JP2024016651A - Multiple shell structure body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure in which a flow of exhaust emission is hardly obstructed by a laminated heat insulation material when forcibly exhausting air between a first shell and a second shell from an exhaust port which is arranged at the second shell, in a multiple shell structure body having the first shell, the second shell surrounding the first shell, and the laminated heat insulation material arranged between the first shell and the second shell.

SOLUTION: A multiple shell structure body comprises a first shell, a laminated heat insulation material surrounding the first shell, a second shell surrounding the laminated heat insulation material and having an exhaust port, and an exhaust port cover arranged at the exhaust port in an intermediate chamber between the first shell and the second shell. The exhaust port cover has a lid body having a main face facing a surface of the laminated heat insulation material around the exhaust port cover, and a body having a communication port which connects the lid body and the exhaust port, and makes the intermediate chamber and the exhaust port communicate with each other, and whose opening axial direction is substantially parallel with the main face of the lid body.

SELECTED DRAWING: Figure 4

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present disclosure relates to multi-shell structures with vacuum insulation layers.

Conventionally, multi-shell tanks have been used as containers for storing cryogenic liquefied gas. Some multi-shell tanks have an inner tank containing liquefied gas and an outer tank surrounding the inner tank, with a vacuum insulation layer between the inner and outer tanks reduced to a near-vacuum state. Examples of such multi-shell tanks include liquefied gas storage tanks installed on the ground, cargo handling tanks and fuel tanks mounted on ships, and liquefied gas transport tanks included in tank containers. Patent Document 1 discloses a multi-shell tank as a liquefied gas transport tank.

The multi-shell tank (transport container) described in Patent Document 1 includes an inner tank (inner container) that accommodates liquefied gas, a heat shield surrounding the inner tank, and a refrigerant tank that accommodates a refrigerant to be supplied to the heat shield. It includes an inner tank, a heat shield, and an outer tank (outer container) surrounding the refrigerant tank. The outer surface of the inner tank is covered with Multilayer Insulation (MLI), which consists of multiple foil-like elements. The intermediate chamber between the inner tank and the outer tank is a vacuum insulation layer whose pressure is reduced to a state close to vacuum.

JP 2019-515218 Publication

Conventionally, in order to create a vacuum between the inner and outer tanks of a multi-shell tank, a vacuum pump is connected to an exhaust port disposed in the outer tank, and the vacuum pump is operated to forcibly exhaust the space between the inner and outer tanks. However, in cases where the outer surface of the inner tank is covered with a laminated heat insulating material as in Patent Document 1, the laminated heat insulating material peels off or lifts from the inner tank due to the suction force generated at the exhaust port and obstructs the flow of exhaust gas. However, it sometimes took more time than expected to evacuate the space between the inner and outer tanks to the desired degree of vacuum.

The present disclosure has been made in view of the above circumstances, and includes a first shell, a second shell surrounding the first shell, and a laminated heat insulating material disposed between the first shell and the second shell. To provide a multi-shell structure in which the flow of exhaust gas is less likely to be obstructed by a laminated heat insulating material when a space between a first shell and a second shell is forcibly exhausted from an exhaust port arranged in the second shell. It is in.

In order to solve the above problems, a multi-shell structure according to one aspect of the present disclosure,
The first shell,
a laminated insulation material surrounding the first shell;
a second shell surrounding the laminated insulation material and having an exhaust port;
an exhaust port cover disposed over the exhaust port in an intermediate chamber between the first shell and the second shell;
The exhaust port cover connects a lid body having a main surface facing the surface of the laminated heat insulating material surrounding the exhaust port cover, and the lid body and the exhaust port, and connects the intermediate chamber and the exhaust port. and a body having a communication port that communicates with the exhaust port and whose opening axis direction is substantially parallel to the main surface of the lid.

According to the present disclosure, in a multi-shell structure including a first shell, a second shell surrounding the first shell, and a laminated heat insulating material disposed between the first shell and the second shell, the second shell It is possible to provide a structure in which the flow of exhaust gas is less likely to be obstructed by the laminated heat insulating material when the space between the first shell and the second shell is forcibly exhausted from the exhaust port disposed in the exhaust port.

FIG. 1 is a diagram showing a schematic configuration of a tank container 1 including a multi-shell tank according to a first embodiment of the present disclosure. FIG. 2 is a longitudinal sectional view of a multi-shell tank. FIG. 3 is a sectional view of the outer shell around the exhaust port, showing the structure of the exhaust port cover. FIG. 4 is a sectional view of the area around the exhaust port of the outer shell showing the flow of exhaust gas in the exhaust port cover. FIG. 5 is a sectional view showing a schematic configuration of a vacuum multiplex tube according to a second embodiment of the present disclosure. FIG. 6 is a sectional view of the outer shell around the exhaust port showing the structure of the exhaust port cover.

A multi-shell structure according to the present disclosure includes a first shell and a second shell surrounding the first shell, a laminated insulation material is disposed between the first shell and the second shell, and the pressure is reduced to a state close to vacuum. It has a vacuum insulation layer. Below, a first embodiment in which such a multi-shell structure is applied to a multi-shell tank and a second embodiment in which such a multi-shell structure is applied to a vacuum multiple pipe 15 will be described.

[First embodiment]
The multi-shell structure according to the first embodiment is a multi-shell tank 11. FIG. 1 is a diagram showing a schematic configuration of a tank container 1 including a multi-shell structure according to a first embodiment of the present disclosure, and in this diagram, the inside of an outer shell 22 is shown transparently. A tank container 1 shown in FIG. 1 is used when transporting liquefied gas by ship or vehicle. Liquefied gases are liquids at extremely low temperatures, such as liquefied helium, liquefied hydrogen, and liquefied natural gas. Below, the configuration of the tank container 1 will be explained.

<Schematic configuration of tank container 1>
The tank container 1 includes a multi-shell tank 11 that is a multi-shell structure, and a frame 12 that supports the multi-shell tank 11. A substantially horizontal central axis C is defined in the multi-shell tank 11, and the direction in which this central axis C extends is referred to as the "axial direction X." The multi-shell tank 11 has a cylindrical shape with the central axis C as its axis, and the longitudinal direction of the multi-shell tank 11 is substantially parallel to the axial direction X. The frame body 12 has support parts arranged at both ends of the multi-shell tank 11 in the axial direction X. By supporting both ends of the multi-shell tank 11 in the longitudinal direction by the frame body 12, the multi-shell tank 11 is held by the frame body 12 so as not to be relatively movable.

The multi-shell tank 11 included in the tank container 1 has a heat insulating structure that keeps the stored liquefied gas at an extremely low temperature in order to suppress vaporization of the liquefied gas during transportation. The multi-shell tank 11 includes an inner shell 21, an outer shell 22, a heat shield 24, and a refrigerant tank 46.

The inner shell 21 is made of a metal such as SUS, and has a cylindrical body whose axis is centered around the central axis C, and end plates that close both ends of the body. Liquefied gas is contained in the inner shell 21 in a hermetically sealed state. The outer shell 22 covers the entire periphery of the inner shell 21. The outer shell 22 is made of a metal such as SS material or SUS, and has a cylindrical body whose axis is centered on the central axis C, and an end plate that closes both ends of the body. The outer shell 22 is larger than the inner shell 21 to accommodate the inner shell 21 therein, and the outer wall of the inner shell 21 and the inner wall of the outer shell 22 are spaced apart.

The inner shell 21 is supported by the outer shell 22 via a support shaft 30. The support shaft 30 is a shaft-shaped member that is arranged to overlap the central axis C and extends in the axial direction X. The support shaft 30 is coupled to both the inner shell 21 and the outer shell 22.

Both ends of the inner shell 21 in the axial direction X are supported by the outer shell 22 via a plurality of suspension rods 33 . The proximal end of each suspension rod 33 is connected to the longitudinal end of the inner shell 21 , and the distal end of each suspension rod 33 is connected to the outer shell 22 . The plurality of suspension rods 33 are arranged to extend radially around the central axis C. In this way, the support shaft 30 and the plurality of suspension rods 33 allow the inner shell 21 to be spaced apart from the inner wall of the outer shell 22 inside the outer shell 22, in other words, to float inside the outer shell 22. It is supported by the outer shell 22 in this state.

FIG. 2 is a longitudinal sectional view of the multi-shell tank 11. As shown in FIGS. 1 and 2, a hollow intermediate chamber 25 is formed between the inner shell 21 and the outer shell 22. The intermediate chamber 25 is in a state where the pressure is reduced to near vacuum (hereinafter referred to as a "vacuum state") in order to suppress convective heat transfer. Furthermore, a laminated heat insulating material 26 covering the inner shell 21 is arranged in the intermediate chamber 25 . The laminated heat insulating material 26 is called MLI (Multilayer Insulation), and is a heat insulating material composed of multiple layers of thin sheets. Although the configuration of the laminated heat insulating material 26 is not particularly limited, it is desirable that the laminated heat insulating material 26 has a heat insulating performance corresponding to the temperature of the liquefied gas contained in the inner shell 21. The laminated heat insulating material 26 is, for example, a lamination of a large number of aluminum vapor-deposited films with low emissivity and polyester nonwoven fabrics with low thermal conductivity that prevent the films from coming into contact with each other, thereby suppressing radiant heat transfer.

A heat shield 24 is arranged in the intermediate chamber 25 . The heat shield 24 absorbs a portion of the radiant heat from the outer shell 22 and blocks heat input to the inner shell 21. The heat shield 24 includes a shield plate 23 that covers the inner shell 21 covered with a laminated heat insulating material 26, and a cooling pipe 41 that is arranged on the surface of the shield plate 23 and through which a refrigerant 44 flows. The shield plate 23 is made of a metal panel material such as aluminum, and has a cylindrical shape with the central axis C as its axis. The longitudinal direction of the shield plate 23 is approximately parallel to the extending direction of the central axis C.

The cooling pipe 41 is arranged along the surface of the shield plate 23. A refrigerant 44 supplied from a refrigerant tank 46 flows through the cooling pipe 41, and the refrigerant 44 exchanges heat with the shield plate 23, thereby maintaining the surface temperature of the shield plate 23 at an extremely low temperature. The refrigerant tank 46 is disposed between the end of the inner shell 21 in the axial direction X and the outer shell 22, and the support shaft 30 penetrates the refrigerant tank 46 in the axial direction X. A refrigerant 44 is stored in the refrigerant tank 46 . The refrigerant 44 is, for example, a low-temperature liquid such as liquid nitrogen. The type of refrigerant 44 may be selected depending on the type of liquefied gas contained in the inner shell 21.

A laminated heat insulating material 27 covering the heat shield 24 is arranged in the intermediate chamber 25 . The laminated heat insulating material 27 may be of the same type as the laminated heat insulating material 26 covering the inner shell 21, or may be of a different type. Although the configuration of the laminated heat insulating material 27 is not particularly limited, it is desirable that the laminated heat insulating material 27 has a heat insulating performance corresponding to the temperature of the liquefied gas contained in the inner shell 21. In the multi-shell tank 11 including the laminated heat insulating material 27 covering the heat shield 24 in this manner, the laminated heat insulating material 26 covering the inner shell 21 may be omitted.

<Exhaust structure of intermediate chamber 25>
Here, the exhaust structure of the intermediate chamber 25 will be explained. As shown in FIG. 2, the outer shell 22 is provided with an exhaust port 63. Although the exhaust port 63 is shown at one location in FIG. 2, the exhaust port 63 may be provided at multiple locations on the outer shell 22. Although not particularly limited, in the example shown in FIG. 2, an exhaust pipe 64 that penetrates the outer shell 22 in the wall thickness direction is arranged in the outer shell 22, and the exhaust port 63 is formed by this exhaust pipe 64. There is. The direction perpendicular to the flow path cross section of the exhaust port 63 is defined as the "opening axis direction Y1" of the exhaust port 63. In this embodiment, the opening axis direction Y1 of the exhaust port 63 is substantially parallel to the extending direction of the tube axis of the exhaust pipe 64. One end of the exhaust pipe 64 is disposed in the intermediate chamber 25, and the other end of the exhaust pipe 64 is disposed outside the outer shell 22 and is closed by a valve 66 so as to be openable and closable. When evacuating the intermediate chamber 25, a vacuum pump 65 is connected to the exhaust pipe 64 via a valve 66 and piping, so that the intermediate chamber 25 and the vacuum pump 65 are communicated with each other.

An exhaust port cover 7 is disposed over the exhaust port 63 in the intermediate chamber 25 . More specifically, the exhaust port cover 7 is attached to the end of the exhaust pipe 64. FIG. 3 is a sectional view of the vicinity of the exhaust port 63 of the outer shell 22 showing the structure of the exhaust port cover 7. As shown in FIG. As shown in FIG. 3, an exhaust port cover 7 is disposed on the exhaust port 63 so as to cover the exhaust port 63. The exhaust port cover 7 has a body 71 and a lid body 72. In this embodiment, the exhaust port cover 7 and the exhaust pipe 64 are separate bodies, and the exhaust port cover 7 is attached to the exhaust pipe 64, but the exhaust port cover 7 is integrally provided at the tip of the exhaust pipe 64. Alternatively, the body 71 of the exhaust port cover 7 may be integrally formed at the tip of the exhaust pipe 64, and the lid body 72 may be attached thereto.

The main surface 72a of the lid 72 of the exhaust port cover 7 faces the surface of the laminated heat insulating material 27 around the exhaust port 63. Note that the laminated heat insulating material 27 around the exhaust port 63 includes at least a portion of the laminated heat insulating material 27 that exists in a region where the exhaust port 63 is extended in the opening axis direction Y1. The surface of the laminated heat insulating material 27 around the exhaust port cover 7 may be a curved surface instead of a flat surface, and the main surface 72a of the lid body 72 is also not limited to a flat surface. Therefore, although the main surface 72a of the lid 72 and the surface of the laminated heat insulating material 27 are opposed to each other, these surfaces are not limited to being parallel.

The body 71 connects the lid 72 and the exhaust port 63. The body 71 of the exhaust port cover 7 according to this embodiment has a cylindrical shape extending substantially parallel to the opening axis direction Y1 of the exhaust port 63. However, the aspect of the body 71 is not limited to this embodiment.

A plurality of communication ports 73 are opened in the body 71 of the exhaust port cover 7. The plurality of communication ports 73 are preferably arranged in a distributed manner in the circumferential direction in the body 71. Each communication port 73 communicates between the intermediate chamber 25 and the exhaust port 63. Further, when the direction perpendicular to the flow path cross section of the communication port 73 is defined as the "opening axis direction Y2" of the communication port 73, the opening axis direction Y2 of each communication port 73 is substantially parallel to the main surface 72a of the lid body 72. It is. Here, "substantially parallel" includes being parallel and, although not strictly parallel, being approximately parallel to the extent that a rectifying function, which will be described later, can be achieved. In this embodiment, the opening axis direction Y2 of each communication port 73 is substantially perpendicular to the opening axis direction Y1 of the exhaust port 63.

The total flow path cross-sectional area of the plurality of communication ports 73 should be substantially the same as the flow path cross-sectional area of the exhaust port 63 so that the flow rate of gas passing through the exhaust port 63 is not reduced by the exhaust port cover 7. is desirable.

FIG. 4 is a sectional view of the vicinity of the exhaust port 63 of the outer shell 22 showing the flow of exhaust gas in the exhaust port cover 7, and in this figure, the flow of exhaust gas is indicated by arrows. As shown in FIG. 4, when the vacuum pump 65 is connected to the exhaust pipe 64 and the vacuum pump 65 is operated, a forced exhaust flow is generated at the exhaust port 63. The gas in the intermediate chamber 25 enters into the exhaust pipe 64 through the communication port 73 of the exhaust port cover 7. Due to the rectification effect of the exhaust port cover 7, the flow of gas entering the exhaust pipe 64 from the intermediate chamber 25 through the exhaust port cover 7 becomes substantially parallel to the opening axis direction Y2 of the communication port 73. The flow of gas that has entered the exhaust pipe 64 is rectified by the exhaust pipe 64 substantially parallel to the opening axis direction Y1 of the exhaust port 63.

Since the lid 72 of the gas exhaust port cover 7 exists at the end of the exhaust port 63 in the opening axial direction Y1, and the passage of gas is blocked, the gas in the intermediate chamber 25 flows in the opening axial direction of the exhaust port 63. It is not possible to enter the exhaust port 63 substantially parallel to Y1. Therefore, in the intermediate chamber 25, around the exhaust port cover 7, a flow of exhaust gas substantially parallel to the opening axis direction Y2 of the communication port 73 occurs. The opening axis direction Y2 of the communication port 73 is substantially parallel to the in-plane direction of the surface of the laminated heat insulating material 27 around the exhaust port cover 7. In other words, around the exhaust port cover 7, almost no gas flow that pulls the laminated heat insulating material 27 in an out-of-plane direction occurs. Therefore, the laminated heat insulating material 27 around the exhaust port cover 7 is prevented from being peeled off or lifted up by the flow of exhaust gas and moved from the normal position, and the exhaust port 63 is blocked by the multilayer heat insulating material 27 that has moved from the normal position. You can prevent this from happening. In this way, the flow of exhaust gas is not obstructed by the laminated heat insulating material 27, so that the intermediate chamber 25 can be quickly evacuated to the target degree of vacuum.

In this embodiment, the multi-shell tank 11 is a transport tank included in the tank container 1, but the structure of the multi-shell tank 11 is such that it can be a storage tank installed on the ground or mounted on a floating structure such as a ship. It may also be applied to fuel tanks and storage tanks. Further, the multi-shell tank 11 is not limited to a double-shell tank, and may include three or more multi-shells. Regardless of the number of shells, the multi-shell tank in this case includes a first shell and a second shell adjacent to each other inside and outside, a laminated heat insulating material disposed between the first shell and the second shell, and a second shell. It is only necessary that the shell has an exhaust port for reducing the pressure in the space between the first shell and the second shell, and the exhaust port cover 7 is disposed at this exhaust port.

[Second embodiment]
Next, a second embodiment of the present disclosure will be described. FIG. 5 is a sectional view showing a schematic configuration of a vacuum multiplex tube 15 according to a second embodiment of the present disclosure. As shown in FIG. 5, the multi-shell structure according to the second embodiment is a vacuum multi-tube 15. The vacuum multiplex tube 15 is used, for example, as piping for passing liquid or gas at extremely low temperatures.

The vacuum multiplex tube 15 includes an inner shell 121 and an outer shell 122 surrounding the inner shell 121. Both the inner shell 121 and the outer shell 122 are tubes, and the inner shell 121 and the outer shell 122 constitute a double tube. Cryogenic liquid or gas is passed through the inner shell 121 . A hollow intermediate chamber 125 is formed between the inner shell 121 and the outer shell 122. A laminated heat insulating material 126 covering the inner shell 121 is arranged in the intermediate chamber 125 . Furthermore, the intermediate chamber 25 is in a vacuum state to suppress convective heat transfer, and the intermediate chamber 125 functions as a vacuum heat insulating layer.

Here, the exhaust structure of the intermediate chamber 125 will be explained. The outer shell 122 is provided with an exhaust port 163. Although one exhaust port 163 is shown in FIG. 5, the exhaust ports 163 may be provided at multiple locations on the outer shell 122. Although not particularly limited, in the example shown in FIG. 5, an exhaust pipe 164 that penetrates the outer shell 122 in the wall thickness direction is disposed in the outer shell 122, and an exhaust port 163 is formed by this exhaust pipe 164. There is. One end of the exhaust pipe 164 is disposed in the intermediate chamber 125, and the other end of the exhaust pipe 164 is disposed outside the outer shell 122 and is closed and opened by a valve 166. When the intermediate chamber 125 is evacuated, the vacuum pump 65 is connected to the exhaust pipe 164 via the valve 166 and piping, and the intermediate chamber 125 and the vacuum pump 65 are communicated with each other.

An exhaust port cover 7 is disposed at the exhaust port 163 in the intermediate chamber 125 . More specifically, the exhaust port cover 7 is attached to the end of the exhaust pipe 164. FIG. 6 is a sectional view of the vicinity of the exhaust port 163 of the outer shell 122 showing the structure of the exhaust port cover 7. As shown in FIG. As shown in FIG. 6, the structure of the exhaust port cover 7 is substantially the same as the structure of the exhaust port cover 7 according to the first embodiment, so it is possible to use the same or similar members as the first embodiment described above. The detailed explanation will be omitted.

The exhaust port cover 7 is arranged at the exhaust port 163 so that the main surface 72a of the lid 72 faces the surface of the laminated heat insulating material 126. Such an exhaust port cover 7 is arranged such that the extending direction of the body 71 is substantially parallel to the opening axis direction Y1 of the exhaust port 163.

In the vacuum multiple pipe 15 having the above configuration, when the vacuum pump 65 is connected to the exhaust pipe 164 and the vacuum pump 65 is operated, a forced exhaust flow is generated at the exhaust port 163. The gas in the intermediate chamber 125 enters the exhaust pipe 164 through the communication port 73 of the exhaust port cover 7 . Due to the rectification effect of the exhaust port cover 7, the flow of gas from the intermediate chamber 125 to the exhaust pipe 164 through the exhaust port cover 7 is substantially parallel to the opening axis direction Y2 of the communication port 73. The flow of gas that has entered the exhaust pipe 164 is rectified by the exhaust pipe 164 substantially parallel to the opening axis direction Y1 of the exhaust port 63.

Since the lid 72 of the exhaust port cover 7 is present at the end of the exhaust port 163 in the opening axis direction Y1, the gas in the intermediate chamber 125 flows toward the exhaust port cover 7 substantially parallel to the opening axis direction Y1 of the exhaust port 163. It is not possible to enter inside. Therefore, in the intermediate chamber 125, around the exhaust port cover 7, almost no exhaust gas flows substantially parallel to the opening axis direction Y1 of the exhaust port 163, and substantially parallel to the opening axis direction Y2 of the communication port 73. This creates a flow of exhaust gas. The opening axis direction Y2 of the communication port 73 is substantially parallel to the in-plane direction of the surface of the laminated heat insulating material 126 around the exhaust port cover 7. That is, around the exhaust port cover 7, almost no gas flow that pulls the laminated heat insulating material 126 in an out-of-plane direction occurs. Therefore, the laminated heat insulating material 126 around the exhaust port cover 7 is prevented from being peeled off or lifted up by the flow of exhaust gas and moved from the normal position, and the exhaust port 163 is blocked by the multilayer heat insulating material 126 that has moved from the normal position. You can prevent this from happening. In this way, the flow of exhaust gas is not obstructed by the laminated heat insulating material 126, so that the intermediate chamber 125 can be quickly evacuated to the target degree of vacuum.

[Summary]
The multi-shell structure 11; 15 according to the first item of the present disclosure is
First shell 21; 121;
A laminated insulation material 27; 126 surrounding the first shell 21; 121;
a second shell 22; 122 surrounding the laminated insulation material 27; 126 and having an exhaust port 63; 163;
an exhaust port cover 7 disposed on the exhaust port 63; 163 in the intermediate chamber 25; 125 between the first shell 21; 121 and the second shell 22; 122;
The exhaust port cover 7 includes a lid body 72 having a main surface 72a facing the surface of the laminated heat insulating material 27; The body 71 has a communication port 73 that communicates between the intermediate chamber 25; 125 and the exhaust port 63; be.
In the above, the multi-shell structure 11; 15 corresponds to the multi-shell tank 11 in the first embodiment and the vacuum multiple pipe 15 in the second embodiment, respectively. The first shell 21; 121 corresponds to the inner shell 21 in the first embodiment and the inner shell 121 in the second embodiment, respectively. Further, the second shell 22; 122 corresponds to the outer shell 22 in the first embodiment and the outer shell 122 in the second embodiment.

In the multi-shell structure 11; 15 configured as described above, when suction force is generated at the exhaust port 63; 163 to forcibly exhaust the intermediate chamber 25; 125, the gas in the intermediate chamber 25; It reaches the exhaust port 63; 163 through the communication port 73. Due to the rectifying action of the exhaust port cover 7, the flow of gas from the intermediate chamber 25 through the exhaust port cover 7 to the exhaust port 63; 163 becomes substantially parallel to the opening axis direction Y2 of the communication port 73. Therefore, in the intermediate chamber 25; 125, around the exhaust port cover 7, a flow of exhaust gas substantially parallel to the opening axis direction Y2 of the communication port 73 occurs. The opening axis direction Y2 of the communication port 73 is substantially parallel to the in-plane direction of the surface of the laminated heat insulating material 27; 126 around the exhaust port cover 7. That is, around the exhaust port cover 7, almost no gas flow that pulls the laminated heat insulating material 27; 126 in an out-of-plane direction occurs. Therefore, the laminated heat insulating material 27; 126 around the exhaust port cover 7 is prevented from peeling off or floating due to the exhaust flow and moving from the fixed position, and the laminated heat insulating material 27; 126 that has moved from the fixed position closes the exhaust port. 63; 163 can be prevented from being blocked. In this way, the flow of exhaust gas is not obstructed by the laminated heat insulating material 27; 126, so that the intermediate chamber 25; 125 can be quickly evacuated to the target degree of vacuum.

The multi-shell structure 11; 15 according to the second item of the present disclosure is the multi-shell structure 11; 15 according to the first item, in which a plurality of communication ports 73 are distributed and arranged in the body 71. It is.

Thereby, the gas in the intermediate chamber 25; 125 can be dispersed from a plurality of locations around the exhaust port cover 7 and enter the exhaust port 63; 163.

In the multi-shell structure 11; 15 according to the third item of the present disclosure, in the multi-shell structure 11; 15 according to the second item, the sum of the opening areas of the plurality of communication ports 73 is The opening area is substantially the same as that of the opening area.

Thereby, the degree of decrease in the flow rate of gas passing through the exhaust port 63; 163 due to the exhaust port cover 7 can be reduced.

The multi-shell structure 11 according to the fourth item of the present disclosure is arranged between the first shell 21 and the laminated heat insulating material 27 in the multi-shell structure 11 according to any one of the first to third items. A heat shield 24 surrounding the first shell 21 is further provided.

In this way, the multi-shell tank 11 is equipped with the heat shield 24 that shields the first shell 21 from radiant heat, so the multi-shell tank 11 is suitable as a transport container included in the tank container 1.

The above discussion of the disclosure has been presented for purposes of illustration and description, and is not intended to limit the disclosure to the form disclosed herein. For example, although in the foregoing Detailed Description, various features of the disclosure are grouped into two embodiments for the purpose of streamlining the disclosure, some of the features may be combined. Additionally, features included in this disclosure may be combined in alternative embodiments, configurations, or aspects other than those discussed above.

1: Tank container 7: Exhaust port cover 11: Multi-shell tank (an example of a multi-shell structure)
15: Vacuum multiple tube (an example of a multi-shell structure)
21,121: Inner shell (an example of the first shell)
22,122: Outer shell (an example of the second shell)
24: Heat shield 25, 125: Intermediate chamber 26, 27, 126: Laminated insulation material 63, 163: Exhaust port 64, 164: Exhaust pipe 71: Body 72: Lid body 72a: Main surface 73: Communication port Y2: Opening axis direction

Claims (4)

The first shell,
a laminated insulation material surrounding the first shell;
a second shell surrounding the laminated insulation material and having an exhaust port;
an exhaust port cover disposed over the exhaust port in an intermediate chamber between the first shell and the second shell;
The exhaust port cover connects a lid body having a main surface facing the surface of the laminated heat insulating material surrounding the exhaust port cover, and the lid body and the exhaust port, and connects the intermediate chamber and the exhaust port. a body having a communication port that communicates with the exhaust port and whose opening axis direction is substantially parallel to the main surface of the lid;
Multi-shell structure. a plurality of the communication ports are distributed and arranged in the body;
The multi-shell structure according to claim 1. the sum of the opening areas of the plurality of communication ports is substantially the same as the opening area of the exhaust port;
The multi-shell structure according to claim 2. further comprising a heat shield disposed between the first shell and the laminated insulation and surrounding the first shell;
The multi-shell structure according to claim 1 or 2.

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