod (72), an annular support (73), an inner tank support tube (74), a ball bearing (75), a ball bearing sleeve (76), and a diagonal tie rod (77). The two ends of the multiple fixed pull straps (71) are respectively connected to the two ends of the liquid nitrogen tank (2). The outer ring of the annular support (73) is connected to the fixed pull strap (71) through the connecting rod (72). The inner ring of the annular support (73) is connected to the ball bearing sleeve (76) through the diagonal tie rod (77). One end of the inner tank support tube (74) is connected to the outer wall of the inner tank (4). The other end of the inner tank support tube (74) is inserted into the ball bearing sleeve (76). The ball bearing (75) is disposed between the ball bearing sleeve (76) and the inner tank support tube (74).

9. The cryogenic container with active insulation for dual liquid nitrogen tanks according to claim 1, characterized in that: The material of the cold screen (3) is aluminum or copper.

10. The cryogenic container with active insulation for dual liquid nitrogen tanks according to claim 6, characterized in that: The support tube (63) is made of epoxy resin reinforced fiberglass.

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