Subsea pipeline bottom clearance towing anti-sink buffer device

Abstract

The application discloses a seabed pipeline off-bottom towing anti-sinking buffer device, and belongs to the field of ocean engineering. The buffer device comprises a pipeline and a connecting cable arranged above the pipeline. A plurality of buffer leg assemblies are arranged at equal intervals along the length direction of the bottom of the pipeline. The buffer leg assembly comprises a connecting piece fixedly sleeved on the outside of the pipeline, fixed sleeves symmetrically fixedly connected on both sides of the bottom of the connecting piece, a movable rod slidingly inserted into the bottom of the fixed sleeve, a buffer spring fixedly arranged in the fixed sleeve and fixedly connected with the top of the movable rod, and a supporting leg fixedly connected with the bottom of the movable rod. Through the design of the buffer leg assembly, effective buffer support can be provided between the bottom of the pipeline and the seabed, so that the pipeline is prevented from being directly impacted against the seabed due to jolting during towing, damage of the pipeline is avoided, the risk of sinking of the pipeline into the seabed is reduced, the safety and stability of towing are improved, and the towing requirement under different seabed terrain conditions is met.

Description

Technical Field

[0001] This application relates to the field of marine engineering technology, specifically a buffer device for preventing sinking during off-bottom towing of subsea pipelines. Background Technology

[0002] In the field of marine engineering, subsea pipelines are key facilities for marine oil and gas transportation and seawater discharge projects, and the reliability and economy of their laying technology directly affect the overall benefits of the project. Currently, the mature subsea pipeline laying technologies in the industry mainly include pipelaying vessel method, hoisting method, and towing method. Due to their different technical characteristics, these methods also have significant differences in applicable scenarios and limitations.

[0003] While pipelaying vessels, as a traditional method, enable continuous operation, their high equipment costs and strict limitations on pipe diameter restrict their application in large-diameter subsea pipelines, limiting their suitability for near-shore large-scale projects. Lifting methods rely on barge transport and crane vessel lifting, but they involve shorter pipeline lengths per operation, resulting in lower efficiency. Furthermore, each pipeline segment requires underwater connection, often necessitating dozens of work windows to complete the entire project, creating significant time pressure. More importantly, this method has poor resistance to wind and waves; sudden gusts or high waves cannot halt the lifting process immediately, posing a high safety risk.

[0004] Pipe towing is a preferred method for laying large-diameter, thin-walled subsea pipelines in nearshore areas, especially, because it does not rely on specialized pipelaying vessels and can be completed using only ordinary tugboats. It is also adaptable to various water depths. Bottom towing involves pulling prefabricated pipe sections from the land into the water via a slipway and then directly towing them along the seabed. Due to the pipeline's proximity to the seabed, it is adaptable to environmental factors such as wind, waves, and currents, and can be interrupted if necessary, resulting in less time and economic loss. Therefore, it is widely used in near-shore, beach, and riverbed pipeline laying. However, this method has limitations. During towing, the pipeline must pass through seabeds with varying geological conditions, and changes in seabed resistance and slope significantly affect towing stability, increasing construction difficulty. Floating towing involves attaching buoys or airbags to the pipe sections to make them float on the sea surface, with a main tugboat, auxiliary vessels, and guard vessels working together to tow them. However, it is greatly affected by wind, waves, and currents, has strict requirements for the operational window, and its construction efficiency is easily constrained by the natural environment.

[0005] To address the technical shortcomings of bottom towing and floating towing methods, improved technologies have emerged that fall between the two. For example, the Chinese utility model patent CN222760409U discloses an underwater towing device for subsea pipelines. This device uses buoys and counterweights (anchor chains) to suspend the pipeline in the water, enabling towing off the bottom. This technology avoids direct contact between the pipeline and the seabed, reducing seabed resistance and towing force requirements, while also minimizing the impact of surface wind, waves, and currents. Simultaneously, the friction generated by the anchor chain in contact with the seabed maintains the pipeline's towing stability, and the tension applied by the stern tugboat prevents pipeline deviation or deformation. The device is simple in structure and easy to use. However, this device relies solely on the buoys and anchor chains for pipeline levitation, lacking an effective anti-sinking buffer design. The bottom of the pipeline is in soft contact with the seabed via the anchor chain; therefore, during severe turbulence, the pipeline may still sink due to excessive swaying, posing a safety hazard and failing to meet the requirements for high-stability laying.

[0006] Therefore, this application provides a buffer device for preventing sinking of subsea pipelines during off-bottom towing, in order to solve the above-mentioned problems. Utility Model Content

[0007] This application provides a subsea pipeline towing anti-sinking buffer device, which aims to solve the problems mentioned in the background art, such as the existing subsea pipeline underwater towing devices only use buoys and anchor chains to suspend the pipeline, lacking an effective anti-sinking buffer design, and the possibility of the pipeline sinking to the seabed when the turbulence is too large.

[0008] To achieve the above objectives, this application provides the following technical solution: a subsea pipeline anti-sinking buffer device for off-bottom towing, comprising a pipeline and a connecting cable disposed above the pipeline. A plurality of straps connected to the connecting cable are evenly spaced along the length of the pipeline. An anchor chain for pulling down the pipeline is connected to the bottom of each strap. A buoy for pulling up the pipeline is disposed above the connecting cable. A plurality of buffer leg assemblies are evenly spaced along the length of the bottom of the pipeline. Each buffer leg assembly includes a connector fixedly sleeved outside the pipeline, fixed sleeves symmetrically fixedly connected to both sides of the bottom of the connector, a movable rod slidably inserted into the bottom of the fixed sleeve, a buffer spring fixedly disposed inside the fixed sleeve and fixedly connected to the top of the movable rod, and a support foot fixedly connected to the bottom of the movable rod. The buffer outrigger assembly is fixed to the pipeline via connectors. When the pipeline encounters protrusions or depressions in the seabed during towing, the outriggers first contact the seabed, the movable rod slides in the fixed sleeve, and the buffer spring extends and retracts accordingly. The elastic deformation of the spring absorbs and buffers the impact force, thereby achieving buffer support between the pipeline and the seabed.

[0009] Preferably, to enable the support foot to adapt to the seabed, the support foot consists of a ball seat and a sphere rotatably embedded in the top of the ball seat, with the sphere fixedly connected to the bottom of the movable rod. This allows the support foot to flexibly adapt to various seabed topography, including protrusions, depressions, and inclinations, ensuring support stability and preventing displacement or damage to the pipeline due to uneven stress caused by uneven terrain, further improving the applicability of the device in complex seabed environments.

[0010] Preferably, to increase the contact area between the ball seat and the seabed, a sled is fixedly connected to the bottom of the ball seat. This increases the contact area between the ball seat and the seabed, reduces the pressure of the support foot on the seabed, minimizes damage to the seabed, and improves the stability of the support foot on the seabed, preventing the support foot from sinking into softer seabed and ensuring the stability of the pipeline during towing.

[0011] Preferably, to improve the buffering effect: a hydraulic damper is inserted into the inner ring of the buffer spring, the top of the hydraulic damper is fixedly connected to the top wall inside the fixed sleeve, and the output end of the hydraulic damper is fixedly connected to the top of the movable rod. The cooperation between the hydraulic damper and the buffer spring improves the buffering effect, effectively suppresses the vibration of the buffer spring, prevents continuous oscillation of the pipeline after impact, reduces the amplitude of pipeline turbulence, and further ensures the safety and stability of pipeline towing.

[0012] Preferably, to improve the sealing performance between the movable rod and the fixed sleeve, a sealing ring is provided on the movable rod to seal the gap between the movable rod and the fixed sleeve. This sealing ring is the same type used for hydraulic cylinder piston rods, effectively improving the sealing performance between the movable rod and the fixed sleeve, preventing seawater and impurities in the seawater from entering the fixed sleeve, avoiding corrosion or blockage of the buffer spring and hydraulic damper, ensuring their normal operation, and extending the service life of the device.

[0013] Preferably, the connector includes a lower retaining ring and an upper retaining ring connected to the lower retaining ring by bolts, with two fixing sleeves fixedly connected to both sides of the bottom of the lower retaining ring. This facilitates the installation and fixing of the buffer leg assembly onto the pipeline, ensuring a firm and reliable connection. It also facilitates disassembly and maintenance, adapts to pipelines of different diameters, and improves the versatility and practicality of the device.

[0014] Preferably, to prevent wear on the pipe caused by the connector: both the lower and upper retaining rings are fixedly fitted with gaskets on their inner sides for contact with the pipe. These gaskets are made of neoprene rubber or polyurethane toothed pads. This prevents direct contact between the lower and upper retaining rings and the pipe, protecting the outer surface of the pipe. It also increases the friction between the connector and the pipe, preventing the connector from sliding on the pipe and ensuring connection stability. The neoprene rubber or polyurethane toothed pads also provide a certain degree of cushioning.

[0015] Preferably, at least one buoy is connected to a buoy that floats on the water surface. The buoy serves as a clear marker, providing clear location information for offshore workers and facilitating rapid positioning of the pipeline in complex marine environments. This is especially beneficial at night or in low visibility conditions, effectively preventing collisions with the pipeline by other vessels and ensuring operational safety and pipeline integrity.

[0016] Preferably, it also includes a lead tugboat, which is connected to one end of the pipeline via a towing cable. The lead tugboat provides the main traction force to the pipeline, propelling it to move in a predetermined direction in the seawater.

[0017] Preferably, the system also includes a stern tugboat, which is connected to the other end of the pipeline via a towing cable. When the pipeline is subjected to strong lateral currents, appropriate tension can be applied to prevent the pipeline from shifting or deforming excessively, ensuring the stability and straightness of the pipeline during towing, improving installation accuracy, and ensuring the quality of the entire subsea pipeline laying project.

[0018] This application, through the design of the buffer outrigger assembly, can provide effective buffer support between the bottom of the pipeline and the seabed, avoiding damage to the pipeline caused by direct impact with the seabed due to turbulence during towing, while reducing the risk of the pipeline sinking to the seabed, improving the safety and stability of towing, and adapting to the towing needs under different seabed terrain conditions.

[0019] The support foot of this application consists of a ball seat and a ball rotatably embedded on the top of the ball seat, which allows the support foot to flexibly adapt to various terrains of the seabed, including protrusions, depressions and inclinations, to ensure the stability of the support and avoid displacement or damage to the pipeline due to uneven stress caused by uneven terrain, thereby further improving the applicability of the device in complex seabed environments. Attached Figure Description

[0020] Figure 1 A schematic diagram of a subsea pipeline anti-sinking buffer device for off-bottom towing;

[0021] Figure 2 A schematic diagram showing the connection between the buffer support leg assembly and the pipeline;

[0022] Figure 3 This is a schematic diagram of the internal structure of the fixed sleeve.

[0023] In the picture:

[0024] 1. Pipeline; 2. Connecting cable; 3. Straps; 4. Anchor chain; 5. Buoy; 6. Buffer leg assembly; 61. Connector; 611. Lower shackle; 612. Upper shackle; 613. Pad; 62. Fixed sleeve; 63. Movable rod; 631. Sealing ring; 64. Buffer spring; 65. Support foot; 651. Ball seat; 652. Ball; 66. Sled; 67. Hydraulic damper; 7. Buoy; 8. Head tugboat; 9. Towing cable; 10. Tail tugboat. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0026] Example 1

[0027] This embodiment provides a buffer device for preventing sinking during off-bottom towing of subsea pipelines, such as... Figure 1-3 As shown, the buffer device includes a pipe 1 and a connecting cable 2 positioned above the pipe 1. Several straps 3, evenly spaced along the length of the pipe 1 and connected to the connecting cable 2, are attached to the pipe 1. Anchor chains 4, used to pull down the pipe 1, are connected to the bottom of the straps 3. A float 5, used to pull up the pipe 1, is positioned above the connecting cable 2. The connecting cable 2, connected to the straps 3 evenly spaced along the length of the pipe 1, forms a stable connection system that evenly distributes the external forces acting on the pipe 1 during towing, ensuring the overall stability of the pipe 1 in a suspended state. Simultaneously, the evenly spaced arrangement optimizes the force distribution, preventing excessive localized stress that could lead to deformation or damage to the pipe 1. The connecting cable 2 acts as a "bridge," transmitting the upward pulling force of the float 5 and the downward pulling force of the strap 3-counterweight 4 system to the pipe 1, maintaining its suspended state. By suspending the pipe 1 in the water using floats 5 and counterweights 4, the pipe 1 can be towed off the bottom. Off-bottom towing is between floating towing and bottom towing methods; it does not directly contact the seabed and is not affected by the seabed, thus requiring less towing force. It also avoids the effects of surface waves and currents on the pipe 1, as is seen in floating towing. This device has a simple structure, is easy to use, and performs well. The straps 3 are made of high-strength polyester webbing or galvanized steel straps.

[0028] The buoyancy of the float 5 is adjustable, and at least one valve is installed on the float 5. Specifically, a DN1000 steel pipe sealed on both sides is used as the float 5. The length of a single steel pipe is 5m, and the buoyancy is approximately 4t. The steel pipe is directly tied to the connecting cable 2 using slings. Two valves are installed at the top of the steel pipe. The valves are used to fill the float 5 with water after the pipe 1 is connected, to retrieve the float 5, and to control the amount of water filled into the float 5 to control its buoyancy. The buoyancy of the float 5 is adjustable, and the amount of water filled is controlled by at least one valve at the top, thereby precisely adjusting the buoyancy of the float 5. This feature allows the device to flexibly change the buoyancy of the float 5 according to factors such as the actual weight of the pipe 1, ocean currents, and seawater density, ensuring that the pipe 1 is always in a stable suspended state, improving the adaptability of the device to different operating environments. After the pipe 1 is connected, water can be filled into the float 5 through the valves to reduce its buoyancy, making it easier to retrieve the float 5, reducing device costs, and improving resource utilization. When buoyancy of pontoon 5 needs to be increased, the valve is closed, filling the pontoon 5 with air. The density difference between air and seawater generates upward buoyancy. When buoyancy needs to be decreased, the valve is opened, allowing seawater to enter the pontoon 5. As the amount of water increases, the overall weight of the pontoon 5 increases, and the buoyancy decreases accordingly. After the pipeline 1 is connected, the valve is opened, allowing a large amount of seawater to flood into the pontoon 5. When the buoyancy is less than the weight of the pontoon 5 itself, it sinks, facilitating recovery. In this way, the buoyancy of pontoon 5 can be adjusted precisely and at any time according to actual operational needs, ensuring the suspension stability of pipeline 1 and the smooth progress of subsequent operations.

[0029] Multiple buffer support leg assemblies 6 are evenly spaced along the length of the bottom of the pipeline 1. Each buffer support leg assembly 6 includes a connector 61 fixedly sleeved on the outside of the pipeline 1, a fixed sleeve 62 symmetrically fixed on both sides of the bottom of the connector 61, a movable rod 63 slidably inserted into the bottom of the fixed sleeve 62, a buffer spring 64 fixedly installed inside the fixed sleeve 62 and fixedly connected to the top of the movable rod 63, and a support foot 65 fixedly connected to the bottom of the movable rod 63. The design of the buffer support leg assemblies 6 provides effective buffer support between the bottom of the pipeline 1 and the seabed, preventing damage to the pipeline 1 from direct impact with the seabed due to turbulence during towing, reducing the risk of the pipeline 1 sinking to the seabed, improving the safety and stability of towing, and adapting to towing needs under different seabed terrain conditions. The buffer outrigger assembly 6 is fixed to the pipe 1 via the connector 61. When the pipe 1 encounters protrusions or depressions in the seabed during towing, the support leg 65 first contacts the seabed, the movable rod 63 slides in the fixed sleeve 62, and the buffer spring 64 extends and retracts accordingly. The elastic deformation of the spring absorbs and buffers the impact force, thereby achieving buffer support between the pipe 1 and the seabed.

[0030] To enable the support leg 65 to adapt to the seabed, the support leg 65 consists of a ball seat 651 and a ball 652 rotatably embedded in the top of the ball seat 651, with the ball 652 fixedly connected to the bottom of the movable rod 63. This allows the support leg 65 to flexibly adapt to various seabed topography, including protrusions, depressions, and inclinations, ensuring support stability and preventing displacement or damage to the pipeline 1 due to uneven stress caused by uneven terrain, further improving the applicability of the device in complex seabed environments. During the towing of the subsea pipeline 1 off the seabed, when the device encounters protrusions, depressions, or inclinations in the seabed topography, the support leg 65 of the buffer leg assembly 6 will first contact the terrain. If there is a height difference in the terrain, the movable rod 63 slides within the fixed sleeve 62, and the buffer spring 64 extends and retracts to achieve adaptive adjustment of the height difference; if the terrain is inclined, the ball seat 651 and the ball 652 rotatably embedded on its top can rotate relative to each other, adjusting the contact angle of the support foot 65 within a certain range, so that the ball seat 651 can always maintain good contact with the seabed terrain at different inclination angles, thereby adapting to terrain changes.

[0031] To increase the contact area between the ball seat 651 and the seabed, a sled 66 is fixedly connected to the bottom of the ball seat 651. This increases the contact area between the ball seat 651 and the seabed, reduces the pressure of the support legs 65 on the seabed, minimizes damage to the seabed, and improves the stability of the support legs 65 on the seabed, preventing them from sinking into softer areas and ensuring the stability of the pipeline 1 during towing. The sled 66, fixedly connected to the bottom of the ball seat 651, has a larger surface area, distributing the weight of the pipeline 1 and related components over a larger area of ​​the seabed when the ball seat 651 contacts the seabed. According to the pressure formula, under constant pressure, an increased contact area results in decreased pressure, thus achieving the aforementioned beneficial effects.

[0032] To improve the buffering effect, a hydraulic damper 67 is inserted into the inner ring of the buffer spring 64. The top of the hydraulic damper 67 is fixedly connected to the top wall inside the fixed sleeve 62, and the output end of the hydraulic damper 67 is fixedly connected to the top of the movable rod 63. Through the cooperation of the hydraulic damper 67 and the buffer spring 64, the buffering effect is improved, effectively suppressing the vibration of the buffer spring 64, preventing continuous oscillation of the pipeline 1 after impact, reducing the amplitude of turbulence in the pipeline 1, and further ensuring the safety and stability of the pipeline 1 during towing. When the movable rod 63 slides within the fixed sleeve 62, the buffer spring 64 deforms, generating elastic force for buffering. Simultaneously, the output end of the hydraulic damper 67 moves with the movable rod 63, and the liquid inside the hydraulic damper 67 is compressed, generating damping force. This damping force, together with the spring force, consumes vibration energy, suppresses the reciprocating vibration of the spring, and thus enhances the buffering effect.

[0033] To improve the sealing performance between the movable rod 63 and the fixed sleeve 62, a sealing ring 631 is provided on the movable rod 63 to seal the gap between the movable rod 63 and the fixed sleeve 62. This sealing ring 631 is a sealing ring used for hydraulic cylinder piston rods, effectively improving the sealing performance between the movable rod 63 and the fixed sleeve 62, preventing seawater and impurities in the seawater from entering the interior of the fixed sleeve 62, avoiding corrosion or blockage of the buffer spring 64 and the hydraulic damper 67, ensuring their normal operation, and extending the service life of the device. The sealing ring 631, using the sealing ring for hydraulic cylinder piston rods, is installed on the movable rod 63. When the movable rod 63 slides within the fixed sleeve 62, the sealing ring 631 tightly adheres to the inner wall of the movable rod 63 and the fixed sleeve 62, sealing the gap between them and preventing seawater and impurities from entering the interior of the fixed sleeve 62.

[0034] The connector 61 includes a lower retaining ring 611 and an upper retaining ring 612 connected to the lower retaining ring 611 by bolts. Two fixing sleeves 62 are fixedly connected to both sides of the bottom of the lower retaining ring 611. This facilitates the installation and fixing of the buffer leg assembly 6 onto the pipe 1, ensuring a firm and reliable connection. It also facilitates disassembly and maintenance, and can adapt to pipes 1 of different diameters, improving the versatility and practicality of the device. The lower retaining ring 611 and the upper retaining ring 612 are connected by bolts. During installation, the lower retaining ring 611 and the upper retaining ring 612 are placed below and above the pipe 1 respectively, and then the bolts are tightened to clamp them tightly onto the pipe 1, thereby fixing the buffer leg assembly 6 onto the pipe 1. During disassembly, the connector 61 can be removed from the pipe 1 by loosening the bolts.

[0035] To prevent wear on the pipe 1 caused by the connector 61, a gasket 613 is fixedly installed on the inner side of both the lower retaining ring 611 and the upper retaining ring 612 for contact with the pipe 1. The gasket 613 is made of neoprene rubber or polyurethane toothed gasket. This prevents the lower retaining ring 611 and the upper retaining ring 612 of the connector 61 from directly contacting the pipe 1 and causing wear, protecting the outer surface of the pipe 1. At the same time, it increases the friction between the connector 61 and the pipe 1, preventing the connector 61 from sliding on the pipe 1 and ensuring the stability of the connection. The neoprene rubber or polyurethane toothed gasket also has a certain buffering effect. The gasket 613 is fixedly installed on the inner side of the lower retaining ring 611 and the upper retaining ring 612. When the connector 61 is installed on the pipe 1, the gasket 613 is between the retaining ring and the pipe 1, so that the retaining ring does not directly contact the pipe 1, thereby avoiding wear. At the same time, the material of the gasket 613 has a certain degree of elasticity and friction, which enhances the bonding force between the retaining ring and the pipe 1.

[0036] At least one buoy 5 is connected to a buoy 7, which floats on the water surface. The buoy 7 serves as a prominent marker, providing clear location information for offshore workers and facilitating rapid positioning of the pipeline 1 in complex marine environments, especially at night or in low visibility conditions. This effectively prevents collisions with other vessels, ensuring operational safety and the integrity of the pipeline 1. It also allows construction personnel to monitor and adjust the entire installation process in real time. The buoy 7 floats on the water surface by its own buoyancy and is connected to the underwater buoy 5 and pipeline 1 via a connecting device. Its conspicuous color, shape, and potential luminous or audible warning devices enable it to be spotted by workers and passing vessels from a distance. By observing the position of the buoy 7, workers can visually determine the approximate underwater location of the pipeline 1 and adjust parameters such as towing speed and direction as needed to ensure smooth installation. It also serves as a warning to surrounding vessels, preventing accidental collisions.

[0037] It also includes a lead tugboat 8, which is connected to one end of the pipeline 1 via a towing cable 9. The lead tugboat 8 provides the main traction force to the pipeline 1, propelling the pipeline 1 to move in the seawater in a predetermined direction.

[0038] It also includes a tail tugboat 10, which is connected to the other end of the pipeline 1 via a towing cable 9. When the pipeline 1 is subjected to strong lateral currents, appropriate tension can be applied to prevent the pipeline 1 from shifting or deforming excessively, ensuring the stability and straightness of the pipeline 1 during towing, improving installation accuracy, and ensuring the quality of the entire subsea pipeline 1 laying project.

[0039] The lead tugboat 8 starts its engine, generating strong traction, which is transmitted to the pipeline 1 via the tow cable 9, overcoming the resistance of the pipeline 1 in the water and moving it forward. The tail tugboat 10 monitors the force and attitude of the pipeline 1 in real time. When the lateral current exerts a force on the pipeline 1, causing the pipeline 1 to deviate or deform, the tail tugboat 10 adjusts its own position and the tension of the tow cable 9 to generate a pulling force opposite to the lateral current force, balancing the lateral force and maintaining the straightness of the pipeline 1. This ensures that the pipeline 1 can still be stably towed to the predetermined location for installation even in complex ocean current environments.

[0040] When the buoyancy of the pontoon 5 equals the weight of the pipe 1, the pipe 1 achieves a stable suspended state. However, this equilibrium is static, and even slight external disturbances can disrupt it, causing the pipe 1 to either float or sink, making it highly uncontrollable. Therefore, anchor chain 4 is used as the counterweight, with part of the anchor chain 4 in contact with the seabed. The seabed supports the weight of this part of the anchor chain 4. When the pipe 1 is disturbed and floats, the anchor chain on the seabed is pulled up, increasing the overall weight of the pipe 1 and forcing it to sink. When the pipe 1 is disturbed and sinks, the anchor chain is placed back on the seabed for support, decreasing the overall weight of the pipe 1 and forcing it to float. This achieves dynamic self-balancing of the pipe 1's suspension. Secondly, the anchor chain 4, with part of it in contact with the seabed, provides friction, which helps the pipe 1 maintain stability during towing under the influence of ocean currents, preventing significant deviations. The friction of the partially contacting anchor chain is also relatively small (compared to the entire anchor chain 4 contacting the seabed), allowing for towing with a small pulling force.

[0041] All components of the device have undergone anti-corrosion treatment.

[0042] It should be noted that many of the standard parts used in this application are available on the market, while non-standard parts can be specially customized. The connection method used in this application is also a very common method in the mechanical field, and will not be described in detail here.

[0043] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this application, based on the technical solution and concept of this application, should be included within the scope of protection of this application.

Claims

1. A bottom-towing anti-sinking buffer device for a submarine pipeline, comprising a pipeline (1) and a connecting cable (2) disposed above the pipeline (1), wherein a plurality of straps (3) connected to the connecting cable (2) are equally spaced along the length of the pipeline (1), and an anchor chain (4) for pulling down the pipeline (1) is connected to the bottom of the straps (3), and a buoy (5) for pulling up the pipeline (1) is disposed above the connecting cable (2); Its features are: The bottom of the pipe (1) is provided with a plurality of buffer support leg assemblies (6) at equal intervals along its length. The buffer support leg assembly (6) includes a connector (61) fixedly sleeved on the outside of the pipe (1), a fixed sleeve (62) symmetrically fixedly connected to both sides of the bottom of the connector (61), a movable rod (63) slidably inserted into the bottom of the fixed sleeve (62), a buffer spring (64) fixedly installed in the fixed sleeve (62) and fixedly connected to the top of the movable rod (63), and a support foot (65) fixedly connected to the bottom of the movable rod (63).

2. The anti-sinking buffer device for towing subsea pipelines off the seabed according to claim 1, characterized in that: The support foot (65) consists of a ball seat (651) and a ball (652) rotatably embedded on the top of the ball seat (651), and the ball (652) is fixedly connected to the bottom of the movable rod (63).

3. The anti-sinking buffer device for towing subsea pipelines off the seabed according to claim 2, characterized in that: The bottom of the ball seat (651) is fixedly connected to a sled (66).

4. The anti-sinking buffer device for towing subsea pipelines off the seabed according to claim 1, characterized in that: The inner ring of the buffer spring (64) is fitted with a hydraulic damper (67), the top of the hydraulic damper (67) is fixedly connected to the top wall inside the fixed sleeve (62), and the output end of the hydraulic damper (67) is fixedly connected to the top of the movable rod (63).

5. The anti-sinking buffer device for towing subsea pipelines off the seabed according to claim 1, characterized in that: The movable rod (63) is provided with a sealing ring (631) for sealing the gap between the movable rod (63) and the fixed sleeve (62).

6. The anti-sinking buffer device for towing subsea pipelines off the seabed according to claim 1, characterized in that: The connector (61) includes a lower retaining ring (611) and an upper retaining ring (612) connected to the lower retaining ring (611) by bolts. Two fixing sleeves (62) are fixedly connected to both sides of the bottom of the lower retaining ring (611).

7. The anti-sinking buffer device for towing subsea pipelines according to claim 6, characterized in that: The inner sides of both the lower retaining ring (611) and the upper retaining ring (612) are fixedly provided with gaskets (613) for contacting the pipe (1). The gaskets (613) are made of neoprene rubber or polyurethane toothed gaskets.

8. The anti-sinking buffer device for towing subsea pipelines according to claim 1, characterized in that: At least one of the pontoons (5) is connected to a buoy (7), which floats on the water surface.

9. The anti-sinking buffer device for towing subsea pipelines off the seabed according to any one of claims 1-8, characterized in that: It also includes a lead tugboat (8), which is connected to one end of the pipeline (1) via a towing cable (9).

10. The anti-sinking buffer device for towing subsea pipelines according to claim 9, characterized in that: It also includes a tail tug (10), which is connected to the other end of the pipe (1) via the towing cable (9).

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