JP2016080053A - Joint structure of vacuum insulated double pipe for cryogenic fluid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joint structure for cryogenic fluid vacuum heat insulation double pipe that can be connected easily within a short time and even if the joint structure is damaged, it can be recovered within a short time.SOLUTION: A joint structure 10 of a cryogenic fluid vacuum heat insulation double pipe comprises inner pipes 2a, 2b and outer pipes 3a, 3b outwardly fitted with vacuum layers 4a, 4b being spaced apart between the inner pipes 2a, 2b. Each of the connected end side prescribed length portions of the pair of vacuum heat insulation double pipes 1a, 1b is formed with inner pipe expanded diameter parts 7a, 7b in stepped manner through the annular walls 6a, 6b. The inner peripheral sides of the pair of inner pipe expanded diameter parts are provided with inner cylindrical members for joint 9 for vacuum heat insulation double pipe structure having the same inner diameter as that of the inner pipes, the inner cylindrical members for joint are arranged under no-contact in respect to the pair of inner pipe expanded diameter parts and the inner pipes, a pair of joint flanges 13a, 13b arranged at end parts of the pair of vacuum heat insulation double pipe are fastened with a plurality of bolts and nuts.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a joint structure of a vacuum insulated double pipe for a cryogenic fluid.

  Conventionally, in piping for transporting low-temperature fluids such as various low-temperature liquefied gas, in order to ensure heat insulation performance, an inner tube and an outer tube fitted with a cylindrical vacuum layer on the inner tube The vacuum heat insulation double pipe comprised by these is well-known. When low-temperature liquefied gas (for example, liquefied helium, liquefied hydrogen, liquefied nitrogen, liquefied oxygen, etc.) is allowed to flow inside the inner tube, a vacuum layer is formed between the inner tube and the outer tube to prevent convective heat transfer. A vacuum heat insulating double tube utilizing the heat insulating effect of the vacuum layer is put into practical use.

  As a joint structure for connecting the vacuum heat insulating double pipe and the vacuum heat insulating double pipe, a bayonet joint is widely used in practical use. In the bayonet joint described in Patent Document 1, a male-side joint portion having a small diameter is formed by a male-side inner tube and an outer tube, and the inside is made into a vacuum layer, and a female-side inner tube and an outer tube The female joint is inserted into the male joint, and the inside is made into a vacuum layer. The joint flange is provided on the diameter-reduced part of the outer pipe of the male joint, and the joint is attached to the end of the female joint. By providing a flange, inserting the male joint part into the female joint part with a minute cylindrical gap and fastening a pair of joint flanges with a plurality of bolts and nuts, the bayonet joint is brought into a connected state.

JP 2010-169185 A

  Under circumstances where the working environment is unstable, the male side joint part of the bayonet joint may frequently be inserted with an inclination with respect to the female side joint part. The outer pipe of the male joint part comes into contact, but since the joint flange of the female joint part is a bulk body and has higher rigidity than the male joint part, the male joint part having low rigidity is damaged. Once the male joint is damaged, the internal vacuum is broken, so it is necessary to replace the pipes to which the male joint is connected in addition to the male joint, and to evacuate the internal. The repair took a long time.

  The objective of this invention is providing the joint structure of the vacuum heat insulation double pipe | tube for low temperature fluids which has a low failure risk, ensuring the heat insulation characteristic comparable as a bayonet joint.

  The joint structure of a vacuum insulated double pipe for cryogenic fluid according to claim 1 comprises an inner pipe and a vacuum insulated double pipe for cryogenic fluid having an outer pipe fitted with a vacuum layer between the inner pipe and the outer pipe. In each of the joint structures, an inner pipe diameter-enlarged portion is formed by enlarging the inner pipe in each of the predetermined length portions on the connection end side of the pair of vacuum heat insulating double pipes. An inner tube member for a joint having a vacuum heat insulation double tube structure having the same inner diameter as the inner tube is provided on the inner peripheral side, and a plurality of pairs of fastening portions provided at ends of a pair of vacuum heat insulation double tubes are fastened. It is characterized by being fastened by a member.

  The joint structure of a vacuum insulated double pipe for low-temperature fluid according to claim 2 is characterized in that, in the invention according to claim 1, a filter member that traps foreign matter in the low-temperature fluid is mounted inside the inner cylinder member for joint. It is said.

  The joint structure of the vacuum insulated double pipe for cryogenic fluid according to claim 3 is the invention according to claim 2, wherein the filter member is formed in a convex cup shape on the downstream side in the flow direction of the cryogenic fluid, The outer peripheral end portion on the upstream side in the flow direction of the low-temperature fluid is fixed to the inner peripheral surface of the joint inner cylinder member.

  The joint structure of a vacuum insulated double pipe for cryogenic fluid according to claim 4 comprises an inner pipe and a vacuum insulated double pipe for cryogenic fluid having an outer pipe fitted with a vacuum layer between the inner pipe and the outer pipe. In the joint structure, an outer tube reduced diameter portion obtained by reducing the diameter of the outer tube is formed in each of the predetermined length portions of the connection end side of the pair of vacuum heat insulating double tubes, and the outer tube and the outer tube reduced diameter portion are formed. A pair of joint flanges joined are provided, and on the outer peripheral side of the pair of outer pipe diameter-reduced portions, a joint outer cylinder member having a vacuum heat insulation double pipe structure in which joint flange portions are provided at both ends is provided, The pair of joint flanges are fastened to corresponding joint flange portions of the joint outer cylinder member by a plurality of fastening members, respectively, and the joint outer cylinder member includes a plurality of divided outer cylinder members, The outer cylinder member is connected by fastening each set of connection flanges with a plurality of fastening members. To have.

  According to the first aspect of the present invention, the inner pipe expanded portion is formed in each of the predetermined length portions of the connection end side of the pair of vacuum heat insulating double tubes, and the inner circumference of the pair of inner tube expanded portions. Since the inner cylinder member for joints with a vacuum heat insulation double pipe structure is provided on the side, when connecting the joint structure, a part of the inner cylinder member for fittings is attached to the inner diameter of the inner diameter of one vacuum heat insulation double pipe In this state, it is possible to connect by fitting the inner pipe expanded portion of the other vacuum heat insulating double pipe to the remaining portion of the joint inner cylinder member.

  In this connection, even if the vacuum heat insulating double pipe is tilted and fitted to the joint inner cylinder part, and the fastening part of the inner pipe expanded part comes into contact with the joint inner cylinder member, the rigid fastening part is damaged. Without this, the joint inner cylinder member will be damaged. Thus, even if the inner cylinder member for joints is damaged, it can be connected using an alternative inner cylinder member for joints prepared in advance. In addition, a large heat transfer distance from the inner tube that contacts the low-temperature fluid to the fastening portion can be secured via a pair of inner tube diameter-expanded portions and the inner tube member for joints, ensuring the same heat insulation characteristics as the bayonet joint. it can.

  According to the second aspect of the present invention, foreign matters (solid nitrogen pieces or the like) in the low-temperature fluid can be captured by the filter member mounted inside the inner cylinder member for joint.

  According to the invention of claim 3, since the filter member is formed in a convex cup shape on the downstream side in the flow direction of the cryogenic fluid, the filter member is captured and held while securing a passage area through which the cryogenic fluid flows. be able to. Since the outer peripheral end of the filter member on the upstream side in the flow direction of the low-temperature fluid is fixed to the inner peripheral surface of the joint inner cylinder member, the filter member is separated together with the joint inner cylinder member by separating the joint structure. Easy to attach and detach.

  According to the invention of claim 4, the outer tube diameter-reduced portion is formed in each of the predetermined length portions of the connection end side of the pair of vacuum heat insulating double tubes, and the pair of outer tube diameter-reduced portions are abutted against each other. After being in a state, a plurality of divided outer cylinder members are attached to the outer peripheral side of the outer pipe diameter-reduced parts to form an outer cylinder member for joints, and the joint flange part of the outer cylinder member for joints is a joint on the vacuum heat insulating double pipe side A plurality of fastening members are fastened to the flange, and each set of connecting flanges of the plurality of split outer cylinder members is fastened by a plurality of fastening members.

  Therefore, when connecting the joint structure of a vacuum insulated double pipe for low-temperature fluid, the joint structure can be connected without performing the work of inserting the cylindrical member into the opposite cylindrical portion. There is no possibility of damaging the members constituting the.

In addition, the heat transfer distance from the inner pipe that contacts the low temperature fluid to the joint flange via the outer pipe diameter-reduced portion can be increased, and the same heat insulating property as that of the bayonet joint can be secured.

It is sectional drawing of the joint structure of the vacuum heat insulation double pipe | tube for cryogenic fluids concerning Example 1 of this invention. It is the A section enlarged view of FIG. It is sectional drawing of the joint structure of the vacuum heat insulation double tube for cryogenic fluids concerning Example 2. FIG. It is the IV-IV sectional view taken on the line of FIG. It is the B section enlarged view of FIG. It is sectional drawing of the joint structure of the vacuum heat insulation double tube for cryogenic fluids concerning Example 3. FIG. It is the VII-VII sectional view taken on the line of FIG. It is sectional drawing of the joint structure of the vacuum heat insulation double pipe | tube for low temperature fluids which concerns on Example 4. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1 and FIG. 2, the vacuum heat insulating double tube 1 for cryogenic fluid is used for transporting a cryogenic fluid such as liquefied gas (liquefied helium, liquefied hydrogen, liquefied nitrogen, liquefied oxygen, etc.) which is a cryogenic fluid. It is a heavy pipe. A pair of vacuum heat insulating double pipes 1a and 1b connected through the joint structure 10 of the present application are fitted to the inner pipes 2a and 2b and concentrically with a space in the inner pipes 2a and 2b. The outer tubes 3a and 3b, and the vacuum layers 4a and 4b formed in the cylindrical space between the inner tubes 2a and 2b and the outer tubes 3a and 3b. Internal passages 5a and 5b for transporting liquefied gas are formed inside the inner pipes 2a and 2b. Although not shown, a super insulation for blocking radiant heat is wound around the outer circumference of the inner pipes 2a and 2b.

  The inner pipes 2a and 2b are made of stainless steel or aluminum alloy, and the outer pipes 3a and 3b are made of ordinary steel or stainless steel, and the outer diameters and plate thicknesses of the inner pipes 2a and 2b and the outer pipes 3a and 3b. Is appropriately set according to the use of the vacuum heat insulating double tube 1.

Next, the joint structure 10 in which the ends of the vacuum heat insulating double pipes 1a and 1b for low-temperature fluid are flange-connected through the joint flanges 13a and 13b will be described.
Inner pipes in which the inner pipes 2a and 2b are stepped in diameters through the annular wall portions 6a and 6b to the connection end side predetermined (set) length portions of the pair of vacuum heat insulating double pipes 1a and 1b, respectively. Expanded diameter portions 7a and 7b are formed. The annular wall portions 6a and 6b are arranged orthogonal to the axis X of the double tubes 1a and 1b, the inner peripheral ends thereof are joined to the end portions of the inner tubes 2a and 2b, and the outer peripheral ends thereof are the corresponding inner tubes. It is joined to the end portions (end portions on the corresponding inner pipes 2a, 2b side) of the enlarged diameter portions 7a, 7b.

A cylindrical housing space 8 is formed on the inner peripheral side of the pair of inner tube enlarged portions 7a, 7b by the pair of annular wall portions 6a, 6b and the pair of inner tube enlarged portions 7a, 7b. Yes. The dimension in the radial direction on one side of the accommodation space 8 is, for example, about 8 to 16 mm, but is not limited to this value.
The length of the housing space 8 in the axial center X direction is a predetermined length (for example, 200 to 200) that can secure a necessary heat transfer distance between the annular wall portions 6a and 6b on one side and the enlarged diameter portions 7a and 7b on the inner side. 300 mm). However, it is not limited to this value.

  In the housing space 8, a joint inner cylinder member 9 having a vacuum heat insulation double pipe structure having the same inner diameter as the inner pipes 2a and 2b is disposed, and this joint inner cylinder member 9 has a pair of inner pipe diameter expansions. The portions 7a and 7b and the pair of annular wall portions 6a and 6b are disposed in a non-contact manner. A small cylindrical gap 8a is formed between the outer peripheral surface of the joint inner cylinder member 9 and the pair of inner pipe enlarged diameter portions 7a, 7b.

  The joint inner cylinder member 9 includes an inner cylinder 9a having the same diameter as the inner tubes 2a and 2b, an outer cylinder 9b concentrically fitted to the inner cylinder 9a, and the inner cylinder 9a and the outer cylinder. And a cylindrical vacuum layer 9c formed between the body 9b. The thickness of the vacuum layer 9c is, for example, about 4 to 10 mm, but is not limited to this value. The inner cylinder 9a and the outer cylinder 9b are made of the same material as the inner tubes 2a and 2b. Although not shown in the figure, a super insulation for blocking radiant heat is wound around the outer peripheral surface of the joint inner cylinder member 9.

At both ends, an annular seal member 11 made of, for example, PTFE (tetrafluoroethylene) having a heat insulating function is attached and fixed between the end of the inner cylinder 9a and the end of the outer cylinder 9b. Has been. In addition, a pair of annular seal members 12 that seals between the both ends of the joint inner cylinder member 9 and the pair of annular wall portions 6a and 6b at both ends of the housing space 8 are made of, for example, PTFE. A seal member 12 is mounted and fixed to the annular wall portions 6a and 6b.
The annular heat insulating members 11 and 12 may be composed of a synthetic rubber gasket or the like. Further, a pair of annular spacers may be mounted between the both end portions of the outer cylinder member 9b and the inner pipe enlarged diameter portions 7a and 7b.

  An annular joint flange 13a is joined to the end of the vacuum heat insulating double pipe 1a so as to be orthogonal to the axis X, and an annular joint flange 13b is orthogonal to the axis X of the end of the vacuum heat insulating double pipe 1b. The joint flanges 13a and 13b (each of which corresponds to a fastening portion) are brought into contact with each other in a surface contact state and fastened by a plurality of bolts 14a and nuts 14b (fastening members). A gasket 15 is mounted in an annular seal groove formed at the inner peripheral portion of one joint flange 13b.

  The operation and effect of the joint structure 10 of the vacuum heat insulating double pipe for cryogenic fluid described above will be described. Inner pipe diameter-expanded portions 7a and 7b are formed in the connection end side predetermined length portions of the pair of vacuum heat insulating double pipes 1a and 1b, and the inner circumferences of the pair of inner pipe diameter-expanded portions 7a and 7b. Since the inner tube member 9 for a joint having a vacuum heat insulating double pipe structure is provided in a non-contact manner on the inner pipe enlarged diameter portions 7a, 7b and the annular wall portions 6a, 6b on the side, With the left half of the inner cylinder member 9 attached to the inner pipe expanded portion 7a of one vacuum heat insulating double pipe 1a, the right half of the inner cylinder member 9 for joint is the inner pipe of the other vacuum heat insulating double pipe 1b. It can connect by inserting in the enlarged diameter part 7b.

In this case, since the insertion length for inserting the joint inner cylinder member 9 into the other vacuum heat insulating double pipe 1b is shortened, the insertability is improved and the joint structure 10 can be easily connected.
In addition, even if the joint inner cylinder member 9 is damaged, it can be connected by using the alternative joint inner cylinder member 9 prepared in advance. There is no delay. In addition, the inner pipe diameter-expanded portions 7a and 7b that do not come into contact with the low-temperature fluid through the joint inner cylinder member 9 and the seal member 12 can secure a large heat transfer distance, so that the same heat insulating property as that of the bayonet joint is secured. be able to.

  The plate thicknesses of the inner cylinder body 9a and the outer cylinder body 9b of the joint inner cylinder member 9 are desirably set to be thinner than the plate thicknesses of the outer tubes 3a and 3b. If set in this way, the inner cylinder member 9 can be reliably broken when the fitting state of the joint structure 10 is poor, so that damage to the vacuum heat insulating double pipes 1a and 1b can be prevented.

  As shown in FIGS. 3 to 5, the vacuum heat insulation double tube 1 </ b> A for cryogenic fluid is used for transporting a cryogenic fluid such as liquefied gas (liquefied helium, liquefied hydrogen, liquefied nitrogen, liquefied oxygen, etc.) that is a cryogenic fluid. It is a heavy pipe. A pair of vacuum heat insulating double pipes 1a and 1b connected via the joint structure 10A of the present application are fitted to the inner pipes 2a and 2b and concentrically with a space in the inner pipes 2a and 2b. The outer tubes 3a and 3b, and the vacuum layers 4a and 4b formed in the cylindrical space between the inner tubes 2a and 2b and the outer tubes 3a and 3b. Internal passages 5a and 5b for transporting liquefied gas are formed inside the inner pipes 2a and 2b. Although not shown, a super insulation for blocking radiant heat is wound around the outer circumference of the inner pipes 2a and 2b.

  The inner pipes 2a and 2b are made of stainless steel or aluminum alloy, and the outer pipes 3a and 3b are made of ordinary steel or stainless steel, and the outer diameters and plate thicknesses of the inner pipes 2a and 2b and the outer pipes 3a and 3b. Is appropriately set according to the use of the vacuum heat insulating double pipe 1A.

Next, the joint structure 10A in which the ends of the vacuum heat insulating double pipes 1a and 1b for low-temperature fluid are flange-connected through joint flanges will be described.
Thin vacuum layers 41a and 41b are formed on the outer peripheral sides of the inner pipes 2a and 2b in the predetermined length portions of the connection end side of the pair of vacuum heat insulating double pipes 1a and 1b, respectively, and the reduced diameter outer pipes 30a and 30b are removed. The outer pipe diameter-reduced portions 32a and 32b are formed, and annular joint flanges 31a and 31b joined to the outer pipes 3a and 3b and the reduced-diameter outer pipes 30a and 30b are provided. The joint flanges 31a and 31b are arranged orthogonal to the axis X of the vacuum heat insulating double tubes 1a and 1b.

  A cylindrical outer peripheral space 24 is formed on the outer peripheral side of the pair of outer tube diameter-reduced portions 32a and 32b, and the radial dimension on one side of the outer peripheral space 24 is, for example, 20 to 40 mm. The length in the center X direction is, for example, 200 to 300 mm. The thickness of the vacuum layers 41a and 41b is, for example, about 4 to 10 mm. However, the above numerical values are examples, and are not limited to these numerical values.

  At the distal end portions of the pair of outer tube diameter-reduced portions 32a and 32b, heat insulating seal members 25a and 25b made of PTFE are attached and fixed between the inner tubes 2a and 2b and the reduced-diameter outer tubes 30a and 30b. For joints having a vacuum heat insulation double pipe structure having the same outer diameter as the outer pipes 3a and 3b on the outer peripheral side of the pair of outer pipe reduced diameter parts 32a and 32b and having joint flange parts 26a and 26b at both ends. An outer cylinder member 27 is provided. A minute gap 24a is formed between the pair of outer pipe reduced diameter portions 32a and 32b and the joint outer cylinder member 27, and the joint outer cylinder member 27 is connected to the pair of outer pipe reduced diameter portions 32a and 32b. In contrast, they are arranged in a non-contact manner.

  The joint outer cylinder member 27 includes an inner cylinder 27a made of the same material as the inner pipes 2a and 2b, an outer cylinder 27b made of the same material as the outer pipes 3a and 3b, and joint flanges 26a and 26b joined to both ends. And. A vacuum layer 27 c is formed between the inner cylinder 27 a and the outer cylinder 27 b of the joint outer cylinder member 27. The joint flanges 31a and 31b at the ends of the pair of vacuum heat insulating double tubes 1a and 1b are respectively connected to the corresponding joint flange portions 26a and 26b of the joint outer cylinder member 27 by a plurality of bolts 28a and nuts 28b (fastening members). It is concluded. Gaskets 33a and 33b are mounted in seal grooves formed in the inner peripheral portions of the joint flanges 31a and 31b.

  However, as shown in FIG. 4, the joint outer cylinder member 27 of the present embodiment is a pair of symmetrical split outer cylinders divided by a split surface D including the axis X of the vacuum heat insulating double pipes 1a and 1b. Consists of members 27U and 27L, and a pair of split outer cylinder members 27U and 27L are fastened with a plurality of bolts 30a and nuts 30b (fastening members) for each set of connection flanges 29 and 29 located on both sides of the split surface D. It is connected by doing. Therefore, the inner cylindrical body 27a is composed of a pair of semi-cylindrical members, and the outer cylindrical body 27b is composed of a pair of semi-cylindrical members. The pair of joint flange portions 26a and 26b are also divided at the dividing surface. A seal member 29a is mounted in a linear seal groove formed in one of the pair of connecting flanges 29, 29 that are vertically opposed to each other.

  When connecting the vacuum heat insulating double pipes 1a and 1b, the axial centers X of the double pipes 1a and 1b are aligned and the tips of the outer pipe reduced diameter portions 32a and 32b are brought into contact with each other. A pair of split outer cylinder members 27U and 27L that constitute the joint outer cylinder member 27 are arranged to face each other, and two sets of connection flanges 29 and 29 are fastened by a plurality of bolts 30a and nuts 30b (fastening members). The joint flange portion 26a is fastened to the joint flange 31a of the vacuum heat insulating double pipe 1a by a plurality of bolts 28a and nuts 28b (fastening members), and a plurality of joint flange portions 26b are attached to the joint flange 31b of the vacuum heat insulating double pipe 1b. The bolt 28a and the nut 28b (fastening member) are used for fastening. In addition, although the outer cylinder member 27 for a joint of the present Example was made into the 2 division structure, you may make it the structure divided not only into 2 divisions but into 3 divisions.

  The operation and effect of the joint structure 10A for the vacuum heat insulating double pipe for cryogenic fluid described above will be described. Since the joint outer cylinder member 27 is composed of a pair of symmetrical split outer cylinder members 27U and 27L divided by the dividing plane D, a pair of double inner pipes are connected when connecting the joint structure 10A. Since the joint outer cylinder member 27 can be mounted by mounting the pair of split outer cylinder members 27U and 27L on the outer peripheral side in a state where the portions 22a and 22b are butted, the connection of the joint structure 10A can be performed. It can be done easily in a short time.

  When connecting the joint structure 10A, it is not necessary to insert the cylindrical member into the cylindrical portion, so that the connection work of the joint structure 10A can be performed easily and efficiently, and there is no possibility of damaging the cylindrical member or the like. . However, even if the joint outer cylinder member 27 is damaged, it can be connected by using an alternative joint outer cylinder member 27 prepared in advance. There is no delay.

The joint structure 10B of the vacuum heat insulating double pipe 1B for low temperature fluid, which is a partial modification of the joint structure 10A of the vacuum heat insulating double pipe for low temperature fluid of the second embodiment, will be described. The same reference numerals are given to the same components as those of the joint structure 10A, and description thereof will be omitted.
In the present embodiment, the joint outer cylinder member 27B is formed as an annular integral member.
One outer tube diameter-reduced portion 32bB is formed in a tapered shape (partial conical shape) so that the diameter of the outer diameter-reduced outer tube 30bB becomes smaller toward the tip side, and the outer tube of the inner cylinder body 27aB of the outer cylinder member 27B for joints. The right half portion corresponding to the reduced diameter portion 30bB is formed in a tapered shape (partial conical shape) like the reduced diameter outer tube 30bB. An annular vacuum layer 41bB is formed in the outer tube diameter-reduced portion 32bB. A vacuum layer 27cB is formed inside the joint outer cylinder member 27B.

  When connecting the joint structure 10B, the joint outer cylinder member 27B is fitted on the outer pipe reduced diameter portion 22a on the double pipe 1a side, and the joint flange 31a and the joint flange portion 26a are fastened. The outer tube reduced diameter portion 32bB on the double tube 1b side is inserted into the joint outer cylinder member 27B, and the joint flange 31b and the joint flange portion 26bB are fastened by a plurality of bolts 28a and nuts 28b (fastening members).

The operation and effect of the joint structure 10B of the vacuum heat insulating double pipe for low temperature fluid will be described.
With the left half of the joint outer cylinder member 27B fitted on the outer pipe reduced diameter part 32a of one vacuum heat insulating double pipe 1a, the outer pipe reduced diameter part 32bB of the other vacuum heat insulating double pipe 1b is used for the joint. The joint structure 10B can be connected by being inserted into the outer cylinder member 27B. In this case, since the inner diameter of the right half part of the joint outer cylinder member 27B is formed in a tapered shape so as to increase toward the double pipe 1b, the other outer pipe reduced diameter part 32bB is formed on the joint outer cylinder member 27B. Since the insertion length for inserting the joint becomes shorter, the insertability is improved, and the joint structure 10B can be easily connected in a short time.

  In addition, even if the joint outer cylinder member 27B is damaged, it can be connected by using the previously prepared alternative joint outer cylinder member 27B. There is no delay. In addition, since a large heat transfer distance can be ensured through the outer tube diameter-reduced portions 32a and 32bB, it is possible to ensure heat insulation characteristics equivalent to the bayonet joint.

A description will be given of a joint structure 10C for a vacuum-insulated double pipe for low-temperature fluid according to a fourth embodiment in which the first embodiment is partially changed. In addition, the same code | symbol is attached | subjected to the same component as the component of Example 1, those description is abbreviate | omitted, and only a different structure is demonstrated.
A filter member 50 that captures foreign matter in the low-temperature fluid is mounted inside the joint inner cylinder member 9. The filter member 50 is made of stainless steel or aluminum alloy, and has a large number of fine holes through which a low-temperature fluid can pass.

  The filter member 50 is formed in a convex cup shape on the downstream side in the flow direction of the low-temperature fluid (the direction of the arrow F in the figure), and the outer peripheral end of the filter member 50 on the upstream side in the flow direction of the low-temperature fluid is a joint. For example, it is fixed to the inner peripheral surface of the inner cylinder member 9 by welding.

The inside of the vacuum heat insulating double pipe 1 may be purged with N ₂ gas, and solid nitrogen and other foreign matters generated from the N ₂ gas remaining after the purge can be captured by the filter member 50. The filter member 50 must be periodically replaced or cleaned, but the filter member 50 can be easily replaced or cleaned by separating the joint structure 10C.

An example in which the embodiment is partially changed will be described.
1) In the joint structure 10, when the joint structure 10 is connected, when the right half of the joint inner cylinder member 9 is inserted into the inner pipe enlarged diameter portion 7 b, the following structure is configured. Also good.
The right half of the outer cylindrical body 9b is formed in a tapered shape (partial conical shape) that decreases in diameter toward the right, and the inner pipe enlarged diameter portion 7b is also formed in the same tapered shape (partial conical shape).

2) In the joint structure 10, instead of the joint flanges 13a and 13b, a pair of fastening parts including a male screw part and a female screw part may be fastened.
3) The structure of the right half of the joint outer cylinder member 27B of the joint structure 10B may be the same as the structure of the left half, and the structure of the outer pipe reduced diameter part 32bB may be the same as the structure of the outer pipe reduced diameter part 32a. .
4) Although the joint structures 10, 10A, 10B, and 10C have been described by taking a horizontal posture as an example for convenience of explanation, they may be used in a standing posture in practice.
5) In addition, it goes without saying that those skilled in the art can implement the present invention in a form in which various modifications are added to the joint structure of the above embodiment.

  The present invention provides a joint structure of a vacuum heat insulating double pipe for low-temperature fluid that flows liquefied hydrogen or the like.

1, 1A, 1B Vacuum insulated double pipes 2a, 2b Inner pipes 3a, 3b Outer pipes 4a, 4b Vacuum layers 6a, 6b Annular wall parts 7a, 7b Inner pipe diameter-enlarged parts 9 Inner tube members 10, 10A, 10B for joints Joint structure 13a, 13b Joint flange (fastening part)
26a, 26b Joint flange portion 27, 27B Joint outer cylinder member 27U, 27L Split outer cylinder member 29 Connection flange 30a, 30b, 30bB Reduced diameter outer pipe 32a, 32b, 32bB Outer pipe reduced diameter part 31a, 31b Joint flange 41a, 41b Vacuum layer 50 Filter member

Claims (4)

In a joint structure of a vacuum insulated double pipe for low-temperature fluid having an inner pipe and an outer pipe fitted with a vacuum layer between the inner pipe and the outer pipe,
An inner pipe diameter-enlarged portion is formed by expanding the inner pipe in each of the predetermined length portions of the connection end side of the pair of vacuum heat insulating double pipes,
Provided on the inner peripheral side of the pair of inner pipe enlarged diameter portions is an inner tube member for a joint of a vacuum heat insulating double pipe structure having the same inner diameter as the inner pipe,
A joint structure of a vacuum insulated double pipe for low-temperature fluid, wherein a pair of fastening parts provided at ends of a pair of vacuum insulated double pipes are fastened by a plurality of fastening members.   The joint structure of a vacuum insulated double pipe for low-temperature fluid according to claim 1, wherein a filter member that traps foreign matters in the low-temperature fluid is mounted inside the inner cylinder member for joint. The filter member is formed in a convex cup shape on the downstream side in the flow direction of the cryogenic fluid,
The vacuum heat insulating double pipe for cryogenic fluid according to claim 2, wherein the outer peripheral end of the filter member on the upstream side in the flow direction of the cryogenic fluid is fixed to the inner peripheral surface of the joint inner cylinder member. Joint structure. In a joint structure of a vacuum insulated double pipe for low-temperature fluid having an inner pipe and an outer pipe fitted with a vacuum layer between the inner pipe and the outer pipe,
A pair of vacuum-insulated double pipes each having a predetermined length portion on the connecting end side is formed with an outer pipe reduced diameter portion formed by reducing the diameter of the outer pipe, and a pair of outer pipes joined to the outer pipe reduced diameter portion. The joint flange is provided,
On the outer peripheral side of the pair of outer pipe diameter-reduced portions, a joint outer cylinder member having a vacuum heat insulating double pipe structure in which joint flange portions are provided at both ends,
The pair of joint flanges are fastened to the corresponding joint flange portions of the joint outer cylinder member by a plurality of fastening members, respectively.
The joint outer cylinder member is composed of a plurality of divided outer cylinder members,
The joint structure of a vacuum insulated double pipe for low-temperature fluid, wherein the plurality of divided outer cylinder members are connected by fastening each set of connection flanges with a plurality of fastening members.