Underwater lifting device for offshore fixed platform and using method

Abstract

The invention relates to an underwater lifting device for an offshore fixed platform and a using method, and belongs to the technical field of ocean engineering.The device mainly comprises a motorized guide rail, a lifting platform and a traction device.The motorized guide rail can be lowered from any direction of a platform deck and comprises a guide rail module which is formed by hinging a plurality of units and can be rolled up; the mechanical hoop mechanism is used for locking the lifting platform on the platform jacket in a multi-point mode, the lifting platform is matched with the guide rail cable for guiding through the guide wheel set, and the lifting platform is meshed with the unfolded guide rail module through a ratchet wheel for preventing inversion; in the working process, the motorized guide rails are arranged and rigidly locked to form the low-shaking rails, then the lifting platform carrying equipment is driven to be lowered to the designated water depth along the rails for hovering operation, and the problems that due to a traditional hoisting mode, the equipment is prone to being interfered by ocean currents, and shaking rotation is large are solved; and maneuvering, stability, laying and recovery of the marine environment sensing equipment from the fixed platform are realized.

Description

Technical Field

[0001] This invention relates to the field of marine engineering technology, specifically to an equipment deployment system for fixed marine research or production platforms, and more particularly to an underwater lifting device capable of mobile deployment from any position on the platform, and enabling the onboard marine environmental sensing equipment to achieve low swaying and anti-rotation stable hovering at a specified water depth. Background Technology

[0002] With the deepening of marine resource exploration, marine environmental monitoring and marine scientific research, long-term, fixed-point observation and experimental activities based on offshore fixed platforms (such as jacket research platforms, oil production platforms, etc.) are becoming more and more frequent. Such activities usually require the safe and accurate deployment of various marine environmental sensing devices, such as sound velocity profilers, temperature-depth chains, seabed seismometers, and current meters, from the platform deck to seawater or seabed at different locations and depths.

[0003] Currently, conventional techniques for underwater deployment of such equipment mainly rely on cranes or simple lifting devices mounted on platform decks. This traditional method has significant drawbacks: First, the equipment is directly suspended by cables, forming a complex pendulum-fluid-structure interaction system. Under the influence of ocean currents and waves prevalent in the surface and mid-layers, the equipment experiences significant horizontal drift, swaying, and rotation around the suspension point. This unstable motion can prevent the equipment from accurately reaching the preset measurement points, and the violent shaking and rotation can severely interfere with the normal operation of sensing equipment. Therefore, there is an urgent need in this field for a dedicated lifting device that can be integrated into a fixed offshore platform, has the ability to be flexibly deployed from any direction around the platform, and can provide stable, low-sway, and anti-rotation support for underwater equipment. This device should be able to overcome ocean current interference, achieve precise hovering of the equipment at any specified water depth, and possess good recoverability and reusability to meet the needs of different scientific research missions. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a mobile underwater lifting device based on a fixed offshore platform. This device is designed to solve the technical problems of unstable underwater attitude of equipment caused by traditional hoisting methods, which makes the equipment susceptible to drifting and rotation due to ocean currents. It enables the safe, stable, and accurate deployment and hovering of marine environmental sensing equipment from the platform deck to a designated underwater location.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: An underwater lifting device for a fixed offshore platform includes a motorized guide rail, a traction device, and a lifting platform. The motorized guide rail constitutes the main guiding and supporting structure of the underwater lifting device, and includes a first winch, two parallel guide rail cables, a guide rail module connected between the two guide rail cables, and a tensioning counterweight fixed to the end of the guide rail module. The first winch is fixedly installed on the deck (dry end) of the fixed offshore platform. Each guide rail cable has a fixed end and a free end. The fixed end is anchored to the platform structure or the base of the first winch, and the free end is wound on the drum of the first winch. By driving the first winch to extend and retract the free end of the guide rail cable, the unfolding and rewinding of the entire motorized guide rail can be controlled. The guide rail module is formed by multiple guide rail units with the same structure being hinged sequentially through a pivot, forming a flexible chain structure with longitudinal load-bearing capacity. The tensioning counterweight is fixedly connected to the end of the guide rail module, i.e., the underwater wet end. Its function is twofold: firstly, to provide a counterweight for the guide rail when it is lowered, and secondly, to serve as the axis when the guide rail module is wound up.

[0006] The lifting platform is used to carry marine environmental sensing equipment. It includes a carrying frame, at least four ratchet wheels installed at the bottom of the carrying frame, and at least two sets of guide wheel assemblies installed at the top of the carrying frame. The carrying frame forms the equipment mounting base. The two sets of guide wheel assemblies respectively cooperate with two guide rail cables. The groove profile of the ratchet wheels is adapted to the outer diameter height of the guide rail cables, ensuring that the lifting platform can smoothly rise and fall along the cables and restricting its horizontal lateral displacement. The teeth of the ratchet wheels mesh with a specific structure on the guide rail module. When the lifting platform is located in the guide rail module section, the meshing of the ratchet wheels with the guide rail module can effectively prevent the lifting platform from accidentally sliding down under the action of gravity or ocean currents, while allowing it to move upward or descend in a controlled manner under the action of traction force.

[0007] The traction device, independent of the motorized guide rail, is used to drive the lifting platform to move along the guide rail. It includes a second winch and a traction cable. The second winch is fixed to the platform deck, and one end of the traction cable is wound around the second winch, while the other end is connected to the top of the lifting platform's load rack. By controlling the second winch, the lifting platform and its load equipment can be raised and lowered.

[0008] Furthermore, to achieve low-sway hovering at any water depth, the horizontal supports of the offshore fixed platform are equipped with multiple mechanical clamps controlled by a unified controller at intervals along the vertical direction. When the mobile guide rail is lowered to the target depth, the controller can instruct the mechanical clamps at the corresponding positions to lock the guide rail modules passing through them onto the horizontal supports of the guide rail, thereby connecting the multiple points of the mobile guide rail to the rigid platform structure, greatly enhancing its overall current resistance stiffness and effectively suppressing the swaying and torsion of the guide rail and the lifting platform caused by ocean currents.

[0009] Compared with the prior art, the beneficial effects of the present invention are: Because the motorized guide rail adopts a modular articulated design and relies on the steel cable for deployment, its layout is not limited by the original structure of the platform. By operating the first winch, the guide rail can be lowered from any required position on the edge of the platform deck and laid along the outside of the platform jacket, which solves the problem that the traditional fixed guide rail cannot flexibly meet the observation needs of different orientations. This application employs a composite stabilization mechanism combining rigid guide rail guidance and multi-point rigid locking. The lifting platform is tightly coupled with the guide rail cable through the guide wheel assembly, restricting the two translational degrees of freedom in the horizontal plane. The engagement of the ratchet with the rigid guide rail module provides reliable longitudinal backstop. More importantly, the mechanical clamps lock the deployed guide rail module to the horizontal brace of the jacket frame, improving the rigidity of the structure. This structure can effectively resist the impact of ocean currents, minimizing the horizontal displacement, sway amplitude, and rotation angle of the mounted equipment, thus meeting the requirements of marine environmental sensing equipment for a stable working platform. Mechanical clamps are arranged in multiple layers along the guide frame. With the precise control of the first winch, the motorized guide rail can be stably stopped at any water depth from near the sea surface to above the seabed. The lifting platform is pulled by the second winch and can move precisely on the locked guide rail and stop at any point within the guide rail range, thereby realizing the suspension operation of the load equipment at any target water depth. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the overall structure of the underwater lifting device of the present invention; Figure 2 This is a schematic diagram of the upper structure of the guide rail unit of the present invention; Figure 3 This is a schematic diagram of the lower structure of the guide rail unit of the present invention; Figure 4 This is a schematic diagram of the lifting platform structure of the present invention; Figure 5 This is a schematic diagram of the tensioning counterweight structure of the present invention.

[0011] In the diagram: 1 guide rail module, 11 guide rail unit, 12 connecting shaft, 111 base plate, 112 ridge plate, 113 support block, 114 support block, 115 connecting block, 116 slot, 117 slot. 2 lifting platform, 21 ratchet, 22 cargo rack, 23 guide wheel assembly; 3 tensioning counterweights, 31 counterweight shafts, 32 limit plates; 4. Guide rail cable, 5. Traction cable, 6. Offshore platform jacket, 7. Mechanical clamp. Detailed Implementation

[0012] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings, so that those skilled in the art can more clearly understand how to practice the present invention. Although the present invention has been described in conjunction with its preferred embodiments, these embodiments are merely illustrative and not intended to limit the scope of the invention.

[0013] See Figure 1-5 One embodiment of the present invention provides a mobile underwater lifting device for a jacket-type offshore scientific research platform. The offshore scientific research platform has a conventional jacket 6 structure, which consists of multiple vertical columns and horizontal and diagonal struts connecting the columns.

[0014] The underwater lifting device mainly includes a motorized guide rail, a lifting platform 2, and a traction device.

[0015] The mobile guide rail, serving as the basic track, is designed for mobile deployment and variable stiffness. It extends from the deck of the offshore research platform to the underwater target area, providing guidance and support for the lifting platform 2. The mobile guide rail mainly includes: The first winch (not shown in the figure) is fixedly mounted on the deck of the offshore research platform. The guide rail cable 4 is made of high-strength, corrosion-resistant, and low-elongation steel wire rope. There are two cables in total, which are arranged in parallel and spaced apart. One end of each cable is fixed to the deck of the offshore research platform by anchors, and the other end is wound around the drum of the first winch. When the first winch is working, its underwater length is controlled by synchronously winding and unwinding the free ends of the two cables. The guide rail module 1 is connected in series between two guide rail cables 4, and is formed by multiple identical guide rail units 11 and rotating shafts 12 being hinged together to form a long chain; the top end of the guide rail module 1, i.e. the dry end, is anchored to the edge structure of the platform deck through a hinge seat. The tensioning counterweight 3 is located at the lower end of the guide rail module 1, i.e., the wet end. It includes a cylindrical counterweight shaft 31 and two limiting discs 32 fixed at its two ends respectively. The diameter of the limiting discs 32 is larger than that of the counterweight shaft 31, and they are used to axially limit the winding guide rail module 1. The tensioning counterweight 3 can assist the guide rail in lowering and serve as the core reel during winding.

[0016] Specifically, the guide rail unit 11 consists of a long strip-shaped base plate 111 and a ridge plate 112 inclined and fixed to the center line of its top surface, which together form a main beam with a T-shaped cross section. The ridge plate 112 can enhance the longitudinal bending stiffness of the guide rail unit 11. At both ends of the base plate 111 in the width direction, there are support blocks 114 and connecting blocks 115 extending in the width direction, respectively. There are two support blocks 114 and two connecting blocks 115, which are arranged in a corresponding manner. The support blocks 114 have shaft holes, and the rotating shaft 12 passes through the support blocks 114 and connecting blocks 115 of two adjacent guide rail units 11 to realize the hinge between them. The axes of all hinge shafts are collinear, so that the entire guide rail module 1 can bend in the axial direction, thereby realizing the winding around the tension counterweight 3. Furthermore, at one end of the base plate 111 in the width direction and below the connecting block 115, a support block 113 is provided; the lower surface of the support block 113 is flush with the lower surface of the base plate 111, and at the other end of the base plate 111 in the width direction, i.e., at one end of the corresponding support block 114, a groove 117 matching the size and shape of the support block 113 is machined; when the guide rail module 1 is straightened and unfolded, two adjacent guide rail units 11 are connected by a pivot 12 and are relatively straightened. At this time, the support block 113 of the first unit near the deck end is precisely embedded in the groove 117 of the bottom of the base plate 111 of the second unit near the underwater end. This tenon-and-mortise type fit allows part of the weight of the second unit to be directly transferred to the base plate 111 of the first unit through the support block 113, effectively reducing the bending moment borne by the pivot 12 at the hinge point, and ensuring that after the connection of multiple units, the top surface of the entire guide rail module 1 can form a toothed track plane.

[0017] At both ends of the base plate 111 along its length, a slot 116 is formed. The slot 116 is an arc-shaped groove, the curvature of which matches the outer diameter of the guide rail cable 4. The two guide rail cables 4 are respectively inserted into this series of aligned slots 116. The depth and arc design of the slot 116 allow the guide rail unit 11 to rest on the two cables. The cables mainly bear the tension, while the guide rail unit 11 evenly transmits the local pressure to the cables and uses the tension of the cables to maintain its straightness. To further increase the contact area, the slot 116 can extend from the side of the base plate 111 to the corresponding position of the support block 113. When unfolded, the slot section on the support block 113 and the slot section of the base plate of the adjacent unit jointly support the cables.

[0018] The lifting platform 2 is a transport tool for the load equipment. During operation, it is mounted on two guide rail cables 4 and can move smoothly and reliably along the guide rail modules 1 under their guidance. It includes: The rack 22 is a rigid frame structure with an equipment mounting interface on the top for fixing various marine environmental sensing devices such as sound velocity profilers and instrument compartments. The guide wheel assembly 23 consists of two sets, symmetrically installed on both sides of the top of the carrier 22. Each guide wheel assembly 23 includes at least one grooved wheel and its supporting bearing seat. The groove shape of the grooved wheel matches the diameter of the guide rail cable 4, ensuring that the grooved wheel can be stably locked on the cable, constraining the horizontal movement of the lifting platform 2 within the vertical plane guided by the cable, while providing smooth rolling friction for easy lifting. There are four ratchet wheels 21, which are distributed in pairs on both sides of the bottom of the rack 22. The pitch of the ratchet wheels 21 and the spacing of the ridge plate 112 on the guide rail unit 11 form a meshing engagement.

[0019] The traction device independently drives the lifting platform 2, including a second winch (not shown in the figure) and a traction cable 5. The second winch is installed on the deck of the offshore research platform; one end of the traction cable 5 is connected to the drum of the second winch, and the other end is connected to the top of the load rack 22 of the lifting platform 2.

[0020] When the lifting platform 2 is above the guide rail module 1 and is supported only by the guide rail cable 4, the guide wheel assembly 23 at its top is the main guiding and load-bearing component. The grooved wheels tightly grip the cable, restricting the platform to the cable path. At this time, the bottom ratchet 21 is in an idle or non-contact state. When the lifting platform 2 descends to the area of ​​the guide rail module 1, the teeth of the four ratchet 21 at its bottom will fall into the gaps between the ridge plates 112 of the guide rail unit under the action of gravity. When the second winch releases the traction cable 5 in a controllable manner, causing the platform to descend, the teeth of the ratchet 21 move along the ridge plate 112. The inclined plane 12 slides over, allowing the lifting platform 2 to move downwards; when the second winch retracts the traction cable 5 and lifts the platform, the traction force overcomes the resistance of the ratchet 21 anti-reverse mechanism, causing the ratchet 21 to rotate in the opposite direction, thus smoothly climbing upwards along the tooth surface of the ridge plate 112; when the platform reaches the target depth and stops, the ratchet 21 automatically engages with the ridge plate 112 under the action of gravity to form a mechanical self-lock. At this time, the platform is locked in the vertical direction by the ratchet-ridge plate engagement mechanism and constrained in the horizontal plane by the grooved wheel-cable mechanism, providing an extremely stable temporary workstation.

[0021] In this embodiment, to further stabilize the posture of the underwater lifting device during operation, a mechanical clamp 7 is pre-installed at certain intervals along the vertical direction on the transverse support of the platform guide frame 6. Each mechanical clamp 7 has a built-in drive motor and clamping arm, and is remotely controlled wirelessly or wired by a unified controller located in the platform control room. The inner diameter of the mechanical clamp 7 is slightly larger than the cross-sectional size of the guide rail module 1. Under normal conditions, it is in the open state, allowing the guide rail module 1 to pass freely. When the clamping arm of the mechanical clamp 7 is closed, it can tightly clamp the guide rail module 1 passing through it onto the transverse support of the guide frame. This can apply rigid support constraints at multiple points to the guide rail module 1, thereby ensuring that the lifting platform 2 and the load equipment attached to it hardly sway or twist with the current. Instructions for use of this underwater lifting device: First, the coiled guide rail module 1 and its tensioning counterweight 3 are placed at the predetermined deployment position on the platform deck. The dry end of the guide rail module 1 is anchored, and the free end of the guide rail cable 4 is in a tightened state. The first winch is started, and the free ends of the two guide rail cables 4 are slowly released. Under the gravity of the tensioning counterweight 3, the guide rail module 1 is dragged off the deck and slides down along the outside of the platform jacket 6. Due to the hinge design between the guide rail units 11, it can naturally conform to the tilt angle and shape of the jacket. When the tensioning counterweight 3 reaches the target operating water depth, the first winch is stopped. At this time, the entire motorized guide rail is in a tilted and suspended state. Through the controller, multiple mechanical clamps 7 corresponding to the target water depth range are activated to lock the guide rail module 1 onto the cross brace of the jacket 6. After locking, the first winch can be slightly tightened to put the guide rail in a tensioned state, completing the rigid deployment. After the motorized guide rails are installed, the marine environmental measurement equipment is fixed on the cargo rack 22 of the lifting platform 2 on the deck. The guide wheel assembly 23 of the lifting platform 2 is inserted into the two pre-installed guide rail cables 4 by manual labor or auxiliary lifting equipment. Then, the second winch is started to release the traction cable 5. The lifting platform 2 begins to descend along the guide rails under its own weight and load. In the initial stage, it is guided by the guide wheel assembly 23 to slide down along the cable. When it descends and contacts the guide rail module 1, the ratchet 21 automatically engages with the ridge plate 112 and enters the engagement guidance stage. Then, the second winch is operated to lower the lifting platform 2 to the designated depth position on the guide rail module 1. The second winch is stopped, and the platform is self-locked and stopped by the ratchet mechanism. Since the guide rail module 1 has been rigidly fixed by the mechanical clamp 7, the ocean current disturbance here is minimal, and the platform and equipment are in a stable working state, and observation or measurement can begin. After the operation is completed, the second winch is started to retrieve the traction cable 5. The traction force overcomes the counterforce of the ratchet 21 and drives the lifting platform 2 to rise along the guide rail module 1 and the guide rail cable 4 until it returns to the deck. The equipment and the lifting platform 2 are unloaded. Then, through the controller, all the mechanical clamps 7 involved in locking are opened to release the rigid constraint on the guide rail module 1. Finally, the first winch is started to retrieve the free end of the guide rail cable 4. The cable pulls the end of the guide rail module 1, i.e. the tension counterweight 3, upward. During the retrieval process, the guide rail module 1 begins to coil around the counterweight shaft 31. Since the support block 113 has been dislodged from the support groove 117 of the adjacent unit and the units can rotate freely around the rotating shaft 12, the entire guide rail module 1 can be tightly and orderly coiled on the counterweight shaft 31. The two limiting discs 32 prevent the coiled layer from spreading out laterally. Finally, the entire motorized guide rail is wound back to its original storage state, completing the retrieval.

[0022] This invention expands the versatility of underwater lifting devices by adopting a mobile deployment mode, enabling low-cost deployment and lifting of scientific research equipment at any location on offshore research platforms. By first laying mobile guide rails and then assembling the underwater lifting platform, it also enables the scientific research equipment to hover at any depth with low sway. This provides a reliable, universal, and efficient engineering equipment solution for high-precision marine environmental observation and research, and has practical value and promising prospects for promotion.

[0023] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An underwater lifting device for a fixed offshore platform, characterized in that, include: A motorized guide rail, the proximal end of which is connected to the edge of the platform and the distal end of which extends underwater, the motorized guide rail including a flexible cable-like component and a guide rail module disposed thereon; A lifting platform, movably connected to a motorized guide rail, the lifting platform including a cargo rack; and A traction device is connected between the cargo rack and the platform to drive the lifting platform to move along the motorized guide rail; The offshore fixed platform has multiple spaced mechanical clamps on its jacket; the motorized guide rail has an extended state and a retracted state. In the extended state, the guide rail module is fixed to the jacket structure by the mechanical clamps.

2. The underwater lifting device for a fixed offshore platform according to claim 1, characterized in that, The motorized guide rail also includes: The first winch is installed on the deck of the fixed offshore platform; Two parallel, spaced-apart guide rail cables, each with a fixed end and a free end. The fixed end is fixed to the platform structure, and the free end is connected to the execution end of the first winch. The guide rail module includes multiple guide rail units that are hinged sequentially. The guide rail module is connected between the two guide rail cables. The end of the guide rail module near the platform is connected to the platform structure, and the other end is equipped with a tensioning counterweight.

3. The underwater lifting device for a fixed offshore platform according to claim 2, characterized in that: The guide rail unit includes a base plate and a ridge plate fixed on the base plate. The base plate is provided with a connecting part for hinged connection with adjacent guide rail units and a supporting and mating structure for supporting adjacent guide rail units.

4. The underwater lifting device for a fixed offshore platform according to claim 3, characterized in that: The supporting structure includes a support plate at one end of a guide rail unit and a slot at the corresponding end of an adjacent guide rail unit. The support plate is embedded in the slot when the guide rail module is unfolded, and the supporting surface of the support plate is flush with the bottom surface of the main beam of the guide rail unit where the slot is located.

5. The underwater lifting device for a fixed offshore platform according to claim 3, characterized in that, The lifting platform also includes a guide wheel assembly and multiple ratchet wheels installed at the bottom of the load cell; the guide wheel assembly is mounted on the load cell and cooperates with the guide rail cable to guide the load cell to move along the extension direction of the guide rail cable; the teeth of the ratchet wheels are adapted to the ridge plate provided on the guide rail module to achieve engagement.

6. The underwater lifting device for a fixed offshore platform according to claim 3, characterized in that: The guide rail unit has a slot at each of the two ends of its base plate to accommodate the guide rail cable.

7. The underwater lifting device for a fixed offshore platform according to claim 1, characterized in that: The traction device includes a second winch mounted on the platform deck and a traction cable connecting the second winch and the cargo rack.

8. The underwater lifting device for a fixed offshore platform according to claim 6, characterized in that: The slot has an arc-shaped structure.

9. The underwater lifting device for a fixed offshore platform according to claim 2, characterized in that: The tensioning counterweight includes a counterweight shaft and two limiting discs fixed at both ends of the counterweight shaft. The outer diameter of the limiting discs is larger than the outer diameter of the counterweight shaft. The far end of the guide rail module is fixedly connected to the counterweight shaft.

10. A method for using the underwater lifting device according to any one of claims 1-9, characterized in that, Includes the following steps: The mobile guide rail is deployed from a selected position on the deck of the fixed offshore platform, extending along the outside of the platform jacket to the target water depth area, and the mechanical clamps are used to lock the mobile guide rail onto the jacket. The lifting platform is mounted and lowered by installing the lifting platform equipped with marine environmental sensing equipment onto the pre-laid mobile guide rail, and then driving the lifting platform along the mobile guide rail to a designated working depth and hovering it through the traction device. After the operation is completed, the lifting platform is retrieved to the deck using the traction device. Then, the mechanical clamps are released from the motorized guide rails, and the motorized guide rails are wound up and retrieved to the platform deck or a nearby storage location.

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