Offshore construction wave compensation system and method

Abstract

This invention discloses a wave compensation system and method for marine engineering construction, featuring a hybrid active and passive wave compensation component capable of performing both active and passive wave compensation operations. It comprises a telescopic pipe supported by a carriage and universal joint, a double-drum hoisting winch, and a hydraulic cylinder connected to a moving pulley block. A logic-integrated hydraulic valve block, controlled by a PLC and a motion reference unit (MRU), supports a passive wave compensation mode (PHC) using high and low pressure accumulators as hydropneumatic springs, suitable for low sea states, and also supports an active wave compensation (AHC) mode for high sea states. The hydraulic circuit includes a dedicated bypass valve SV3, which instantaneously connects the piston and slide rod chamber of the hydraulic cylinder in the event of overpressure or overspeed, ensuring mechanical integrity. This system provides precise and energy-efficient vertical positioning of the lower discharge point of the telescopic pipe relative to the seabed to compensate for ship motion.

Description

Technical Field

[0001] This invention relates to the field of marine construction operation technology, and more specifically, to a wave compensation system and method for marine engineering construction. Background Technology

[0002] In marine construction operations, wave compensation systems are crucial for counteracting the vertical motion of vessels caused by waves. These systems ensure the stability, accuracy, and safety of operations such as drilling, lifting, and underwater installation. However, existing wave compensation systems often face challenges in achieving high precision and efficiency, especially in harsh sea conditions. This invention aims to address these challenges by using a standard two-chamber hydraulic cylinder (replacing the common three-chamber hydraulic cylinder), a logic control valve (valve block module), a directional proportional valve, a high-pressure accumulator, a low-pressure accumulator, and a hydraulic power unit (HPU). Summary of the Invention

[0003] The purpose of this invention is to address the problem of insufficient accuracy and efficiency of wave compensation systems in existing marine construction operations by providing a wave compensation system and method for marine engineering construction.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A wave compensation system for marine engineering construction, comprising: At least one dual-chamber hydraulic cylinder configured to drive a telescopic drop pipe; The hydraulic power unit (HPU) consists of an electric motor and a hydraulic pump; At least one high-pressure accumulator and at least one low-pressure accumulator are fluidly connected to the hydraulic cylinder; A logic control valve block, consisting of multiple directional control valves and a proportional flow control valve; and A control system consisting of a motion reference unit (MRU) and a programmable logic controller (PLC) is configured to drive the valve block in response to the motion of the ship.

[0005] Furthermore, the programmable logic controller is configured to perform manual or automatic selective switching between the following: A passive wave compensation (PHC) mode is applicable when the sea state wave height is below a predetermined threshold, enabling autonomous compensation by high-pressure and low-pressure accumulators; and In higher sea states, an active wave compensation (AHC) mode is used, in which the hydraulic power unit and logic control valve block drive the hydraulic cylinder according to the commands of the motion reference unit.

[0006] Furthermore, the logic control valve block includes a bypass valve SV3, which is configured to momentarily connect the piston chamber and piston rod chamber of the hydraulic cylinder when the sensed hydraulic cylinder speed or pressure exceeds a predetermined safety threshold.

[0007] Furthermore, the logic control valve block further includes: The first pilot-operated cartridge valve, SV4, is configured to regulate the flow of hydraulic oil between the high-pressure accumulator and the hydraulic cylinder; and The second pilot cartridge valve SV6 is configured to activate when the low-pressure accumulator reaches a specific pressure limit.

[0008] Furthermore, including: A double-drum hoisting winch is driven by an AC asynchronous variable frequency motor through a gearbox; The motor is equipped with variable speed control, which can adjust the winch speed according to the wave speed; and A movable pulley system guided by a rigid mechanical linear guide and driven by a hydraulic cylinder, wherein the hydraulic cylinder is controlled by a logic control valve block.

[0009] Furthermore, the motor and winch drum employ low-inertia components to facilitate a substantial instantaneous response to the adjusted bulge signal provided by the programmable logic controller.

[0010] Furthermore, the system provides real-time data on wave amplitude, velocity, and acceleration.

[0011] A wave compensation method utilizing the aforementioned wave compensation system includes the following steps: The lifting of the ship is measured using a motion reference unit, generating the original lifting signal; The original lifting signal is processed by a programmable logic controller (PLC), and an adjusted lifting signal is output. Drive the proportional flow control valve to regulate the flow of hydraulic oil from the high-pressure accumulator to the hydraulic cylinder; and Based on the adjusted lifting signal, the telescopic tube is moved relative to the vessel to maintain a substantially constant distance between the tube and the seabed.

[0012] Furthermore, it includes a safety regulation step in which the programmable logic controller monitors the pressure via sensor PT3 and closes the first valve SV4 when the high-pressure accumulator reaches its maximum pressure limit, while simultaneously activating the second valve SV5.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: it can perform active and passive wave compensation operations. When the waves are in low or medium sea states, the passive wave compensation mode can be adopted and activated, while the active wave compensation mode can be adopted and activated in higher sea states. It can provide accurate and energy-saving vertical positioning of the lower end discharge point of the telescopic pipe relative to the seabed to compensate for the ship's motion. The wave compensation system has better accuracy and efficiency. Attached image description: To better understand the various implementation examples described, please refer to the following detailed description in conjunction with the accompanying drawings, in which the same reference numerals denote corresponding parts throughout the drawings.

[0014] Figure 1 This is a telescopic rockfall pipe system with wave compensation components.

[0015] Figure 2 Schematic diagram of a hydraulic system for vertical wave compensation.

[0016] Figure 3 This is the user screen interface used to control the wave vertical compensation system. Detailed Implementation

[0017] Refer to the attached diagram for the system components: like Figure 1 As shown, the telescopic tube 88 is suspended below the universal joint by the wire rope 83, passes through two sets of guide wheels, and is connected to the double drum hoisting winch 81 through the front pulley of the AHC hydraulic cylinder 84.

[0018] At the start of operation, piston 84 of the AHC hydraulic cylinder is located in the middle of the cylinder body (the linear positioning sensor is installed inside the hydraulic cylinder slide rod). Operate the hoisting winch to lower the telescopic jacking pipe to the desired working position (e.g., the lower end of the jacking pipe is one meter from the seabed). At this point, stop operating the hoisting winch.

[0019] The AHC hydraulic cylinder 84 reciprocates according to the operating system commands, and the reciprocating distance is executed according to the control system commands. This controls the up and down movement of the telescopic pipe, moving in the opposite direction to the ship or waves, thereby keeping the pipe tip within a certain distance required for the operation and preventing the pipe from going too high or too low and hitting the seabed, which could cause an accident.

[0020] When the waves are in low to medium sea states, the passive wave compensation mode can be used and activated. In higher sea states, the active wave compensation mode is used and activated. The entire system, including the hydraulic power unit, high and low pressure accumulators, logic-integrated hydraulic valve blocks, electromagnetic directional proportional valves, hydraulic cylinders, and electrical control system, will operate automatically.

[0021] Lifting device: The system is driven by a double-drum lifting winch 81. This winch is the primary means of lowering and retrieving the jacking pipe. The winch pulls two wire ropes 83 via a series of pulleys to connect the lifting and securing mechanical loads.

[0022] Wave compensation mechanism: Active compensation is achieved through the interaction between the AHC hydraulic cylinder 84 and the movable pulley block 82.

[0023] The AHC hydraulic cylinder 84 is controlled by the AHC hydraulic power unit 90 and supported by the accumulator 89, which stores hydraulic energy to achieve rapid response.

[0024] As the vessel rises and falls, the AHC hydraulic cylinder 84 contracts or extends to release or retract the wire rope in accordance with the frequency of the waves, keeping the downpipe 88 stationary relative to the seabed.

[0025] The movable pulley block 82 moves along the dedicated guide rail 85, ensuring the stability of the wire rope 83's geometry. The tube jack frame and universal joint 87 support the telescopic tube 88. The universal joint bracket keeps the tube vertical as the hull rolls or pitches. The telescopic tube 88 can extend and retract to reach a specific depth.

[0026] The guide wheel 86 is positioned to ensure that the wire rope 83 smoothly enters the carriage assembly, avoids friction and wear, and maintains alignment with the vertical axis of the telescopic section.

[0027] System Operation: During operation, the AHC hydraulic power unit 90 receives data from the PLC control system and the motion reference unit (MRU). When waves cause the vessel to rise and fall, the AHC hydraulic cylinder 84 adjusts the position of the moving pulley block 82 along the guide rail 85. This adjustment changes the effective length of the wire rope 83, thereby counteracting the vertical displacement of the vessel. Therefore, the jacking frame 87 and the telescopic tube 88 are maintained at a constant height above the target point.

[0028] Figure 2 The hydraulic system design and manufacturing shown for the AHC system uses a combination of a standard two-chamber hydraulic cylinder (replacing the commonly used three-chamber hydraulic cylinder), a logic control valve (integrated valve block), a directional proportional valve, a high-pressure accumulator, a low-pressure accumulator, and a hydraulic power unit (HPU).

[0029] 1. System Overview This invention relates to a hybrid wave compensation system capable of operating in both passive wave compensation (PHC) and active wave compensation (AHC) modes. The system utilizes a hydraulic circuit to control the displacement of a hydraulic cylinder 22, which is mechanically connected to a pipe-falling assembly. The system is characterized by its ability to operate in an energy-efficient passive mode for low sea states and a precise sensor-driven active mode for high sea states.

[0030] 2. Main hydraulic components refer to Figure 2 The hydraulic diagram in the image shows the system comprising: i. Power: Motor 24 drives piston pump 23 to draw hydraulic oil from oil tank 1. The oil level is regulated through return oil filter 5.1, air filter 4 and air cooler 6.

[0031] ii. Pressure regulation: High and low pressure thresholds are managed by a bladder accumulator 20, 21. Safety is ensured by direct-acting pressure relief valves 12.1, 12.2.

[0032] iii. Control logic: A series of 3 / 2 direction control valves 15.1–15.4 serve as pilot valves for slide-in spring valves 18.1–18.3, 19 and their corresponding cover plates.

[0033] iv. Precision control: The proportional flow control valve 14 (S4 for short) controls the flow rate, while the directional control valve 13 directs the fluid to achieve active movement of the cylinder.

[0034] 3. Operating Mode A. Passive Wave Compensation (PHC) Mode PHC mode is used for low to moderate sea states (typically with wave heights below one meter). In this mode, the system acts as a hydraulic spring, absorbing the movement of the container through the compressibility of gas in the accumulator, without the need for continuous pump intervention.

[0035] i. Logic state: Valve SV4 (including 15.2, 16.1, 18.1) is set to open.

[0036] ii. Function: This function enables the control valve assembly to be used in conjunction with the high-voltage accumulator 20 and the low-voltage accumulator 21.

[0037] iii. Flow regulation: The proportional flow control valve 14 can be switched to regulate the flow rate generated by the high-voltage accumulator and the cylinder speed, thereby providing adjustable damping.

[0038] B. Active Wave Compensation (AHC) Mode In AHC mode, the system dynamically responds to the motion reference unit (MRU). The PLC (Programmable Logic Controller) executes commands from the hydraulic valve block in real time.

[0039] 1. Hydraulic cylinder extends: i. Main valve: S1 and SV1 are activated (open).

[0040] ii. Flow control: SV4, SV5 and SV6 are activated to control the flow of liquid.

[0041] iii. Speed / Pressure Protection: If the cylinder speed exceeds the safety limit or a pressure peak occurs, SV3 15.1, 17, and 19 will be temporarily activated. By connecting the piston chamber and piston rod chamber, a "regeneration" or "bypass" state is formed to balance the pressure until normal parameters are restored.

[0042] iv. Pressure control: When the low-pressure accumulator reaches its upper limit, SV6 is triggered by a command from pressure sensor PT4.

[0043] 3. Hydraulic cylinder retraction: i. Main valves: S1, SV2, and SV6 are activated (open). ii. Accumulator Regulation: SV4 and SV5 operate in the switching sequence of the PT3 pressure sensor. When the high-voltage accumulator reaches its upper limit, SV4 is turned off and SV5 is turned on to redirect flow and protect system integrity.

[0044] iii. Safety Bypass: Similar to the extension, SV3 can still briefly connect the hydraulic cylinder chamber in the event of overspeed or overpressure.

[0045] 4. Security and Feedback Mechanism The system integrates the comprehensive monitoring of level sensor 2 and temperature sensor 3 to ensure that the hydraulic oil is maintained within the specified operating range. Winner flow control valves 9.1, 9.2, and 10 are used to fine-tune the guiding logic response, while two-way switching valves 11.1 and 11.2 prevent the telescopic pipe from drifting unexpectedly when the system is powered off.

[0046] 5. Technological Advantages i. The designed hydraulic system uses a standard two-chamber hydraulic cylinder (instead of the more common three-chamber hydraulic cylinder). ii. Dual-mode efficiency: By providing a PHC mode, the system reduces wear on the piston pump 23 and lowers energy consumption in calm weather.

[0047] iii. Rapid response: Integrating airbag accumulators 20 and 21 near the control valves ensures immediate hydraulic “rigidity” or “compliance” as required by the MRU.

[0048] iv. Pressure shock protection: SV3’s automatic logic provides fail-safe protection against mechanical shocks caused by rapid hull movement.

[0049] Figure 3 The user interface for controlling the wave compensation system is shown.

[0050] The benefits of this design include increased operating window: the AHC system extends the operating window in inclement weather, improving safety and efficiency; reduced costs: by improving operational efficiency and reducing downtime; these systems help save costs; precision and control: ensures accurate placement of components, reducing rework and operating costs.

Claims

1. A wave compensation system for marine engineering construction, characterized in that, include: At least one dual-chamber hydraulic cylinder (22) configured to drive a telescopic drop pipe; The hydraulic power unit consists of an electric motor (24) and a hydraulic pump (23); At least one high-pressure accumulator (20) and at least one low-pressure accumulator (21) are fluidly connected to the hydraulic cylinder; A logic control valve block, consisting of multiple directional control valves and a proportional flow control valve (14); and A control system consisting of a motion reference unit and a programmable logic controller is configured to drive the valve block in response to the motion of the ship.

2. The wave compensation system according to claim 1, characterized in that, The programmable logic controller is configured to perform manual or automatic selective switching between the following: A passive wave compensation mode is applicable when the sea wave height is below a predetermined threshold, enabling autonomous compensation by high-pressure and low-pressure accumulators; and In higher sea states, an active wave compensation mode is adopted, in which the hydraulic power unit and logic control valve block drive the hydraulic cylinder according to the command of the motion reference unit.

3. The wave compensation system according to claim 1, characterized in that, The logic control valve block includes a bypass valve SV3, which is configured to momentarily connect the piston chamber and piston rod chamber of the hydraulic cylinder (22) when the sensed hydraulic cylinder speed or pressure exceeds a predetermined safety threshold.

4. The wave compensation system according to claim 1, characterized in that, The logic control valve block further includes: The first pilot-operated cartridge valve, SV4, is configured to regulate the flow of hydraulic oil between the high-pressure accumulator and the hydraulic cylinder; and The second pilot cartridge valve SV6 is configured to activate when the low-pressure accumulator (21) reaches a specific pressure limit.

5. The wave compensation system according to claim 1, characterized in that, include: A double-drum hoisting winch (1) is driven by an AC asynchronous variable frequency motor through a gearbox; The motor is equipped with variable speed control, which can adjust the winch speed according to the wave speed; and A movable pulley block (2) is guided by a rigid mechanical linear guide (5) and driven by a hydraulic cylinder (22), wherein the hydraulic cylinder is controlled by a logic control valve block.

6. The wave compensation system according to claim 5, characterized in that, The motor and winch drum employ low-inertia components to facilitate a substantial instantaneous response to the adjusted bulge signal provided by the programmable logic controller.

7. The wave compensation system according to claim 5, characterized in that, The system provides real-time data on wave amplitude, velocity, and acceleration.

8. A wave compensation method using the wave compensation system described in claim 1, characterized in that the steps include... include: The lifting of the ship is measured using a motion reference unit, generating the original lifting signal; The original lifting signal is processed by a programmable logic controller (PLC), and an adjusted lifting signal is output. Drive the proportional flow control valve (14) to regulate the flow of hydraulic oil from the high-pressure accumulator (20) to the hydraulic cylinder (22); and Based on the adjusted lifting signal, the telescopic tube is moved relative to the vessel to maintain a substantially constant distance between the tube and the seabed.

9. The wave compensation method according to claim 8, characterized in that, It further includes a safety regulation step in which the programmable logic controller monitors the pressure via sensor PT3 and closes the first valve SV4 when the high-pressure accumulator reaches its maximum pressure limit, while simultaneously activating the second valve SV5.

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