Locking device, riser support arrangement and method of installing a connection of a riser

Abstract

The application provides a locking device, a riser support device and a riser installation connection method. The locking device comprises a fixing cylinder, a locking rod and a driving mechanism. The fixing cylinder is hollow inside and has a first internal thread on the inner periphery; the locking rod is arranged in the fixing cylinder; the axis of the locking rod is parallel to the axis of the fixing cylinder, and the two ends of the locking rod are respectively a driving end and a locking end; the outer periphery of the locking rod is provided with a first external thread matched with the first internal thread, so that the locking rod can rotate relative to the fixing cylinder; the first internal thread and the first external thread form a first screw pair, and the first screw pair can be self-locking; the driving mechanism is arranged at the end of the fixing cylinder close to the driving end and is connected with the driving end to drive the locking rod to rotate, so that the locking end can extend out of the fixing cylinder or retract into the fixing cylinder. Therefore, the locking operation can be completed by the operator on the deck, the working strength of the workers is greatly reduced, the influence of bad weather on the operation is reduced, and the operation safety and the operation efficiency are improved.

Description

Technical Field

[0001] This invention relates to the field of marine engineering technology, and in particular to a locking device, a riser support device, and a method for installing and connecting risers. Background Technology

[0002] A Floating Production Storage and Offloading (FPSO) is an integrated offshore oil, gas, and water production and processing facility that combines production, storage, and offloading. It typically forms a complete production and processing system with subsea production facilities and is a key piece of equipment for offshore oil and gas development, especially in deep water. The transmission of oil and gas, power, and signals between the subsea production facilities and the FPSO is achieved through risers (including rigid and flexible risers, umbilical cables, etc.). The riser support, serving as the suspension support point for the riser on the FPSO, must bear the gravity and wave loads on the riser while ensuring a reliable and secure connection of the cables and preventing fatigue failure. It is a critical piece of equipment for ensuring safe offshore oil and gas production using the FPSO.

[0003] Meanwhile, once deployed, FPSOs typically operate continuously for decades. During these decades, FPSOs cannot be docked for maintenance and repair, which means that riser supports and their components must also have sufficient service life and reliability. Otherwise, if they are damaged, they cannot be connected or disconnected from the riser, which will greatly affect the oil and gas production of the FPSO.

[0004] Because riser support systems are subjected to heavy loads and require extremely high equipment reliability, existing riser support devices cannot achieve remotely automated operation on the FPSO deck during riser installation or detachment. They require the assistance of divers and remotely operated vehicles (ROVs). Since FPSOs are typically deployed offshore, the window of opportunity for diving operations is short. Furthermore, the cables and equipment surrounding FPSOs are complex, and the underwater working environment for divers is harsh and demanding, increasing the risk of safety accidents and disrupting normal offshore oil and gas production. Summary of the Invention

[0005] The purpose of this invention is to provide a locking device, a riser support device, and a riser installation and connection method that can operate automatically without divers or underwater robots, in order to solve the problems in the prior art.

[0006] To solve the above-mentioned technical problems, the present invention provides a locking device, comprising:

[0007] The fixed cylinder is hollow inside and has a first internal thread on its inner circumference;

[0008] A locking rod is inserted into the fixed cylinder; the axis of the locking rod is coaxial with the fixed cylinder, and its two ends are a driving end and a locking end, respectively. The outer circumference of the locking rod is provided with a first external thread that is adapted to the first internal thread, so that the locking rod can rotate relative to the fixed cylinder; the first internal thread and the first external thread form a first helical pair, and the first helical pair is self-locking.

[0009] A driving mechanism is disposed at the end of the fixed cylinder near the driving end and is connected to the driving end to drive the locking rod to rotate, so that the locking end extends outward from the fixed cylinder or retracts into the fixed cylinder.

[0010] In one embodiment, the thread helix angle λ and the equivalent friction angle of the first helical pair are related by the following condition: λ≤ρ', where λ=arctan(S / (πd 2 )), ρ'=arctan(f / cos(α / 2)), f is the friction coefficient of the first helical pair, α is the thread profile angle, S is the lead, and d is the mean diameter of the first external thread;

[0011] The relationship between the working stroke L1 of the locking rod, the lead S1 of the first screw pair, and the rotation angle φ1 of the locking rod is as follows: L1=φ1×S1 / 360;

[0012] The thread profile of the first helical pair is a trapezoidal thread, a sawtooth thread, or a rectangular thread.

[0013] In one embodiment, the drive mechanism includes:

[0014] The shell is hollow inside; the axis of the shell is parallel to the axis of the fixed cylinder;

[0015] A drive shaft passes through the housing and extends out of the housing at both ends; the axis of the drive shaft is parallel to the axis of the housing, and the drive shaft is connected to the drive end of the locking rod.

[0016] A driving component, which is connected to the driving shaft;

[0017] The driving component can reciprocate through hydraulic differential, thereby driving the drive shaft to rotate and causing the locking rod to rotate and move axially.

[0018] In one embodiment, the drive member includes a piston ring disposed between the housing and the drive shaft, and the piston ring is capable of reciprocating along the axial direction of the drive shaft by hydraulic differential.

[0019] The inner circumference of the housing is provided with a second internal thread, and the outer circumference of the drive shaft is provided with a third external thread; the outer circumference of the piston ring is provided with a second external thread adapted to the second internal thread, and the inner circumference is provided with a third internal thread adapted to the third external thread. The second internal thread and the second external thread form a second helical pair, and the third internal thread and the third external thread form a third helical pair. The rotation directions of the second helical pair and the third helical pair are opposite.

[0020] Neither the second nor the third helical pair is self-locking.

[0021] In one embodiment, a first sealing ring is provided between the outer periphery of the piston ring and the housing, and a second sealing ring is provided between the inner periphery of the piston ring and the drive shaft. The first sealing ring and the second sealing ring are arranged at both ends of the piston ring in the axial direction, so as to divide the space of the housing on both sides of the piston ring into two independent cavities, and hydraulic oil with a pressure difference is introduced into the two cavities.

[0022] In one embodiment, the housing has a receiving groove on its inner periphery away from the end of the fixed cylinder, and the opening of the receiving groove faces the axis of the housing.

[0023] The drive shaft has a structure that is thicker in the middle and thinner at both ends. It includes a middle section, a first connecting section and a second connecting section located at both ends of the middle section. The outer diameter of the middle section is larger than the outer diameter of the first connecting section and the outer diameter of the middle section is larger than the outer diameter of the second connecting section. The second connecting section is close to the locking rod. The outer circumference of the first connecting section is provided with an external connecting thread, and a locking nut is screwed onto the external connecting thread.

[0024] A bearing is provided between the drive shaft and the housing, the bearing is located in the receiving groove, and the bearing is located between the locking nut and the intermediate section.

[0025] In one embodiment, the housing has a protrusion at the end near the fixed cylinder, the protrusion is away from the fixed cylinder, an adjusting nut is screwed to the outer periphery of the protrusion, the adjusting nut abuts against the end of the piston ring near the fixed cylinder, and an adjusting shim is provided between the bearing and the intermediate section.

[0026] In one embodiment, the rotation angle φ of the drive shaft is greater than or equal to the required rotation angle of the locking rod, and the stroke L2 of the piston ring is greater than or equal to (S2+S3)L1 / S1, wherein S1, S2 and S3 are the leads of the first helical pair, the second helical pair and the third helical pair, respectively.

[0027] In one embodiment, a gear protrudes outward from the middle of the drive shaft;

[0028] The driving component includes a cylinder disposed below the gear and a piston rod disposed inside the cylinder. The axes of the cylinder and the piston rod are both perpendicular to the axis of the driving shaft. A meshing port corresponding to the gear is opened in the middle of the cylinder. A rack that meshes with the gear is provided in the middle of the piston rod. The rack meshes with the gear through the meshing port.

[0029] In one embodiment, sealing rings are provided at both ends of the piston rod to divide the space at both ends of the cylinder into two independent cavities;

[0030] The axis of the cylinder is located on the center plane of the axial length of the gear;

[0031] The axis of the cylinder does not intersect the axis of the housing.

[0032] In one embodiment, the length L3 and stroke L4 of the piston rod are both not less than φ1z / 360, where φ1 is the rotation angle of the locking rod, z is the number of teeth of the gear, and the total length L5 of the cylinder is greater than or equal to the sum of the length L3 and stroke L4 of the piston rod.

[0033] In one embodiment, the drive shaft includes a gear shaft and a spline shaft coaxially arranged, the spline shaft is disposed at the end of the gear shaft facing the locking rod, the gear is disposed on the gear shaft, and the spline shaft is connected to the locking rod;

[0034] The piston rod is provided with adjusting screws and adjusting shims at both ends, with the adjusting shims located between the adjusting screws and the piston rod.

[0035] In one embodiment, the housing includes a cylindrical body and flanges located at both ends of the cylindrical body, the flanges being detachably connected to the cylindrical body;

[0036] Both ends of the drive shaft are provided with limiting shoulders, and the two limiting shoulders correspond one-to-one with the two flanges. Each limiting shoulder is located inside the cylinder and abuts against the inner circumference of the corresponding flange to restrict the axial sliding of the drive shaft.

[0037] The two ends of the drive shaft pass through corresponding flanges.

[0038] In one embodiment, an external spline is sleeved on the end of the drive shaft facing the locking rod, and an internal spline hole is provided on the drive end of the locking rod. The external spline is adapted to the internal spline hole, and the external spline extends into the internal spline hole. The axial sliding stroke of the external spline and the internal spline hole is greater than the working stroke of the locking rod.

[0039] In one embodiment, the locking device further includes a position monitoring sensor for detecting the position of the locking rod, the position monitoring sensor being electrically connected to a control station to transmit the position signal of the locking rod to the control station.

[0040] In one embodiment, the locking device further includes a manual drive lever;

[0041] The drive shaft has a through hole extending through its axis. The drive end of the locking rod has a slot with an opening facing the drive shaft. The manual drive rod passes through the through hole and extends into the slot, and is connected and fixed to the locking rod. The end of the manual drive rod away from the locking rod extends out of the housing.

[0042] The locking device further includes a locking screw; a boss is provided at one end of the housing away from the fixed cylinder, the manual drive rod passes through the boss, the axis of the locking screw is perpendicular to the axis of the manual drive rod, and the locking screw can pass through the boss to abut against the manual drive rod and lock the manual drive rod.

[0043] In one embodiment, the locking device further includes a control valve assembly fixed to the outside of the housing. The control valve assembly includes two hydraulic locks arranged in parallel, with each hydraulic lock corresponding to one of the two cavities inside the housing. Each hydraulic lock includes an overflow valve and a hydraulically controlled check valve arranged in parallel.

[0044] The control valve assembly also includes a shut-off valve, which is located between the hydraulic lock and the two cavities, enabling the two cavities to be isolated or connected.

[0045] The present invention also provides a riser support device, including a support member and a plurality of locking devices evenly arranged around the outer periphery of the support member in a circumferential direction. The support member is cylindrical, and the locking devices are as described above.

[0046] In one embodiment, a plurality of the locking devices are connected in parallel and connected to a remote monitoring system and a hydraulic pump station on the deck via hydraulic lines;

[0047] The riser support device also includes a reversing valve for switching the flow direction of the hydraulic oil entering the locking device;

[0048] The riser support device also includes a pressure reducing valve for adjusting the hydraulic oil pressure entering the locking device.

[0049] In one embodiment, the riser support device further includes a limiting mechanism; the limiting mechanism is provided at both the upper and lower parts of the support member;

[0050] Each of the limiting mechanisms includes a plurality of limiting members evenly arranged on the outer periphery of the support member, and the plurality of limiting members are located in the same plane;

[0051] Each of the aforementioned limiting components includes a limiting block and a hydraulic power component for driving the limiting block to move. The limiting block is inclined and forms an acute angle with the horizontal plane.

[0052] Multiple limiting blocks together abut against the riser suspension head.

[0053] The present invention also provides a method for installing and connecting a riser, wherein the method employs the riser support device described above, and the method includes the following steps:

[0054] A traction cable is lowered from the FPSO and passed through the support member.

[0055] A riser suspension head is provided, and one end of the riser suspension head is connected to the end of the riser, and the riser suspension head is connected to the traction end of the traction cable; wherein, the outer diameter of the riser suspension head is smaller than the inner diameter of the support member.

[0056] The riser suspension head is inserted into the support member from bottom to top by the traction cable, and the riser suspension head is suspended in the support member;

[0057] The locking rod of the locking device is extended and abuts against the riser suspension head to lock the riser suspension head;

[0058] The riser suspension head is connected to the ship's side pipeline to achieve the connection between the riser and the ship's side pipeline.

[0059] In one embodiment, the step of suspending the riser suspension head within the support includes:

[0060] The limiting member located on the support extends and stops the protrusion on the riser suspension head, preventing the riser suspension head from sliding down and thus suspending the riser suspension head.

[0061] As can be seen from the above technical solution, the advantages and positive effects of the present invention are as follows:

[0062] The locking device of this invention uses a drive mechanism to extend or retract the locking rod relative to the fixed cylinder, achieving locking and unlocking functions. This locking device eliminates the need for divers to descend into the water or underwater robots to perform underwater operations; operators can complete the locking work from the deck, significantly reducing worker workload and the impact of inclement weather, while improving operational safety and efficiency. Furthermore, the locking device provides a reliable locking function through the friction between the fixed cylinder and the locking rod, utilizing the mechanical locking function of the fixed cylinder and the locking rod, and locking in one step without manual intervention, greatly improving convenience.

[0063] The riser support device achieves the locking or unlocking of the riser suspension head through the cooperation of multiple locking devices arranged in parallel, thereby achieving the locking or unlocking of the riser.

[0064] The riser installation and connection method in this invention uses a riser support device, allowing the locking operation to be completed on the deck, greatly reducing the labor intensity of workers and the impact of inclement weather on the operation, and improving operational safety and efficiency. Furthermore, the entire installation and connection method only requires launching into the water for the final connection between the riser suspension head and the ship's side pipeline, and this operation requires no load; only the connection itself is needed, making the operation simple. Attached Figure Description

[0065] Figure 1 This is a schematic diagram of the FPSO and riser in this invention.

[0066] Figure 2 This is a front view schematic diagram of one embodiment of the riser support device in this invention.

[0067] Figure 3 yes Figure 2 The sectional view in the image.

[0068] Figure 4 This is a cross-sectional view of the first embodiment of the locking device in this invention.

[0069] Figure 5 This is a cross-sectional view from another perspective of the first embodiment of the locking device in this invention.

[0070] Figure 6 This is a schematic diagram of the control valve assembly of the first embodiment of the locking device in this invention.

[0071] Figure 7 This is a schematic cross-sectional view of the second embodiment of the locking device in this invention, wherein the locking rod is retracted into the fixed cylinder.

[0072] Figure 8 This is a schematic cross-sectional view of the second embodiment of the locking device in this invention, wherein the locking rod extends out of the fixing cylinder.

[0073] Figure 9 This is a schematic diagram of a cross-sectional view from another perspective of the second embodiment of the locking device in this invention, wherein the locking rod is retracted into the fixed cylinder.

[0074] Figure 10 This is a schematic diagram of a cross-sectional view from another perspective of the second embodiment of the locking device in this invention, wherein the locking rod extends out of the fixing cylinder.

[0075] Figure 11 This is a schematic diagram of the control valve assembly of the second embodiment of the locking device in this invention.

[0076] Figure 12 This is a schematic diagram of the hydraulic principle of the riser support device in this invention.

[0077] The annotations in the attached figures are explained as follows:

[0078] 10. Hull; 20. Riser support device; 30. Side pipeline; 40. Riser; 50. Riser suspension head;

[0079] 6. Support components;

[0080] 7. Locking device; 71. Fixed cylinder; 72. Locking rod; 73. Fixed pressure block; 741. Housing; 7411. First oil port; 7412. Second oil port; 7413. Boss; 742. Drive shaft; 743. Drive component; 751. Locking nut; 752. Bearing; 753. External spline; 761. First sealing ring; 762. Second sealing ring; 763. Third sealing ring; 764. Fourth sealing ring; 771. Overflow valve; 772. Hydraulic check valve; 773. Shut-off valve; 776. Adjusting nut; 777. Adjusting shim; 78. Manual drive rod; 791. Locking screw; 793. Position monitor;

[0081] 8. Locking device; 81. Fixed cylinder; 82. Locking rod; 83. Fixed pressure block; 841. Housing; 8411. Oil filling / draining screw; 842. Drive shaft; 8421. Gear; 843. Cylinder; 8431. First oil port; 8432. Second oil port; 844. Piston rod; 845. Sealing ring; 876. Adjusting screw; 877. Adjusting shim; 88. Manual drive rod; 891. Locking screw; 893. Position monitor;

[0082] 91. Limiting element; 92. Pressure reducing valve; 93. Directional control valve. Detailed Implementation

[0083] Although the invention can be readily embodied in various forms, only some specific embodiments are shown in the accompanying drawings and will be described in detail in this specification. It is understood that this specification should be regarded as an exemplary illustration of the principles of the invention and is not intended to limit the invention to what is described herein.

[0084] Therefore, a feature pointed out in this specification is used to illustrate one feature of one embodiment of the invention, and does not imply that every embodiment of the invention must have the described feature. Furthermore, it should be noted that this specification describes many features. While certain features may be combined to illustrate possible system designs, these features may also be used in other combinations not explicitly stated. Therefore, unless otherwise stated, the described combinations are not intended to be limiting.

[0085] In the embodiments shown in the accompanying drawings, the directional indications (such as up, down, left, right, front, and back) used to explain the structure and movement of the various elements of the invention are relative rather than absolute. These descriptions are appropriate when these elements are in the positions shown in the drawings. If the descriptions of the positions of these elements change, these directional indications also change accordingly.

[0086] The preferred embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0087] Figure 1 A schematic diagram of the FPSO and riser is shown; please refer to [reference needed]. Figure 1 An FPSO comprises a hull 10, a riser support device 20 located on the outer side of the hull 10 near its bottom, and a shipside pipeline 30 located on the outer side of the hull 10. The riser 40 originates from an oil well in the subsea production system and is suspended on the outer side of the hull 10 via the riser support device 20. A processing module is located on the deck of the hull 10. This module separates carbon dioxide from the crude oil. The carbon dioxide passes through the shipside pipeline 30 into the riser 40 and is then transported to the subsea wellhead, where it is injected into the underground oil reservoir to drive oil production, increasing oil recovery while also partially sequestering carbon dioxide.

[0088] The riser 40 is connected to the shipside pipeline 30 via a riser suspension head 50, which is supported on the outside of the hull 10 by a riser support device 20. The riser suspension head 50 is a tubular structure that matches the riser support device 20, with its two ends connected to the riser 40 and the shipside pipeline 30, respectively. By designing corresponding riser suspension heads 50 for different risers 40, a single riser support device 20 can be used to fix and connect rigid risers, flexible risers, and even umbilical cables.

[0089] The present invention provides a riser support device 20, which eliminates the need for divers to dive and underwater robots to carry out load-bearing operations during the installation, connection and disconnection of the riser 40. Operators can basically complete the work on the deck, which greatly reduces the labor intensity of workers and the impact of bad weather on the work, and improves the safety and efficiency of the work.

[0090] Figure 2 A front view schematic diagram of one embodiment of the riser support device 20 is shown. Figure 3 It shows Figure 2 See the sectional view in the middle. Figure 2 and Figure 3 The riser support device 20 includes a support member 6 and a plurality of locking devices evenly arranged along the circumference of the support member 6.

[0091] The support member 6 is fixed to the side of the hull 10 in the vertical direction and to the extended structure near the bottom of the hull 10. In this embodiment, the support member 6 is inclined, and the angle between its axis and the horizontal plane is less than or equal to 10° to adapt to the inclination direction of the riser 40.

[0092] Specifically, the support member 6 is cylindrical and open at both ends. The support member 6 is used to allow the riser suspension head 50 to pass through, so that multiple locking devices work together to lock the riser suspension head 50.

[0093] The following description uses the example of multiple locking devices located in the same plane on the outer periphery of the support member 6. In other embodiments, multiple locking devices located in two or more planes at different heights can also be provided on the outer periphery of the support member 6, forming a multi-layer arrangement, with each layer including multiple locking devices evenly arranged circumferentially.

[0094] The support member 6 has multiple mounting holes along its circumference, and the axes of the mounting holes are perpendicular to the axis of the support member 6. That is, the axes of the mounting holes extend radially along the support member 6. The mounting holes are used for the passage and installation of locking devices.

[0095] Preferably, the number of locking devices is even, meaning the locking devices are arranged in pairs. Correspondingly, the number of mounting holes is also even. In this embodiment, a riser support device 20 includes eight locking devices. In other embodiments, the number of locking devices can be set according to actual needs.

[0096] The locking device is located in the middle of the axial length of the support member 6.

[0097] Multiple locking devices are evenly arranged circumferentially and abut against the riser suspension head 50 located in the support member 6 from multiple directions, thereby locking the riser suspension head 50.

[0098] The locking device of this application is described below through different embodiments.

[0099] First embodiment of locking device

[0100] Figure 4 A cross-sectional view of the locking device 7 is shown. Figure 5 A cross-sectional view of the locking device 7 from another direction is shown. (See reference) Figure 4 and Figure 5 The locking device 7 includes a fixed cylinder 71, a locking rod 72, and a drive mechanism. The drive mechanism drives the locking rod 72 to extend or retract relative to the support member 6 to lock the riser suspension head 50.

[0101] The fixing cylinder 71 is fixed to the outer periphery of the support member 6. The fixing cylinder 71 and the support member 6 are connected by a fixing block 73. Specifically, the fixing cylinder 71 has a groove around its outer periphery near the support member 6, the opening of which is opposite to the axis of the fixing cylinder 71. This groove is located outside the support member 6. The fixing block 73 is engaged within the groove. The fixing cylinder 71 is inserted into the mounting hole of the support member 6, and the fixing block 73 and the support member 6 are connected by screws, thereby achieving the connection between the fixing cylinder 71 and the support member 6.

[0102] In this embodiment, the inner end of the fixing cylinder 71 is flush with the inner peripheral wall of the support member 6. Here, "inner" refers to the direction towards the axis of the support member 6, and "outer" refers to the opposite direction.

[0103] The fixed cylinder 71 is hollow inside and open at both ends. The inner circumference of the fixed cylinder 71 is provided with a first internal thread.

[0104] The locking rod 72 passes through the fixed cylinder 71, and the axis of the locking rod 72 is coaxial with the fixed cylinder 71, that is, the axis of the locking rod 72 and the axis of the fixed cylinder 71 are on the same straight line.

[0105] The locking rod 72 has a driving end and a locking end at its two ends, respectively. The locking end is closer to the support member 6, while the driving end is farther away from the support member 6. That is, the locking end is used to contact the riser suspension head 50 to achieve locking, and the driving end is used to connect with the driving mechanism to achieve rotation of the locking rod 72.

[0106] The locking rod 72 has a first external thread on its outer periphery that matches the first internal thread, allowing the locking rod 72 to rotate relative to the fixed cylinder 71, thereby enabling the locking end to extend outward from the fixed cylinder 71 or retract into the fixed cylinder 71. The locking end extends out of the fixed cylinder 71 and can abut against the riser suspension head 50. The locking rods 72 of multiple locking devices 7 abut against the riser suspension head 50 together to achieve locking.

[0107] The first internal thread and the first external thread constitute a first helical pair, and the first helical pair is self-locking. Specifically, the relationship between the thread helix angle λ and the equivalent friction angle of the first helical pair satisfies: λ≤ρ', where λ=arctan(S / (πd 2)), ρ'=arctan(f / cos(α / 2)), where f is the friction coefficient, α is the thread profile angle, S is the lead, and d is the pitch diameter of the external thread.

[0108] Typically, the thread helix angle λ is no greater than 4°30′. The effective number of engagement turns of the first internal thread and the first external thread of the first helical pair is no less than 6 turns.

[0109] Furthermore, the relationship between the working stroke L1 of the locking rod 72, the lead S1 of the first screw pair, and the rotation angle φ1 of the locking rod 72 is as follows: L1 = φ1 × S1 / 360. That is, the minimum rotation angle φ1 required to drive the locking rod 72 to rotate is 360 × L1 / S1 degrees.

[0110] During the locking operation of the first helical pair, the locking rod 72 rotates relative to the fixed cylinder 71, causing the locking end to approach the riser suspension head 50. Before the locking end of the locking rod 72 contacts the riser suspension head 50, only a small torque is needed to overcome the friction of the first helical pair, allowing the locking end of the locking rod 72 to extend out of the fixed cylinder 71. After the locking end contacts the riser suspension head 50 and the resulting resistance is greater than or equal to the driving torque, the locking rod 72 automatically stops rotating and extending, achieving the locking state. At this time, due to the self-locking characteristic of the first helical pair, even if the driving force is turned off, the locking rod 72 can maintain the locking state continuously, and the locking state will not change regardless of how the load transmitted from the riser 40 to the locking rod 72 changes. When unlocking is required, it is only necessary to reverse the rotation of the locking rod 72 to move the locking end of the locking rod 72 away from the riser suspension head 50, that is, the locking end retracts. Meanwhile, the first internal thread ring is located on the inner circumference of the fixed cylinder 71, and the first external thread ring is located on the outer circumference of the locking rod 72, so that the first helical pair is a continuous helical surface contact pair. Therefore, the locking rod 72 can stop at any position within the designed stroke, and can achieve reliable self-locking at any position.

[0111] The drive mechanism is located at the end of the fixed cylinder 71 near the drive end and is connected to the drive end to drive the locking rod 72 to rotate, thereby causing the locking end to extend out of the fixed cylinder 71 or retract into the fixed cylinder 71.

[0112] Specifically, the drive mechanism includes a housing 741, a drive shaft 742, and a drive element 743.

[0113] The housing 741 is hollow inside, and its axis is parallel to the axis of the fixed cylinder 71. Specifically, the housing 741 includes a cylinder and flanges located at both ends of the cylinder. The cylinder and flanges are detachably connected, making installation and disassembly convenient. Preferably, the housing 741 is coaxial with the locking rod 72.

[0114] The drive shaft 742 passes through the housing 741, with both ends of the drive shaft 742 extending out of the housing 741. Specifically, both flanges have through holes through which the drive shaft 742 passes and extends out of the housing 741. The axis of the drive shaft 742 is parallel to the axis of the housing 741.

[0115] The drive shaft 742 includes an intermediate section along the axial direction, and a first connecting section and a second connecting section located at both ends of the intermediate section. The outer diameter of the intermediate section is larger than the outer diameter of the first connecting section, and the outer diameter of the intermediate section is larger than the outer diameter of the second connecting section. The second connecting section is close to the locking rod 72. That is, the drive shaft 742 has a structure that is thicker in the middle and thinner at both ends.

[0116] The drive shaft 742 also includes a first protruding section and a second protruding section extending out of the housing 741. The first protruding section is connected to the first connecting section, and the second protruding section is connected to the second connecting section, with the second protruding section extending into the fixed cylinder 71. In this embodiment, the second protruding section has an arc transition near the housing 741, that is, the second protruding section and the second connecting section have an arc transition.

[0117] The drive shaft 742 rotates within the housing 741 and cannot slide along the axial direction of the housing 741. Specifically, the drive shaft 742 and the housing 741 are connected by a locking nut 751 and a bearing 752, thereby constraining the drive shaft 742 to rotate within the housing 741 and preventing the drive shaft 742 from sliding along the axial direction.

[0118] A receiving groove is provided on the inner circumference of the housing 741 at the end away from the fixed cylinder 71, and the opening of the receiving groove faces the axis of the housing 741. Specifically, the cylinder has a stepped structure at this end, and the flange and the stepped structure together form the receiving groove. The outer circumference of the first connecting section is provided with an external connecting thread, and a locking nut 751 is screwed onto the external connecting thread. A bearing 752 is provided between the drive shaft 742 and the housing 741. The bearing 752 is located in the receiving groove and between the locking nut 751 and the intermediate section. The bearing 752 can be a four-point contact ball bearing 752, a double-direction thrust ball bearing 752, or a combination of two thrust bearings 752 capable of withstanding bidirectional axial loads. For example, a four-point contact ball bearing 752 of model QJ318.

[0119] The drive shaft 742 is connected to the drive end of the locking rod 72, thereby driving the locking rod 72 to rotate. Specifically, an external spline 753 is sleeved on the end of the drive shaft 742 facing the locking rod 72, and an internal spline hole is provided on the drive end of the locking rod 72. The external spline 753 is adapted to the internal spline hole and extends into the internal spline hole of the locking rod 72, forming a sliding spline pair that can both transmit torque and slide along the axis. That is, the drive shaft 742 and the locking rod 72 are connected through the sliding spline pair. The spline shape of this sliding spline pair can be a rectangular spline or an involute spline. In this embodiment, the spline shape of the sliding spline pair is an 8-tooth rectangular spline.

[0120] The axial sliding stroke of the external spline 753 and the internal spline hole is greater than the working stroke L1 of the locking rod 72. Therefore, the rotation of the drive shaft 742 can be transmitted to the locking rod 72 through the spline shaft, and the two rotate synchronously. Furthermore, the existence of the sliding spline pair allows the locking rod 72 to freely extend and retract axially.

[0121] The drive component 743 is connected to the drive shaft 742. The drive component 743 can reciprocate through hydraulic differential, thereby driving the drive shaft 742 to rotate, and causing the locking rod 72 to rotate and move axially.

[0122] The drive unit 743 includes a piston ring disposed between the housing 741 and the drive shaft 742, and the piston ring is capable of reciprocating along the axial direction of the drive shaft 742 by means of hydraulic differential.

[0123] A first sealing ring 761 is provided between the outer circumference of the piston ring and the housing 741, and a second sealing ring 762 is provided between the inner circumference of the piston ring and the drive shaft 742. The first sealing ring 761 and the second sealing ring 762 are located at opposite ends of the piston ring along its axial direction, dividing the space of the housing 741 on both sides of the piston ring into two independent cavities. A third sealing ring 763 and a fourth sealing ring 764 are respectively provided at both ends inside the housing 741. The third sealing ring 763 is located between the flange away from the fixed cylinder 71 and the outer circumference of the drive shaft 742, and the fourth sealing ring 764 is located between the housing 741 and the flange, close to the fixed cylinder 71. The first sealing ring 761 and the second sealing ring 762 ensure the independence between the two cavities, that is, the two cavities are not connected to each other. The third sealing ring 763 and the fourth sealing ring 764 ensure that the hydraulic oil inside the housing 741 will not leak into the seawater.

[0124] Hydraulic oil with a pressure difference is introduced into the cavities on both sides of the piston ring, which drives the piston ring to reciprocate axially within the housing 741. Specifically, one cavity has a first oil port 7411, and the other cavity has a second oil port 7412. During operation, one of them receives oil, while the other receives oil. For example, if the cavity closer to the fixed cylinder 71 receives oil and the cavity farther from the fixed cylinder 71 receives oil, the locking rod 72 can be pushed to rotate clockwise and extend out of the fixed cylinder 71; conversely, rotating counterclockwise will cause the locking rod 72 to rotate counterclockwise and retract into the fixed cylinder 71.

[0125] Specifically, the inner circumference of the housing 741 is provided with a second internal thread, and the outer circumference of the drive shaft 742 is provided with a third external thread. The outer circumference of the piston ring is provided with a second external thread adapted to the second internal thread, and the inner circumference is provided with a third internal thread adapted to the third external thread. The second internal thread and the second external thread form a second helical pair, and the third internal thread and the third external thread form a third helical pair. The rotation directions of the second helical pair and the third helical pair are opposite. Neither the second helical pair nor the third helical pair is self-locking, that is, the thread helix angle λ of the second helical pair and the third helical pair is greater than the equivalent friction angle ρ'.

[0126] The tooth profiles of both the second and third helical pairs can be trapezoidal, triangular, rectangular, or involute helical. The length of the second internal thread is less than the length of the second external thread, and the length of the third internal thread is less than the length of the third external thread.

[0127] After the piston ring moves axially along the drive shaft 742 for a stroke L2, the second and third helical pairs will rotate by angles φ2 and φ3 respectively. Since the second and third helical pairs rotate in opposite directions, the angle of rotation of the drive shaft 742 relative to the housing 741 is φ4 = φ2 + φ3 = 360 × L2 / (S2 + S3), where S2 and S3 are the leads of the second and third helical pairs respectively.

[0128] The rotation angle of the drive shaft 742 should be greater than or equal to the required rotation angle of the locking rod 72, i.e., φ4≥φ1. Correspondingly, the piston ring stroke L2 should satisfy: L2≥(S2+S3)L1 / S1.

[0129] The locking device achieves locking or unlocking functions in automatic mode through the cooperation of the first screw pair, the second screw pair, and the third screw pair.

[0130] For example, the working stroke of the locking rod 72 is 16mm, corresponding to a rotation angle of 320°. The maximum load capacity of the locking rod 72 is 3000kN. The first helical pair adopts a 30° trapezoidal section thread with good centering performance, a nominal thread diameter of 180mm, a pitch P = 18mm, a single-start right-hand thread, a thread lead S = P = 18mm, and a thread helix angle of 1.92°. Both the fixed cylinder 71 and the locking rod 72 are made of 316L stainless steel. When the friction coefficient f is 0.5, the corresponding equivalent friction angle is 2.96°, which meets the self-locking condition. The main parameters of the second helical pair are as follows: nominal diameter 140mm, left-hand thread, 8 overlapping turns of internal and external threads, a pitch of 6mm, 16 starts, and a corresponding thread helix angle of 12.6°. The main parameters of the third helical pair are as follows: nominal diameter 110mm, right-hand thread, 12 overlapping turns of internal and external threads, pitch 4mm, 24 threads, and a corresponding thread helix angle of 15.8°. The maximum stroke space of the piston ring is 48mm, corresponding to a maximum rotation angle of 360° for the drive shaft 742, which is 40° larger than the rotation angle required by the locking rod 72.

[0131] The locking device 7 also includes a control valve assembly for control and to ensure safety. The control valve assembly is fixed to the outside of the housing 741. Figure 6 A schematic diagram of the control valve assembly is shown; see reference. Figure 6 The control valve assembly includes two hydraulic locks arranged in parallel, each corresponding to one of the two cavities of the housing 741. Each hydraulic lock is connected in series with its corresponding cavity. Each hydraulic lock includes a relief valve 771 and a hydraulically controlled check valve 772 arranged in parallel. The two hydraulic locks are connected to the first oil port 7411 and the second oil port 7412 of the housing 741 via stainless steel pipes. Hydraulic oil enters the cavity corresponding to one hydraulic lock through that lock, then pushes the piston rod to move, causing the hydraulic oil to flow out from the other cavity through the other hydraulic lock. The hydraulic locks are used to prevent overpressure within the cavities from damaging the equipment and to prevent hydraulic pipeline rupture from endangering operational safety.

[0132] The control valve assembly also includes a shut-off valve 773. The shut-off valve 773 is located between the cavity and the hydraulic lock, enabling the two cavities to be isolated or connected. It can be understood that the shut-off valve 773 is connected in parallel with the housing 741. When the shut-off valve 773 is in the closed state, the hydraulic lock forms a passage with the corresponding cavity; at this time, the two cavities are isolated and not connected. When the shut-off valve 773 is in the open state, the two cavities of the housing 741 and the shut-off valve 773 form a passage; at this time, the two cavities are connected via the hydraulic lock and the shut-off valve 773.

[0133] During normal operation, the shut-off valve 773 is closed. The hydraulic lock is only opened and a passage is formed when the oil supply pressure exceeds the opening pressure of the hydraulically controlled check valve 772, thus initiating hydraulic drive action and ensuring the normal and safe operation of the locking device 7. Simultaneously, when the hydraulic power station is off, the drive shaft 742 remains stationary to prevent loosening of the locking rod 72 due to potential vibrations from external loads. In the event of a malfunction in the hydraulic system or automatic control system, the shut-off valve 773 opens, allowing free communication between the two chambers. Divers or underwater robots can manually rotate the locking rod 72 in manual mode to achieve manual locking or unlocking.

[0134] In this embodiment, the overflow valve 771, the hydraulic check valve 772, and the shut-off valve 773 are embedded in a valve body to form a control valve group. That is, the overflow valve 771, the hydraulic check valve 772, and the shut-off valve 773 are all cartridge valves to minimize the volume of the control valve group.

[0135] The working principle of locking device 7 is as follows:

[0136] Hydraulic oil with a pressure difference is injected into the two chambers of the housing 741, causing the piston rod to move and rotate along the axial direction of the housing 741. This rotation drives the drive shaft 742 to rotate, which in turn drives the locking rod 72 to rotate, causing the locking rod 72 to extend or retract axially. The extension and retraction of the locking rod 72 are achieved by controlling the pressure difference between the two chambers.

[0137] Furthermore, the housing 741 has a protrusion at the end near the fixed cylinder 71, the protrusion facing away from the fixed cylinder 71. Specifically, the protrusion is located on the flange near the fixed cylinder 71. An adjusting nut 776 is screwed onto the outer periphery of the protrusion, and the adjusting nut 776 abuts against the end of the piston ring near the fixed cylinder 71. An adjusting shim 777 is provided between the bearing 752 and the intermediate section. By changing the thickness of the adjusting shim 777, the extension length of the adjusting nut 776 can be adjusted, thereby adjusting the stroke range of the piston ring within the housing 741, thus changing the starting and ending rotation angle position and range of the drive shaft 742, ultimately achieving the purpose of adjusting the stroke of the locking rod 72, and eliminating the influence of machining tolerances and assembly errors. Specifically, in this embodiment, the adjustment amount of the adjusting shim 777 and the adjusting nut 776 is the same, for example, both are -2.7mm to 2.7mm, corresponding to a stroke adjustment range of -1mm to 1mm for the locking rod 72.

[0138] Furthermore, the locking device 7 also includes a manual drive rod 78. The manual drive rod 78 passes through the housing 741 from the end of the housing 741 away from the fixed cylinder 71 and extends into the fixed cylinder 71 to connect with the locking rod 72. The manual drive rod 78 can be rotated by a diver or underwater robot to rotate the locking rod 72 to extend or retract, thereby realizing the locking or unlocking function of the triple helix locking device 7 in manual mode. This ensures that even if the hydraulic drive of the drive component 743 or other systems fail, the locking device 7 can still lock the riser 40 or release the lock.

[0139] That is, when the shut-off valve 773 is open, the locking rod 72 is extended or retracted by rotating the manual drive rod 78, thereby achieving manual locking or unlocking.

[0140] Specifically, a through hole extending axially is formed on the drive shaft 742. The driving end of the locking rod 72 has a slot with an opening facing the drive shaft 742. A manual drive rod 78 passes through the drive shaft 742, extends into the slot, and is connected and fixed to the locking rod 72, with the end of the manual drive rod 78 extending out of the housing 741 away from the locking rod 72. Specifically, the manual drive rod 78 and the locking rod 72 are connected and fixed using a flat key or spline. In this embodiment, the manual drive rod 78 and the locking rod 72 are connected by a pair of 18x7 flat keys.

[0141] The manual drive lever 78 includes a prism portion and a cylindrical portion. The prism portion extends out of the housing 741 away from the fixed cylinder 71, and the cylindrical portion passes through the housing 741 and extends into the locking lever 72. The cross-section of the prism portion can be square or regular hexagonal, and the manual drive lever 78 can be rotated by clamping the prism portion with a wrench.

[0142] The locking device 7 also includes a locking screw 791 for locking the manual drive lever 78. Specifically, a boss 7413 is provided at the end of the housing 741 away from the fixed cylinder 71, through which the manual drive lever 78 passes. The boss 7413 can be integrally formed with the flange, or the boss 7413 can be welded to the outside of the flange.

[0143] The axis of the locking screw 791 is perpendicular to the axis of the manual drive rod 78. The locking screw 791 can pass through the boss 7413 and abut against the manual drive rod 78 to lock the manual drive rod 78. When the locking device 7 is working normally, the locking screw 791 is in an untightened state, and the manual drive rod 78 can rotate and extend freely with the locking rod 72. When the locking device 7 malfunctions, the manual drive rod 78 can be pressed by tightening the locking screw 791, thereby locking the manual drive rod 78 and ensuring that the locking rod 72 can maintain the required locking or unlocking state. This can prevent the locking rod 72 from loosening due to vibrations from external loads, ensuring the safe operation of the equipment.

[0144] The locking device 7 also includes a position monitor 793 for monitoring the position of the locking lever 72. The position monitor 793 transmits the monitored position signal of the locking lever 72 to the control station on the hull 10 for feedback to the operator. In this embodiment, the position monitor 793 uses a magnetic proximity switch, which is located at the end of the fixed cylinder 71 near the housing 741. The driving end of the locking lever 72 is equipped with a permanent magnet, and the extension length of the locking lever 72 is monitored by detecting the permanent magnet. The position monitor 793 is electrically connected to the control station via a cable.

[0145] In this embodiment, the locking device 7 extends or retracts the locking rod 72 relative to the fixed cylinder 71 through a drive mechanism, achieving locking and unlocking functions. This eliminates the need for divers to descend into the water or underwater robots to perform underwater operations; operators can complete the locking work from the deck, significantly reducing worker workload and the impact of inclement weather, while improving safety and efficiency. Furthermore, the locking device 7 provides a reliable locking function solely through the friction between the fixed cylinder 71 and the locking rod 72, requiring no energy consumption.

[0146] The locking device 7 can adjust the stroke of the locking rod 72 within a small range by adjusting the shim 777 and the adjusting nut 776, thereby eliminating the influence of machining and installation errors.

[0147] The locking device 7 achieves dual locking assurance through the self-locking of the fixed cylinder 71 and the locking rod 72, while also adding a hydraulic lock to the control valve group, greatly improving the reliability of locking.

[0148] The entire locking device 7 is small in size and compact in structure, making it convenient for multiple locking devices 7 to be used in combination flexibly. Moreover, the locking device 7 has a high load-bearing capacity, which is a significant advantage in resisting large external loads.

[0149] While the locking device 7 is hydraulically driven, it also retains the manual drive lever 78, realizing that the automatic and manual working modes do not interfere with each other, improving the overall reliability of the equipment, and avoiding the loss of oil and gas production caused by the locking device 7 being placed underwater for a long time (5 to 20 years) and failing.

[0150] The locking device 7 in this embodiment can be used not only to lock the riser 40, but also individually or in combination for other applications. For example, it can be used as a jack to lift heavy objects or as a leveling support device to adjust objects.

[0151] Second embodiment of locking device

[0152] Combination Figures 7-10 The locking device 8 in this embodiment also includes a fixed cylinder 81, a locking rod 82 and a driving mechanism, wherein the structures of the fixed cylinder 81 and the locking rod 82 are the same as those in the first embodiment.

[0153] The drive mechanism in this embodiment also includes a housing 841, a drive shaft 842, and a drive component.

[0154] The housing 841 includes a cylindrical body and flanges located at both ends of the cylindrical body. The flange furthest from the fixed cylinder 81 is detachably connected to the cylindrical body by fasteners, and the flange is flush with the outer periphery of the cylindrical body. The flange closest to the fixed cylinder 81 is welded to the cylindrical body, and the flange protrudes outward from the cylindrical body, the portion of which is detachably connected to the fixed cylinder 81 by fasteners.

[0155] Both ends of the drive shaft 842 are provided with limiting shoulders, each corresponding to one of the two flanges. Each limiting shoulder abuts against the inner circumference of the corresponding flange, thereby restricting the axial movement of the drive shaft 842 along the housing 841. Specifically, the limiting shoulders are all located inside the cylinder, and both ends of the drive shaft 842 pass through the corresponding flanges.

[0156] A gear 8421 protrudes outward from the middle of the drive shaft 842. Specifically, a boss is formed by the outward protrusion of the middle of the drive shaft 842, and a ring of teeth is arranged around the outer periphery of the boss to form the gear 8421.

[0157] In this embodiment, the drive shaft 842 includes a gear shaft 8421 and a spline shaft coaxially arranged, and the gear shaft 8421 and the spline shaft are axially connected. The spline shaft is located at the end of the gear shaft 8421 facing the locking rod 82, and the gear 8421 is mounted on the gear shaft 8421. The spline shaft is connected to the locking rod 82. The gear shaft 8421 and the spline shaft are connected by a flat key or spline capable of transmitting torque.

[0158] The connection between the splined shaft and the locking rod 82 enables the connection between the drive shaft 842 and the locking rod 82. The connection between the splined shaft and the locking rod 82 is the same as that in the first embodiment, where the end of the splined shaft near the locking rod 82 has an external spline that extends into the internal spline hole at the drive end of the locking rod 82, forming a sliding spline pair that can both transmit torque and slide along the axis. The spline shape of this sliding spline pair can be a rectangular spline or an involute spline, and the axial sliding range of the sliding spline pair is greater than the working stroke L of the locking rod 82. Therefore, the rotation of the gear 8421 shaft is transmitted to the locking rod 82 through the splined shaft, causing the gear 8421 shaft and the locking rod 82 to rotate synchronously. Simultaneously, the presence of the sliding spline pair allows the locking rod 82 to freely extend and retract axially.

[0159] The drive unit includes a cylinder 843 disposed below the gear 8421 and a piston rod 844 disposed within the cylinder 843. The axes of both the cylinder 843 and the piston rod 844 are perpendicular to the axis of the drive shaft 842. The axis of the cylinder 843 does not intersect with the axis of the housing 841, and the axis of the cylinder 843 is located below the axis of the housing 841.

[0160] Preferably, the axis of cylinder 843 is located on the center plane of the axial length of gear 8421.

[0161] A meshing port for a corresponding gear 8421 is provided in the middle of the cylinder barrel 843. Here, "middle" refers to the axial center of the cylinder barrel 843. In this embodiment, the cylinder barrel 843 includes a barrel body and end caps located at both ends of the barrel body, with the end caps detachably connected to the barrel body. The meshing port is located on the barrel body, and the barrel body and the housing 841 together form a closed space.

[0162] The piston rod 844 has a rack in the middle that meshes with the gear 8421. The rack meshes with the gear 8421 through a meshing port. That is, in this embodiment, the locking device 8 drives the locking rod 82 to extend or retract through the meshing of the gear 8421 and the rack.

[0163] Gear 8421 and rack form a gear rack pair. In this embodiment, the module m of the gear rack pair is 4mm. Gear 8421 is provided on the shaft with a standard involute cylindrical gear 8421 with a pressure angle of 20°, a tooth width of 40mm, and a tooth number z of 30. The corresponding meshing section length on the rack is 335mm.

[0164] Since the axis of cylinder 843 is located on the center plane of the axial length of gear 8421, it ensures that gear 8421 and rack can mesh better.

[0165] Specifically, the piston rod 844 includes a middle section and two ends located at both ends of the middle section, with the outer diameter of the two ends being larger than the outer diameter of the middle section. The upper surface of the middle section is radially spaced from the inner surface of the cylinder 843, and a rack is provided on the middle section.

[0166] Furthermore, the length L3 and stroke L4 of the piston rod 844 are both not less than φz / 360, where φ is the rotation angle of the locking rod 82 and z is the number of teeth of the gear 8421. The total length L5 of the cylinder 843 is greater than or equal to the sum of the length L3 and the stroke L4 of the piston rod 844, that is, L5≥L3+L4.

[0167] Both ends of the piston rod 844 are equipped with sealing rings 845 to divide the space at both ends of the cylinder 843 into two independent chambers. Hydraulic oil with a pressure difference is introduced into the two chambers, which drives the piston rings to reciprocate axially within the housing 841, causing the gear 8421 to rotate, which in turn drives the drive shaft 842 to rotate, thereby driving the locking rod 82 to rotate, thus extending or retracting the locking rod 82. Specifically, both ends of the cylinder 843 are respectively provided with a first oil port 8431 and a second oil port 8432.

[0168] Figure 11 A schematic diagram of the control valve assembly is shown; see reference. Figure 11 The control valve assembly also includes two hydraulic locks arranged in parallel, each corresponding to one of the two chambers of cylinder 843. Each hydraulic lock includes a relief valve 871 and a hydraulically controlled check valve 872 arranged in parallel. The control valve assembly also includes a shut-off valve 873, which is located between the chamber and the hydraulic lock.

[0169] The working principle of locking device 8 is as follows:

[0170] Hydraulic oil with a pressure difference is injected into the two chambers of cylinder 843, causing piston rod 844 to move axially along housing 841. This, in turn, drives gear 8421 to rotate clockwise or counterclockwise. When gear 8421 rotates, it drives locking rod 82 to rotate via splined shaft, causing locking rod 82 to extend or retract axially. The extension and retraction of locking rod 82 are achieved by controlling the pressure difference between the two chambers.

[0171] Both ends of the piston rod 844 are provided with adjusting screws 876 and adjusting shims 877. The stroke range of the piston rod 844 within the cylinder 843 can be adjusted by adjusting the thickness of the adjusting shims 877. In this embodiment, the maximum adjustment range of the adjusting screws 876 is -21mm to 21mm, and correspondingly, the stroke adjustment range of the locking rod 82 is -1mm to 1mm.

[0172] The housing 841 is provided with a filling / draining oil hole, and a filling / draining oil screw 8411 is provided at the filling / draining oil hole. After the drive mechanism is assembled, hydraulic oil is filled into the housing 841 through the filling / draining oil hole, and then the filling / draining oil screw 8411 is tightened. The housing 841 is filled with hydraulic oil to balance the pressure on the housing 841 when the locking device 8 is underwater.

[0173] In this embodiment, the manual drive lever 88, locking screw 891, position monitor 893, and other features of the locking device are the same as those in the first embodiment, and can be referred to the description of the first embodiment, so they will not be repeated here.

[0174] The multiple locking devices of the riser support device can all be the locking devices in the first embodiment, or all be the locking devices in the second embodiment, or may simultaneously include the locking devices in both embodiments. When both the first and second embodiment locking devices are included, preferably, the locking devices in the first embodiment are evenly arranged circumferentially, and the locking devices in the second embodiment are also evenly arranged circumferentially. Further, the locking devices in the first embodiment are arranged in pairs, and the paired locking devices are located on the same diameter of the support member. The locking devices in the second embodiment are also arranged in pairs, and the paired locking devices are located on the same diameter of the support member.

[0175] Regardless of the specific combination of locking devices used in the riser support system, all locking devices are connected in parallel and via hydraulic lines to a remote monitoring system and a hydraulic power station on deck 10 of the ship. The remote monitoring system receives and displays the position signals of the locking rods monitored by the position monitors of each locking device. The hydraulic power station supplies hydraulic oil to the locking devices. In this embodiment, the hydraulic oil pressure supplied by the hydraulic power station is 34.5 MPa.

[0176] See Figure 12 The riser support device 20 also includes a pressure reducing valve 92, used to adjust the hydraulic oil pressure entering the locking device, thereby adjusting the driving force of the locking rod. In this embodiment, the pressure reducing valve 92 is a manual pressure reducing valve. The valve body of the pressure reducing valve 92 is located on the hydraulic pipeline, and the operating handle is installed on the control station panel on the deck for easy operation.

[0177] The riser support device also includes a directional valve 93 for controlling the flow direction of hydraulic oil, enabling remote operation of the locking and unlocking of the locking device from the deck. In this embodiment, the directional valve 93 is a three-position four-way directional valve and is manually operated. The valve body of the directional valve 93 is located on the hydraulic pipeline, and the operating handle is mounted on the control station panel on the deck for convenient operation.

[0178] The riser support device 20 also includes a pressure gauge and a pressure sensor. The pressure sensor is used to monitor the pressure in the hydraulic circuit, and the pressure gauge is used to display the pressure.

[0179] The riser support device 20 also includes a limiting mechanism to prevent the riser suspension head from sliding down within the support member 6, thus ensuring that the riser suspension head 50 is suspended within the support member 6. Limiting mechanisms are provided at both the upper and lower parts of the support member 6. Each limiting mechanism includes multiple limiting elements 91 evenly arranged around the outer periphery of the support member, with the multiple limiting elements 91 located in the same plane.

[0180] In this embodiment, the number of limiting members 91 is even, thus they are arranged in pairs.

[0181] Specifically, the limiting component 91 includes a limiting block and a hydraulic power component that drives the limiting block to move. The hydraulic power component drives the limiting block to move. The limiting block is inclined, and the angle between it and the horizontal plane is acute. Multiple limiting blocks approach each other and can abut against the riser suspension head, preventing the riser suspension head from sliding down.

[0182] Furthermore, the limiting member 91 also includes a sensor for detecting the position of the limiting block, thereby enabling remote monitoring on the deck.

[0183] In the riser support device 20, the locking device bears the axial pressure of the locking rod, and the limiting component bears the vertical pressure. That is, the locking device bears the horizontal load from the end of the riser, and the limiting component bears the vertical load of the riser. Each component has a clear and simple function, which reduces the complexity of the riser support device 20 and makes it less prone to damage, enabling it to reliably serve underwater for a long time.

[0184] This application also provides a method for installing and connecting a riser 40, using the aforementioned riser support device 20. The method includes the following steps:

[0185] S1. Lower a traction cable from the FPSO and pass it through the support member 6.

[0186] Specifically, this step is completed before the FPSO is launched or before it enters the target sea area.

[0187] S2. Provide a riser suspension head 50, and connect one end of the riser suspension head 50 to the end of the riser 40, and connect the riser suspension head 50 to the traction end of the traction cable; wherein, the outer diameter of the riser suspension head 50 is smaller than the inner diameter of the support member 6.

[0188] Specifically, the outer diameter of the riser suspension head 50 is smaller than the inner diameter of the support member 6, so that it can be inserted into the support member 6.

[0189] The upper or lower part of the riser suspension head 50 is provided with an outwardly protruding part, which has an inclined surface that slopes inward from top to bottom, and the inclined surface is parallel to the inclined direction of the limiting block.

[0190] During the installation of riser 40, riser 40 is located on the workboat adjacent to the FPSO. The connection between riser suspension head 50 and riser 40, as well as the connection between riser suspension head 50 and towing cable, are completed on the workboat.

[0191] S3. The riser suspension head 50 is inserted into the support member 6 from bottom to top by the traction cable, and the riser suspension head 50 is suspended in the support member 6.

[0192] Specifically, the traction cable moves upward, causing the riser suspension head 50 to extend into the support member 6. In practical applications, the traction end moves by the winch located on the FPSO deck winding the traction cable, causing the traction cable to move upward from the bottom of the support member 6.

[0193] After the riser suspension head 50 extends into the support member 6, the riser suspension head 50 is suspended inside the support member 6 by the limiting member 91 limiting the riser suspension head 50.

[0194] Specifically, the limiting member on the drive support 6 extends out and stops the protrusion on the riser suspension head 50, preventing the riser suspension head 50 from sliding down and thus suspending the riser suspension head 50.

[0195] The support member 6 is provided with limiting members 91 at both the upper and lower parts. In actual application, the upper limiting member 91 or the lower limiting member 91 can be used to stop the movement. Either one can be selected, depending on the actual situation.

[0196] S4. Extend the locking rod of the driving locking device and abut against the riser suspension head 50 to lock the riser suspension head 50.

[0197] Specifically, the locking rods of the locking device are extended by the remote monitoring system on the FPSO, and multiple locking rods simultaneously contact the riser suspension head 50 to achieve locking. In this application, the operator only needs to control the remote monitoring system on the deck to extend the locking rods of the locking device and complete the locking operation of the riser suspension head 50.

[0198] Because all the locking devices of the riser support device 20 are connected in parallel, at the start of the locking operation, the hydraulic oil pressure entering the locking devices is relatively low because it only needs to overcome friction. The locking rod with low frictional resistance contacts the riser suspension head 50 first and then stops moving. Under the continuous action of the hydraulic oil, the locking rods of the other locking devices will sequentially contact the riser suspension head 50 and stop moving, thus achieving a "passive" synchronous locking action of all locking devices. After the locking rods of all locking devices have contacted the riser suspension head 50, the hydraulic oil pressure will gradually rise to the set output pressure of the pressure reducing valve 92, indicating that the locking work has been completed and the hydraulic power station can be shut off. At this time, the locking devices enter a self-locking state, always maintaining reliable locking of the riser suspension head 50.

[0199] Multiple locking devices are required to tightly hold the fixed riser suspension head 50, ensuring its secure and stable position within the support member 6 and guaranteeing a stable and sealed transmission channel. Therefore, the stroke of each locking rod is the difference between the inner diameter of the support member 6 and the outer diameter of the riser suspension head 50. When the riser suspension head 50 is pulled into the support member 6, the diameter difference makes it impossible to guarantee coaxiality between the riser suspension head 50 and the support member 6, resulting in eccentricity—that is, the axis of the riser suspension head 50 deviates from the axis of the support member 6. To address this eccentricity, the locking device in this application can reliably stop and maintain locking capability at any position within the entire stroke range of the locking rod, thus still firmly holding the fixed riser suspension head 50.

[0200] S5. Connect the riser suspension head 50 to the ship side pipeline 30 to achieve the connection between the riser 40 and the ship side pipeline 30.

[0201] Since the riser suspension head 50 is already locked into the riser support device 20, when connecting the riser suspension head 50 to the ship side pipeline 30, only the operator needs to go into the water to perform the connection operation, such as tightening the fasteners. The operator does not need to bear any load, which greatly reduces the difficulty of operation and improves safety.

[0202] The process of releasing the riser 40 is the reverse of the above installation and connection process: first, disconnect the riser suspension head 50 from the ship side pipeline 30, then connect the riser suspension head 50 to the towing cable, then release the locking device from the riser suspension head 50, release the stop of the limit member 91 on the riser suspension head 50, then lower the towing cable, disconnect the riser suspension head 50 from the riser 40, and complete the release operation.

[0203] The tightening operation of the riser installation and connection method in this embodiment does not require divers to descend or underwater robots to perform underwater operations. Operators can complete the work on deck, significantly reducing worker workload and the impact of inclement weather, thus improving operational safety and efficiency. The entire installation and connection method only requires underwater connection when connecting the riser suspension head and the ship's side pipeline; this operation is weightless and only requires connection, making it easy to perform.

[0204] Although the invention has been described with reference to several typical embodiments, it should be understood that the terminology used is illustrative and exemplary, and not restrictive. Since the invention can be embodied in many forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A locking device, characterized in that, include: The fixed cylinder is hollow inside and has a first internal thread on its inner circumference; A locking rod is inserted into the fixed cylinder; the axis of the locking rod is coaxial with the fixed cylinder, and its two ends are a driving end and a locking end, respectively. The outer circumference of the locking rod is provided with a first external thread that is adapted to the first internal thread, so that the locking rod can rotate relative to the fixed cylinder; the first internal thread and the first external thread form a first helical pair, and the first helical pair is self-locking. A driving mechanism is provided at the end of the fixed cylinder near the driving end and is connected to the driving end to drive the locking rod to rotate, so that the locking end extends outward from the fixed cylinder or retracts into the fixed cylinder; The drive mechanism includes: The shell is hollow inside; the axis of the shell is parallel to the axis of the fixed cylinder; A drive shaft passes through the housing and extends out of the housing at both ends; the axis of the drive shaft is parallel to the axis of the housing, and the drive shaft is connected to the drive end of the locking rod. A driving component, which is connected to the driving shaft; The driving component can reciprocate through hydraulic differential, thereby driving the drive shaft to rotate and causing the locking rod to rotate and move axially. The locking device also includes a manual drive lever; The drive shaft has a through hole extending through its axis. The drive end of the locking rod has a slot with an opening facing the drive shaft. The manual drive rod passes through the through hole and extends into the slot, and is connected and fixed to the locking rod. The end of the manual drive rod away from the locking rod extends out of the housing.

2. The locking device according to claim 1, characterized in that, The relationship between the thread helix angle λ and the equivalent friction angle ρ' of the first screw pair satisfies: λ≤ρ', where λ= arctan(S / (πd 2 )), ρ'=arctan(f / cos(α / 2)), f is the friction coefficient of the first helical pair, α is the thread profile angle, S is the lead, and d is the mean diameter of the first external thread; The relationship between the working stroke L1 of the locking rod, the lead S1 of the first screw pair, and the rotation angle φ1 of the locking rod is as follows: L1 = φ1 × S1 / 360; The thread profile of the first helical pair is a trapezoidal thread, a sawtooth thread, or a rectangular thread.

3. The locking device according to claim 1, characterized in that, The driving component includes a piston ring disposed between the housing and the driving shaft, and the piston ring is capable of reciprocating along the axial direction of the driving shaft by hydraulic differential. The inner circumference of the housing is provided with a second internal thread, and the outer circumference of the drive shaft is provided with a third external thread; the outer circumference of the piston ring is provided with a second external thread adapted to the second internal thread, and the inner circumference is provided with a third internal thread adapted to the third external thread. The second internal thread and the second external thread form a second helical pair, and the third internal thread and the third external thread form a third helical pair. The rotation directions of the second helical pair and the third helical pair are opposite. Neither the second nor the third helical pair is self-locking.

4. The locking device according to claim 3, characterized in that, A first sealing ring is provided between the outer circumference of the piston ring and the housing, and a second sealing ring is provided between the inner circumference of the piston ring and the drive shaft. The first sealing ring and the second sealing ring are respectively located at both ends of the piston ring in the axial direction, so as to divide the space of the housing on both sides of the piston ring into two independent cavities, and hydraulic oil with a pressure difference is introduced into the two cavities.

5. The locking device according to claim 3, characterized in that, The housing has a receiving groove on its inner periphery away from the end of the fixed cylinder, and the opening of the receiving groove faces the axis of the housing. The drive shaft has a structure that is thicker in the middle and thinner at both ends. It includes a middle section, a first connecting section and a second connecting section located at both ends of the middle section. The outer diameter of the middle section is larger than the outer diameter of the first connecting section and the outer diameter of the middle section is larger than the outer diameter of the second connecting section. The second connecting section is close to the locking rod. The outer circumference of the first connecting section is provided with an external connecting thread, and a locking nut is screwed onto the external connecting thread. A bearing is provided between the drive shaft and the housing, the bearing is located in the receiving groove, and the bearing is located between the locking nut and the intermediate section.

6. The locking device according to claim 5, characterized in that, The housing has a protrusion at the end near the fixed cylinder, the protrusion is away from the fixed cylinder, and an adjusting nut is screwed to the outer periphery of the protrusion. The adjusting nut abuts against the end of the piston ring near the fixed cylinder, and an adjusting shim is provided between the bearing and the intermediate section.

7. The locking device according to claim 3, characterized in that, The rotation angle φ of the drive shaft is greater than or equal to the rotation angle required by the locking rod, and the stroke L2 of the piston ring is greater than or equal to (S2+S3)L1 / S1, where S1, S2 and S3 are the leads of the first helical pair, the second helical pair and the third helical pair, respectively, and L1 is the working stroke of the locking rod.

8. The locking device according to claim 1, characterized in that, A gear protrudes outward from the middle of the drive shaft; The driving component includes a cylinder disposed below the gear and a piston rod disposed inside the cylinder. The axes of the cylinder and the piston rod are both perpendicular to the axis of the driving shaft. A meshing port corresponding to the gear is opened in the middle of the cylinder. A rack that meshes with the gear is provided in the middle of the piston rod. The rack meshes with the gear through the meshing port.

9. The locking device according to claim 8, characterized in that, Both ends of the piston rod are provided with sealing rings to divide the space at both ends of the cylinder into two independent cavities; The axis of the cylinder is located on the center plane of the axial length of the gear; The axis of the cylinder does not intersect the axis of the housing.

10. The locking device according to claim 8, characterized in that, The length L3 and stroke L4 of the piston rod are both not less than φ1z / 360, where φ1 is the rotation angle of the locking rod, z is the number of teeth of the gear, and the total length L5 of the cylinder is greater than or equal to the sum of the length L3 and stroke L4 of the piston rod.

11. The locking device according to claim 8, characterized in that, The drive shaft includes a gear shaft and a spline shaft arranged coaxially. The spline shaft is located at the end of the gear shaft facing the locking rod. The gear is mounted on the gear shaft. The spline shaft is connected to the locking rod. The piston rod is provided with adjusting screws and adjusting shims at both ends, with the adjusting shims located between the adjusting screws and the piston rod.

12. The locking device according to claim 8, characterized in that, The housing includes a cylindrical body and flanges located at both ends of the cylindrical body, the flanges being detachably connected to the cylindrical body; Both ends of the drive shaft are provided with limiting shoulders, and the two limiting shoulders correspond one-to-one with the two flanges. Each limiting shoulder is located inside the cylinder and abuts against the inner circumference of the corresponding flange to restrict the axial sliding of the drive shaft. The two ends of the drive shaft pass through corresponding flanges.

13. The locking device according to claim 1, characterized in that, An external spline is fitted on the end of the drive shaft facing the locking rod, and an internal spline hole is provided on the drive end of the locking rod. The external spline is adapted to the internal spline hole, and the external spline extends into the internal spline hole. The axial sliding stroke of the external spline and the internal spline hole is greater than the working stroke of the locking rod.

14. The locking device according to claim 1, characterized in that, The locking device also includes a position monitoring sensor for detecting the position of the locking rod. The position monitoring sensor is electrically connected to the control station to transmit the position signal of the locking rod to the control station.

15. The locking device according to claim 1, characterized in that, The locking device further includes a locking screw; a boss is provided at one end of the housing away from the fixed cylinder, the manual drive rod passes through the boss, the axis of the locking screw is perpendicular to the axis of the manual drive rod, and the locking screw can pass through the boss to abut against the manual drive rod and lock the manual drive rod.

16. The locking device according to claim 1, characterized in that, The locking device also includes a control valve assembly, which is fixed to the outside of the housing. The control valve assembly includes two hydraulic locks arranged in parallel, and the two hydraulic locks are arranged one-to-one with the two cavities inside the housing. Each hydraulic lock includes an overflow valve and a hydraulically controlled check valve arranged in parallel. The control valve assembly also includes a shut-off valve, which is located between the hydraulic lock and the two cavities, enabling the two cavities to be isolated or connected.

17. A riser support device, characterized in that, The device includes a support member and a plurality of locking devices evenly arranged around the outer periphery of the support member. The support member is cylindrical, and the locking devices are as described in any one of claims 1 to 16.

18. The riser support device according to claim 17, characterized in that, Multiple locking devices are connected in parallel and connected to a remote monitoring system and a hydraulic pump station on the deck via hydraulic pipelines; The riser support device also includes a reversing valve for switching the flow direction of the hydraulic oil entering the locking device; The riser support device also includes a pressure reducing valve for adjusting the hydraulic oil pressure entering the locking device.

19. The riser support device according to claim 17, characterized in that, The riser support device also includes a limiting mechanism; the limiting mechanism is provided at both the upper and lower parts of the support member; Each of the limiting mechanisms includes a plurality of limiting members evenly arranged on the outer periphery of the support member, and the plurality of limiting members are located in the same plane; Each of the aforementioned limiting components includes a limiting block and a hydraulic power component for driving the limiting block to move. The limiting block is inclined and forms an acute angle with the horizontal plane. Multiple limiting blocks together abut against the riser suspension head.

20. A method for installing and connecting a riser pipe, characterized in that, The installation and connection method employs the riser support device as described in any one of claims 17 to 19, and the installation and connection method includes the following steps: A traction cable is lowered from the FPSO and passed through the support member. A riser suspension head is provided, and one end of the riser suspension head is connected to the end of the riser, and the riser suspension head is connected to the traction end of the traction cable; wherein, the outer diameter of the riser suspension head is smaller than the inner diameter of the support member. The riser suspension head is inserted into the support member from bottom to top by the traction cable, and the riser suspension head is suspended in the support member; The locking rod of the locking device is extended and abuts against the riser suspension head to lock the riser suspension head; The riser suspension head is connected to the ship's side pipeline to achieve the connection between the riser and the ship's side pipeline.

21. The method for installing and connecting a riser according to claim 20, characterized in that, The step of suspending the riser suspension head within the support member includes: The limiting member located on the support extends and stops the protrusion on the riser suspension head, preventing the riser suspension head from sliding down and thus suspending the riser suspension head.

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