Field repair joint for submarine cable and submarine cable restraining method thereof

Abstract

The present invention relates to a field repair joint and, more specifically, to a field repair joint capable of easily and quickly repairing a submarine cable at sea, preventing separation of the submarine cable, and securely restraining the submarine cable. A field repair joint, according to one embodiment of the present invention, comprises: a cylindrical outer case having a hollow interior; and flanges configured to be coupled to both ends of the outer case, respectively, wherein the flanges comprise: a plate-shaped first part which is arranged inside the outer case and has a first through hole formed therein; and a second part which comprises a cylindrical base portion having a second through hole, and a first ring portion disposed at one end of the base portion and facing the first part; and a horn-shaped third part which has a volume to be disposed inside the second through hole, has a third through hole, and is received inside the second through hole by means of the first part.

Description

Field recovery joint for submarine cables and method for restraining submarine cables therefor

[0001] The present invention relates to a field recovery joint for a submarine cable and a method for restraining a submarine cable thereof, and more particularly, to a field recovery joint for a submarine cable and a method for restraining a submarine cable thereof, which can easily and quickly restore a submarine cable at sea, prevent the submarine cable from falling off due to a load, and stably restrain a submarine cable.

[0002] A submarine cable is a cable installed on the seabed to transmit electricity between two points across the sea.

[0003] For submarine cables, it is very important to ensure a strong connection between cables and watertightness of the joints at the time of initial installation, and to perform rapid and economical maintenance in case of damage to the cables due to seawater flow caused by climate change, special fishing gear caused by fishing activities, or anchors of anchored fishing vessels.

[0004] When installing submarine cables for the first time, i.e. when the communication connection is for a short distance, a single-strand cable can be laid directly on the seabed, allowing both ends to be connected to each communication means. However, when connecting areas separated by a distance of more than 10 kilometers, installation using a single-strand cable alone is impossible. Therefore, two or more cables are connected using a connecting device and laid on the seabed. Furthermore, if a submarine cable laid on the seabed as described above is damaged due to severe climate change or fishing activities, the cable is towed onto a ship, the damaged portion is cut, and a spare cable is placed in the center, and the damaged portion is connected using a connecting device on both sides. This process is then used to repair the damaged portion of the submarine cable.

[0005] The key technology for submarine cable connection devices is to maintain a secure connection without deformation due to tensile stress after connection to the submarine cable, while ensuring watertightness within the connection device, even over long periods of use. Furthermore, convenience must be guaranteed for assembly and installation, as well as for mobile installation, during the connection process.

[0006] While submarine cables have an average lifespan of approximately 20 to 25 years, they can be damaged by unforeseen circumstances on the ocean floor. Damaged submarine cables can be repaired onboard ships using field repair joints.

[0007] When a damaged submarine cable is repaired and installed at sea in a field repair joint, the self-weight of the submarine cable exerts a load on both ends of the field repair joint. To prevent the cable from detaching due to this load, a restraining device has been used to secure the submarine cable to the field repair joint.

[0008] [Prior Art Literature]

[0009] [Patent Document]

[0010] (Patent Document 1) Republic of Korea Publication No. 10-2014-0115509 (October 1, 2014)

[0011] The problem to be solved by the present invention is to provide a field recovery joint for a submarine cable and a method for restraining a submarine cable thereof, which can prevent the submarine cable from falling off due to its own weight.

[0012] In addition, the present invention provides a field recovery joint for a submarine cable capable of stably restraining an installed submarine cable and a method for restraining a submarine cable thereof.

[0013] In addition, the present invention provides a field recovery joint for a submarine cable capable of preventing the infiltration of moisture such as seawater from the outside to the inside, and a method for restraining the submarine cable thereof.

[0014] According to one embodiment of the present invention, a field recovery joint comprises: a cylindrical outer case having an interior that is hollow; and a flange configured to be coupled to each end of the outer case; wherein the flange comprises: a first part in the shape of a plate disposed inside the outer case and having a first through hole formed therein; a second part including a cylindrical base portion having a second through hole and a first ring portion disposed at one end of the base portion and arranged to face the first part; and a third part in the shape of a cone having a volume that can be disposed inside the second through hole, having a third through hole, and being received inside the second through hole by the first part.

[0015] According to another embodiment of the present invention, a field recovery joint comprises: a cylindrical outer case; and a flange configured to be coupled to openings at both ends of the outer case; wherein the flange comprises a circular plate, a cylindrical portion, and a truncated cone for fixing a plurality of steel wires of the submarine cable, wherein the circular plate, the cylindrical portion, and the truncated cone each have a through hole into which the submarine cable can be inserted, the truncated cone is disposed within the through hole of the cylindrical portion through one side opening of the cylindrical portion, and the circular plate is disposed to block the one side opening of the cylindrical portion, and a portion of the plurality of steel wires of the submarine cable is configured to be inserted between an inner surface of the cylindrical portion defining the through hole of the cylindrical portion and an outer surface of the truncated cone, and another portion of the plurality of steel wires of the submarine cable is configured to be inserted between one end of the cylindrical portion and the circular plate.

[0016] According to another embodiment of the present invention, a method is provided for securing a submarine cable comprising a plurality of steel wires and an outer covering layer surrounding the plurality of steel wires to a field repair joint of claim 1, comprising the steps of: removing the outer covering layer at an end of the submarine cable to expose the plurality of steel wires to the outside; passing the submarine cable through a second through hole of the second part and then bending the plurality of steel wires outward; passing the submarine cable through a third through hole of the third part and then inserting the third part into the second through hole, such that the plurality of steel wires are sandwiched between the second part and the third part; passing the submarine cable through a first through hole of the first part and then pressing the first part toward a first ring portion of the second part; joining the first part and the first ring portion through a fastening means to bring the first part into maximum contact with the first ring portion, such that the plurality of steel wires are sandwiched between the first part and the first ring portion; A step of cutting off the ends exposed to the outside of the plurality of steel wires sandwiched between the first part and the first ring part; and a step of injecting and hardening a liquid compound into an injection hole connected to the second through hole of the base part.

[0017] By using the on-site recovery joint for a submarine cable and the submarine cable restraint method thereof according to the present invention, it is possible to prevent the submarine cable from falling off due to its own weight.

[0018] Additionally, it can stably restrain installed submarine cables.

[0019] Additionally, it can prevent moisture such as seawater from penetrating from the outside to the inside.

[0020] FIG. 1 (a) and (b) are drawings illustrating examples of submarine cables that can be installed in a field recovery connection box according to one embodiment of the present invention.

[0021] FIG. 2 is a perspective view of a field repair joint according to one embodiment of the present invention capable of repairing or restoring a submarine cable illustrated in FIG. 1 on a ship at sea.

[0022] FIG. 3 is an enlarged perspective view of a portion of a field recovery connection box according to one embodiment of the present invention illustrated in FIG. 2.

[0023] Figure 4 is an exploded perspective view of only the first flange (300a) illustrated in Figure 3.

[0024] Figure 5 is a cross-sectional perspective view of the second part (330) and the third part (350) illustrated in Figure 4 combined.

[0025] Figure 6 is an enlarged view of A in Figure 5.

[0026] FIG. 7 is a perspective view of the end portion of the submarine cable shown in (b) of FIG. 1 for coupling to the first flange (300a) shown in FIGS. 2 to 6.

[0027] FIGS. 8 to 13 are drawings for explaining a method of binding the submarine cable illustrated in FIG. 7 to the first flange (300a) illustrated in FIGS. 2 to 6.

[0028] FIG. 14 is a conceptual diagram showing a state in which a submarine cable is restored inside a field restoration connection box according to one embodiment of the present invention illustrated in FIG. 2.

[0029] The detailed description of the present invention, which follows, refers to the accompanying drawings, which illustrate specific embodiments in which the present invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present invention. It should be understood that the various embodiments of the present invention, while different from each other, are not necessarily mutually exclusive.

[0030] There are two types of submarine cables: alternating current (AC) submarine cables and direct current (DC) submarine cables.

[0031] AC submarine cables are primarily used for medium- to long-distance applications (up to 100 km) due to their advantage of not incurring additional costs when connected to existing underground systems. They can be used as either three-core or single-core submarine cables. XLPE insulation is typically used, and XLPE-insulated cables are widely used for submarine cables due to their ease of installation and maintenance, ease of connection and repair, and excellent chemical and electrical properties.

[0032] DC submarine cables have lower peak voltages than AC cables, allowing for thinner insulation, resulting in lower costs. Unlike AC cables, they are free from frequency-related losses (such as sheath loss and dielectric loss). Furthermore, they can be interconnected with other power systems operating at different frequencies and voltages, offering the advantage of eliminating electrical and technical constraints when interconnecting internationally.

[0033] Below, with reference to Fig. 1, the structure of a submarine cable will be examined.

[0034] FIG. 1 (a) and (b) are drawings illustrating examples of submarine cables that can be installed in a field repair joint (FRJ) according to one embodiment of the present invention.

[0035] The submarine cable illustrated in (a) of Fig. 1 is an example of a direct current submarine cable.

[0036] Referring to (a) of Fig. 1, a direct current submarine cable includes a conductor (10), an inner semiconducting layer (12), an insulating layer (14), an outer semiconducting layer (16), a steel wire layer (18), and an outer sheath layer (20).

[0037] A conductor (10) is placed in the center and acts as a passage through which current flows. For example, the conductor (10) is made of copper or aluminum. The conductor (10) may also be made of multiple strands.

[0038] The inner semiconducting layer (12) surrounds the conductor (10), and evenly distributes the charge on the conductor surface to uniformly form an electric field, thereby improving the dielectric strength of the insulating layer (14) described below. Furthermore, it prevents the formation of a gap between the conductor (10) and the insulating layer (14), thereby preventing corona discharge and ionization. In addition, the inner semiconducting layer (12) also plays a role in preventing the penetration of the insulating layer (14) into the conductor (10) during the manufacture of the DC submarine cable.

[0039] The insulating layer (14) surrounds the inner semiconducting layer (12) and electrically insulates the conductor (10) from the outside. The insulating layer (14) may be made of a material such as, for example, XLPE (Cross-linked Polyethylene).

[0040] The outer semiconducting layer (16) surrounds the insulating layer (14) and serves to improve the dielectric strength of the insulating layer (14) by making the distribution of electric field lines between it and the inner semiconducting layer (12) equipotential.

[0041] On the outside of the outer semiconducting layer (16), a shielding layer (not shown) made of a metal sheath or a steel wire layer (18) is provided depending on the type of cable. The shielding layer or steel wire layer (18) is provided for electrical shielding and return of short-circuit current.

[0042] The outermost layer of a direct current submarine cable is provided with an outer sheath (20). The outer sheath (20) serves to protect the components located on the inner side. The outer sheath (20) is composed of a material with excellent weather resistance to withstand various climates including light, wind, rain, moisture, and gases in the air, chemical resistance to withstand chemicals, and mechanical strength. For example, it can be made of PVC (Polyvinyl chloride) or PE (Polyethylene).

[0043] The submarine cable illustrated in (b) of Fig. 1 is an example of an AC submarine cable.

[0044] Referring to (b) of Fig. 1, the AC submarine cable includes three internal cables and an optical cable (30).

[0045] Each of the above inner cables includes a conductor (10), an inner semiconducting layer (12), an insulating layer (14), an outer semiconducting layer (15), a metal sheath layer (17), and a shielding layer (19). In addition, it further includes a bedding layer (21) surrounding three inner cables and an optical cable (30), a plurality of steel wires (18) surrounding the bedding layer (21), and an outer sheath layer (20) surrounding the plurality of steel wires (18).

[0046] A field recovery joint box according to one embodiment of the present invention is a joint box for reconnecting a faulty submarine cable at sea when a fault occurs in the submarine cable installed at sea, as shown in Fig. 1 (a) or (b). This field recovery joint box can prevent shear force on the connecting material by fixing axial stress generated by loads generated during installation. Compared to conventional ground-based joint boxes, this joint box is designed for connecting submarine cables at sea where the installation environment and external conditions are unfavorable.

[0047] Hereinafter, with reference to FIGS. 2 to 14, a field recovery connection box according to one embodiment of the present invention will be examined.

[0048] FIG. 2 is a perspective view of a field repair joint according to one embodiment of the present invention capable of repairing or restoring a submarine cable illustrated in FIG. 1 on a ship at sea.

[0049] Referring to FIG. 2, a field recovery connection box according to one embodiment of the present invention includes an outer case (100) and a flange (300).

[0050] The outer case (100) has a hollow cylinder shape. For example, the outer case (100) may be cylindrical, polygonal, or oval. In the drawing, it is typically depicted as cylindrical. Both ends of the outer case (100) are open, and flanges (300) are connected to each end.

[0051] The outer case (100) is a device that can withstand mechanical stress caused by external force, and may not have a waterproof function itself.

[0052] The outer case (100) includes a plurality of outer cases (100a, 100b, 100c, 100d). For example, the outer case (100) may be composed of four first to fourth outer cases (100a, 100b, 100c, 100d). The first to fourth outer cases (100a, 100b, 100c, 100d) may be combined to form a cylindrical outer case (100).

[0053] A third external case (100c) may be placed on one side of the first external case (100a), a fourth external case (100d) may be placed on one side of the second external case (100b), a second external case (100b) may be placed under the first external case (100a), and a fourth external case (100b) may be placed under the third external case (100c). These may be firmly fastened to each other using fastening means such as bolts and nuts.

[0054] When the outer case (100) is composed of first to fourth outer cases (100a, 100b, 100c, 100d), it is easy to enclose the repaired submarine cable with the first to fourth outer cases (100a, 100b, 100c, 100d) after electrically and physically connecting the damaged or cut submarine cable. Therefore, the repair of the submarine cable can be completed quickly and easily.

[0055] The material of the outer case (100) can be composed of a material that can alleviate or prevent rust and withstand high external water pressure on the seabed.

[0056] A flange (300) is connected to each end of a cylindrical outer case (100). The flange (300) includes a first flange (300a) connected to one end of the outer case (100) and a second flange (300b) connected to the other end of the outer case (100).

[0057] A submarine cable is firmly and stably fastened to each of the first and second flanges (300a, 300b). The end of the first submarine cable is fastened to the first flange (300a), and the end of the second submarine cable is fastened to the flange (300b). Here, the first submarine cable and the second submarine cable may be different submarine cables. Alternatively, the first submarine cable and the second submarine cable may have originally been one submarine cable, but a portion thereof was separated by an external force, thereby splitting the cable into two.

[0058] Referring to FIGS. 3 to 6, the detailed configuration of each flange (300) will be examined. Here, since the first flange (300a) and the second flange (300b) are identical to each other, only the first flange (300a) will be described below, and the second flange (300b) will be replaced with the description of the first flange (300a).

[0059] FIG. 3 is an enlarged perspective view of a portion of a field recovery connection box according to an embodiment of the present invention illustrated in FIG. 2, FIG. 4 is an exploded perspective view of only the first flange (300a) illustrated in FIG. 3, FIG. 5 is a cross-sectional perspective view of the second part (330) and the third part (350) illustrated in FIG. 4 combined, and FIG. 6 is an enlarged view of A of FIG. 5.

[0060] Referring to FIGS. 2 to 6, the first flange (300a) includes a first part (310), a second part (330), and a third part (350).

[0061] The first part (310) has a plate shape with a first through hole (310h) formed in the center. Here, the plate may be a circular plate. The submarine cable illustrated in FIG. 1 may be placed in the first through hole (310h). The cross-sectional shape of the first through hole (310h) may be circular, corresponding to the outer shape of the submarine cable.

[0062] The first part (310) is placed inside the outer case (100). The first part (310) may have a shape and size corresponding to the inner diameter of the outer case.

[0063] A plurality of fastening holes (310B) are formed at the edge of the first part (310). A fastening means, such as a bolt inserted into the fastening hole (333B) of the first ring portion (333) of the second part (330), can be placed in the fastening holes (310B).

[0064] The second part (330) includes a base portion (331), a first ring portion (333), a second ring portion (335), and a third ring portion (337).

[0065] The base portion (331) has a second through hole (330h) into which the submarine cable illustrated in Fig. 1 can be placed. The cross-sectional shape of the second through hole (330h) may be circular, corresponding to the outer shape of the submarine cable.

[0066] The base portion (331) may have a cylindrical shape.

[0067] The base portion (331) has one or more injection holes (331j1, 331j2) connected to the second through hole (330h). The injection holes (331j1, 331j2) are holes used for injecting a liquid waterproofing compound. The liquid compound fills the space or gap between the first flange (300a) and the submarine cable after the submarine cable illustrated in FIG. 1 is joined to the first flange (300a). The liquid compound hardens over time, thereby preventing moisture from penetrating into the space or gap between the first flange (300a) and the submarine cable.

[0068] The first ring portion (333) is arranged at one end of the base portion (331) and is arranged to face the first part (310). The first ring portion (333) has a width or diameter greater than that of the base portion (331). The first ring portion (333) is arranged inside the outer case (100) together with the first part (310). The first ring portion (333) has a shape corresponding to the outer surface shape of the base portion (331). If the base portion (331) is cylindrical, the first ring portion (333) has a circular ring shape.

[0069] A plurality of fastening holes (333B) are formed at the edge of the first ring portion (333). A fastening means, such as a bolt inserted into the fastening hole (310B) of the first part (310), can be positioned through the fastening holes (333B).

[0070] The second ring portion (335) is positioned in the middle between one end and the other end of the base portion (331) and has a larger width or diameter than the first ring portion (333) and the third ring portion (335).

[0071] The second ring portion (335) is directly connected to the outer case (100). The second ring portion (335) and the outer case (100) can be connected to each other through connecting means such as bolts and nuts. A plurality of connecting holes (335B) are formed at the edge of the second ring portion (335). Connecting means such as bolts inserted into the connecting holes of the outer case (100) can be positioned by passing through the connecting holes (335B).

[0072] The third ring portion (337) is placed at the other end of the base portion (331). The third ring portion (337) has a width or diameter greater than that of the base portion (331).

[0073] The third ring portion (337), although not shown in the drawing, may be connected to a bend adjuster (not shown) that adjusts the degree of bending of the submarine cable. The bend adjuster (not shown) may be connected to a bend stiffener or a bend restrictor. The third ring portion (337) and the bend adjuster (not shown) may be connected to each other through a connecting means such as bolts and nuts. A plurality of connecting holes (337B) are formed at the edge of the third ring portion (337). A connecting means such as a bolt inserted into the connecting hole of the bend adjuster (not shown) may be arranged to pass through the connecting holes (337B).

[0074] The third part (350) is placed inside the second through hole (330h) of the second part (330). The third part (350) may be placed inside one end of the base portion (331) of the second part (330).

[0075] The third part (350) has a horn shape. Here, the horn may be a truncated cone.

[0076] The third part (350) has a third through hole (350h) into which the submarine cable illustrated in Fig. 1 can be placed. The diameter of the third through hole (350h) is constant, but smaller than the diameter of the second through hole (330h) of the base portion (331).

[0077] The thickness of one end of the base portion (331) surrounding the third part (350) becomes thicker as it goes from the first ring portion (333) toward the second ring portion (335). This shape prevents the third part (350) in the shape of a horn from escaping through the second through hole (330h) of the second part (330) when it is inserted into the second through hole (330h) of the second part (330).

[0078] The third part (350) has a shape corresponding to the internal space of one end of the base part (331), but its volume is smaller than the volume of the internal space. Accordingly, a predetermined gap (G) is formed between the inner surface of the base part (331) of the second part (330) and the outer surface of the third part (350). A plurality of steel wires (18) of the submarine cable illustrated in FIG. 1 are arranged in the gap (G).

[0079] FIG. 7 is a perspective view of the end portion of the submarine cable shown in (b) of FIG. 1 for coupling to the first flange (300a) shown in FIGS. 2 to 6.

[0080] Referring to FIG. 7, when the outer layer (20) of the terminal portion of the submarine cable shown in FIG. 1 (b) is removed, a plurality of steel wires (18) are exposed, and when the terminals of the plurality of steel wires (18) are removed, the bedding layer (21) is exposed to the outside, and when the terminal of the bedding layer (21) is removed, the insulation layer (19) of the inner cable is exposed.

[0081] FIGS. 8 to 13 are drawings for explaining a method of binding the submarine cable illustrated in FIG. 7 to the first flange (300a) illustrated in FIGS. 2 to 6.

[0082] Referring to Fig. 8, the terminal portion of the submarine cable is passed through the through hole (330h, see Fig. 4) of the second part (330), so that the second part (330) is positioned on the outer layer (20) of the submarine cable. Then, each of the exposed steel wires (18) is bent outward. The bent steel wires (18) are arranged in a radial shape.

[0083] Next, referring to Fig. 9, the third part (350) is inserted into the terminal portion of the submarine cable, and then the first part (310) is similarly inserted into the terminal portion of the submarine cable. The third part (350) and the first part (310) are positioned on the bedding layer (21) of the submarine cable.

[0084] Next, referring to FIG. 10, the third part (350) and the first part (310) are pushed toward the second part (330), so that the third part (350) enters the base part (331) of the second part (330), and the first part (310) approaches the first ring part (333) of the second part (330).

[0085] When the first part (310) comes somewhat close to the first ring portion (333) of the second part (330), the bolt (510B) is sequentially inserted into the fastening hole (310B) of the first part (310) and the fastening hole (333B) of the second part (330), and a nut (not shown) is fastened to the end of the bolt (510B). Bolts (510B) are also inserted into other fastening holes, and nuts (not shown) are fastened.

[0086] Next, referring to FIG. 11, each bolt (510B) and nut (510N) are tightened as much as possible so that the first part (310) is as close as possible to the first ring portion (333) of the second part (330). The steel wires (18) are tightly fitted and arranged between the first part (310) and the second part (330).

[0087] Next, referring to Fig. 12, the portion exposed to the outside of each steel wire (18) is cut off as much as possible. Meanwhile, a shield (700) may be further placed to block the gap between the first part (310) and the bedding layer (21) of the submarine cable.

[0088] Next, referring to FIG. 13, a liquid compound (900) is injected into the injection holes (331j1, 331j2) formed in the base portion (331) of the second part (330). The liquid compound (900) has adhesive properties upon curing and is intended to strengthen the bonding strength (mechanical performance) with other components in contact. The liquid compound (900) can be injected into the injection holes (331j1, 331j2) using a funnel (950). The liquid compound (900) being injected can fill the gaps and spaces between the steel wires (18) of the submarine cable inside the second through hole (330h) of the second part (330), the gap (G) between the second part (330) and the third part (350) where the steel wires (18) are inserted, and the gaps and spaces between the first part (310) and the second part (330) where the steel wires (18) are inserted. Thereafter, when the liquid compound (900) hardens, it shrinks and improves the bonding strength with the steel wires (18) of the submarine cable.

[0089] Meanwhile, in order to block the gap between the second part (330) and the outer layer (20) of the submarine cable, an additional shielding plate (750) can be placed.

[0090] FIG. 14 is a conceptual diagram showing a state in which a submarine cable is restored inside a field restoration connection box according to one embodiment of the present invention illustrated in FIG. 2.

[0091] Referring to FIG. 14, an internal cable (1a) on one side and an internal cable (1b) on the other side are electrically and physically connected inside an inner case (1900), and an optical cable (30a) on one side and an optical cable (30b) on the other side are electrically and physically connected inside an optical connection box (3000).

[0092] Three internal cables (1a) and one optical cable (30a) arranged on one side are included in one submarine cable (or first submarine cable), and three internal cables (1b) and one optical cable (30b) arranged on the other side are included in another submarine cable (or second submarine cable).

[0093] Inside the inner case (1900), the conductor of one side of the inner cable (1a) and the conductor of the other side of the inner cable (1b) are electrically and physically connected to each other.

[0094] The inner case (1900) may be structured to be separated into at least two or more parts and may be made of copper. The inner case (1900) may be waterproofed through lead.

[0095] The inner case (1900) may be taped to the outside with multiple tapes.

[0096] The optical connection enclosure (3000) may include an inner enclosure made of a resin material and an outer enclosure made of a metal material. The optical connection enclosure (3000) uses a double enclosure to stably electrically and physically connect optical cables to each other and prevent moisture penetration from the outside. Within the inner enclosure, an optical cable (30a) on one side and an optical cable (30b) on the other side may be electrically connected to each other.

[0097] The optical connection box (300) can be taped to the outside with multiple tapes.

[0098] The inside of the outer case (100d, 100b) may be filled with a compound (CP) for waterproofing. The compound (CP) may be a polyurethane compound rather than an epoxy compound. Epoxy materials have the disadvantages of being weaker against pressure than polyurethane materials, of being more prone to cracking, and of requiring a long installation time. The field recovery joint box according to the embodiment of the present invention is subjected to high pressure underwater, has a high possibility of moisture infiltrating inside when cracks occur, and of requiring as fast installation as possible at sea, so the compound (CP) is preferably made of polyurethane. The polyurethane compound (CP) may be manufactured through performance tests of various material properties (pressure, strength, and contact force) according to special environments such as underwater.

[0099] By using the field recovery joint according to one embodiment of the present invention illustrated in FIGS. 2 to 14 described above, when damage or an accident occurs to a submarine cable, the damaged submarine cable can be quickly and easily recovered or repaired on board a ship at sea (laying ship or recovery ship).

[0100] Furthermore, the submarine cable connected to the field recovery joint according to an embodiment of the present invention can withstand axial stress due to the cable's own weight when installed at sea. In particular, it can withstand various external forces generated when the field recovery joint is lowered into the sea by a crane after being installed on board a ship.

[0101] Additionally, the field recovery joint according to an embodiment of the present invention can prevent moisture infiltration into the interior due to external water pressure according to seawater depth. In particular, to prevent moisture infiltration due to the external water pressure, a compound with excellent interfacial contact strength can be injected into the interior of the field recovery joint to prevent moisture infiltration.

[0102] Additionally, the field recovery joint according to an embodiment of the present invention can maintain its submerged state in the sea for a long period of time, at least 20 years. In particular, rust on the exterior can be prevented as long as no significant electrical moisture infiltration occurs.

[0103] Although the embodiments of the present invention have been described with reference to the attached drawings, these are merely examples and are not intended to limit the present invention. Those skilled in the art to which the present invention pertains will appreciate that various modifications and applications not exemplified above are possible without departing from the essential characteristics of the present embodiment. For example, each component specifically shown in the embodiments can be modified and implemented. In addition, differences related to such modifications and applications should be interpreted as being included in the scope of the present invention defined in the appended claims.

[0104] [Explanation of symbols]

[0105] 100: External case

[0106] 300: Flange

Claims

1. Including an outer case having a hollow interior and a cylindrical shape; and a flange configured to be coupled to each end of the outer case; The above flange, A first part in the shape of a plate, which is placed inside the outer case and has a first through hole formed therein; A second part including a cylindrical base portion having a second through hole and a first ring portion disposed at one end of the base portion and facing the first part; and A third part having a cone shape that has a volume that can be placed inside the second through hole, has a third through hole, and is accommodated inside the second through hole by the first part; On-site recovery access point, including:

2. In paragraph 1, The above outer case includes first to fourth outer cases coupled to each other, The second outer case is placed under the first outer case, The fourth outer case is placed under the third outer case, A field recovery connection box, wherein the third external case is placed on one side of the first external case.

3. In paragraph 1, A field recovery connection box in which the first part and the first ring portion are connected through a plurality of fastening means.

4. In paragraph 1, When the first part is joined to the first ring portion, the third part is placed inside one end of the base portion, The thickness of one end of the above base portion becomes thicker as it goes from one end of the above base portion to the other end, and is a field repair connection box.

5. In paragraph 4, A field repair connection box in which, when the first part is joined to the first ring portion, the third part is sealed inside the second through hole, and a predetermined gap is formed between the third part and the base portion.

6. In paragraph 1, The above base portion has at least one injection hole connected to the second through hole and into which a liquid compound can be injected, The above liquid compound is a field repair joint for improving the bonding strength between multiple steel wires of a submarine cable.

7. In paragraph 1, The second part is a second ring part arranged in the middle of the base part and coupled with the outer case; and A third ring part arranged at the other end of the base part and coupled with a bending adjuster configured to adjust the degree of bending of the submarine cable; Field recovery access point including.

8. In paragraph 7, The width or diameter of the second ring portion is larger than the width or diameter of the first part and the first ring portion, and is a field repair connection.

9. A cylindrical outer case; and a flange configured to be coupled to the openings at both ends of the outer case; The above flange includes a disc, a cylindrical portion and a cone for fixing a plurality of steel wires of the above submarine cable, Each of the above-mentioned disc, the above-mentioned cylindrical portion and the above-mentioned truncated cone has a through hole into which the above-mentioned submarine cable can be inserted, The above cone is placed inside the through hole of the cylindrical portion through one side opening of the cylindrical portion, The above plate is positioned to block one side opening of the above cylindrical portion, A portion of a plurality of steel wires of the submarine cable is configured to be sandwiched between the inner surface of the cylindrical portion defining a through hole of the cylindrical portion and the outer surface of the truncated cone, A field repair joint configured such that another portion of a plurality of steel wires of the above submarine cable is fitted between one end of the cylindrical portion and the disc.

10. In paragraph 9, The above outer case includes first to fourth outer cases having a semi-cylindrical shape, The second outer case is placed under the first outer case, The fourth outer case is placed under the third outer case, A field recovery connection box, wherein the third external case is placed on one side of the first external case.

11. In paragraph 9, A field repair joint in which the above-mentioned plate and one end of the above-mentioned cylindrical portion are joined through a plurality of fastening means.

12. In paragraph 9, The thickness of the cylindrical portion surrounding the cone becomes thicker from one opening of the cylindrical portion to the other opening, which is a field repair connection box.

13. In paragraph 9, The cylindrical portion has at least one injection hole connected to the through hole of the cylindrical portion and into which a liquid compound can be injected, The above liquid compound is a field repair joint for improving the bonding strength between multiple steel wires of the above submarine cable.

14. In paragraph 8, A first ring portion arranged on one side of the opening of the cylindrical portion; A second ring portion disposed between one side opening and the other side opening of the cylindrical portion and coupled with the outer case; and A third ring portion arranged on the other side of the opening of the cylindrical portion and coupled with a bending adjuster configured to adjust the degree of bending of the submarine cable; Field recovery access point including.

15. In paragraph 14, The diameter of the second ring portion is larger than the diameters of the first part and the first ring portion, and is a field repair connection.

16. A method for securing a submarine cable comprising a plurality of steel wires and an outer layer surrounding the plurality of steel wires to a field recovery joint of claim 1, A step of removing the outer layer of the terminal of the submarine cable to expose the plurality of steel wires to the outside; A step of passing the submarine cable through the second through hole of the second part and then bending the plurality of steel wires outward; A step of passing the submarine cable through the third through hole of the third part and then inserting the third part into the second through hole, so that the plurality of steel wires are sandwiched between the second part and the third part; A step of passing the submarine cable through the first through hole of the first part and then pressurizing the first part toward the first ring portion of the second part; A step of joining the first part and the first ring portion through a fastening means so that the first part is as closely attached to the first ring portion as possible, and the plurality of steel wires are inserted between the first part and the first ring portion; A step of cutting off the ends exposed to the outside of the plurality of steel wires sandwiched between the first part and the first ring portion; and A step of injecting and hardening a liquid compound to improve the bonding strength of a plurality of steel wires of the submarine cable into an injection hole connected to the second through hole of the base portion; A method for securing a submarine cable to a field recovery connection box, comprising:

17. In paragraph 16, A method for securing a submarine cable to a field recovery joint, further comprising: a step of placing a cover plate to block a gap between the first through hole of the first part and the submarine cable, and between the other end of the second part and the submarine cable.

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