Insulated piping

Abstract

SOLUTION: A heat insulation pipeline 10 includes an internal cylinder 20 and an external cylinder 30. The internal cylinder 20 includes a pair of inner pipe members 22, 24 arranged at intervals with each other in an axial direction, a first bellows 25 arranged between the pair of inner pipe members 22, 24, and a regulation mechanism 40 for regulating expansion and contraction of the internal cylinder 20 in an axial direction within a predetermined range. The regulation mechanism 40 is slidable relative to at least one of a pair of swelling parts 28. The external cylinder 30 includes a pair of outer pipe members 32, 33 having a second bellows 34, and a second pipe member 38 accommodating the first bellows 25 and the regulation mechanism 40.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a heat-insulating pipe. [Background Art]

[0002] Conventionally, in a heat-insulating pipe having a double-pipe structure, a configuration provided with a bellows for absorbing axial deformation (thermal expansion or thermal contraction) accompanying temperature changes is known. When laying pipes over a long distance, a plurality of heat-insulating pipes as unit pipes are sequentially connected. In order to suppress non-uniform expansion and contraction amounts of each bellows, for example, Patent Document 1 proposes a configuration in which a projection and a restraining fitting are provided on the pipe. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Utility Model Publication No. 58-9164 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] In the configuration shown in Fig. 1 of Patent Document 1, apart from the outer pipe constituting the outside of the double pipe (referred to as "protective outer pipe 3" in Patent Document 1), a cylindrical member (referred to as "outer pipe 12" in Patent Document 1) to which the restraining fitting is attached is required. For this reason, the outer diameter of the entire pipe increases, and the number of pipe parts increases. In addition, the configuration shown in Fig. 4 of Patent Document 1 can only cope with deformation in one direction (the direction in which the bellows provided at the axial center of the inner pipe expands).

[0005] An object of the present invention is to solve the above-mentioned problems. [Means for Solving the Problem]

[0006] One aspect of the present invention is an insulated pipe comprising an inner cylinder and an outer cylinder enclosing the inner cylinder, wherein both ends of the outer cylinder and the inner cylinder are joined to seal the inside of the outer cylinder, the inner cylinder having a first cylindrical portion and a bulge portion projecting radially outward from the outer circumferential surface of the first cylindrical portion, a pair of inner pipe members spaced apart from each other in the axial direction of the inner cylinder, a first bellows positioned between the pair of inner pipe members to absorb thermal expansion or contraction of the pipe due to the temperature of the fluid flowing inside the pipe, and the front of one of the inner pipe members The insulated pipe comprises: a bulging portion and a regulating mechanism connected to the bulging portion of the other inner pipe member, which restricts the expansion and contraction of the inner cylinder in the axial direction to a predetermined range, wherein the regulating mechanism is slidable with at least one of the pair of bulging portions; the outer cylinder has a second bellows that can expand and contract along the axial direction of the inner cylinder; a pair of outer pipe members joined to the pair of inner pipe members, respectively; and a second cylindrical portion disposed between the pair of outer pipe members, which houses the first bellows and the regulating mechanism. [Effects of the Invention]

[0007] According to the present invention, a regulating mechanism that restricts the amount of deformation of the first bellows due to thermal expansion or contraction of the pipe to which the insulated piping is applied to within a predetermined range is arranged inside the outer cylinder (the space formed between the outer cylinder and the inner cylinder), so that the increase in the outer diameter of the insulated piping that would occur with the provision of the regulating mechanism can be suppressed. Since the regulating mechanism restricts the amount of deformation (expansion and contraction) of the first bellows to within a predetermined range, it can exert a deformation regulating function for both thermal expansion and thermal contraction. Because the inner cylinder and the regulating mechanism are integrated, when assembling the insulated piping, the inner cylinder integrated with the regulating mechanism can be placed inside the outer cylinder, and the inner pipe member of the inner cylinder can be positioned at the opening of the outer pipe member of the outer cylinder. For this reason, the insulated piping can be easily assembled. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a cross-sectional view of an insulated pipe according to one embodiment of the present invention. [Figure 2] Figure 2 is a perspective view of the inner pipe member. [Figure 3] Figure 3 is a schematic diagram showing an example of the application of insulated piping. [Modes for carrying out the invention]

[0009] The insulated piping 10 according to this embodiment, shown in Figure 1, is used in a transfer line for transporting low-temperature or high-temperature fluids. The fluid to be transported is either a liquid or a gas. In this case, the liquid may be, for example, a liquid fuel (such as cryogenic liquid nitrogen). The gas may be, for example, exhaust gas or a gaseous refrigerant.

[0010] The insulated pipe 10 comprises an inner cylinder 20 and an outer cylinder 30 enclosing the inner cylinder 20. Both ends of the outer cylinder 30 are joined to the inner cylinder 20, sealing the inside of the outer cylinder 30. The space between the inner cylinder 20 and the outer cylinder 30 forms an insulated chamber 12. The insulated chamber 12 is depressurized to a predetermined atmospheric pressure and is in a vacuum state. Instead of the insulated chamber 12 being in a vacuum state, it may be filled with an inert gas. Examples of inert gases include nitrogen gas and argon gas. Since an insulating effect can be obtained even if the insulated chamber 12 is not depressurized, it may be filled with air at atmospheric pressure.

[0011] The hollow portion of the inner cylinder 20 serves as a fluid passage. The inner cylinder 20 comprises a pair of inner tube members 22 and 24, and a first bellows 25 positioned between the pair of inner tube members 22 and 24. The pair of inner tube members 22 and 24 are spaced apart from each other in the axial direction of the inner cylinder 20. Each of the pair of inner tube members 22 and 24 has a first cylindrical portion 26 and a bulge portion 28 that protrudes radially outward from the outer circumferential surface of the first cylindrical portion 26.

[0012] The first cylindrical section 26 is a straight pipe with an inner diameter and outer diameter that are approximately constant in the axial direction. The bulging section 28 protrudes radially outward from one end of the first cylindrical section 26 in the axial direction. The bulging section 28 has a through hole 29 that penetrates through it in the axial direction.

[0013] As shown in Figure 2, the bulging portion 28 has a circular ring-shaped flange portion 281 that protrudes radially outward from the outer circumferential surface of one axial end of the first cylindrical portion 26 and extends in the circumferential direction, and a projection portion 282 that protrudes radially outward from the outer circumferential surface of the flange portion 281. In this embodiment, a plurality of projection portions 282 are arranged at intervals in the circumferential direction. Through holes 29 are provided in each projection portion 282. Therefore, each inner tube member 22, 24 has a plurality of through holes 29.

[0014] In Figure 2, three protrusions 282 are arranged at 120° intervals, but the number and spacing of the protrusions 282 are not limited to this. Each inner tube member 22, 24 may have only one protrusion 282, or it may have four or more.

[0015] As shown in Figure 1, one axial end of the first bellows 25 is joined to one end of one inner tube member 22 (the end on the side with the bulge 28). The other axial end of the first bellows 25 is joined to one end of the other inner tube member 24 (the end on the side with the bulge 28). The first bellows 25 absorbs the thermal expansion or contraction of the inner cylinder 20 due to the temperature of the fluid flowing inside the inner cylinder 20.

[0016] The first bellows 25 has a plurality of peaks 251 that constitute the outer circumference of the first bellows 25 and a plurality of valleys 252 that constitute the inner circumference of the first bellows 25. The plurality of peaks 251 and the plurality of valleys 252 are arranged alternately in the axial direction and connected to each other, so that the first bellows 25 is expandable and contractible in the axial direction. The axial length of the first bellows 25 is longer than the axial length of the inner tube members 22 and 24. However, the axial length of the first bellows 25 may be less than or equal to the axial length of the inner tube members 22 and 24.

[0017] The cross-section of the first bellows 25 along its axial direction is a first corrugated cross-section having arc-shaped peaks 251 and arc-shaped valleys 252. Therefore, the first corrugated cross-section has a shape formed by connecting multiple S-shapes in the axial direction. The peaks 251 of the first bellows 25 have a C-shaped or U-shaped cross-sectional shape. The valleys 252 of the first bellows 25 have a C-shaped or U-shaped cross-sectional shape. Because the first bellows 25 has the above-described first corrugated cross-section, it has flexibility not only in the axial direction of the inner cylinder 20 but also in the direction perpendicular to the axis Ax of the inner cylinder 20. That is, the first bellows 25 can be deformed in a bending manner. Because the first bellows 25 has the above-described first corrugated cross-section, it has pressure resistance that can withstand the pressure applied to the first bellows 25 due to the reduced pressure in the insulated chamber 12 and the pressure of the fluid flowing inside the inner cylinder 20. In this embodiment, the intermediate section 253 connecting the peak section 251 and the valley section 252 is inclined with respect to a plane perpendicular to the axis Ax of the inner cylinder 20. Alternatively, the intermediate section 253 may be parallel to the plane perpendicular to the axis Ax of the inner cylinder 20.

[0018] The inner cylinder 20 further comprises a regulating mechanism 40 connected to a pair of inner tube members 22 and 24. The regulating mechanism 40 is connected to the bulge 28 of one inner tube member 22 and the bulge 28 of the other inner tube member 22. The regulating mechanism 40 restricts the expansion and contraction of the inner cylinder 20 in the axial direction to a predetermined range. The regulating mechanism 40 is slidable with at least one of the pair of bulge portions 28. Multiple regulating mechanisms 40 are arranged around the inner cylinder 20 at intervals from each other in the circumferential direction.

[0019] The regulating mechanism 40 has a connecting rod 42 that extends along the axial direction of the inner cylinder 20. One end of the connecting rod 42 is inserted through a through hole 29 in one inner tube member 22. The other end of the connecting rod 42 is inserted through a through hole 29 in the other inner tube member 24.

[0020] The restricting mechanism 40 further includes a pair of restricting portions 44 (a first restricting portion 44A and a second restricting portion 44B). The pair of restricting portions 44 are spaced apart from each other in the axial direction, fixed to the outer peripheral portion of the connecting rod 42, and protrude from the outer peripheral portion of the connecting rod 42. A portion of the connecting rod 42 located between the pair of restricting portions 44 is inserted through the through hole 29. The pair of restricting portions 44 are disposed on one end side of the connecting rod 42. In the present embodiment, each restricting portion 44 is constituted by two nuts 45 screwed onto the connecting rod 42. The two nuts 45 constituting each restricting portion 44 are adjacent to each other in the axial direction and abut against each other. It should be noted that the form of the restricting portion 44 is not limited to the nut 45, and may be, for example, a convex portion integrally formed on the outer peripheral portion of the connecting rod 42.

[0021] The distance between the pair of restricting portions 44 is larger than the axial thickness of the bulging portion 28 (protruding portion 282). For this reason, one end side of the connecting rod 42 is inserted through the through hole 29 of one inner pipe member 22 so as to be slidable in the axial direction. The upper limit of the axial deformation amount of the inner cylinder 20 during thermal expansion and thermal contraction is defined by the distance between the pair of restricting portions 44. Specifically, when the first bellows 25 receives a force in the axially extending direction, the bulging portion 28 of one inner pipe member 22 abuts against the first restricting portion 44A as the first bellows 25 extends, thereby preventing the first bellows 25 from being further extended. When the first bellows 25 receives a force in the axially compressing direction, the bulging portion 28 of one inner pipe member 22 abuts against the second restricting portion 44B as the first bellows 25 contracts, thereby preventing the first bellows 25 from contracting further.

[0022] The regulating mechanism 40 further comprises a fixing member 46 that fixes the other end side of the connecting rod 42 to the bulging portion 28 (specifically, the protruding portion 282) of the other inner pipe member 24. The fixing member 46 comprises a first fixing nut 461 that abuts against one end face of the protruding portion 282, and a second fixing nut 462 that abuts against the other end face of the protruding portion 282. The first fixing nut 461 and the second fixing nut 462 are screwed onto the connecting rod 42. The fixing member 46 prevents relative axial movement between the other end side of the connecting rod 42 and the bulging portion 28 of the other inner pipe member 24. For this reason, the other end side of the connecting rod 42 is inserted through the through hole 29 of the other inner pipe member 24 in a non-slidable manner. The fixing means for fixing the other end side of the connecting rod 42 to the bulging portion 28 (protruding portion 282) of the other inner pipe member 24 is not limited to the above embodiment, and may be welding, for example. Note that, similarly to the one end side of the connecting rod 42, the other end side of the connecting rod 42 may also be slidably inserted through the through hole 29 of the other inner pipe member 24.

[0023] The outer cylinder 30 is arranged coaxially with the inner cylinder 20. A double pipe is constituted by the inner cylinder 20 and the outer cylinder 30. The outer cylinder 30 comprises a pair of outer pipe members 32, 33, and a second cylindrical portion 38 arranged between the pair of outer pipe members 32, 33. The pair of outer pipe members 32, 33 are respectively joined to the pair of inner pipe members 22, 24. Each of the pair of outer pipe members 32, 33 comprises a second bellows 34 that can expand and contract along the axial direction of the inner cylinder 20. Each outer pipe member 32, 33 further comprises a large-diameter ring member 36 joined to one end of the second bellows 34, and a small-diameter ring member 37 joined to the other end of the second bellows 34.

[0024] The second bellows 34 comprises a plurality of crest portions 341 constituting the outer peripheral portion of the second bellows 34, and a plurality of trough portions 342 constituting the inner peripheral portion of the second bellows 34. The plurality of crest portions 341 and the plurality of trough portions 342 are alternately arranged in the axial direction and connected to each other, whereby the second bellows 34 has elasticity in the axial direction. The inner diameter of the second bellows 34 is larger than the outer diameter of the first cylindrical portion 26 of the inner pipe members 22, 24.

[0025] The wave shape of the second bellows 34 differs from that of the first bellows 25. The cross-section of the second bellows 34 along the axial direction is a second corrugated cross-section having V-shaped peaks 341 and V-shaped valleys 342. Therefore, the second corrugated cross-section has a shape in which multiple V-shapes facing opposite directions are connected in the axial direction. The outer diameter of the second bellows 34 is less than or equal to the outer diameter of the second cylindrical portion 38. The second bellows 34 is constructed by connecting multiple annular plate materials 340 in series. Specifically, the outer circumferences of adjacent plate materials 340 are connected to each other, and the inner circumferences of adjacent plate materials 340 are connected to each other. The spring constant of the second bellows 34 is smaller than that of the first bellows 25.

[0026] One large-diameter ring member 36 of the outer tube member 32 is joined to one end of the second cylindrical portion 38. The other large-diameter ring member 36 of the outer tube member 33 is joined to the other end of the second cylindrical portion 38. The outer diameter of each large-diameter ring member 36 is approximately the same as the outer diameter of the second cylindrical portion 38. The large-diameter ring member 36 has an annular first outer peripheral wall 361 joined to the second cylindrical portion 38, and an annular first side wall 362 that protrudes radially inward from the end of the first outer peripheral wall 361 opposite to the second cylindrical portion 38. The inner circumference of the first side wall 362 is joined to one end of the second bellows 34.

[0027] In each of the outer tube members 32 and 33, a small-diameter ring member 37 is joined to the other end of the second bellows 34. The outer diameter of the small-diameter ring member 37 is smaller than the outer diameter of the second cylindrical portion 38 and the outer diameter of the second bellows 34. The small-diameter ring member 37 has an annular second outer peripheral wall 371 joined to the other end of the second bellows 34, and an annular second side wall 372 that protrudes radially inward from the end of the second outer peripheral wall 371 opposite to the second bellows 34. The inner circumference of the second side wall 372 is joined to the outer circumference of the inner tube members 22 and 24 at the end of the inner tube members 22 and 24 opposite to the first bellows 25. The first cylindrical portions 26 of the inner tube members 22 and 24 protrude axially from the outer tube members 32 and 33 (specifically, the second side wall 372 of the small-diameter ring member 37).

[0028] The second cylindrical section 38 houses the first bellows 25 and the regulating mechanism 40. The second cylindrical section 38 is a straight tube with an inner diameter and outer diameter that are approximately constant in the axial direction. The inner diameter of the second cylindrical section 38 is set to a size such that the inner circumferential surface of the second cylindrical section 38 does not come into contact with the bulging portions 28 (projections 282) of the inner tube members 22 and 24 and the regulating mechanism 40. That is, the distance from the axis Ax of the inner cylinder 20 to the inner circumferential surface of the second cylindrical section 38 (the radius of the inner diameter of the second cylindrical section 38) is greater than the distance from the axis Ax of the inner cylinder 20 to the tip of the projection 282 of the inner tube members 22 and 24, and the distance from the axis Ax of the inner cylinder 20 to the point of the regulating mechanism 40 furthest from the axis Ax. The axial length of the second cylindrical section 38 is longer than the axial length of the outer tube members 32 and 33.

[0029] Figure 3 shows one example of the application of the insulated piping 10. A transfer line 64 is connected to a liquefied refrigerator 60 and a device to be supplied 62. Cryogenic refrigerant is supplied from the liquefied refrigerator 60 to the device to be supplied 62 via the transfer line 64. To absorb the thermal contraction of the transfer line 64 through which the cryogenic refrigerant flows, the transfer line 64 is equipped with a thermal contraction structure. Specifically, the transfer line 64 has a plurality of piping members 66 (pipe bodies) and a plurality of insulated pipes 10 arranged as joint devices between the plurality of piping members 66. As shown in Figure 1, the insulated pipe 10 is equipped with a regulating mechanism 40 that restricts the amount of deformation of the insulated pipe 10 due to thermal expansion or contraction of the first bellows 25 to within a predetermined range, so that the amount of expansion and contraction of the first bellows 25 does not become uneven in the plurality of insulated pipes 10.

[0030] The insulated pipe 10 may be used as a joint device for the exhaust pipe of an automobile or the like. However, the insulated pipe 10 is not limited to being used as a joint device. Multiple insulated pipes 10 may be connected to each other to form a long pipe.

[0031] This embodiment provides the following effects.

[0032] As shown in Figure 1, the regulating mechanism 40, which restricts the amount of deformation of the inner cylinder 20 (first bellows 25) due to thermal expansion or contraction of the pipe to which the insulated piping 10 is applied, to a predetermined range, is located inside the outer cylinder 30 (in the space formed between the outer cylinder 30 and the inner cylinder 20). Therefore, the increase in the outer diameter of the insulated piping 10 due to the provision of the regulating mechanism can be suppressed. Since the regulating mechanism 40 restricts the amount of deformation (expansion and contraction) of the first bellows 25 to a predetermined range, it can exert a deformation regulation function for both thermal expansion and thermal contraction. Because the inner cylinder 20 and the regulating mechanism 40 are integrated, when assembling the insulated piping 10, the inner cylinder 20 integrated with the regulating mechanism 40 can be placed inside the outer cylinder 30, and the inner pipe members 22 and 24 of the inner cylinder 20 can be positioned at the openings of the outer pipe members 32 and 33 of the outer cylinder 30. For this reason, the insulated piping 10 can be easily assembled.

[0033] The regulating mechanism 40 has a connecting rod 42 that extends along the axial direction of the inner cylinder 20. The bulging portion 28 has a through hole 29 that penetrates axially. A portion of the connecting rod 42 is slidably inserted through the through hole 29. With this configuration, the connecting rod 42 is guided axially by the through hole 29, so that the deformation regulating function can be properly performed during thermal expansion and contraction of the piping.

[0034] The regulating mechanism 40 has a pair of regulating portions 44 fixed to the outer circumference of the connecting rod 42 at intervals from each other in the axial direction and protruding from the outer circumference. The portion of the connecting rod 42 between the pair of regulating portions 44 is inserted through the through hole 29. With this configuration, the range of motion of the projection on the connecting rod 42 is defined between the pair of regulating portions 44, so that the expansion and contraction of the inner cylinder 20 can be effectively restricted within a predetermined range.

[0035] Multiple regulating mechanisms 40 are arranged around the inner cylinder 20 at intervals from each other in the circumferential direction. This configuration distributes the regulating load on the regulating mechanisms 40 during thermal expansion and contraction of the insulated piping 10 in the circumferential direction, thereby enabling the deformation regulating function to be performed even more effectively.

[0036] When the space between the inner cylinder 20 and the outer cylinder 30 is reduced to a predetermined pressure, a high level of thermal insulation can be achieved.

[0037] When the space between the inner cylinder 20 and the outer cylinder 30 is filled with an inert gas, a high level of heat insulation can be obtained.

[0038] The waveforms of the first bellows 25 and the second bellows 34 have different shapes. This configuration allows for the adoption of optimal bellows shapes in both the inner cylinder 20 and the outer cylinder 30, thereby enabling the entire insulated piping 10 to exhibit even better thermal expansion and contraction absorption functions.

[0039] The axial cross-section of the first bellows 25 is a first corrugated cross-section having arc-shaped peaks 251 and arc-shaped valleys 252. The axial cross-section of the second bellows 34 is a second corrugated cross-section having V-shaped peaks 341 and V-shaped valleys 342. The corrugated cross-section in which the peaks 251 and valleys 252 are arc-shaped is suitable for the cross-sectional shape of the first bellows 25 of the inner pipe that receives pressure from the fluid flowing inside, because it is more likely to deform by bending as a whole rather than collapsing under external forces received from the axial direction. The corrugated cross-section in which the peaks 341 and valleys 342 are V-shaped is suitable for the cross-sectional shape of the second bellows 34 that receives deformation of the entire insulated pipe 10, because it is more likely to collapse under external forces received from the axial direction.

[0040] In addition to the disclosures mentioned above, the following further notes are made:

[0041] (Note 1) An insulated pipe (10) comprising an inner cylinder (20) and an outer cylinder (30) enclosing the inner cylinder, wherein both ends of the outer cylinder and the inner cylinder are joined to seal the inside of the outer cylinder, the inner cylinder having a first cylindrical portion (26) and a bulge portion (28) projecting radially outward from the outer circumferential surface of the first cylindrical portion, a pair of inner pipe members (22, 24) spaced apart from each other in the axial direction of the inner cylinder, a first bellows (25) positioned between the pair of inner pipe members to absorb thermal expansion or contraction of the pipe due to the temperature of the fluid flowing inside the pipe, and one of the inner The outer cylinder comprises a regulating mechanism (40) connected to the bulging portion of the pipe member and the bulging portion of the other inner pipe member, which restricts the expansion and contraction of the inner cylinder in the axial direction to a predetermined range, wherein the regulating mechanism is slidable with at least one of the pair of bulging portions, and the outer cylinder has a second bellows (34) that can expand and contract along the axial direction of the inner cylinder, a pair of outer pipe members (32, 33) joined to the pair of inner pipe members respectively, and a second cylindrical portion (38) disposed between the pair of outer pipe members and housing the first bellows and the regulating mechanism. With this configuration, since the regulating mechanism that restricts the amount of deformation of the first bellows due to thermal expansion or contraction of the pipe to which the insulated piping is applied to to a predetermined range is located inside the outer cylinder (in the space formed between the outer cylinder and the inner cylinder), it is possible to suppress the increase in the outer diameter of the insulated piping that would occur with the provision of the regulating mechanism. Since the regulating mechanism restricts the amount of deformation (expansion and contraction) of the first bellows to a predetermined range, it can exert a deformation amount regulating function for both thermal expansion and thermal contraction. Because the inner cylinder and the regulating mechanism are integrated, when assembling the insulated piping, the inner cylinder, which is integrated with the regulating mechanism, can be placed inside the outer cylinder, and the inner pipe member of the inner cylinder can be positioned at the opening of the outer pipe member of the outer cylinder. Therefore, the insulated piping can be easily assembled.

[0042] (Note 2) In the insulated piping described in Appendix 1, the regulating mechanism has a connecting rod (42) extending along the axial direction of the inner cylinder, and the bulging portion has a through hole (29) penetrating in the axial direction, and a part of the connecting rod may be slidably inserted through the through hole. With this configuration, the connecting rod is guided in the axial direction by the through hole, so that the deformation regulating function can be appropriately performed when the piping undergoes thermal expansion and contraction. Furthermore, even when an axial load is applied to the piping, the presence of the connecting rod prevents the first bellows from buckling. For example, when a piping layout as shown in Figure 3 is adopted, the load caused by the difference in the amount of expansion or contraction of each component constituting the piping can become an axial load on the piping.

[0043] (Note 3) In the insulated piping described in Appendix 2, the regulating mechanism has a pair of regulating parts (44) fixed to the outer circumference of the connecting rod at intervals from each other in the axial direction and protruding from the outer circumference, and the portion of the connecting rod between the pair of regulating parts may be inserted into the through hole. With this configuration, the range of motion of the projection on the connecting rod is defined between the pair of regulating parts, so that the expansion and contraction of the inner cylinder can be effectively restricted to a predetermined range.

[0044] (Note 4) In the insulated piping described in any one of the appendices 1 to 3, the regulating mechanisms may be arranged in multiples at intervals from one another in the circumferential direction of the inner cylinder. This configuration distributes the regulating load on the regulating mechanisms in the circumferential direction when the insulated piping expands and contracts due to heat, thereby enabling the deformation regulating function to be performed more effectively.

[0045] (Note 5) In the insulated piping described in any one of the appendices 1 to 4, the space between the inner cylinder and the outer cylinder may be reduced to a predetermined atmospheric pressure. This configuration provides a high level of insulation.

[0046] (Note 6) In the insulated piping described in any one of the appendices 1 to 4, the space between the inner cylinder and the outer cylinder may be filled with an inert gas. This configuration provides a high level of insulation.

[0047] (Note 7) In the insulated piping described in any one of the appendices 1 to 6, the corrugations of the first bellows and the second bellows may have different shapes. This configuration allows for the adoption of optimal bellows shapes for both the inner and outer cylinders, thereby enabling the entire insulated piping to exhibit even better thermal expansion and contraction absorption functions.

[0048] (Note 8) In the insulated piping described in Appendix 7, the axial cross-section of the first bellows is a first corrugated cross-section having a C-shaped or U-shaped curved peak (251) and a C-shaped or U-shaped curved valley (252), and the axial cross-section of the second bellows may be a second corrugated cross-section having a V-shaped bendable peak (341) and a V-shaped bendable valley (342). A corrugated cross-section in which the peaks and valleys are curved in an arc shape is more likely to deform by bending as a whole rather than collapsing under external forces from the axial direction, and is therefore suitable as the cross-sectional shape of the first bellows of an inner pipe that receives pressure from the fluid flowing inside. A corrugated cross-section in which the peaks and valleys are bent in a V shape is more likely to collapse under external forces from the axial direction, and is therefore suitable as the cross-sectional shape of the second bellows that receives deformation of the entire insulated piping.

[0049] (Note 9) In the insulated piping described in Appendix 8, the second bellows is constructed by connecting a plurality of annular plate materials (340) in series, with the outer periphery of adjacent plate materials being connected to each other, and the inner periphery of adjacent plate materials being connected to each other.

[0050] Furthermore, the present invention is not limited to the disclosure described above, and can take various configurations without departing from the spirit of the invention. [Explanation of Symbols]

[0051] 10…Insulated piping 20…Inner cylinder 22, 24... Inner pipe members 25...1st bellows 26...First cylindrical section 30…Outer cylinder 32, 33...Outer pipe member 34...2nd bellows 38...Second cylindrical section 40… Regulatory body

Claims

1. An insulated pipe comprising an inner cylinder and an outer cylinder enclosing the inner cylinder, wherein both ends of the outer cylinder and the inner cylinder are joined together, and the inside of the outer cylinder is sealed, The inner cylinder is A pair of inner tube members are arranged at intervals from each other in the axial direction of the inner cylinder, each having a first cylindrical portion and a bulging portion that protrudes radially outward from the outer circumferential surface of the first cylindrical portion. A first bellows is positioned between the pair of inner pipe members and absorbs the thermal expansion or contraction of the pipe due to the temperature of the fluid flowing inside the pipe, The device comprises a regulating mechanism connected to the bulging portion of one inner tube member and the bulging portion of the other inner tube member, which restricts the expansion and contraction of the inner cylinder in the axial direction to a predetermined range, The regulating mechanism is slidable with at least one of the pair of bulging portions, The outer cylinder is, The inner cylinder has a second bellows that is expandable and contractible along the axial direction, and a pair of outer tube members are joined to the pair of inner tube members, An insulated pipe comprising: a second cylindrical portion disposed between the pair of outer pipe members and housing the first bellows and the regulating mechanism.

2. In the insulated piping according to claim 1, The regulating mechanism has a connecting rod that extends along the axial direction of the inner cylinder, The bulging portion has a through hole that penetrates in the axial direction, An insulated pipe in which a portion of the connecting rod is slidably inserted through the aforementioned through hole.

3. In the insulated piping according to claim 2, The regulating mechanism has a pair of regulating parts fixed to the outer circumference of the connecting rod at intervals from each other in the axial direction and protruding from the outer circumference. An insulated pipe in which the portion of the connecting rod between the pair of restricting portions is inserted through the through hole.

4. In the insulated piping according to claim 1, The regulating mechanism comprises multiple insulated pipes arranged at intervals from one another in the circumferential direction of the inner cylinder.

5. In the insulated piping according to claim 1, An insulated pipe in which the space between the inner cylinder and the outer cylinder is depressurized to a predetermined atmospheric pressure.

6. In the insulated piping according to claim 1, An insulated pipe in which the space between the inner cylinder and the outer cylinder is filled with an inert gas.

7. In the insulated piping according to any one of claims 1 to 6, An insulated pipe in which the waveform of the first bellows and the waveform of the second bellows have different shapes from each other.

8. In the insulated piping according to claim 7, The cross-section of the first bellows along the axial direction is a first corrugated cross-section having a peak that curves in a C-shape or U-shape and a valley that curves in a C-shape or U-shape, Insulated piping, the cross-section of the second bellows along its axial direction is a second corrugated cross-section having V-shaped peaks and V-shaped valleys.

9. In the insulated piping according to claim 8, The second bellows is an insulated pipe in which a plurality of annular plate-shaped plates are connected in series, with the outer periphery of adjacent plates connected to each other and the inner periphery of adjacent plates connected to each other.

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