Deep sea electro-hydraulic valve actuator with redundancy retraction function

Abstract

The application discloses a deep-sea electro-hydraulic valve actuator with redundancy retraction function. The actuator is mainly connected with the manual pressure compression return module and used for the pressure compression return of the first working cavity of the hydraulic cylinder; the manual pressure release compression return module is connected with the valve control retraction module and used for the pressure release compression return of the second working cavity of the hydraulic cylinder; the manual pressure compression return module and the manual pressure release compression return module are both provided with a manual opening valve used for realizing the safe closing of the valve under the deep-sea environment. The two working cavities of the hydraulic cylinder are respectively connected with the parallel redundancy pressure release circuit to realize the safe closing of the valve under the emergency condition, the last forced retraction is realized through the manual opening valve when the structure is blocked and stuck, the influence of the external high-pressure liquid reaction force or the sealing friction blockage is avoided, and it is ensured that the valve can still be reliably triggered and kept flowing under the high external pressure environment. The application considers the stable control and the redundancy safety under the high external pressure and the long-term unattended condition, and meets the requirements of the failure reset and the high reliability of the deep-sea Christmas tree valve actuator.

Description

Technical Field

[0001] This invention relates to a deep-sea electro-hydraulic valve actuator, which relates to the field of fluid transmission and control technology, and specifically to a deep-sea electro-hydraulic valve actuator with redundant retraction function. Background Technology

[0002] Wellheads are core devices in deep-sea oil and gas development, used for controlling wellhead opening and closing, pressure regulation, and safety protection. The valve actuators within these wellheads directly impact the safety and continuity of wellhead operations. As extraction depths increase, traditional actuators relying on remote hydraulic power supply are increasingly showing limitations in response speed, energy consumption, and reliability over long pipeline distances. To address these issues, the application of electro-hydraulic actuators (EHAs) has gradually emerged in recent years. These actuators integrate pumps, valves, cylinders, and drive control systems, resolving the pain points of traditional hydraulic actuators' bulky hydraulic power sources and complex pipelines. They have demonstrated certain advantages in valve control for deepwater and ultra-deepwater wellheads, but also place higher demands on system redundancy and fail-safety.

[0003] Current valve redundancy design mechanisms mainly include: 1. Configuring multiple pump control systems, which can switch to the backup system to drive the hydraulic cylinder to retract when the main system fails; 2. Selecting normally open electrically controlled directional valves, which automatically reset to the open state when power is off to achieve oil circuit depressurization, and working with the spring reset element in the hydraulic cylinder to ensure that the piston automatically retracts after depressurization; 3. Introducing manual operation, where the pressure relief passage is opened by triggering the manual opening valve by the remotely operated vehicle (ROV), further enhancing the safety and redundancy of the system under extreme working conditions.

[0004] However, existing systems often rely on a single path or passive spring reset, which still presents the problem of ineffective shutdown when multiple faults occur concurrently. Therefore, it is necessary to design new redundant circuits to improve reliability. In addition, traditional handle or ring-type manual opening valves are constantly exposed to seawater and are susceptible to the effects of marine organism attachment and sediment accumulation. Therefore, it is necessary to design new manual opening valves to ensure reliable triggering even in the complex environment of the deep sea. Summary of the Invention

[0005] To address the problems existing in the background technology, this invention provides a deep-sea electro-hydraulic valve actuator with redundant retraction function. This invention solves the problem that in existing electro-hydraulic actuators, under failure states such as power interruption, control signal loss, or hydraulic circuit malfunction, the valve may remain in the open position and fail to close in time, thus posing a safety hazard at the wellhead. This invention provides a new valve structure that is not continuously exposed to seawater like traditional handles or rings, thereby effectively reducing the impact of marine organism attachment and sediment accumulation on valve movement; even during long-term operation in the seabed environment, it maintains flexible operation, avoiding the risk of failure due to blockage or accidental contact, and significantly improving the reliability of redundant operation in deep-sea conditions.

[0006] The technical solution adopted in this invention is:

[0007] The deep-sea electro-hydraulic valve actuator with redundant retraction function of the present invention includes:

[0008] The valve module is equipped with a spring-compensated hydraulic cylinder and is used to open and close the main valve pipeline of the wellhead.

[0009] Redundant pump control modules are used to provide power for deep-sea electro-hydraulic valve actuators.

[0010] The valve-controlled retraction module connects to the redundant pump control module and is used for the valve-controlled retraction of the first working chamber of the spring-compensated hydraulic cylinder.

[0011] The manual compression and retraction module is connected to and used for compression and retraction of the first working chamber of the spring-compensated hydraulic cylinder.

[0012] The manual compression and retraction module is connected to and used together with the valve-controlled retraction module to perform compression and retraction of the second working chamber of the spring-compensated hydraulic cylinder; both the manual compression and retraction module and the manual compression and retraction module are equipped with a manual opening valve for safe valve closure in deep-sea environments.

[0013] An integrated valve assembly module is installed and connected between the actuator valve module, redundant pump control module, and valve control retraction module to maintain the normal operation and safety protection of the oil circuit of the deep-sea electro-hydraulic valve actuator.

[0014] The manual compression and retraction module includes a high-pressure accumulator and a first manual opening valve connected in sequence, and a second manual opening valve is provided in the manual compression and retraction module. The inlet and outlet of the first manual opening valve are respectively connected to the high-pressure accumulator and the first working chamber of the spring-compensated hydraulic cylinder. The first manual opening valve is used for manual emergency compression and retraction in deep-sea environments. The inlet and outlet of the second manual opening valve are respectively connected to the second working chamber of the spring-compensated hydraulic cylinder and the valve-controlled retraction module. The second manual opening valve is used for manual emergency compression and retraction in deep-sea environments. The high-pressure accumulator serves as the oil tank of the deep-sea electro-hydraulic valve actuator.

[0015] The manually operated valve includes a pull ring, an unlocking pin, a spring, a valve block, and a valve housing. The pull ring is installed at the center of the end face of the unlocking pin for gripping by the robotic arm of the ROV and for twisting around the central axis of the unlocking pin. A valve stem is located at the center of the side of the unlocking pin away from the pull ring, perpendicular to the central axis of the pull ring. The two ends of the spring are connected to the unlocking pin and the valve block respectively through a spring upper cover and a spring lower cover, and are fitted over the valve stem. When the manually operated valve is closed, the spring is in a compressed state. The valve housing is a hollow shell. The valve stem and spring are fitted into the valve housing from one end, and one end of the valve block is sealed into the valve housing from the other end through a sealing ring. The valve block is connected to the lower cover of the spring, with the other end located outside the valve housing. A groove is provided on the end face of the valve block inside the valve housing, and the end of the valve stem is rotated and engaged in the groove. The valve block has a hollow internal structure, with an oil outlet and an oil inlet on symmetrical sides inside. When closed, these are misaligned and not connected to the oil circuit of the deep-sea electro-hydraulic valve actuator. Two symmetrically arranged locking blocks are provided at the end of the valve stem. When the oil circuit is closed, the end of the valve stem is engaged in the groove via these two locking blocks. After the pull ring rotates, the two locking blocks rotate and disengage from the groove, causing the valve block to leave the valve housing under the spring force until the oil outlet and oil inlet connect with the oil circuit of the deep-sea electro-hydraulic valve actuator, entering the oil circuit open state.

[0016] The manually operated valve also includes a valve block buffer pad, which is located at the center of the valve block. The valve block has a connecting slot and a connecting hole coaxial with the valve stem. One end of the valve block buffer pad is located in the connecting hole and connected to the end face of the valve stem. The other end of the valve block buffer pad is connected to the inner wall of the valve block. The valve block buffer pad is a variable diameter block, and the cross-sectional dimension of the other end of the valve block buffer pad is larger than the dimension of the connecting hole, so as to achieve buffering during the movement of the valve block.

[0017] The integrated valve module includes a first two-way switching valve, a second two-way switching valve, a first relief valve, a second relief valve, a flow matching valve for oil return, and a first check valve and a second check valve for oil replenishment. The first two-way switching valve and the second two-way switching valve are respectively connected to the first working chamber and the second working chamber of the spring-compensated hydraulic cylinder, and both are connected to the redundant pump control module. The oil inlets of the first relief valve and the second relief valve are respectively connected to the first working chamber and the second working chamber of the spring-compensated hydraulic cylinder. The oil outlets of the first relief valve and the second relief valve merge and are connected to the T-port of the flow matching valve and the valve control retraction module. The other two oil ports of the flow matching valve are connected to the redundant pump control module and are arranged in parallel with the oil supply lines of the two working chambers of the spring-compensated hydraulic cylinder. The oil inlets of the first check valve and the second check valve are respectively connected to the first working chamber and the second working chamber of the spring-compensated hydraulic cylinder, and the oil outlets of the first check valve and the second check valve are respectively connected to the redundant pump control module.

[0018] The redundant pump control module includes a first plunger pump, a second plunger pump, a first motor, and a second motor. The first motor drives the first plunger pump as the main power source, and the second motor drives the second plunger pump as an auxiliary power source. The second motor works in parallel with the first plunger pump when the first plunger pump fails or when there is a peak demand for the deep-sea electro-hydraulic valve actuator. The oil inlets of the first and second plunger pumps are connected to the first oil port of the second two-way switching valve and the flow matching valve, and the oil outlet of the first check valve. The oil outlets of the first and second plunger pumps are connected to the second oil port of the first two-way switching valve and the flow matching valve, and the oil outlet of the second check valve.

[0019] The valve-controlled retraction module includes a third two-way switching valve and a pressure compensator. The second working chamber of the spring-compensated hydraulic cylinder is connected in parallel with the third two-way switching valve and the second manual opening valve of the manual pressure relief retraction module. The oil outlet of the second manual opening valve is connected to the pressure compensator. The oil outlets of the first relief valve and the second relief valve merge and are connected to the pressure compensator. The pressure compensator serves as the oil tank of the deep-sea electro-hydraulic valve actuator.

[0020] The valve module also includes a switch valve block. The hydraulic cylinder in the first working chamber of the spring-compensated hydraulic cylinder is connected to the main valve pipeline of the tree through the switch valve block. The initial state of the switch valve block is closed. When the deep-sea electro-hydraulic valve actuator extends, it pushes the switch valve block to the open state.

[0021] The valve control method of the deep-sea electro-hydraulic valve actuator with redundant retraction function of the present invention includes:

[0022] The deep-sea electro-hydraulic valve actuator is divided into four types of retraction circuits during valve control: redundant pump control circuit, valve control retraction circuit, manual compression retraction circuit, and manual decompression retraction circuit. When the deep-sea electro-hydraulic valve actuator is in normal working state, the main valve pipeline of the production tree is in the open state, the two-way switch valves (6, 7, 8) are closed, and the manual opening valve is closed.

[0023] In the conventional pump control circuit, the first motor drives the first plunger pump to supply oil to the spring-compensated hydraulic cylinder, and the second motor drives the second plunger pump as a redundant power source. The first plunger pump, the first motor, the second plunger pump, and the second motor all serve as power components. When one set of power components fails, the other set of power components takes over the oil supply function. When an output higher than the preset flow rate is required, the first plunger pump and the second plunger pump work in parallel. Through the connection of the first two-way switch valve and the second two-way switch valve, the pressure supply and oil return to the two working chambers of the spring-compensated hydraulic cylinder are realized to ensure the stable retraction of the piston rod.

[0024] In the aforementioned electrically controlled retraction circuit, the pressure compensator performs oil recovery and compensation. The third two-way switch valve is connected to the second working chamber of the spring-compensated hydraulic cylinder. When the third two-way switch valve is driven to open, the oil in the second working chamber of the spring-compensated hydraulic cylinder returns through the pressure compensator, forming a pressure relief passage. During this process, the spring reset mechanism in the spring-compensated hydraulic cylinder applies force in the retraction direction, pushing the piston rod to retract, thereby closing the deep-sea electro-hydraulic valve actuator.

[0025] In the manual pressure relief return circuit, the second manual opening valve is connected in parallel between the second working chamber of the spring-compensated hydraulic cylinder and the pressure compensator. When the second manual opening valve is opened under the operation of the unmanned remotely operated vehicle (ROV), the oil in the second working chamber is discharged through the pressure compensator to eliminate the residual pressure in the chamber. At this time, the spring reset mechanism in the spring-compensated hydraulic cylinder immediately takes effect, pushing the piston rod back to the initial position.

[0026] In the manual compression return circuit, the high-pressure accumulator is connected to the first working chamber of the spring-compensated hydraulic cylinder via an oil pipe and is in a pre-charged state under normal conditions. When the ROV operates the first manual opening valve, the oil outlet and oil inlet of the first manual opening valve are switched to the connected position, and the high-pressure oil stored in the high-pressure accumulator directly enters the first working chamber of the spring-compensated hydraulic cylinder, pushing the piston rod to move in the retraction direction to achieve forced retraction.

[0027] This invention proposes four redundant retraction methods for deep-sea electro-hydraulic valve actuators. These include two externally driven redundant retraction functions: one where a dual-way manual opening valve releases high pressure from an accumulator to the first and second working chambers respectively, thereby retracting the hydraulic cylinder and closing the actuator; and two self-driven redundant retraction functions: redundant pump control and valve control operation. The redundant pump control function uses multiple sets of pump control equipment to retract the hydraulic cylinder even if one set fails. The valve control operation redundant retraction function uses a two-way valve to release pressure in the second working chamber of the hydraulic cylinder, thus retracting the cylinder and closing the actuator. Overall, this improves the system's redundancy and reliability.

[0028] This invention's manually operated valve adopts a twist-unlock + spring-driven structural design, which differs from the commonly used manual ball valves or continuous holding opening methods on land. It can adapt to the high pressure and low visibility environment of the deep sea. At the same time, manual operation is impossible in the high pressure environment of the deep sea, and engineering requires the use of unmanned remotely operated vehicles (ROVs) for manual operation. However, most manual valves on the market are operated by rotating handles and levers, most of which are difficult to operate in the deep sea environment. For example, the rotating handle structure is not easy to operate by the ROV robotic arm, and the lever is easily affected by marine life. The pull ring structure of this invention ensures that the ROV robotic arm can easily exert force and move quickly during operation, thereby reducing the difficulty of operation in the deep sea environment.

[0029] The beneficial effects of this invention are:

[0030] 1. This invention proposes a deep-sea electro-hydraulic valve actuator with redundant retraction function and four retraction methods: conventional pump control circuit, electrically controlled retraction circuit, manual decompression retraction circuit, and manual compression retraction circuit. Retraction can be achieved using conventional oil supply from dual motors and dual pumps, or forced retraction can be achieved through pressure relief via electrically controlled valves, manual valve decompression, or manual accumulator pressurization in the event of main power supply failure, significantly improving system redundancy and failure safety. In the electrically controlled retraction circuit, the third two-way switching valve and the deep-sea compensator form an independent pressure relief channel, which, together with the spring reset mechanism built into the hydraulic cylinder, ensures that the actuator can automatically retract in the event of main oil supply interruption. In the manual decompression and manual pressurization circuits, rapid decompression retraction and forced compression retraction are achieved respectively through the operation of dedicated manual opening valves, thus providing final protection under mechanical triggering.

[0031] 2. The manual opening valve of this invention adopts a twist unlocking + spring drive structure, which is different from the rotary handle or lever operation commonly used on land. It avoids the problems of jamming and accidental activation caused by marine organisms attaching, silt deposition or external collisions. Its pull ring type operating component is optimized for the gripping of the robotic arm of the remotely operated vehicle (ROV). It has the advantages of simple operation, rapid action and reliable triggering. It can achieve a stable redundant pressure relief channel in the low visibility and high external pressure environment of the deep sea, which greatly improves the maintainability of the actuator and the adaptability of the deep sea environment.

[0032] 3. The spring reset mechanism inside the hydraulic cylinder of this invention, in conjunction with multiple circuits, ensures that the piston rod can retract to a safe position in the event of failure of any single component, realizing the design concept of "failure equals safety" and significantly improving the safety redundancy level of deep-sea operations. The two working chambers of the hydraulic cylinder are respectively connected in parallel to a manual opening valve and a two-way switching valve, ensuring that even if one chamber circuit fails, compression can still be achieved through the other circuit, fundamentally eliminating the risk of piston rod locking due to single-chamber failure.

[0033] 4. Under different retraction strategies, the present invention uses "retraction to close the valve" as the only final state, and there will be no intermediate position lock-up or erroneous action, which ensures the predictability and safety of the system failure mode and improves the overall reliability. Attached Figure Description

[0034] Figure 1 This is a hydraulic schematic diagram of the present invention;

[0035] Figure 2 This is a simplified structural diagram of the manually operated valve of the present invention;

[0036] Figure 3 This is a schematic diagram of the installation configuration of the valve actuator of the present invention on the tree trunk;

[0037] Figure 4 This is a flow-pressure differential characteristic diagram of the manually operated valve of the present invention;

[0038] Figure 5 This is a stroke-flow characteristic diagram of the manually operated valve of the present invention;

[0039] In the diagram: 1. Main valve pipeline of the production tree; 2. Switch valve block; 3. High-pressure accumulator; 4. First manual opening valve; 4.1. Pull ring; 4.2. Unlocking pin; 4.3. Spring upper cover; 4.4. Spring; 4.5. Spring lower cover; 4.6. Valve block; 4.7. Valve block buffer pad; 4.8. Oil outlet; 4.9. Oil inlet; 4.10. Sealing ring; 4.11. Valve housing; 4.12. Valve stem; 5. Second manual opening valve; 6. First two-way switch valve; 7. Second two-way switch valve; 8. Third two-way switch valve; 9. First relief valve; 10. Second relief valve; 11. Flow matching valve; 12. Pressure compensator; 13. First plunger pump; 14. Second plunger pump; 15. Spring-compensated hydraulic cylinder; 16. First motor; 17. Second motor; 18. First check valve; 19. Second check valve. Detailed Implementation

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] like Figure 1As shown, the deep-sea electro-hydraulic valve actuator with redundant retraction function of the present invention includes a pump control section consisting of a first motor 16, a second motor 17, a first plunger pump 13, a second plunger pump 14, a first two-way switching valve 6, and a second two-way switching valve 7; a manual / emergency circuit consisting of a first manual opening valve 4, a second manual opening valve 5, a third two-way switching valve 8, and a high-pressure accumulator 3; and a compensation and pressure relief circuit consisting of a pressure compensator 12, a flow matching valve 11, and dual relief valves 9 and 10. All modules are connected through an integrated valve block to form a complete oil circuit. The deep-sea electro-hydraulic valve actuator with redundant retraction function is specifically divided into an actuator valve module, a redundant pump control module, a valve-controlled retraction module, a manual compression and retraction module, a manual decompression and retraction module, and an integrated valve group module. The actuator valve module is equipped with a spring-compensated hydraulic cylinder 15 and is used for opening and closing the main valve pipeline 1 of the production tree. The redundant pump control module provides power to the deep-sea electro-hydraulic valve actuator. The valve-controlled retraction module is connected to the redundant pump control module and is used for the valve-controlled retraction of the first working chamber of the spring-compensated hydraulic cylinder 15. The manual compression and retraction module is connected to and is used for the compression and retraction of the first working chamber of the spring-compensated hydraulic cylinder 15. The manual decompression and retraction module is connected to and is used together with the valve-controlled retraction module for the decompression and retraction of the second working chamber of the spring-compensated hydraulic cylinder 15. Both the manual compression and retraction module and the manual decompression and retraction module are equipped with manual opening valves 4 and 5 for achieving safe valve closure in deep-sea environments. The integrated valve group module is installed and connected between the actuator valve module, the redundant pump control module, and the valve-controlled retraction module to maintain the normal operation and safety protection of the oil circuit of the deep-sea electro-hydraulic valve actuator.

[0042] The valve actuator module also includes a switch valve block 2. The hydraulic cylinder in the first working chamber of the spring-compensated hydraulic cylinder 15 is connected to the main valve pipeline 1 of the production tree via the switch valve block 2. The switch valve block 2 is initially in the closed state. When the deep-sea electro-hydraulic valve actuator extends, it pushes the switch valve block 2 to the open state. The spring-compensated hydraulic cylinder 15 is equipped with a spring reset mechanism, which provides retraction force when the spring-compensated hydraulic cylinder 15 is in the extended state. The two end chambers of the spring-compensated hydraulic cylinder 15 are respectively connected in parallel to a manual compression and retraction module and a manual decompression and retraction module. The gate is forcibly closed by manually opening valves 4 and 5 to depressurize the second working chamber and pressurize the first working chamber. It is also connected in parallel to a two-way switch valve 8 for valve-controlled retraction, which is used to ensure reliable piston retraction in the event of failure of the main control system.

[0043] The manual compression and retraction module includes a high-pressure accumulator 3 and a first manual opening valve 4 connected in sequence. The high-pressure accumulator 3 can specifically use a high pressure higher than 60 MPa. The manual compression and retraction module is equipped with a second manual opening valve 5. The oil inlet 4.9 and oil outlet 4.8 of the first manual opening valve 4 are respectively connected to the high-pressure accumulator 3 and the first working chamber of the spring-compensated hydraulic cylinder 15. The first manual opening valve 4 is used for manual emergency compression and retraction in deep-sea environments. The oil inlet 4.9 and oil outlet 4.8 of the second manual opening valve 5 are respectively connected to the second working chamber of the spring-compensated hydraulic cylinder 15 and the valve-controlled retraction module. The second manual opening valve 5 is used for manual emergency compression and retraction in deep-sea environments. The high-pressure accumulator 3 serves as the oil tank for the deep-sea electro-hydraulic valve actuator. The high-pressure accumulator 3 is connected to the oil replenishment port of the bidirectional plunger pumps 13 and 14 through the flow matching valve 11. It is used to provide oil replenishment when the system pressure is low or the energy is insufficient, so as to maintain the system pressure balance and oil circulation, and the overall pressure of the hydraulic system increases with the water depth.

[0044] like Figure 2 As shown, the manually operated valves 4 and 5 include a pull ring 4.1, an unlocking pin 4.2, a spring 4.4, a valve block 4.6, and a valve housing 4.11. The pull ring 4.1 is installed at the center of the end face of the unlocking pin 4.2 so that the robotic arm of the remotely operated vehicle (ROV) can grip it and perform a torsion operation around the central axis of the unlocking pin 4.2. The pull ring 4.1 is used to transmit external torque to the valve stem 4.12. The valve stem 4.12 is located at the center of the side of the unlocking pin 4.2 away from the pull ring 4.1. Perpendicular to the central axis of pull ring 4.1, the two ends of spring 4.4 are connected to unlocking pin 4.2 and valve block 4.6 respectively through upper spring cover 4.3 and lower spring cover 4.5, and are fitted onto the outside of valve stem 4.12. When valves 4 and 5 are manually opened, spring 4.4 is in a compressed state when closed. Valve housing 4.11 is a hollow shell. Valve stem 4.12 and spring 4.4 are fitted into valve housing 4.11 from one end of valve housing 4.11, and valve block 4.6 is fitted into valve housing 4.11 from one end of valve housing 4.11. The other end of valve block 4.11 is sealed within valve housing 4.11 via sealing ring 4.10, and its end face is connected to spring cover 4.5. The other end of valve block 4.6 is located outside valve housing 4.11. A groove is provided on the end face of valve block 4.6 within valve housing 4.11, and the end of valve stem 4.12 is rotatably engaged in the groove. The interior of valve block 4.6 is hollow, and oil outlet 4.8 and oil inlet 4.9 are symmetrically located on both sides of the interior of valve block 4.6, and when closed, they connect with the deep... The oil circuit of the deep-sea electro-hydraulic valve actuator is misaligned and disconnected; the end of the valve stem 4.12 is provided with two locking blocks symmetrically along the radial direction. When the oil circuit is closed, the end of the valve stem 4.12 is locked in the slot by the two locking blocks. After the pull ring 4.1 rotates, the two locking blocks rotate and disengage from the slot, so that the valve block 4.6 leaves the valve housing 4.11 under the elastic force of the spring 4.4 until the oil outlet 4.8 and oil inlet 4.9 are connected to the oil circuit of the deep-sea electro-hydraulic valve actuator and enter the oil circuit open state.

[0045] The manually operated valves 4 and 5 also include a valve block buffer pad 4.7. The valve block buffer pad 4.7 is located at the internal center of the valve block 4.6. The valve block 4.6 has a connecting slot and a connecting hole coaxial with the valve stem 4.12. One end of the valve block buffer pad 4.7 is located in the connecting hole and connected to the end face of the valve stem 4.12. The other end of the valve block buffer pad 4.7 is connected to the internal wall of the valve block 4.6. The valve block buffer pad 4.7 is a variable diameter block. The cross-sectional dimension of the other end of the valve block buffer pad 4.7 is larger than the dimension of the connecting hole to achieve buffering during the movement of the valve block 4.6.

[0046] like Figure 3 As shown, the valve actuator is installed on the valve of the wellhead via a flange connection. The actuator is connected to the wellhead's hydraulic system via hydraulic lines and is used to control the opening and closing of the valve. The actuator is equipped with a manual unlocking device for manually opening or closing the valve via an unmanned remotely operated vehicle (ROV) or manual operation in the event of an automatic control system failure. The connection between the actuator and the valve is via flanges to ensure mechanical fixation and hydraulic sealing between them. The hydraulic lines are connected to external systems through dedicated interfaces to ensure the accuracy of fluid control. The flow channels inside the valve body are connected to the wellhead piping to achieve fluid control and regulation. The valve actuator automatically controls the opening and closing of the valve by receiving commands from the control system, and can be manually operated via the manual unlocking device in the event of power or control system failure, ensuring the operational safety of the wellhead.

[0047] The integrated valve group module includes a first two-way switching valve 6, a second two-way switching valve 7, a first relief valve 9, a second relief valve 10 for hydraulic pressure control, a flow matching valve 11 for oil return, and a first check valve 18 and a second check valve 19 for oil replenishment. The first two-way switching valve 6 and the second two-way switching valve 7 are respectively connected to the first working chamber and the second working chamber of the spring-compensated hydraulic cylinder 15, and both are connected to the redundant pump control module. The oil inlets of the first relief valve 9 and the second relief valve 10 are respectively connected to the first working chamber and the second working chamber of the spring-compensated hydraulic cylinder 15. The oil outlet of flow valve 10 is connected to the T-port of flow matching valve 11 and the valve control retraction module to ensure timely pressure relief of the system under abnormal high pressure. The other two oil ports of flow matching valve 11 are connected to redundant pump control module and arranged in parallel with the oil supply lines of the two working chambers of spring-compensated hydraulic cylinder 15 to achieve flow balance and stable control under working condition switching. The oil inlets of the first check valve 18 and the second check valve 19 are respectively connected to the first working chamber and the second working chamber of spring-compensated hydraulic cylinder 15, and the oil outlets of the first check valve 18 and the second check valve 19 are respectively connected to redundant pump control module. Two two-way switching valves 6 and 7 are installed at intervals on one side of the integrated valve block, and flow matching valve 11 and two relief valves 9 and 10 are installed at intervals on the other side of the integrated valve block. All valve groups are immersed in oil, and check valves 18 and 19 replenish oil when spring-compensated hydraulic cylinder 15 is activated.

[0048] The redundant pump control module includes a first plunger pump 13, a second plunger pump 14, a first motor 16, and a second motor 17. The first motor 16 drives the first plunger pump 13 as the main power source, providing the main flow and pressure of the actuator under normal operating conditions. The second motor 17 drives the second plunger pump 14 as an auxiliary power source, working in parallel with the first plunger pump 13 when the first plunger pump 13 fails or when the deep-sea electro-hydraulic valve actuator has peak demand, to ensure redundant oil supply and flow compensation for the actuator. The oil inlets of the first plunger pump 13 and the second plunger pump 14 are connected to the first oil port of the second two-way switch valve 7, the flow matching valve 11, and the oil outlet of the first check valve 18. The oil outlets of the first plunger pump 13 and the second plunger pump 14 are connected to the second oil port of the first two-way switch valve 6, the flow matching valve 11, and the oil outlet of the second check valve 19.

[0049] The valve-controlled retraction module includes a third two-way switching valve 8 and a pressure compensator 12. The second working chamber of the spring-compensated hydraulic cylinder 15 is connected in parallel to the third two-way switching valve 8 and the second manual opening valve 5 of the manual pressure relief retraction module. The oil outlet 4.8 of the second manual opening valve 5 is connected to the pressure compensator 12. The oil outlets of the first relief valve 9 and the second relief valve 10 are merged and connected to the pressure compensator 12. The pressure compensator 12 serves as the oil tank of the deep-sea electro-hydraulic valve actuator and is used to control the system oil pressure and the pressure balance of the external seawater.

[0050] The deep-sea electro-hydraulic valve actuator with redundant retraction function of the present invention includes the following operating conditions:

[0051] Start-up and standby conditions: When the system is powered on, the first motor 16 and the second motor 17 are in standby mode. The first and second two-way switching valves 6 and 7 remain closed to isolate the actuator cylinder, the third two-way switching valve 8 is closed to isolate the pressure compensator 12, and the overflow valves 9 and 10 are in pressure-limiting standby mode. At this time, the flow matching valve 11 establishes back pressure to ensure stable oil filling in the pipeline and prevent cavitation.

[0052] In normal pump-controlled retraction mode: motors 16 and 17 drive plunger pumps 13 and 14 to supply oil to the designated chamber of spring-compensated hydraulic cylinder 15. The first and second two-way switching valves 6 and 7 are opened according to the command, and the other chamber is depressurized through the return oil circuit, thereby pushing the piston rod to retract. When one set of power components fails, it can be switched to the other set of power components to continue working. When a large flow rate is required for rapid start-up, the two plunger pumps 13 and 14 supply oil in parallel to ensure stable retraction.

[0053] In normal pump-controlled extension operation: When the piston rod of the spring-compensated hydraulic cylinder 15 needs to extend, the control module drives the first motor 16 or the second motor 17 to drive the plunger pumps 13 and 14 to supply oil. The first and second two-way switching valves 6 and 7 are opened according to the command, so that the first working chamber flows back through the return oil circuit, thereby pushing the piston rod to move in the extension direction. When one set of power components fails, it can be switched to the other set of power components to continue working. When a large flow rate is required for rapid start-up, the two plunger pumps 13 and 14 supply oil in parallel to ensure stable retraction.

[0054] Electrically controlled retraction mode: When the first plunger pump 13 fails or the signal is abnormal, the control module drives the third two-way switch valve 8 to open, closes the second two-way switch valve 7, and opens the first two-way switch valve 6. The second working chamber of the spring-compensated hydraulic cylinder 15 forms a return oil channel through the pressure compensator 12, and the pressure in the chamber is released quickly. In conjunction with the spring reset mechanism in the spring-compensated hydraulic cylinder 15, the piston rod is pushed to retract, thereby closing the actuator.

[0055] Manual pressure relief and return operation: In the event of a complete electrical failure, the ROV operates the second manual opening valve 5, which connects the second working chamber of the spring-compensated hydraulic cylinder 15 to the pressure compensator 12. The residual pressure in the chamber is released through the return oil circuit, and the piston rod retracts under the action of the spring.

[0056] Manual compression and retraction mode: When both the main control and pump control fail and the actuator cylinder is stuck, the ROV operates the first manual opening valve 4, and the high-pressure oil stored in the high-pressure accumulator 3 is injected into the first working chamber of the spring-compensated hydraulic cylinder 15, pushing the piston rod to retract forcibly, so as to achieve safe valve closure.

[0057] Compensation and protection circuit: Pressure compensator 12 makes the total system pressure change synchronously with water depth to ensure stability at different depths; flow matching valve 11 establishes constant back pressure, improves the switching stability of valve block 4.6 and prevents cavitation; relief valves 9 and 10 provide overpressure protection for the spring-compensated hydraulic cylinder 15 and high-pressure accumulator 3 to avoid damage from external load impacts.

[0058] The valve control method of the deep-sea electro-hydraulic valve actuator with redundant retraction function of the present invention is as follows:

[0059] The deep-sea electro-hydraulic valve actuator is divided into four types of retraction circuits during valve control: redundant pump control circuit, valve control retraction circuit, manual compression retraction circuit, and manual decompression retraction circuit. When the deep-sea electro-hydraulic valve actuator is in normal working condition, the main valve pipeline 1 of the production tree is in the open state, the two-way switch valves 6, 7, and 8 are closed, and the manual opening valves 4 and 5 are closed.

[0060] In a conventional pump control circuit, the first motor 16 drives the first plunger pump 13 to supply oil to the spring-compensated hydraulic cylinder 15, and the second motor 17 drives the second plunger pump 14 as a redundant power source. The first plunger pump 13, the first motor 16, the second plunger pump 14, and the second motor 17 all serve as power components. When one set of power components fails, the other set of power components takes over the oil supply function. When an output higher than the preset flow rate is required, the first plunger pump 13 and the second plunger pump 14 work in parallel. Through the connection of the first two-way switching valve 6 and the second two-way switching valve 7, the pressure supply and oil return to the two working chambers of the spring-compensated hydraulic cylinder 15 are realized to ensure the stable retraction of the piston rod. The conventional pump control circuit, through the dual-pump parallel connection and mutual backup structure design, realizes the integration of conventional drive and redundant drive, improving the reliability and redundancy safety of the hydraulic circuit.

[0061] Under normal operating conditions, the conventional pump control circuit uses the first motor 16 to drive the first plunger pump 13 to provide working pressure to the spring-compensated hydraulic cylinder 15. This, combined with the opening of the second two-way switching valve 7 and the first two-way switching valve 6, enables the piston rod to retract normally. Additionally, if one power unit fails, another power unit can be activated for redundant control. Furthermore, when the load is large or the first plunger pump 13 cannot meet the flow requirements alone, the second motor 17 drives the second plunger pump 14 to supply oil in parallel, ensuring the stable retraction of the spring-compensated hydraulic cylinder 15 and the reliable closure of the valves, thus improving the reliability and redundancy safety of the hydraulic circuit.

[0062] In the electrically controlled retraction circuit, the pressure compensator 12 performs oil recovery and compensation. The third two-way switch valve 8 is connected to the second working chamber of the spring-compensated hydraulic cylinder 15. When the third two-way switch valve 8 is driven to open, the oil in the second working chamber of the spring-compensated hydraulic cylinder 15 returns through the pressure compensator 12, forming a pressure relief passage. During this process, the spring reset mechanism in the spring-compensated hydraulic cylinder 15 applies force in the retraction direction, pushing the piston rod to retract, thereby closing the deep-sea electro-hydraulic valve actuator. The electrically controlled retraction circuit utilizes the third two-way switch valve 8 and the spring-compensated hydraulic cylinder 15 to form an independent pressure relief and reset channel, providing a reliable electrically controlled retraction function when the main oil supply is interrupted.

[0063] The electrically controlled retraction circuit is mainly used in the case of motor failure. The pressure compensator 12 acts as an oil tank. When the motor drive fails or the main circuit is interrupted, the control module outputs a signal to open the third two-way switch valve 8, so that the second working chamber of the spring-compensated hydraulic cylinder 15 is connected to the return oil channel, and the pressure in the chamber is released quickly. In this state, the spring reset mechanism built into the spring-compensated hydraulic cylinder 15 provides mechanical force in the retraction direction, pushing the piston rod to retract, realizing the automatic closing of the actuator, providing another way to close the valve, and improving the reliability and redundancy safety of the hydraulic circuit.

[0064] In the manual pressure relief return circuit, the second manual opening valve 5 is connected in parallel between the second working chamber of the spring-compensated hydraulic cylinder 15 and the pressure compensator 12. When the second manual opening valve 5 is opened under the operation of the unmanned remotely operated vehicle (ROV), the oil in the second working chamber is discharged through the pressure compensator 12 to eliminate the residual pressure in the chamber. At this time, the spring reset mechanism in the spring-compensated hydraulic cylinder 15 immediately takes effect, pushing the piston rod back to the initial position. The manual pressure relief return circuit avoids electrical control dependence through mechanically triggered pressure relief, ensuring the system's redundant retraction capability under conditions of complete electrical failure.

[0065] The manual pressure relief return circuit is mainly used in situations where the motor or main control fails. The pressure compensator 12 acts as an oil tank in the hydraulic circuit. When the main control fails or electrical communication is lost, the second manual opening valve 5 can be operated by the robotic arm of the ROV to connect the second working chamber of the spring-compensated hydraulic cylinder 15 with the pressure compensator 12, quickly releasing the pressure in the chamber. After the pressure is released, the spring reset mechanism of the spring-compensated hydraulic cylinder 15 immediately takes effect, pushing the piston rod to the retracted end to close the valve.

[0066] In the manual compression return loop, the high-pressure accumulator 3 is connected to the first working chamber of the spring-compensated hydraulic cylinder 15 via an oil pipe and is in a pre-charged state under normal conditions. When the ROV operates the first manual opening valve 4, the oil outlet 4.8 and oil inlet 4.9 of the first manual opening valve 4 switch to the connected position, and the high-pressure oil stored in the high-pressure accumulator 3 directly enters the first working chamber of the spring-compensated hydraulic cylinder 15, pushing the piston rod to move in the retraction direction, thus achieving forced retraction. The manual compression return loop utilizes the high-pressure oil from the high-pressure accumulator 3 as an independent energy supply, realizing mechanical retraction without motor drive, and ensuring the final shut-off action in extreme environments.

[0067] The manual compression return loop is mainly used in situations where the motor fails, the main control fails, or the spring-compensated hydraulic cylinder 15 is stuck. The high-pressure accumulator 3 is pre-charged on shore. When the main control fails and the spring-compensated hydraulic cylinder 15 is in the extended position, the robotic arm of the ROV can operate the first manual opening valve 4 to quickly inject the high-pressure oil stored in the high-pressure accumulator 3 into the first working chamber of the spring-compensated hydraulic cylinder 15. The external high pressure pushes the piston to move in the retraction direction, achieving forced retraction. This method uses the energy stored in the high-pressure accumulator 3 as a redundant power source to ensure that the actuator can still complete the closing action under extreme conditions.

[0068] To verify the working characteristics of this invention under ultra-high pressure underwater conditions, numerical simulation was used to calculate the stroke-flow relationship of the manual spring self-holding valve. The simulation boundary conditions were set as follows: water depth 3000m, ambient pressure approximately 30MPa, ambient temperature approximately 1.5℃; the pressure difference across the valve was taken as a typical operating condition value, for example, pressure difference ΔP = 15MPa. In the simulation, the pressure difference was gradually increased, resulting in the following... Figure 4 The diagram shows the flow rate variation curves of the valve under different pressure differentials. Figure 4 It can be seen that the valve begins to conduct after reaching the cracking pressure, and the flow rate increases nonlinearly with the increase of pressure difference. When the flow channel is close to saturation, it enters the plateau region and exhibits obvious window flow restriction characteristics.

[0069] Based on this, by applying a control signal to trigger the unlocking / return action, the relationship curve between the valve core stroke s and the flow rate Q is obtained, as follows: Figure 5 As shown. Figure 5The solid line represents the Q-s curve of the opening path, and the dashed line represents the Q-s curve of the closing path, with the unlocking point su, reseating point sr, and full-open stroke smax marked. It can be seen that the valve core begins to conduct near the unlocking point, and the flow rate increases approximately monotonically with increasing stroke, entering a plateau region near the full-open stroke. Due to the spring's self-holding mechanism and friction, the reseating point of the closing path is lower than the unlocking point, forming a stable hysteresis band. Under the above boundary conditions, simulation results show that the unlocking stroke is approximately 0.12 mm, the reseating stroke is approximately 0.06 mm, and the maximum flow rate is constrained by both window flow limitation and pressure difference. These results demonstrate that the present invention can still achieve reliable unlocking, stable conduction, and predictable reseating under ultra-high external pressure of 30 MPa and low temperature of 1.5℃, exhibiting good deep-sea underwater performance and consistency.

[0070] This invention proposes multiple redundant shut-off strategies. Traditional spring-assisted, electronically controlled valve-controlled, and redundant pump-controlled systems may fail to properly retract and close due to electronic control failure, pump station shutdown, hydraulic circuit blockage, or signal interruption, leading to safety risks and reliability issues. Existing systems often rely on a single path or passive spring reset, which still cannot achieve effective shut-off when multiple faults occur concurrently. Based on this, a manual shut-off strategy for remotely operated vehicles (ROVs) is proposed. The first and second working chambers of the spring-compensated hydraulic cylinder 15 are connected in parallel with redundant pressure relief circuits. In the event of control failure or power interruption, pressure relief or pressurization is triggered, and the valve reliably retracts under spring assistance, achieving safe valve closure. The system ensures valve opening and closing control via redundant pump control during normal operation; in case of single pump control failure, another pump control system is activated; in case of failure, power outage, or emergency, valves are safely closed via valve control resetting and spring reset; in case of structural blockage or jamming, manual opening of valves 4 and 5 achieves final forced retraction. To achieve this, the manually operated valve designed in this invention features a torsion unlocking + spring-driven self-holding structure. The locking is released by a torsion action performed by an unmanned remotely operated vehicle (ROV), and the valve core is driven by spring force to quickly switch the flow path. After the operation is completed, the valve core automatically remains in the open position, unaffected by external high-pressure liquid reaction force or sealing friction blockage, thus ensuring reliable triggering and maintaining flow even under high external pressure environments. This invention balances stable control and redundant safety under high external pressure and long-term unattended operation conditions, meeting the requirements of deep-sea oil production tree valve actuators for failure reset and high reliability.

[0071] The above embodiments are used to explain and illustrate the present invention, and not to limit it. Any modifications and equivalent substitutions made to the present invention without departing from the spirit and claims should be included within the scope of protection of the present invention.

Claims

1. A deep-sea electro-hydraulic valve actuator with redundant retraction function, characterized in that, Comprise: An execution valve module, provided with a spring compensation hydraulic cylinder (15) and used for opening and blocking of a main valve pipeline (1) of a Christmas tree; A redundant pump control module, used for power supply of a deep-sea electro-hydraulic valve actuator; A valve control retraction module, connected with the redundant pump control module and used for valve control retraction of a first working chamber of the spring compensation hydraulic cylinder (15); A manual pressurization retraction module, connected with and used for pressurization retraction of the first working chamber of the spring compensation hydraulic cylinder (15); A manual pressure relief retraction module, connected with and used for pressure relief retraction of a second working chamber of the spring compensation hydraulic cylinder (15) together with the valve control retraction module; the manual pressurization retraction module and the manual pressure relief retraction module are respectively provided with a first manual opening valve (4) and a second manual opening valve (5) for realizing safe closing of a valve under a deep-sea environment; An integrated valve group module, installed and connected between the execution valve module, the redundant pump control module and the valve control retraction module, and used for maintaining normal operation and safety protection of an oil circuit of the deep-sea electro-hydraulic valve actuator; The first manual opening valve (4) and the second manual opening valve (5) comprise a pull ring (4.1), an unlocking pin (4.2), a spring (4.4), a valve block (4.6) and a valve shell (4.11), the pull ring (4.1) is installed at the center of the end surface of the unlocking pin (4.2) for being clamped by a manipulator of a remotely operated vehicle (ROV) and being twisted around the central axis of the unlocking pin (4.2); the unlocking pin (4.2) is provided with a valve rod (4.12) at the center of the side surface away from the pull ring (4.1), the valve rod (4.12) is perpendicular to the central axis of the pull ring (4.1), the two ends of the spring (4.4) are connected to the unlocking pin (4.2) and the valve block (4.6) through the connected spring upper cover (4.3) and spring lower cover (4.5) and are sleeved outside the valve rod (4.12), the spring (4.4) is in a compressed state in the closed state of the first manual opening valve (4) and the second manual opening valve (5); the valve shell (4.11) is a hollow shell, the valve rod (4.12) and the spring (4.4) are sleeved in the valve shell (4.11) from one end of the valve shell (4.11), one end of the valve block (4.6) is sealed and sleeved in the valve shell (4.11) from the other end of the valve shell (4.11) through a sealing ring (4.10) and is connected to the spring lower cover (4.5) at the end surface, and the other end of the valve block (4.6) is located outside the valve shell (4.11); the end surface of the valve block (4.6) located in the valve shell (4.11) is provided with a clamping groove, and the end of the valve rod (4.12) is rotationally clamped in the clamping groove; the inside of the valve block (4.6) is a hollow structure, and symmetrical two sides of the inside of the valve block (4.6) are provided with an oil outlet (4.8) and an oil inlet (4.9) and are not communicated with the oil circuit of the deep-sea electro-hydraulic valve actuator in the closed state; the end of the valve rod (4.12) is provided with two clamping blocks radially and symmetrically, the end of the valve rod (4.12) is clamped in the clamping groove through the two clamping blocks in the oil circuit closed state, after the pull ring (4.1) is rotated, the two clamping blocks are rotated and separated from the clamping groove, so that the valve block (4.6) leaves the valve shell (4.11) under the elastic force of the spring (4.4) until the oil outlet (4.8) and the oil inlet (4.9) are communicated with the oil circuit of the deep-sea electro-hydraulic valve actuator and enter the oil circuit opening state.

2. The deep-sea electro-hydraulic valve actuator with redundancy retraction function according to claim 1, characterized in that: The manual pressure compression return module comprises a high-pressure accumulator (3) and a first manual opening valve (4) which are sequentially communicated, and a second manual opening valve (5) is arranged in the manual pressure relief compression return module; the oil inlet (4.9) and the oil outlet (4.8) of the first manual opening valve (4) are respectively communicated with the high-pressure accumulator (3) and the first working chamber of the spring compensation hydraulic cylinder (15), and the first manual opening valve (4) is used for manual emergency pressure compression return in a deep-sea environment; the oil inlet (4.9) and the oil outlet (4.8) of the second manual opening valve (5) are respectively communicated with the second working chamber of the spring compensation hydraulic cylinder (15) and the valve control retraction module, and the second manual opening valve (5) is used for manual emergency pressure relief compression return in a deep-sea environment; the high-pressure accumulator (3) is used as an oil tank of the deep-sea electro-hydraulic valve actuator.

3. The deep-sea electro-hydraulic valve actuator with redundancy retraction function according to claim 1, characterized in that: The first manual opening valve (4) and the second manual opening valve (5) further comprise a valve block buffer pad (4.7) located in the center of the interior of the valve block (4.6), the interior of the valve block (4.6) is provided with a communication hole coaxial with the valve rod (4.12) and communicating with the clamping groove, one end of the valve block buffer pad (4.7) is located in the communication hole and connected to the end face of the valve rod (4.12), the other end of the valve block buffer pad (4.7) is connected to the interior wall surface of the valve block (4.6), the valve block buffer pad (4.7) is a variable-diameter block, and the cross-sectional size of the other end of the valve block buffer pad (4.7) is greater than the size of the communication hole, so as to achieve buffering during the movement of the valve block (4.6).

4. The deep-sea electro-hydraulic valve actuator with redundancy retraction function according to claim 2, characterized in that: The integrated valve group module comprises a first two-way switch valve (6) and a second two-way switch valve (7) for oil pressure control, a first overflow valve (9) and a second overflow valve (10), a flow matching valve (11) for oil return, and a first one-way valve (18) and a second one-way valve (19) for oil supplement, the first two-way switch valve (6) and the second two-way switch valve (7) are respectively connected to the first working chamber and the second working chamber of the spring compensation hydraulic cylinder (15) and are both connected to the redundant pump control module; the oil inlet of the first overflow valve (9) and the oil inlet of the second overflow valve (10) are respectively connected to the first working chamber and the second working chamber of the spring compensation hydraulic cylinder (15), the oil outlets of the first overflow valve (9) and the second overflow valve (10) are merged and connected to the T port of the flow matching valve (11) and the valve control retraction module, the remaining two oil ports of the flow matching valve (11) are connected to the redundant pump control module and are arranged in parallel with the oil supply pipelines of the two working chambers of the spring compensation hydraulic cylinder (15); the oil inlets of the first one-way valve (18) and the second one-way valve (19) are respectively connected to the first working chamber and the second working chamber of the spring compensation hydraulic cylinder (15), and the oil outlets of the first one-way valve (18) and the second one-way valve (19) are respectively connected to the redundant pump control module.

5. The deep-sea electro-hydraulic valve actuator with redundancy retraction function according to claim 4, characterized in that: The redundant pump control module comprises a first plunger pump (13), a second plunger pump (14), a first motor (16) and a second motor (17), the first motor (16) drives the first plunger pump (13) as a main power source, the second motor (17) drives the second plunger pump (14) as an auxiliary power source, and the second motor (17) works in parallel with the first plunger pump (13) when the first plunger pump (13) fails or when the peak demand of the deep-sea electro-hydraulic valve actuator occurs; the oil inlets of the first plunger pump (13) and the second plunger pump (14) are connected to the second two-way switch valve (7), the first oil port of the flow matching valve (11) and the oil outlet of the first one-way valve (18), and the oil outlets of the first plunger pump (13) and the second plunger pump (14) are connected to the first two-way switch valve (6), the second oil port of the flow matching valve (11) and the oil outlet of the second one-way valve (19).

6. The deep-sea electro-hydraulic valve actuator with redundancy retraction function according to claim 5, characterized in that: The valve control retraction module comprises a third two-way switch valve (8) and a pressure compensator (12), the second working chamber of the spring compensation hydraulic cylinder (15) is connected in parallel with the third two-way switch valve (8) and the second manually opened valve (5) of the manual pressure relief retraction module, the oil outlet (4.8) of the second manually opened valve (5) is communicated with the pressure compensator (12), the oil outlets of the first overflow valve (9) and the second overflow valve (10) are merged and connected to the pressure compensator (12), and the pressure compensator (12) serves as an oil tank of the deep-sea electro-hydraulic valve actuator.

7. The deep-sea electro-hydraulic valve actuator with redundancy retraction function according to claim 1, characterized in that: The valve actuation module further comprises a switch valve block (2), the hydraulic cylinder in the first working chamber of the spring compensation hydraulic cylinder (15) is communicated with the Christmas tree main valve pipeline (1) through the switch valve block (2), and the switch valve block (2) is in an initial closed state; when the deep-sea electro-hydraulic valve actuator is extended, the switch valve block (2) is pushed to an opened state.

8. The valve control method of the deep-sea electro-hydraulic valve actuator with redundancy retraction function according to claim 6, characterized in that, Comprise: The deep-sea electro-hydraulic valve actuator is divided into a redundant pump control circuit, a valve control retraction circuit, a manual pressure increase retraction circuit and a manual pressure relief retraction circuit when the valve is controlled; when the deep-sea electro-hydraulic valve actuator is in a normal working state, the Christmas tree main valve pipeline (1) is in an opened state, the first two-way switch valve (6), the second two-way switch valve (7) and the third two-way switch valve (8) are closed, and the first manually opened valve (4) and the second manually opened valve (5) are closed.

9. The valve control method of the deep-sea electro-hydraulic valve actuator with redundancy retraction function according to claim 8, characterized in that: In the redundant pump control circuit, the first motor (16) drives the first plunger pump (13) to supply oil to the spring compensation hydraulic cylinder (15), the second motor (17) drives the second plunger pump (14) as a redundant power source, the first plunger pump (13) and the first motor (16) and the second plunger pump (14) and the second motor (17) are both power assemblies, when one of the power assemblies fails, the oil supply function of the failed power assembly is replaced by the other power assembly; when an output higher than a preset flow rate is required, the first plunger pump (13) and the second plunger pump (14) work in parallel, the communication of the first two-way switch valve (6) and the second two-way switch valve (7) realizes the pressure supply and oil return of the two working chambers of the spring compensation hydraulic cylinder (15), so as to ensure the stable retraction of the piston rod; In the valve control retraction circuit, the pressure compensator (12) recovers and compensates oil, the third two-way switch valve (8) is communicated with the second working chamber of the spring compensation hydraulic cylinder (15), when the third two-way switch valve (8) is driven to be opened, the oil in the second working chamber of the spring compensation hydraulic cylinder (15) is returned through the pressure compensator (12) to form a pressure relief path; the spring return mechanism in the spring compensation hydraulic cylinder (15) applies force in the retraction direction to push the piston rod to retract, so as to realize the closing of the deep-sea electro-hydraulic valve actuator; The manual pressure relief and compression circuit has a second manual opening valve (5) connected in parallel between the second working chamber of the spring compensation hydraulic cylinder (15) and the pressure compensator (12), when the second manual opening valve (5) is opened under the operation of the remotely operated vehicle (ROV), the oil in the second working chamber is discharged through the pressure compensator (12) to eliminate the residual pressure in the chamber, at this time, the spring return mechanism in the spring compensation hydraulic cylinder (15) immediately acts to push the piston rod to retract; In the manual pressure relief and compression circuit, the high-pressure accumulator (3) is connected in communication with the first working chamber of the spring compensation hydraulic cylinder (15) through an oil pipe; when the remotely operated vehicle (ROV) operates the first manual opening valve (4), the oil outlet (4.8) and the oil inlet (4.9) of the first manual opening valve (4) are switched to the communication position, the high-pressure oil stored in the high-pressure accumulator (3) directly enters the first working chamber of the spring compensation hydraulic cylinder (15), and the piston rod is driven to move in the retracting direction, thereby achieving forced retraction.

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