Fluid transport pipe

Abstract

To provide a fluid transport pipe which is simple in structure and light in weight.SOLUTION: A fluid transport pipe 1 is mainly constituted of a flexible pipe 3, a resin layer 5, a protection layer 11, and the like. The flexible pipe 3 is located at the innermost layer of the fluid transport pipe 1, excellent in buckling resistance against the external pressure of, for example, an interlock pipe or the like, and formed of stainless steel which is favorable in corrosion resistance. The resin layer 5 is formed at an external peripheral part of the flexible pipe 3. The protection layer 11 is formed at the outermost periphery of the fluid transport pipe 1 being an external peripheral part of an inner pipe 7. The protection layer 11 is a cylindrical member in which high-strength fibers are arranged in a resin being a raw material, and the resin and the high-strength fibers are integrated with each other. Here, as the resin, for example, a polyaramid fiber and a polyurethane fiber are employable. Further, as the high-strength fiber, for example, a polyester fiber and an aramid fiber are employable.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fluid transport pipe capable of transporting a fluid such as a gas or a liquefied gas underwater. [Background technology]

[0002] Conventionally, when transporting fluids such as oil and gas between a floating structure and the seabed underwater (e.g., under the sea), a flexible fluid transport pipe is used. In addition to flexibility, the fluid transport pipe is required to have various properties such as internal pressure resistance that can withstand the internal pressure of the internal fluid.

[0003] Fig. 5 is a schematic diagram showing an example of the use of such a fluid transport pipe. The offshore floating system 100 shown in Fig. 5 is mainly composed of a floating facility 101 and a fluid transport pipe 105 connected thereto. The floating facility 101 is moored to the seabed 109 by a mooring line 111, and the fluid transport pipe 105 is connected to the seabed facility (not shown).

[0004] An example of a fluid transport pipe used in this manner is a flexible fluid transport pipe in which a steel concave reinforcing material is used on the outside of a plastic pipe, the opening side is spirally wound in two layers at a short pitch so that the layers interlock with each other to form an internal pressure reinforcement layer, and an axial force reinforcement layer and a corrosion protection layer are formed on the outer periphery of this (Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 7-156285 Summary of the Invention [Problem to be solved by the invention]

[0006] 6 is a diagram showing a general structure of a conventional fluid transport pipe 105. A general fluid transport pipe 105 is mainly composed of a flexible pipe 117, a resin layer 121, an internal pressure reinforcing layer 125, an axial force reinforcing layer 127, a protective layer 129, and the like.

[0007] The flexible tube 117 is a flexible tube such as an interlock tube, and is surrounded by a resin layer 121 for ensuring airtightness and watertightness of the fluid. Note that a seat layer 119a is provided between the flexible tube 117 and the resin layer 121 as necessary.

[0008] An internal pressure reinforcing layer 125 is provided on the outer periphery of the resin layer 121. The internal pressure reinforcing layer 125 is a reinforcing layer against the internal pressure of the fluid flowing inside the flexible tube 117. The internal pressure reinforcing layer 125 is formed by winding, for example, metallic tapes having a C-shaped or Z-shaped cross section at a short pitch so as to face each other and overlap each other in the axial direction.

[0009] An axial force reinforcement layer 127 is provided on the outer periphery of the internal pressure reinforcement layer 125 via a seat layer 119b. The axial force reinforcement layer 127 is a reinforcement layer that mainly serves to suppress axial deformation of the flexible tube 117. The axial force reinforcement layer 127 is formed, for example, by winding a reinforcing strip having a flat cross section alternately in two layers with a long pitch via a seat layer 119c.

[0010] A protective layer 129 is provided via a seat layer 119d on the outer periphery of the axial force reinforcing layer 127. The protective layer 129 is a layer for preventing, for example, seawater or the like from penetrating into the reinforcing layer.

[0011] Such a conventional fluid transport pipe 105 can obtain extremely high internal pressure resistance characteristics while ensuring flexibility. However, such a configuration increases the weight of the fluid transport pipe. In particular, when used in deep water, the total length of the fluid transport pipe 105 becomes long, and tension due to the weight of the fluid transport pipe 105 is applied over the entire length of the fluid transport pipe 105 in the sea near the floating facility 101, so that a stronger axial force reinforcing layer 127 is required, and there is a concern that the weight of the fluid transport pipe 105 will increase further.

[0012] The present invention has been made in consideration of the above problems, and has an object to provide a fluid transport pipe that is simple in structure and lightweight. [Means for solving the problem]

[0013] In order to achieve the above-mentioned object, a first invention is a fluid transport pipe for use underwater, comprising: a flexible inner pipe; and a protective layer provided on the outer periphery of the inner pipe, the protective layer being tubular and having high strength fibers therein, the high strength fibers being integrated with a resin, the inner pipe being a flexible pipe. and the flexible tube Outer circumference To be established A resin layer is provided. Between the inner tube and the protective layer This fluid transport pipe is characterized in that it does not have a metal reinforcing layer, but has a resin intermediate layer between the inner tube and the protective layer, the intermediate layer and the protective layer are not integrated, and the protective layer is capable of sliding relative to the intermediate layer.

[0015] The hardness of the intermediate layer is desirably equal to or greater than the hardness of the protective layer.

[0016] The outer circumferential surface of the intermediate layer or the inner circumferential surface of the protective layer may be formed with projections and recesses.

[0017] A heat insulating layer may be provided on the inner peripheral surface side of the protective layer.

[0018] 1. According to the invention, the internal pressure reinforcement layer and / or the axial force reinforcement layer are integrated with the protective layer, and the internal pressure resistance and axial tensile resistance are secured by the high strength fibers, resulting in a simple and lightweight structure. In addition, because of the light weight, the required axial force is reduced, and the axial force reinforcement layer can be integrated with the protective layer. This makes it possible to obtain a fluid transport pipe that is even lighter and has a simpler structure.

[0019] Furthermore, by providing an intermediate layer between the inner tube and the protective layer that is not integrated with the protective layer, when the fluid transport tube is bent and unevenness is formed on the inner surface of the protective layer due to wrinkles, etc., the intermediate layer can suppress damage to the resin layer of the inner tube due to the unevenness of the protective layer. At this time, since the protective layer is slidable relative to the intermediate layer, the protective layer and the intermediate layer slide when the fluid transport tube is bent, and therefore a decrease in flexibility can be suppressed.

[0020] In this case, particularly if the hardness of the intermediate layer is equal to or greater than the hardness of the protective layer, the intermediate layer is prevented from being deformed by the protective layer, and damage to the inner tube can be more reliably prevented.

[0021] Furthermore, if the outer peripheral surface of the intermediate layer or the inner peripheral surface of the protective layer is uneven, the contact area between the two is reduced, and the sliding properties between the two can be improved.

[0022] Furthermore, if a heat insulating layer is provided on the inner peripheral surface side of the protective layer, freezing or the like of the outside of the fluid transport pipe can be suppressed even when an extremely low temperature fluid is transported inside. Effect of the Invention

[0023] According to the present invention, it is possible to provide a fluid transport pipe that is lightweight and has a simple structure. [Brief description of the drawings]

[0024] [Figure 1] FIG. 2 is a cross-sectional perspective view showing the fluid transport pipe 1. [Diagram 2] FIG. 2 is an axial cross-sectional view showing the fluid transport pipe 1. [Diagram 3] FIG. 2 is an axial cross-sectional view showing the fluid transport pipe 1a. [Figure 4] FIG. 3 is an axial cross-sectional view showing a fluid transport pipe 1b. [Diagram 5] FIG. 1 shows an offshore floating body system 100. [Figure 6] FIG. 1 is a cross-sectional perspective view showing a conventional fluid transport pipe 105. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] (First embodiment) A fluid transport pipe according to an embodiment of the present invention will be described below. Fig. 1 is a perspective cross-sectional view of the fluid transport pipe 1, and Fig. 2 is a circumferential cross-sectional view of the fluid transport pipe 1. The fluid transport pipe 1 is mainly used underwater and can be used for transporting liquefied carbon dioxide in addition to the above-mentioned transport of LNG, oil, etc. The fluid transport pipe 1 is mainly composed of a flexible pipe 3, a resin layer 5, a protective layer 11, etc.

[0026] The flexible tube 3 is located in the innermost layer of the fluid transport pipe 1, and is made of stainless steel, which has excellent buckling strength against external pressure and good corrosion resistance, such as an interlock pipe. In this case, the flexible tube 3 is made by forming tapes into an S-shaped cross section and connecting them by meshing with each other at the S-shaped parts, and has flexibility. Note that instead of the interlock pipe, it is also possible to use other types of pipes, such as a bellows pipe, as long as they have similar flexibility and excellent buckling strength.

[0027] A resin layer 5 is provided on the outer periphery of the flexible tube 3. The resin layer 5 blocks the fluid flowing inside the flexible tube 3. The resin layer 5 is made of a resin such as polyethylene. A seat layer 9 may be provided between the flexible tube 3 and the resin layer 5. The seat layer 9 is provided as necessary and is a layer for making the uneven shape of the outer periphery of the flexible tube 3 approximately flat, and is deformable in accordance with the flexibility of the flexible tube 3. For example, the seat layer 9 has a certain thickness, such as a nonwoven fabric, and serves as a cushion for the unevenness of the outer periphery of the flexible tube 3.

[0028] Incidentally, providing the resin layer 5 on the outer periphery of the flexible tube 3 does not necessarily mean that the flexible tube 3 and the resin layer 5 are in contact with each other, and even if another layer such as the seat layer 9 is provided between them, the resin layer 5 is said to be provided on the "outer periphery" of the flexible tube 3. This also applies to the use of the term "outer periphery" in the following description. Incidentally, the seat layer 9 is omitted from illustration in Fig. 2 and subsequent figures.

[0029] Here, the flexible tube 3 and the resin layer 5 together form the inner tube 7. If the airtightness and watertightness of the internal fluid can be ensured by the flexible tube 3 alone, the resin layer 5 is not necessary. In this way, the form of the inner tube 7 is not particularly limited as long as it is flexible, allows the fluid to flow inside, and can block the fluid from leaking out to the outside.

[0030] A protective layer 11 is provided on the outer periphery of the inner pipe 7, that is, on the outermost periphery of the fluid transport pipe 1. The protective layer 11 is a tubular member in which high-strength fibers are disposed inside a resin base material, and the resin and the high-strength fibers are integrated. For example, a polyaramid-based resin or a polyurethane-based resin can be used as the resin. For example, a polyester-based fiber or an aramid-based fiber can be used as the high-strength fiber.

[0031] Here, it is preferable that the high-strength fibers disposed inside the resin are not arranged so that their longitudinal direction faces in one direction, but are arranged, for example, in two directions, the circumferential direction and the axial direction, of the protective layer 11. For example, it is preferable to use a cloth woven in a lattice pattern from high-strength fibers.

[0032] However, since the protective layer 11 using such a high-strength fiber composite resin has a certain degree of rigidity, there is a risk of reducing the flexibility of the fluid transport pipe 1. For this reason, it is preferable that the protective layer 11 and the inner pipe 7 are not fused or bonded over their entire length, but are at least partially slidable against each other. In this way, the occurrence of sliding between the protective layer 11 and the inner pipe 7 can improve the flexibility of the fluid transport pipe 1.

[0033] Next, an outline of a manufacturing method for the fluid transport pipe 1 will be described. First, a seating tape is wrapped around a previously manufactured flexible pipe 3 as necessary to form a seating layer 9 (Fig. 1). An extruder is used to extrude and coat the outer periphery of the flexible pipe 3 on which the seating layer 9 has been formed, forming a resin layer 5, thereby forming the inner pipe 7.

[0034] Meanwhile, the high-strength fibers formed into a cylindrical shape are extrusion-coated with resin while being fed, forming a cylindrical protective layer 11. Finally, the inner tube 7 is inserted inside the protective layer 11. In this manner, the fluid transport pipe 1 is formed. That is, the inner tube 7 and the protective layer 11 are manufactured as separate bodies. Note that the protective layer 11 may also be formed by arranging high-strength fibers on the outer periphery of the inner tube 7 and directly extrusion-coating the resin.

[0035] As described above, according to this embodiment, by forming the internal pressure reinforcement layer and / or axial force reinforcement layer, which have been conventionally used, integrally with the protective layer 11, it is possible to obtain a fluid transport pipe 1 capable of ensuring internal pressure resistance characteristics and axial tensile resistance characteristics with a simple structure. In particular, by eliminating the internal pressure reinforcement layer and axial force reinforcement layer, which have been conventionally formed using metal strips, it is possible to obtain an extremely lightweight and compact fluid transport pipe 1. Thus, even if the structure is simpler than the internal pressure reinforcement layer using a conventional steel concave member or the like, it is fully applicable as long as the necessary internal pressure resistance characteristics are ensured, for example, when used to transport liquefied carbon dioxide, which liquefies at a pressure of about 5 MPa even at room temperature.

[0036] In this case, the protective layer 11 has a higher rigidity than the protective layers of conventional fluid transport pipes, but by making the inner pipe 7 and the protective layer 11 separate and not completely integrated by fusion or the like, the flexibility of the fluid transport pipe 1 can be ensured.

[0037] Second embodiment Next, a second embodiment will be described. Fig. 3(a) is a cross-sectional view showing a fluid transport pipe 1a according to the second embodiment. In the following description, components having the same functions as those of the fluid transport pipe 1 are given the same reference numerals as those in Figs. 1 and 2, and duplicated descriptions will be omitted.

[0038] The fluid transport pipe 1a has a configuration substantially similar to that of the fluid transport pipe 1, but differs in that an intermediate layer 13 is formed on the outer periphery of the inner pipe 7. That is, in the fluid transport pipe 1a, the intermediate layer 13 is provided between the inner pipe 7 and the protective layer 11. As described above, the protective layer 11 is also provided on the outer periphery of the inner pipe 7 in this case.

[0039] The intermediate layer 13 may be made of metal or resin, but desirably has a hardness equal to or greater than the hardness (Shore D hardness) of the resin constituting the protective layer 11. For example, the intermediate layer 13 is desirably made of a resin having a hardness higher than that of the resin constituting the protective layer 11. Note that a fiber reinforcing tape or the like may be wound between the intermediate layer 13 and the inner tube 7 for further reinforcement. Moreover, the intermediate layer 13 itself may be made of a high-strength fiber composite resin instead of a solid resin.

[0040] For example, the intermediate layer 13 is formed by extruding the resin layer 5 of the inner tube 7 and then extruding the intermediate layer 13 on the outer periphery of the resin layer 5. Alternatively, the intermediate layer 13 may be formed by wrapping a tape-like intermediate layer 13 around the outer periphery of the resin layer 5. Meanwhile, as described above, the intermediate layer 13 and the protective layer 11 are not integrated with each other, and the protective layer 11 is slidable relative to the intermediate layer 13.

[0041] Here, as shown in FIG. 3(b), an uneven shape may be formed on the outer peripheral surface of the intermediate layer 13 (the surface facing the protective layer 11). By doing so, the contact area between the intermediate layer 13 and the protective layer 11 is reduced, and the insertion resistance when inserting the intermediate layer 13 (inner tube 7) into the cylindrical protective layer 11 can be reduced. In addition, the sliding property between the two can be improved. Incidentally, the unevenness may be formed on the inner peripheral surface of the protective layer 11, instead of the outer peripheral surface of the intermediate layer 13. The uneven shape may be formed by a die during extrusion molding, or a separate uneven processing may be performed after extrusion molding.

[0042] As described above, when the fluid transport pipe 1a is bent, sliding occurs between the intermediate layer 13 and the protective layer 11, so that a decrease in flexibility can be suppressed. On the other hand, when the protective layer 11 is bent, unevenness due to wrinkles or the like may be formed on the inner surface of the protective layer 11. In such a case, the presence of the intermediate layer 13 inside the protective layer 11 can suppress the unevenness of the protective layer 11 from coming into contact with the inner pipe 7 and damaging the inner pipe 7. In other words, the intermediate layer 13 functions to protect the inner pipe 7 from the protective layer 11.

[0043] As described above, according to the second embodiment, it is possible to obtain the same effects as those of the first embodiment. In addition, by providing the intermediate layer 13 between the protective layer 11 and the inner pipe 7, it is possible to prevent the inner pipe 7 from being damaged by the uneven shape of the inner surface that occurs when the protective layer 11 is bent.

[0044] In this case, by making the hardness of the intermediate layer 13 equal to or greater than that of the protective layer 11, deformation of the intermediate layer 13 by the protective layer 11 can be suppressed.

[0045] Furthermore, by forming an uneven shape on either of the opposing surfaces of the intermediate layer 13 and the protective layer 11, the contact area between the intermediate layer 13 and the protective layer 11 can be reduced, thereby improving the sliding property between them. As a result, the flexibility of the fluid transport pipe 1a can be improved.

[0046] Third embodiment Next, a third embodiment will be described. Fig. 4 is a cross-sectional view showing a fluid transport pipe 1b according to the third embodiment. The fluid transport pipe 1b has a configuration substantially similar to that of the fluid transport pipe 1a, but differs in that a heat insulating layer 15 is provided between the intermediate layer 13 and the protective layer 11. As described above, the protective layer 11 is also provided on the outer periphery of the inner pipe 7 in this case.

[0047] The heat insulating layer 15 is made of, for example, foamed resin, glass wool, etc. Note that the intermediate layer 13 may be inserted into the cylindrical protective layer 11 with a heat insulating material disposed on the outer periphery of the intermediate layer 13, or the protective layer 11 and the heat insulating layer 15 may be integrally formed into a cylindrical shape, and the intermediate layer 13 (inner tube 7) may be inserted into the cylindrical shape.

[0048] According to the third embodiment, it is possible to obtain the same effects as those of the first embodiment. In addition, by providing the heat insulating layer 15 on the inner periphery side of the protective layer 11, it is possible to suppress freezing of the outer surface of the protective layer 11 even when transporting a low-temperature fluid.

[0049] Although the embodiment of the present invention has been described above with reference to the attached drawings, the technical scope of the present invention is not limited to the above-described embodiment. It is clear that a person skilled in the art can think of various modifications or alterations within the scope of the technical ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present invention.

[0050] For example, it goes without saying that each embodiment can be combined with each other. For example, in the second embodiment, an example in which an uneven shape is formed on the opposing surfaces of the intermediate layer 13 and the protective layer 11 has been described, but even if the intermediate layer 13 is not formed, an uneven shape may be formed on one of the opposing surfaces of the inner pipe 7 and the protective layer 11. Also, in the third embodiment, a cylindrical member in which the heat insulating layer 15 is sandwiched between the protective layer 11 and the intermediate layer 13 may be integrally formed, and a separate inner pipe 7 may be inserted inside this. The heat insulating layer 15 may be provided directly on the outer periphery of the inner pipe 7 . [Explanation of symbols]

[0051] 1, 1a, 1b……Fluid transport pipe 3...Flexible tube 5: Resin layer 7……Inner pipe 9……Zatoko layer 11……Protective layer 13. Middle class 15....Thermal insulation layer 100………Offshore floating system 101....Floating facility 105……Fluid transport pipe 109……Undersea 111……Mooring cable 117...Flexible tube 119a, 119b, 119c, 119d...Zatoko layer 121...Resin layer 125………Internal pressure reinforcement layer 127...Axial reinforcement layer 129……Protective layer

Claims

1. A fluid transport pipe for use underwater, comprising: A flexible inner tube; a protective layer provided on the outer periphery of the inner tube; Equipped with The protective layer is tubular and has high-strength fibers therein, the high-strength fibers being integrated with a resin, the inner tube has a flexible tube and a resin layer provided on an outer periphery of the flexible tube, a metal reinforcing layer is not provided between the inner tube and the protective layer, and a resin intermediate layer is provided between the inner tube and the protective layer; A fluid transport pipe, wherein the intermediate layer and the protective layer are not integrated, and the protective layer is slidable relative to the intermediate layer.

2. 2. The fluid transport pipe according to claim 1, wherein the intermediate layer has a hardness equal to or greater than a hardness of the protective layer.

3. 3. The fluid transport pipe according to claim 1, wherein an uneven shape is formed on an outer circumferential surface of the intermediate layer or an inner circumferential surface of the protective layer.

4. 4. The fluid transport pipe according to claim 1, further comprising a heat insulating layer provided on an inner peripheral surface side of the protective layer.

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