Self-installing compliant single-point mooring module and its usage method

Abstract

This invention provides a self-installing compliant single-point mooring module and its usage method, comprising an outer buoy, an inner buoy, a pulley block ring array module, a suspension counterweight, a gravity anchor, and a mooring cable. The outer buoy is fitted outside the inner buoy, and the pulley block ring array module is securely installed inside the inner buoy. Both the suspension counterweight and the gravity anchor are equipped with load monitoring and ballast water control systems. The pulley block ring array module includes multiple sets of inner-biased upper pulleys and outer-biased lower swing pulleys. One end of the mooring cable is connected to the gravity anchor, and the other end sequentially passes around the inner edge of the lower swing pulley, the outer edge of the upper pulley, and the inner edge of the upper pulley before connecting to the suspension counterweight. This invention, by using an inner and outer buoy combined with a pulley block ring array module and connecting the suspension counterweight and gravity anchor with multiple sets of mooring cables, effectively suppresses mooring cable tension fluctuations, reducing the installation and maintenance difficulty and cost of the mooring system.

Description

Technical Field

[0001] This invention relates to the field of marine wind energy utilization, specifically to a self-installing compliant single-point mooring module and its usage method. Background Technology

[0002] The ocean is rich in resources, such as offshore wind energy, especially in deep-sea areas with depths exceeding 50 meters, where the potential for wind energy development is even greater. In addition, offshore photovoltaics, aquaculture, and other offshore development industries also possess economic and ecological benefits for large-scale development. In deep-sea areas, these exploitable resources are more abundant and of higher quality. To achieve larger-scale development, developing low-cost, high-performance floating wind turbines, floating photovoltaic platforms, and floating aquaculture systems—advanced equipment for offshore resource development—has become crucial. However, these floating offshore equipment systems all face a common problem: traditional catenary, tensioned, or tension leg mooring systems are too expensive and complex to install. These shortcomings hinder the commercialization of deep-sea resource development. Furthermore, these traditional mooring system solutions have poor sea condition adaptability, and the tendency for tension peaks within the mooring cables is detrimental to their lifespan.

[0003] To address the current lack of suitable mooring systems for offshore floating equipment, existing technology CN104632549B proposes a floating wind turbine mooring system, offshore wind turbine generator set, and its installation method. This system employs a structure where a rigid weight is connected to a floating foundation via cables, distributing the stress across the entire rigid weight across multiple cable anchors, thus enabling the floating foundation to remain stable in wind and waves. However, this device cannot effectively reduce tension variations within the mooring cables, resulting in limited improvement in fatigue characteristics. Although the mooring arrangement diameter is smaller than that of traditional catenary systems, the utilization rate of the sea area remains low. Existing technology CN202211625457.2 discloses a mooring device for a floating system and a floating wind turbine system. This mooring system includes a support component fixed to the seabed, a pulley system fixed inside the support component, and a counterweight that can move up and down. The mooring cable passes around the pulley system, with one end connected to the counterweight and the other end connected to the floating system on the water surface. This provides restoring stiffness to the float while maintaining the tension within the mooring cable approximately equal to the weight of the counterweight, avoiding large fluctuations in mooring cable tension under extreme conditions. However, the steel support component fixed to the seabed needs to be inserted 10-30 meters into the seabed. A single mooring system involves the installation of multiple sets of support components, making the installation process complex and relatively costly. The pulleys are fixed to the seabed support component, making maintenance and replacement difficult. Furthermore, the mooring radius is still relatively large, occupying a significant amount of sea area.

[0004] In summary, there is an urgent need in engineering for a floating equipment mooring system that has excellent fatigue characteristics, is easy to install and maintain, and is inexpensive. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a self-installing compliant single-point mooring module and its usage method.

[0006] According to the present invention, a self-installing compliant single-point mooring module includes: an outer buoy, an inner buoy, a pulley block ring array module, a suspension counterweight, a gravity anchor, and a mooring cable. The outer buoy is sleeved on the outside of the inner buoy, and the two can rotate relative to each other in the vertical direction. The pulley block ring array module is fixedly installed inside the inner buoy and can move up and down in the vertical direction. The suspension counterweight and the gravity anchor are both equipped with load monitoring and ballast water control systems.

[0007] The pulley block ring array module includes multiple sets of inner-biased upper pulleys and outer-biased lower swing pulleys. Multiple mooring cables are arranged symmetrically in the circumferential direction. One end of each mooring cable is connected to the gravity anchor, and the other end passes sequentially around the inner edge of the lower swing pulley, the outer edge of the upper pulley, and the inner edge of the upper pulley to connect with the suspension counterweight.

[0008] Preferably, the main body of the outer buoy is a circular cylindrical structure, with a heave suppression structure arranged circumferentially on the outer bottom edge and a mooring cable anti-wear device arranged circumferentially on the inner bottom edge. The mooring cable anti-wear device extends downward from the inner wall of the outer buoy, and its inner diameter gradually increases.

[0009] The main body of the inner buoy is a circular columnar structure. The outer diameter of the inner buoy is smaller than the inner diameter of the outer buoy, and the height of the inner buoy is smaller than the height of the outer buoy. Neither the upper nor lower ends of the inner buoy extend beyond the outer buoy.

[0010] Preferably, the top of the outer pontoon is provided with a top limiting structure along the circumferential direction, and a first groove is provided below the top limiting structure along the circumferential direction, and a plurality of top sliding rollers are arranged in the first groove;

[0011] The inner pontoon has a top support structure arranged circumferentially along its top outer edge. The top support structure is embedded in the first groove and is vertically arranged on the top sliding roller. There is a gap between the top limiting structure and the top support structure.

[0012] The outer buoy has a second groove along the circumferential direction at the center of its inner edge, and a plurality of central rotating rollers are arranged in the second groove. The inner buoy has a central bearing structure along the circumferential direction at the center of its outer edge, and the central bearing structure is in horizontal circumferential contact with the central rotating rollers.

[0013] Preferably, the main body of the pulley block annular array module is an annular columnar structure, the outer diameter of the main body is smaller than the inner diameter of the inner float, and the pulley block annular array module includes multiple sets of upper pulleys, lower swing pulleys and connecting structures arranged at equal intervals along the circumference, and the number of sets is greater than or equal to 1.

[0014] The outer edge of the upper pulley and the inner edge of the corresponding lower swing pulley are on the same vertical projection point. The mooring cable between the outer edge of the upper pulley and the inner edge of the corresponding lower swing pulley is in a vertical state. The main body of the pulley group ring array module has a through hole that runs vertically through the projection point. The mooring cable between the inner edge of the upper pulley and the suspended counterweight is in a vertical state.

[0015] Preferably, the inner buoy has multiple bottom support structures spaced circumferentially along its inner bottom edge, and each bottom support structure corresponds to a connecting structure. Each bottom support structure has a connecting hole, and the bottom support structure is fastened to the connecting structure through the connecting hole. The lower swing pulley can pass through the gap between two adjacent bottom support structures.

[0016] Preferably, the suspended counterweight is provided with multiple watertight compartments along the circumference, with a fixed ballast tank at the bottom and a variable ballast tank at the top. The variable ballast tank is connected to the ballast pump on the outer buoy via a hose.

[0017] The gravity anchor is equipped with multiple watertight compartments along the circumference inside, with a variable ballast compartment at the top and a fixed ballast compartment at the bottom;

[0018] The weight of the suspended counterweight does not exceed the buoyancy range of the outer buoy, and the weight of the gravity anchor is greater than the weight of the suspended counterweight.

[0019] According to the present invention, a method for using a self-installing compliant single-point mooring module is provided. The method comprises the following stages:

[0020] Installation phase, load adjustment phase, maintenance phase.

[0021] Preferably, the installation phase includes the following steps:

[0022] Step 101: The outer buoy and the inner buoy are constructed and joined together at the dock. The pulley block ring array module is lifted by the dock crane and docked with the inner buoy for installation.

[0023] Step 102: The suspended counterweight with emptied ballast water is suspended and fixed inside the inner buoy, and the gravity anchor with emptied ballast water is suspended and fixed close to the bottom of the outer buoy. The entire device is towed to the designated installation area by a tugboat. During the towing process, the gravity anchor and the suspended counterweight can lower the overall center of gravity of the device by increasing the internal ballast water.

[0024] Step 103: After arriving at the designated sea area, first adjust the weight of the ballast water contained in the gravity anchor until its own weight is greater than its own buoyancy, then release the fixed connection between the gravity anchor and the outer buoy and drop the gravity anchor into the seabed.

[0025] Step 104: After the gravity anchor is completely stable on the seabed, increase its ballast water content through the ballast water regulation system to increase its own weight to the specified design weight.

[0026] Step 105: Adjust the weight of ballast water contained in the suspended counterweight through the ballast water control system. When its own weight is greater than its own buoyancy, release the fixed connection between the suspended counterweight and the inner buoy, lower the suspended counterweight until the mooring cable is tensioned, control the increase of ballast water, and adjust its own weight to the design weight of the suspended counterweight.

[0027] Preferably, the load adjustment stage includes the following steps:

[0028] Step 201: The device is applied to a deep-sea floating facility. Under the operating environment, the outer buoy and the inner buoy rotate relative to each other to play a wind vane effect, so that the deep-sea floating facility always faces the incoming wind.

[0029] Step 202: The weight of ballast water contained in the suspended counterweight is adjusted according to the sea state level. When the wind and wave environment is relatively severe, the weight of ballast water is increased.

[0030] Step 203: When environmental conditions are extreme, reduce the weight of ballast water.

[0031] Preferably, the maintenance phase includes the following steps:

[0032] Step 301: The pulley block ring array module operates in an underwater environment. When maintenance is required, firstly, control the suspended counterweight to discharge some ballast water, and then use a crane located on the top working deck of the device to lift the suspended counterweight and fix it to the inner buoy.

[0033] Step 302: Release the mooring cable and the suspension counterweight from the fixation, connect the mooring cable end to the bottom of the outer buoy, and then lift the pulley block ring array module by the crane located on the top working deck of the device until the top of the pulley block ring array module is flush with the top working deck of the inner buoy and fixed to the inner buoy. Perform maintenance work on the top working deck of the inner buoy.

[0034] Step 303: After maintenance is completed, release the fixation between the pulley block annular array module and the inner buoy, lower the pulley block annular array module using the crane located on the top working deck of the device, release the connection between the mooring cable and the bottom of the outer buoy, and connect the mooring cable to the corresponding position of the suspension counterweight.

[0035] Step 304: Control the suspended counterweight to adjust the ballast water content until its own weight is greater than its own buoyancy, release the fixed connection between the suspended counterweight and the inner buoy, and lower the pulley block ring array module again until it returns to the normal working position depth, and the mooring cable is then tensioned.

[0036] Step 305: Control the suspension counterweight to draw in ballast water and adjust its own weight to the specified design weight of the suspension counterweight.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. This invention achieves relative rotation between the float and the single-point mooring module by adopting an inner and outer buoy and an adjustable-gap ring-shaped roller design. It has a simple structure, low cost, and small mooring radius, solving the problems of high cost, difficult installation, and large sea area occupation of existing mooring systems.

[0039] 2. This invention connects the gravity anchor and the suspended counterweight through multiple sets of mooring cables and pulleys, enabling the float to move in a compliant manner, reducing the tension fluctuation and breakage risk of the mooring cables. The mooring module increases the heave and pitch restoring torque of the float system, improving the stability of the system and solving the problem of balancing the fatigue strength and safety of the mooring cables with the motion performance of the float in existing technologies.

[0040] 3. By employing a pulley module, especially the swing pulley arranged at the bottom, this invention can reduce the lateral shear force exerted on the pulley by the mooring cable in the non-main motion direction, thereby reducing the probability of failure and malfunction of the underwater pulley module. In addition, the entire pulley module can be periodically raised above the water surface for maintenance, solving the problem of high failure rate and difficulty in maintenance of underwater working components in existing technologies.

[0041] 4. This invention, by adopting a modular and self-installation design, uses adjustable ballast counterweights and gravity anchors to be deployed and installed sequentially, thus solving the problems of complex installation processes, difficult maintenance, and high costs associated with existing technologies.

[0042] 5. This invention employs adjustable ballast suspension counterweights to adjust the weight, center of gravity, and tilt attitude of the suspension counterweights, ensuring equal tension in each mooring cable. This reduces the impact of seabed topographic undulations on the initial tension of the mooring cable, solving the problem of existing technologies having difficulty adjusting the pretension in mooring cables and poor adaptability to sea conditions.

[0043] 6. This invention enables low-difficulty and low-cost installation and regular maintenance of the mooring module. In addition, through the load monitoring and ballast adjustment system, the weight, center of gravity and attitude of the suspension counterweight can be automatically adjusted according to the sea state level, thereby adjusting the mooring cable tension and mooring stiffness, improving the platform's motion performance, reducing structural load, and solving the problems of complex installation process, high installation equipment requirements and costs of existing technologies. Attached Figure Description

[0044] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0045] Figure 1 This is a schematic diagram illustrating the structure of the self-installing compliant single-point mooring module, which is the main feature of this invention.

[0046] Figure 2 This is a cross-sectional view of the internal structure of the self-installing compliant single-point mooring module, which is the main feature of this invention.

[0047] Figure 3 This is a schematic diagram illustrating the internal structure of the self-installing compliant single-point mooring module, which is the main feature of this invention.

[0048] Figure 4 This is a schematic diagram illustrating the structure of the pulley system, which is the main feature of this invention.

[0049] Figure 5 This is a schematic diagram illustrating the structure of the swing pulley, which is the main feature of this invention.

[0050] Figure 6 This is a schematic diagram illustrating the working principle of the self-installing compliant single-point mooring module of the present invention.

[0051] Figure 7 This is a schematic diagram illustrating the installation process of the self-installing compliant single-point mooring module, which is the main feature of this invention.

[0052] Figure 8 This is a schematic diagram illustrating the application of the self-installing compliant single-point mooring module of the present invention to a dual-rotor floating wind turbine;

[0053] Figure 9 This is a schematic diagram illustrating a maintenance scenario for the self-installing compliant single-point mooring module, which is the main feature of this invention.

[0054] As shown in the figure:

[0055] Outer buoy 100 Top sliding roller 101

[0056] Middle rotating roller 102 Top limiting structure 103

[0057] 104 Heave suppression structure; 105 Mooring cable anti-wear device

[0058] Inner buoy 200 Top bearing structure 201

[0059] Middle load-bearing structure 202 Bottom load-bearing structure 203

[0060] Pulley block ring array module 300, upper pulley 301

[0061] Lower swing pulley 302 connecting structure 303

[0062] Suspension counterweight 400, gravity anchor 500

[0063] Mooring cable 600 Detailed Implementation

[0064] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0065] Example 1

[0066] like Figure 1-4As shown, a self-installing compliant single-point mooring module according to the present invention includes: an outer buoy 100, an inner buoy 200, a pulley block annular array module 300, a suspended counterweight 400, a gravity anchor 500, and a mooring cable 600. The outer buoy 100 is sleeved on the outside of the inner buoy 200, and the two can rotate relative to each other in the vertical direction. The pulley block annular array module 300 is fastened inside the inner buoy 200 and can move up and down in the vertical direction. The suspended counterweight 400... Both the 00 and the gravity anchor 500 are equipped with load monitoring and ballast water control systems; the pulley block ring array module 300 includes multiple sets of inner-biased upper pulleys 301 and outer-biased lower swing pulleys 302, and multiple mooring cables 600 are arranged symmetrically in the circumferential direction. One end of the mooring cable 600 is connected to the gravity anchor 500, and the other end passes through the inner edge of the lower swing pulley 302, the outer edge of the upper pulley 301, and the inner edge of the upper pulley 301 in sequence to connect with the suspension counterweight 400.

[0067] The device of the present invention includes a load monitoring and ballast water adjustment system, which can monitor the tension in each mooring cable 600, the ballast water content in the suspension counterweight 400 and the gravity anchor 500 in real time, and adjust the ballast water content in the suspension counterweight 400 and the gravity anchor 500 in real time.

[0068] This invention employs a modular mooring device consisting of an outer buoy 100, an inner buoy 200, multiple pulley blocks, a mooring cable 600, and an adjustable ballast counterweight. This device can suppress excessive fluctuations in mooring cable tension and achieve compliant movement of the float. It solves the problem of high fatigue failure risk due to large fluctuations in mooring cable tension in existing methods. Furthermore, the mooring radius is smaller than that of existing methods, requiring less sea area and conforming to the policy of intensive use of the sea.

[0069] This invention employs a design with two sets of internal and external counterweights and multiple sets of fixed pulleys. This design effectively improves the horizontal restoring force of the mooring system while enabling compliant movement of the floating body under external environmental loads, thus enhancing the in-plane positional stability of the surface floating body. The invention utilizes an adjustable ballast suspension counterweight of 400 and proposes a modular installation and operation method based on ballast adjustment. This enables low-cost, low-threshold installation of the mooring modules, reducing the construction and installation costs of the mooring system. It exhibits high adaptability to seabed topography and can automatically adjust the pretension of the mooring cable according to sea state levels, improving the adaptability of the floating system to different sea state levels and enhancing the motion performance of the surface floating body.

[0070] The outer buoy 100 is a rotating structure with a central through-hole. Its main body is a circular columnar structure, and a circumferentially continuous heave suppression structure 104 is provided along the outer edge of the bottom to improve the hydrodynamic performance of the device of the present invention. A mooring cable anti-wear device 105 is provided along the inner edge of the bottom. The mooring cable anti-wear device 105 extends downward from the inner wall of the outer buoy 100 at an angle, and its inner diameter gradually increases. That is, the bottom opening of the outer buoy 100 has an inclined transition and appropriate expansion, which can avoid interference with external mooring.

[0071] The inner pontoon 200 has a main body that is a circular columnar structure approximately the same shape as the outer pontoon 100. The outer diameter of the inner pontoon 200 is slightly smaller than the inner diameter of the outer pontoon 100, allowing the outer pontoon 100 to accommodate the inner pontoon 200 and preventing friction when the inner pontoon 200 and the outer pontoon 100 rotate relative to each other under working conditions. The height of the inner pontoon 200 is less than the height of the outer pontoon 100, and neither the upper nor lower ends of the inner pontoon 200 extend beyond the outer pontoon 100. This ensures that the inner pontoon 200 is completely protected by the outer pontoon 100, thereby protecting the pulley block annular array module 300 and reducing the risk of damage to the device of the present invention.

[0072] A top limiting structure 103 is arranged circumferentially along the top of the outer pontoon 100 along the annular deck. A first groove is provided circumferentially below the top limiting structure 103, and multiple top sliding rollers 101 are arranged circumferentially within the first groove. The top sliding rollers 101 can roll along the inner circumferential edge of the top of the outer pontoon 100. A continuous top bearing structure 201 is provided circumferentially along the outer edge of the top of the inner pontoon 200. The outer diameter of the top bearing structure 201 is larger than the inner diameter of the outer pontoon 100. The top bearing structure 201 is embedded in the first groove, thus allowing the outer pontoon 100 to support the inner pontoon 200 and partially share its own weight. Furthermore, the top bearing structure 201 is vertically positioned on the top sliding rollers 101, which support the inner pontoon 200 and allow it to rotate freely relative to the outer pontoon 100. The top limiting structure 103 ensures that the top bearing structure 201 cannot displace too much upward and detach from the outer float 100 during operation. There is a certain gap between the top limiting structure 103 and the top bearing structure 201 to ensure that no friction is generated when the inner float 200 and the outer float 100 rotate relative to each other under working conditions.

[0073] A second groove is provided circumferentially at the center of the inner edge of the outer float 100, and multiple central rotating rollers 102 are arranged in the second groove. The central rotating rollers 102 can roll along the horizontal circumferential line of the inner edge of the outer float 100. A protruding central bearing structure 202 is provided circumferentially at the center of the outer edge of the inner float 200. The central bearing structure 202 and the central rotating rollers 102 are in horizontal circumferential contact. The gap between the two should be smaller than the gap between the inner float 200 and the outer float 100, so as to further ensure that the inner float 200 and the outer float 100 can rotate freely relative to each other under working conditions, and further avoid large-area contact friction between the inner float 200 and the outer float 100.

[0074] like Figure 5 As shown, the main body of the pulley block annular array module 300 is an annular columnar structure. The outer diameter of the main body is slightly smaller than the inner diameter of the inner float 200, allowing the inner float 200 to accommodate the pulley block annular array module 300. The pulley block annular array module 300 includes multiple sets of upper pulleys 301, lower swing pulleys 302, and connecting structures 303 arranged at equal intervals along the circumference, with the number of sets being greater than or equal to 3. In this embodiment, 8 sets are used as an example.

[0075] The upper pulley 301 and the lower swing pulley 302 should be arranged at the same position on the circumference, and the horizontal rotation envelope of the lower swing pulley 302 should avoid interference with the inner edge of the inner float 200. In addition to its own rotation, the lower swing pulley 302 can also deflect around a vertical axis to avoid applying excessive lateral shear force to the lower pulley during operation of the device. The outer edge of each set of upper pulleys 301 and the inner edge of its corresponding lower swing pulley 302 are located at approximately the same vertical projection point, and the mooring cable 600 between the outer edge of the upper pulley 301 and the inner edge of its corresponding lower swing pulley 302 is vertical. The main body of the pulley group annular array module 300 has a through hole at the projection point, allowing the mooring cable 600 to smoothly pass around the upper pulley 301 and connect to the lower swing pulley 302 through the through hole. The mooring cable 600 between the inner edge of the upper pulley 301 and the suspended counterweight 400 is vertical.

[0076] Multiple protruding bottom support structures 203 are spaced circumferentially along the inner bottom edge of the inner float 200 to vertically support the pulley block annular array module 300. Each bottom support structure 203 corresponds one-to-one with a connecting structure 303, which can reduce the number of bottom support structures 203 in practical applications. Each bottom support structure 203 has a connecting hole, through which it is securely connected to the connecting structure 303, preventing relative rotation between the inner float 200 and the pulley block annular array module 300 under working conditions. Sufficient space should be maintained between the bottom support structures 203 of the inner float 200 to allow the lower swing pulley 302 to pass through the gap between adjacent bottom support structures 203 when the pulley block annular array module 300 is vertically lifted upwards during maintenance.

[0077] The device of this invention includes several mooring cables 600, the number of which should be consistent with the number of the upper pulley 301; in this embodiment, it is eight. One end of each mooring cable 600 is connected to a gravity anchor 500 located on the seabed, and passes successively through the inner side of the lower swing pulley 302, a through hole, the outer side of the upper pulley 301, and the inner side of the upper pulley 301; the other end is connected to the suspended counterweight 400. The eight mooring cables 600 are arranged symmetrically around the circumference, jointly suspending the suspended counterweight 400.

[0078] The preferred material for the mooring cable 600 is synthetic fiber cable (aramid, polyethylene, HMPE, carbon fiber, nylon, etc.). Alternatively, seawater corrosion-resistant steel wire rope can also be used.

[0079] like Figure 6 As shown, the suspended ballast 400 has multiple watertight compartments arranged circumferentially inside, which can be used to adjust the weight, center of gravity, and attitude of the ballast using ballast water. This addresses the impact of uneven seabed on the lengths of different mooring cables 600, ensuring that the initial tension of each mooring cable 600 is equal. The bottom of the suspended ballast 400 is a fixed ballast tank, and the top is a variable ballast tank. Fixed ballast materials can be iron sand, steel blocks, concrete, etc.; the variable ballast tank of the ballast 400 is connected to the ballast pump arranged on the outer buoy 100 via a hose.

[0080] The gravity anchor 500 can be a traditional gravity anchor, with filling materials including iron sand, iron blocks, concrete, or a mixture of materials. Optionally, the gravity anchor 500 can also have multiple watertight compartments arranged circumferentially inside, with a fixed ballast tank at the bottom and a variable ballast tank at the top, allowing the weight of the gravity anchor 500 to be adjusted using ballast water. Furthermore, a suction anchor device can be locally added to the bottom of the gravity anchor, providing a secure connection to the seabed through negative pressure. Additionally, a protruding structure with ground-breaking capabilities can be added to the bottom of the gravity anchor to increase the horizontal friction between the gravity anchor and the seabed.

[0081] The weight of the suspension counterweight 400 determines the pretension of the mooring cable 600 and the effectiveness of the device of the present invention. It should be sufficient in weight but should not exceed the buoyancy range provided by the outer buoy 100. The weight of the gravity anchor 500 should be greater than the weight of the suspension counterweight 400, with a certain safety margin to prevent the gravity anchor 500 from being pulled up. In this embodiment, the gravity anchor 500 is a single piece; in other embodiments, it can be divided into multiple pieces depending on the number of mooring cables 600.

[0082] The mooring cable 600 can be divided into three sections according to the connection nodes: section 1: from the gravity anchor 500 to the lower swing pulley 302; section 2: from the lower swing pulley 302 to the upper pulley 301; and section 3: from the upper pulley 301 to the suspended counterweight 400. When the device is in its balanced position without external environmental disturbance, sections 2 and 3 are vertically arranged, while section 1 has a certain tilt angle to provide better mooring recovery stiffness. The tilt angle is preferably within 15 degrees of the vertical direction. Both the gravity anchor 500 and the suspended counterweight 400 are adjustable weights; in this embodiment, both can be increased / decreased by drawing in / draining ballast water.

[0083] The 400mm counterweight, when moving up and down, also provides the advantages of damping and additional mass, which can increase the mooring restoring force of the device of the present invention. Furthermore, the device of the present invention can provide additional restoring torque for the motion of the buoy, such as heave and pitch, increasing system stability.

[0084] The device of this invention can be connected to deep-sea floating facilities such as barges, floating wind turbines, and floating aquaculture cages.

[0085] This application achieves relative rotation between the floating body and the single-point mooring module by adopting an inner and outer buoy and an adjustable-gap ring-shaped roller design. It has a simple structure, low cost, and small mooring radius, solving the problems of high cost, difficult installation, and large sea area occupation of existing mooring systems.

[0086] This application connects the gravity anchor 500 and the suspended counterweight 400 through multiple sets of mooring cables 600 and pulleys, which enables the float to move in a compliant manner, reduces the tension fluctuation and breakage risk of the mooring cables 600, and increases the heave and pitch recovery torque of the float system by the mooring module, thereby improving the stability of the system and solving the problem that existing technologies cannot balance the fatigue strength safety of the mooring cables with the motion performance of the float.

[0087] This application, by employing a pulley module, especially the lower swing pulley 302 arranged at the bottom, can reduce the lateral shear force exerted on the pulley by the mooring cable 600 in the non-main motion direction, thereby reducing the probability of failure and malfunction of the underwater pulley module. In addition, the entire pulley module can be periodically raised above the water surface for maintenance, solving the problem of high failure rate and difficulty in maintenance of underwater working components in existing technologies.

[0088] This application employs an adjustable ballast suspension counterweight 400 to adjust the weight, center of gravity, and tilt attitude of the suspension counterweight, thereby ensuring equal tension within each mooring cable 600. This reduces the impact of seabed topographic undulations on the initial tension of the mooring cable 600 and solves the problem of poor sea condition adaptability caused by existing technical methods in adjusting the pretension of the mooring cable 600.

[0089] Example 2

[0090] like Figure 7-9 As shown, a method for using a self-installing compliant single-point mooring module according to the present invention, which is the installation, maintenance and load adjustment method of the self-installing compliant single-point mooring module of Embodiment 1, includes the following stages:

[0091] Installation phase, load adjustment phase, maintenance phase.

[0092] The installation phase includes the following steps:

[0093] Step 101: The outer buoy 100 and inner buoy 200 of the device of the present invention are constructed and joined together at the dock. The pulley block ring array module 300 is lifted by the dock crane and docked with the inner buoy 200.

[0094] Step 102: Suspend and fix the ballast-emptying ballast water-discharged ballast weight 400 inside the inner buoy 200, and suspend and fix the ballast-emptying ballast water-discharged gravity anchor 500 close to the bottom of the outer buoy 100. Then, tow the entire device of the present invention to the designated installation area using a tugboat. During towing, the gravity anchor 500 and the ballast water-discharged ballast weight 400 can lower the overall center of gravity of the device of the present invention by increasing the internal ballast water, thereby improving stability during towing.

[0095] Step 103: After arriving at the designated sea area, first adjust the weight of the ballast water contained in the gravity anchor 500. When its own weight is slightly greater than its own buoyancy, release the fixed connection between the gravity anchor 500 and the outer buoy 100, and slowly drop the gravity anchor 500 into the seabed.

[0096] Step 104: After the gravity anchor 500 is completely stable on the seabed, increase its ballast water content through the ballast water regulation system to increase its own weight to the specified design weight.

[0097] Step 105: Adjust the weight of ballast water contained in the suspension counterweight 400 through the ballast water control system. When its own weight is slightly greater than its own buoyancy, release the fixed connection between the suspension counterweight 400 and the inner float 200, and slowly lower the suspension counterweight 400 until the mooring cable 600 is tensioned. Control the increase of ballast water and adjust its own weight to the design weight of the suspension counterweight 400.

[0098] This application solves the problems of complex installation process, difficult maintenance and high cost of existing technology methods by adopting a modular and self-installation design and using adjustable ballast suspension counterweight 400 and gravity anchor 500 to be deployed and installed in sequence.

[0099] The load conditioning phase includes the following steps:

[0100] Step 201: The device is applied to deep-sea floating facilities. In this embodiment, it is applied to a dual-rotor floating wind turbine as an example. Under the working environment, the outer float 100 can rotate relative to the inner float 200 to play the role of a wind vane, so that the wind turbine always keeps facing the incoming wind.

[0101] Step 202: The weight of ballast water contained in the suspension counterweight 400 can be adjusted according to the sea state. When the wind and wave environment is relatively severe, the weight of ballast water can be increased to improve the pretension of the mooring cable and provide higher mooring recovery stiffness.

[0102] Step 203: When environmental conditions are extreme, the weight of ballast water can be reduced to improve system compliance and reduce ultimate load.

[0103] The purpose of this method is to control the tension of the mooring cable 600 to prevent overload breakage. During operation, the device requires real-time monitoring of the mooring cable 600 tension and the buoy's movement amplitude, dynamically adjusting the ballast water within the suspended counterweight 400. A control strategy can be designed based on the buoy's movement amplitude to achieve a balance between the buoy's movement amplitude and the mooring cable 600 tension.

[0104] The maintenance phase includes the following steps:

[0105] Step 301: The pulley block ring array module 300 of the device of the present invention is working in an underwater environment. When maintenance is required, the suspension counterweight 400 is first controlled to discharge part of the ballast water. The suspension counterweight 400 is then lifted by a crane located on the top working deck of the device of the present invention and fixedly connected to the inner buoy 200.

[0106] Step 302: Release the mooring cable 600 and the suspension counterweight 400 from their fixed positions, connect the mooring cable 600 to the bottom of the outer buoy 100, and then use a crane located on the top working deck of the device of the present invention to lift the pulley block ring array module 300 until the top of the pulley block ring array module 300 is flush with the top working deck of the inner buoy 200 and fixed to the inner buoy 200. Maintenance personnel can then perform maintenance work on the top working deck of the inner buoy 200.

[0107] Step 303: After maintenance, release the fixation between the pulley block annular array module 300 and the inner buoy 200, and lower the pulley block annular array module 300 using a crane located on the top working deck of the device. Release the connection between the mooring cable 600 and the bottom of the outer buoy 100, and connect that end of the mooring cable 600 to the corresponding position of the suspended counterweight 400.

[0108] Step 304: Control the suspension counterweight 400 to adjust the ballast water content until its own weight is slightly greater than its own buoyancy, release the fixed connection between the suspension counterweight 400 and the inner buoy 200, and lower the pulley block ring array module 300 again until it returns to the normal working position depth, and the mooring cable 600 is then tensioned.

[0109] Step 305: Control the suspension counterweight 400 to draw in ballast water and adjust its own weight to the design weight of the suspension counterweight 400.

[0110] Based on the aforementioned self-installing compliant single-point mooring module, a method for installation, maintenance, and load adjustment combining load monitoring and ballast adjustment functions is proposed. This method enables low-difficulty and low-cost installation and regular maintenance of the mooring module. Furthermore, through the load monitoring and ballast adjustment system, the weight, center of gravity, and attitude of the suspended counterweight can be automatically adjusted according to the sea state, thereby adjusting the mooring cable tension and mooring stiffness, improving the platform's motion performance, reducing structural load, and solving the problems of complex installation processes, high equipment requirements, and high costs associated with existing technologies.

[0111] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0112] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A self-installing compliant single-point mooring module, characterized in that, include: The system includes an outer buoy (100), an inner buoy (200), a pulley block ring array module (300), a suspension counterweight (400), a gravity anchor (500), and a mooring cable (600). The outer buoy (100) is sleeved on the outside of the inner buoy (200), and the two can rotate relative to each other in the vertical direction. The pulley block ring array module (300) is fixedly installed inside the inner buoy (200) and can move up and down in the vertical direction. The suspension counterweight (400) and the gravity anchor (500) are both equipped with load monitoring and ballast water control systems. The pulley block ring array module (300) includes multiple sets of inner-biased upper pulleys (301) and outer-biased lower swing pulleys (302). Multiple mooring cables (600) are arranged symmetrically in the circumferential direction. One end of the mooring cable (600) is connected to the gravity anchor (500), and the other end passes through the inner edge of the lower swing pulley (302), the outer edge of the upper pulley (301), and the inner edge of the upper pulley (301) in sequence and is connected to the suspension counterweight (400). The main body of the pulley group annular array module (300) is an annular columnar structure. The outer diameter of the main body is smaller than the inner diameter of the inner float (200). The pulley group annular array module (300) includes multiple sets of upper pulleys (301), lower swing pulleys (302) and connecting structures (303) arranged at equal intervals along the circumference, and the number of sets is greater than or equal to 3. The outer edge of the upper pulley (301) and the inner edge of its corresponding lower swing pulley (302) are on the same vertical projection point. The mooring cable (600) between the outer edge of the upper pulley (301) and the inner edge of its corresponding lower swing pulley (302) is in a vertical state. The main body of the pulley group ring array module (300) has a through hole that runs vertically through the projection point. The mooring cable (600) between the inner edge of the upper pulley (301) and the suspended counterweight (400) is in a vertical state. The inner float (200) has multiple bottom support structures (203) spaced circumferentially along its bottom inner edge. Each bottom support structure (203) corresponds to a connecting structure (303). Each bottom support structure (203) has a connecting hole. The bottom support structure (203) is fastened to the connecting structure (303) through the connecting hole. The lower swing pulley (302) can pass through the gap between two adjacent bottom support structures (203).

2. The self-installing compliant single-point mooring module according to claim 1, characterized in that, The main body of the outer buoy (100) is a circular columnar structure. A heave suppression structure (104) is provided along the circumferential direction on the outer edge of the bottom, and a mooring cable anti-wear device (105) is provided along the circumferential direction on the inner edge of the bottom. The mooring cable anti-wear device (105) extends downward from the inner wall of the outer buoy (100) and its inner diameter gradually increases. The main body of the inner buoy (200) is a circular columnar structure. The outer diameter of the inner buoy (200) is smaller than the inner diameter of the outer buoy (100). The height of the inner buoy (200) is smaller than the height of the outer buoy (100). Neither the upper nor lower ends of the inner buoy (200) extend beyond the outer buoy (100).

3. The self-installing compliant single-point mooring module according to claim 1, characterized in that, The top of the outer float (100) is provided with a top limiting structure (103) along the circumferential direction, and a first groove is provided below the top limiting structure (103) along the circumferential direction, and a plurality of top sliding rollers (101) are arranged in the first groove. The inner float (200) has a top support structure (201) arranged circumferentially on the outer edge of the top. The top support structure (201) is embedded in the first groove and is vertically arranged on the top sliding roller (101). There is a gap between the top limiting structure (103) and the top support structure (201). The outer float (100) has a second groove in the middle of its inner edge along the circumferential direction, and a plurality of central rotating rollers (102) are arranged in the second groove. The inner float (200) has a central bearing structure (202) in the middle of its outer edge along the circumferential direction, and the central bearing structure (202) is in horizontal circumferential contact with the central rotating rollers (102).

4. The self-installing compliant single-point mooring module according to claim 1, characterized in that, The suspended counterweight (400) is equipped with multiple watertight compartments along the circumference inside. The bottom is a fixed ballast tank and the top is a variable ballast tank. The variable ballast tank is connected to the ballast pump on the outer buoy (100) through a hose. The gravity anchor (500) has multiple watertight compartments arranged circumferentially inside, with a variable ballast compartment at the top and a fixed ballast compartment at the bottom; The weight of the suspension counterweight (400) does not exceed the buoyancy range of the outer pontoon (100), and the weight of the gravity anchor (500) is greater than the weight of the suspension counterweight (400).

5. A method for using a self-installing compliant single-point mooring module, characterized in that, The method of use is the installation, maintenance, and load adjustment method for the self-installing compliant single-point mooring module as described in any one of claims 1 to 4, comprising the following stages: Installation phase, load adjustment phase, maintenance phase.

6. The method of using the self-installing compliant single-point mooring module according to claim 5, characterized in that, The installation phase includes the following steps: Step 101: The outer buoy (100) and the inner buoy (200) are constructed and joined together at the dock. The pulley block ring array module (300) is lifted by the dock crane and docked with the inner buoy (200) for installation. Step 102: The suspended counterweight (400) with ballast water emptied is suspended and fixed inside the inner buoy (200), and the gravity anchor (500) with ballast water emptied is suspended and fixed close to the bottom of the outer buoy (100). The entire device is towed to the designated installation area by a tugboat. During the towing process, the gravity anchor (500) and the suspended counterweight (400) can lower the overall center of gravity of the device by increasing the internal ballast water. Step 103: After arriving at the designated sea area, first adjust the weight of the ballast water contained in the gravity anchor (500). When its own weight is greater than its own buoyancy, release the fixed connection between the gravity anchor (500) and the outer buoy (100) and drop the gravity anchor (500) into the seabed. Step 104: After the gravity anchor (500) is completely stable on the seabed, increase its ballast water content through the ballast water regulation system to increase its own weight to the specified design weight. Step 105: Adjust the weight of ballast water contained in the suspended counterweight (400) through the ballast water control system. When its own weight is greater than its own buoyancy, release the fixed connection between the suspended counterweight (400) and the inner buoy (200), lower the suspended counterweight (400) until the mooring cable (600) is tensioned, control it to increase ballast water, and adjust its own weight to the design weight of the suspended counterweight (400).

7. The method of using the self-installing compliant single-point mooring module according to claim 5, characterized in that, The load adjustment stage includes the following steps: Step 201: The device is applied to a deep-sea floating facility. Under the operating environment, the outer buoy (100) and the inner buoy (200) rotate relative to each other to play a wind vane effect, so that the deep-sea floating facility always faces the incoming wind. Step 202: The weight of ballast water contained in the suspended counterweight (400) is adjusted according to the sea state level. When the wind and wave environment is relatively severe, the weight of ballast water is increased. Step 203: When environmental conditions are extreme, reduce the weight of ballast water.

8. The method of using the self-installing compliant single-point mooring module according to claim 5, characterized in that, The maintenance phase includes the following steps: Step 301: The pulley block ring array module (300) is working in an underwater environment. When maintenance is required, the suspended counterweight (400) is first controlled to discharge part of the ballast water. The suspended counterweight (400) is then lifted by a crane located on the top working deck of the device and fixedly connected to the inner buoy (200). Step 302: Release the mooring cable (600) and the suspension counterweight (400) from their fixed positions, connect the mooring cable (600) to the bottom of the outer buoy (100) at one end, and then lift the pulley block ring array module (300) using a crane located on the top working deck of the device until the top of the pulley block ring array module (300) is flush with the top working deck of the inner buoy (200) and fixed to the inner buoy (200). Perform maintenance work on the top working deck of the inner buoy (200). Step 303: After maintenance is completed, release the fixation between the pulley block annular array module (300) and the inner buoy (200), lower the pulley block annular array module (300) using a crane located on the top working deck of the device, release the connection between the mooring cable (600) and the bottom of the outer buoy (100), and connect the mooring cable (600) to the corresponding position of the suspension counterweight (400); Step 304: Control the suspended counterweight (400) to adjust the ballast water content until its own weight is greater than its own buoyancy, release the fixed connection between the suspended counterweight (400) and the inner buoy (200), lower the pulley block ring array module (300) again until it returns to the normal working position depth, and the mooring cable (600) is then tensioned. Step 305: Control the suspension counterweight (400) to draw in ballast water and adjust its own weight to the specified design weight of the suspension counterweight (400).

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