Gravity-type adjustable-length seabed single-point mooring connection device for floating wind power durbins

Abstract

The gravity-type adjustable-length seabed single-point mooring connection device for a floating wind turbine includes a float with at least two pulley fairleads, a single-point anchor installed on the seabed and connected to a rotatable device, and at least one canter weight located underwater below the float, the canter weight and the single-point anchor being connected by a mooring line passing through the pulley fairlead. The present invention has a small seabed coverage area, is environmentally friendly, has a high mooring system efficiency, has a wind vane function, is safer, more reliable, practical, and feasible, and can be used for offshore mooring and positioning of floating wind power platforms in water depths of 50 meters to 300 meters, and even over 1,500 meters.

Description

[Technical Field]

[0001] The present invention relates to technology in the field of marine engineering structures, in particular to a gravity-type variable-length subsea single-point mooring connection device that can be used for floating offshore wind power platforms in water depths of 50 meters to 300 meters, and even more than 1500 meters. [Background technology]

[0002] Existing mooring and positioning technologies for floating offshore structures include catenary mooring, tension (or semi-tension) outrigger, and tension leg mooring. Catenary moorings, among others, require a large seabed footprint (coverage area), significantly impacting the water and seabed environment. In deep waters, steel mooring lines are too heavy and cost prohibitive. In waters less than 100 meters deep, the shallow depth prevents mooring cables and chains from forming a catenary shape long enough to connect the mooring point on the float to the anchor point on the seabed. This prevents them from providing the necessary restoring force to limit the horizontal movement of floating offshore structures under the action of wind, waves, currents, and other external forces. Therefore, mooring positioning capabilities are poor in shallow waters, and the length of the mooring chain required on the seabed is typically several times the water depth. Offshore installation is difficult, time-consuming, and costly. The dynamic tension of catenary mooring cables increases exponentially with increasing horizontal movement of the floating offshore structure, posing significant challenges to the design of mooring systems, including issues of mooring cable strength and fatigue.

[0003] Existing mooring and positioning methods for offshore floating wind turbines are primarily achieved by a mooring system consisting of multiple anchors distributed on the seabed and connected mooring cables / chains. The multiple anchors on the seabed are distributed, and the mooring points on the floater (floating wind turbine) are also distributed around the outside of the floating wind turbine's foundation, allowing it to withstand wind and wave forces from all directions. The drawback of this method is the low mooring effectiveness of the mooring system. In particular, the anchors fixed to the seabed can only resist external wind and wave forces from one direction, i.e., from the anchor points on the seabed toward the mooring points on the floater. If external forces are applied from other directions, the anchors on the mooring cables will no longer function effectively.

[0004] Existing single-point mooring technology is primarily applied to offshore floating oil and gas production, storage, and offloading facilities. Specifically, multiple mooring lines are connected to mooring points on the float, i.e., multiple anchors distributed on the seafloor are connected to a single rotating single-point mooring connection device on the float with a wind vane function via mooring lines. In this way, the floating oil and gas production, storage, and offloading facility can rotate around the single-point mooring connection device as the direction of external forces (wind, waves, and current) changes, and the bow always faces the direction of the external forces, thereby playing an excellent role in mitigating wind and wave forces. However, the single-point mooring connection device installed on the vessel (floor) is very complex and expensive. The mooring system uses a multi-anchor system distributed on the seafloor, resulting in low mooring efficiency.

[0005] Existing floating platform positioning technologies using pontoons cannot withstand harsh environments. For example, typhoons cause violent movements due to waves, leading to fatigue failure of the frame structure. Because pontoons are subject to large displacements due to the effects of waves, even strengthening the frame structure (which significantly increases costs) cannot provide effective positioning function for the target floating platform. Existing technologies based on underwater anchors cannot provide effective positioning of the target floating platform; they can only limit the position in one dimension. Mooring systems are ineffective and cannot provide wind vane function. Summary of the Invention [Problem to be solved by the invention]

[0006] Considering the design difficulties of existing catenary mooring connection devices, as well as the problems of large seabed coverage and low mooring system effectiveness caused by the distributed arrangement of multiple anchors on the seabed adopted by existing single-point mooring connection devices, this invention proposes a gravity-type variable-length seabed single-point mooring connection device for floating wind turbines, which has a small seabed coverage area, is environmentally friendly, has the function of a wind vane, and the mooring system is highly efficient, safe, reliable, practical and feasible. [Means for solving the problem]

[0007] The present invention is realized through the following technical solutions:

[0008] The present invention relates to a gravity-type adjustable-length seabed single-point mooring connection device for a floating wind turbine, which comprises a float having at least two sheave fairleads, a single-point anchor arranged on the seabed, and at least one counterweight located in the water below the float, the counterweight and the single-point anchor being connected by a mooring line passing through the sheave fairleads.

[0009] The floating structure is equipped with a wind power tower and a wind power generator.

[0010] The sheave fairleads are preferably arranged symmetrically on the outside of the floating body, and more preferably arranged symmetrically about the center.

[0011] When a single counterweight is used, it is connected to a single-point anchor placed on the seabed via at least two mooring lines, each passing through a corresponding sheave fairlead. The counterweight is located directly below the float during operation.

[0012] When the float is in its initial equilibrium position, the single-point anchor is located at the intersection of the float's vertical centerline and the seabed. The mooring points of the multiple mooring cables / chains on the float are geometrically symmetrically arranged, and counterweights are positioned vertically above the single-point anchor on the seabed and below the float.

[0013] When the float moves horizontally from its initial equilibrium position due to the action of an external force, the effective length of the mooring lines becomes variable, and the length of the mooring lines between the float's mooring point and the single-point anchor on the seabed changes in accordance with the change in the float's horizontal movement. At the same time, the counterweights move up and down and left and right, and their positions change in accordance with the change in the effective length of the corresponding mooring lines. The sum of the vertical components of the tension in all the mooring lines is equal to the weight of the counterweight. The tension in each mooring line is not constant, and a restoring force is generated in the mooring system as the angle with the water surface changes, the absolute value of which is equal to the sum of the horizontal components of the tension in all the mooring lines. This restoring force increases as the float moves. When the float's movement reaches a certain value, it becomes equal to the absolute value of the external force and its direction is reversed. When the external force is removed, the float returns to its initial position.

[0014] When two or more counterweights are used, each counterweight is connected to a single-point anchor located on the seabed via a mooring line and a corresponding sheave fairlead, and each counterweight is positioned directly below its corresponding sheave fairlead during operation.

[0015] When the float is in its initial equilibrium position, the single-point anchor is located at the geometric center of the mooring connection device on the seabed, i.e., the intersection point of the vertical centerline of the float and the seabed. The mooring points of the multiple mooring cables / chains on the float are geometrically symmetrically arranged, and the counterweights corresponding to each mooring line are positioned below the corresponding pulley fairlead and vertically on the seabed.

[0016] When a float moves horizontally from its initial equilibrium position due to external forces (wind, waves, currents), the effective length of the mooring lines between the float's mooring point and the single-point anchor on the seabed changes with the change in the float's movement, and the tension in the mooring lines is always equal to the weight of the corresponding counterweight. At this time, the tension in each mooring line is constant, but because the geometric angle with the water surface changes, a restoring force is generated in the mooring system, the absolute value of which is equal to the sum of the horizontal components of the tension in all mooring lines, and it increases as the float's movement increases. When the float's movement reaches a certain value, it becomes equal to the absolute value of the external force and reverses in direction. When the external force is removed, the float returns to its initial position.

[0017] A rotary single-point mooring connection device is provided on the top of the seabed single-point anchor, and the position of the seabed single-point anchor remains fixed while the floating body and the wind turbine above it are connected to the mooring line so that they always face the direction of the outside wind.The single-point anchor is preferably a concrete gravity anchor having a bottom skirt that is sunk below the seabed mud surface, a cross-shaped watertight longitudinal bulkhead inside it, a rotary single-point mooring connection device located in the center of the cross-shaped longitudinal bulkhead, and a bearing rotation device inside.

[0018] The present invention relates to an integrated installation method based on the gravity-type adjustable-length subsea single-point mooring connection device. After fabricating a single-point anchor and counterweight with a vertical watertight bulkhead cavity from concrete, the single-point anchor and counterweight are connected to the pier shore using a mooring line, and then temporarily connected to the wind durbin tower and the float carrying the wind turbine using a conventional lashing and fastening device for marine transportation. The entire system is towed as an integrated unit using a tugboat. Upon arriving at the offshore installation site, the single-point anchor's lashing and fastening device for marine transportation is first released, seawater is poured into the cavity, and the single-point anchor is automatically lowered to the seabed under gravity. The counterweights are then removed one by one from the lashing and fastening device for marine transportation and lowered to the desired underwater depth. The mooring lines are then tightened one by one, completing the offshore installation of the wind turbine, float, and mooring system in one go.

[0019] Maritime securing devices employ temporary connecting components such as, but not limited to, ropes. [Effects of the Invention]

[0020] Compared with the prior art, the technical advantages of the present invention are as follows: i) The present invention breaks away from the traditional fixed-length mooring method, in which the physical length of the mooring line between the mooring point on the float (e.g., a fairlead) and the anchor point on the seabed is fixed, and instead proposes a new variable-length mooring method, in which the physical length of the mooring line between the mooring point on the float (e.g., a fairlead) and the anchor point on the seabed is variable. This significantly reduces the maximum tension (static tension + dynamic tension) of the mooring line, significantly improving the safety, reliability, and fatigue life of the entire mooring system. ii) The present invention minimizes the installation area of ​​the mooring system on the seabed (only the size of the anchor), solving the problems of large-scale use of offshore floating wind turbines and shared use of marine resources, which have a significant impact on the marine ecological environment. iii) The present invention has a wind vane function, which allows the wind turbine to always face the direction of the incoming wind, significantly improving the power generation efficiency of the wind turbine. iv) The present invention can integrate the offshore installation of the wind turbine, floating body and mooring system into one installation method, thereby greatly saving the time and cost of offshore installation of the mooring system and greatly improving the offshore installation efficiency of the entire floating wind power generation system. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a two-dimensional schematic diagram of a gravity-type variable length non-constant tension subsea single point mooring connection device. [Figure 2] FIG. 1 is a two-dimensional schematic diagram showing the horizontal movement of a floating body of a gravity-type variable-length non-constant tension seabed single-point mooring connection device. [Figure 3] FIG. 1 is a three-dimensional diagram of the effect of a gravity-type variable-length non-constant tension submarine single-point mooring connection device. [Figure 4] A two-dimensional schematic drawing of the fairlead of a gravity-type variable-length non-constant tension subsea single-point mooring connection device, including partial details of the sheave, connection structure, and counterweight. [Figure 5] FIG. 1 is a three-dimensional schematic diagram showing a partial detail of a connecting plate that connects to the mooring line of the counterweight of a gravity-type variable length non-constant tension subsea single point mooring connection device. [Figure 6] FIG. 1 is a two-dimensional schematic diagram of a gravity-type variable length constant tension subsea single point mooring connection device. [Figure 7] FIG. 1 is a two-dimensional schematic diagram showing the horizontal movement of a floating body of a gravity-type variable-length constant-tension seabed single-point mooring connection device. [Figure 8] FIG. 1 is a side view showing partial details of the sheave fairlead and counterweight of a gravity-type variable-length constant-tension subsea single-point mooring connection device. [Figure 9] FIG. 1 is a three-dimensional schematic diagram showing the connection between a gravity type variable length constant tension subsea single point mooring connection device and a floating wind turbine platform at a pier shore. [Figure 10] FIG. 1 is a side view of a gravity type variable length constant tension subsea single point mooring connection device and floating wind turbine platform as the whole is towed offshore. [Figure 11] FIG. 1 is a three-dimensional schematic diagram of the lowering and installation of a subsea single-point gravity anchor of a gravity-type variable-length constant-tension subsea single-point mooring connection device. [Figure 12] FIG. 1 is a three-dimensional schematic diagram of the lowering and installation of the counterweight of a gravity variable length constant tension subsea single point mooring connection device. DETAILED DESCRIPTION OF THE INVENTION

[0022] (Example 1) As shown in Figures 1 to 3, this embodiment relates to a gravity variable length non-constant tension seabed single point mooring connection device, which includes a mooring connection device 1, a float 2, a plurality of fairleads 30, a plurality of mooring lines 32, a large counterweight 34 and attached mooring connectors 34A, a seabed single point anchor 38 disposed on the seabed 201 and attached rotary single point mooring connection device 36. Each fairlead 30 is connected to one float mooring point 31 of the float lower hull 2B, and each mooring line 32 is connected to a corresponding The mooring passes through a fairlead 30 connected to a counterweight 34 at one end and to a rotary single-point mooring connection device 36 located on top of a single-point anchor 38 on the seabed.

[0023] The floating upper hull 2A is located above the water surface 101, and the floating lower hull 2B is located below the water surface 101. A wind durbin tower 4 is provided on the floating upper hull 2A, and the wind durbin tower 4 is used to support a wind turbine nacelle 6 located on top and wind turbine blades 8 connected to the wind turbine nacelle 6.

[0024] When the float 2 is in its initial equilibrium position, the seabed single-point anchor 38 is located at the geometric center of the mooring connection device 1 on the seabed, i.e., the intersection point of the vertical centerline of the float 2 and the seabed 201, the multiple fairleads 30 and the corresponding multiple mooring lines 32 are arranged geometrically symmetrically to the corresponding float mooring points 31 on the float 2, and the counterweight 34 is arranged vertically above the seabed single-point anchor 38 and at a certain distance below the float lower hull 2B. The sum of the vertical components of the tensions in all the mooring lines 32 is equal to the weight of the counterweight 34. Due to the symmetrical arrangement, the initial tensions in each mooring line 32 are equal.

[0025] When the float 2 moves horizontally to the right due to the action of external wind load 301 and wave load 302, the effective lengths of the mooring lines 32L and 32R, i.e., the lengths of the mooring lines between the float mooring point 31 and the single-point anchor 38 on the seabed, change in accordance with the change in horizontal movement of the float 2, shortening 32L and lengthening 32R. At the same time, the counterweight 34 and the attached mooring connector 34A are connected to the mooring lines 32L and 32R and move up and down and left and right to keep the physical total lengths of the mooring lines 32L and 32R from the counterweight 34 to the single-point anchor 38 unchanged. At this time, the horizontal angles between the mooring lines 32L and 32R and the float mooring point 31 change, and the tensions in the mooring lines 32L and 32R become unequal. The sum of the vertical components of the tensions in the mooring lines 32L and 32R is equal to the weight of the counterweight 34. The horizontal component of the tension in the mooring line 32L decreases, while the horizontal component of the tension in the mooring line 32R increases. The resultant horizontal force value of the tension in all of the mooring lines 32L and 32R of the mooring connection device 1 is greater than zero and directed to the left, generating a restoring force 401 for the mooring system. Its direction is opposite to that of the external wind load 301 and the wave load 302, and their absolute values ​​are equal, so dynamic balance is achieved for the horizontal displacement of the float 2. The restoring force 401 increases as the horizontal displacement of the float 2 increases, and its magnitude can be calculated based on the internal tension values ​​of the mooring lines 32L and 32R, the water depth, and the horizontal displacement of the float. The initial internal tension of the mooring lines 32L and 32R is determined by the weight of the counterweight 34 and its position in the water.

[0026] The seabed single-point anchor 38 is provided with a rotating single-point mooring connection device 36 with a wind vane function, which allows the floater 2 to rotate in the direction of external forces 301, 302 and the wind durbin systems 6 and 8 above it to always face the direction of external forces 301, 302. This wind vane function can significantly improve the power generation efficiency of the wind durbins. When the external forces are removed, the mooring system's restoring force 401 returns the floater 2 to its original position.

[0027] The subsea single point anchor 38 is preferably a concrete gravity anchor with a vertical watertight cruciform bulkhead inside. The rotary single point mooring connection device 36 is located in the center of the vertical watertight cruciform bulkhead and has a bearing rotary device inside. The concrete gravity anchor has a skirt at the bottom that sinks below the surface of the seabed mud under the action of gravity and provides horizontal resistance.

[0028] As shown in Figure 3, when the float 2 has three fairleads 30 and three corresponding float mooring points 31, three mooring lines 32 are used, each passing through a corresponding fairlead 30, with one end connected to a counterweight 34 and the other end connected to a rotary single-point mooring connection device 36 located above a subsea single-point anchor 38.

[0029] When the float 2 is in its initial equilibrium position, the seabed single-point anchor 38 is located at the geometric center of the mooring connection device 1 on the seabed, i.e., the intersection point of the vertical centerline of the float 2 and the seabed 201. Three fairleads 30 are arranged geometrically symmetrically on the float 2. The counterweight 34 is arranged vertically above the seabed single-point anchor 38 and at a certain distance below the float 2. In this symmetrical arrangement, the initial tension of each mooring line 32 is equal, and the sum of the vertical components of the tension of all the mooring lines 32 is equal to the weight of the counterweight 34.

[0030] The mooring lines 32 are steel cables, steel chains, polyester cables or nylon cables, or a combination thereof.

[0031] The counterweight 34 is made of concrete, steel, other heavy materials, or a combination thereof. Its interior has multiple chambers, allowing it to be temporarily floated on the water surface. A mooring connector 34A, which includes three connecting plates, is mounted on it to connect mooring lines. The subsea single-point anchor 38 can be a suction anchor pile, a driven anchor pile, or a gravity anchor.

[0032] As shown in Figure 4, the fairlead 30 is located on the right side of the floating body lower hull 2B and includes a grooved pulley 30R, a set of vertical axis rotation mechanisms 30A, a support structure 30B, and a mooring line 32R, of which the vertical axis rotation mechanism 30A is connected to the floating body mooring point 31 via a connection structure 31A. One end of the mooring line 32R is connected to a seabed single-point anchor (not shown), and is redirected upward through the groove in the pulley 30R, with the other end connected to a mooring connector 34A. The size of the groove in the pulley 30R matches the size of the mooring line 32.

[0033] The upper end of the mooring connector 34A is simultaneously connected to the left mooring line 32L, and the lower end is connected to the upper end of the counter weight 34 via a connecting chain 34B.

[0034] As shown in Figure 5, the mooring connector 34A comprises a lower structure 42, an upper structure 44, three connecting plates 46 for connecting the corresponding mooring lines 32, and a plurality of connecting inner plates 48, and the lower structure 42 is connected to the counterweight 34 via a connecting chain 34B.

[0035] In practical applications, the weight of the counterweight 34 typically depends on the maximum external wind and wave forces. For large (e.g., 15 MW) floating offshore wind turbines, the weight range is typically 500 to 1,000 tons or more. The counterweight 34 has a significant weight (several hundred tons) and is suspended below the floating body 2, thereby increasing the stability of the floating body 2.

[0036] (Example 2) As shown in Figures 6 to 8, this embodiment relates to a gravity-type variable-length constant-tension seabed single-point mooring connection device. Specifically, as shown in Figure 6, when two counterweights and two mooring lines are used, each mooring line 52 passes through a corresponding fairlead 50, one end of which is connected vertically downward to a corresponding counterweight 54, and the other end of which is connected to a rotary single-point mooring connection device 56 located above a seabed single-point anchor 58. When the float 2 is in its initial equilibrium position, the seabed single-point anchor 58, each fairlead 50, and the corresponding mooring line 52 are geometrically symmetrically arranged with respect to the corresponding float mooring point 51 on the float 2. The counterweight 54 is vertically arranged at a certain distance below the corresponding fairlead 50. The tension of the mooring line 52 is equal to the weight of the corresponding counterweight 54.

[0037] As shown in Figure 7, when the float 2 moves horizontally to the right due to the action of external wind load 301 and wave load 302, the effective lengths of the mooring lines 52L and 52R, i.e., the length of the mooring line between the float mooring point 51 and the seabed single-point anchor 58, change in accordance with the horizontal movement of the float 2, shortening the mooring line 52L and lengthening the mooring line 52R. At the same time, the counterweight 54L moves downward and the counterweight 54R moves upward, keeping the physical overall length of each mooring line (52L and 52R) from the corresponding counterweight (54L and 54R) to the seabed single-point anchor 38 unchanged. At this time, the horizontal angles between the mooring lines 52L and 52R and the corresponding float mooring point 51 change, decreasing the horizontal component of tension in the mooring line 52L and increasing the horizontal component of tension in the mooring line 52R. The combined horizontal force value of the tensions of all mooring lines 52L, 52R of the mooring connection device 1A is greater than 0 and is directed to the left. This means that a restoring force 401 of the mooring system is generated. Its direction is opposite to that of the external wind load 301 and the wave load 302, and their absolute values ​​are equal, so that the horizontal movement of the float 2 can be kept in dynamic equilibrium. This restoring force 401 increases as the horizontal movement of the float 2 increases, and its magnitude can be calculated based on the internal tension values ​​of the mooring lines 52L, 52R, the water depth, and the horizontal movement of the floating vessel 2. The internal tension values ​​of the mooring lines 52L, 52R are constant values ​​equal to the weights of the corresponding canter weights 54L, 54R. When the external force is removed, the restoring force 401 returns the float 2 to its original position.

[0038] A rotary single-point mooring connection device 56 with a wind vane function, which includes a mooring connector with a set of vertical axis rotation mechanisms, a connection structure, and at least three connecting plates, is provided on top of the seabed single-point anchor 58 and is used to connect the mooring lines. This causes the floating body 2 to rotate in the direction of the external forces 301, 302, so that the wind durbin devices 6, 8 above it always face the direction of the external forces 301, 302. This wind vane function can significantly improve the power generation efficiency of the wind durbin.

[0039] The subsea single-point anchor 58 is preferably a concrete gravity anchor with a vertical cross-shaped watertight bulkhead inside. The rotary single-point fastening device 56 is located in the center of the vertical cross-shaped watertight bulkhead and has a bearing rotary device inside. The concrete gravity anchor has a skirt at the bottom that sinks below the surface of the seabed mud under the action of gravity, providing horizontal resistance.

[0040] 8, the fairlead 50 is located on the right side of the floating body lower hull 2B and includes a grooved pulley 50A, a set of vertical axis rotation mechanisms 50B, and a support structure 50C. The fairlead 50 is connected to the floating body mooring point 51 via a connecting structure 51A.

[0041] The mooring line includes a vertical portion 52A and an inclined portion 52B. One end of the vertical portion 52A is connected vertically downward to a corresponding counterweight 54 and is redirected upward through a groove in the sheave 50A. One end of the inclined portion 52B is connected to the vertical portion 52A in the groove in the sheave 50A, and the other end is connected to a single-point anchor (not shown) on the seabed. The groove in the sheave 50A is sized to accommodate the diameter of the mooring line.

[0042] When the floating body 2 rotates around the vertical axis, the vertical axis rotation mechanism 50B drives the pulley 50A and the mooring lines 52A and 52B to rotate integrally around the vertical axis.

[0043] When gravity-type variable-length constant-tension subsea single-point mooring connection devices are actually applied to floating wind power platforms, three counterweights, three fairleads, and three mooring lines of the same weight are typically used. The weight of the counterweights is determined by the maximum external wind and wave forces. For large (e.g., 15 MW) floating offshore wind turbines, the weight of each counterweight typically ranges from 300 to 700 tons or more. The counterweights are quite heavy (several hundred tons) and are suspended below the floating wind power platform, improving stability.

[0044] As shown in Figure 9, the subsea single-point anchor 58 is a reinforced concrete structure incorporating multiple vertical watertight bulkhead cavities. It can temporarily float on the water and is connected to an upper rotary single-point mooring connection device 56, which in turn connects the float 2, the wind durbin tower 4, the wind durbin nacelle 6, and the wind durbin blades. The fairleads 50, mooring lines 52, and canter weights 54 are integrated and connected to the pier shore to form an integrated floating wind power generation system 1B, and the mooring lines 52, canter weights 54, the subsea single-point anchor 58, and the float 2 are temporarily connected via an offshore fastening and lashing device (not shown). Specifically, the float 2 has three struts of the same weight, three fairleads 50, three mooring lines 52, and three canter weights 54.

[0045] In this embodiment, a floating body This relates to the overall system 1B of a wind turbine, which is installed offshore using the following methods and processes.

[0046] In a first step, as shown in Figure 10, a tugboat 501 tows the floating body 2, the wind dwarf tower 4, the wind turbine nacelle 6 and the wind turbine blades 8, the fairlead 50, the mooring lines 52, the canter weights 54, the subsea single point anchor 58 and the rotating single point mooring connection device 56 attached thereto to the location of the offshore wind farm.

[0047] In the second step, as shown in Figure 11, upon reaching the offshore wind field location, the offshore fastening and lashing devices of the submarine single-point anchor 58 and its corresponding mooring line 52 are released and seawater is pumped into the void. Under the action of gravity 601, the submarine single-point anchor 58 and the attached rotary single-point mooring connection device 56 sink to the seabed 201.

[0048] In the third step, as shown in Figure 12, the offshore fastening and lashing devices of the canter weights 54 and the corresponding mooring lines 52 are sequentially removed one by one. Due to the action of gravity 601, the canter weights 54 sink to a predetermined depth in the water, and the mooring lines 52 are fastened, completing the installation of the gravity-type variable-length constant-tension subsea single-point mooring connection device of the present invention.

[0049] The specific implementation described above can be locally adjusted in various ways by those skilled in the art without departing from the principles and purposes of the present invention. The scope of protection of the present invention is subject to the claims and is not limited by the specific embodiments described above. Each implementation scheme within the scope is subject to the constraints of the present invention. [Explanation of symbols]

[0050] 2 Floating body, 2A Floating body upper hull, 2B Floating body lower hull, 4 Wind turbine tower, 6 Wind turbine nacelle, 8 Wind turbine blade, 30 Fairlead, 30A Vertical axis rotation mechanism, 30B Support structure, 30R Pulley, 31 Floating body mooring point, 31A Connection structure, 31B Fairlead rotation structure, 32 Mooring line, 32L Left mooring line, 32R Right mooring line, 34 Counterweight, 34A Mooring connector, 34B Connecting chain, 36 Rotating single point mooring connection device, 38 Submarine single point anchor, 42 Mooring connector lower structure, 44 Mooring connector upper structure, 46 Mooring connector connecting plate, 48 Mooring connector connecting inner plate, 50 Fairlead, 50A Pulley, 50B Vertical axis rotation mechanism, 50C Support structure, 51 Floating mooring points, 51A Connection structure, 52 Mooring lines, 52A Vertical section of mooring lines, 52B Inclined section of mooring lines, 54 Counterweight, 56 Rotating single-point mooring connection device, 58 Subsea single-point anchor, 101 Water surface, 201 Seabed, 301 Wind loads, 302 Wave loads, 401 Restoring forces of mooring systems, 501 Tugboats, 601 Gravity.

Claims

1. A floating structure with a wind power tower attached above the water surface to support the wind power generation equipment. One large shared underwater counterweight positioned vertically below a certain distance from the center of the float; One subsea single-point anchor, A plurality of mooring lines; a plurality of fairleads connected to corresponding floating body mooring points; wherein each of the mooring lines passes through a corresponding fairlead, one end of which is connected to the lower shared underwater canter weight, and the other end of which is connected to the seabed single-point anchor, and the sum of the vertical components of the tensions of all the mooring lines is equal to the weight of the shared underwater canter weight; When the float moves horizontally, the shared underwater counterweight moves up and down and left and right, and the effective length of each mooring line, i.e., the length between the float mooring point and the seabed single-point anchor, changes in accordance with the movement of the float, generating a restoring force for the mooring system; a rotating single-point mooring connection device with a wind vane function is provided on the upper part of the subsea single-point anchor, the rotating single-point mooring connection device including a set of vertical axis rotation mechanisms so that the floating body rotates in the direction of external environmental forces, a connecting structure, and a mooring connector with at least three connecting plates used to connect the mooring lines; A gravity-type variable length non-constant tension seabed single point mooring connection device.

2. The floating body mooring point, the fairlead, and the mooring line constitute a mooring unit, and there are at least three sets of the mooring units; the floating body mooring points are symmetrically arranged; the seabed single-point anchor is located at the geometric center of the seabed of the mooring connection device, i.e., at the intersection of the vertical centerline of the floating body and the seabed; 2. The gravity-type variable-length non-constant tension submarine single-point mooring connection device according to claim 1, wherein the shared underwater counterweight is disposed vertically on the submarine single-point anchor.

3. The shared underwater counterweight is made of concrete, steel, or a combination thereof, has a plurality of empty chambers installed inside, and is capable of temporarily floating on the water surface; The mooring connector is provided on the upper portion of the shared underwater canter weight and includes at least three connecting plates used to connect the mooring lines; the subsea single-point anchor is a suction anchor pile, a driven anchor pile, or a gravity anchor; 2. The gravity-type variable-length non-constant tension subsea single-point mooring connection device according to claim 1, wherein the mooring line (mooring cable / mooring chain) is a steel cable, a steel chain, a polyester cable, a nylon cable, or a combination thereof.

4. The fairlead includes a grooved pulley, a set of the vertical axis rotation mechanism and the connecting structure, The pulleys are connected to the corresponding floating body mooring points via the connection structures; 2. A gravity-type variable-length non-constant tension submarine single-point mooring connection device as described in claim 1, characterized in that one end of the mooring line is connected to the shared underwater canter weight and is changed in direction through the groove of the pulley, and the other end is connected to the seabed single-point anchor, and the vertical axis rotation mechanism rotates around the vertical axis together with the pulley and the mooring line.

5. A floating structure with a wind power tower attached to the water surface to support the wind power generation equipment. One subsea single-point anchor, A plurality of mooring lines; a plurality of fairleads connected to the floating body mooring points; Includes multiple underwater counterweights, wherein each of the mooring lines passes through the corresponding fairlead, one end of which is connected vertically downward to the corresponding underwater canter weight and the other end of which is connected to the single-point anchor on the seabed, the underwater canter weight is disposed vertically below the corresponding fairlead, and the tension of the mooring line is equal to the weight of the underwater canter weight; When the float moves horizontally, the underwater counterweight moves up and down, and the effective length of each mooring line, i.e., the length between the float mooring point and the seabed single-point anchor, changes in accordance with the movement of the float, generating a restoring force for the mooring system; a rotating single-point mooring connection device with a wind vane function is provided on the upper part of the subsea single-point anchor, the rotating single-point mooring connection device including a set of vertical axis rotation mechanisms, a connecting structure, and a mooring connector with at least three connecting plates used to connect the mooring lines, so that the floating body rotates in the direction of external environmental forces; A gravity-type variable length constant tension seabed single point mooring connection device.

6. The floating body mooring point, the fairlead, the mooring line, and the underwater counterweight constitute a mooring unit, and there are at least three sets of the mooring unit, the floating body mooring points are symmetrically arranged; the seabed single-point anchor is located at the geometric center of the mooring connection device on the seabed, i.e., at the intersection of the vertical centerline of the floating body and the seabed; the mooring line is a steel cable, a steel chain, a polyester cable, a nylon cable, or a combination thereof; The underwater counterweight is made of reinforced concrete, steel, or a combination thereof.

6. A gravity-type variable length constant tension submarine single point mooring connection device according to claim 5.

7. The fairlead comprises a grooved pulley, a set of the vertical axis rotation mechanism and a support structure; the pulleys are connected to the corresponding floating body mooring points via the support structure; One end of the mooring line is connected vertically downward to the underwater counterweight, changes direction upward through the pulley groove, and the other end is connected to the seabed single-point anchor, and its internal tension is equal to the weight of the corresponding underwater counterweight; When the floating body rotates about the vertical axis, the vertical axis rotation mechanism rotates about the vertical axis together with the pulley and the mooring line.

6. A gravity-type variable length constant tension submarine single point mooring connection device according to claim 5.

8. An integrated installation method for gravity-type variable-length constant tension seabed single-point mooring connection devices, comprising: The seabed single point anchor is a reinforced concrete structure having a cross-shaped vertical watertight bulkhead therein, and has a plurality of empty spaces inside for temporarily floating on the water, and its upper part is connected to a rotary single point mooring connection device with a wind vane function located in the center of the cross-shaped vertical watertight bulkhead, and is integrated with the float, the wind durbin, and the mooring connection device on the shore of the pier to form an integrated floating wind durbin system as a whole, and the mooring rope, the underwater canter weight, and the seabed single point anchor are temporarily connected to the float via an offshore fastening device, The wind turbine integrated system includes a wind turbine tower, a wind turbine nacelle, and a wind turbine blade; the mooring connection device includes the fairlead, the mooring line, and the underwater canter weight; the concrete gravity anchor has a skirt at the bottom, allowing it to sink below the surface of the seabed mud under the action of gravity; 8. An integrated installation method for a gravity-type variable-length constant-tension seabed single-point mooring connection device according to any one of claims 5 to 7.

9. The integrated installation method according to claim 8, wherein the floating wind power Darbin integrated system is floated on the water and towed to the position of the offshore wind power plant by a tugboat.

10. The floating wind Durbin integrated system is installed at an offshore wind farm, First, remove the submarine single-point anchor and the corresponding offshore fastening device of the mooring rope; Seawater is poured into the empty chamber, and the subsea single point anchor and the attached rotary single point mooring connection device sink to the seabed under the action of gravity. Then, the underwater canter weights and the corresponding offshore fastening devices of the mooring lines are released one by one, and the underwater canter weights sink to a predetermined depth under the action of gravity. The integrated installation method according to claim 8, wherein the installation of the mooring connection device is completed when the mooring rope is tightened.

Images