Piping unit for conveying extremely low-temperature fluid

Abstract

A piping unit (1) for conveying an extremely low temperature fluid is provided with: a double piping (3) having an inner pipe (15) through which an extremely low temperature fluid passes, and an outer pipe (17) covering the outer side of the inner pipe (15) and forming a first vacuum insulation layer (19) between the outer pipe (17) and the inner pipe (15); a single pipe (5) separated from the double pipe (3); and a shut-off valve (7) connecting the dual piping (3) and the single piping (5), in which a cover (11) is provided that covers a portion of the single piping (5) exposed from a valve box (9) of the shut-off valve (7) and forms a second vacuum heat-insulating layer (21) between the cover (11) and the single piping (5).

Description

Technical Field

[0001] The present disclosure relates to a piping unit for conveying cryogenic fluids. Background Art

[0002] Conventionally, a scheme using a double-structured vacuum insulated pipe has been proposed as a pipe for transporting liquefied gas such as liquefied natural gas and liquefied hydrogen (for example, see Patent Document 1). The double-structured pipe has a structure in which an outer pipe covers an inner pipe via a heat insulation layer, thereby achieving high heat insulation and effectively suppressing the temperature rise of the low-temperature liquefied gas flowing in the inner pipe.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2022-101284 Summary of the invention

[0006] Problems to be solved by the invention

[0007] Usually, in liquefied gas equipment, the piping for transporting extremely low-temperature liquefied gas uses a double-structured piping, while the piping for not allowing extremely low-temperature liquefied gas to flow uses a single-structured piping. A stop valve that cuts off the flow of liquefied gas is installed at the connection between these double piping and the single piping. In this case, due to the heat transfer from the liquefied gas in the double piping, the single piping part is also cryogenically cooled via the stop valve. As a result, liquid oxygen may be generated around the cryogenically cooled single piping, so this situation needs to be prevented.

[0008] In order to solve the above-mentioned problems, the present disclosure aims to prevent the generation of liquid oxygen around a pipe with a simple structure in a single-structure gas transport pipe connected to a double-structure cryogenic fluid transport pipe via a stop valve.

[0009] Means for solving problems

[0010] In order to achieve the above-mentioned purpose, the piping unit for transporting ultra-low temperature fluid of the present invention comprises: a double piping having an inner tube and an outer tube, the inner tube allowing the ultra-low temperature fluid to pass through, the outer tube covering the outer side of the inner tube, and forming a first vacuum insulation layer between the outer tube and the inner tube; a single piping connected to one end of the inner tube; a stop valve installed between the double piping and the single piping, and the stop valve is connected to the double piping on its primary side and to the single piping on its secondary side; and a cover covering the portion of the single piping exposed from the valve box of the stop valve to form a second vacuum insulation layer between the cover and the single piping.

[0011] Any combination of at least two structures disclosed in the claims and / or the specification and / or the drawings is also included in the present disclosure. In particular, any combination of two or more of each claim of the claims is also included in the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present disclosure is more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and the accompanying drawings are for illustration and description only and should not be used to determine the scope of the present disclosure. The scope of the present disclosure is determined by the appended claims. In the accompanying drawings, the same reference numerals in multiple drawings represent the same or equivalent parts.

[0013] Figure 1 This is a longitudinal sectional view showing a schematic structure of a cryogenic fluid transport piping unit according to an embodiment of the present disclosure.

[0014] Figure 2A It is shown in Figure 1 A longitudinal sectional view showing a schematic structure of a modified example in which the cover has a different shape in the embodiment.

[0015] Figure 2B It is shown in Figure 1 A longitudinal sectional view showing a schematic structure of another modified example in which the cover has a different shape in the embodiment.

[0016] Figure 3 It is shown in Figure 1 A longitudinal sectional view showing a schematic structure of a cover expansion and contraction allowing portion provided on a cover in a cryogenic fluid transport piping unit according to a modified example of the embodiment.

[0017] Figure 4 Yes Figure 1 A longitudinal sectional view showing an example of the shape of a cover used in another modification of the embodiment of the invention in an enlarged manner.

[0018] Figure 5 It is shown Figure 1 A longitudinal sectional view showing a schematic structure of a cryogenic fluid transport piping unit according to another modified example of the embodiment.

[0019] Figure 6 It is shown Figure 1 A longitudinal sectional view showing a schematic structure of a cryogenic fluid transport piping unit according to another modified example of the embodiment. DETAILED DESCRIPTION

[0020] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Figure 1A piping unit 1 for transporting a cryogenic fluid according to an embodiment of the present invention is shown. Hereinafter, the piping unit 1 for transporting a cryogenic fluid is referred to as a "piping unit 1". The piping unit 1 is suitable for connecting a double piping and a single piping using a vacuum insulation structure. The piping unit 1 includes a double piping 3, a single piping 5 separated from the double piping 3, a stop valve 7 connecting the double piping 3 and the single piping 5, and a cover 11 covering a portion of the single piping 5 exposed from a valve box 9 of the stop valve 7.

[0021] The piping unit 1 is used in, for example, liquefied gas storage equipment such as a liquefied gas storage ship or a liquefied gas storage base on land. In this specification, a "liquefied gas storage ship" refers to a ship having a function of storing liquefied gas. In addition to liquefied gas transport ships, liquefied gas fuel ships, fuel ships that supply liquefied gas to other ships, etc. are also included in liquefied gas storage ships. However, liquefied gas storage equipment is not limited to ships as long as it has a structure and function to store liquefied gas. For example, it can also be liquefied gas storage equipment on land or equipment that uses liquefied gas.

[0022] like Figure 1 As shown, the double pipe 3 is constituted as a vacuum insulation pipe having a double structure. That is, the double pipe 3 is constituted by an inner pipe 15 for passing a cryogenic fluid and an outer pipe 17 covering the outer side of the inner pipe 15. A first vacuum insulation layer 19 is formed in the radial gap between the inner pipe 15 and the outer pipe 17.

[0023] The cryogenic fluid transported by the double piping 3 is, for example, liquefied gas such as liquefied nitrogen (LN2, about -200°C), liquefied hydrogen (LH2, about -250°C), and liquefied helium (LHe, about -270°C). In the present embodiment, liquefied hydrogen is transported via the double piping 3. However, the cryogenic fluid referred to in this specification includes not only liquefied gas, but also cryogenic gas generated from liquefied gas. The piping unit 1 disclosed in the present invention can be applied not only to equipment for transporting liquefied gas, but also to equipment for transporting cryogenic gas.

[0024] The single-weight pipe 5 is connected to one end of the inner tube 15. The single-weight pipe 5 is, for example, a pipe for conveying a relatively high-temperature fluid to such an extent that liquid oxygen is not generated on the pipe surface. A stop valve 7 is interposed between the double pipe 3 and the single-weight pipe 5. In a typical operation of the piping unit 1 in which an extremely low-temperature fluid is caused to flow from the double pipe 3 side to the single-weight pipe 5 side, the double pipe 3 is connected to the primary side of the stop valve 7, and the single-weight pipe 5 is connected to the secondary side. In addition, in the piping unit 1, there may be a situation in which an operation different from the typical operation is performed in which an extremely low-temperature fluid is caused to flow from the single-weight pipe 5 side to the double pipe 3 side. However, in the following description, for convenience, the side of the stop valve 7 connected to the double pipe 3 is referred to as the primary side, and the side connected to the single-weight pipe 5 is referred to as the secondary side.

[0025] Specifically, the double piping 3 and the single piping 5 are connected to the valve box 9 of the shut-off valve 7. The valve box 9 is joined to the double piping 3 and the single piping 5 by welding. However, the joining method between the valve box 9 and the piping 3, 5 is not limited to welding, and any method such as flange connection and threaded connection can be used. A valve body for cutting off or adjusting the flow rate, a valve shaft for operating the valve body, etc. are arranged inside the valve box 9. The shut-off valve 7 is cut off in such a way that the extremely low temperature fluid flowing in the double piping 3 does not flow into the single piping 5 side. In the present embodiment, a glasses valve is used as the shut-off valve 7, but any type of valve may be used as needed.

[0026] Since the primary side of the stop valve 7 is in contact with the cryogenic fluid in the double pipe 3, the stop valve 7 and the portion around the stop valve 7 in the single pipe 5 on its secondary side are cryogenically cooled by transferring cold energy from the cryogenic fluid. Here, "cryogenic cooling" of the pipe surface means that the temperature of the pipe surface becomes extremely low. When the pipe surface is cryogenically cooled, liquid oxygen may be generated when the pipe is exposed to the outside air. For example, the generation of liquid oxygen may occur on the pipe surface below -183°C.

[0027] In the present embodiment, a cover 11 is provided to cover the portion of the single-weight pipe 5 exposed from the valve box 9 of the stop valve 7 and to form a second vacuum insulation layer 21 between the single-weight pipe 5 and the cover 11. On the secondary side of the stop valve 7, a second vacuum insulation layer 21 is also formed between the single-weight pipe 5 and the cover 11. Specifically, the stop valve 7 of the present embodiment has a vacuum jacket 23 covering the valve box 9, and the cover 11 is formed by a single-weight pipe side end 23a of the vacuum jacket 23 and a cylindrical member 25 connected to the single-weight pipe side end 23a. That is, in this example, one end of the vacuum jacket 23 on the single-weight pipe 5 side extends in the axial direction beyond the valve box 9 to the single-weight pipe side, and the cover 11 is formed by a portion of the vacuum jacket 23 extending beyond the valve box 9, namely the single-weight pipe side end 23a and the cylindrical member 25.

[0028] In this way, by covering the portion of the single-weight pipe 5 from the valve box of the stop valve 7 to a predetermined length with the cover 11, it is possible to prevent the deep-cooled portion of the single-weight pipe from being exposed to the outside air. In addition, by setting the space between the single-weight pipe 5 and the cover 11 as the vacuum insulation layer 21, it is possible to prevent heat transfer from the single-weight pipe 5 to the cover 11, thereby preventing the cover 11 from being deep-cooled. Thus, it is possible to prevent the generation of liquid oxygen on the side of the single-weight pipe 5.

[0029] The cylindrical component 25 constituting the cover 11 can be configured as a single tube arranged on the outside of the single-weight distribution pipe 5, for example. When the cylindrical component 25 is configured as a single tube, for example, the cylindrical component 25 can be formed as a single tube having the same material and / or diameter as the outer tube 17 of the double-weight distribution pipe 3. The end of the cylindrical component 25 on the opposite side of the stop valve 7 is closed by a cover 25a. In the illustrated example, the cylindrical component 25 has a roughly cylindrical shape. In addition, the cylindrical component 25 can be composed of a plurality of, for example, two divided cylinders, or can be composed of more than three divided cylinders. In addition, the shape of the cylindrical component 25 is not limited to a cylindrical shape, and can also be other cylindrical shapes such as a square cylinder shape.

[0030] In this specification, the "cover 11" refers to an element that covers the single-weight pipe 5 regardless of its form, Figure 1 Regardless of the specific form of the vacuum jacket 23 and / or the positional relationship between the vacuum jacket 23 and the tubular member 25, the portion of the single-weight pipe 5 exposed from the valve box 9 of the stop valve 7 is covered as described above to form a second vacuum insulation layer 21 between the single-weight pipe 5 and the single-weight pipe 5. As described above, Figure 1 In the embodiment shown, the cover 11 is formed by the single-weight pipe side end 23a of the vacuum jacket 23 and the tubular member 25. In this example, the end of the tubular member 25 opposite to the stop valve 7 is closed by a cover 25a.

[0031] As a variation of this embodiment, for example, Figure 2A As shown in FIG. 1 , when the single-weight distribution pipe side end portion 23a of the vacuum jacket 23 is extended longer, in other words, when the vacuum jacket 23 and the Figure 1 When the cylindrical member 25 is integrally formed, the cover 11 is formed by Figure 2A The end portion 23a of the single-weight pipe side end portion 23a on the opposite side of the stop valve 7 is closed by the cover portion 23b of the vacuum jacket 23. Figure 2B As another modified example, when the tubular member 25 is provided so as to also cover the end portion 23 a of the vacuum jacket 23 on the single-weight pipe side, the covering portion 25 b of the tubular member 25 covering the exposed portion of the single-weight pipe 5 becomes the cover 11 .

[0032] exist Figure 1In the present embodiment shown, the first vacuum insulation layer 19 is connected to the second vacuum insulation layer 21. Specifically, the first vacuum insulation layer 19 and the second vacuum insulation layer 21 are connected via the space between the valve box 9 of the stop valve 7 and the vacuum jacket 23. If a partition is provided between these vacuum insulation layers 19 and 12, the partition is deep-cooled due to the heat transfer of the extremely low temperature fluid from the primary side of the stop valve 7, and as a result, the surface of the cover 11 connected to the partition may be deep-cooled. Therefore, by adopting a structure in which the first vacuum insulation layer 19 and the second vacuum insulation layer 21 are connected, deep cooling of the cover 11 can be suppressed. In addition, the first vacuum insulation layer 19 and the second vacuum insulation layer 21 can be vacuum-exhausted simultaneously using a common vacuum pump, and vacuum management is also easy. However, the first vacuum insulation layer 19 and the second vacuum insulation layer 21 do not necessarily have to be connected.

[0033] In this embodiment, if Figure 1 As shown, the axial length L1 of the cover 11 is longer than the length L2 from the axial position P of the fluid communication cut-off portion on the double piping side in the stop valve 7 to the axial end 9a on the single piping 5 side of the valve box 9. In this specification, the "fluid communication cut-off portion" may vary depending on the specific structure of the stop valve 7, but for example, in the case of the above-mentioned glasses valve, it becomes the downstream end of the primary side flow path in the state where the valve body is closed. It should be noted that in the example shown in the figure, the above-mentioned axial position P indicates the approximately central position in the axial direction of the valve box 9, but it can be a different position depending on the specific structure of the stop valve 7. The axial length L1 of the cover 11 can be, for example, 250 mm or more. By setting it as such a structure, the cover 11 can cover the portion of the single piping 5 that is sufficiently away from the above-mentioned position P that becomes the starting point of deep cooling, and can more reliably prevent the generation of liquid oxygen caused by deep cooling of the piping surface. However, the axial length L1 of the cover 11 is not limited to this example.

[0034] In the piping unit 1 of this embodiment, Figure 1 As shown, the single-weight pipe 5 has a pipe expansion and contraction allowing portion 31 that allows changes in the axial length in the portion covered by the cover 11. In the present embodiment, the single-weight pipe 5 has a bellows as the pipe expansion and contraction allowing portion 31. In addition, the pipe expansion and contraction allowing portion 31 may also be configured to allow, for example, radial displacement in addition to allowing changes in the axial length of the single-weight pipe 5. According to this structure, it is possible to suppress the generation of high stress in the connection portion between the single-weight pipe 5 and the cover 11, and to suppress deformation and breakage. Furthermore, by providing a pipe expansion and contraction allowing portion 31 such as a bellows, the heat transfer distance of the inner pipe 5 in the cover 11 is increased, so that the transfer of cold energy to the outside of the cover 11 can be more effectively suppressed.

[0035] Of course, the expansion and contraction allowance portion that allows the change in the axial length can be provided in at least one of the cover 11 and the portion of the single pipe 5 covered by the cover 11. In a modified example of the present embodiment, the pipe unit 1 Figure 3 As shown, the cover 11 may also have a cover expansion and contraction allowing portion 33 that allows changes in the axial length. In this modified example, the cover 11 has a bellows as the cover expansion and contraction allowing portion 33. Similar to the piping expansion and contraction allowing portion 31, the cover expansion and contraction allowing portion 33 may also be constructed to allow, for example, radial displacement in addition to allowing changes in the axial length of the cover 11. The cover expansion and contraction allowing portion 33 is effective in allowing thermal contraction of the inner tube 15 and absorbing the thermal contraction difference between the inner tube and the outer tube. According to this structure, it is possible to suppress the generation of high stress in the connecting portion between the single-weight piping 5 and the cover 11, and it is possible to suppress deformation and breakage. If such an expansion and contraction allowing portion is provided on the cover 11, it is easier to inspect than if it is provided on the single-weight piping 5 covered by the cover 11.

[0036] In the above description, an example in which the single-weight pipe 5 has the pipe expansion and contraction allowing portion 31 and an example in which the cover 11 has the cover expansion and contraction allowing portion 33 are separately shown, but both the pipe expansion and contraction allowing portion 31 and the cover expansion and contraction allowing portion 33 may be provided in the pipe unit 1. In addition, both the pipe expansion and contraction allowing portion 31 and the cover expansion and contraction allowing portion 33 may be omitted.

[0037] like Figure 4 As another modified example, the shape of the cover 11 may also have a curved shape of the cover portion 25a on the opposite side of the valve box 9. Specifically, in the example shown in the figure, the cover portion 25a is curved in a manner that smoothly decreases in diameter from the peripheral wall of the cover 11 toward the single-weight distribution pipe 5. By setting the cover portion 25a of the cover 11 to such a shape, it is possible to alleviate stress concentration applied to the connection portion between the single-weight distribution pipe 5 and the cover 11 due to, for example, expansion and contraction of the single-weight distribution pipe 5. In addition, in Figure 3 In the figure, it is shown that Figure 1 The piping unit 1 shown is an example in which the cover portion 25a of the hood 11 is set to the above-mentioned curved shape instead of providing the piping expansion and contraction allowing portion 31. However, in addition to providing either or both of the piping expansion and contraction allowing portion 31 and the hood expansion and contraction allowing portion 33, the cover portion 25a of the hood 11 may also be set to the above-mentioned curved shape.

[0038] In this embodiment, if Figure 1As shown in FIG. 1 , the piping unit 1 includes a temperature measuring device 35 for measuring the temperature of the single-weight pipe 5. The temperature measuring device 35 includes a temperature sensor element 35a for detecting the temperature of the detection object, and the temperature sensor element 35a is arranged at the end 5a of the portion covered by the cover 11 of the single-weight pipe 5. According to this structure, by measuring the temperature of the single-weight pipe 5 at the end 5a closest to the portion not covered by the cover 11 among the portions covered by the cover 11 in the single-weight pipe 5, it is possible to reliably grasp that the portion not covered by the cover 11 is not cryogenically cooled. However, it is not necessary to provide the temperature measuring device 35 in the piping unit 1.

[0039] In addition, in addition to the temperature sensor element 35a, the temperature measuring device 35 may also have various circuits for performing necessary processing such as signal conversion processing and calculation processing on the obtained detection quantity, a memory for storing information required for these processes, a power supply element such as a battery or a power supply circuit for receiving power supply from the outside, a transmission circuit for sending output signals to the outside in a wired or wireless manner, etc. at an appropriate location.

[0040] In the piping unit 1 of another modified example of the present embodiment, Figure 5 As shown, an additional stop valve 37 may be provided at the portion of the single-weight pipe 5 exposed from the cover 11. By providing the additional stop valve 37 downstream of the stop valve 7 in the flow direction of the cryogenic fluid, the flow of the cryogenic fluid can be more reliably shut off.

[0041] In the piping unit 1 of another modified example of the present embodiment, Figure 6 As shown, the portion of the single-weight pipe 5 exposed from the cover 11 may also be covered by the heat-insulating material 39. With such a configuration, when the extremely low-temperature fluid is temporarily allowed to flow from the double-weight pipe 5 to the single-weight pipe 5, the single-weight pipe 5 can be properly insulated. The range covered by the heat-insulating material 39 can be arbitrarily determined according to the temperature of the pipe surface, etc. In addition, as the heat-insulating material 39, for example, a vacuum insulation panel can be used. The heat-insulating material 39 may also be a powder instead of a panel-shaped component. The raw material used as the heat-insulating material 39 is not particularly limited, and may be, for example, an organic polymer material such as polyurethane foam and polyethylene foam, or an inorganic material such as pearlite.

[0042] in addition, Figure 5 The additional stop valve 37 and Figure 6 The heat insulating material 39 shown can be arbitrarily combined with the structure of any of the above-mentioned modified examples.

[0043] In addition to the above-described configuration, various valves and measuring devices may be provided as necessary in the piping unit 1. For example, a vacuum gauge may be provided at any location communicating with the second vacuum insulation layer 21 formed by the cover 11.

[0044] In this embodiment, as described above, the piping unit 1 is used for transporting liquefied hydrogen. The temperature of liquefied hydrogen is lower than that of liquid oxygen, so the advantage of applying the above-mentioned piping unit 1 is great. However, as described above, the piping unit 1 of this embodiment can be used for transporting other than liquefied hydrogen.

[0045] The piping unit 1 of the first mode of the present embodiment described above comprises: a double piping 3 having an inner pipe 15 and an outer pipe 17, the inner pipe 15 allowing a cryogenic fluid to pass therethrough, the outer pipe 17 covering the outer side of the inner pipe 15, and forming a first vacuum insulation layer 19 between the outer pipe 17 and the inner pipe 15; a single piping 5 which is separate from the double piping 3; a shutoff valve 7 connecting the double piping 3 and the single piping 5; and a cover 11 which covers a portion of the single piping 5 exposed from a valve box 9 of the shutoff valve 7 and forms a second vacuum insulation layer 21 between the cover 11 and the single piping 5. According to this structure, the cover 11 covers a portion of the single piping 5 from the valve box of the shutoff valve 7 to a predetermined length, thereby preventing the deep-cooled portion of the single piping from being exposed to the outside air. Furthermore, by forming the space between the single-weight pipe 5 and the cover 11 as the vacuum insulation layer 21, heat transfer from the single-weight pipe 5 to the cover 11 can be suppressed, thereby preventing the cover 11 from being cryogenically cooled. Thus, generation of liquid oxygen on the single-weight pipe 5 side can be prevented.

[0046] The piping unit 1 of the second mode of the present embodiment may be such that, in the piping unit of the first mode, the first vacuum insulation layer 19 is connected to the second vacuum insulation layer 21. According to this structure, deep cooling of the secondary side of the shutoff valve 7 can be suppressed, and the first vacuum insulation layer 19 and the second vacuum insulation layer 21 can be vacuum-exhausted using a common vacuum pump, and vacuum management is also easy.

[0047] The piping unit 1 of the third aspect of the present embodiment may be such that, in the piping unit of the first or second aspect, the axial length L1 of the cover 11 is longer than the length L2 from the axial position P of the fluid communication cutoff portion on the double piping 3 side in the stop valve 7 to the axial end 9a on the single piping 5 side of the valve box 9. According to this structure, the cover 11 can cover the portion of the single piping 5 that is sufficiently away from the position P that becomes the starting point of deep cooling, and the generation of liquid oxygen caused by deep cooling of the piping surface can be more reliably prevented.

[0048] The piping unit 1 of the fourth mode of the present embodiment may be a piping unit of any of the first to third modes, wherein at least one of the cover 11 and the portion of the single-weight pipe 5 covered by the cover 11 has a telescopic allowance portion that allows a change in the axial length, namely, the cover telescopic allowance portion 33 and / or the piping telescopic allowance portion 31. According to this structure, it is possible to suppress the generation of high stress in the connection portion between the single-weight pipe 5 and the cover 11, and to suppress deformation and breakage. In addition, when the piping telescopic allowance portion 31 is provided, since the heat transfer distance in the single-weight pipe 5 is increased, it is possible to more effectively suppress the transfer of cold energy to the outside of the cover 11.

[0049] The piping unit 1 of the fifth aspect of the present embodiment may be the piping unit of any of the first to fourth aspects, wherein an additional shutoff valve 37 is provided at a portion of the single pipe 5 exposed from the cover 11. This configuration can more reliably shut off the flow of the cryogenic fluid.

[0050] The piping unit 1 of the sixth aspect of the present embodiment may be the piping unit of any of the first to fifth aspects, wherein a temperature sensor element 35a for detecting the temperature of the single-weight pipe 5 is disposed at the end of the portion of the single-weight pipe 5 covered by the cover 11. According to this configuration, by measuring the temperature of the single-weight pipe 5 at the end 5a closest to the portion not covered by the cover 11 among the portions of the single-weight pipe 5 covered by the cover 11, it is possible to reliably grasp that the portion not covered by the cover 11 is not cryogenically cooled.

[0051] As described above, the preferred embodiments of the present disclosure have been described with reference to the drawings, but various additions, changes, or deletions may be made without departing from the gist of the present disclosure. Therefore, such configurations are also included in the scope of the present disclosure.

[0052] Description of symbols

[0053] 1: Piping unit for transporting extremely low temperature fluid; 3: Double piping; 5: Single piping; 5a: End of single piping; 7: Stop valve; 9: Valve box; 11: Cover; 15: Inner pipe; 17: Outer pipe; 19: First vacuum insulation layer; 21: Second vacuum insulation layer; 23: Vacuum jacket; 23a: End of single piping side; 23b: Cover of vacuum jacket; 25: Cylindrical component; 25a: Cover of cylindrical component; 25b: Covering part; 31: Piping expansion and contraction allowance part (expansion and contraction allowance part); 33: Cover expansion and contraction allowance part (expansion and contraction allowance part); 35: Temperature measuring device; 35a: Temperature sensor element; 37: Additional stop valve; 39: Insulation material; L1: Axial length of the cover; L2: Dimension of the single piping side of the valve box; P: Fluid connection cut-off part on the double piping side of the stop valve.

Claims

1. A piping unit for transporting a cryogenic fluid, comprising: A double pipe having an inner pipe and an outer pipe, wherein the inner pipe allows a cryogenic fluid to pass through, and the outer pipe covers the outer side of the inner pipe, and a first vacuum insulation layer is formed between the outer pipe and the inner pipe; a single-pipe, which is separate from the double-pipe; a stop valve connecting the double pipe and the single pipe; and A cover covers a portion of the single-weight pipe exposed from the valve box of the shutoff valve to form a second vacuum insulation layer between the cover and the single-weight pipe.

2. The cryogenic fluid transport piping unit according to claim 1, wherein: The first vacuum heat insulating layer and the second vacuum heat insulating layer are in communication with each other.

3. The cryogenic fluid transport piping unit according to claim 1 or 2, wherein: The axial length of the cover is longer than the length from the axial position of the fluid communication cutoff portion on the double pipe side of the shutoff valve to the axial end of the valve box on the single pipe side.

4. The cryogenic fluid transport piping unit according to claim 1 or 2, wherein: At least one of the cover and a portion of the single-weight pipe covered by the cover has an expansion and contraction allowance portion that allows a length change in the axial direction.

5. The cryogenic fluid transport piping unit according to claim 1 or 2, wherein: An additional shutoff valve is provided at a portion of the single-weight pipe exposed from the cover.

6. The cryogenic fluid transport piping unit according to claim 1 or 2, wherein: A temperature sensor element for detecting the temperature of the single-weight pipe is disposed at an end portion of the portion of the single-weight pipe covered by the cover.

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