Low-temperature fluid transfer double pipe

Abstract

To downsize a thrust support structure used in a low-temperature fluid transfer pipe comprising a double structure, and facilitate its fitting work.SOLUTION: A double pipe (1) comprises an inner pipe (3) for passing a low-temperature fluid, and an outer pipe (5) covering the outside of the inner pipe, and forming a heat insulation layer (7) between itself and the inner pipe, and comprises a thrust support structure (9) between the inner pipe (3) and the outer pipe (5). The thrust support structure comprises: a first bearing member (11) fixed to an outer peripheral surface (3a) of the inner pipe (3), and comprising a first bearing surface (11a) facing a first direction (D1) along an axis (A) of the double pipe (1); a second bearing member (13) fixed to an inner peripheral surface (5a) of the outer pipe (5), and comprises a second bearing surface (13a) facing a second direction (D2) opposed to the first direction (D1); and a first intermediate bearing member (15) arranged between the first bearing surface (11a) of the first bearing member (11) and the second bearing surface (13a) of the second bearing member (13), and formed of a heat insulation material.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a double pipe used for transferring cryogenic fluids.

Background Art

[0002] In Patent Document 1, it has been proposed to use a double-structured vacuum-insulated pipe as a pipe for transferring cryogenic fluids such as liquefied gas. In a double pipe, a thrust is generated in the inner pipe through which the cryogenic fluid passes due to the pressure from the internal fluid. Conventionally, as one of the structures for suppressing the movement of the inner pipe due to such thrust, it has been considered to install a rod-shaped support member across between the outer pipe and the inner pipe to restrict the axial movement of the inner pipe with respect to the outer pipe.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventionally, as the material of the rod-shaped support member, the same metal material as the pipe has been used in order to firmly fix it to the inner pipe and the outer pipe. In that case, since the heat of the liquefied gas passing through the inner pipe is transmitted to the outer pipe through the metal support member, it is necessary to make the support member somewhat long to secure the heat transfer distance in order to suppress the heat transfer to the outer pipe. As a result, the required installation space is large, which also affects the layout of the pipe. In addition, since the rod-shaped support member is, for example, welded from the inner peripheral surface of the outer pipe to the outer peripheral surface of the inner pipe, it is necessary to weld this in a state where the outer pipe and the inner pipe are assembled, and the mounting work is complicated.

[0005] An object of the present disclosure is to miniaturize a thrust support structure used for a cryogenic fluid transfer pipe having a double structure and to facilitate its installation work in order to solve the above problems.

Means for Solving the Problems

[0006] In order to solve the above problems, a double pipe for cryogenic fluid transfer according to the present disclosure is an inner pipe through which a cryogenic fluid passes, an outer pipe that covers the outside of the inner pipe and forms a heat insulating layer between the inner pipe and the outer pipe, a double pipe comprising: a thrust support structure is provided between the inner pipe and the outer pipe, the thrust support structure includes a first pressure bearing member fixed to the outer peripheral surface of the inner pipe and having a first pressure bearing surface facing a first direction along the axis of the double pipe, a second pressure bearing member fixed to the inner peripheral surface of the outer pipe and having a second pressure bearing surface facing a second direction opposite to the first direction, a first intermediate pressure bearing member formed of a heat insulating material disposed between the first pressure bearing surface of the first pressure bearing member and the second pressure bearing surface of the second pressure bearing member, and comprises.

Effects of the Invention

[0007] According to the double pipe for cryogenic fluid transfer according to the present disclosure, the thrust support structure including the first pressure bearing member, the second pressure bearing member, and the first intermediate pressure bearing member can be made smaller than the conventional structure, and its installation work can be facilitated.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. FIG. 1 shows a double pipe 1 for transferring cryogenic fluid according to an embodiment of the present disclosure. In the following description, this double pipe 1 for transferring cryogenic fluid is simply referred to as "double pipe 1". The double pipe 1 of the present embodiment is configured as a vacuum-insulated pipe having a double structure. That is, the double pipe 1 is composed of an inner pipe 3 through which a cryogenic fluid passes and an outer pipe 5 that covers the outside of the inner pipe 3. The inner pipe 3 and the outer pipe 5 of the double pipe 1 are arranged concentrically, that is, so as to have the same axis C. A vacuum insulation layer 7 is formed in the radial gap between the inner pipe 3 and the outer pipe 5. However, the double pipe 1 does not have to be a vacuum-insulated pipe, and a heat insulating material may be provided in the space between the inner pipe 3 and the outer pipe 5 to form a heat insulating layer. In this specification, the axial direction, radial direction, and circumferential direction of the double pipe 1 are simply referred to as the "axial direction", "radial direction", and "circumferential direction", respectively. The inner pipe 3 and the outer pipe 5 are made of a metal material such as stainless steel. However, the materials of the inner pipe 3 and the outer pipe 5 are not limited to stainless steel.

[0010] The double pipe 1 is used, for example, in a liquefied gas storage facility such as a liquefied gas storage ship or an onshore liquefied gas storage base. In this specification, the "liquefied gas storage ship" refers to a ship having a function of storing liquefied gas. In addition to liquefied gas carriers, for example, liquefied gas fuel ships and bunkering ships that supply liquefied gas to other ships are included in the liquefied gas storage ships. However, the liquefied gas storage facility is not limited to a ship as long as it has a structure and function of storing liquefied gas, and may be, for example, an onshore liquefied gas storage facility or a plant that uses liquefied gas.

[0011] The cryogenic fluid transferred by the double pipe 1 is, for example, ammonia (LNH 3, approximately -30°C), liquefied petroleum gas (LPG, approximately -45°C), liquefied carbon dioxide (LCO 2 , approximately -80°C), liquefied ethylene gas (LEG, approximately -100°C), liquefied natural gas (LNG, approximately -160°C), liquefied nitrogen (LN 2 , approximately -200°C), liquefied hydrogen (LH 2 , approximately -250°C), liquefied helium (LHe, approximately -270°C), etc. In this embodiment, liquefied hydrogen is transferred through the double pipe 1. However, the cryogenic fluid referred to in this specification includes not only liquefied gas but also low-temperature vaporized gas generated from the liquefied gas. The double pipe 1 of the present disclosure can also be applied to facilities for transferring not only liquefied gas but also low-temperature vaporized gas.

[0012] In the inner pipe 3 through which such a cryogenic fluid passes, an axial thrust acts due to the pressure from the internal fluid.

[0013] Therefore, the double pipe 1 of this embodiment includes a thrust support structure 9 that supports the thrust acting in the axial direction on the inner pipe 3. The thrust support structure 9 includes a first pressure-bearing member 11, a second pressure-bearing member 13, and a first intermediate pressure-bearing member 15 disposed between these first and second pressure-bearing members 11 and 13. The thrust support structure 9 supports the thrust acting in one direction along the axis C of the double pipe 1. In this embodiment, the thrust support structure 9 supports the thrust acting in the first direction D1 along the axis C of the double pipe 1.

[0014] Specifically, in the present embodiment, as shown in FIG. 1, the first pressure supporting member 11 is fixed to the outer peripheral surface 3a of the inner pipe 3. The first pressure supporting member 11 has a first pressure supporting surface 11a facing a first direction D1 along the axis C of the double pipe 1. The second pressure supporting member 13 is fixed to the inner peripheral surface 5a of the outer pipe 5 and has a second pressure supporting surface 13a facing a second direction D2 opposite to the first direction D1. The first pressure supporting member 11 and the second pressure supporting member 13 are attached to the outer peripheral surface 3a of the inner pipe 3 and the inner peripheral surface 5a of the outer pipe 5 respectively, for example, by welding. The materials of the first pressure supporting member 11 and the second pressure supporting member 13 are the same as those of the double pipe 1 in order to firmly fix them to the inner pipe 3 and the outer pipe 5. However, the attachment methods and materials of the first pressure supporting member 11 and the second pressure supporting member 13 are not limited to these examples.

[0015] In the present embodiment, the first pressure supporting member 11 includes a first plate-like portion 11b and a first rib 11c that supports the first plate-like portion 11b. The first plate-like portion 11b extends radially from the outer peripheral surface 3a of the inner pipe 3 and has the first pressure supporting surface 11a. The first rib 11c is provided on the surface of the first plate-like portion 11b opposite to the first pressure supporting surface 11a. Similarly, the second pressure supporting member 13 includes a second plate-like portion 13b and a second rib 13c that supports the second plate-like portion 13b. The second plate-like portion 13b extends radially from the inner peripheral surface 5a of the outer pipe 5 and has the second pressure supporting surface 13a. The second rib 13c is provided on the surface of the second plate-like portion 13b opposite to the second pressure supporting surface 13a. The plate-like portions 11b, 13b and the ribs 11c, 13c of each pressure supporting member 11, 13 may be formed as integral parts, or may be parts formed separately and joined, for example, by welding. Further, the cross-sectional shape of each pressure supporting member 11, 13 along the axis C of the double pipe 1 is not limited to the trapezoid shown in the figure, and may be any shape such as a triangle or a quadrilateral.

[0016] The first support pressure member 11 and the second support pressure member 13 face each other with a radial gap with respect to the pipe surface on the side opposite to the fixed portion. That is, the first support pressure member 11 fixed to the inner pipe 3 faces the inner peripheral surface 5a of the outer pipe 5 with a radial gap therebetween, and the second support pressure member 13 fixed to the outer pipe 5 faces the outer peripheral surface 3a of the inner pipe 3 with a radial gap therebetween. This is because if these support pressure members 11 and 13 also contact the pipe surfaces on the opposite sides, heat transfer from the inner pipe 3 to the outer pipe 5 will occur. Since there is a gap in the radial direction, the inner pipe 3 and the outer pipe 5 made of metal do not come into contact with the support pressure members 13 and 11, preventing a decrease in heat insulation performance.

[0017] The first intermediate support pressure member 15 is disposed between the first support pressure surface 11a of the first support pressure member 11 and the second support pressure surface 13a of the second support pressure member 13. In the present embodiment, as shown in FIG. 2, when viewed in the axial direction, the first support pressure member 11 and the second support pressure member 13 overlap in the radial direction. Specifically, when viewed in the axial direction, the first plate-like portion 11b of the first support pressure member 11 and the second plate-like portion 13b of the second support pressure member 13 overlap in the radial direction. The first intermediate support pressure member 15 is disposed at the portion where the two support pressure members 11 and 13 overlap in the radial direction. By arranging the first support pressure member 11 and the second support pressure member 13 so as to have a radially overlapping portion in this way, the first intermediate support pressure member 15 can be disposed at the overlapping portion to reliably support the thrust acting on the inner pipe 3.

[0018] The first intermediate support pressure member 15 is formed of a heat insulating material. The first intermediate support pressure member 15 is preferably a heat insulating material made of, for example, glass fiber reinforced resin (GFRP). However, the heat insulating material forming the first intermediate support pressure member 15 is not limited to this example, and any high-strength heat insulating material that does not release gas under vacuum may be used. In addition to GFRP, for example, polyether ether ketone (PEEK) or the like can be used. The first intermediate support pressure member 15 is attached to either the first support pressure member 11 or the second support pressure member 13. The attachment of the first intermediate support pressure member 15 can be performed by any method, and for example, it can be fixed using bolts.

[0019] In this embodiment, the first intermediate pressure supporting member 15 is formed in a plate shape extending in the circumferential direction. In this embodiment, as shown in the longitudinal sectional view of FIG. 1, the first intermediate pressure supporting member 15 has a rectangular cross section and is not in contact with either the inner tube 3 or the outer tube 5. However, the first intermediate pressure supporting member 15 may be in contact with one or both of the inner tube 3 and the outer tube 5. In this case, the first intermediate pressure supporting member 15 can be given a function as a spacer for maintaining the interval between the inner tube 3 and the outer tube 5. Also, the first intermediate pressure supporting member 15 can have an arbitrary shape as long as it can receive a thrust between the first pressure supporting surface 11a of the first pressure supporting member and the second pressure supporting surface 13a of the second pressure supporting member 13.

[0020] The circumferential range where each of the pressure supporting members 11, 13, 15 constituting the thrust support structure 9 is provided may be appropriately set according to the thrust acting on the inner tube 3. In this embodiment, as shown in FIG. 2, each of the pressure supporting members 11, 13, 15 is provided at a plurality of locations in the circumferential direction, in this example, four locations, at equal intervals in the circumferential direction. However, the number of locations, the circumferential interval, and the shape of each of the pressure supporting members 11, 13, 15 can be arbitrarily determined and are not limited to those shown. For example, in this embodiment, each of the pressure supporting members 11, 13, 15 is fan-shaped when viewed in the axial direction as shown in FIG. 2, but can also have a shape having a curve along the pipe surface on one side of a quadrangle, for example. The first and second plate-like portions 11b, 13b of the first and second pressure supporting members 11, 13 of this embodiment extend over a part of the circumferential direction of the inner tube 3 and the outer tube 5, respectively. The first intermediate pressure supporting member 15 extends over the same circumferential range as each of the first and second plate-like portions 11b, 13b. Also, in this embodiment, each of the first and second plate-like portions 11b, 13b is supported by one rib 11c, 13c, respectively. However, a plurality of ribs may be provided on each of the plate-like portions 11b, 13b. The interval for providing the ribs 11c, 13c can be appropriately determined according to, for example, the required strength. It is not necessary to match the radial positions of the first rib 11c and the second rib 13c that support the first plate-like portion 11b and the second plate-like portion 13b, respectively.

[0021] By setting the circumferential range where the pressure-bearing members 11, 13, and 15 that constitute the thrust support structure 9 are arranged as a partial range in the circumferential direction in this way, the thrust support structure 9 can be installed at necessary locations according to the thrust acting on the inner pipe 3. As a result, the required materials are reduced, leading to cost reduction, and the degree of freedom in the piping layout can be increased.

[0022] However, the circumferential range where the pressure-bearing members 11, 13, and 15 that constitute the thrust support structure 9 are provided is not limited to this example. For example, the pressure-bearing members 11, 13, and 15 may be ring-shaped. According to this configuration, the thrust can be dispersed and received over a wide area, and a larger thrust can be supported. Furthermore, the circumferential ranges where the pressure-bearing members 11, 13, and 15 are provided do not necessarily have to completely coincide with each other.

[0023] According to the double pipe 1 according to the present embodiment, the thrust support structure 9 supports the thrust acting in the first direction D1 of the inner pipe 3. This thrust support structure 9 is composed of a first pressure-bearing member 11, a second pressure-bearing member 13, and a first intermediate pressure-bearing member 15 formed of a heat insulating material. Compared with the conventional structure that uses a long metal support member to secure the heat transfer distance, the thrust support structure can be miniaturized. Furthermore, compared with the conventional structure in which the support member is welded so as to span the inner pipe and the outer pipe, the first pressure-bearing member 11 and the second pressure-bearing member 13 are attached to the double pipe 1 at separate locations, and the first intermediate pressure-bearing member 15 is fixed to one of the pressure-bearing members, so that the installation work of the thrust support structure can be facilitated.

[0024] In the present embodiment, as shown in FIG. 1, the inner pipe 3 is provided with an expansion / contraction allowance portion 17 that absorbs changes in the axial length of the inner pipe 3. In the present embodiment, the inner pipe 3 has a bellows as the expansion / contraction allowance portion 17. Note that the expansion / contraction allowance portion 17 may be configured to allow, for example, displacement in the radial direction in addition to changes in the axial length of the inner pipe 3. According to this configuration, the thermal contraction of the inner pipe 3 can be absorbed.

[0025] In the present embodiment, as shown in FIG. 2, a thrust support structure 9 including a first pressing member 11, a second pressing member 13, and a first intermediate pressing member 15 has a communication gap G that allows the vacuum insulation layer 7 to communicate through the thrust support structure 9. The specific form of the communication gap G is not particularly limited. For example, when the first and second plate-like portions 11b and 13b and the first intermediate pressing member 15 exist only in a part of the circumferential direction as in the present embodiment, the communication gap G is formed by portions in the circumferential direction where the first and second plate-like portions 11b and 13b and the first intermediate pressing member 15 do not exist. As another exemplary form of the communication gap G, when the first and second plate-like portions 11b and 13b and the first intermediate pressing member 15 extend over the entire circumference and the first intermediate pressing member 15 is in contact with the inner pipe 3 and the outer pipe 5, the communication gap G can be provided as a hole penetrating them. When the first intermediate pressing member 15 is in contact with only one of the inner pipe 3 and the outer pipe 5, or when it is not in contact with either the inner pipe 3 or the outer pipe 5, a hole serving as the communication gap G can be provided in the plate-like portion on the side where the first intermediate pressing member 15 is not in contact with the inner pipe 3 and / or the outer pipe 5. By providing the communication gap G, when the heat insulation layer 7 is a vacuum insulation layer, the evacuation of the vacuum insulation layers 7 on both sides of the thrust support structure can be performed simultaneously using a common vacuum pump, and the management of the vacuum is also easy. However, it is not essential to provide the communication gap G.

[0026] In a modified example of the present embodiment, as shown in FIG. 3, a second thrust support structure 19 is provided on the double pipe 1. The second thrust support structure 19 includes a third pressing member 21, a fourth pressing member 23, and a second intermediate pressing member 25 disposed between these third and fourth pressing members 21 and 23. Similar to the above-described thrust support structure 9, the second thrust support structure 19 supports a thrust acting in one direction along the axis C of the double pipe 1. In the present embodiment, the second thrust support structure 19 supports a thrust acting in a second direction D2 along the axis C of the double pipe 1. By providing these thrust support structures 9 and 19, the thrusts acting in both directions D1 and D2 along the axis C of the double pipe 1 can be supported.

[0027] Specifically, in the modification shown in FIG. 3, the third pressing member 21 is fixed to the outer peripheral surface 3a of the inner pipe 3 and has a third pressing surface 21a facing the second direction D2. The fourth pressing member 23 is fixed to the inner peripheral surface 5a of the outer pipe 5 and has a fourth pressing surface 23a facing the first direction D1. Since the attachment methods and materials of the third pressing member 21 and the fourth pressing member 23 are the same as those of the first pressing member 11 and the second pressing member 13, the description thereof is omitted.

[0028] The second intermediate pressing member 25 is disposed between the third pressing surface 21a of the third pressing member 21 and the fourth pressing surface 23a of the fourth pressing member 23 and is formed of a heat insulating material. Since the attachment method, material, and shape of the second intermediate pressing member 25 are the same as those of the first intermediate pressing member 15, the description thereof is omitted.

[0029] By providing the thrust support structures 9 and 19, in addition to supporting the thrust acting on the double pipe 1 in the first direction D1 by the thrust support structure 9, it is also possible to support the thrust such as seismic force acting in the second direction D2 by the thrust support structure 19.

[0030] In a further modification of the present embodiment, as shown in FIG. 4, a thrust support structure 29 is provided on the double pipe 1. Briefly, the thrust support structure 29 is a structure in which the first pressing member 11 and the third pressing member 21 of the above-described thrust support structures 9 and 19 are integrated. Specifically, the thrust support structure 29 includes a second pressing member 13, a first intermediate pressing member 15, a shared intermediate pressing member 31, a second intermediate pressing member 25, and a fourth pressing member 23. The second pressing member 13 and the fourth pressing member 23 are fixed to the inner peripheral surface 5a of the outer pipe 5, and the shared intermediate pressing member 31 is fixed to the outer peripheral surface 3a of the inner pipe 3. The first intermediate pressing member 15 is disposed between the second pressing member 13 and the shared intermediate pressing member 31, and the second intermediate pressing member 25 is disposed between the shared intermediate pressing member 31 and the fourth pressing member 23. Also in this case, it is possible to support the thrust acting in both directions along the axis C of the double pipe 1. Further, since the number of parts is smaller than in the case of the modification shown in FIG. 3, the burden of the attachment work of the thrust support structure is reduced.

[0031] In the illustrated example, the common intermediate pressure supporting member 31 is fixed to the outer peripheral surface 3a of the inner pipe 3. However, the common intermediate pressure supporting member 31 may be fixed to the inner peripheral surface 5a of the outer pipe 5, and the pressure supporting members on both sides may be fixed to the outer peripheral surface 3a of the inner pipe 3. The common intermediate pressure supporting member 31 may extend over the entire circumference or a part of the outer peripheral surface 3a of the inner pipe 3 or the inner peripheral surface 5a of the outer pipe 5.

[0032] In FIG. 4, the common intermediate pressure supporting member 31 is a member including common intermediate plate-like portions 31b, 31b on both sides and a common intermediate rib 31c provided therebetween. However, the common intermediate pressure supporting member 31 is not limited to the illustrated example. For example, the common intermediate plate-like portions 31b, 31b and the common intermediate rib 31c may be integrally formed, or it may be a ring-shaped member having a rectangular cross section. Also in this modified example, the communication gap G can be appropriately provided as a circumferential gap or a through hole according to the circumferential range and shape of the second plate-like portion 13b, the fourth plate-like portion 23b, and the common intermediate pressure supporting member 31.

[0033] In the modified example shown in FIG. 4, the common intermediate pressure supporting member 31 is fixed, for example, by welding and is made of the same material as the double pipe 1, similar to the first pressure supporting member 11 and the third pressure supporting member 21. Although not shown, instead of forming the common intermediate pressure supporting member 31 from the common intermediate plate-like portions 31b, 31b and the common intermediate rib 31c, the common intermediate pressure supporting member 31 may be a ring-shaped member having a rectangular cross section composed of a base fixed to the outer peripheral surface 3a of the inner pipe 3 and a heat insulating material fixed to the outer pipe side portion of the base, and the heat insulating material of the ring-shaped member may be sandwiched between the first intermediate pressure supporting member 15 and the second intermediate pressure supporting member 25. In this case, since the number of metal members constituting the thrust support structure is reduced, heat transfer between cold and heat can be further suppressed, and the heat insulating performance of the double pipe 1 can be improved. Also, if necessary, by setting the dimension of the heat insulating material on the inner pipe side to be in contact with the outer peripheral surface of the outer pipe 5, the radial movement of the inner pipe 3 can be restricted.

[0034] Although detailed description is omitted, the double pipe 1 according to the present embodiment may include structural elements other than the illustrated elements, such as a spacer that restricts the radial relative movement between the inner pipe 3 and the outer pipe 5, and an expansion allowance portion provided on the outer pipe, as necessary.

[0035] The double pipe 1 according to the first aspect of the present embodiment described above includes an inner pipe 3 through which a low-temperature fluid shown in FIG. 1 passes, and an outer pipe 5 that covers the outside of the inner pipe 3 and forms a heat insulation layer 7 between the inner pipe 3 and the outer pipe 5. The double pipe 1 is provided with a thrust support structure 9 between the inner pipe 3 and the outer pipe 5. The thrust support structure 9 includes a first pressure support member 11 fixed to the outer peripheral surface 3a of the inner pipe 3 and having a first pressure support surface 11a facing a first direction D1 along the axis C of the double pipe 1, and a second pressure support member 13 fixed to the inner peripheral surface 5a of the outer pipe 5 and having a second pressure support surface 13a facing a second direction D2 opposite to the first direction D1. The thrust support structure 9 further includes a first intermediate pressure support member 15 formed of a heat insulating material and disposed between the first pressure support surface 11a of the first pressure support member 11 and the second pressure support surface 13a of the second pressure support member 13. According to this configuration, the thrust support structure 9 including the first pressure support member 11, the second pressure support member 13, and the first intermediate pressure support member 15 can be made smaller than the conventional structure, and the mounting work thereof can be facilitated.

[0036] The double pipe 1 according to the second aspect of the present embodiment may include an expansion allowance portion 17 that absorbs a change in the length of the inner pipe 3 in the axial direction of the inner pipe 3 in the double pipe according to the first aspect. According to this configuration, the thermal contraction of the inner pipe 3 can be absorbed.

[0037] The double pipe 1 according to the third aspect of the present embodiment is the double pipe according to the first or second aspect, in which the thrust support structure 19 shown in FIG. 3 is fixed to the outer peripheral surface 3a of the inner pipe 3, and has a third pressure receiving surface 21a facing the second direction D2. A third pressure receiving member 21, a fourth pressure receiving member 23 fixed to the inner peripheral surface 5a of the outer pipe 5 and having a fourth pressure receiving surface 23a facing the first direction D1, and the third pressure receiving surface 21a of the third pressure receiving member 21, and the fourth pressure receiving surface 23a of the fourth pressure receiving member 23, and a second intermediate pressure receiving member 25 formed of a heat insulating material disposed therebetween. According to this configuration, in addition to supporting the thrust acting on the double pipe 1 in the first direction D1 by the thrust support structure 9, the thrust such as seismic force acting in the second direction D2 can also be supported by the thrust support structure 19.

[0038] The double pipe 1 according to the fourth aspect of the present embodiment is the double pipe according to the third aspect, in which the first pressure receiving member 11 and the third pressure receiving member 21 of the thrust support structure 9 may be integrally formed to constitute a shared intermediate pressure receiving member 31. According to this configuration, since the number of parts is reduced, the burden of the mounting work of the thrust support structure is reduced.

[0039] The double pipe 1 according to the fifth aspect of the present embodiment is the double pipe according to any one of the first to third aspects, and when viewed in the axial direction, the first pressure receiving member 11 shown in FIG. 2 and the second pressure receiving member 13 may overlap in the radial direction. According to this configuration, by arranging the first pressure receiving member 11 and the second pressure receiving member 13 so as to have an overlapping portion in the radial direction, the first intermediate pressure receiving member 15 is arranged in the overlapping portion, and the thrust acting on the inner pipe 3 can be reliably supported.

[0040] The double pipe 1 according to the sixth aspect of the present embodiment is a double pipe according to any one of the first to fourth aspects, and the thrust support structure 9 including the first pressure support member 11, the second pressure support member 13, and the first intermediate pressure support member 15 may have a communication gap G that communicates the heat insulation layer 7 through the thrust support structure 9. According to this configuration, when the heat insulation layer 7 is a vacuum heat insulation layer, the evacuation of the vacuum heat insulation layer 7 on both sides of the thrust support structure can be performed simultaneously using a common vacuum pump, and the management of the vacuum is also easy.

[0041] As described above, the preferred embodiments of the present disclosure have been described with reference to the drawings. However, various additions, changes, or deletions are possible without departing from the spirit of the present disclosure. Therefore, such things are also included within the scope of the present disclosure.

Explanation of Reference Numerals

[0042] 1 Double pipe 3 Inner pipe 3a Outer peripheral surface of the inner pipe 5 Outer pipe 5a Inner peripheral surface of the outer pipe 7 Heat insulation layer 9, 19, 29 Thrust support structure 11 First pressure support member 11a First pressure support surface 11b First plate-like portion 11c First rib 13 Second pressure support member 13a Second pressure support surface 13b Second plate-like portion 13c Second rib 15 First intermediate pressure support member 17 Expansion and contraction allowance portion 21 Third pressure support member 21a Third pressure support surface 23 Fourth pressure support member 23a Fourth pressure support surface 25 Second intermediate pressure support member 31 Common intermediate pressure support member 31b, 31b Common intermediate plate-like portion 31c Common intermediate rib C Axis of the double pipe D1 First direction D2 Second direction G Communication gap

Claims

1. An inner pipe through which a cryogenic fluid passes, an outer pipe that covers the outside of the inner pipe and forms a heat insulation layer between the inner pipe and the outer pipe, a double pipe comprising: a thrust support structure is provided between the inner pipe and the outer pipe, the thrust support structure includes: a first pressure-bearing member fixed to the outer peripheral surface of the inner pipe and having a first pressure-bearing surface facing a first direction along the axis of the double pipe; a second pressure-bearing member fixed to the inner peripheral surface of the outer pipe and having a second pressure-bearing surface facing a second direction opposite to the first direction; a first intermediate pressure-bearing member formed of a heat insulating material and disposed between the first pressure-bearing surface of the first pressure-bearing member and the second pressure-bearing surface of the second pressure-bearing member; A double pipe for transferring cryogenic fluid, comprising:

2. In the double pipe according to claim 1, the inner pipe is provided with an expansion allowance portion that absorbs a change in the length of the inner pipe in the axial direction thereof, A double pipe for transferring cryogenic fluid.

3. In the double pipe according to claim 1 or 2, the thrust support structure includes: a third pressure-bearing member fixed to the outer peripheral surface of the inner pipe and having a third pressure-bearing surface facing the second direction; a fourth pressure-bearing member fixed to the inner peripheral surface of the outer pipe and having a fourth pressure-bearing surface facing the first direction; a second intermediate pressure-bearing member formed of a heat insulating material and disposed between the third pressure-bearing surface of the third pressure-bearing member and the fourth pressure-bearing surface of the fourth pressure-bearing member; Comprising: A double pipe for transferring cryogenic fluid.

4. In the double pipe according to claim 3, the first pressure-bearing member and the third pressure-bearing member of the thrust support structure are integrally formed to constitute a shared intermediate pressure-bearing member, A double pipe for transferring cryogenic fluid.

5. In the double pipe according to claim 1 or 2, when viewed in the axial direction, the first pressure-bearing member and the second pressure-bearing member overlap in the radial direction, A double pipe for transferring cryogenic fluid.

6. In the double pipe according to claim 1 or 2, the thrust support structure has a communication gap for communicating the heat insulation layer through the thrust support structure, A double pipe for transferring cryogenic fluid.

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