piping for the transfer of cryogenic fluid

Abstract

The invention relates to a pipeline (1) comprising an outer casing (2) and an inner conduit (3) for the transfer of cryogenic fluid, the inner conduit (3) extending inside the outer casing (2), the outer casing (2) and the inner conduit (3) defining between them an internal space (14), the pipeline (1) comprising a first section (4) having a first thermal barrier (8) connected at one of its ends (9) to the outer casing (2) and at the other of its ends (7) to the inner conduit (3), the first thermal barrier (8) extending inside the internal space (14), the first thermal barrier (8) having a first thermal compensator (10). Abstract figure: Figure 1.

Description

Title of the invention: pipe for the transfer of cryogenic fluid

[0001] The present invention relates to a pipeline for the transfer of cryogenic fluid and a method of assembling such a pipeline.

[0002] The invention relates more particularly to a double-walled pipe for transferring cryogenic fluid, comprising an outer casing and at least one internal pipe for transferring the cryogenic fluid, the internal pipe extending inside the outer casing, the outer casing and the internal pipe defining between them an internal space, in particular an annular space, intended to be placed under vacuum, the pipe comprising a first section comprising a first thermal barrier connected by one of its ends to the outer casing and by the other of its ends to the internal pipe, the first thermal barrier extending inside the internal space.

[0003] A double-walled vacuum pipeline is manufactured in a workshop, in the form of a plurality of first prefabricated sections with the presence of a sealed vacuum, a first section being connected, on site, to the rest of the pipeline via a connecting section.

[0004] A pipeline of this type is subject to phenomena of expansion and contraction of some of its components mainly due to the cold generated by the cryogenic fluid circulating in the internal pipe.

[0005] A known solution consists of using a thermal compensator formed on the connection section, the thermal compensator being interposed between two thermal barriers.

[0006] This type of solution has the disadvantage of multiplying the number of thermal compensators at the level of the internal pipe of the pipeline, which presents a risk of leaks.

[0007] An aim of the present invention is to overcome all or part of the drawbacks of the prior art noted above.

[0008] The present invention, in accordance with the generic definition given in the preamble above, is characterized in that the first thermal barrier comprises a first thermal compensator, in particular configured to compensate for the thermal expansion / contraction of the internal pipe relative to the external envelope.

[0009] This makes it possible to compensate for deformations in the piping without requiring the presence of a thermal compensator at the level of the internal pipe of each section.

[0010] Furthermore, this makes it possible to prevent the thermal compensator from coming into contact with the cryogenic fluid. With such a thermal compensator, it is thus possible to ensure sealing for the sealed vacuum of the first section, while accompanying the movements linked to thermal expansion or thermal contraction.

[0011] Finally, such a solution makes it possible to limit pressure losses at the level of the internal conduit of the pipeline.

[0012] According to one embodiment, the pipeline is of the rigid or semi-rigid type.

[0013] According to one embodiment, the first thermal barrier extends between its two ends.

[0014] According to one embodiment, the first thermal barrier extends inside the internal space, to separate the internal space in a sealed manner, between a first portion of the internal space and a second portion of the internal space, each arranged on either side of the first thermal barrier.

[0015] According to one embodiment, the first thermal compensator comprises a first elastic portion, for example a first elastic bellows.

[0016] According to one embodiment, the first elastic portion extends in the direction in which at least a portion of the first section extends.

[0017] According to one embodiment, the first elastic portion is configured to extend or compress in the direction of a first axis, the first axis extending in the direction in which at least the portion of the internal pipe which is opposite the first elastic portion extends.

[0018] According to one embodiment, the first thermal compensator comprises a fixed wall extending in the direction of the first axis, in particular over a length at least equal to that of the first elastic portion, the length being measured along the axis.

[0019] According to one embodiment, the internal conduit is configured to allow the cryogenic fluid to circulate inside the internal conduit without being in contact with the first thermal compensator.

[0020] According to one embodiment, the internal pipe comprises a pipe thermal compensator, arranged on the wall of the internal pipe 3.

[0021] According to one embodiment, the thermal pipe compensator is mounted free relative to the outer casing.

[0022] According to one embodiment, the thermal pipe compensator comprises an elastic pipe bellows.

[0023] According to one embodiment, the first section comprises a second thermal barrier extending inside the internal space.

[0024] According to one embodiment, the second thermal barrier is configured to separate the internal space in a sealed manner.

[0025] According to one embodiment, the second thermal barrier is configured to separate the internal space between the first portion of the internal space and a fourth portion of the internal space, each arranged on either side of the second thermal barrier.

[0026] Alternatively, the second thermal barrier is configured to isolate the first portion of the internal space from the exterior of the pipeline.

[0027] According to one embodiment, the first thermal barrier and the second thermal barrier are configured to maintain the first portion of the internal space under vacuum.

[0028] According to one embodiment, the second thermal barrier comprises a second thermal compensator configured to compensate for the thermal expansion / contraction of the internal pipe relative to the external casing.

[0029] According to one embodiment, the second thermal compensator comprises a second elastic portion, for example an elastic bellows.

[0030] According to one embodiment, the pipeline comprises a connection section connected in a sealed manner to the first section by one of the ends of the connection section.

[0031] According to one embodiment, the connection section comprises an orifice intended to allow a reduction in the pressure of the internal space.

[0032] According to one embodiment, the orifice comprises a hole passing through the outer casing.

[0033] According to one embodiment, the connection section is connected to the first section, on the side of the first thermal barrier.

[0034] According to one embodiment, the connection section comprises a pumping valve, in particular arranged on the outer casing.

[0035] According to one embodiment, the pumping valve is arranged to allow connection with a vacuum pump to allow reduction of the pressure in the internal space.

[0036] According to one embodiment, the connection section is connected to the first section by welding.

[0037] According to one embodiment, the connection section is configured so that its length varies only under the effect of its own thermal expansion / contraction.

[0038] According to one embodiment, the connection section is without thermal compensator to compensate for the thermal expansion / contraction of the internal pipe relative to the external casing.

[0039] According to one embodiment, the internal conduit of the connection section forms a rigid tubular portion extending over at least half the length of the connection section, in particular over the entire length of the connection section.

[0040] According to one embodiment, the pipeline comprises a third section connected in a sealed manner to the connection section by the other of the ends of the connection section, the third section comprising a third thermal barrier connected by one of its ends to the outer casing and by the other of its ends to the internal pipe, the third thermal barrier extending inside the internal space.

[0041] According to one embodiment, the third thermal barrier extends inside the internal space, between the two ends of the third thermal barrier.

[0042] According to one embodiment, the third thermal barrier extends inside the internal space, being configured to separate the internal space in a sealed manner, between the second portion of the internal space and a third portion of the internal space, each arranged on either side of the third thermal barrier.

[0043] According to one embodiment, the third thermal barrier comprises a third thermal compensator.

[0044] According to one embodiment, the third thermal compensator is configured to compensate for the thermal expansion / contraction of the internal pipe relative to the external casing.

[0045] According to one embodiment, the third thermal compensator comprises a third elastic portion, for example a third elastic bellows.

[0046] According to one embodiment, the third section comprises a fourth thermal barrier connected by one of its ends to the outer casing and by the other of its ends to the internal pipe, the fourth thermal barrier extending inside the internal space.

[0047] According to one embodiment, the fourth thermal barrier is configured to separate the internal space in a sealed manner, between the third portion of the internal space and a fifth portion of the internal space, each arranged on either side of the fourth thermal barrier.

[0048] Alternatively, the fourth thermal barrier is configured to isolate the third portion of the internal space from the exterior of the pipeline.

[0049] According to one embodiment, the pipeline comprises a plurality of first sections and / or third sections and / or connection sections.

[0050] The invention further relates to a method for assembling a double-walled pipeline for transferring cryogenic fluid, comprising the following steps: - providing an outer jacket and at least one internal pipe for transferring the cryogenic fluid, the internal pipe extending inside the outer jacket, the outer jacket and the internal pipe defining between them an internal space, in particular an annular space, intended to be placed under vacuum, the pipeline comprising a first section comprising a first thermal barrier connected by one of its ends to the outer casing and by the other of its ends to the internal pipe, the first thermal barrier extending inside the internal space, the first thermal barrier comprises a first thermal compensator, in particular configured to compensate for the thermal expansion / contraction of the internal pipe relative to the outer casing; - have a connection section with an orifice intended to allow the pressure in the internal space to be reduced; - connect in a watertight manner, in particular by welding, one of the ends of the connection section to one of the ends of the first section; - reduce the pressure in the internal space, in particular by connecting the orifice to a vacuum pump.

[0051] According to one embodiment, the method comprises the following steps: - have a third section comprising a third thermal barrier connected by one of its ends to the outer casing and by the other of its ends to the internal pipe, the third thermal barrier extending inside the internal space; - connect in a watertight manner, in particular by welding, the other end of the connection section to one of the ends of the third section, in particular prior to the step of reducing the pressure in the internal space.

[0052] The invention will be better understood upon reading the following description and examining the accompanying figures. These figures are given only for illustrative purposes but in no way limit the invention.

[0053] [Fig-1] [Fig.l] is a schematic representation of an embodiment of a pipeline according to the invention;

[0054] [Fig.2] [Fig.2] is a schematic representation of another embodiment of a pipeline according to the invention;

[0055] [Fig.3] [Fig.3] is a schematic representation of another embodiment of a pipeline according to the invention; and

[0056] [Fig.4] [Fig.4] is a schematic representation of another embodiment of a pipeline according to the invention.

[0057] Identical, similar, or analogous elements retain the same reference from one figure to another.

[0058] As illustrated in [Fig.l], a double-walled pipeline 1 is shown for the transfer of cryogenic fluid.

[0059] The pipe 1 comprises an outer casing 2 and at least one internal pipe 3, the internal pipe 3 being configured to allow the transfer of a cryogenic fluid.

[0060] The internal pipe 3 extending inside the external casing 2, the external casing 2 and the internal pipe 3 defining between them an internal space 14, 15, 16, in particular annular, intended to be placed under vacuum.

[0061] As visible in [Fig.l], the pipeline 1 comprises a first section 4 comprising a first thermal barrier 8.

[0062] The thermal barrier 8 is connected by one of its ends 9 to the outer casing 2 and by the other of its ends 7 to the internal conduit 3.

[0063] The first thermal barrier 8 extends entirely inside the internal space 14, separating the internal space 14, 15, 16 in a sealed manner, between a first portion 14 of the internal space and a second portion 15 of the internal space, each arranged on either side of the first thermal barrier 8.

[0064] The first thermal barrier 8 does not extend inside the internal conduit 3.

[0065] The first thermal barrier 8 comprises a first thermal compensator 10 configured to compensate for thermal expansion and / or to compensate for thermal contraction of the internal pipe 3 relative to the external casing 2.

[0066] The first thermal compensator 10 comprises a first elastic portion 10, for example a first elastic bellows 10.

[0067] The internal pipe 3 is configured to allow the cryogenic fluid to circulate inside the internal pipe 3 without being in contact with the first thermal compensator 10. Thus, the internal pipe 3 forms an insulating partition between the first thermal compensator 10 and the cryogenic fluid.

[0068] The internal pipe 3 of the first section 4 comprises a rigid or semi-rigid portion, extending in particular over the entire length of the first section 4.

[0069] The first section 4 further comprises a second thermal barrier 11 extending inside the internal space 14, 15, 16 while being configured to separate the internal space in a sealed manner.

[0070] Thus, as shown in [Fig. 1], the first thermal barrier 8 and the second thermal barrier 11 are configured to maintain, together, the first portion of the internal space 14 under vacuum after having been placed under vacuum.

[0071] In the example shown in [Fig.l], the second thermal barrier 11 comprises a second thermal compensator 11 configured to compensate for the thermal expansion / contraction of the internal pipe 3 relative to the external casing 2.

[0072] [Fig.2] represents a variant of the first section 4 of [Fig.l] in which: - the internal pipe 3 comprises a pipe thermal compensator 13, arranged on the wall of the internal pipe 3; and - the second thermal barrier 12 comprises a fixed barrier 12.

[0073] The fixed barrier 12 comprises rigid or semi-rigid walls.

[0074] In another variant of the first section 4 of [Fig. 1], the internal pipe 3 may comprise the pipe thermal compensator 13 as shown in [Fig. 2].

[0075] As shown in [Fig.3], the pipeline 1 comprises a first section 4 as described above.

[0076] The pipe 1 further comprises a connection section 5 connected in a sealed manner to the first section 4 by one of the ends of the connection section 5.

[0077] The pipe 1 further comprises a third section 6 connected in a sealed manner to the connection section 5 by the other end of the connection section 5.

[0078] The connecting section 5 is connected to the first section, on the side of the first thermal barrier 8. More precisely, the first thermal barrier 8 extends longitudinally inside the internal space, from at least one of its ends 7, 9 in the direction of the connecting section 5.

[0079] The connecting section 5 is connected to the first section 4 by at least one weld made on the outer casing 2 and on the internal pipe 3.

[0080] As shown in [Fig. 3], the connecting section 5 is configured so that its length varies only under the effect of its own thermal expansion / contraction. More precisely, the connecting section 5 is devoid of thermal compensator at the level of the internal pipe 3 and at the level of the external casing 2.

[0081] The internal pipe 3 of the connection section 5 forms a rigid tubular portion extending over the entire length of the connection section 5.

[0082] The connecting section 5 comprises an orifice intended to allow a reduction in the pressure of the second portion 15 of the internal space 14, 15, 16.

[0083] The third section 6 comprises a third thermal barrier 18 connected by one of its ends 19 to the outer casing 2 and by the other of its ends 17 to the internal pipe 3, the third thermal barrier 18 extending inside the internal space 14, 15, 16.

[0084] In the example of [Fig.3], the third thermal barrier 18 comprises a third thermal compensator 20.

[0085] The third thermal compensator 20 is configured to compensate for the thermal expansion / contraction of the internal pipe 3 relative to the external casing 2.

[0086] The third thermal compensator 20 comprises a third elastic portion 20, for example a third elastic bellows 20.

[0087] In the same way as for the first section 4, the third section 6 comprises a fourth thermal barrier (not shown in [Fig. 3]) connected by one of its ends to the outer casing 2 and by the other of its ends to the internal pipe 3, the fourth thermal barrier extending inside the internal space.

[0088] The fourth thermal barrier is configured to separate the internal space 14, 15, 16 in a sealed manner, between the third portion of the internal space 16 and a fifth portion of the internal space, each arranged on either side of the fourth thermal barrier.

[0089] Pipeline 1 thus comprises an assembly: - a first section 4 forming a first portion 14 of the internal space 14, 15, 16, this first portion 14 being intended to be placed under vacuum during the manufacture of the first section and being intended to be maintained under vacuum thanks to the first thermal barrier 8 and the second thermal barrier 11; - a third section 6 forming a third portion 16 of the internal space 14, 15, 16, this third portion 16 being intended to be placed under vacuum during the manufacture of the third section 6 and intended to be maintained under vacuum thanks to the third thermal barrier 18 and the fourth thermal barrier; and - a connecting section 5 forming a third portion 15 of the internal space 14, 15, 16, this third portion 15 being intended to be placed under vacuum during the assembly of the connecting section 5 with the first section 4 and with the third section 6.

[0090] [Fig.4] represents a pipeline 1 of the same type as that of [Fig.3], in which: - the third section 6 comprises a second thermal pipe compensator 22, arranged on the wall of the internal pipe 3; - the third thermal barrier 19 comprises a second fixed barrier 19, comprising in particular rigid or semi-rigid walls and being devoid of thermal compensator.

[0091] A method of assembling a pipeline as described above comprises the following steps: - connect in a watertight manner, in particular by welding, one of the ends of the connection section 5 to one of the ends of the first section 4; - connect in a watertight manner, in particular by welding, the other end of the connection section 5 to one of the ends of the third section 6; reducing the pressure in the second portion 15 of the internal space 14, 15, 16, by connecting the orifice of the connecting section 5 to a vacuum pump.

Claims

Claims

1. Double-walled pipe (1) for transferring cryogenic fluid, comprising an outer casing (2) and at least one inner pipe (3) for transferring the cryogenic fluid, the inner pipe (3) extending inside the outer casing (2), the outer casing (2) and the inner pipe (3) defining between them an internal space (14, 15, 16), in particular annular, intended to be placed under vacuum, the pipe (1) comprising a first section (4) comprising a first thermal barrier (8) connected by one of its ends (9) to the outer casing (2) and by the other of its ends (7) to the inner pipe (3), the first thermal barrier (8) extending inside the internal space (14, 15, 16), characterized in that the first thermal barrier (8) comprises a first thermal compensator (10),in particular configured to compensate for the thermal expansion / contraction of the internal pipe (3) relative to the outer casing (2), the internal pipe (3) comprising a thermal pipe compensator (13), arranged on the wall of the internal pipe (3).,

2. Pipe (1) according to the preceding claim, the first thermal compensator (10) comprising a first elastic portion (10), for example a first elastic bellows (10).

3. Pipe (1) according to one of the preceding claims, the internal pipe (3) being configured to allow the cryogenic fluid to circulate inside the internal pipe (3) without being in contact with the first thermal compensator (10).

4. Pipe (1) according to one of the preceding claims, the first section (4) comprising a second thermal barrier (11, 12) extending inside the internal space (14).

5. Pipe (1) according to one of the preceding claims, comprising a connection section (5) connected in a sealed manner to the first section (4) by one of the ends of the connection section (5).

6. Pipe (1) according to the preceding claim, comprising a third section (6) connected in a sealed manner to the connection section (5) by the other of the ends of the connection section (5), the third section (6) comprising a third

7.

8. thermal barrier (18, 21) connected by one of its ends (19) to the outer casing (2) and by the other of its ends (17) to the internal conduit (3), the third thermal barrier (18, 21) extending inside the internal space (16). Pipeline (1) according to the preceding claim, the third thermal barrier (18) comprises a third thermal compensator (20). Method for assembling a double-walled pipeline (1) for transferring cryogenic fluid, comprising the steps of: - having a first section (4) of a double-walled pipeline (1) comprising an outer jacket (2) and at least one internal pipe (3) for transferring the cryogenic fluid, the internal pipe (3) extending inside the outer jacket (2), the outer jacket (2) and the internal pipe (3) defining between them an internal space (14, 15, 16), in particular annular, intended to be placed under vacuum, the first section (4) comprising a first thermal barrier (8) connected by one of its ends (9) to the outer jacket (2) and by the other of its ends (7) to the internal pipe (3), the first thermal barrier (8) extending inside the internal space (14, 15, 16), the first thermal barrier (8) comprising a first thermal compensator (10), in particular configured to compensate for the thermal expansion / contraction of the internal pipe (3) relative to the outer jacket (2),the internal pipe (3) comprising a pipe thermal compensator (13), arranged on the wall of the internal pipe (3);, - have a connection section (5) comprising an orifice intended to allow the reduction of the pressure in the internal space (15); - connect in a watertight manner, in particular by welding, one of the ends of the connection section (5) to one of the ends of the first section (4); - reduce the pressure in the internal space (15), in particular by connecting the orifice to a vacuum pump.

9. Method according to the preceding claim, comprising the steps of: - having a third section (6) comprising a third thermal barrier (18, 21) connected by one of its ends (19) to the outer casing (2) and by the other of its ends (17) to the internal pipe (3), the third thermal barrier (18, 21) extending inside the internal space (16); - connecting in a sealed manner, in particular by welding, the other end of the connection section (5) to one of the ends of the third section (6), in particular prior to the step of reducing the pressure in the internal space (15).

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