JP4984323B2 - Vacuum insulated container - Google Patents

Description

  The present invention relates to a vacuum heat insulating container that contains a cryogenic refrigerant and keeps it cool. In particular, the present invention relates to a vacuum heat insulating container that contains a cryogenic liquid refrigerant in a terminal structure of a superconducting cable line and keeps it cool.

  As a configuration for storing a cryogenic refrigerant, a cryogenic container (vacuum insulation container) using a vacuum insulation system is known (for example, Patent Document 1 and Patent Document 2). The vacuum heat insulation container includes a refrigerant tank that stores the refrigerant and a vacuum tank that covers the outer periphery of the refrigerant tank, and forms a vacuum heat insulating layer between the refrigerant tank and the vacuum tank so that the refrigerant stored in the refrigerant tank can be stored. This is a container that is kept at a very low temperature.

  Further, the configuration of the vacuum heat insulating container is also applied to a terminal structure in a superconducting cable line in which cooling with a refrigerant is essential (for example, Patent Document 3). As a typical configuration of the terminal structure of a superconducting cable line, a structure shown in FIG. 10 is known. In this terminal structure, a connecting conductor 210 is connected to the end of the superconducting cable, and the connecting conductor 210 and the end of the normal conducting conductor 220 on the room temperature side are connected via a joint portion 270. Further, this terminal structure includes a refrigerant tank 230 in which one end of the connection conductor 210 and one end of the normal conductor 220 (connection side to the connection conductor 210) is disposed, a vacuum tank 240 that covers the refrigerant tank 230, and a vacuum tank 240 includes a soot pipe 250 protruding from the room temperature side and a bushing 260 covering the outer periphery of the normal conducting conductor 220. By providing such a configuration, the temperature of the refrigerant can be efficiently maintained in the terminal structure of the superconducting cable.

JP-A-62-266371 JP 63-213906 A JP 2002-238144 A

  However, since the degree of vacuum of the vacuum heat insulation layer in the vacuum heat insulation container changes depending on the surface temperature of the outer peripheral surface of the refrigerant tank storing the refrigerant, there is a possibility that the degree of vacuum may decrease with time. This is mainly because gas molecules adsorbed on the outer peripheral surface of the refrigerant tank are released to the vacuum heat insulating layer as time passes.

  In general, the lower the temperature of the wall surface on which the gas molecules are adsorbed, the longer the time (stay time) that the gas molecules remain adsorbed on the wall surface, and the average stay time at the liquid nitrogen temperature is on the order of years. Are known. In other words, there are few gas molecules that freely move in the vacuum heat insulating layer at the liquid nitrogen temperature, and even if the vacuum heat insulating layer has achieved a predetermined degree of vacuum, the liquid nitrogen temperature will be exceeded over time. There is a possibility that gas molecules adsorbed on the outer peripheral surface of the refrigerant tank are released and the vacuum heat insulating layer cannot maintain a predetermined degree of vacuum.

  Here, in most cases, the liquid refrigerant is in a gasified state above the refrigerant tank, and it is virtually impossible to fill the refrigerant tank with the liquid refrigerant. Therefore, the temperature on the outer peripheral surface of the refrigerant tank is higher on the upper side of the container than on the lower side of the container, and the gas molecules adsorbed on the outer peripheral surface of the upper refrigerant tank are easily released with time. As a result, the degree of vacuum of the entire vacuum heat insulating layer decreases (pressure increases), the heat insulating performance of the vacuum heat insulating container decreases, and evaporation of the refrigerant in the refrigerant tank is promoted.

  If the evaporation of the refrigerant as described above promotes further evaporation of the refrigerant, there is a possibility that the purpose of the vacuum heat insulating container for keeping the liquid refrigerant cold cannot be achieved. In particular, in the case of a superconducting cable line, if the amount of liquid refrigerant is excessively reduced, the operation of the line may be hindered. In order to solve such problems, it is conceivable that a vacuum pump is always connected to the vacuum heat insulation layer and evacuation is continued. It is difficult to say that it is practical.

  Therefore, a main object of the present invention is to provide a vacuum heat insulating container capable of stably keeping a liquid refrigerant for a long time with a simple configuration.

  The vacuum heat insulation container of this invention is a vacuum heat insulation container provided with the refrigerant tank which stores the refrigerant | coolant which consists of a liquid phase and a gaseous phase, and the vacuum tank which covers the outer periphery of a refrigerant tank. And the vacuum heat insulation container of this invention has a partition part which divides | segments the vacuum heat insulation layer formed between a refrigerant tank and a vacuum tank into an upper heat insulation layer and a lower heat insulation layer.

  The refrigerant | coolant stored in the vacuum heat insulation container of this invention is a thing with the intended use condition in a liquid state. For example, examples of the refrigerant include liquid nitrogen, liquid helium, liquid oxygen, and liquid air. These refrigerants can hardly be stored only in the liquid state when stored in the refrigerant tank. Therefore, the stored refrigerant is divided into a liquid phase and a gas phase.

  Here, in the configuration of the vacuum heat insulating container of the present invention, the partition part makes the lower heat insulating layer mainly covering the outer peripheral side of the part in contact with the liquid phase part of the refrigerant in the refrigerant tank, and the part in contact with the gas phase part of the refrigerant. It can be set as the independent space which isolate | separated from the upper heat insulation layer which mainly covers the outer peripheral surface. As already explained, the lower the temperature of the refrigerant tank, the more difficult the gas molecules adsorbed on the outer peripheral surface of the refrigerant tank are released from the outer peripheral surface. In other words, the refrigerant tank outer peripheral surface in the upper heat insulating layer is easier to release gas molecules than the refrigerant tank outer peripheral surface in the lower heat insulating layer. For this reason, the degree of vacuum of the upper heat insulating layer tends to be lower than the degree of vacuum of the lower heat insulating layer. However, in the vacuum heat insulating container of the present invention, since the upper heat insulating layer and the lower heat insulating layer are independent spaces, even if the vacuum degree of the upper heat insulating layer is lowered, the influence does not reach the lower heat insulating layer. That is, the vacuum degree of the lower heat insulating layer can be maintained in a long state with a simple configuration in which the vacuum heat insulating layer is partitioned. As a result, the liquid refrigerant can be kept cold stably over a long period of time.

  Hereafter, each structure of this invention is demonstrated in detail.

  A partition part will not be specifically limited if it is a structure which can divide | segment a vacuum heat insulation layer into the independent space. However, it is preferable that the partition part has the lower end of the portion connected to the refrigerant tank at a position below the liquid level when using the vacuum heat insulating container. More preferably, the lower end is below the liquid level. Here, since the lower heat insulation layer is less likely to lower the degree of vacuum than the upper heat insulation layer and has better heat insulation performance, the temperature of the part of the refrigerant tank surrounded by the lower vacuum tank is the refrigerant tank surrounded by the upper vacuum tank. It is maintained at a temperature lower than the temperature of the portion. Therefore, if the lower end of the partition portion is below the liquid level when using the vacuum heat insulating container, most of the liquid refrigerant comes into contact with the low temperature part of the refrigerant tank surrounded by the lower heat insulating layer. It will be difficult to evaporate.

  The partition part selects the material and shape which have the mechanical strength which can partition a vacuum heat insulation layer airtightly and can maintain an upper heat insulation layer and a lower heat insulation layer. As a material, for example, stainless steel or copper can be used in consideration of a coefficient of thermal expansion in addition to mechanical strength. Moreover, as a shape, in order to suppress the heat conduction from the external environment through a partition part, using a thin shape, for example, a flat plate shape or a corrugated plate shape (bellows), is used. Can be mentioned. In particular, in the case of the bellows, since the heat conduction distance from the vacuum tank to the refrigerant tank can be increased, heat conduction from the vacuum tank to the refrigerant tank can be suppressed.

  It is preferable that the upper heat insulating layer and the lower heat insulating layer partitioned by the partition portion can be appropriately evacuated. For example, a vacuum port communicating with each of the upper heat insulating layer and the lower heat insulating layer is formed in the vacuum chamber. With such a configuration, both the heat insulating layers can be appropriately evacuated, so that a high degree of vacuum is easily maintained.

  In order to maintain the vacuum degree of the vacuum heat insulating layer, an adsorbent that adsorbs gas molecules (for example, getter alloy containing zirconium, activated carbon, aluminum oxide, etc.) is adsorbed on at least the upper heat insulating layer side of the vacuum heat insulating layer. It is preferable to arrange. As already described, gas molecules are likely to be released from the outer peripheral surface of the refrigerant tank on the upper heat insulating layer side with the passage of time, and the degree of vacuum of the upper heat insulating layer is likely to decrease. Therefore, when the adsorbent is arranged on the upper heat insulating layer side, it is possible to suppress a decrease in the degree of vacuum on the upper heat insulating layer side. That is, it is preferable to arrange an adsorbent that adsorbs gas molecules at least on the upper heat insulating layer side in the partition. Since a partition part is a structure which partitions a vacuum heat insulation layer up and down, arrangement | positioning of an adsorbent can be performed only by mounting an adsorbent in a partition part. Of course, the adsorbent may be disposed also on the lower heat insulating layer side, and in that case, the adsorbent may be disposed at the position of the partition portion.

  Moreover, it is preferable to arrange | position the heat insulating material in the vacuum heat insulating layer, especially the heat insulating material which suppresses the heat conduction by radiation. As such a heat insulating material, super insulation (hereinafter referred to as SI), which is a laminate of polypropylene mesh and aluminum foil, can be suitably used. The arrangement of SI may be made by stacking sheet-like SI in the vertical direction of the vacuum heat insulation layer, but it is preferable to arrange the SI so that the SI forms a layer in the radial direction of the vacuum heat insulation container. . If the SI is arranged so as to form a layer in the radial direction, the plane of the SI faces the radial direction of the heat insulating container, so that the radiation can be efficiently reflected.

  By the way, when a heat insulating material such as SI is disposed on the entire vacuum heat insulating layer, the heat insulating performance of the vacuum heat insulating layer is improved, but it is difficult to evacuate the vacuum heat insulating layer. Therefore, by limiting the position where the heat insulating material is disposed, the vacuum heat insulating layer can be easily evacuated while effectively exerting the advantage of disposing the heat insulating material. For example, the heat insulating material is disposed in the vicinity of at least one of the upper heat insulating layer side and the lower heat insulating layer side of the partition portion. By disposing the heat insulating material at this position, it is possible to suppress the heat generation of the partition portion due to radiation and suppress the temperature rise of the refrigerant tank.

  In the vacuum heat insulating container, the refrigerant tank, the vacuum tank, and the partitioning part may be integrally formed at the time of manufacture, or each of the above components may be separate members, and these members may be appropriately assembled on site. Further, at least one of the refrigerant tank and the vacuum tank may be formed by further combining two or more divided pieces. If the vacuum heat insulating container is integrally formed, its quality, particularly the joint between the partition part and the refrigerant tank and the airtightness of the joint part between the partition part and the vacuum tank can be inspected in detail. Therefore, it can be set as a reliable vacuum heat insulation container. On the other hand, if it is a vacuum heat insulation container which can be divided into a plurality of members, the container can be easily transported to the site of use.

  Here, when at least one of the refrigerant tank and the vacuum tank is composed of two or more divided pieces, the tank is preferably a divided piece that is divided in the vertical direction. When both the refrigerant tank and the vacuum tank are composed of two or more divided pieces, it is preferable to form a unit in which the divided pieces of the refrigerant tank and the divided pieces of the vacuum tank are connected in advance by a partitioning portion. And when forming a vacuum heat insulation container using this unit, what is necessary is just to assemble this unit, the remaining refrigerant tank division piece, and a vacuum tank division piece. If it is the structure which uses this unit, it is not necessary to form the partition part which divides | segments a vacuum heat insulation layer up and down on-site, and an upper and lower heat insulation layer can be divided reliably in an airtight state.

  Moreover, when comprising a vacuum heat insulation container from a division piece, it is preferable to provide a flange so that division pieces may be easily joined when each division piece is assembled into a vacuum heat insulation container. For example, when the refrigerant tank is composed of a plurality of divided pieces, a flange is provided on the end face of the divided refrigerant tank. And when joining the split pieces, the flanges of the split pieces are overlapped and tightened. Similarly, when the vacuum chamber is composed of a plurality of divided pieces, a flange is provided on the end face of the divided vacuum chamber.

  The vacuum heat insulating container of the present invention described above can be applied to various configurations. For example, the vacuum heat insulating container of the present invention may be used simply as a container that can be transported in a state in which liquid refrigerant is stored, or a device that is placed in a state in which liquid refrigerant is stored and needs to be cooled by liquid refrigerant. You may use as a container which supplies a refrigerant | coolant to etc. In particular, as the latter configuration, there is a terminal structure of a superconducting cable line described in Examples described later.

  According to the configuration of the present invention, since the vacuum heat insulating layer is divided into the upper heat insulating layer and the lower heat insulating layer, even when the vacuum degree of the upper heat insulating layer is lowered, the vacuum degree of the entire vacuum heat insulating layer is not lowered. . Since the lower heat insulating layer mainly covers the outer peripheral surface of the refrigerant tank in contact with the liquid phase, the liquid refrigerant in the refrigerant tank is allowed to flow for a long time if the degree of vacuum of the lower heat insulating layer is maintained at a high level. It can be stably kept cool.

  Hereinafter, the vacuum heat insulation container of this invention is demonstrated based on figures.

<Example 1>
(Overall structure of vacuum insulation container)
FIG. 1 is a vertical cross-sectional view of the vacuum heat insulating container of this example, and FIG. 2 is a partial cross-sectional perspective view of each component of the vacuum heat insulating container. The vacuum heat insulating container 1 includes a refrigerant tank 10 that stores the liquid refrigerant LN and a vacuum tank 20 that covers the outer periphery of the refrigerant tank 10, and the upper part of each tank is sealed with a lid 40. A vacuum heat insulating layer 30 that is evacuated is formed between the refrigerant tank 10 and the vacuum tank 20, and the vacuum heat insulating layer 30 is further separated from the upper heat insulating layer 30u by the partition plate (partition part) 90. It is divided into the layer 30d. Here, the partition plate 90 divides the vacuum heat insulating layer 30, but does not divide the inside of the refrigerant tank 10.

(Each component of vacuum insulation container)
[Refrigerant]
In this example, the liquid refrigerant (liquid phase) LN stored in the refrigerant tank is nitrogen. The stored nitrogen is stored in the refrigerant tank in a liquid state, but a part of the nitrogen is in a gas state to form a gas phase GN. The temperature of the liquid phase LN is about 70 to 77K, and the temperature of the gas phase GN is about 80 to 100K. Note that the refrigerant is not limited to nitrogen, and may be helium, oxygen, air, or the like, for example.

[Refrigerant tank]
The refrigerant tank 10 of this example includes an upper refrigerant tank container 10u, a lower refrigerant tank container 10d, and a part of a partition plate (see FIG. 1). That is, the inner peripheral surface of the lower refrigerant tank container 10d, the inner peripheral surface of the hole of the partition plate 90 (see FIG. 2), the inner peripheral surface of the upper refrigerant tank container 10u, and the lower surface of the lid 40 are surrounded. Refrigerant can be stored in the space and kept cold.

  The lower refrigerant tank container 10d is a bottomed cylindrical member made of stainless steel, and an annular flange 11 that protrudes inward in the radial direction of the cylinder is provided on the upper end surface thereof. A packing groove 51ag in which the annular packing 51a can be arranged is formed on the surface of the annular flange 11 on the opening end side of the lower refrigerant tank container 10d. The annular flange 11 is provided with a plurality of bolt holes 61a penetrating the annular flange 11 in the thickness direction at equal intervals in the circumferential direction of the annular flange 11. The bolt hole 61a is provided on the inner peripheral side of the annular flange 11 with respect to the packing groove 51ag. In the drawings, only four of the plurality of bolt holes are described, and similarly, only four bolt holes are described in the subsequent drawings.

  On the other hand, the upper refrigerant tank container 10u is a stainless steel cylindrical member opened at both ends, and annular flanges 12 and 13 are provided on both end surfaces to project radially inward of the cylinder. A packing groove 52ag in which the annular packing 52a can be disposed is formed on the surface of the annular flange 12 on the side facing the lower refrigerant tank container 10d. In addition, a plurality of bolt holes 62 a penetrating in the thickness direction of the annular flange 12 are arranged in the annular flange 12 at equal intervals in the circumferential direction of the annular flange 12. The position of the bolt hole 62a of the annular flange 12 is provided on the inner peripheral side of the flange 11 with respect to the packing groove 52ag, and coincides with the bolt hole 61a of the flange 11 of the lower refrigerant tank container 10d. On the other hand, a plurality of bolt holes 63 a penetrating in the thickness direction of the annular flange 13 are arranged in the annular flange 13 at equal intervals in the circumferential direction of the annular flange 13.

[Vacuum chamber]
Similarly to the refrigerant tank 10, the vacuum tank 20 also includes an upper vacuum tank container 20u, a lower vacuum tank container 20d, and a part of the partition plate 90. That is, the space surrounded by the inner peripheral surface of the upper vacuum vessel container 20u, the upper surface of the partition plate 90, the lower surface of the lid 40, and the outer peripheral surface of the upper refrigerant vessel container 10u described above forms the upper heat insulating layer 30u. Further, a space surrounded by the inner peripheral surface of the lower vacuum chamber container 20d, the lower surface of the partition plate 90, and the outer peripheral surface of the lower refrigerant layer container 10d described above forms the lower heat insulating layer 30d. The upper vacuum chamber container 20u and the lower vacuum chamber container 20d are provided with vacuum ports 72 and 71, respectively, so that the upper heat insulating layer 30u and the lower heat insulating layer 30d can be evacuated.

  The lower vacuum tank container 20d is a bottomed cylindrical member made of stainless steel, and the lower refrigerant tank container 10d can be accommodated therein. A support member 81 that supports the lower refrigerant tank container 10d at the bottom of the lower vacuum tank container 20d and separates so that the inner peripheral surface of the lower vacuum tank container 10d and the outer peripheral surface of the lower refrigerant tank container 20d are not in direct contact with each other. Is provided. The support member 81 is a short rod-like member, and there is little heat conduction from the vacuum chamber 20 to the refrigerant tank 10 via the support member 81. The support member 81 may be formed of a member having low thermal conductivity, such as fiber reinforced plastic (FRP).

  The height of the lower vacuum vessel container 20d is such that when the lower refrigerant vessel container 10d is accommodated therein and the vessel 10d is supported by the support member 81, the opening end face of the lower vacuum vessel vessel 20d and the lower refrigerant vessel 10d It is comprised so that it may become flush with the opening end surface of.

  An annular flange 21 protruding outward in the radial direction of the cylinder is provided on the open end face of the lower vacuum chamber container 20d. A packing groove 51bg into which the annular packing 51b is fitted is formed on the surface of the annular flange 21 on the opening end face side of the lower vacuum chamber container 20d. The annular flange 21 is provided with a plurality of bolt holes 61b penetrating the annular flange 21 in the thickness direction at equal intervals in the circumferential direction of the annular flange 21. The bolt hole 61b is provided on the outer peripheral side of the annular flange 21 with respect to the packing groove 51bg.

  On the other hand, the upper vacuum tank container 20u is a stainless steel cylindrical member having both ends opened, and the height thereof is configured to coincide with the height of the upper refrigerant tank container 10u. In addition, annular flanges 22 and 23 are provided on both end surfaces of the upper vacuum chamber container 20u so as to project outward in the radial direction of the cylinder. A packing groove 52bg into which the packing 52b is fitted is provided on the surface of the annular flange 22 facing the lower vacuum chamber container 20d. Further, a plurality of bolt holes 62 b penetrating in the thickness direction of the annular flange 22 are arranged in the annular flange 22 at equal intervals in the circumferential direction of the annular flange 22. The position of the bolt hole 62b of the annular flange 22 is provided on the outer peripheral side of the flange 22 with respect to the packing groove 52bg, and coincides with the bolt hole 61b of the flange 21 of the lower vacuum vessel 20d. In addition, a plurality of bolt holes 63 b penetrating in the thickness direction of the annular flange 23 are also arranged in the annular flange 23 at equal intervals in the circumferential direction of the annular flange 23.

[Partition plate]
The partition plate 90 is an annular stainless steel thin plate. The thickness of the partition plate 90 is made as thin as possible while having a strength capable of maintaining airtightness between the upper heat insulating layer 30u and the lower heat insulating layer 30d. In this partition plate 90, the portion exposed to the vacuum heat insulating layer 30 may be processed into a corrugated plate like Example 2 described later. In addition, as a material of the partition plate 90, what has predetermined intensity | strengths, such as alloys other than stainless steel and fiber reinforced plastics, can be used.

  Further, the partition plate 90 is provided with a plurality of bolt holes 65a and 65b penetrating in the thickness direction. The bolt holes 65a are provided at positions corresponding to the bolt holes 62a of the upper refrigerant tank container 10u and the bolt holes 61a of the lower refrigerant tank container 10d. The bolt hole 65b is provided at a position that coincides with the bolt hole 62b of the upper vacuum chamber container 20u and the bolt hole 61b of the lower vacuum chamber container 20d.

[lid]
The lid 40 is a stainless steel disk. The lid 40 is formed with annular packing grooves 54ag, 54bg along the shapes of the flange 13 of the upper refrigerant vessel 10u and the flange 23 of the upper vacuum vessel 20u. In these packing grooves 54ag and 54bg, annular packings 54a and 54b can be fitted, respectively.

  The lid 40 is provided with a plurality of bolt holes 64a and 64b penetrating in the thickness direction, the bolt holes 64a being radially inward of the packing grooves 54ag, and the bolt holes 64b being the packing grooves. It is provided radially outward from 54bg. The bolt hole 64a is provided at a position that coincides with the bolt hole 63a of the upper refrigerant tank container 10u when the lid 40 is disposed on the upper refrigerant tank container (upper vacuum tank container). The bolt hole 64b is provided at a position that coincides with the bolt hole 63b of the upper vacuum chamber container 20u. Furthermore, the lid 40 is provided with a refrigerant inlet, a gas vent hole, and the like (not shown) that make the refrigerant tank 10 and the outside of the container 1 communicate with each other as necessary.

[Packing]
The packings 51a, 51b, 52a, 52b, 54a, 54b are annular members for maintaining the airtightness between the divided pieces. Each packing has a diameter that matches the shape of the corresponding packing groove of each component. The material of the packing may be an elastic body that can be used even in an extremely low temperature state, such as fluoro rubber (Viton: registered trademark).

(Assembly procedure of vacuum insulation container)
In order to produce the vacuum heat insulating container 1 having the above configuration, first, the lower refrigerant tank container 10d is placed inside the lower vacuum tank container 20d. Next, the packing 51a and the packing 51b are fitted into the packing groove 51ag of the lower refrigerant tank container 10d and the packing groove 51bg of the lower vacuum tank container 20d, respectively, and the partition plate 90 is placed on these packings.

  Next, the upper refrigerant tank container 10u in which the packing 52a is fitted in the packing groove 52ag and the upper vacuum tank container 20u in which the packing 52b is fitted in the packing groove 52bg are arranged on the partition plate 90. Then, with the bolt holes of the upper and lower refrigerant tank containers, the upper and lower vacuum tank containers, and the partition plate 90 matched, the upper and lower refrigerant tank containers and the upper and lower vacuum tank containers are respectively bolted. Connect with

  Finally, packings 54a and 54b are fitted into the packing grooves 54ag and 54bg of the lid 40, and the lid 40 covers the openings of the refrigerant tank 10 and the vacuum tank 20. Then, the bolt hole 64a of the lid 40 and the bolt hole 63a of the upper refrigerant tank container 10u are matched, and the bolt hole 64b of the lid 40 and the bolt hole 63b of the upper vacuum tank container 20u are matched. In this manner, the lid 40 is bolted to the refrigerant tank 10 and the vacuum tank 20. By doing so, the refrigerant tank 10 is sealed, and the vacuum heat insulating layer 30 is divided into an upper heat insulating layer 30u and a lower heat insulating layer 30d and sealed.

  When the liquid refrigerant LN is stored in the vacuum heat insulating container 1, it is injected from the refrigerant inlet of the lid 40 so that the liquid level of the refrigerant is higher than that of the partition plate 90. When the refrigerant is injected, the evacuation of the upper heat insulating layer 30u and the lower heat insulating layer 30d is completed in advance. Of course, both layers can be evacuated after the refrigerant is injected.

  According to the vacuum heat insulating container 1 of this example, gas molecules are transferred from the outer peripheral surface of the upper refrigerant tank container 10u whose temperature is higher than that of the lower refrigerant tank container 10d by the refrigerant (gas phase GN) in a gas state from the upper heat insulating layer 30u. Even when the degree of vacuum of the heat insulating layer 30u is reduced, the degree of vacuum of the lower heat insulating layer 30d does not decrease due to the influence. Therefore, the liquid refrigerant LN can be stably cooled for a long period of time by the heat insulating effect of the lower heat insulating layer 30d that covers the outer periphery of the lower refrigerant tank container 10d that actually stores the liquid refrigerant LN.

<Example 2>
In Example 2, a vacuum heat insulating container having a partition configuration different from that in Example 1 will be described. In this example, only differences in configuration from the first embodiment will be described, and the same components as those in the first embodiment will be denoted by the same reference numerals and description thereof will be omitted.

  FIG. 3 is a longitudinal sectional view of the vacuum heat insulating container of Example 2. As shown in the figure, the vacuum heat insulating container 2 is a unit Un1 in which the partition portion is a corrugated plate (bellows 91), and the upper refrigerant tank container 10u and the upper vacuum tank container 20u are connected in advance by the bellows 91. Is forming.

  The unit Un1 will be described more specifically. As shown in FIG. 4, the unit Un1 is integrally connected by a bellows 91 and a support rod 82 in a state where the upper refrigerant tank container 10u is housed in the upper vacuum tank container 20u. is there. The bellows 91 is provided over the entire circumference of the container 10u, and the upper and lower spaces are completely partitioned with the bellows 91 as a boundary. On the other hand, the support rod 82 extends from the upper refrigerant tank container 10u toward the upper vacuum tank container 20u, and holds the upper vacuum tank container 20u and the upper refrigerant tank container 10u at an interval (thermal conductivity such as FRP). A plurality of materials arranged at equal intervals in the circumferential direction of the container 10u. The support rod 82 is used to temporarily fix the upper refrigerant tank container 10u and the upper vacuum tank container 20u so as not to shift before assembling the vacuum heat insulating container 2. The bellows 91 is used for both tank containers 10u. , 20u is not necessary if it can be fixed securely.

  When the unit Un1 is used to manufacture the vacuum heat insulating container 2 of FIG. 3, the lower refrigerant tank container 10d is accommodated inside the lower vacuum tank container 20d, and the unit Un1 is placed on these and bolted. At the same time, it is only necessary to bolt the lid 40 on the unit Un1. At this time, by placing an adsorbent 85 that adsorbs gas molecules and a super insulation (heat insulating material) 86 that reflects radiation on the upper heat insulating layer 30u side of the bellows 91, the cold insulation property of the container 2 is increased. Can be improved.

  Further, if the vacuum insulation container 2 uses the unit Un1, there is no need to perform the work of providing the bellows (partition part) 91 at the site. That is, before the container 2 is assembled, since the precise airtight test has already been completed for the partition portion, the highly reliable container 2 can be easily assembled on site.

<Modification>
As a configuration similar to the configuration of the second embodiment, a vacuum heat insulating container may be formed using the unit Un2 shown in FIG. In this unit Un2, the partition plate 90 of Example 1 is formed integrally with the upper vacuum chamber container 20u and the lower vacuum chamber container 10u. Even when this unit Un2 is used, it is possible to easily assemble the vacuum insulation container on site. The position of the partition plate 90 may be changed as appropriate.

  Furthermore, a vacuum heat insulating container may be formed using the unit Un3 and the unit Un4 shown in FIG. The unit Un3 is a unit in which a lower refrigerant tank container 10d and a lower vacuum tank container 20d are integrally formed by a partition plate 90. With this unit Un3, the lower heat insulating layer 30d can be evacuated at the factory, and the lower heat insulating layer 30d can be brought into a high vacuum state in advance before the vacuum heat insulating container is assembled on site. That is, when assembling the container, it is not necessary to evacuate the lower heat insulating layer 30d, and the lower heat insulating layer 30d in a high vacuum state already inspected at the factory can be obtained. On the other hand, the unit Un4 is a unit in which the upper refrigerant tank container 10u and the upper vacuum tank container 20u are connected by the support rod 82. If these units Un3 and Un4 are used, the unit Un3 and the unit Un4 can be connected, and a vacuum insulation container can be formed simply by attaching a lid. Assembling efficiency is good.

<Example 3>
In Example 3, a vacuum heat insulating container in which the refrigerant tank and the vacuum tank are each divided into three in the vertical direction will be described. In this example, since there are many configurations in common with the second embodiment, the same components as those in the second embodiment are denoted by the same reference numerals and description thereof is omitted.

  FIG. 7 shows a longitudinal sectional view of the vacuum heat insulating container of this example. In the vacuum heat insulating container 3 of this example, a unit Un5 is provided above the lower refrigerant tank container 10d and the lower vacuum tank container 20d, and an upper refrigerant tank container 10uu and an upper vacuum tank container 20uu are provided above the unit Un5. Is provided. That is, in this container 3, the lower refrigerant tank container 10d, the upper refrigerant tank container 10u of the unit Un5, and the upper refrigerant tank container 10uu form the refrigerant tank 10, and the lower vacuum tank container 20d and the upper vacuum tank of the unit Un5. A vacuum tank 20 is formed by the tank container 20u and the upper vacuum tank container 20uu.

  The unit Un5 has substantially the same configuration as the unit Un1 of the second embodiment described with reference to FIG. 4, and the main difference is that an annular for fitting the packings 55a and 55b into the flanges 13 and 23. The packing groove is provided. The packing groove into which the packing 55a is fitted is provided on the upper surface of the flange 13 at a position radially outward from the bolt hole 63a. On the other hand, the packing groove into which the packing 55b is fitted is provided on the upper surface of the flange 23 at a position radially inward from the bolt hole 63b.

  Further, the upper refrigerant tank container 10uu and the upper vacuum tank container 20uu have the same configuration as the upper refrigerant tank container 10u and the upper vacuum tank container 20u described with reference to FIG. That is, the upper refrigerant tank container 10uu has flanges 14 and 15 and can be connected to the upper refrigerant tank container 10u of the unit Un5. The upper vacuum tank container 20uu has flanges 24 and 25, and the unit Un5 The upper vacuum chamber container 20u can be connected. Note that the upper tank container may have an integrated configuration like the unit Un4 described with reference to FIG.

  According to the configuration of this example, since the number of divisions of the container 3 is large, even a container with an increased volume of the entire container, that is, a container with an increased storage amount of liquid refrigerant can be easily transported.

<Example 4>
In Example 4, a vacuum heat insulating container in which a refrigerant tank, a vacuum tank, and a partition part are integrally manufactured in advance will be described. Also in this example, the same components as those in the above-described embodiment are denoted by the same reference numerals and description thereof is omitted.

  FIG. 8 is a longitudinal sectional view of the vacuum heat insulating container 4 of the fourth embodiment. As shown in the drawing, the vacuum heat insulating container 4 of this example is positioned in a state where the refrigerant tank 10 is stored in the vacuum tank 20 in advance, and the vacuum heat insulating layer 30 is further partitioned by a partition plate 92. The upper part of the refrigerant tank 10 and the vacuum tank 20 is sealed with a lid 40.

  In order to manufacture the vacuum heat insulating container 4, first, the refrigerant tank 10 in which an annular partition plate (partition part) 92 is welded to the outer peripheral surface is manufactured. The outer diameter of the partition plate 92 is the same as the outer diameter of the upper vacuum chamber container 20u and the lower vacuum chamber container 20d. Next, the produced refrigerant tank 10 with the partition plate 92 is fitted into the lower vacuum chamber container 20d, and the partition plate 92 and the lower vacuum chamber container 20d are welded. Then, as shown in the figure, the upper vacuum chamber container 20u is disposed and welded to the upper surface side of the partition plate 92. Finally, the lid 40 is bolted to the upper vacuum vessel container 20u and the refrigerant vessel 10. The manufactured vacuum heat insulating container 4 may be shipped in a state where the heat insulating layers 30u and 30d are evacuated.

  In such a vacuum heat insulating container 4, the arrangement of all the components has already been completed at the shipping stage, and the airtightness of each part is guaranteed. Therefore, it is possible to obtain a highly reliable vacuum heat insulating container 4. Since the vacuum heat insulating container 4 is integrally molded, it is preferable to use a small container for transporting liquid refrigerant rather than a large container.

<Example 5>
In Example 5, an example in which the configuration of the vacuum heat insulating container of the present invention is applied to the terminal structure of a superconducting cable line will be described. In addition, about the structure similar to the member already demonstrated in Examples 1-4, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

  The terminal structure of the superconducting cable has a configuration in which the normal conducting conductor and the superconducting conductor of the superconducting cable are connected in order to input and output power between the normal conducting conductor on the normal temperature side and the superconducting cable on the low temperature side. FIG. 9 is a schematic configuration diagram showing the entire terminal structure of the superconducting cable line of this example, and is a partial cross-sectional view. This terminal structure includes a connecting conductor 112, a conductor part 121, a refrigerant tank RC, a vacuum tank VC, a soot pipe 114, a conductor part 121 connected to the normal conducting conductor 111, and a superconducting conductor 102. Electrically connected.

  Hereinafter, each component will be described in detail.

  The superconducting cable of this example uses a single-phase superconducting cable 100 in which a single cable core 101 is housed in a heat insulating tube 103. Although not shown in the figure, the heat insulating tube 103 of the cable 100 has a structure in which a heat insulating material is disposed between a double tube composed of an outer tube and an inner tube, and the inside of the double tube is evacuated. The cable core 101 includes a former, a superconducting conductor, an electrical insulating layer, a shield layer, and a protective layer in order from the center. Note that a multiphase superconducting cable having a plurality of cable cores may be used as the superconducting cable.

  In this example, the end portion of the superconducting conductor 102 of the superconducting cable 100 is connected to the connecting conductor 112 via the connection sleeve S, and the connecting conductor 112 is further connected to the end portion of the conductor portion 121 via the joint portion 117. Thus, the normal conducting conductor 111 and the superconducting conductor 102 of the superconducting cable 100 are electrically connected. In this example, the connecting conductor 112 is made of a normal conducting material such as copper or aluminum, but may be made of a Bi2223 superconducting material.

  An epoxy unit 151 having an insulating function and mechanical strength is disposed on a part of the outer periphery of the connection conductor 112. The epoxy unit 151 has a flange 151f, and the connecting conductor 112 is fixed to a refrigerant tank RC described later by the flange 151f. An insulating material 152 such as kraft paper is disposed on both sides of the outer periphery of the connecting conductor 112 in the longitudinal direction of the epoxy unit 151 and on the outer periphery of the exposed superconducting conductor 102 of the cable core 101.

  A bushing 115 is disposed around the conductor portion 121 connected to the connection conductor 112. One end of the conductor portion 121 is disposed in the refrigerant tank RC, and passes through the refrigerant tank RC and the vacuum tank VC. The end is arranged so as to be inserted into the inside of the soot tube 114. The bushing 115 is configured by covering the outer periphery of a conductive metal cylinder with an insulating member such as FRP having excellent insulating properties. A space formed between the soot tube 114 and the bushing 115 is filled with an insulating fluid such as insulating oil.

  The conductors that are electrically connected as described above are cooled with a liquid refrigerant such as liquid nitrogen LN so as to maintain a superconducting state. Specifically, the joint portion 117 and the conductor portion 121 and a part of the connection conductor 112 in the vicinity of the joint portion 117 are arranged in the refrigerant tank RC and cooled with liquid nitrogen LN stored in the refrigerant tank RC. Is done. In addition, the sleeve S and the connection conductor 112 and a part of the superconducting conductor 102 in the vicinity of the sleeve S are disposed in the cable-side refrigerant tank 153 and cooled by the refrigerant stored in the tank 153.

  The refrigerant tank RC is made of stainless steel, and is formed by connecting a lower refrigerant tank container Rd having an L-shaped cross section and an upper refrigerant tank Ru having a U-shaped cross section (square bracket type). . The lower refrigerant tank container Rd has an insertion hole through which the connecting conductor 112 can be passed through the side wall (right side of the drawing), and is sealed by the flange 151f of the epoxy unit 151 described above. Further, the lid portion (upper side of the drawing) of the upper refrigerant tank container Ru has an insertion hole through which a bushing 115 covering the outer periphery of the conductor portion 121 can be penetrated, and this insertion hole is sealed with the bushing 115. ing.

  The connection between the upper refrigerant tank container Ru and the lower refrigerant tank container Rd is provided on the open end faces of both refrigerant tank containers Ru and Rd, similarly to the vacuum heat insulating container 2 of Example 2 already described with reference to FIG. This is done by connecting the flanges together. Of course, the flange is provided with a packing groove, and the gap between the flanges is sealed with the packing.

  Liquid nitrogen LN can be stored in the connected refrigerant tank RC, and the conductor disposed in the refrigerant tank RC can be cooled. A part of the liquid nitrogen LN stored in the refrigerant tank RC is vaporized to form a gas phase GN. The minimum operating liquid level of the liquid nitrogen LN was set to be higher than the upper end surface of the bellows 91. The minimum operating liquid level is the lowest height among the liquid levels of liquid nitrogen LN that fluctuate when operating the superconducting cable line.

  In addition, a reservoir 144, a pump 142, and a cooling device 141 provided outside the vacuum chamber VC are communicated with the refrigerant tank RC via a refrigerant supply passage 143. In this example, first, the refrigerant in the refrigerant tank RC is taken out of the vacuum tank VC by the pump 142 and temporarily stored in the reservoir 144, and the refrigerant is supplied from the reservoir 144 to the cooling device 141. Then, the refrigerant cooled by the cooling device 141 by the pump 142 is returned to the refrigerant tank RC so that the refrigerant in the refrigerant tank RC is circulated and cooled.

  On the outer periphery of the refrigerant tank RC, a vacuum heat insulating layer 30 that suppresses heat intrusion into the refrigerant tank RC from the outside of the terminal structure is formed. The vacuum heat insulating layer 30 is formed by covering the outer periphery of the refrigerant tank RC with the vacuum tank VC and evacuating the two tanks.

  The vacuum chamber VC is made of stainless steel, and is configured by connecting a lower vacuum chamber container Vd having an L-shaped section and an upper vacuum chamber container Vu having a square bracket type section. An insertion hole through which the cable side vacuum chamber 154 can be passed is provided on the side wall (right side of the drawing) of the lower vacuum chamber container Vd, and this insertion hole is sealed with the cable side vacuum chamber 154. In addition, an insertion hole through which a bushing 115 covering the outer periphery of the conductor portion 121 can be passed is provided in the lid portion (upper side of the drawing) of the upper vacuum chamber container Vu, and the insertion hole is sealed with the bushing 115. ing.

  The connection between the upper vacuum chamber container Vu and the lower vacuum chamber container Vd is similar to the vacuum heat insulating container 2 of Example 2 already described with reference to FIG. 3 between the flanges provided on the opening end faces of both vacuum chamber containers. Do by connection.

  The vacuum heat insulating layer 30 formed between the refrigerant tank RC and the vacuum tank VC described above is a bellows (partition) that connects the upper vacuum tank container Vu and the upper refrigerant tank container Ru, similarly to the vacuum heat insulating container of FIG. Part) 91 is divided into an upper heat insulating layer 30u and a lower heat insulating layer 30d.

  Note that the refrigerant tank, the vacuum tank, and the partition section may be configured as shown in FIGS. 1, 5, 6, 7, and 8.

  Similarly to the refrigerant tank RC and the vacuum tank VC described above, the cable-side refrigerant tank 153 and the cable-side vacuum tank 154 maintain the superconducting conductor 102 at the liquid nitrogen temperature.

According to the terminal structure of the superconducting cable line described above, the degree of vacuum of the lower heat insulating layer 30d that contributes to the cooling of the liquid refrigerant LN is unlikely to decrease (the pressure increases). Specifically, after construction of the terminal structure, even if the cable line is operated for several days to one week without additional evacuation, 10 ^-6 torr (1.33 × 10 ^-10 MPa) ) And the pressure of the lower heat insulating layer 30d was hardly changed. On the other hand, the pressure of the upper heat insulating layer 30u was 10 ⁻⁶ torr to 10 ⁻³ torr. The difference in the pressure of the heat insulating layer is that gas molecules released from the outer peripheral surface of the upper refrigerant tank container Ru to the upper heat insulating layer 30u are gas released from the outer peripheral surface of the lower refrigerant tank container Rd to the lower heat insulating layer 30d. This is due to more than molecules. That is, the container Rd is in contact with the liquid phase LN, whereas the container Ru is in contact with the gas phase GN, and the temperature of the container Ru is higher than the temperature of the container Rd. Note that the pressure inside the cable-side vacuum chamber 154 remained at 10 ⁻⁶ torr.

Here, in order to compare with the terminal structure of the present example, a test line was manufactured and operated with a conventional terminal structure in which the vacuum heat insulating layer was not divided into upper and lower parts. During operation, no additional evacuation was performed on the vacuum insulation layer. And the vacuum degree of the vacuum heat insulation layer fell significantly when the vacuum degree (evaluation criteria is a pressure) of the vacuum heat insulation layer of a terminal structure was measured several days-one week after the operation start. Specifically, the pressure of the vacuum insulation layer, which was 10 ^-6 torr when the terminal structure was constructed, is 10 ^-4 torr (1.33 × 10 ^-8 MPa). Is not sufficient, and there is a risk that the operation of the superconducting cable line may be hindered.

  According to the above comparison, according to the terminal structure of the superconducting cable line having the vacuum heat insulating structure of the present invention, the lowering of the vacuum degree of the upper heat insulating layer does not affect the vacuum degree of the lower heat insulating layer. The liquid refrigerant can be stably kept cold for a long period of time.

  Further, in the terminal structure of this example, the lower heat insulating layer 30d is also used during operation of the superconducting cable line by using the vacuum port 71 provided in the lower vacuum vessel Vd and the vacuum port 72 provided in the upper vacuum vessel Vu. And the upper heat insulating layer 30u can be evacuated independently. Therefore, only the upper heat insulating layer 30u whose degree of vacuum is likely to be reduced can be evacuated, and the operating cost can be reduced.

  Furthermore, since the cooling effect of the liquid refrigerant is high, the operation rate of the cooling device can be lowered, the flow rate of the refrigerant by the pump can be lowered, and the power consumption of the terminal structure can be achieved. In addition, when the flow rate decreases, the convection of the refrigerant in the refrigerant tank becomes gentle, so that the terminal structure with less electric field disturbance due to the circulation of the refrigerant and excellent insulation performance can be obtained.

  In addition, this invention is not limited to the structure of the Example mentioned above at all, and can be suitably changed in the range which does not deviate from the summary of this invention.

  The vacuum heat insulating container of the present invention can be suitably used to stably cool a liquid refrigerant over a long period of time. In particular, the vacuum heat insulating container of the present invention can be suitably used for the cooling of the liquid refrigerant in the terminal structure of the superconducting cable line.

1 is a longitudinal sectional view of a vacuum heat insulating container described in Example 1. FIG. 2 is a partial cross-sectional perspective view of each component of the vacuum heat insulating container described in Example 1. FIG. 3 is a longitudinal sectional view of a vacuum heat insulating container described in Example 2. FIG. It is a fragmentary sectional perspective view of the unit which formed the upper refrigerant tank container and the upper vacuum tank container integrally. It is a fragmentary sectional perspective view which shows another structure of the unit which integrally formed the upper refrigerant tank container and the upper vacuum tank container. It is a fragmentary sectional perspective view of the unit which formed the lower refrigerant tank container and the lower vacuum tank container integrally. 6 is a longitudinal sectional view of a vacuum heat insulating container described in Example 3. FIG. 6 is a longitudinal sectional view of a vacuum heat insulating container described in Example 4. FIG. 6 is a schematic configuration diagram of a terminal structure of a superconducting cable line described in Example 5. FIG. It is a fragmentary sectional view of the terminal structure of the conventional superconducting cable track.

Explanation of symbols

1,2,3,4 Vacuum insulated container Un1, Un2, Un3, Un4, Un5 unit
10 Refrigerant tank
10d Lower refrigerant tank container 10u Upper refrigerant tank container 10uu Upper refrigerant tank container
20 Vacuum chamber
20d Lower vacuum chamber 20u Upper vacuum chamber 20uu Upper vacuum chamber
11,12,13,14,15,21,22,23,24,25 Annular flange
30 Vacuum insulation layer 30d Lower insulation layer 30u Upper insulation layer
40 lid
51a, 51b.52a, 52b, 54a, 54b, 55a, 55b Annular packing
51ag, 51bg.52ag, 52bg, 54ag, 54bg Packing groove
61a, 61b, 62a, 62b, 63a, 63b, 65a, 65b Bolt hole
71,72 Vacuum port
81 Support member 82 Support rod 85 Adsorbent 86 Super insulation
90,92 Partition 91 Bellows
LN Liquid refrigerant (liquid phase) GN Gas phase
RC refrigerant tank Ru Upper refrigerant tank container Rd Lower refrigerant tank container
VC vacuum chamber Vu Upper vacuum chamber Vd Lower vacuum chamber
100 superconducting cable
101 Cable core 102 Superconducting conductor 103 Insulated pipe
111 Normal conducting conductor 112 Connecting conductor 114 Steel pipe 115 Bushing
117 Joint S Sleeve 121 Conductor
141 Cooling device 142 Pump 143 Refrigerant supply passage 144 Reservoir
151 Epoxy unit 151f Flange 152 Insulation material
153 Cable side refrigerant tank 154 Cable side vacuum tank
210 Connecting conductor 220 Normal conducting conductor 230 Refrigerant tank 240 Vacuum tank 250 Steel pipe
260 Bushing 270 Joint

Claims (6)

A vacuum insulation container comprising a refrigerant tank for storing a refrigerant composed of a liquid phase and a gas phase, and a vacuum tank covering the outer periphery of the refrigerant tank,
Have a corrugated plate-like partition portion for dividing the vacuum insulation layer on the upper insulation layer and the lower insulation layer formed between the coolant vessel and the vacuumed vessel,
The lower end of the connection point to the refrigerant tank in the partition is at a position below the liquid level when using the vacuum heat insulating container,
The vacuum heat insulating container , wherein the upper heat insulating layer mainly covers an outer peripheral surface of a portion of the refrigerant layer that contacts a gas phase portion of the refrigerant . The vacuum heat insulating container according to claim 1 , wherein an adsorbent that adsorbs gas molecules is disposed at least on the upper heat insulating layer side in the partition portion. The vacuum heat insulating container according to claim 1 or 2 , wherein a heat insulating material is disposed in the vicinity of at least one of the upper heat insulating layer side and the lower heat insulating layer side of the partition portion. The vacuum heat insulation container according to any one of claims 1 to 3 , wherein at least one of the refrigerant tank and the vacuum tank is configured by combining two or more divided pieces. Each of the refrigerant tank and the vacuum tank is configured by combining divided pieces that are divided into two or more in the vertical direction.
Before the vacuum insulated container assembled all the divided pieces, and the divided pieces of the split pieces and the vacuum chamber of the coolant vessel, any one of the preceding claims, characterized in that it is attached in advance partitioning portion The vacuum insulation container according to one item. Flanges for connecting the divided refrigerant vessel together or divided vacuum chamber with each other, and being provided on an end surface or a divided end face of the vacuum chamber was divided refrigerant tank according to claim 4 or 5. A vacuum insulation container according to 5 .

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