A bend limiter which can be disassembled at any node and a method for installing the same

Abstract

This invention provides a bend limiter that can be disassembled and installed at any node, and its installation method, belonging to the field of marine engineering and underwater cable protection. The bend limiter includes several bend limiting units; each bend limiting unit includes a first bend limiting unit and a second bend limiting unit; the first bend limiting unit includes a pair of radially openable and closable first semi-ring shells for covering the outer wall of the submarine cable, and the outer wall end of the first semi-ring shell is formed with a first coupling interface; the second bend limiting unit includes a pair of second semi-ring shells, and the inner wall of the second semi-ring shell is provided with a second coupling interface adapted to the first coupling interface; through the connection of the first coupling interface and the second coupling interface, the first bend limiting unit and the second bend limiting unit are arranged alternately along the axial direction of the submarine cable. This invention allows for independent disassembly and replacement of the bend limiter at any axial position of the submarine cable, without the need for sleeve connection from the end of the submarine cable, making installation and maintenance convenient and efficient; the connection between the units is stable, improving the overall mechanical strength and fatigue resistance.

Description

Technical Field

[0001] This invention relates to the field of marine engineering and underwater cable protection technology, and in particular to a bend limiter that can be installed and removed at any node and its installation method. Background Technology

[0002] In offshore wind power, deep-sea oil and gas projects, submarine cables and flexible conduits are prone to fatigue damage or even breakage during laying, operation, and retrieval due to excessive bending, torsion, and dynamic loads from ocean currents. To control the minimum bending radius of the conduits and ensure service safety, bending limiters are usually installed at key locations such as joints and bending transition sections.

[0003] Currently, most mainstream bending limiters adopt an integral structure or a chain-type series nested structure. The individual units interlock with each other and are axially nested and interlocked. They need to be installed sequentially from the end of the cable and spliced ​​section by section to form a continuous protection section. Therefore, this kind of traditional structure has obvious defects in practical applications: (1) Traditional limiters must be installed sequentially from the end of the cable. For existing submarine cables that have been laid and deployed, it is not possible to directly add or replace protection devices at any node in the middle, which is difficult to meet the needs of later operation and maintenance, local reinforcement and other scenarios; (2) When a section is damaged or aged, or when maintenance or jointing operations need to be carried out in the middle of the cable, the limiters on one side or the entire section at the target location must be removed sequentially, and it is not possible to achieve independent disassembly and replacement of individual units. In deep sea, offshore and harsh sea conditions, this method of operation is time-consuming, risky and significantly increases operation and maintenance costs; (3) The chain-type series structure is similar to a "zipper". When under force, the stress is easily concentrated at the unit connection part, and the overall strength is limited by the weakest node. Under the long-term action of dynamic loads such as waves and ocean currents, it is easy to cause sequential disintegration and zipper failure starting from the end. Once a local damage occurs, the entire protection will fail, posing a serious threat to the safety of the pipeline. (4) Traditional interlocking structures have a single load transmission path during bending, which is prone to local stress concentration. Long-term service can easily lead to fatigue cracking and loosening of connections, making it difficult to meet the long-term, high-reliability protection requirements of deep sea.

[0004] In summary, existing bend limiters struggle to simultaneously meet requirements such as reliable bend limiting, arbitrary node assembly / disassembly, independent local maintenance, and high structural stability. Therefore, there is an urgent need to develop a new type of polyurethane bend limiter that can be directly assembled / disassembled at any location on the submarine cable, features independent locking of individual units, non-nested connections between units, high overall strength, and easy local maintenance, in order to address the inherent shortcomings of traditional products in terms of installation, maintenance, and reliability. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to overcome the problems of existing bending limiters that require connection from the end of the submarine cable, cannot be disassembled at any node, and have insufficient reliability of connection between individual units, and to provide a bending limiter and its installation method that can be disassembled at any node.

[0006] To achieve the above objectives, the present invention provides a bend limiter that can be disassembled and assembled at any node, comprising several bend limiting units;

[0007] The bending limiting unit includes a first bending limiting unit and a second bending limiting unit;

[0008] The first bending limiting unit includes a pair of radially openable and closable first semi-ring shells for covering the outer wall of the submarine cable, and the outer wall end of the first semi-ring shell is formed with a first coupling interface.

[0009] The second bending limiting unit includes a pair of radially openable and closed second semi-ring shells for covering the outer wall of the submarine cable, and the inner wall of the second semi-ring shell is provided with a second coupling interface adapted to the first coupling interface;

[0010] The first and second coupling interfaces are connected to allow the first and second bending limiters to be alternately connected and arranged along the axial direction of the coastal cable.

[0011] In one embodiment of the invention, a radial locking mechanism is further included, which is used to close and lock a pair of first semi-ring housings and a pair of second semi-ring housings respectively.

[0012] In one embodiment of the present invention, the first coupling interface is a boss and the second coupling interface is a groove, and the boss and the groove are inserted into each other.

[0013] In one embodiment of the present invention, the boss and the groove are annular, T-shaped or Ω-shaped.

[0014] In one embodiment of the present invention, the radial locking mechanism includes a radial locking bolt, which is used to close and lock a pair of first semi-ring housings and a pair of second semi-ring housings respectively.

[0015] In one embodiment of the present invention, a pair of first semi-ring housings are provided with first radial locking bolt holes that are aligned with each other, and a pair of second semi-ring housings are provided with second radial locking bolt holes that are aligned with each other, wherein the first radial locking bolt holes and the second radial locking bolt holes are for the radial locking bolts to pass through.

[0016] In one embodiment of the present invention, the radial locking mechanism is a quick-release buckle or a hydraulic locking device.

[0017] In one embodiment of the present invention, a metal skeleton or reinforcing fiber layer is pre-embedded inside the first semi-ring shell and / or the second semi-ring shell.

[0018] In one embodiment of the present invention, the first bending limiting monomer and the second bending limiting monomer are made of urethane material.

[0019] Based on the same inventive concept, the present invention also provides an installation method for a bend limiter that can be installed and removed at any node as described above, the method comprising:

[0020] S1. The pair of first semi-ring shells of the first bending limiting unit are radially opened and wrapped around the submarine cable at a preset position, and locked by a radial locking mechanism, so that the first bending limiting unit is independently fixed to the outer wall of the submarine cable.

[0021] S2. The pair of second semi-ring shells of the second bending limiting unit are radially opened and wrapped around the submarine cable position adjacent to the first bending limiting unit.

[0022] S3. Align the second coupling interface of the second bending limiting unit with the first coupling interface of the first bending limiting unit and insert it axially, so that the first bending limiting unit and the second bending limiting unit are alternately connected and arranged along the axial direction of the coastal cable.

[0023] S4. Lock a pair of second semi-ring shells through a radial locking mechanism to independently fix the second bending limiting unit to the outer wall of the submarine cable;

[0024] S5. Axial fastening bolts are sequentially inserted into the axial fastening channels of the first bending limiting unit and the second bending limiting unit and locked to achieve axial rigid connection between adjacent units.

[0025] S6. Repeat steps S2-S5 to complete the continuous installation of several bending limit units.

[0026] As can be seen from the above, the present invention has at least the following beneficial effects:

[0027] The present invention provides a bend limiter and its installation method that can be disassembled and installed at any node. It enables independent disassembly and replacement of the bend limiter at any axial position of the submarine cable without the need for connection from the end of the submarine cable, making installation and maintenance convenient and efficient. Through the interlocking structure design of the coupling interface, the connection between individual units is stable, improving the overall mechanical strength and fatigue resistance. Each bend limiter unit can be fixed independently, and disassembly and installation do not interfere with each other, adapting to complex sea conditions and effectively ensuring the safety of submarine cable use, significantly enhancing practicality and reliability. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in this invention or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structure of the present invention.

[0030] Figure 2 for Figure 1 A magnified view of part A in the middle.

[0031] Figure 3 for Figure 1 The main view.

[0032] Figure 4 for Figure 3 A cross-sectional view of BB.

[0033] Figure 5 for Figure 4 A magnified view of part C in the middle.

[0034] Figure 6 This is a schematic diagram of the structure of the first semi-ring shell of the present invention.

[0035] Figure 7 This is a schematic diagram of the structure of the second semi-ring shell of the present invention.

[0036] The reference numerals in the attached figures are explained as follows:

[0037] 1. Bending limiting unit; 11. First bending limiting unit; 111. First semi-ring shell; 112. First coupling interface; 12. Second bending limiting unit; 121. Second semi-ring shell; 122. Second coupling interface. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0039] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this invention should have the ordinary meaning understood by those skilled in the art. The terms "first," "second," and similar terms used in the embodiments of this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0040] To keep the following description of the embodiments of the present invention clear and concise, detailed descriptions of some known functions and components have been omitted.

[0041] like Figures 1 to 7 A bend limiter, detachable at any node, is shown in one embodiment. It includes several bend-limiting units 1. Each bend-limiting unit 1 includes a first bend-limiting single unit 11 and a second bend-limiting single unit 12. The first bend-limiting single unit 11 includes a pair of radially openable and closable first semi-annular shells 111 for covering the outer wall of a submarine cable. The outer wall end of the first semi-annular shell 111 is formed with a first coupling interface 112. The second bend-limiting single unit 12 includes a pair of radially openable and closable second semi-annular shells 121 for covering the outer wall of a submarine cable. The inner wall of the second semi-annular shell 121 is provided with a second coupling interface 122 adapted to the first coupling interface 112. The first bend-limiting single unit 11 and the second bend-limiting single unit 12 are arranged alternately along the axial direction of the submarine cable through the connection of the first coupling interface 112 and the second coupling interface 122.

[0042] This invention enables independent disassembly and replacement of the bend limiter at any axial position of the submarine cable without the need for connection from the end of the cable, making installation and maintenance convenient and efficient. Through the interlocking structure design of the coupling interface, the connection between individual units is stable, improving the overall mechanical strength and fatigue resistance. Each bend limiter unit can be fixed independently, and disassembly and assembly do not interfere with each other, adapting to complex sea conditions and effectively ensuring the safety of submarine cable use, significantly enhancing practicality and reliability.

[0043] In a preferred embodiment of the present invention, a metal skeleton or a reinforcing fiber layer is pre-embedded inside the first semi-ring shell 111 and / or the second semi-ring shell 121. The pre-embedded metal skeleton can significantly improve the structural strength and rigidity of the shell, while the reinforcing fiber layer can effectively improve the fatigue resistance, impact resistance and corrosion resistance of the shell. Both can further optimize the load-bearing capacity of the shell, extend the service life of the overall device, and adapt to the use requirements under heavy load and complex working conditions.

[0044] In a preferred embodiment of the present invention, the first bending limiting monomer 11 and the second bending limiting monomer 12 are made of urethane material. Urethane material has excellent elasticity, wear resistance and anti-aging properties, which can meet the flexible limiting requirements of the bending limiting monomer, while having good load-bearing capacity. It can achieve effective bending limiting while avoiding rigid damage to the overall structure, thus taking into account both bending limiting effect and structural protection performance.

[0045] In a preferred embodiment of the present invention, the first coupling interface 112 is a boss, and the second coupling interface 122 is a groove adapted to the boss. During assembly, the boss of the first semi-annular housing 111 is inserted into the groove of the second semi-annular housing 121, realizing the rapid positioning and insertion of the first coupling interface 112 and the second coupling interface 122. The outer contour of the boss matches the inner contour of the groove, and the two are in clearance fit or interference fit, which can effectively limit the radial offset and circumferential rotation between components, ensuring the coaxiality and connection stability of the structure after docking. At the same time, this plug-in coupling structure is simple in form, easy to process, and convenient to disassemble and assemble, which can improve the overall assembly efficiency and is suitable for rapid docking and installation of components in various scenarios.

[0046] Furthermore, the boss and groove can be configured as an annular structure, i.e., the first coupling interface 112 is an annular boss, and the second coupling interface 122 is an annular groove that matches the contour of the annular boss. During assembly, the annular boss is coaxially inserted into the annular groove to achieve full circumferential positioning, effectively preventing radial offset, circumferential deflection, and wobbling after component docking, and significantly improving the coaxial accuracy and overall stability of the coupling connection; the complementary concave and convex interfaces can effectively transfer and disperse multi-directional loads (bending, tension, torsion), which can significantly avoid stress concentration at the component docking point, improve the load-bearing capacity and fatigue resistance of the overall structure, and extend the service life of the device; moreover, the annular structure is easy to process and form, facilitating mass production and assembly.

[0047] Optionally, the boss and groove can also adopt a T-shaped or Ω-shaped structure, that is, the first coupling interface 112 is a T-shaped boss or an Ω-shaped boss, and the second coupling interface 122 is correspondingly set as a T-shaped groove or an Ω-shaped groove that matches the contour of the boss. During assembly, the T-shaped or Ω-shaped boss and the corresponding groove are inserted and engaged. The irregular cross-section can achieve multiple functions of axial limiting, radial constraint and anti-disengagement limiting, which can effectively prevent the parts from loosening or shifting after insertion. At the same time, the structure has stronger engagement stability and excellent anti-torsion and anti-pull-out performance. It is suitable for application scenarios with high requirements for connection reliability, such as vibration conditions and heavy-load connections. Different cross-sectional coupling structures can be flexibly selected according to the actual assembly space and stress requirements.

[0048] Of course, in addition to annular, T-shaped, and Ω-shaped structures, the above-mentioned bosses and grooves can also adopt other suitable irregular cross-sectional forms such as rectangular, dovetail, and polygonal shapes. Conventional modifications, substitutions, and improvements made by those skilled in the art to the shape, size, and mating method of the coupling interface without departing from the core concept of this invention all fall within the protection scope of this invention.

[0049] The bending limiter provided in this embodiment of the invention, which can be disassembled and assembled at any node, also includes a radial locking mechanism. This radial locking mechanism is used to close and lock a pair of first semi-ring housings 111 and a pair of second semi-ring housings 121 respectively. Preferably, the radial locking mechanism may include radial locking bolts. Specifically, the pair of first semi-ring housings 111 have mutually aligned first radial locking bolt holes, and the pair of second semi-ring housings 121 have mutually aligned second radial locking bolt holes. The first and second radial locking bolt holes are for the radial locking bolts to pass through. By the radial locking bolts passing through the corresponding bolt holes and locking, reliable closure of the pair of first semi-ring housings 111 and the pair of second semi-ring housings 121 can be achieved, preventing gaps, loosening, or misalignment at the housing joint. Combined with the insertion fit of the annular boss and the annular groove, a dual locking mechanism of "mortise and tenon + bolt" is achieved, further enhancing the connection reliability and sealing performance of the overall structure, adapting to the usage requirements under various working conditions.

[0050] Optionally, the radial locking mechanism can also employ a quick-release buckle or a hydraulic locking device. A quick-release buckle enables rapid assembly and disassembly of the semi-annular housing and convenient locking, effectively improving assembly and maintenance efficiency. A hydraulic locking device can output a uniform and high-tonnage radial locking force, suitable for harsh working conditions such as heavy loads, high pressure, and vibration. Of course, in addition to the aforementioned radial locking bolts, quick-release buckles, and hydraulic locking devices, those skilled in the art can, according to actual working conditions, employ other conventional locking structures such as clamp-type locking components, eccentric locks, and pneumatic locking components. Equivalent substitutions, simple modifications, and improvements made to the type and structure of the radial locking mechanism without departing from the core locking concept of this invention all fall within the protection scope of this invention.

[0051] This invention utilizes polyurethane material, which possesses excellent resistance to seawater corrosion, wear, fatigue, and impact. Combined with the reinforced structure of this invention, it effectively enhances the protection of submarine cables and extends their service life. Furthermore, the modular design allows for the replacement of only the damaged individual component when the cable's protective structure is partially damaged, eliminating the need for complete replacement. This significantly reduces the difficulty of subsequent maintenance, effectively lowers maintenance costs throughout the cable's lifespan, and improves the stability and economy of submarine cable operation.

[0052] Corresponding to the above-described embodiment of a bend limiter that can be installed and removed at any node, another embodiment of the present invention also provides an installation method for a bend limiter that can be installed and removed at any node, the method comprising:

[0053] S1. The pair of first semi-ring shells 111 of the first bending limiting unit 11 are radially opened and wrapped around the submarine cable at a preset position, and locked by the radial locking mechanism, so that the first bending limiting unit 11 is independently fixed to the outer wall of the submarine cable.

[0054] S2. The pair of second semi-annular shells 121 of the second bending limiting unit 12 are radially opened and wrapped around the submarine cable position adjacent to the first bending limiting unit 11.

[0055] S3. Align the second coupling interface 122 of the second bending limiting unit 12 with the first coupling interface 112 of the first bending limiting unit 11 and insert it axially, so that the first bending limiting unit 11 and the second bending limiting unit 12 are alternately connected and arranged along the axial direction of the coastal cable.

[0056] S4. Lock a pair of second semi-ring shells 121 by radial locking mechanism, so that the second bending limiting unit 12 is independently fixed to the outer wall of the submarine cable;

[0057] S5. Axial fastening bolts are sequentially inserted into the axial fastening channels of the first bending limiting unit 11 and the second bending limiting unit 12 and locked to achieve axial rigid connection between adjacent units.

[0058] S6. Repeat steps S2-S5 to complete the continuous installation of several bending limit units 1.

[0059] The following detailed description, in conjunction with specific operational steps, illustrates the installation method of the bending limiter of this invention, which can be installed and removed at any node, ensuring that the operation is repeatable and feasible:

[0060] 1. Installation point selection: First, determine the starting position where protection needs to be activated on the submarine cable to be protected, and mark this position as the installation reference for the first section of the bend limiting unit 1, ensuring that the installation position corresponds completely to the area of ​​the submarine cable to be protected.

[0061] 2. Installation of the first bending limiting unit 11: Select a first bending limiting unit 11, open its pair of first semi-ring shells 111 along the split surface, and then align the pair of first semi-ring shells 111 to cover the marked selected position on the submarine cable; adjust the position of the first bending limiting unit 11 so that the inner hole of the first semi-ring shell 111 fits tightly with the outer surface of the submarine cable without any loose gaps, then pass the radial locking bolt through the first radial locking bolt hole on the first semi-ring shell 111 and tighten the radial locking bolt to make the first bending limiting unit 11 independently and firmly fixed to the submarine cable, thus completing the installation of the first bending limiting unit 11.

[0062] 3. Connection of the second bending limiting unit 12: Select a second bending limiting unit 12 and, in the same manner as the first bending limiting unit 11, open its pair of second semi-ring shells 121 and wrap them around the submarine cable position adjacent to the first bending limiting unit 11, so that the ends of the second bending limiting unit 12 and the first bending limiting unit 11 are tightly connected; first, align the groove on the second semi-ring shell 121 with the boss at the end of the first semi-ring shell 111, and slowly insert it so that the boss is embedded in the groove, to prevent the unit from sliding axially or rotating circumferentially along the submarine cable.

[0063] 4. Locking and fixing the second bending limiting unit 12: Close and align the pair of second semi-ring shells 121 of the second bending limiting unit 12, and tighten its own radial locking bolts to fix the second bending limiting unit 12 independently on the submarine cable, ensuring that the second bending limiting unit 12 is tightly attached to the submarine cable, while maintaining a stable connection with the adjacent first bending limiting unit 11.

[0064] 5. Axial fastening of the first limiting unit: Take an axial fastening bolt of suitable length and pass it through the aligned axial fastening channels on the first bending limiting unit 11 and the second bending limiting unit 12 in sequence, ensuring that the bolt passes through smoothly without jamming. Put a nut on the end of the bolt and tighten it evenly to firmly pull the adjacent first bending limiting unit 11 and second bending limiting unit 12 axially, forming a rigid integral connection and improving the overall stability of the protection structure.

[0065] 6. Protection Section Extension: Repeat steps 2-5 above in the alternating sequence of “first bend limiting unit 11 → second bend limiting unit 12 → first bend limiting unit 11 → second bend limiting unit 12…” to gradually extend the protection section until the area to be protected by the submarine cable is completely covered, achieving the required protection length. In this embodiment, the installation direction can be extended in both directions without limiting a fixed installation starting point, adapting to the installation needs of different scenarios.

[0066] 7. Disassembly of a Bending Limiter Unit: When a bending limiter unit is damaged and needs replacement or maintenance, disassembly is performed at the target bending limiter unit location. The specific steps are as follows: First, loosen the axial fastening bolts on the target bending limiter unit and its adjacent bending limiter units to release the axial tension between the adjacent bending limiter units; then, loosen the radial locking bolts on the target bending limiter unit itself to open the pair of semi-ring shells of the target bending limiter unit; finally, detach the coupling interface (axial boss and groove) between the target bending limiter unit and the adjacent bending limiter units, and the target bending limiter unit can be removed from the submarine cable. The entire disassembly process does not require touching other bending limiter units upstream or downstream, and does not affect the fixed state of other bending limiter units on the submarine cable, achieving rapid maintenance and replacement.

[0067] The embodiments of this invention are intended to cover all such substitutions, modifications, and variations falling within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this invention should be included within the protection scope of this invention.

Claims

1. A bend limiter that can be installed and removed at any node, characterized in that, Includes several bending limit units; The bending limiting unit includes a first bending limiting unit and a second bending limiting unit; The first bending limiting unit includes a pair of radially openable and closable first semi-ring shells for covering the outer wall of the submarine cable, and the outer wall end of the first semi-ring shell is formed with a first coupling interface. The second bending limiting unit includes a pair of radially openable and closed second semi-ring shells for covering the outer wall of the submarine cable, and the inner wall of the second semi-ring shell is provided with a second coupling interface adapted to the first coupling interface; The first and second coupling interfaces are connected to allow the first and second bending limiters to be alternately connected and arranged along the axial direction of the coastal cable.

2. A bend limiter that can be installed and removed at any node according to claim 1, characterized in that: It also includes a radial locking mechanism, which is used to close and lock a pair of first semi-ring housings and a pair of second semi-ring housings respectively.

3. A bend limiter that can be disassembled and assembled at any node according to claim 1 or 2, characterized in that: The first coupling interface is a boss, and the second coupling interface is a groove, with the boss and the groove being inserted into each other.

4. A bend limiter that can be installed and removed at any node according to claim 3, characterized in that: The protrusions and grooves are annular, T-shaped, or Ω-shaped.

5. A bend limiter that can be disassembled and assembled at any node according to claim 2, characterized in that: The radial locking mechanism includes radial locking bolts, which are used to close and lock a pair of first semi-ring housings and a pair of second semi-ring housings respectively.

6. A bend limiter that can be installed and removed at any node according to claim 5, characterized in that: A pair of first semi-ring housings are provided with first radial locking bolt holes that are aligned with each other, and a pair of second semi-ring housings are provided with second radial locking bolt holes that are aligned with each other. The first and second radial locking bolt holes are for the radial locking bolts to pass through.

7. A bending limiter that can be disassembled and assembled at any node according to claim 2, characterized in that: The radial locking mechanism is a quick-release buckle or a hydraulic locking device.

8. A bend limiter that can be disassembled and assembled at any node according to claim 1 or 2, characterized in that: The first semi-ring shell and / or the second semi-ring shell have a metal skeleton or reinforcing fiber layer embedded inside.

9. A bend limiter that can be disassembled and assembled at any node according to claim 1 or 2, characterized in that: The first and second bending-limiting monomers are made of urethane material.

10. A method for installing a bend limiter that can be disassembled and installed at any node as described in any one of claims 1-9, characterized in that: The method includes: S1. The pair of first semi-ring shells of the first bending limiting unit are radially opened and wrapped around the submarine cable at a preset position, and locked by a radial locking mechanism, so that the first bending limiting unit is independently fixed to the outer wall of the submarine cable. S2. The pair of second semi-ring shells of the second bending limiting unit are radially opened and wrapped around the submarine cable position adjacent to the first bending limiting unit. S3. Align the second coupling interface of the second bending limiting unit with the first coupling interface of the first bending limiting unit and insert it axially, so that the first bending limiting unit and the second bending limiting unit are alternately connected and arranged along the axial direction of the coastal cable. S4. Lock a pair of second semi-ring shells through a radial locking mechanism to independently fix the second bending limiting unit to the outer wall of the submarine cable; S5. Axial fastening bolts are sequentially inserted into the axial fastening channels of the first bending limiting unit and the second bending limiting unit and locked to achieve axial rigid connection between adjacent units. S6. Repeat steps S2-S5 to complete the continuous installation of several bending limit units.

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